vendor/llvm/llvm-release_360-r226102

27 files changed, 4459 insertions, 2807 deletions

diff --git a/lib/Transforms/Utils/AddDiscriminators.cpp b/lib/Transforms/Utils/AddDiscriminators.cpp
index 196ac79aaf29..820544bcebf0 100644
--- a/lib/Transforms/Utils/AddDiscriminators.cpp
+++ b/lib/Transforms/Utils/AddDiscriminators.cpp
@@ -167,7 +167,7 @@ bool AddDiscriminators::runOnFunction(Function &F) {
   bool Changed = false;
   Module *M = F.getParent();
   LLVMContext &Ctx = M->getContext();
-  DIBuilder Builder(*M);
+  DIBuilder Builder(*M, /*AllowUnresolved*/ false);
 
   // Traverse all the blocks looking for instructions in different
   // blocks that are at the same file:line location.
@@ -193,13 +193,11 @@ bool AddDiscriminators::runOnFunction(Function &F) {
         // Create a new lexical scope and compute a new discriminator
         // number for it.
         StringRef Filename = FirstDIL.getFilename();
-        unsigned LineNumber = FirstDIL.getLineNumber();
-        unsigned ColumnNumber = FirstDIL.getColumnNumber();
         DIScope Scope = FirstDIL.getScope();
         DIFile File = Builder.createFile(Filename, Scope.getDirectory());
         unsigned Discriminator = FirstDIL.computeNewDiscriminator(Ctx);
-        DILexicalBlock NewScope = Builder.createLexicalBlock(
-            Scope, File, LineNumber, ColumnNumber, Discriminator);
+        DILexicalBlockFile NewScope =
+            Builder.createLexicalBlockFile(Scope, File, Discriminator);
         DILocation NewDIL = FirstDIL.copyWithNewScope(Ctx, NewScope);
         DebugLoc newDebugLoc = DebugLoc::getFromDILocation(NewDIL);
 
diff --git a/lib/Transforms/Utils/BasicBlockUtils.cpp b/lib/Transforms/Utils/BasicBlockUtils.cpp
index 602e8ba55107..983f025a1a3a 100644
--- a/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -265,6 +265,18 @@ BasicBlock *llvm::SplitEdge(BasicBlock *BB, BasicBlock *Succ, Pass *P) {
   return SplitBlock(BB, BB->getTerminator(), P);
 }
 
+unsigned llvm::SplitAllCriticalEdges(Function &F, Pass *P) {
+  unsigned NumBroken = 0;
+  for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
+    TerminatorInst *TI = I->getTerminator();
+    if (TI->getNumSuccessors() > 1 && !isa<IndirectBrInst>(TI))
+      for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
+        if (SplitCriticalEdge(TI, i, P))
+          ++NumBroken;
+  }
+  return NumBroken;
+}
+
 /// SplitBlock - Split the specified block at the specified instruction - every
 /// thing before SplitPt stays in Old and everything starting with SplitPt moves
 /// to a new block.  The two blocks are joined by an unconditional branch and
diff --git a/lib/Transforms/Utils/BreakCriticalEdges.cpp b/lib/Transforms/Utils/BreakCriticalEdges.cpp
index 80bd51637514..eda22cfc1bab 100644
--- a/lib/Transforms/Utils/BreakCriticalEdges.cpp
+++ b/lib/Transforms/Utils/BreakCriticalEdges.cpp
@@ -40,7 +40,11 @@ namespace {
       initializeBreakCriticalEdgesPass(*PassRegistry::getPassRegistry());
     }
 
-    bool runOnFunction(Function &F) override;
+    bool runOnFunction(Function &F) override {
+      unsigned N = SplitAllCriticalEdges(F, this);
+      NumBroken += N;
+      return N > 0;
+    }
 
     void getAnalysisUsage(AnalysisUsage &AU) const override {
       AU.addPreserved<DominatorTreeWrapperPass>();
@@ -62,24 +66,6 @@ FunctionPass *llvm::createBreakCriticalEdgesPass() {
   return new BreakCriticalEdges();
 }
 
-// runOnFunction - Loop over all of the edges in the CFG, breaking critical
-// edges as they are found.
-//
-bool BreakCriticalEdges::runOnFunction(Function &F) {
-  bool Changed = false;
-  for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
-    TerminatorInst *TI = I->getTerminator();
-    if (TI->getNumSuccessors() > 1 && !isa<IndirectBrInst>(TI))
-      for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
-        if (SplitCriticalEdge(TI, i, this)) {
-          ++NumBroken;
-          Changed = true;
-        }
-  }
-
-  return Changed;
-}
-
 //===----------------------------------------------------------------------===//
 //    Implementation of the external critical edge manipulation functions
 //===----------------------------------------------------------------------===//
diff --git a/lib/Transforms/Utils/BuildLibCalls.cpp b/lib/Transforms/Utils/BuildLibCalls.cpp
index be00b6956199..322485d9e32a 100644
--- a/lib/Transforms/Utils/BuildLibCalls.cpp
+++ b/lib/Transforms/Utils/BuildLibCalls.cpp
@@ -42,8 +42,7 @@ Value *llvm::EmitStrLen(Value *Ptr, IRBuilder<> &B, const DataLayout *TD,
   AttributeSet AS[2];
   AS[0] = AttributeSet::get(M->getContext(), 1, Attribute::NoCapture);
   Attribute::AttrKind AVs[2] = { Attribute::ReadOnly, Attribute::NoUnwind };
-  AS[1] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex,
-                            ArrayRef<Attribute::AttrKind>(AVs, 2));
+  AS[1] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex, AVs);
 
   LLVMContext &Context = B.GetInsertBlock()->getContext();
   Constant *StrLen = M->getOrInsertFunction("strlen",
@@ -51,7 +50,7 @@ Value *llvm::EmitStrLen(Value *Ptr, IRBuilder<> &B, const DataLayout *TD,
                                                               AS),
                                             TD->getIntPtrType(Context),
                                             B.getInt8PtrTy(),
-                                            NULL);
+                                            nullptr);
   CallInst *CI = B.CreateCall(StrLen, CastToCStr(Ptr, B), "strlen");
   if (const Function *F = dyn_cast<Function>(StrLen->stripPointerCasts()))
     CI->setCallingConv(F->getCallingConv());
@@ -71,8 +70,7 @@ Value *llvm::EmitStrNLen(Value *Ptr, Value *MaxLen, IRBuilder<> &B,
   AttributeSet AS[2];
   AS[0] = AttributeSet::get(M->getContext(), 1, Attribute::NoCapture);
   Attribute::AttrKind AVs[2] = { Attribute::ReadOnly, Attribute::NoUnwind };
-  AS[1] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex,
-                            ArrayRef<Attribute::AttrKind>(AVs, 2));
+  AS[1] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex, AVs);
 
   LLVMContext &Context = B.GetInsertBlock()->getContext();
   Constant *StrNLen = M->getOrInsertFunction("strnlen",
@@ -81,7 +79,7 @@ Value *llvm::EmitStrNLen(Value *Ptr, Value *MaxLen, IRBuilder<> &B,
                                              TD->getIntPtrType(Context),
                                              B.getInt8PtrTy(),
                                              TD->getIntPtrType(Context),
-                                             NULL);
+                                             nullptr);
   CallInst *CI = B.CreateCall2(StrNLen, CastToCStr(Ptr, B), MaxLen, "strnlen");
   if (const Function *F = dyn_cast<Function>(StrNLen->stripPointerCasts()))
     CI->setCallingConv(F->getCallingConv());
@@ -100,15 +98,14 @@ Value *llvm::EmitStrChr(Value *Ptr, char C, IRBuilder<> &B,
   Module *M = B.GetInsertBlock()->getParent()->getParent();
   Attribute::AttrKind AVs[2] = { Attribute::ReadOnly, Attribute::NoUnwind };
   AttributeSet AS =
-    AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex,
-                      ArrayRef<Attribute::AttrKind>(AVs, 2));
+    AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex, AVs);
 
   Type *I8Ptr = B.getInt8PtrTy();
   Type *I32Ty = B.getInt32Ty();
   Constant *StrChr = M->getOrInsertFunction("strchr",
                                             AttributeSet::get(M->getContext(),
                                                              AS),
-                                            I8Ptr, I8Ptr, I32Ty, NULL);
+                                            I8Ptr, I8Ptr, I32Ty, nullptr);
   CallInst *CI = B.CreateCall2(StrChr, CastToCStr(Ptr, B),
                                ConstantInt::get(I32Ty, C), "strchr");
   if (const Function *F = dyn_cast<Function>(StrChr->stripPointerCasts()))
@@ -128,8 +125,7 @@ Value *llvm::EmitStrNCmp(Value *Ptr1, Value *Ptr2, Value *Len,
   AS[0] = AttributeSet::get(M->getContext(), 1, Attribute::NoCapture);
   AS[1] = AttributeSet::get(M->getContext(), 2, Attribute::NoCapture);
   Attribute::AttrKind AVs[2] = { Attribute::ReadOnly, Attribute::NoUnwind };
-  AS[2] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex,
-                            ArrayRef<Attribute::AttrKind>(AVs, 2));
+  AS[2] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex, AVs);
 
   LLVMContext &Context = B.GetInsertBlock()->getContext();
   Value *StrNCmp = M->getOrInsertFunction("strncmp",
@@ -138,7 +134,7 @@ Value *llvm::EmitStrNCmp(Value *Ptr1, Value *Ptr2, Value *Len,
                                           B.getInt32Ty(),
                                           B.getInt8PtrTy(),
                                           B.getInt8PtrTy(),
-                                          TD->getIntPtrType(Context), NULL);
+                                          TD->getIntPtrType(Context), nullptr);
   CallInst *CI = B.CreateCall3(StrNCmp, CastToCStr(Ptr1, B),
                                CastToCStr(Ptr2, B), Len, "strncmp");
 
@@ -164,7 +160,7 @@ Value *llvm::EmitStrCpy(Value *Dst, Value *Src, IRBuilder<> &B,
   Type *I8Ptr = B.getInt8PtrTy();
   Value *StrCpy = M->getOrInsertFunction(Name,
                                          AttributeSet::get(M->getContext(), AS),
-                                         I8Ptr, I8Ptr, I8Ptr, NULL);
+                                         I8Ptr, I8Ptr, I8Ptr, nullptr);
   CallInst *CI = B.CreateCall2(StrCpy, CastToCStr(Dst, B), CastToCStr(Src, B),
                                Name);
   if (const Function *F = dyn_cast<Function>(StrCpy->stripPointerCasts()))
@@ -190,7 +186,7 @@ Value *llvm::EmitStrNCpy(Value *Dst, Value *Src, Value *Len,
                                           AttributeSet::get(M->getContext(),
                                                             AS),
                                           I8Ptr, I8Ptr, I8Ptr,
-                                          Len->getType(), NULL);
+                                          Len->getType(), nullptr);
   CallInst *CI = B.CreateCall3(StrNCpy, CastToCStr(Dst, B), CastToCStr(Src, B),
                                Len, "strncpy");
   if (const Function *F = dyn_cast<Function>(StrNCpy->stripPointerCasts()))
@@ -218,7 +214,7 @@ Value *llvm::EmitMemCpyChk(Value *Dst, Value *Src, Value *Len, Value *ObjSize,
                                          B.getInt8PtrTy(),
                                          B.getInt8PtrTy(),
                                          TD->getIntPtrType(Context),
-                                         TD->getIntPtrType(Context), NULL);
+                                         TD->getIntPtrType(Context), nullptr);
   Dst = CastToCStr(Dst, B);
   Src = CastToCStr(Src, B);
   CallInst *CI = B.CreateCall4(MemCpy, Dst, Src, Len, ObjSize);
@@ -238,8 +234,7 @@ Value *llvm::EmitMemChr(Value *Ptr, Value *Val,
   Module *M = B.GetInsertBlock()->getParent()->getParent();
   AttributeSet AS;
   Attribute::AttrKind AVs[2] = { Attribute::ReadOnly, Attribute::NoUnwind };
-  AS = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex,
-                         ArrayRef<Attribute::AttrKind>(AVs, 2));
+  AS = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex, AVs);
   LLVMContext &Context = B.GetInsertBlock()->getContext();
   Value *MemChr = M->getOrInsertFunction("memchr",
                                          AttributeSet::get(M->getContext(), AS),
@@ -247,7 +242,7 @@ Value *llvm::EmitMemChr(Value *Ptr, Value *Val,
                                          B.getInt8PtrTy(),
                                          B.getInt32Ty(),
                                          TD->getIntPtrType(Context),
-                                         NULL);
+                                         nullptr);
   CallInst *CI = B.CreateCall3(MemChr, CastToCStr(Ptr, B), Val, Len, "memchr");
 
   if (const Function *F = dyn_cast<Function>(MemChr->stripPointerCasts()))
@@ -268,8 +263,7 @@ Value *llvm::EmitMemCmp(Value *Ptr1, Value *Ptr2,
   AS[0] = AttributeSet::get(M->getContext(), 1, Attribute::NoCapture);
   AS[1] = AttributeSet::get(M->getContext(), 2, Attribute::NoCapture);
   Attribute::AttrKind AVs[2] = { Attribute::ReadOnly, Attribute::NoUnwind };
-  AS[2] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex,
-                            ArrayRef<Attribute::AttrKind>(AVs, 2));
+  AS[2] = AttributeSet::get(M->getContext(), AttributeSet::FunctionIndex, AVs);
 
   LLVMContext &Context = B.GetInsertBlock()->getContext();
   Value *MemCmp = M->getOrInsertFunction("memcmp",
@@ -277,7 +271,7 @@ Value *llvm::EmitMemCmp(Value *Ptr1, Value *Ptr2,
                                          B.getInt32Ty(),
                                          B.getInt8PtrTy(),
                                          B.getInt8PtrTy(),
-                                         TD->getIntPtrType(Context), NULL);
+                                         TD->getIntPtrType(Context), nullptr);
   CallInst *CI = B.CreateCall3(MemCmp, CastToCStr(Ptr1, B), CastToCStr(Ptr2, B),
                                Len, "memcmp");
 
@@ -313,7 +307,7 @@ Value *llvm::EmitUnaryFloatFnCall(Value *Op, StringRef Name, IRBuilder<> &B,
 
   Module *M = B.GetInsertBlock()->getParent()->getParent();
   Value *Callee = M->getOrInsertFunction(Name, Op->getType(),
-                                         Op->getType(), NULL);
+                                         Op->getType(), nullptr);
   CallInst *CI = B.CreateCall(Callee, Op, Name);
   CI->setAttributes(Attrs);
   if (const Function *F = dyn_cast<Function>(Callee->stripPointerCasts()))
@@ -334,7 +328,7 @@ Value *llvm::EmitBinaryFloatFnCall(Value *Op1, Value *Op2, StringRef Name,
 
   Module *M = B.GetInsertBlock()->getParent()->getParent();
   Value *Callee = M->getOrInsertFunction(Name, Op1->getType(),
-                                         Op1->getType(), Op2->getType(), NULL);
+                                         Op1->getType(), Op2->getType(), nullptr);
   CallInst *CI = B.CreateCall2(Callee, Op1, Op2, Name);
   CI->setAttributes(Attrs);
   if (const Function *F = dyn_cast<Function>(Callee->stripPointerCasts()))
@@ -352,7 +346,7 @@ Value *llvm::EmitPutChar(Value *Char, IRBuilder<> &B, const DataLayout *TD,
 
   Module *M = B.GetInsertBlock()->getParent()->getParent();
   Value *PutChar = M->getOrInsertFunction("putchar", B.getInt32Ty(),
-                                          B.getInt32Ty(), NULL);
+                                          B.getInt32Ty(), nullptr);
   CallInst *CI = B.CreateCall(PutChar,
                               B.CreateIntCast(Char,
                               B.getInt32Ty(),
@@ -382,7 +376,7 @@ Value *llvm::EmitPutS(Value *Str, IRBuilder<> &B, const DataLayout *TD,
                                        AttributeSet::get(M->getContext(), AS),
                                        B.getInt32Ty(),
                                        B.getInt8PtrTy(),
-                                       NULL);
+                                       nullptr);
   CallInst *CI = B.CreateCall(PutS, CastToCStr(Str, B), "puts");
   if (const Function *F = dyn_cast<Function>(PutS->stripPointerCasts()))
     CI->setCallingConv(F->getCallingConv());
@@ -407,12 +401,12 @@ Value *llvm::EmitFPutC(Value *Char, Value *File, IRBuilder<> &B,
                                AttributeSet::get(M->getContext(), AS),
                                B.getInt32Ty(),
                                B.getInt32Ty(), File->getType(),
-                               NULL);
+                               nullptr);
   else
     F = M->getOrInsertFunction("fputc",
                                B.getInt32Ty(),
                                B.getInt32Ty(),
-                               File->getType(), NULL);
+                               File->getType(), nullptr);
   Char = B.CreateIntCast(Char, B.getInt32Ty(), /*isSigned*/true,
                          "chari");
   CallInst *CI = B.CreateCall2(F, Char, File, "fputc");
@@ -442,11 +436,11 @@ Value *llvm::EmitFPutS(Value *Str, Value *File, IRBuilder<> &B,
                                AttributeSet::get(M->getContext(), AS),
                                B.getInt32Ty(),
                                B.getInt8PtrTy(),
-                               File->getType(), NULL);
+                               File->getType(), nullptr);
   else
     F = M->getOrInsertFunction(FPutsName, B.getInt32Ty(),
                                B.getInt8PtrTy(),
-                               File->getType(), NULL);
+                               File->getType(), nullptr);
   CallInst *CI = B.CreateCall2(F, CastToCStr(Str, B), File, "fputs");
 
   if (const Function *Fn = dyn_cast<Function>(F->stripPointerCasts()))
@@ -478,13 +472,13 @@ Value *llvm::EmitFWrite(Value *Ptr, Value *Size, Value *File,
                                B.getInt8PtrTy(),
                                TD->getIntPtrType(Context),
                                TD->getIntPtrType(Context),
-                               File->getType(), NULL);
+                               File->getType(), nullptr);
   else
     F = M->getOrInsertFunction(FWriteName, TD->getIntPtrType(Context),
                                B.getInt8PtrTy(),
                                TD->getIntPtrType(Context),
                                TD->getIntPtrType(Context),
-                               File->getType(), NULL);
+                               File->getType(), nullptr);
   CallInst *CI = B.CreateCall4(F, CastToCStr(Ptr, B), Size,
                         ConstantInt::get(TD->getIntPtrType(Context), 1), File);
 
@@ -492,135 +486,3 @@ Value *llvm::EmitFWrite(Value *Ptr, Value *Size, Value *File,
     CI->setCallingConv(Fn->getCallingConv());
   return CI;
 }
-
-SimplifyFortifiedLibCalls::~SimplifyFortifiedLibCalls() { }
-
-bool SimplifyFortifiedLibCalls::fold(CallInst *CI, const DataLayout *TD,
-                                     const TargetLibraryInfo *TLI) {
-  // We really need DataLayout for later.
-  if (!TD) return false;
-  
-  this->CI = CI;
-  Function *Callee = CI->getCalledFunction();
-  StringRef Name = Callee->getName();
-  FunctionType *FT = Callee->getFunctionType();
-  LLVMContext &Context = CI->getParent()->getContext();
-  IRBuilder<> B(CI);
-
-  if (Name == "__memcpy_chk") {
-    // Check if this has the right signature.
-    if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
-        !FT->getParamType(0)->isPointerTy() ||
-        !FT->getParamType(1)->isPointerTy() ||
-        FT->getParamType(2) != TD->getIntPtrType(Context) ||
-        FT->getParamType(3) != TD->getIntPtrType(Context))
-      return false;
-
-    if (isFoldable(3, 2, false)) {
-      B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
-                     CI->getArgOperand(2), 1);
-      replaceCall(CI->getArgOperand(0));
-      return true;
-    }
-    return false;
-  }
-
-  // Should be similar to memcpy.
-  if (Name == "__mempcpy_chk") {
-    return false;
-  }
-
-  if (Name == "__memmove_chk") {
-    // Check if this has the right signature.
-    if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
-        !FT->getParamType(0)->isPointerTy() ||
-        !FT->getParamType(1)->isPointerTy() ||
-        FT->getParamType(2) != TD->getIntPtrType(Context) ||
-        FT->getParamType(3) != TD->getIntPtrType(Context))
-      return false;
-
-    if (isFoldable(3, 2, false)) {
-      B.CreateMemMove(CI->getArgOperand(0), CI->getArgOperand(1),
-                      CI->getArgOperand(2), 1);
-      replaceCall(CI->getArgOperand(0));
-      return true;
-    }
-    return false;
-  }
-
-  if (Name == "__memset_chk") {
-    // Check if this has the right signature.
-    if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
-        !FT->getParamType(0)->isPointerTy() ||
-        !FT->getParamType(1)->isIntegerTy() ||
-        FT->getParamType(2) != TD->getIntPtrType(Context) ||
-        FT->getParamType(3) != TD->getIntPtrType(Context))
-      return false;
-
-    if (isFoldable(3, 2, false)) {
-      Value *Val = B.CreateIntCast(CI->getArgOperand(1), B.getInt8Ty(),
-                                   false);
-      B.CreateMemSet(CI->getArgOperand(0), Val, CI->getArgOperand(2), 1);
-      replaceCall(CI->getArgOperand(0));
-      return true;
-    }
-    return false;
-  }
-
-  if (Name == "__strcpy_chk" || Name == "__stpcpy_chk") {
-    // Check if this has the right signature.
-    if (FT->getNumParams() != 3 ||
-        FT->getReturnType() != FT->getParamType(0) ||
-        FT->getParamType(0) != FT->getParamType(1) ||
-        FT->getParamType(0) != Type::getInt8PtrTy(Context) ||
-        FT->getParamType(2) != TD->getIntPtrType(Context))
-      return 0;
-    
-    
-    // If a) we don't have any length information, or b) we know this will
-    // fit then just lower to a plain st[rp]cpy. Otherwise we'll keep our
-    // st[rp]cpy_chk call which may fail at runtime if the size is too long.
-    // TODO: It might be nice to get a maximum length out of the possible
-    // string lengths for varying.
-    if (isFoldable(2, 1, true)) {
-      Value *Ret = EmitStrCpy(CI->getArgOperand(0), CI->getArgOperand(1), B, TD,
-                              TLI, Name.substr(2, 6));
-      if (!Ret)
-        return false;
-      replaceCall(Ret);
-      return true;
-    }
-    return false;
-  }
-
-  if (Name == "__strncpy_chk" || Name == "__stpncpy_chk") {
-    // Check if this has the right signature.
-    if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
-        FT->getParamType(0) != FT->getParamType(1) ||
-        FT->getParamType(0) != Type::getInt8PtrTy(Context) ||
-        !FT->getParamType(2)->isIntegerTy() ||
-        FT->getParamType(3) != TD->getIntPtrType(Context))
-      return false;
-
-    if (isFoldable(3, 2, false)) {
-      Value *Ret = EmitStrNCpy(CI->getArgOperand(0), CI->getArgOperand(1),
-                               CI->getArgOperand(2), B, TD, TLI,
-                               Name.substr(2, 7));
-      if (!Ret)
-        return false;
-      replaceCall(Ret);
-      return true;
-    }
-    return false;
-  }
-
-  if (Name == "__strcat_chk") {
-    return false;
-  }
-
-  if (Name == "__strncat_chk") {
-    return false;
-  }
-
-  return false;
-}
diff --git a/lib/Transforms/Utils/CMakeLists.txt b/lib/Transforms/Utils/CMakeLists.txt
index fcf548f97c5d..6ce22b101825 100644
--- a/lib/Transforms/Utils/CMakeLists.txt
+++ b/lib/Transforms/Utils/CMakeLists.txt
@@ -1,16 +1,17 @@
 add_llvm_library(LLVMTransformUtils
-  AddDiscriminators.cpp
   ASanStackFrameLayout.cpp
+  AddDiscriminators.cpp
   BasicBlockUtils.cpp
   BreakCriticalEdges.cpp
   BuildLibCalls.cpp
   BypassSlowDivision.cpp
-  CtorUtils.cpp
   CloneFunction.cpp
   CloneModule.cpp
   CmpInstAnalysis.cpp
   CodeExtractor.cpp
+  CtorUtils.cpp
   DemoteRegToStack.cpp
+  FlattenCFG.cpp
   GlobalStatus.cpp
   InlineFunction.cpp
   InstructionNamer.cpp
@@ -29,10 +30,10 @@ add_llvm_library(LLVMTransformUtils
   PromoteMemoryToRegister.cpp
   SSAUpdater.cpp
   SimplifyCFG.cpp
-  FlattenCFG.cpp
   SimplifyIndVar.cpp
   SimplifyInstructions.cpp
   SimplifyLibCalls.cpp
+  SymbolRewriter.cpp
   UnifyFunctionExitNodes.cpp
   Utils.cpp
   ValueMapper.cpp
diff --git a/lib/Transforms/Utils/CloneFunction.cpp b/lib/Transforms/Utils/CloneFunction.cpp
index 5c8f20d5f884..96a763fac93b 100644
--- a/lib/Transforms/Utils/CloneFunction.cpp
+++ b/lib/Transforms/Utils/CloneFunction.cpp
@@ -164,14 +164,13 @@ static MDNode* FindSubprogram(const Function *F, DebugInfoFinder &Finder) {
 
 // Add an operand to an existing MDNode. The new operand will be added at the
 // back of the operand list.
-static void AddOperand(MDNode *Node, Value *Operand) {
-  SmallVector<Value*, 16> Operands;
-  for (unsigned i = 0; i < Node->getNumOperands(); i++) {
-    Operands.push_back(Node->getOperand(i));
-  }
-  Operands.push_back(Operand);
-  MDNode *NewNode = MDNode::get(Node->getContext(), Operands);
-  Node->replaceAllUsesWith(NewNode);
+static void AddOperand(DICompileUnit CU, DIArray SPs, Metadata *NewSP) {
+  SmallVector<Metadata *, 16> NewSPs;
+  NewSPs.reserve(SPs->getNumOperands() + 1);
+  for (unsigned I = 0, E = SPs->getNumOperands(); I != E; ++I)
+    NewSPs.push_back(SPs->getOperand(I));
+  NewSPs.push_back(NewSP);
+  CU.replaceSubprograms(DIArray(MDNode::get(CU->getContext(), NewSPs)));
 }
 
 // Clone the module-level debug info associated with OldFunc. The cloned data
@@ -187,7 +186,7 @@ static void CloneDebugInfoMetadata(Function *NewFunc, const Function *OldFunc,
   // Ensure that OldFunc appears in the map.
   // (if it's already there it must point to NewFunc anyway)
   VMap[OldFunc] = NewFunc;
-  DISubprogram NewSubprogram(MapValue(OldSubprogramMDNode, VMap));
+  DISubprogram NewSubprogram(MapMetadata(OldSubprogramMDNode, VMap));
 
   for (DICompileUnit CU : Finder.compile_units()) {
     DIArray Subprograms(CU.getSubprograms());
@@ -196,7 +195,8 @@ static void CloneDebugInfoMetadata(Function *NewFunc, const Function *OldFunc,
     // also contain the new one.
     for (unsigned i = 0; i < Subprograms.getNumElements(); i++) {
       if ((MDNode*)Subprograms.getElement(i) == OldSubprogramMDNode) {
-        AddOperand(Subprograms, NewSubprogram);
+        AddOperand(CU, Subprograms, NewSubprogram);
+        break;
       }
     }
   }
diff --git a/lib/Transforms/Utils/CloneModule.cpp b/lib/Transforms/Utils/CloneModule.cpp
index 3f75b3e677ee..fae9ff5bce0f 100644
--- a/lib/Transforms/Utils/CloneModule.cpp
+++ b/lib/Transforms/Utils/CloneModule.cpp
@@ -17,6 +17,7 @@
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Module.h"
 #include "llvm/Transforms/Utils/ValueMapper.h"
+#include "llvm-c/Core.h"
 using namespace llvm;
 
 /// CloneModule - Return an exact copy of the specified module.  This is not as
@@ -108,7 +109,7 @@ Module *llvm::CloneModule(const Module *M, ValueToValueMapTy &VMap) {
        I != E; ++I) {
     GlobalAlias *GA = cast<GlobalAlias>(VMap[I]);
     if (const Constant *C = I->getAliasee())
-      GA->setAliasee(cast<GlobalObject>(MapValue(C, VMap)));
+      GA->setAliasee(MapValue(C, VMap));
   }
 
   // And named metadata....
@@ -117,8 +118,16 @@ Module *llvm::CloneModule(const Module *M, ValueToValueMapTy &VMap) {
     const NamedMDNode &NMD = *I;
     NamedMDNode *NewNMD = New->getOrInsertNamedMetadata(NMD.getName());
     for (unsigned i = 0, e = NMD.getNumOperands(); i != e; ++i)
-      NewNMD->addOperand(MapValue(NMD.getOperand(i), VMap));
+      NewNMD->addOperand(MapMetadata(NMD.getOperand(i), VMap));
   }
 
   return New;
 }
+
+extern "C" {
+
+LLVMModuleRef LLVMCloneModule(LLVMModuleRef M) {
+  return wrap(CloneModule(unwrap(M)));
+}
+
+}
diff --git a/lib/Transforms/Utils/CtorUtils.cpp b/lib/Transforms/Utils/CtorUtils.cpp
index a3594248de0c..26875e837b8b 100644
--- a/lib/Transforms/Utils/CtorUtils.cpp
+++ b/lib/Transforms/Utils/CtorUtils.cpp
@@ -11,6 +11,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/ADT/BitVector.h"
 #include "llvm/Transforms/Utils/CtorUtils.h"
 #include "llvm/IR/Constants.h"
 #include "llvm/IR/Function.h"
@@ -24,41 +25,22 @@
 namespace llvm {
 
 namespace {
-/// Given a specified llvm.global_ctors list, install the
-/// specified array.
-void installGlobalCtors(GlobalVariable *GCL,
-                        const std::vector<Function *> &Ctors) {
-  // If we made a change, reassemble the initializer list.
-  Constant *CSVals[3];
-
-  StructType *StructTy =
-      cast<StructType>(GCL->getType()->getElementType()->getArrayElementType());
-
-  // Create the new init list.
-  std::vector<Constant *> CAList;
-  for (Function *F : Ctors) {
-    Type *Int32Ty = Type::getInt32Ty(GCL->getContext());
-    if (F) {
-      CSVals[0] = ConstantInt::get(Int32Ty, 65535);
-      CSVals[1] = F;
-    } else {
-      CSVals[0] = ConstantInt::get(Int32Ty, 0x7fffffff);
-      CSVals[1] = Constant::getNullValue(StructTy->getElementType(1));
-    }
-    // FIXME: Only allow the 3-field form in LLVM 4.0.
-    size_t NumElts = StructTy->getNumElements();
-    if (NumElts > 2)
-      CSVals[2] = Constant::getNullValue(StructTy->getElementType(2));
-    CAList.push_back(
-        ConstantStruct::get(StructTy, makeArrayRef(CSVals, NumElts)));
-  }
-
-  // Create the array initializer.
-  Constant *CA =
-      ConstantArray::get(ArrayType::get(StructTy, CAList.size()), CAList);
+/// Given a specified llvm.global_ctors list, remove the listed elements.
+void removeGlobalCtors(GlobalVariable *GCL, const BitVector &CtorsToRemove) {
+  // Filter out the initializer elements to remove.
+  ConstantArray *OldCA = cast<ConstantArray>(GCL->getInitializer());
+  SmallVector<Constant *, 10> CAList;
+  for (unsigned I = 0, E = OldCA->getNumOperands(); I < E; ++I)
+    if (!CtorsToRemove.test(I))
+      CAList.push_back(OldCA->getOperand(I));
+
+  // Create the new array initializer.
+  ArrayType *ATy =
+      ArrayType::get(OldCA->getType()->getElementType(), CAList.size());
+  Constant *CA = ConstantArray::get(ATy, CAList);
 
   // If we didn't change the number of elements, don't create a new GV.
-  if (CA->getType() == GCL->getInitializer()->getType()) {
+  if (CA->getType() == OldCA->getType()) {
     GCL->setInitializer(CA);
     return;
   }
@@ -82,7 +64,7 @@ void installGlobalCtors(GlobalVariable *GCL,
 
 /// Given a llvm.global_ctors list that we can understand,
 /// return a list of the functions and null terminator as a vector.
-std::vector<Function*> parseGlobalCtors(GlobalVariable *GV) {
+std::vector<Function *> parseGlobalCtors(GlobalVariable *GV) {
   if (GV->getInitializer()->isNullValue())
     return std::vector<Function *>();
   ConstantArray *CA = cast<ConstantArray>(GV->getInitializer());
@@ -147,17 +129,15 @@ bool optimizeGlobalCtorsList(Module &M,
   bool MadeChange = false;
 
   // Loop over global ctors, optimizing them when we can.
-  for (unsigned i = 0; i != Ctors.size(); ++i) {
+  unsigned NumCtors = Ctors.size();
+  BitVector CtorsToRemove(NumCtors);
+  for (unsigned i = 0; i != Ctors.size() && NumCtors > 0; ++i) {
     Function *F = Ctors[i];
     // Found a null terminator in the middle of the list, prune off the rest of
     // the list.
-    if (!F) {
-      if (i != Ctors.size() - 1) {
-        Ctors.resize(i + 1);
-        MadeChange = true;
-      }
-      break;
-    }
+    if (!F)
+      continue;
+
     DEBUG(dbgs() << "Optimizing Global Constructor: " << *F << "\n");
 
     // We cannot simplify external ctor functions.
@@ -166,9 +146,10 @@ bool optimizeGlobalCtorsList(Module &M,
 
     // If we can evaluate the ctor at compile time, do.
     if (ShouldRemove(F)) {
-      Ctors.erase(Ctors.begin() + i);
+      Ctors[i] = nullptr;
+      CtorsToRemove.set(i);
+      NumCtors--;
       MadeChange = true;
-      --i;
       continue;
     }
   }
@@ -176,7 +157,7 @@ bool optimizeGlobalCtorsList(Module &M,
   if (!MadeChange)
     return false;
 
-  installGlobalCtors(GlobalCtors, Ctors);
+  removeGlobalCtors(GlobalCtors, CtorsToRemove);
   return true;
 }
 
diff --git a/lib/Transforms/Utils/FlattenCFG.cpp b/lib/Transforms/Utils/FlattenCFG.cpp
index 51ead40c916e..4eb3e3dd17d2 100644
--- a/lib/Transforms/Utils/FlattenCFG.cpp
+++ b/lib/Transforms/Utils/FlattenCFG.cpp
@@ -238,9 +238,13 @@ bool FlattenCFGOpt::FlattenParallelAndOr(BasicBlock *BB, IRBuilder<> &Builder,
     // Do branch inversion.
     BasicBlock *CurrBlock = LastCondBlock;
     bool EverChanged = false;
-    while (1) {
+    for (;CurrBlock != FirstCondBlock;
+          CurrBlock = CurrBlock->getSinglePredecessor()) {
       BranchInst *BI = dyn_cast<BranchInst>(CurrBlock->getTerminator());
       CmpInst *CI = dyn_cast<CmpInst>(BI->getCondition());
+      if (!CI)
+        continue;
+
       CmpInst::Predicate Predicate = CI->getPredicate();
       // Canonicalize icmp_ne -> icmp_eq, fcmp_one -> fcmp_oeq
       if ((Predicate == CmpInst::ICMP_NE) || (Predicate == CmpInst::FCMP_ONE)) {
@@ -248,9 +252,6 @@ bool FlattenCFGOpt::FlattenParallelAndOr(BasicBlock *BB, IRBuilder<> &Builder,
         BI->swapSuccessors();
         EverChanged = true;
       }
-      if (CurrBlock == FirstCondBlock)
-        break;
-      CurrBlock = CurrBlock->getSinglePredecessor();
     }
     return EverChanged;
   }
diff --git a/lib/Transforms/Utils/GlobalStatus.cpp b/lib/Transforms/Utils/GlobalStatus.cpp
index 12057e4b929c..52e2d59557fa 100644
--- a/lib/Transforms/Utils/GlobalStatus.cpp
+++ b/lib/Transforms/Utils/GlobalStatus.cpp
@@ -35,6 +35,9 @@ bool llvm::isSafeToDestroyConstant(const Constant *C) {
   if (isa<GlobalValue>(C))
     return false;
 
+  if (isa<ConstantInt>(C) || isa<ConstantFP>(C))
+    return false;
+
   for (const User *U : C->users())
     if (const Constant *CU = dyn_cast<Constant>(U)) {
       if (!isSafeToDestroyConstant(CU))
@@ -45,7 +48,7 @@ bool llvm::isSafeToDestroyConstant(const Constant *C) {
 }
 
 static bool analyzeGlobalAux(const Value *V, GlobalStatus &GS,
-                             SmallPtrSet<const PHINode *, 16> &PhiUsers) {
+                             SmallPtrSetImpl<const PHINode *> &PhiUsers) {
   for (const Use &U : V->uses()) {
     const User *UR = U.getUser();
     if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(UR)) {
@@ -130,7 +133,7 @@ static bool analyzeGlobalAux(const Value *V, GlobalStatus &GS,
       } else if (const PHINode *PN = dyn_cast<PHINode>(I)) {
         // PHI nodes we can check just like select or GEP instructions, but we
         // have to be careful about infinite recursion.
-        if (PhiUsers.insert(PN)) // Not already visited.
+        if (PhiUsers.insert(PN).second) // Not already visited.
           if (analyzeGlobalAux(I, GS, PhiUsers))
             return true;
       } else if (isa<CmpInst>(I)) {
diff --git a/lib/Transforms/Utils/InlineFunction.cpp b/lib/Transforms/Utils/InlineFunction.cpp
index f0a9f2b1fcb3..2a86eb598d4d 100644
--- a/lib/Transforms/Utils/InlineFunction.cpp
+++ b/lib/Transforms/Utils/InlineFunction.cpp
@@ -13,10 +13,16 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Transforms/Utils/Cloning.h"
+#include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/StringExtras.h"
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/AssumptionCache.h"
 #include "llvm/Analysis/CallGraph.h"
+#include "llvm/Analysis/CaptureTracking.h"
 #include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/CallSite.h"
 #include "llvm/IR/CFG.h"
@@ -24,14 +30,28 @@
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/DebugInfo.h"
 #include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Dominators.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/MDBuilder.h"
 #include "llvm/IR/Module.h"
 #include "llvm/Transforms/Utils/Local.h"
+#include "llvm/Support/CommandLine.h"
+#include <algorithm>
 using namespace llvm;
 
+static cl::opt<bool>
+EnableNoAliasConversion("enable-noalias-to-md-conversion", cl::init(true),
+  cl::Hidden,
+  cl::desc("Convert noalias attributes to metadata during inlining."));
+
+static cl::opt<bool>
+PreserveAlignmentAssumptions("preserve-alignment-assumptions-during-inlining",
+  cl::init(true), cl::Hidden,
+  cl::desc("Convert align attributes to assumptions during inlining."));
+
 bool llvm::InlineFunction(CallInst *CI, InlineFunctionInfo &IFI,
                           bool InsertLifetime) {
   return InlineFunction(CallSite(CI), IFI, InsertLifetime);
@@ -84,7 +104,7 @@ namespace {
     /// split the landing pad block after the landingpad instruction and jump
     /// to there.
     void forwardResume(ResumeInst *RI,
-                       SmallPtrSet<LandingPadInst*, 16> &InlinedLPads);
+                       SmallPtrSetImpl<LandingPadInst*> &InlinedLPads);
 
     /// addIncomingPHIValuesFor - Add incoming-PHI values to the unwind
     /// destination block for the given basic block, using the values for the
@@ -143,7 +163,7 @@ BasicBlock *InvokeInliningInfo::getInnerResumeDest() {
 /// branch. When there is more than one predecessor, we need to split the
 /// landing pad block after the landingpad instruction and jump to there.
 void InvokeInliningInfo::forwardResume(ResumeInst *RI,
-                               SmallPtrSet<LandingPadInst*, 16> &InlinedLPads) {
+                               SmallPtrSetImpl<LandingPadInst*> &InlinedLPads) {
   BasicBlock *Dest = getInnerResumeDest();
   BasicBlock *Src = RI->getParent();
 
@@ -233,9 +253,7 @@ static void HandleInlinedInvoke(InvokeInst *II, BasicBlock *FirstNewBlock,
   // Append the clauses from the outer landing pad instruction into the inlined
   // landing pad instructions.
   LandingPadInst *OuterLPad = Invoke.getLandingPadInst();
-  for (SmallPtrSet<LandingPadInst*, 16>::iterator I = InlinedLPads.begin(),
-         E = InlinedLPads.end(); I != E; ++I) {
-    LandingPadInst *InlinedLPad = *I;
+  for (LandingPadInst *InlinedLPad : InlinedLPads) {
     unsigned OuterNum = OuterLPad->getNumClauses();
     InlinedLPad->reserveClauses(OuterNum);
     for (unsigned OuterIdx = 0; OuterIdx != OuterNum; ++OuterIdx)
@@ -260,6 +278,387 @@ static void HandleInlinedInvoke(InvokeInst *II, BasicBlock *FirstNewBlock,
   InvokeDest->removePredecessor(II->getParent());
 }
 
+/// CloneAliasScopeMetadata - When inlining a function that contains noalias
+/// scope metadata, this metadata needs to be cloned so that the inlined blocks
+/// have different "unqiue scopes" at every call site. Were this not done, then
+/// aliasing scopes from a function inlined into a caller multiple times could
+/// not be differentiated (and this would lead to miscompiles because the
+/// non-aliasing property communicated by the metadata could have
+/// call-site-specific control dependencies).
+static void CloneAliasScopeMetadata(CallSite CS, ValueToValueMapTy &VMap) {
+  const Function *CalledFunc = CS.getCalledFunction();
+  SetVector<const MDNode *> MD;
+
+  // Note: We could only clone the metadata if it is already used in the
+  // caller. I'm omitting that check here because it might confuse
+  // inter-procedural alias analysis passes. We can revisit this if it becomes
+  // an efficiency or overhead problem.
+
+  for (Function::const_iterator I = CalledFunc->begin(), IE = CalledFunc->end();
+       I != IE; ++I)
+    for (BasicBlock::const_iterator J = I->begin(), JE = I->end(); J != JE; ++J) {
+      if (const MDNode *M = J->getMetadata(LLVMContext::MD_alias_scope))
+        MD.insert(M);
+      if (const MDNode *M = J->getMetadata(LLVMContext::MD_noalias))
+        MD.insert(M);
+    }
+
+  if (MD.empty())
+    return;
+
+  // Walk the existing metadata, adding the complete (perhaps cyclic) chain to
+  // the set.
+  SmallVector<const Metadata *, 16> Queue(MD.begin(), MD.end());
+  while (!Queue.empty()) {
+    const MDNode *M = cast<MDNode>(Queue.pop_back_val());
+    for (unsigned i = 0, ie = M->getNumOperands(); i != ie; ++i)
+      if (const MDNode *M1 = dyn_cast<MDNode>(M->getOperand(i)))
+        if (MD.insert(M1))
+          Queue.push_back(M1);
+  }
+
+  // Now we have a complete set of all metadata in the chains used to specify
+  // the noalias scopes and the lists of those scopes.
+  SmallVector<MDNode *, 16> DummyNodes;
+  DenseMap<const MDNode *, TrackingMDNodeRef> MDMap;
+  for (SetVector<const MDNode *>::iterator I = MD.begin(), IE = MD.end();
+       I != IE; ++I) {
+    MDNode *Dummy = MDNode::getTemporary(CalledFunc->getContext(), None);
+    DummyNodes.push_back(Dummy);
+    MDMap[*I].reset(Dummy);
+  }
+
+  // Create new metadata nodes to replace the dummy nodes, replacing old
+  // metadata references with either a dummy node or an already-created new
+  // node.
+  for (SetVector<const MDNode *>::iterator I = MD.begin(), IE = MD.end();
+       I != IE; ++I) {
+    SmallVector<Metadata *, 4> NewOps;
+    for (unsigned i = 0, ie = (*I)->getNumOperands(); i != ie; ++i) {
+      const Metadata *V = (*I)->getOperand(i);
+      if (const MDNode *M = dyn_cast<MDNode>(V))
+        NewOps.push_back(MDMap[M]);
+      else
+        NewOps.push_back(const_cast<Metadata *>(V));
+    }
+
+    MDNode *NewM = MDNode::get(CalledFunc->getContext(), NewOps);
+    MDNodeFwdDecl *TempM = cast<MDNodeFwdDecl>(MDMap[*I]);
+
+    TempM->replaceAllUsesWith(NewM);
+  }
+
+  // Now replace the metadata in the new inlined instructions with the
+  // repacements from the map.
+  for (ValueToValueMapTy::iterator VMI = VMap.begin(), VMIE = VMap.end();
+       VMI != VMIE; ++VMI) {
+    if (!VMI->second)
+      continue;
+
+    Instruction *NI = dyn_cast<Instruction>(VMI->second);
+    if (!NI)
+      continue;
+
+    if (MDNode *M = NI->getMetadata(LLVMContext::MD_alias_scope)) {
+      MDNode *NewMD = MDMap[M];
+      // If the call site also had alias scope metadata (a list of scopes to
+      // which instructions inside it might belong), propagate those scopes to
+      // the inlined instructions.
+      if (MDNode *CSM =
+              CS.getInstruction()->getMetadata(LLVMContext::MD_alias_scope))
+        NewMD = MDNode::concatenate(NewMD, CSM);
+      NI->setMetadata(LLVMContext::MD_alias_scope, NewMD);
+    } else if (NI->mayReadOrWriteMemory()) {
+      if (MDNode *M =
+              CS.getInstruction()->getMetadata(LLVMContext::MD_alias_scope))
+        NI->setMetadata(LLVMContext::MD_alias_scope, M);
+    }
+
+    if (MDNode *M = NI->getMetadata(LLVMContext::MD_noalias)) {
+      MDNode *NewMD = MDMap[M];
+      // If the call site also had noalias metadata (a list of scopes with
+      // which instructions inside it don't alias), propagate those scopes to
+      // the inlined instructions.
+      if (MDNode *CSM =
+              CS.getInstruction()->getMetadata(LLVMContext::MD_noalias))
+        NewMD = MDNode::concatenate(NewMD, CSM);
+      NI->setMetadata(LLVMContext::MD_noalias, NewMD);
+    } else if (NI->mayReadOrWriteMemory()) {
+      if (MDNode *M = CS.getInstruction()->getMetadata(LLVMContext::MD_noalias))
+        NI->setMetadata(LLVMContext::MD_noalias, M);
+    }
+  }
+
+  // Now that everything has been replaced, delete the dummy nodes.
+  for (unsigned i = 0, ie = DummyNodes.size(); i != ie; ++i)
+    MDNode::deleteTemporary(DummyNodes[i]);
+}
+
+/// AddAliasScopeMetadata - If the inlined function has noalias arguments, then
+/// add new alias scopes for each noalias argument, tag the mapped noalias
+/// parameters with noalias metadata specifying the new scope, and tag all
+/// non-derived loads, stores and memory intrinsics with the new alias scopes.
+static void AddAliasScopeMetadata(CallSite CS, ValueToValueMapTy &VMap,
+                                  const DataLayout *DL, AliasAnalysis *AA) {
+  if (!EnableNoAliasConversion)
+    return;
+
+  const Function *CalledFunc = CS.getCalledFunction();
+  SmallVector<const Argument *, 4> NoAliasArgs;
+
+  for (Function::const_arg_iterator I = CalledFunc->arg_begin(),
+       E = CalledFunc->arg_end(); I != E; ++I) {
+    if (I->hasNoAliasAttr() && !I->hasNUses(0))
+      NoAliasArgs.push_back(I);
+  }
+
+  if (NoAliasArgs.empty())
+    return;
+
+  // To do a good job, if a noalias variable is captured, we need to know if
+  // the capture point dominates the particular use we're considering.
+  DominatorTree DT;
+  DT.recalculate(const_cast<Function&>(*CalledFunc));
+
+  // noalias indicates that pointer values based on the argument do not alias
+  // pointer values which are not based on it. So we add a new "scope" for each
+  // noalias function argument. Accesses using pointers based on that argument
+  // become part of that alias scope, accesses using pointers not based on that
+  // argument are tagged as noalias with that scope.
+
+  DenseMap<const Argument *, MDNode *> NewScopes;
+  MDBuilder MDB(CalledFunc->getContext());
+
+  // Create a new scope domain for this function.
+  MDNode *NewDomain =
+    MDB.createAnonymousAliasScopeDomain(CalledFunc->getName());
+  for (unsigned i = 0, e = NoAliasArgs.size(); i != e; ++i) {
+    const Argument *A = NoAliasArgs[i];
+
+    std::string Name = CalledFunc->getName();
+    if (A->hasName()) {
+      Name += ": %";
+      Name += A->getName();
+    } else {
+      Name += ": argument ";
+      Name += utostr(i);
+    }
+
+    // Note: We always create a new anonymous root here. This is true regardless
+    // of the linkage of the callee because the aliasing "scope" is not just a
+    // property of the callee, but also all control dependencies in the caller.
+    MDNode *NewScope = MDB.createAnonymousAliasScope(NewDomain, Name);
+    NewScopes.insert(std::make_pair(A, NewScope));
+  }
+
+  // Iterate over all new instructions in the map; for all memory-access
+  // instructions, add the alias scope metadata.
+  for (ValueToValueMapTy::iterator VMI = VMap.begin(), VMIE = VMap.end();
+       VMI != VMIE; ++VMI) {
+    if (const Instruction *I = dyn_cast<Instruction>(VMI->first)) {
+      if (!VMI->second)
+        continue;
+
+      Instruction *NI = dyn_cast<Instruction>(VMI->second);
+      if (!NI)
+        continue;
+
+      bool IsArgMemOnlyCall = false, IsFuncCall = false;
+      SmallVector<const Value *, 2> PtrArgs;
+
+      if (const LoadInst *LI = dyn_cast<LoadInst>(I))
+        PtrArgs.push_back(LI->getPointerOperand());
+      else if (const StoreInst *SI = dyn_cast<StoreInst>(I))
+        PtrArgs.push_back(SI->getPointerOperand());
+      else if (const VAArgInst *VAAI = dyn_cast<VAArgInst>(I))
+        PtrArgs.push_back(VAAI->getPointerOperand());
+      else if (const AtomicCmpXchgInst *CXI = dyn_cast<AtomicCmpXchgInst>(I))
+        PtrArgs.push_back(CXI->getPointerOperand());
+      else if (const AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(I))
+        PtrArgs.push_back(RMWI->getPointerOperand());
+      else if (ImmutableCallSite ICS = ImmutableCallSite(I)) {
+        // If we know that the call does not access memory, then we'll still
+        // know that about the inlined clone of this call site, and we don't
+        // need to add metadata.
+        if (ICS.doesNotAccessMemory())
+          continue;
+
+        IsFuncCall = true;
+        if (AA) {
+          AliasAnalysis::ModRefBehavior MRB = AA->getModRefBehavior(ICS);
+          if (MRB == AliasAnalysis::OnlyAccessesArgumentPointees ||
+              MRB == AliasAnalysis::OnlyReadsArgumentPointees)
+            IsArgMemOnlyCall = true;
+        }
+
+        for (ImmutableCallSite::arg_iterator AI = ICS.arg_begin(),
+             AE = ICS.arg_end(); AI != AE; ++AI) {
+          // We need to check the underlying objects of all arguments, not just
+          // the pointer arguments, because we might be passing pointers as
+          // integers, etc.
+          // However, if we know that the call only accesses pointer arguments,
+          // then we only need to check the pointer arguments.
+          if (IsArgMemOnlyCall && !(*AI)->getType()->isPointerTy())
+            continue;
+
+          PtrArgs.push_back(*AI);
+        }
+      }
+
+      // If we found no pointers, then this instruction is not suitable for
+      // pairing with an instruction to receive aliasing metadata.
+      // However, if this is a call, this we might just alias with none of the
+      // noalias arguments.
+      if (PtrArgs.empty() && !IsFuncCall)
+        continue;
+
+      // It is possible that there is only one underlying object, but you
+      // need to go through several PHIs to see it, and thus could be
+      // repeated in the Objects list.
+      SmallPtrSet<const Value *, 4> ObjSet;
+      SmallVector<Metadata *, 4> Scopes, NoAliases;
+
+      SmallSetVector<const Argument *, 4> NAPtrArgs;
+      for (unsigned i = 0, ie = PtrArgs.size(); i != ie; ++i) {
+        SmallVector<Value *, 4> Objects;
+        GetUnderlyingObjects(const_cast<Value*>(PtrArgs[i]),
+                             Objects, DL, /* MaxLookup = */ 0);
+
+        for (Value *O : Objects)
+          ObjSet.insert(O);
+      }
+
+      // Figure out if we're derived from anything that is not a noalias
+      // argument.
+      bool CanDeriveViaCapture = false, UsesAliasingPtr = false;
+      for (const Value *V : ObjSet) {
+        // Is this value a constant that cannot be derived from any pointer
+        // value (we need to exclude constant expressions, for example, that
+        // are formed from arithmetic on global symbols).
+        bool IsNonPtrConst = isa<ConstantInt>(V) || isa<ConstantFP>(V) ||
+                             isa<ConstantPointerNull>(V) ||
+                             isa<ConstantDataVector>(V) || isa<UndefValue>(V);
+        if (IsNonPtrConst)
+          continue;
+
+        // If this is anything other than a noalias argument, then we cannot
+        // completely describe the aliasing properties using alias.scope
+        // metadata (and, thus, won't add any).
+        if (const Argument *A = dyn_cast<Argument>(V)) {
+          if (!A->hasNoAliasAttr())
+            UsesAliasingPtr = true;
+        } else {
+          UsesAliasingPtr = true;
+        }
+
+        // If this is not some identified function-local object (which cannot
+        // directly alias a noalias argument), or some other argument (which,
+        // by definition, also cannot alias a noalias argument), then we could
+        // alias a noalias argument that has been captured).
+        if (!isa<Argument>(V) &&
+            !isIdentifiedFunctionLocal(const_cast<Value*>(V)))
+          CanDeriveViaCapture = true;
+      }
+
+      // A function call can always get captured noalias pointers (via other
+      // parameters, globals, etc.).
+      if (IsFuncCall && !IsArgMemOnlyCall)
+        CanDeriveViaCapture = true;
+
+      // First, we want to figure out all of the sets with which we definitely
+      // don't alias. Iterate over all noalias set, and add those for which:
+      //   1. The noalias argument is not in the set of objects from which we
+      //      definitely derive.
+      //   2. The noalias argument has not yet been captured.
+      // An arbitrary function that might load pointers could see captured
+      // noalias arguments via other noalias arguments or globals, and so we
+      // must always check for prior capture.
+      for (const Argument *A : NoAliasArgs) {
+        if (!ObjSet.count(A) && (!CanDeriveViaCapture ||
+                                 // It might be tempting to skip the
+                                 // PointerMayBeCapturedBefore check if
+                                 // A->hasNoCaptureAttr() is true, but this is
+                                 // incorrect because nocapture only guarantees
+                                 // that no copies outlive the function, not
+                                 // that the value cannot be locally captured.
+                                 !PointerMayBeCapturedBefore(A,
+                                   /* ReturnCaptures */ false,
+                                   /* StoreCaptures */ false, I, &DT)))
+          NoAliases.push_back(NewScopes[A]);
+      }
+
+      if (!NoAliases.empty())
+        NI->setMetadata(LLVMContext::MD_noalias,
+                        MDNode::concatenate(
+                            NI->getMetadata(LLVMContext::MD_noalias),
+                            MDNode::get(CalledFunc->getContext(), NoAliases)));
+
+      // Next, we want to figure out all of the sets to which we might belong.
+      // We might belong to a set if the noalias argument is in the set of
+      // underlying objects. If there is some non-noalias argument in our list
+      // of underlying objects, then we cannot add a scope because the fact
+      // that some access does not alias with any set of our noalias arguments
+      // cannot itself guarantee that it does not alias with this access
+      // (because there is some pointer of unknown origin involved and the
+      // other access might also depend on this pointer). We also cannot add
+      // scopes to arbitrary functions unless we know they don't access any
+      // non-parameter pointer-values.
+      bool CanAddScopes = !UsesAliasingPtr;
+      if (CanAddScopes && IsFuncCall)
+        CanAddScopes = IsArgMemOnlyCall;
+
+      if (CanAddScopes)
+        for (const Argument *A : NoAliasArgs) {
+          if (ObjSet.count(A))
+            Scopes.push_back(NewScopes[A]);
+        }
+
+      if (!Scopes.empty())
+        NI->setMetadata(
+            LLVMContext::MD_alias_scope,
+            MDNode::concatenate(NI->getMetadata(LLVMContext::MD_alias_scope),
+                                MDNode::get(CalledFunc->getContext(), Scopes)));
+    }
+  }
+}
+
+/// If the inlined function has non-byval align arguments, then
+/// add @llvm.assume-based alignment assumptions to preserve this information.
+static void AddAlignmentAssumptions(CallSite CS, InlineFunctionInfo &IFI) {
+  if (!PreserveAlignmentAssumptions || !IFI.DL)
+    return;
+
+  // To avoid inserting redundant assumptions, we should check for assumptions
+  // already in the caller. To do this, we might need a DT of the caller.
+  DominatorTree DT;
+  bool DTCalculated = false;
+
+  Function *CalledFunc = CS.getCalledFunction();
+  for (Function::arg_iterator I = CalledFunc->arg_begin(),
+                              E = CalledFunc->arg_end();
+       I != E; ++I) {
+    unsigned Align = I->getType()->isPointerTy() ? I->getParamAlignment() : 0;
+    if (Align && !I->hasByValOrInAllocaAttr() && !I->hasNUses(0)) {
+      if (!DTCalculated) {
+        DT.recalculate(const_cast<Function&>(*CS.getInstruction()->getParent()
+                                               ->getParent()));
+        DTCalculated = true;
+      }
+
+      // If we can already prove the asserted alignment in the context of the
+      // caller, then don't bother inserting the assumption.
+      Value *Arg = CS.getArgument(I->getArgNo());
+      if (getKnownAlignment(Arg, IFI.DL,
+                            &IFI.ACT->getAssumptionCache(*CalledFunc),
+                            CS.getInstruction(), &DT) >= Align)
+        continue;
+
+      IRBuilder<>(CS.getInstruction()).CreateAlignmentAssumption(*IFI.DL, Arg,
+                                                                 Align);
+    }
+  }
+}
+
 /// UpdateCallGraphAfterInlining - Once we have cloned code over from a callee
 /// into the caller, update the specified callgraph to reflect the changes we
 /// made.  Note that it's possible that not all code was copied over, so only
@@ -327,31 +726,19 @@ static void UpdateCallGraphAfterInlining(CallSite CS,
 static void HandleByValArgumentInit(Value *Dst, Value *Src, Module *M,
                                     BasicBlock *InsertBlock,
                                     InlineFunctionInfo &IFI) {
-  LLVMContext &Context = Src->getContext();
-  Type *VoidPtrTy = Type::getInt8PtrTy(Context);
   Type *AggTy = cast<PointerType>(Src->getType())->getElementType();
-  Type *Tys[3] = { VoidPtrTy, VoidPtrTy, Type::getInt64Ty(Context) };
-  Function *MemCpyFn = Intrinsic::getDeclaration(M, Intrinsic::memcpy, Tys);
-  IRBuilder<> builder(InsertBlock->begin());
-  Value *DstCast = builder.CreateBitCast(Dst, VoidPtrTy, "tmp");
-  Value *SrcCast = builder.CreateBitCast(Src, VoidPtrTy, "tmp");
+  IRBuilder<> Builder(InsertBlock->begin());
 
   Value *Size;
   if (IFI.DL == nullptr)
     Size = ConstantExpr::getSizeOf(AggTy);
   else
-    Size = ConstantInt::get(Type::getInt64Ty(Context),
-                            IFI.DL->getTypeStoreSize(AggTy));
+    Size = Builder.getInt64(IFI.DL->getTypeStoreSize(AggTy));
 
   // Always generate a memcpy of alignment 1 here because we don't know
   // the alignment of the src pointer.  Other optimizations can infer
   // better alignment.
-  Value *CallArgs[] = {
-    DstCast, SrcCast, Size,
-    ConstantInt::get(Type::getInt32Ty(Context), 1),
-    ConstantInt::getFalse(Context) // isVolatile
-  };
-  builder.CreateCall(MemCpyFn, CallArgs);
+  Builder.CreateMemCpy(Dst, Src, Size, /*Align=*/1);
 }
 
 /// HandleByValArgument - When inlining a call site that has a byval argument,
@@ -363,6 +750,8 @@ static Value *HandleByValArgument(Value *Arg, Instruction *TheCall,
   PointerType *ArgTy = cast<PointerType>(Arg->getType());
   Type *AggTy = ArgTy->getElementType();
 
+  Function *Caller = TheCall->getParent()->getParent();
+
   // If the called function is readonly, then it could not mutate the caller's
   // copy of the byval'd memory.  In this case, it is safe to elide the copy and
   // temporary.
@@ -375,8 +764,9 @@ static Value *HandleByValArgument(Value *Arg, Instruction *TheCall,
 
     // If the pointer is already known to be sufficiently aligned, or if we can
     // round it up to a larger alignment, then we don't need a temporary.
-    if (getOrEnforceKnownAlignment(Arg, ByValAlignment,
-                                   IFI.DL) >= ByValAlignment)
+    if (getOrEnforceKnownAlignment(Arg, ByValAlignment, IFI.DL,
+                                   &IFI.ACT->getAssumptionCache(*Caller),
+                                   TheCall) >= ByValAlignment)
       return Arg;
     
     // Otherwise, we have to make a memcpy to get a safe alignment.  This is bad
@@ -393,8 +783,6 @@ static Value *HandleByValArgument(Value *Arg, Instruction *TheCall,
   // pointer inside the callee).
   Align = std::max(Align, ByValAlignment);
   
-  Function *Caller = TheCall->getParent()->getParent(); 
-  
   Value *NewAlloca = new AllocaInst(AggTy, nullptr, Align, Arg->getName(), 
                                     &*Caller->begin()->begin());
   IFI.StaticAllocas.push_back(cast<AllocaInst>(NewAlloca));
@@ -472,47 +860,33 @@ static void fixupLineNumbers(Function *Fn, Function::iterator FI,
         // originates from the call location. This is important for
         // ((__always_inline__, __nodebug__)) functions which must use caller
         // location for all instructions in their function body.
+
+        // Don't update static allocas, as they may get moved later.
+        if (auto *AI = dyn_cast<AllocaInst>(BI))
+          if (isa<Constant>(AI->getArraySize()))
+            continue;
+
         BI->setDebugLoc(TheCallDL);
       } else {
         BI->setDebugLoc(updateInlinedAtInfo(DL, TheCallDL, BI->getContext()));
         if (DbgValueInst *DVI = dyn_cast<DbgValueInst>(BI)) {
           LLVMContext &Ctx = BI->getContext();
           MDNode *InlinedAt = BI->getDebugLoc().getInlinedAt(Ctx);
-          DVI->setOperand(2, createInlinedVariable(DVI->getVariable(), 
-                                                   InlinedAt, Ctx));
+          DVI->setOperand(2, MetadataAsValue::get(
+                                 Ctx, createInlinedVariable(DVI->getVariable(),
+                                                            InlinedAt, Ctx)));
+        } else if (DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(BI)) {
+          LLVMContext &Ctx = BI->getContext();
+          MDNode *InlinedAt = BI->getDebugLoc().getInlinedAt(Ctx);
+          DDI->setOperand(1, MetadataAsValue::get(
+                                 Ctx, createInlinedVariable(DDI->getVariable(),
+                                                            InlinedAt, Ctx)));
         }
       }
     }
   }
 }
 
-/// Returns a musttail call instruction if one immediately precedes the given
-/// return instruction with an optional bitcast instruction between them.
-static CallInst *getPrecedingMustTailCall(ReturnInst *RI) {
-  Instruction *Prev = RI->getPrevNode();
-  if (!Prev)
-    return nullptr;
-
-  if (Value *RV = RI->getReturnValue()) {
-    if (RV != Prev)
-      return nullptr;
-
-    // Look through the optional bitcast.
-    if (auto *BI = dyn_cast<BitCastInst>(Prev)) {
-      RV = BI->getOperand(0);
-      Prev = BI->getPrevNode();
-      if (!Prev || RV != Prev)
-        return nullptr;
-    }
-  }
-
-  if (auto *CI = dyn_cast<CallInst>(Prev)) {
-    if (CI->isMustTailCall())
-      return CI;
-  }
-  return nullptr;
-}
-
 /// InlineFunction - This function inlines the called function into the basic
 /// block of the caller.  This returns false if it is not possible to inline
 /// this call.  The program is still in a well defined state if this occurs
@@ -626,6 +1000,11 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
       VMap[I] = ActualArg;
     }
 
+    // Add alignment assumptions if necessary. We do this before the inlined
+    // instructions are actually cloned into the caller so that we can easily
+    // check what will be known at the start of the inlined code.
+    AddAlignmentAssumptions(CS, IFI);
+
     // We want the inliner to prune the code as it copies.  We would LOVE to
     // have no dead or constant instructions leftover after inlining occurs
     // (which can happen, e.g., because an argument was constant), but we'll be
@@ -648,6 +1027,17 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
 
     // Update inlined instructions' line number information.
     fixupLineNumbers(Caller, FirstNewBlock, TheCall);
+
+    // Clone existing noalias metadata if necessary.
+    CloneAliasScopeMetadata(CS, VMap);
+
+    // Add noalias metadata if necessary.
+    AddAliasScopeMetadata(CS, VMap, IFI.DL, IFI.AA);
+
+    // FIXME: We could register any cloned assumptions instead of clearing the
+    // whole function's cache.
+    if (IFI.ACT)
+      IFI.ACT->getAssumptionCache(*Caller).clear();
   }
 
   // If there are any alloca instructions in the block that used to be the entry
@@ -765,7 +1155,8 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
       for (ReturnInst *RI : Returns) {
         // Don't insert llvm.lifetime.end calls between a musttail call and a
         // return.  The return kills all local allocas.
-        if (InlinedMustTailCalls && getPrecedingMustTailCall(RI))
+        if (InlinedMustTailCalls &&
+            RI->getParent()->getTerminatingMustTailCall())
           continue;
         IRBuilder<>(RI).CreateLifetimeEnd(AI, AllocaSize);
       }
@@ -789,7 +1180,7 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
     for (ReturnInst *RI : Returns) {
       // Don't insert llvm.stackrestore calls between a musttail call and a
       // return.  The return will restore the stack pointer.
-      if (InlinedMustTailCalls && getPrecedingMustTailCall(RI))
+      if (InlinedMustTailCalls && RI->getParent()->getTerminatingMustTailCall())
         continue;
       IRBuilder<>(RI).CreateCall(StackRestore, SavedPtr);
     }
@@ -812,7 +1203,8 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
     // Handle the returns preceded by musttail calls separately.
     SmallVector<ReturnInst *, 8> NormalReturns;
     for (ReturnInst *RI : Returns) {
-      CallInst *ReturnedMustTail = getPrecedingMustTailCall(RI);
+      CallInst *ReturnedMustTail =
+          RI->getParent()->getTerminatingMustTailCall();
       if (!ReturnedMustTail) {
         NormalReturns.push_back(RI);
         continue;
@@ -1016,7 +1408,8 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
   // the entries are the same or undef).  If so, remove the PHI so it doesn't
   // block other optimizations.
   if (PHI) {
-    if (Value *V = SimplifyInstruction(PHI, IFI.DL)) {
+    if (Value *V = SimplifyInstruction(PHI, IFI.DL, nullptr, nullptr,
+                                       &IFI.ACT->getAssumptionCache(*Caller))) {
       PHI->replaceAllUsesWith(V);
       PHI->eraseFromParent();
     }
diff --git a/lib/Transforms/Utils/IntegerDivision.cpp b/lib/Transforms/Utils/IntegerDivision.cpp
index 9f91eeb79531..0ae746cc83db 100644
--- a/lib/Transforms/Utils/IntegerDivision.cpp
+++ b/lib/Transforms/Utils/IntegerDivision.cpp
@@ -398,11 +398,13 @@ bool llvm::expandRemainder(BinaryOperator *Rem) {
     Rem->dropAllReferences();
     Rem->eraseFromParent();
 
-    // If we didn't actually generate a udiv instruction, we're done
-    BinaryOperator *BO = dyn_cast<BinaryOperator>(Builder.GetInsertPoint());
-    if (!BO || BO->getOpcode() != Instruction::URem)
+    // If we didn't actually generate an urem instruction, we're done
+    // This happens for example if the input were constant. In this case the
+    // Builder insertion point was unchanged
+    if (Rem == Builder.GetInsertPoint())
       return true;
 
+    BinaryOperator *BO = dyn_cast<BinaryOperator>(Builder.GetInsertPoint());
     Rem = BO;
   }
 
@@ -456,11 +458,13 @@ bool llvm::expandDivision(BinaryOperator *Div) {
     Div->dropAllReferences();
     Div->eraseFromParent();
 
-    // If we didn't actually generate a udiv instruction, we're done
-    BinaryOperator *BO = dyn_cast<BinaryOperator>(Builder.GetInsertPoint());
-    if (!BO || BO->getOpcode() != Instruction::UDiv)
+    // If we didn't actually generate an udiv instruction, we're done
+    // This happens for example if the input were constant. In this case the
+    // Builder insertion point was unchanged
+    if (Div == Builder.GetInsertPoint())
       return true;
 
+    BinaryOperator *BO = dyn_cast<BinaryOperator>(Builder.GetInsertPoint());
     Div = BO;
   }
 
diff --git a/lib/Transforms/Utils/LCSSA.cpp b/lib/Transforms/Utils/LCSSA.cpp
index 51a3d9c1fced..3f9b702c5b9a 100644
--- a/lib/Transforms/Utils/LCSSA.cpp
+++ b/lib/Transforms/Utils/LCSSA.cpp
@@ -61,7 +61,7 @@ static bool isExitBlock(BasicBlock *BB,
 /// uses.
 static bool processInstruction(Loop &L, Instruction &Inst, DominatorTree &DT,
                                const SmallVectorImpl<BasicBlock *> &ExitBlocks,
-                               PredIteratorCache &PredCache) {
+                               PredIteratorCache &PredCache, LoopInfo *LI) {
   SmallVector<Use *, 16> UsesToRewrite;
 
   BasicBlock *InstBB = Inst.getParent();
@@ -94,6 +94,7 @@ static bool processInstruction(Loop &L, Instruction &Inst, DominatorTree &DT,
   DomTreeNode *DomNode = DT.getNode(DomBB);
 
   SmallVector<PHINode *, 16> AddedPHIs;
+  SmallVector<PHINode *, 8> PostProcessPHIs;
 
   SSAUpdater SSAUpdate;
   SSAUpdate.Initialize(Inst.getType(), Inst.getName());
@@ -131,6 +132,18 @@ static bool processInstruction(Loop &L, Instruction &Inst, DominatorTree &DT,
 
     // Remember that this phi makes the value alive in this block.
     SSAUpdate.AddAvailableValue(ExitBB, PN);
+
+    // LoopSimplify might fail to simplify some loops (e.g. when indirect
+    // branches are involved). In such situations, it might happen that an exit
+    // for Loop L1 is the header of a disjoint Loop L2. Thus, when we create
+    // PHIs in such an exit block, we are also inserting PHIs into L2's header.
+    // This could break LCSSA form for L2 because these inserted PHIs can also
+    // have uses outside of L2. Remember all PHIs in such situation as to
+    // revisit than later on. FIXME: Remove this if indirectbr support into
+    // LoopSimplify gets improved.
+    if (auto *OtherLoop = LI->getLoopFor(ExitBB))
+      if (!L.contains(OtherLoop))
+        PostProcessPHIs.push_back(PN);
   }
 
   // Rewrite all uses outside the loop in terms of the new PHIs we just
@@ -157,6 +170,25 @@ static bool processInstruction(Loop &L, Instruction &Inst, DominatorTree &DT,
     SSAUpdate.RewriteUse(*UsesToRewrite[i]);
   }
 
+  // Post process PHI instructions that were inserted into another disjoint loop
+  // and update their exits properly.
+  for (auto *I : PostProcessPHIs) {
+    if (I->use_empty())
+      continue;
+
+    BasicBlock *PHIBB = I->getParent();
+    Loop *OtherLoop = LI->getLoopFor(PHIBB);
+    SmallVector<BasicBlock *, 8> EBs;
+    OtherLoop->getExitBlocks(EBs);
+    if (EBs.empty())
+      continue;
+
+    // Recurse and re-process each PHI instruction. FIXME: we should really
+    // convert this entire thing to a worklist approach where we process a
+    // vector of instructions...
+    processInstruction(*OtherLoop, *I, DT, EBs, PredCache, LI);
+  }
+
   // Remove PHI nodes that did not have any uses rewritten.
   for (unsigned i = 0, e = AddedPHIs.size(); i != e; ++i) {
     if (AddedPHIs[i]->use_empty())
@@ -180,7 +212,8 @@ blockDominatesAnExit(BasicBlock *BB,
   return false;
 }
 
-bool llvm::formLCSSA(Loop &L, DominatorTree &DT, ScalarEvolution *SE) {
+bool llvm::formLCSSA(Loop &L, DominatorTree &DT, LoopInfo *LI,
+                     ScalarEvolution *SE) {
   bool Changed = false;
 
   // Get the set of exiting blocks.
@@ -212,7 +245,7 @@ bool llvm::formLCSSA(Loop &L, DominatorTree &DT, ScalarEvolution *SE) {
            !isa<PHINode>(I->user_back())))
         continue;
 
-      Changed |= processInstruction(L, *I, DT, ExitBlocks, PredCache);
+      Changed |= processInstruction(L, *I, DT, ExitBlocks, PredCache, LI);
     }
   }
 
@@ -228,15 +261,15 @@ bool llvm::formLCSSA(Loop &L, DominatorTree &DT, ScalarEvolution *SE) {
 }
 
 /// Process a loop nest depth first.
-bool llvm::formLCSSARecursively(Loop &L, DominatorTree &DT,
+bool llvm::formLCSSARecursively(Loop &L, DominatorTree &DT, LoopInfo *LI,
                                 ScalarEvolution *SE) {
   bool Changed = false;
 
   // Recurse depth-first through inner loops.
-  for (Loop::iterator LI = L.begin(), LE = L.end(); LI != LE; ++LI)
-    Changed |= formLCSSARecursively(**LI, DT, SE);
+  for (Loop::iterator I = L.begin(), E = L.end(); I != E; ++I)
+    Changed |= formLCSSARecursively(**I, DT, LI, SE);
 
-  Changed |= formLCSSA(L, DT, SE);
+  Changed |= formLCSSA(L, DT, LI, SE);
   return Changed;
 }
 
@@ -291,7 +324,7 @@ bool LCSSA::runOnFunction(Function &F) {
 
   // Simplify each loop nest in the function.
   for (LoopInfo::iterator I = LI->begin(), E = LI->end(); I != E; ++I)
-    Changed |= formLCSSARecursively(**I, *DT, SE);
+    Changed |= formLCSSARecursively(**I, *DT, LI, SE);
 
   return Changed;
 }
diff --git a/lib/Transforms/Utils/Local.cpp b/lib/Transforms/Utils/Local.cpp
index a5e443fcf46b..08a4b3f3b737 100644
--- a/lib/Transforms/Utils/Local.cpp
+++ b/lib/Transforms/Utils/Local.cpp
@@ -128,7 +128,7 @@ bool llvm::ConstantFoldTerminator(BasicBlock *BB, bool DeleteDeadConditions,
       // Check to see if this branch is going to the same place as the default
       // dest.  If so, eliminate it as an explicit compare.
       if (i.getCaseSuccessor() == DefaultDest) {
-        MDNode* MD = SI->getMetadata(LLVMContext::MD_prof);
+        MDNode *MD = SI->getMetadata(LLVMContext::MD_prof);
         unsigned NCases = SI->getNumCases();
         // Fold the case metadata into the default if there will be any branches
         // left, unless the metadata doesn't match the switch.
@@ -137,7 +137,8 @@ bool llvm::ConstantFoldTerminator(BasicBlock *BB, bool DeleteDeadConditions,
           SmallVector<uint32_t, 8> Weights;
           for (unsigned MD_i = 1, MD_e = MD->getNumOperands(); MD_i < MD_e;
                ++MD_i) {
-            ConstantInt* CI = dyn_cast<ConstantInt>(MD->getOperand(MD_i));
+            ConstantInt *CI =
+                mdconst::dyn_extract<ConstantInt>(MD->getOperand(MD_i));
             assert(CI);
             Weights.push_back(CI->getValue().getZExtValue());
           }
@@ -206,10 +207,12 @@ bool llvm::ConstantFoldTerminator(BasicBlock *BB, bool DeleteDeadConditions,
       BranchInst *NewBr = Builder.CreateCondBr(Cond,
                                                FirstCase.getCaseSuccessor(),
                                                SI->getDefaultDest());
-      MDNode* MD = SI->getMetadata(LLVMContext::MD_prof);
+      MDNode *MD = SI->getMetadata(LLVMContext::MD_prof);
       if (MD && MD->getNumOperands() == 3) {
-        ConstantInt *SICase = dyn_cast<ConstantInt>(MD->getOperand(2));
-        ConstantInt *SIDef = dyn_cast<ConstantInt>(MD->getOperand(1));
+        ConstantInt *SICase =
+            mdconst::dyn_extract<ConstantInt>(MD->getOperand(2));
+        ConstantInt *SIDef =
+            mdconst::dyn_extract<ConstantInt>(MD->getOperand(1));
         assert(SICase && SIDef);
         // The TrueWeight should be the weight for the single case of SI.
         NewBr->setMetadata(LLVMContext::MD_prof,
@@ -301,6 +304,14 @@ bool llvm::isInstructionTriviallyDead(Instruction *I,
     if (II->getIntrinsicID() == Intrinsic::lifetime_start ||
         II->getIntrinsicID() == Intrinsic::lifetime_end)
       return isa<UndefValue>(II->getArgOperand(1));
+
+    // Assumptions are dead if their condition is trivially true.
+    if (II->getIntrinsicID() == Intrinsic::assume) {
+      if (ConstantInt *Cond = dyn_cast<ConstantInt>(II->getArgOperand(0)))
+        return !Cond->isZero();
+
+      return false;
+    }
   }
 
   if (isAllocLikeFn(I, TLI)) return true;
@@ -384,7 +395,7 @@ bool llvm::RecursivelyDeleteDeadPHINode(PHINode *PN,
 
     // If we find an instruction more than once, we're on a cycle that
     // won't prove fruitful.
-    if (!Visited.insert(I)) {
+    if (!Visited.insert(I).second) {
       // Break the cycle and delete the instruction and its operands.
       I->replaceAllUsesWith(UndefValue::get(I->getType()));
       (void)RecursivelyDeleteTriviallyDeadInstructions(I, TLI);
@@ -931,13 +942,16 @@ static unsigned enforceKnownAlignment(Value *V, unsigned Align,
 /// and it is more than the alignment of the ultimate object, see if we can
 /// increase the alignment of the ultimate object, making this check succeed.
 unsigned llvm::getOrEnforceKnownAlignment(Value *V, unsigned PrefAlign,
-                                          const DataLayout *DL) {
+                                          const DataLayout *DL,
+                                          AssumptionCache *AC,
+                                          const Instruction *CxtI,
+                                          const DominatorTree *DT) {
   assert(V->getType()->isPointerTy() &&
          "getOrEnforceKnownAlignment expects a pointer!");
   unsigned BitWidth = DL ? DL->getPointerTypeSizeInBits(V->getType()) : 64;
 
   APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
-  computeKnownBits(V, KnownZero, KnownOne, DL);
+  computeKnownBits(V, KnownZero, KnownOne, DL, 0, AC, CxtI, DT);
   unsigned TrailZ = KnownZero.countTrailingOnes();
 
   // Avoid trouble with ridiculously large TrailZ values, such as
@@ -982,6 +996,7 @@ static bool LdStHasDebugValue(DIVariable &DIVar, Instruction *I) {
 bool llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
                                            StoreInst *SI, DIBuilder &Builder) {
   DIVariable DIVar(DDI->getVariable());
+  DIExpression DIExpr(DDI->getExpression());
   assert((!DIVar || DIVar.isVariable()) &&
          "Variable in DbgDeclareInst should be either null or a DIVariable.");
   if (!DIVar)
@@ -999,9 +1014,10 @@ bool llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
   if (SExtInst *SExt = dyn_cast<SExtInst>(SI->getOperand(0)))
     ExtendedArg = dyn_cast<Argument>(SExt->getOperand(0));
   if (ExtendedArg)
-    DbgVal = Builder.insertDbgValueIntrinsic(ExtendedArg, 0, DIVar, SI);
+    DbgVal = Builder.insertDbgValueIntrinsic(ExtendedArg, 0, DIVar, DIExpr, SI);
   else
-    DbgVal = Builder.insertDbgValueIntrinsic(SI->getOperand(0), 0, DIVar, SI);
+    DbgVal = Builder.insertDbgValueIntrinsic(SI->getOperand(0), 0, DIVar,
+                                             DIExpr, SI);
   DbgVal->setDebugLoc(DDI->getDebugLoc());
   return true;
 }
@@ -1011,6 +1027,7 @@ bool llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
 bool llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
                                            LoadInst *LI, DIBuilder &Builder) {
   DIVariable DIVar(DDI->getVariable());
+  DIExpression DIExpr(DDI->getExpression());
   assert((!DIVar || DIVar.isVariable()) &&
          "Variable in DbgDeclareInst should be either null or a DIVariable.");
   if (!DIVar)
@@ -1020,8 +1037,7 @@ bool llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
     return true;
 
   Instruction *DbgVal =
-    Builder.insertDbgValueIntrinsic(LI->getOperand(0), 0,
-                                    DIVar, LI);
+      Builder.insertDbgValueIntrinsic(LI->getOperand(0), 0, DIVar, DIExpr, LI);
   DbgVal->setDebugLoc(DDI->getDebugLoc());
   return true;
 }
@@ -1035,7 +1051,7 @@ static bool isArray(AllocaInst *AI) {
 /// LowerDbgDeclare - Lowers llvm.dbg.declare intrinsics into appropriate set
 /// of llvm.dbg.value intrinsics.
 bool llvm::LowerDbgDeclare(Function &F) {
-  DIBuilder DIB(*F.getParent());
+  DIBuilder DIB(*F.getParent(), /*AllowUnresolved*/ false);
   SmallVector<DbgDeclareInst *, 4> Dbgs;
   for (auto &FI : F)
     for (BasicBlock::iterator BI : FI)
@@ -1061,14 +1077,14 @@ bool llvm::LowerDbgDeclare(Function &F) {
         else if (LoadInst *LI = dyn_cast<LoadInst>(U))
           ConvertDebugDeclareToDebugValue(DDI, LI, DIB);
         else if (CallInst *CI = dyn_cast<CallInst>(U)) {
-	  // This is a call by-value or some other instruction that
-	  // takes a pointer to the variable. Insert a *value*
-	  // intrinsic that describes the alloca.
-	  auto DbgVal =
-	    DIB.insertDbgValueIntrinsic(AI, 0,
-					DIVariable(DDI->getVariable()), CI);
-	  DbgVal->setDebugLoc(DDI->getDebugLoc());
-	}
+          // This is a call by-value or some other instruction that
+          // takes a pointer to the variable. Insert a *value*
+          // intrinsic that describes the alloca.
+          auto DbgVal = DIB.insertDbgValueIntrinsic(
+              AI, 0, DIVariable(DDI->getVariable()),
+              DIExpression(DDI->getExpression()), CI);
+          DbgVal->setDebugLoc(DDI->getDebugLoc());
+        }
       DDI->eraseFromParent();
     }
   }
@@ -1078,10 +1094,11 @@ bool llvm::LowerDbgDeclare(Function &F) {
 /// FindAllocaDbgDeclare - Finds the llvm.dbg.declare intrinsic describing the
 /// alloca 'V', if any.
 DbgDeclareInst *llvm::FindAllocaDbgDeclare(Value *V) {
-  if (MDNode *DebugNode = MDNode::getIfExists(V->getContext(), V))
-    for (User *U : DebugNode->users())
-      if (DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(U))
-        return DDI;
+  if (auto *L = LocalAsMetadata::getIfExists(V))
+    if (auto *MDV = MetadataAsValue::getIfExists(V->getContext(), L))
+      for (User *U : MDV->users())
+        if (DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(U))
+          return DDI;
 
   return nullptr;
 }
@@ -1092,33 +1109,27 @@ bool llvm::replaceDbgDeclareForAlloca(AllocaInst *AI, Value *NewAllocaAddress,
   if (!DDI)
     return false;
   DIVariable DIVar(DDI->getVariable());
+  DIExpression DIExpr(DDI->getExpression());
   assert((!DIVar || DIVar.isVariable()) &&
          "Variable in DbgDeclareInst should be either null or a DIVariable.");
   if (!DIVar)
     return false;
 
-  // Create a copy of the original DIDescriptor for user variable, appending
+  // Create a copy of the original DIDescriptor for user variable, prepending
   // "deref" operation to a list of address elements, as new llvm.dbg.declare
   // will take a value storing address of the memory for variable, not
   // alloca itself.
-  Type *Int64Ty = Type::getInt64Ty(AI->getContext());
-  SmallVector<Value*, 4> NewDIVarAddress;
-  if (DIVar.hasComplexAddress()) {
-    for (unsigned i = 0, n = DIVar.getNumAddrElements(); i < n; ++i) {
-      NewDIVarAddress.push_back(
-          ConstantInt::get(Int64Ty, DIVar.getAddrElement(i)));
-    }
-  }
-  NewDIVarAddress.push_back(ConstantInt::get(Int64Ty, DIBuilder::OpDeref));
-  DIVariable NewDIVar = Builder.createComplexVariable(
-      DIVar.getTag(), DIVar.getContext(), DIVar.getName(),
-      DIVar.getFile(), DIVar.getLineNumber(), DIVar.getType(),
-      NewDIVarAddress, DIVar.getArgNumber());
+  SmallVector<int64_t, 4> NewDIExpr;
+  NewDIExpr.push_back(dwarf::DW_OP_deref);
+  if (DIExpr)
+    for (unsigned i = 0, n = DIExpr.getNumElements(); i < n; ++i)
+      NewDIExpr.push_back(DIExpr.getElement(i));
 
   // Insert llvm.dbg.declare in the same basic block as the original alloca,
   // and remove old llvm.dbg.declare.
   BasicBlock *BB = AI->getParent();
-  Builder.insertDeclare(NewAllocaAddress, NewDIVar, BB);
+  Builder.insertDeclare(NewAllocaAddress, DIVar,
+                        Builder.createExpression(NewDIExpr), BB);
   DDI->eraseFromParent();
   return true;
 }
@@ -1170,7 +1181,7 @@ static void changeToCall(InvokeInst *II) {
 }
 
 static bool markAliveBlocks(BasicBlock *BB,
-                            SmallPtrSet<BasicBlock*, 128> &Reachable) {
+                            SmallPtrSetImpl<BasicBlock*> &Reachable) {
 
   SmallVector<BasicBlock*, 128> Worklist;
   Worklist.push_back(BB);
@@ -1183,6 +1194,26 @@ static bool markAliveBlocks(BasicBlock *BB,
     // instructions into LLVM unreachable insts.  The instruction combining pass
     // canonicalizes unreachable insts into stores to null or undef.
     for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E;++BBI){
+      // Assumptions that are known to be false are equivalent to unreachable.
+      // Also, if the condition is undefined, then we make the choice most
+      // beneficial to the optimizer, and choose that to also be unreachable.
+      if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(BBI))
+        if (II->getIntrinsicID() == Intrinsic::assume) {
+          bool MakeUnreachable = false;
+          if (isa<UndefValue>(II->getArgOperand(0)))
+            MakeUnreachable = true;
+          else if (ConstantInt *Cond =
+                   dyn_cast<ConstantInt>(II->getArgOperand(0)))
+            MakeUnreachable = Cond->isZero();
+
+          if (MakeUnreachable) {
+            // Don't insert a call to llvm.trap right before the unreachable.
+            changeToUnreachable(BBI, false);
+            Changed = true;
+            break;
+          }
+        }
+
       if (CallInst *CI = dyn_cast<CallInst>(BBI)) {
         if (CI->doesNotReturn()) {
           // If we found a call to a no-return function, insert an unreachable
@@ -1237,7 +1268,7 @@ static bool markAliveBlocks(BasicBlock *BB,
 
     Changed |= ConstantFoldTerminator(BB, true);
     for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE; ++SI)
-      if (Reachable.insert(*SI))
+      if (Reachable.insert(*SI).second)
         Worklist.push_back(*SI);
   } while (!Worklist.empty());
   return Changed;
@@ -1277,3 +1308,43 @@ bool llvm::removeUnreachableBlocks(Function &F) {
 
   return true;
 }
+
+void llvm::combineMetadata(Instruction *K, const Instruction *J, ArrayRef<unsigned> KnownIDs) {
+  SmallVector<std::pair<unsigned, MDNode *>, 4> Metadata;
+  K->dropUnknownMetadata(KnownIDs);
+  K->getAllMetadataOtherThanDebugLoc(Metadata);
+  for (unsigned i = 0, n = Metadata.size(); i < n; ++i) {
+    unsigned Kind = Metadata[i].first;
+    MDNode *JMD = J->getMetadata(Kind);
+    MDNode *KMD = Metadata[i].second;
+
+    switch (Kind) {
+      default:
+        K->setMetadata(Kind, nullptr); // Remove unknown metadata
+        break;
+      case LLVMContext::MD_dbg:
+        llvm_unreachable("getAllMetadataOtherThanDebugLoc returned a MD_dbg");
+      case LLVMContext::MD_tbaa:
+        K->setMetadata(Kind, MDNode::getMostGenericTBAA(JMD, KMD));
+        break;
+      case LLVMContext::MD_alias_scope:
+      case LLVMContext::MD_noalias:
+        K->setMetadata(Kind, MDNode::intersect(JMD, KMD));
+        break;
+      case LLVMContext::MD_range:
+        K->setMetadata(Kind, MDNode::getMostGenericRange(JMD, KMD));
+        break;
+      case LLVMContext::MD_fpmath:
+        K->setMetadata(Kind, MDNode::getMostGenericFPMath(JMD, KMD));
+        break;
+      case LLVMContext::MD_invariant_load:
+        // Only set the !invariant.load if it is present in both instructions.
+        K->setMetadata(Kind, JMD);
+        break;
+      case LLVMContext::MD_nonnull:
+        // Only set the !nonnull if it is present in both instructions.
+        K->setMetadata(Kind, JMD);
+        break;
+    }
+  }
+}
diff --git a/lib/Transforms/Utils/LoopSimplify.cpp b/lib/Transforms/Utils/LoopSimplify.cpp
index ef422914b6b2..c832a4b36f50 100644
--- a/lib/Transforms/Utils/LoopSimplify.cpp
+++ b/lib/Transforms/Utils/LoopSimplify.cpp
@@ -44,6 +44,7 @@
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/AssumptionCache.h"
 #include "llvm/Analysis/DependenceAnalysis.h"
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/Analysis/LoopInfo.h"
@@ -173,8 +174,7 @@ static BasicBlock *rewriteLoopExitBlock(Loop *L, BasicBlock *Exit, Pass *PP) {
 
   if (Exit->isLandingPad()) {
     SmallVector<BasicBlock*, 2> NewBBs;
-    SplitLandingPadPredecessors(Exit, ArrayRef<BasicBlock*>(&LoopBlocks[0],
-                                                            LoopBlocks.size()),
+    SplitLandingPadPredecessors(Exit, LoopBlocks,
                                 ".loopexit", ".nonloopexit",
                                 PP, NewBBs);
     NewExitBB = NewBBs[0];
@@ -209,11 +209,12 @@ static void addBlockAndPredsToSet(BasicBlock *InputBB, BasicBlock *StopBlock,
 /// \brief The first part of loop-nestification is to find a PHI node that tells
 /// us how to partition the loops.
 static PHINode *findPHIToPartitionLoops(Loop *L, AliasAnalysis *AA,
-                                        DominatorTree *DT) {
+                                        DominatorTree *DT,
+                                        AssumptionCache *AC) {
   for (BasicBlock::iterator I = L->getHeader()->begin(); isa<PHINode>(I); ) {
     PHINode *PN = cast<PHINode>(I);
     ++I;
-    if (Value *V = SimplifyInstruction(PN, nullptr, nullptr, DT)) {
+    if (Value *V = SimplifyInstruction(PN, nullptr, nullptr, DT, AC)) {
       // This is a degenerate PHI already, don't modify it!
       PN->replaceAllUsesWith(V);
       if (AA) AA->deleteValue(PN);
@@ -252,7 +253,8 @@ static PHINode *findPHIToPartitionLoops(Loop *L, AliasAnalysis *AA,
 ///
 static Loop *separateNestedLoop(Loop *L, BasicBlock *Preheader,
                                 AliasAnalysis *AA, DominatorTree *DT,
-                                LoopInfo *LI, ScalarEvolution *SE, Pass *PP) {
+                                LoopInfo *LI, ScalarEvolution *SE, Pass *PP,
+                                AssumptionCache *AC) {
   // Don't try to separate loops without a preheader.
   if (!Preheader)
     return nullptr;
@@ -261,7 +263,7 @@ static Loop *separateNestedLoop(Loop *L, BasicBlock *Preheader,
   assert(!L->getHeader()->isLandingPad() &&
          "Can't insert backedge to landing pad");
 
-  PHINode *PN = findPHIToPartitionLoops(L, AA, DT);
+  PHINode *PN = findPHIToPartitionLoops(L, AA, DT, AC);
   if (!PN) return nullptr;  // No known way to partition.
 
   // Pull out all predecessors that have varying values in the loop.  This
@@ -474,8 +476,8 @@ static BasicBlock *insertUniqueBackedgeBlock(Loop *L, BasicBlock *Preheader,
 /// explicit if they accepted the analysis directly and then updated it.
 static bool simplifyOneLoop(Loop *L, SmallVectorImpl<Loop *> &Worklist,
                             AliasAnalysis *AA, DominatorTree *DT, LoopInfo *LI,
-                            ScalarEvolution *SE, Pass *PP,
-                            const DataLayout *DL) {
+                            ScalarEvolution *SE, Pass *PP, const DataLayout *DL,
+                            AssumptionCache *AC) {
   bool Changed = false;
 ReprocessLoop:
 
@@ -496,20 +498,19 @@ ReprocessLoop:
     }
 
     // Delete each unique out-of-loop (and thus dead) predecessor.
-    for (SmallPtrSet<BasicBlock*, 4>::iterator I = BadPreds.begin(),
-         E = BadPreds.end(); I != E; ++I) {
+    for (BasicBlock *P : BadPreds) {
 
       DEBUG(dbgs() << "LoopSimplify: Deleting edge from dead predecessor "
-                   << (*I)->getName() << "\n");
+                   << P->getName() << "\n");
 
       // Inform each successor of each dead pred.
-      for (succ_iterator SI = succ_begin(*I), SE = succ_end(*I); SI != SE; ++SI)
-        (*SI)->removePredecessor(*I);
+      for (succ_iterator SI = succ_begin(P), SE = succ_end(P); SI != SE; ++SI)
+        (*SI)->removePredecessor(P);
       // Zap the dead pred's terminator and replace it with unreachable.
-      TerminatorInst *TI = (*I)->getTerminator();
+      TerminatorInst *TI = P->getTerminator();
        TI->replaceAllUsesWith(UndefValue::get(TI->getType()));
-      (*I)->getTerminator()->eraseFromParent();
-      new UnreachableInst((*I)->getContext(), *I);
+      P->getTerminator()->eraseFromParent();
+      new UnreachableInst(P->getContext(), P);
       Changed = true;
     }
   }
@@ -582,7 +583,8 @@ ReprocessLoop:
     // this for loops with a giant number of backedges, just factor them into a
     // common backedge instead.
     if (L->getNumBackEdges() < 8) {
-      if (Loop *OuterL = separateNestedLoop(L, Preheader, AA, DT, LI, SE, PP)) {
+      if (Loop *OuterL =
+              separateNestedLoop(L, Preheader, AA, DT, LI, SE, PP, AC)) {
         ++NumNested;
         // Enqueue the outer loop as it should be processed next in our
         // depth-first nest walk.
@@ -612,7 +614,7 @@ ReprocessLoop:
   PHINode *PN;
   for (BasicBlock::iterator I = L->getHeader()->begin();
        (PN = dyn_cast<PHINode>(I++)); )
-    if (Value *V = SimplifyInstruction(PN, nullptr, nullptr, DT)) {
+    if (Value *V = SimplifyInstruction(PN, nullptr, nullptr, DT, AC)) {
       if (AA) AA->deleteValue(PN);
       if (SE) SE->forgetValue(PN);
       PN->replaceAllUsesWith(V);
@@ -712,7 +714,7 @@ ReprocessLoop:
 
 bool llvm::simplifyLoop(Loop *L, DominatorTree *DT, LoopInfo *LI, Pass *PP,
                         AliasAnalysis *AA, ScalarEvolution *SE,
-                        const DataLayout *DL) {
+                        const DataLayout *DL, AssumptionCache *AC) {
   bool Changed = false;
 
   // Worklist maintains our depth-first queue of loops in this nest to process.
@@ -730,7 +732,7 @@ bool llvm::simplifyLoop(Loop *L, DominatorTree *DT, LoopInfo *LI, Pass *PP,
 
   while (!Worklist.empty())
     Changed |= simplifyOneLoop(Worklist.pop_back_val(), Worklist, AA, DT, LI,
-                               SE, PP, DL);
+                               SE, PP, DL, AC);
 
   return Changed;
 }
@@ -749,10 +751,13 @@ namespace {
     LoopInfo *LI;
     ScalarEvolution *SE;
     const DataLayout *DL;
+    AssumptionCache *AC;
 
     bool runOnFunction(Function &F) override;
 
     void getAnalysisUsage(AnalysisUsage &AU) const override {
+      AU.addRequired<AssumptionCacheTracker>();
+
       // We need loop information to identify the loops...
       AU.addRequired<DominatorTreeWrapperPass>();
       AU.addPreserved<DominatorTreeWrapperPass>();
@@ -773,11 +778,12 @@ namespace {
 
 char LoopSimplify::ID = 0;
 INITIALIZE_PASS_BEGIN(LoopSimplify, "loop-simplify",
-                "Canonicalize natural loops", true, false)
+                "Canonicalize natural loops", false, false)
+INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(LoopInfo)
 INITIALIZE_PASS_END(LoopSimplify, "loop-simplify",
-                "Canonicalize natural loops", true, false)
+                "Canonicalize natural loops", false, false)
 
 // Publicly exposed interface to pass...
 char &llvm::LoopSimplifyID = LoopSimplify::ID;
@@ -794,10 +800,11 @@ bool LoopSimplify::runOnFunction(Function &F) {
   SE = getAnalysisIfAvailable<ScalarEvolution>();
   DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
   DL = DLP ? &DLP->getDataLayout() : nullptr;
+  AC = &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
 
   // Simplify each loop nest in the function.
   for (LoopInfo::iterator I = LI->begin(), E = LI->end(); I != E; ++I)
-    Changed |= simplifyLoop(*I, DT, LI, this, AA, SE, DL);
+    Changed |= simplifyLoop(*I, DT, LI, this, AA, SE, DL, AC);
 
   return Changed;
 }
diff --git a/lib/Transforms/Utils/LoopUnroll.cpp b/lib/Transforms/Utils/LoopUnroll.cpp
index ab1c25a75e26..57459206e528 100644
--- a/lib/Transforms/Utils/LoopUnroll.cpp
+++ b/lib/Transforms/Utils/LoopUnroll.cpp
@@ -19,6 +19,7 @@
 #include "llvm/Transforms/Utils/UnrollLoop.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/AssumptionCache.h"
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/Analysis/LoopIterator.h"
 #include "llvm/Analysis/LoopPass.h"
@@ -111,7 +112,7 @@ FoldBlockIntoPredecessor(BasicBlock *BB, LoopInfo* LI, LPPassManager *LPM,
   if (LPM) {
     if (ScalarEvolution *SE = LPM->getAnalysisIfAvailable<ScalarEvolution>()) {
       if (Loop *L = LI->getLoopFor(BB)) {
-        if (ForgottenLoops.insert(L))
+        if (ForgottenLoops.insert(L).second)
           SE->forgetLoop(L);
       }
     }
@@ -153,8 +154,8 @@ FoldBlockIntoPredecessor(BasicBlock *BB, LoopInfo* LI, LPPassManager *LPM,
 /// This utility preserves LoopInfo. If DominatorTree or ScalarEvolution are
 /// available from the Pass it must also preserve those analyses.
 bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount,
-                      bool AllowRuntime, unsigned TripMultiple,
-                      LoopInfo *LI, Pass *PP, LPPassManager *LPM) {
+                      bool AllowRuntime, unsigned TripMultiple, LoopInfo *LI,
+                      Pass *PP, LPPassManager *LPM, AssumptionCache *AC) {
   BasicBlock *Preheader = L->getLoopPreheader();
   if (!Preheader) {
     DEBUG(dbgs() << "  Can't unroll; loop preheader-insertion failed.\n");
@@ -222,11 +223,10 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount,
 
   // Notify ScalarEvolution that the loop will be substantially changed,
   // if not outright eliminated.
-  if (PP) {
-    ScalarEvolution *SE = PP->getAnalysisIfAvailable<ScalarEvolution>();
-    if (SE)
-      SE->forgetLoop(L);
-  }
+  ScalarEvolution *SE =
+      PP ? PP->getAnalysisIfAvailable<ScalarEvolution>() : nullptr;
+  if (SE)
+    SE->forgetLoop(L);
 
   // If we know the trip count, we know the multiple...
   unsigned BreakoutTrip = 0;
@@ -300,15 +300,45 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount,
 
   for (unsigned It = 1; It != Count; ++It) {
     std::vector<BasicBlock*> NewBlocks;
+    SmallDenseMap<const Loop *, Loop *, 4> NewLoops;
+    NewLoops[L] = L;
 
     for (LoopBlocksDFS::RPOIterator BB = BlockBegin; BB != BlockEnd; ++BB) {
       ValueToValueMapTy VMap;
       BasicBlock *New = CloneBasicBlock(*BB, VMap, "." + Twine(It));
       Header->getParent()->getBasicBlockList().push_back(New);
 
-      // Loop over all of the PHI nodes in the block, changing them to use the
-      // incoming values from the previous block.
+      // Tell LI about New.
+      if (*BB == Header) {
+        assert(LI->getLoopFor(*BB) == L && "Header should not be in a sub-loop");
+        L->addBasicBlockToLoop(New, LI->getBase());
+      } else {
+        // Figure out which loop New is in.
+        const Loop *OldLoop = LI->getLoopFor(*BB);
+        assert(OldLoop && "Should (at least) be in the loop being unrolled!");
+
+        Loop *&NewLoop = NewLoops[OldLoop];
+        if (!NewLoop) {
+          // Found a new sub-loop.
+          assert(*BB == OldLoop->getHeader() &&
+                 "Header should be first in RPO");
+
+          Loop *NewLoopParent = NewLoops.lookup(OldLoop->getParentLoop());
+          assert(NewLoopParent &&
+                 "Expected parent loop before sub-loop in RPO");
+          NewLoop = new Loop;
+          NewLoopParent->addChildLoop(NewLoop);
+
+          // Forget the old loop, since its inputs may have changed.
+          if (SE)
+            SE->forgetLoop(OldLoop);
+        }
+        NewLoop->addBasicBlockToLoop(New, LI->getBase());
+      }
+
       if (*BB == Header)
+        // Loop over all of the PHI nodes in the block, changing them to use
+        // the incoming values from the previous block.
         for (unsigned i = 0, e = OrigPHINode.size(); i != e; ++i) {
           PHINode *NewPHI = cast<PHINode>(VMap[OrigPHINode[i]]);
           Value *InVal = NewPHI->getIncomingValueForBlock(LatchBlock);
@@ -325,8 +355,6 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount,
            VI != VE; ++VI)
         LastValueMap[VI->first] = VI->second;
 
-      L->addBasicBlockToLoop(New, LI->getBase());
-
       // Add phi entries for newly created values to all exit blocks.
       for (succ_iterator SI = succ_begin(*BB), SE = succ_end(*BB);
            SI != SE; ++SI) {
@@ -442,6 +470,10 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount,
     }
   }
 
+  // FIXME: We could register any cloned assumptions instead of clearing the
+  // whole function's cache.
+  AC->clear();
+
   DominatorTree *DT = nullptr;
   if (PP) {
     // FIXME: Reconstruct dom info, because it is not preserved properly.
@@ -453,7 +485,6 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount,
     }
 
     // Simplify any new induction variables in the partially unrolled loop.
-    ScalarEvolution *SE = PP->getAnalysisIfAvailable<ScalarEvolution>();
     if (SE && !CompletelyUnroll) {
       SmallVector<WeakVH, 16> DeadInsts;
       simplifyLoopIVs(L, SE, LPM, DeadInsts);
@@ -502,8 +533,7 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount,
     if (OuterL) {
       DataLayoutPass *DLP = PP->getAnalysisIfAvailable<DataLayoutPass>();
       const DataLayout *DL = DLP ? &DLP->getDataLayout() : nullptr;
-      ScalarEvolution *SE = PP->getAnalysisIfAvailable<ScalarEvolution>();
-      simplifyLoop(OuterL, DT, LI, PP, /*AliasAnalysis*/ nullptr, SE, DL);
+      simplifyLoop(OuterL, DT, LI, PP, /*AliasAnalysis*/ nullptr, SE, DL, AC);
 
       // LCSSA must be performed on the outermost affected loop. The unrolled
       // loop's last loop latch is guaranteed to be in the outermost loop after
@@ -513,7 +543,7 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount,
         while (OuterL->getParentLoop() != LatchLoop)
           OuterL = OuterL->getParentLoop();
 
-      formLCSSARecursively(*OuterL, *DT, SE);
+      formLCSSARecursively(*OuterL, *DT, LI, SE);
     }
   }
 
diff --git a/lib/Transforms/Utils/LoopUnrollRuntime.cpp b/lib/Transforms/Utils/LoopUnrollRuntime.cpp
index a96c46ad63e0..f12cd61d463a 100644
--- a/lib/Transforms/Utils/LoopUnrollRuntime.cpp
+++ b/lib/Transforms/Utils/LoopUnrollRuntime.cpp
@@ -28,6 +28,7 @@
 #include "llvm/Analysis/ScalarEvolution.h"
 #include "llvm/Analysis/ScalarEvolutionExpander.h"
 #include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/Metadata.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
@@ -57,7 +58,7 @@ STATISTIC(NumRuntimeUnrolled,
 static void ConnectProlog(Loop *L, Value *TripCount, unsigned Count,
                           BasicBlock *LastPrologBB, BasicBlock *PrologEnd,
                           BasicBlock *OrigPH, BasicBlock *NewPH,
-                          ValueToValueMapTy &LVMap, Pass *P) {
+                          ValueToValueMapTy &VMap, Pass *P) {
   BasicBlock *Latch = L->getLoopLatch();
   assert(Latch && "Loop must have a latch");
 
@@ -86,7 +87,7 @@ static void ConnectProlog(Loop *L, Value *TripCount, unsigned Count,
       Value *V = PN->getIncomingValueForBlock(Latch);
       if (Instruction *I = dyn_cast<Instruction>(V)) {
         if (L->contains(I)) {
-          V = LVMap[I];
+          V = VMap[I];
         }
       }
       // Adding a value to the new PHI node from the last prolog block
@@ -127,76 +128,123 @@ static void ConnectProlog(Loop *L, Value *TripCount, unsigned Count,
 }
 
 /// Create a clone of the blocks in a loop and connect them together.
-/// This function doesn't create a clone of the loop structure.
+/// If UnrollProlog is true, loop structure will not be cloned, otherwise a new
+/// loop will be created including all cloned blocks, and the iterator of it
+/// switches to count NewIter down to 0.
 ///
-/// There are two value maps that are defined and used.  VMap is
-/// for the values in the current loop instance.  LVMap contains
-/// the values from the last loop instance.  We need the LVMap values
-/// to update the initial values for the current loop instance.
-///
-static void CloneLoopBlocks(Loop *L,
-                            bool FirstCopy,
-                            BasicBlock *InsertTop,
-                            BasicBlock *InsertBot,
+static void CloneLoopBlocks(Loop *L, Value *NewIter, const bool UnrollProlog,
+                            BasicBlock *InsertTop, BasicBlock *InsertBot,
                             std::vector<BasicBlock *> &NewBlocks,
-                            LoopBlocksDFS &LoopBlocks,
-                            ValueToValueMapTy &VMap,
-                            ValueToValueMapTy &LVMap,
+                            LoopBlocksDFS &LoopBlocks, ValueToValueMapTy &VMap,
                             LoopInfo *LI) {
-
   BasicBlock *Preheader = L->getLoopPreheader();
   BasicBlock *Header = L->getHeader();
   BasicBlock *Latch = L->getLoopLatch();
   Function *F = Header->getParent();
   LoopBlocksDFS::RPOIterator BlockBegin = LoopBlocks.beginRPO();
   LoopBlocksDFS::RPOIterator BlockEnd = LoopBlocks.endRPO();
+  Loop *NewLoop = 0;
+  Loop *ParentLoop = L->getParentLoop();
+  if (!UnrollProlog) {
+    NewLoop = new Loop();
+    if (ParentLoop)
+      ParentLoop->addChildLoop(NewLoop);
+    else
+      LI->addTopLevelLoop(NewLoop);
+  }
+
   // For each block in the original loop, create a new copy,
   // and update the value map with the newly created values.
   for (LoopBlocksDFS::RPOIterator BB = BlockBegin; BB != BlockEnd; ++BB) {
-    BasicBlock *NewBB = CloneBasicBlock(*BB, VMap, ".unr", F);
+    BasicBlock *NewBB = CloneBasicBlock(*BB, VMap, ".prol", F);
     NewBlocks.push_back(NewBB);
 
-    if (Loop *ParentLoop = L->getParentLoop())
+    if (NewLoop)
+      NewLoop->addBasicBlockToLoop(NewBB, LI->getBase());
+    else if (ParentLoop)
       ParentLoop->addBasicBlockToLoop(NewBB, LI->getBase());
 
     VMap[*BB] = NewBB;
     if (Header == *BB) {
       // For the first block, add a CFG connection to this newly
-      // created block
+      // created block.
       InsertTop->getTerminator()->setSuccessor(0, NewBB);
 
-      // Change the incoming values to the ones defined in the
-      // previously cloned loop.
-      for (BasicBlock::iterator I = Header->begin(); isa<PHINode>(I); ++I) {
-        PHINode *NewPHI = cast<PHINode>(VMap[I]);
-        if (FirstCopy) {
-          // We replace the first phi node with the value from the preheader
-          VMap[I] = NewPHI->getIncomingValueForBlock(Preheader);
-          NewBB->getInstList().erase(NewPHI);
-        } else {
-          // Update VMap with values from the previous block
-          unsigned idx = NewPHI->getBasicBlockIndex(Latch);
-          Value *InVal = NewPHI->getIncomingValue(idx);
-          if (Instruction *I = dyn_cast<Instruction>(InVal))
-            if (L->contains(I))
-              InVal = LVMap[InVal];
-          NewPHI->setIncomingValue(idx, InVal);
-          NewPHI->setIncomingBlock(idx, InsertTop);
-        }
-      }
     }
-
     if (Latch == *BB) {
+      // For the last block, if UnrollProlog is true, create a direct jump to
+      // InsertBot. If not, create a loop back to cloned head.
       VMap.erase((*BB)->getTerminator());
-      NewBB->getTerminator()->eraseFromParent();
-      BranchInst::Create(InsertBot, NewBB);
+      BasicBlock *FirstLoopBB = cast<BasicBlock>(VMap[Header]);
+      BranchInst *LatchBR = cast<BranchInst>(NewBB->getTerminator());
+      if (UnrollProlog) {
+        LatchBR->eraseFromParent();
+        BranchInst::Create(InsertBot, NewBB);
+      } else {
+        PHINode *NewIdx = PHINode::Create(NewIter->getType(), 2, "prol.iter",
+                                          FirstLoopBB->getFirstNonPHI());
+        IRBuilder<> Builder(LatchBR);
+        Value *IdxSub =
+            Builder.CreateSub(NewIdx, ConstantInt::get(NewIdx->getType(), 1),
+                              NewIdx->getName() + ".sub");
+        Value *IdxCmp =
+            Builder.CreateIsNotNull(IdxSub, NewIdx->getName() + ".cmp");
+        BranchInst::Create(FirstLoopBB, InsertBot, IdxCmp, NewBB);
+        NewIdx->addIncoming(NewIter, InsertTop);
+        NewIdx->addIncoming(IdxSub, NewBB);
+        LatchBR->eraseFromParent();
+      }
     }
   }
-  // LastValueMap is updated with the values for the current loop
-  // which are used the next time this function is called.
-  for (ValueToValueMapTy::iterator VI = VMap.begin(), VE = VMap.end();
-       VI != VE; ++VI) {
-    LVMap[VI->first] = VI->second;
+
+  // Change the incoming values to the ones defined in the preheader or
+  // cloned loop.
+  for (BasicBlock::iterator I = Header->begin(); isa<PHINode>(I); ++I) {
+    PHINode *NewPHI = cast<PHINode>(VMap[I]);
+    if (UnrollProlog) {
+      VMap[I] = NewPHI->getIncomingValueForBlock(Preheader);
+      cast<BasicBlock>(VMap[Header])->getInstList().erase(NewPHI);
+    } else {
+      unsigned idx = NewPHI->getBasicBlockIndex(Preheader);
+      NewPHI->setIncomingBlock(idx, InsertTop);
+      BasicBlock *NewLatch = cast<BasicBlock>(VMap[Latch]);
+      idx = NewPHI->getBasicBlockIndex(Latch);
+      Value *InVal = NewPHI->getIncomingValue(idx);
+      NewPHI->setIncomingBlock(idx, NewLatch);
+      if (VMap[InVal])
+        NewPHI->setIncomingValue(idx, VMap[InVal]);
+    }
+  }
+  if (NewLoop) {
+    // Add unroll disable metadata to disable future unrolling for this loop.
+    SmallVector<Metadata *, 4> MDs;
+    // Reserve first location for self reference to the LoopID metadata node.
+    MDs.push_back(nullptr);
+    MDNode *LoopID = NewLoop->getLoopID();
+    if (LoopID) {
+      // First remove any existing loop unrolling metadata.
+      for (unsigned i = 1, ie = LoopID->getNumOperands(); i < ie; ++i) {
+        bool IsUnrollMetadata = false;
+        MDNode *MD = dyn_cast<MDNode>(LoopID->getOperand(i));
+        if (MD) {
+          const MDString *S = dyn_cast<MDString>(MD->getOperand(0));
+          IsUnrollMetadata = S && S->getString().startswith("llvm.loop.unroll.");
+        }
+        if (!IsUnrollMetadata)
+          MDs.push_back(LoopID->getOperand(i));
+      }
+    }
+
+    LLVMContext &Context = NewLoop->getHeader()->getContext();
+    SmallVector<Metadata *, 1> DisableOperands;
+    DisableOperands.push_back(MDString::get(Context, "llvm.loop.unroll.disable"));
+    MDNode *DisableNode = MDNode::get(Context, DisableOperands);
+    MDs.push_back(DisableNode);
+
+    MDNode *NewLoopID = MDNode::get(Context, MDs);
+    // Set operand 0 to refer to the loop id itself.
+    NewLoopID->replaceOperandWith(0, NewLoopID);
+    NewLoop->setLoopID(NewLoopID);
   }
 }
 
@@ -212,18 +260,16 @@ static void CloneLoopBlocks(Loop *L,
 /// instruction in SimplifyCFG.cpp.  Then, the backend decides how code for
 /// the switch instruction is generated.
 ///
-///    extraiters = tripcount % loopfactor
-///    if (extraiters == 0) jump Loop:
-///    if (extraiters == loopfactor) jump L1
-///    if (extraiters == loopfactor-1) jump L2
-///    ...
-///    L1:  LoopBody;
-///    L2:  LoopBody;
-///    ...
-///    if tripcount < loopfactor jump End
-///    Loop:
-///    ...
-///    End:
+///        extraiters = tripcount % loopfactor
+///        if (extraiters == 0) jump Loop:
+///        else jump Prol
+/// Prol:  LoopBody;
+///        extraiters -= 1                 // Omitted if unroll factor is 2.
+///        if (extraiters != 0) jump Prol: // Omitted if unroll factor is 2.
+///        if (tripcount < loopfactor) jump End
+/// Loop:
+/// ...
+/// End:
 ///
 bool llvm::UnrollRuntimeLoopProlog(Loop *L, unsigned Count, LoopInfo *LI,
                                    LPPassManager *LPM) {
@@ -250,6 +296,10 @@ bool llvm::UnrollRuntimeLoopProlog(Loop *L, unsigned Count, LoopInfo *LI,
   if (isa<SCEVCouldNotCompute>(BECount) || !BECount->getType()->isIntegerTy())
     return false;
 
+  // If BECount is INT_MAX, we can't compute trip-count without overflow.
+  if (BECount->isAllOnesValue())
+    return false;
+
   // Add 1 since the backedge count doesn't include the first loop iteration
   const SCEV *TripCountSC =
     SE->getAddExpr(BECount, SE->getConstant(BECount->getType(), 1));
@@ -284,26 +334,21 @@ bool llvm::UnrollRuntimeLoopProlog(Loop *L, unsigned Count, LoopInfo *LI,
   IRBuilder<> B(PreHeaderBR);
   Value *ModVal = B.CreateAnd(TripCount, Count - 1, "xtraiter");
 
-  // Check if for no extra iterations, then jump to unrolled loop.  We have to
-  // check that the trip count computation didn't overflow when adding one to
-  // the backedge taken count.
+  // Check if for no extra iterations, then jump to cloned/unrolled loop.
+  // We have to check that the trip count computation didn't overflow when
+  // adding one to the backedge taken count.
   Value *LCmp = B.CreateIsNotNull(ModVal, "lcmp.mod");
   Value *OverflowCheck = B.CreateIsNull(TripCount, "lcmp.overflow");
   Value *BranchVal = B.CreateOr(OverflowCheck, LCmp, "lcmp.or");
 
-  // Branch to either the extra iterations or the unrolled loop
+  // Branch to either the extra iterations or the cloned/unrolled loop
   // We will fix up the true branch label when adding loop body copies
   BranchInst::Create(PEnd, PEnd, BranchVal, PreHeaderBR);
   assert(PreHeaderBR->isUnconditional() &&
          PreHeaderBR->getSuccessor(0) == PEnd &&
          "CFG edges in Preheader are not correct");
   PreHeaderBR->eraseFromParent();
-
-  ValueToValueMapTy LVMap;
   Function *F = Header->getParent();
-  // These variables are used to update the CFG links in each iteration
-  BasicBlock *CompareBB = nullptr;
-  BasicBlock *LastLoopBB = PH;
   // Get an ordered list of blocks in the loop to help with the ordering of the
   // cloned blocks in the prolog code
   LoopBlocksDFS LoopBlocks(L);
@@ -314,62 +359,39 @@ bool llvm::UnrollRuntimeLoopProlog(Loop *L, unsigned Count, LoopInfo *LI,
   // and generate a condition that branches to the copy depending on the
   // number of 'left over' iterations.
   //
-  for (unsigned leftOverIters = Count-1; leftOverIters > 0; --leftOverIters) {
-    std::vector<BasicBlock*> NewBlocks;
-    ValueToValueMapTy VMap;
-
-    // Clone all the basic blocks in the loop, but we don't clone the loop
-    // This function adds the appropriate CFG connections.
-    CloneLoopBlocks(L, (leftOverIters == Count-1), LastLoopBB, PEnd, NewBlocks,
-                    LoopBlocks, VMap, LVMap, LI);
-    LastLoopBB = cast<BasicBlock>(VMap[Latch]);
-
-    // Insert the cloned blocks into function just before the original loop
-    F->getBasicBlockList().splice(PEnd, F->getBasicBlockList(),
-                                  NewBlocks[0], F->end());
-
-    // Generate the code for the comparison which determines if the loop
-    // prolog code needs to be executed.
-    if (leftOverIters == Count-1) {
-      // There is no compare block for the fall-thru case when for the last
-      // left over iteration
-      CompareBB = NewBlocks[0];
-    } else {
-      // Create a new block for the comparison
-      BasicBlock *NewBB = BasicBlock::Create(CompareBB->getContext(), "unr.cmp",
-                                             F, CompareBB);
-      if (Loop *ParentLoop = L->getParentLoop()) {
-        // Add the new block to the parent loop, if needed
-        ParentLoop->addBasicBlockToLoop(NewBB, LI->getBase());
-      }
-
-      // The comparison w/ the extra iteration value and branch
-      Type *CountTy = TripCount->getType();
-      Value *BranchVal = new ICmpInst(*NewBB, ICmpInst::ICMP_EQ, ModVal,
-                                      ConstantInt::get(CountTy, leftOverIters),
-                                      "un.tmp");
-      // Branch to either the extra iterations or the unrolled loop
-      BranchInst::Create(NewBlocks[0], CompareBB,
-                         BranchVal, NewBB);
-      CompareBB = NewBB;
-      PH->getTerminator()->setSuccessor(0, NewBB);
-      VMap[NewPH] = CompareBB;
-    }
-
-    // Rewrite the cloned instruction operands to use the values
-    // created when the clone is created.
-    for (unsigned i = 0, e = NewBlocks.size(); i != e; ++i) {
-      for (BasicBlock::iterator I = NewBlocks[i]->begin(),
-             E = NewBlocks[i]->end(); I != E; ++I) {
-        RemapInstruction(I, VMap,
-                         RF_NoModuleLevelChanges|RF_IgnoreMissingEntries);
-      }
+  std::vector<BasicBlock *> NewBlocks;
+  ValueToValueMapTy VMap;
+
+  // If unroll count is 2 and we can't overflow in tripcount computation (which
+  // is BECount + 1), then we don't need a loop for prologue, and we can unroll
+  // it. We can be sure that we don't overflow only if tripcount is a constant.
+  bool UnrollPrologue = (Count == 2 && isa<ConstantInt>(TripCount));
+
+  // Clone all the basic blocks in the loop. If Count is 2, we don't clone
+  // the loop, otherwise we create a cloned loop to execute the extra
+  // iterations. This function adds the appropriate CFG connections.
+  CloneLoopBlocks(L, ModVal, UnrollPrologue, PH, PEnd, NewBlocks, LoopBlocks,
+                  VMap, LI);
+
+  // Insert the cloned blocks into function just before the original loop
+  F->getBasicBlockList().splice(PEnd, F->getBasicBlockList(), NewBlocks[0],
+                                F->end());
+
+  // Rewrite the cloned instruction operands to use the values
+  // created when the clone is created.
+  for (unsigned i = 0, e = NewBlocks.size(); i != e; ++i) {
+    for (BasicBlock::iterator I = NewBlocks[i]->begin(),
+                              E = NewBlocks[i]->end();
+         I != E; ++I) {
+      RemapInstruction(I, VMap,
+                       RF_NoModuleLevelChanges | RF_IgnoreMissingEntries);
     }
   }
 
   // Connect the prolog code to the original loop and update the
   // PHI functions.
-  ConnectProlog(L, TripCount, Count, LastLoopBB, PEnd, PH, NewPH, LVMap,
+  BasicBlock *LastLoopBB = cast<BasicBlock>(VMap[Latch]);
+  ConnectProlog(L, TripCount, Count, LastLoopBB, PEnd, PH, NewPH, VMap,
                 LPM->getAsPass());
   NumRuntimeUnrolled++;
   return true;
diff --git a/lib/Transforms/Utils/LowerSwitch.cpp b/lib/Transforms/Utils/LowerSwitch.cpp
index d6e5bb626805..35cd917330ab 100644
--- a/lib/Transforms/Utils/LowerSwitch.cpp
+++ b/lib/Transforms/Utils/LowerSwitch.cpp
@@ -131,18 +131,39 @@ static raw_ostream& operator<<(raw_ostream &O,
   return O << "]";
 }
 
-static void fixPhis(BasicBlock *Succ,
-                    BasicBlock *OrigBlock,
-                    BasicBlock *NewNode) {
-  for (BasicBlock::iterator I = Succ->begin(),
-                            E = Succ->getFirstNonPHI();
-       I != E; ++I) {
+// \brief Update the first occurrence of the "switch statement" BB in the PHI
+// node with the "new" BB. The other occurrences will:
+//
+// 1) Be updated by subsequent calls to this function.  Switch statements may
+// have more than one outcoming edge into the same BB if they all have the same
+// value. When the switch statement is converted these incoming edges are now
+// coming from multiple BBs.
+// 2) Removed if subsequent incoming values now share the same case, i.e.,
+// multiple outcome edges are condensed into one. This is necessary to keep the
+// number of phi values equal to the number of branches to SuccBB.
+static void fixPhis(BasicBlock *SuccBB, BasicBlock *OrigBB, BasicBlock *NewBB,
+                    unsigned NumMergedCases) {
+  for (BasicBlock::iterator I = SuccBB->begin(), IE = SuccBB->getFirstNonPHI();
+       I != IE; ++I) {
     PHINode *PN = cast<PHINode>(I);
 
-    for (unsigned I = 0, E = PN->getNumIncomingValues(); I != E; ++I) {
-      if (PN->getIncomingBlock(I) == OrigBlock)
-        PN->setIncomingBlock(I, NewNode);
+    // Only update the first occurence.
+    unsigned Idx = 0, E = PN->getNumIncomingValues();
+    unsigned LocalNumMergedCases = NumMergedCases;
+    for (; Idx != E; ++Idx) {
+      if (PN->getIncomingBlock(Idx) == OrigBB) {
+        PN->setIncomingBlock(Idx, NewBB);
+        break;
+      }
     }
+
+    // Remove additional occurences coming from condensed cases and keep the
+    // number of incoming values equal to the number of branches to SuccBB.
+    for (++Idx; LocalNumMergedCases > 0 && Idx < E; ++Idx)
+      if (PN->getIncomingBlock(Idx) == OrigBB) {
+        PN->removeIncomingValue(Idx);
+        LocalNumMergedCases--;
+      }
   }
 }
 
@@ -165,7 +186,11 @@ BasicBlock *LowerSwitch::switchConvert(CaseItr Begin, CaseItr End,
     // emitting the code that checks if the value actually falls in the range
     // because the bounds already tell us so.
     if (Begin->Low == LowerBound && Begin->High == UpperBound) {
-      fixPhis(Begin->BB, OrigBlock, Predecessor);
+      unsigned NumMergedCases = 0;
+      if (LowerBound && UpperBound)
+        NumMergedCases =
+            UpperBound->getSExtValue() - LowerBound->getSExtValue();
+      fixPhis(Begin->BB, OrigBlock, Predecessor, NumMergedCases);
       return Begin->BB;
     }
     return newLeafBlock(*Begin, Val, OrigBlock, Default);
diff --git a/lib/Transforms/Utils/Mem2Reg.cpp b/lib/Transforms/Utils/Mem2Reg.cpp
index 189caa7d145a..00cf4e6c01c8 100644
--- a/lib/Transforms/Utils/Mem2Reg.cpp
+++ b/lib/Transforms/Utils/Mem2Reg.cpp
@@ -14,6 +14,7 @@
 
 #include "llvm/Transforms/Scalar.h"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/AssumptionCache.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/Instructions.h"
@@ -38,6 +39,7 @@ namespace {
     bool runOnFunction(Function &F) override;
 
     void getAnalysisUsage(AnalysisUsage &AU) const override {
+      AU.addRequired<AssumptionCacheTracker>();
       AU.addRequired<DominatorTreeWrapperPass>();
       AU.setPreservesCFG();
       // This is a cluster of orthogonal Transforms
@@ -51,6 +53,7 @@ namespace {
 char PromotePass::ID = 0;
 INITIALIZE_PASS_BEGIN(PromotePass, "mem2reg", "Promote Memory to Register",
                 false, false)
+INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
 INITIALIZE_PASS_END(PromotePass, "mem2reg", "Promote Memory to Register",
                 false, false)
@@ -63,6 +66,8 @@ bool PromotePass::runOnFunction(Function &F) {
   bool Changed  = false;
 
   DominatorTree &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
+  AssumptionCache &AC =
+      getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
 
   while (1) {
     Allocas.clear();
@@ -76,7 +81,7 @@ bool PromotePass::runOnFunction(Function &F) {
 
     if (Allocas.empty()) break;
 
-    PromoteMemToReg(Allocas, DT);
+    PromoteMemToReg(Allocas, DT, nullptr, &AC);
     NumPromoted += Allocas.size();
     Changed = true;
   }
diff --git a/lib/Transforms/Utils/ModuleUtils.cpp b/lib/Transforms/Utils/ModuleUtils.cpp
index d9dbbca1c366..35c701eeedc9 100644
--- a/lib/Transforms/Utils/ModuleUtils.cpp
+++ b/lib/Transforms/Utils/ModuleUtils.cpp
@@ -78,7 +78,7 @@ void llvm::appendToGlobalDtors(Module &M, Function *F, int Priority) {
 }
 
 GlobalVariable *
-llvm::collectUsedGlobalVariables(Module &M, SmallPtrSet<GlobalValue *, 8> &Set,
+llvm::collectUsedGlobalVariables(Module &M, SmallPtrSetImpl<GlobalValue *> &Set,
                                  bool CompilerUsed) {
   const char *Name = CompilerUsed ? "llvm.compiler.used" : "llvm.used";
   GlobalVariable *GV = M.getGlobalVariable(Name);
diff --git a/lib/Transforms/Utils/PromoteMemoryToRegister.cpp b/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
index 06d73feb1cc8..dabadb794d4e 100644
--- a/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
+++ b/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
@@ -238,6 +238,9 @@ struct PromoteMem2Reg {
   /// An AliasSetTracker object to update.  If null, don't update it.
   AliasSetTracker *AST;
 
+  /// A cache of @llvm.assume intrinsics used by SimplifyInstruction.
+  AssumptionCache *AC;
+
   /// Reverse mapping of Allocas.
   DenseMap<AllocaInst *, unsigned> AllocaLookup;
 
@@ -279,9 +282,10 @@ struct PromoteMem2Reg {
 
 public:
   PromoteMem2Reg(ArrayRef<AllocaInst *> Allocas, DominatorTree &DT,
-                 AliasSetTracker *AST)
+                 AliasSetTracker *AST, AssumptionCache *AC)
       : Allocas(Allocas.begin(), Allocas.end()), DT(DT),
-        DIB(*DT.getRoot()->getParent()->getParent()), AST(AST) {}
+        DIB(*DT.getRoot()->getParent()->getParent(), /*AllowUnresolved*/ false),
+        AST(AST), AC(AC) {}
 
   void run();
 
@@ -302,8 +306,8 @@ private:
   void DetermineInsertionPoint(AllocaInst *AI, unsigned AllocaNum,
                                AllocaInfo &Info);
   void ComputeLiveInBlocks(AllocaInst *AI, AllocaInfo &Info,
-                           const SmallPtrSet<BasicBlock *, 32> &DefBlocks,
-                           SmallPtrSet<BasicBlock *, 32> &LiveInBlocks);
+                           const SmallPtrSetImpl<BasicBlock *> &DefBlocks,
+                           SmallPtrSetImpl<BasicBlock *> &LiveInBlocks);
   void RenamePass(BasicBlock *BB, BasicBlock *Pred,
                   RenamePassData::ValVector &IncVals,
                   std::vector<RenamePassData> &Worklist);
@@ -412,7 +416,8 @@ static bool rewriteSingleStoreAlloca(AllocaInst *AI, AllocaInfo &Info,
   // Record debuginfo for the store and remove the declaration's
   // debuginfo.
   if (DbgDeclareInst *DDI = Info.DbgDeclare) {
-    DIBuilder DIB(*AI->getParent()->getParent()->getParent());
+    DIBuilder DIB(*AI->getParent()->getParent()->getParent(),
+                  /*AllowUnresolved*/ false);
     ConvertDebugDeclareToDebugValue(DDI, Info.OnlyStore, DIB);
     DDI->eraseFromParent();
     LBI.deleteValue(DDI);
@@ -495,7 +500,8 @@ static void promoteSingleBlockAlloca(AllocaInst *AI, const AllocaInfo &Info,
     StoreInst *SI = cast<StoreInst>(AI->user_back());
     // Record debuginfo for the store before removing it.
     if (DbgDeclareInst *DDI = Info.DbgDeclare) {
-      DIBuilder DIB(*AI->getParent()->getParent()->getParent());
+      DIBuilder DIB(*AI->getParent()->getParent()->getParent(),
+                    /*AllowUnresolved*/ false);
       ConvertDebugDeclareToDebugValue(DDI, SI, DIB);
     }
     SI->eraseFromParent();
@@ -685,7 +691,7 @@ void PromoteMem2Reg::run() {
       PHINode *PN = I->second;
 
       // If this PHI node merges one value and/or undefs, get the value.
-      if (Value *V = SimplifyInstruction(PN, nullptr, nullptr, &DT)) {
+      if (Value *V = SimplifyInstruction(PN, nullptr, nullptr, &DT, AC)) {
         if (AST && PN->getType()->isPointerTy())
           AST->deleteValue(PN);
         PN->replaceAllUsesWith(V);
@@ -766,8 +772,8 @@ void PromoteMem2Reg::run() {
 /// inserted phi nodes would be dead).
 void PromoteMem2Reg::ComputeLiveInBlocks(
     AllocaInst *AI, AllocaInfo &Info,
-    const SmallPtrSet<BasicBlock *, 32> &DefBlocks,
-    SmallPtrSet<BasicBlock *, 32> &LiveInBlocks) {
+    const SmallPtrSetImpl<BasicBlock *> &DefBlocks,
+    SmallPtrSetImpl<BasicBlock *> &LiveInBlocks) {
 
   // To determine liveness, we must iterate through the predecessors of blocks
   // where the def is live.  Blocks are added to the worklist if we need to
@@ -816,7 +822,7 @@ void PromoteMem2Reg::ComputeLiveInBlocks(
 
     // The block really is live in here, insert it into the set.  If already in
     // the set, then it has already been processed.
-    if (!LiveInBlocks.insert(BB))
+    if (!LiveInBlocks.insert(BB).second)
       continue;
 
     // Since the value is live into BB, it is either defined in a predecessor or
@@ -857,10 +863,8 @@ void PromoteMem2Reg::DetermineInsertionPoint(AllocaInst *AI, unsigned AllocaNum,
                               less_second> IDFPriorityQueue;
   IDFPriorityQueue PQ;
 
-  for (SmallPtrSet<BasicBlock *, 32>::const_iterator I = DefBlocks.begin(),
-                                                     E = DefBlocks.end();
-       I != E; ++I) {
-    if (DomTreeNode *Node = DT.getNode(*I))
+  for (BasicBlock *BB : DefBlocks) {
+    if (DomTreeNode *Node = DT.getNode(BB))
       PQ.push(std::make_pair(Node, DomLevels[Node]));
   }
 
@@ -898,7 +902,7 @@ void PromoteMem2Reg::DetermineInsertionPoint(AllocaInst *AI, unsigned AllocaNum,
         if (SuccLevel > RootLevel)
           continue;
 
-        if (!Visited.insert(SuccNode))
+        if (!Visited.insert(SuccNode).second)
           continue;
 
         BasicBlock *SuccBB = SuccNode->getBlock();
@@ -1003,7 +1007,7 @@ NextIteration:
   }
 
   // Don't revisit blocks.
-  if (!Visited.insert(BB))
+  if (!Visited.insert(BB).second)
     return;
 
   for (BasicBlock::iterator II = BB->begin(); !isa<TerminatorInst>(II);) {
@@ -1060,17 +1064,17 @@ NextIteration:
   ++I;
 
   for (; I != E; ++I)
-    if (VisitedSuccs.insert(*I))
+    if (VisitedSuccs.insert(*I).second)
       Worklist.push_back(RenamePassData(*I, Pred, IncomingVals));
 
   goto NextIteration;
 }
 
 void llvm::PromoteMemToReg(ArrayRef<AllocaInst *> Allocas, DominatorTree &DT,
-                           AliasSetTracker *AST) {
+                           AliasSetTracker *AST, AssumptionCache *AC) {
   // If there is nothing to do, bail out...
   if (Allocas.empty())
     return;
 
-  PromoteMem2Reg(Allocas, DT, AST).run();
+  PromoteMem2Reg(Allocas, DT, AST, AC).run();
 }
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index 24bb63bb60a5..f6867c24ee58 100644
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -43,6 +43,8 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/Transforms/Utils/ValueMapper.h"
 #include <algorithm>
 #include <map>
 #include <set>
@@ -68,12 +70,24 @@ static cl::opt<bool> HoistCondStores(
     cl::desc("Hoist conditional stores if an unconditional store precedes"));
 
 STATISTIC(NumBitMaps, "Number of switch instructions turned into bitmaps");
+STATISTIC(NumLinearMaps, "Number of switch instructions turned into linear mapping");
 STATISTIC(NumLookupTables, "Number of switch instructions turned into lookup tables");
 STATISTIC(NumLookupTablesHoles, "Number of switch instructions turned into lookup tables (holes checked)");
+STATISTIC(NumTableCmpReuses, "Number of reused switch table lookup compares");
 STATISTIC(NumSinkCommons, "Number of common instructions sunk down to the end block");
 STATISTIC(NumSpeculations, "Number of speculative executed instructions");
 
 namespace {
+  // The first field contains the value that the switch produces when a certain
+  // case group is selected, and the second field is a vector containing the cases
+  // composing the case group.
+  typedef SmallVector<std::pair<Constant *, SmallVector<ConstantInt *, 4>>, 2>
+    SwitchCaseResultVectorTy;
+  // The first field contains the phi node that generates a result of the switch
+  // and the second field contains the value generated for a certain case in the switch
+  // for that PHI.
+  typedef SmallVector<std::pair<PHINode *, Constant *>, 4> SwitchCaseResultsTy;
+
   /// ValueEqualityComparisonCase - Represents a case of a switch.
   struct ValueEqualityComparisonCase {
     ConstantInt *Value;
@@ -92,7 +106,9 @@ namespace {
 
 class SimplifyCFGOpt {
   const TargetTransformInfo &TTI;
+  unsigned BonusInstThreshold;
   const DataLayout *const DL;
+  AssumptionCache *AC;
   Value *isValueEqualityComparison(TerminatorInst *TI);
   BasicBlock *GetValueEqualityComparisonCases(TerminatorInst *TI,
                                std::vector<ValueEqualityComparisonCase> &Cases);
@@ -111,8 +127,9 @@ class SimplifyCFGOpt {
   bool SimplifyCondBranch(BranchInst *BI, IRBuilder <>&Builder);
 
 public:
-  SimplifyCFGOpt(const TargetTransformInfo &TTI, const DataLayout *DL)
-      : TTI(TTI), DL(DL) {}
+  SimplifyCFGOpt(const TargetTransformInfo &TTI, unsigned BonusInstThreshold,
+                 const DataLayout *DL, AssumptionCache *AC)
+      : TTI(TTI), BonusInstThreshold(BonusInstThreshold), DL(DL), AC(AC) {}
   bool run(BasicBlock *BB);
 };
 }
@@ -256,7 +273,7 @@ static unsigned ComputeSpeculationCost(const User *I, const DataLayout *DL) {
 /// V plus its non-dominating operands.  If that cost is greater than
 /// CostRemaining, false is returned and CostRemaining is undefined.
 static bool DominatesMergePoint(Value *V, BasicBlock *BB,
-                                SmallPtrSet<Instruction*, 4> *AggressiveInsts,
+                                SmallPtrSetImpl<Instruction*> *AggressiveInsts,
                                 unsigned &CostRemaining,
                                 const DataLayout *DL) {
   Instruction *I = dyn_cast<Instruction>(V);
@@ -341,114 +358,177 @@ static ConstantInt *GetConstantInt(Value *V, const DataLayout *DL) {
   return nullptr;
 }
 
-/// GatherConstantCompares - Given a potentially 'or'd or 'and'd together
-/// collection of icmp eq/ne instructions that compare a value against a
-/// constant, return the value being compared, and stick the constant into the
-/// Values vector.
-static Value *
-GatherConstantCompares(Value *V, std::vector<ConstantInt*> &Vals, Value *&Extra,
-                       const DataLayout *DL, bool isEQ, unsigned &UsedICmps) {
-  Instruction *I = dyn_cast<Instruction>(V);
-  if (!I) return nullptr;
-
-  // If this is an icmp against a constant, handle this as one of the cases.
-  if (ICmpInst *ICI = dyn_cast<ICmpInst>(I)) {
-    if (ConstantInt *C = GetConstantInt(I->getOperand(1), DL)) {
-      Value *RHSVal;
-      ConstantInt *RHSC;
-
-      if (ICI->getPredicate() == (isEQ ? ICmpInst::ICMP_EQ:ICmpInst::ICMP_NE)) {
-        // (x & ~2^x) == y --> x == y || x == y|2^x
-        // This undoes a transformation done by instcombine to fuse 2 compares.
-        if (match(ICI->getOperand(0),
-                  m_And(m_Value(RHSVal), m_ConstantInt(RHSC)))) {
-          APInt Not = ~RHSC->getValue();
-          if (Not.isPowerOf2()) {
-            Vals.push_back(C);
-            Vals.push_back(
-                ConstantInt::get(C->getContext(), C->getValue() | Not));
-            UsedICmps++;
-            return RHSVal;
-          }
-        }
+namespace {
+
+/// Given a chain of or (||) or and (&&) comparison of a value against a
+/// constant, this will try to recover the information required for a switch
+/// structure.
+/// It will depth-first traverse the chain of comparison, seeking for patterns
+/// like %a == 12 or %a < 4 and combine them to produce a set of integer
+/// representing the different cases for the switch.
+/// Note that if the chain is composed of '||' it will build the set of elements
+/// that matches the comparisons (i.e. any of this value validate the chain)
+/// while for a chain of '&&' it will build the set elements that make the test
+/// fail.
+struct ConstantComparesGatherer {
+
+  Value *CompValue; /// Value found for the switch comparison
+  Value *Extra;     /// Extra clause to be checked before the switch
+  SmallVector<ConstantInt *, 8> Vals; /// Set of integers to match in switch
+  unsigned UsedICmps; /// Number of comparisons matched in the and/or chain
+
+  /// Construct and compute the result for the comparison instruction Cond
+  ConstantComparesGatherer(Instruction *Cond, const DataLayout *DL)
+      : CompValue(nullptr), Extra(nullptr), UsedICmps(0) {
+    gather(Cond, DL);
+  }
+
+  /// Prevent copy
+  ConstantComparesGatherer(const ConstantComparesGatherer &)
+      LLVM_DELETED_FUNCTION;
+  ConstantComparesGatherer &
+  operator=(const ConstantComparesGatherer &) LLVM_DELETED_FUNCTION;
+
+private:
 
-        UsedICmps++;
-        Vals.push_back(C);
-        return I->getOperand(0);
+  /// Try to set the current value used for the comparison, it succeeds only if
+  /// it wasn't set before or if the new value is the same as the old one
+  bool setValueOnce(Value *NewVal) {
+    if(CompValue && CompValue != NewVal) return false;
+    CompValue = NewVal;
+    return (CompValue != nullptr);
+  }
+
+  /// Try to match Instruction "I" as a comparison against a constant and
+  /// populates the array Vals with the set of values that match (or do not
+  /// match depending on isEQ).
+  /// Return false on failure. On success, the Value the comparison matched
+  /// against is placed in CompValue.
+  /// If CompValue is already set, the function is expected to fail if a match
+  /// is found but the value compared to is different.
+  bool matchInstruction(Instruction *I, const DataLayout *DL, bool isEQ) {
+    // If this is an icmp against a constant, handle this as one of the cases.
+    ICmpInst *ICI;
+    ConstantInt *C;
+    if (!((ICI = dyn_cast<ICmpInst>(I)) &&
+             (C = GetConstantInt(I->getOperand(1), DL)))) {
+      return false;
+    }
+
+    Value *RHSVal;
+    ConstantInt *RHSC;
+
+    // Pattern match a special case
+    // (x & ~2^x) == y --> x == y || x == y|2^x
+    // This undoes a transformation done by instcombine to fuse 2 compares.
+    if (ICI->getPredicate() == (isEQ ? ICmpInst::ICMP_EQ:ICmpInst::ICMP_NE)) {
+      if (match(ICI->getOperand(0),
+                m_And(m_Value(RHSVal), m_ConstantInt(RHSC)))) {
+        APInt Not = ~RHSC->getValue();
+        if (Not.isPowerOf2()) {
+          // If we already have a value for the switch, it has to match!
+          if(!setValueOnce(RHSVal))
+            return false;
+
+          Vals.push_back(C);
+          Vals.push_back(ConstantInt::get(C->getContext(),
+                                          C->getValue() | Not));
+          UsedICmps++;
+          return true;
+        }
       }
 
-      // If we have "x ult 3" comparison, for example, then we can add 0,1,2 to
-      // the set.
-      ConstantRange Span =
-        ConstantRange::makeICmpRegion(ICI->getPredicate(), C->getValue());
-
-      // Shift the range if the compare is fed by an add. This is the range
-      // compare idiom as emitted by instcombine.
-      bool hasAdd =
-          match(I->getOperand(0), m_Add(m_Value(RHSVal), m_ConstantInt(RHSC)));
-      if (hasAdd)
-        Span = Span.subtract(RHSC->getValue());
-
-      // If this is an and/!= check then we want to optimize "x ugt 2" into
-      // x != 0 && x != 1.
-      if (!isEQ)
-        Span = Span.inverse();
-
-      // If there are a ton of values, we don't want to make a ginormous switch.
-      if (Span.getSetSize().ugt(8) || Span.isEmptySet())
-        return nullptr;
-
-      for (APInt Tmp = Span.getLower(); Tmp != Span.getUpper(); ++Tmp)
-        Vals.push_back(ConstantInt::get(V->getContext(), Tmp));
+      // If we already have a value for the switch, it has to match!
+      if(!setValueOnce(ICI->getOperand(0)))
+        return false;
+
       UsedICmps++;
-      return hasAdd ? RHSVal : I->getOperand(0);
+      Vals.push_back(C);
+      return ICI->getOperand(0);
     }
-    return nullptr;
-  }
 
-  // Otherwise, we can only handle an | or &, depending on isEQ.
-  if (I->getOpcode() != (isEQ ? Instruction::Or : Instruction::And))
-    return nullptr;
+    // If we have "x ult 3", for example, then we can add 0,1,2 to the set.
+    ConstantRange Span = ConstantRange::makeICmpRegion(ICI->getPredicate(),
+                                                       C->getValue());
 
-  unsigned NumValsBeforeLHS = Vals.size();
-  unsigned UsedICmpsBeforeLHS = UsedICmps;
-  if (Value *LHS = GatherConstantCompares(I->getOperand(0), Vals, Extra, DL,
-                                          isEQ, UsedICmps)) {
-    unsigned NumVals = Vals.size();
-    unsigned UsedICmpsBeforeRHS = UsedICmps;
-    if (Value *RHS = GatherConstantCompares(I->getOperand(1), Vals, Extra, DL,
-                                            isEQ, UsedICmps)) {
-      if (LHS == RHS)
-        return LHS;
-      Vals.resize(NumVals);
-      UsedICmps = UsedICmpsBeforeRHS;
+    // Shift the range if the compare is fed by an add. This is the range
+    // compare idiom as emitted by instcombine.
+    Value *CandidateVal = I->getOperand(0);
+    if(match(I->getOperand(0), m_Add(m_Value(RHSVal), m_ConstantInt(RHSC)))) {
+      Span = Span.subtract(RHSC->getValue());
+      CandidateVal = RHSVal;
     }
 
-    // The RHS of the or/and can't be folded in and we haven't used "Extra" yet,
-    // set it and return success.
-    if (Extra == nullptr || Extra == I->getOperand(1)) {
-      Extra = I->getOperand(1);
-      return LHS;
+    // If this is an and/!= check, then we are looking to build the set of
+    // value that *don't* pass the and chain. I.e. to turn "x ugt 2" into
+    // x != 0 && x != 1.
+    if (!isEQ)
+      Span = Span.inverse();
+
+    // If there are a ton of values, we don't want to make a ginormous switch.
+    if (Span.getSetSize().ugt(8) || Span.isEmptySet()) {
+      return false;
     }
 
-    Vals.resize(NumValsBeforeLHS);
-    UsedICmps = UsedICmpsBeforeLHS;
-    return nullptr;
+    // If we already have a value for the switch, it has to match!
+    if(!setValueOnce(CandidateVal))
+      return false;
+
+    // Add all values from the range to the set
+    for (APInt Tmp = Span.getLower(); Tmp != Span.getUpper(); ++Tmp)
+      Vals.push_back(ConstantInt::get(I->getContext(), Tmp));
+
+    UsedICmps++;
+    return true;
+
   }
 
-  // If the LHS can't be folded in, but Extra is available and RHS can, try to
-  // use LHS as Extra.
-  if (Extra == nullptr || Extra == I->getOperand(0)) {
-    Value *OldExtra = Extra;
-    Extra = I->getOperand(0);
-    if (Value *RHS = GatherConstantCompares(I->getOperand(1), Vals, Extra, DL,
-                                            isEQ, UsedICmps))
-      return RHS;
-    assert(Vals.size() == NumValsBeforeLHS);
-    Extra = OldExtra;
+  /// gather - Given a potentially 'or'd or 'and'd together collection of icmp
+  /// eq/ne/lt/gt instructions that compare a value against a constant, extract
+  /// the value being compared, and stick the list constants into the Vals
+  /// vector.
+  /// One "Extra" case is allowed to differ from the other.
+  void gather(Value *V, const DataLayout *DL) {
+    Instruction *I = dyn_cast<Instruction>(V);
+    bool isEQ = (I->getOpcode() == Instruction::Or);
+
+    // Keep a stack (SmallVector for efficiency) for depth-first traversal
+    SmallVector<Value *, 8> DFT;
+
+    // Initialize
+    DFT.push_back(V);
+
+    while(!DFT.empty()) {
+      V = DFT.pop_back_val();
+
+      if (Instruction *I = dyn_cast<Instruction>(V)) {
+        // If it is a || (or && depending on isEQ), process the operands.
+        if (I->getOpcode() == (isEQ ? Instruction::Or : Instruction::And)) {
+          DFT.push_back(I->getOperand(1));
+          DFT.push_back(I->getOperand(0));
+          continue;
+        }
+
+        // Try to match the current instruction
+        if (matchInstruction(I, DL, isEQ))
+          // Match succeed, continue the loop
+          continue;
+      }
+
+      // One element of the sequence of || (or &&) could not be match as a
+      // comparison against the same value as the others.
+      // We allow only one "Extra" case to be checked before the switch
+      if (!Extra) {
+        Extra = V;
+        continue;
+      }
+      // Failed to parse a proper sequence, abort now
+      CompValue = nullptr;
+      break;
+    }
   }
+};
 
-  return nullptr;
 }
 
 static void EraseTerminatorInstAndDCECond(TerminatorInst *TI) {
@@ -628,13 +708,12 @@ SimplifyEqualityComparisonWithOnlyPredecessor(TerminatorInst *TI,
 
     // Collect branch weights into a vector.
     SmallVector<uint32_t, 8> Weights;
-    MDNode* MD = SI->getMetadata(LLVMContext::MD_prof);
+    MDNode *MD = SI->getMetadata(LLVMContext::MD_prof);
     bool HasWeight = MD && (MD->getNumOperands() == 2 + SI->getNumCases());
     if (HasWeight)
       for (unsigned MD_i = 1, MD_e = MD->getNumOperands(); MD_i < MD_e;
            ++MD_i) {
-        ConstantInt* CI = dyn_cast<ConstantInt>(MD->getOperand(MD_i));
-        assert(CI);
+        ConstantInt *CI = mdconst::extract<ConstantInt>(MD->getOperand(MD_i));
         Weights.push_back(CI->getValue().getZExtValue());
       }
     for (SwitchInst::CaseIt i = SI->case_end(), e = SI->case_begin(); i != e;) {
@@ -723,7 +802,7 @@ static int ConstantIntSortPredicate(ConstantInt *const *P1,
 }
 
 static inline bool HasBranchWeights(const Instruction* I) {
-  MDNode* ProfMD = I->getMetadata(LLVMContext::MD_prof);
+  MDNode *ProfMD = I->getMetadata(LLVMContext::MD_prof);
   if (ProfMD && ProfMD->getOperand(0))
     if (MDString* MDS = dyn_cast<MDString>(ProfMD->getOperand(0)))
       return MDS->getString().equals("branch_weights");
@@ -736,10 +815,10 @@ static inline bool HasBranchWeights(const Instruction* I) {
 /// metadata.
 static void GetBranchWeights(TerminatorInst *TI,
                              SmallVectorImpl<uint64_t> &Weights) {
-  MDNode* MD = TI->getMetadata(LLVMContext::MD_prof);
+  MDNode *MD = TI->getMetadata(LLVMContext::MD_prof);
   assert(MD);
   for (unsigned i = 1, e = MD->getNumOperands(); i < e; ++i) {
-    ConstantInt *CI = cast<ConstantInt>(MD->getOperand(i));
+    ConstantInt *CI = mdconst::extract<ConstantInt>(MD->getOperand(i));
     Weights.push_back(CI->getValue().getZExtValue());
   }
 
@@ -995,6 +1074,8 @@ static bool isSafeToHoistInvoke(BasicBlock *BB1, BasicBlock *BB2,
   return true;
 }
 
+static bool passingValueIsAlwaysUndefined(Value *V, Instruction *I);
+
 /// HoistThenElseCodeToIf - Given a conditional branch that goes to BB1 and
 /// BB2, hoist any common code in the two blocks up into the branch block.  The
 /// caller of this function guarantees that BI's block dominates BB1 and BB2.
@@ -1040,6 +1121,14 @@ static bool HoistThenElseCodeToIf(BranchInst *BI, const DataLayout *DL) {
     if (!I2->use_empty())
       I2->replaceAllUsesWith(I1);
     I1->intersectOptionalDataWith(I2);
+    unsigned KnownIDs[] = {
+      LLVMContext::MD_tbaa,
+      LLVMContext::MD_range,
+      LLVMContext::MD_fpmath,
+      LLVMContext::MD_invariant_load,
+      LLVMContext::MD_nonnull
+    };
+    combineMetadata(I1, I2, KnownIDs);
     I2->eraseFromParent();
     Changed = true;
 
@@ -1072,6 +1161,12 @@ HoistTerminator:
       if (BB1V == BB2V)
         continue;
 
+      // Check for passingValueIsAlwaysUndefined here because we would rather
+      // eliminate undefined control flow then converting it to a select.
+      if (passingValueIsAlwaysUndefined(BB1V, PN) ||
+          passingValueIsAlwaysUndefined(BB2V, PN))
+       return Changed;
+
       if (isa<ConstantExpr>(BB1V) && !isSafeToSpeculativelyExecute(BB1V, DL))
         return Changed;
       if (isa<ConstantExpr>(BB2V) && !isSafeToSpeculativelyExecute(BB2V, DL))
@@ -1149,14 +1244,13 @@ static bool SinkThenElseCodeToEnd(BranchInst *BI1) {
     return false;
 
   // Gather the PHI nodes in BBEnd.
-  std::map<Value*, std::pair<Value*, PHINode*> > MapValueFromBB1ToBB2;
+  SmallDenseMap<std::pair<Value *, Value *>, PHINode *> JointValueMap;
   Instruction *FirstNonPhiInBBEnd = nullptr;
-  for (BasicBlock::iterator I = BBEnd->begin(), E = BBEnd->end();
-       I != E; ++I) {
+  for (BasicBlock::iterator I = BBEnd->begin(), E = BBEnd->end(); I != E; ++I) {
     if (PHINode *PN = dyn_cast<PHINode>(I)) {
       Value *BB1V = PN->getIncomingValueForBlock(BB1);
       Value *BB2V = PN->getIncomingValueForBlock(BB2);
-      MapValueFromBB1ToBB2[BB1V] = std::make_pair(BB2V, PN);
+      JointValueMap[std::make_pair(BB1V, BB2V)] = PN;
     } else {
       FirstNonPhiInBBEnd = &*I;
       break;
@@ -1165,13 +1259,13 @@ static bool SinkThenElseCodeToEnd(BranchInst *BI1) {
   if (!FirstNonPhiInBBEnd)
     return false;
 
-
   // This does very trivial matching, with limited scanning, to find identical
   // instructions in the two blocks.  We scan backward for obviously identical
   // instructions in an identical order.
   BasicBlock::InstListType::reverse_iterator RI1 = BB1->getInstList().rbegin(),
-      RE1 = BB1->getInstList().rend(), RI2 = BB2->getInstList().rbegin(),
-      RE2 = BB2->getInstList().rend();
+                                             RE1 = BB1->getInstList().rend(),
+                                             RI2 = BB2->getInstList().rbegin(),
+                                             RE2 = BB2->getInstList().rend();
   // Skip debug info.
   while (RI1 != RE1 && isa<DbgInfoIntrinsic>(&*RI1)) ++RI1;
   if (RI1 == RE1)
@@ -1194,6 +1288,7 @@ static bool SinkThenElseCodeToEnd(BranchInst *BI1) {
       return Changed;
 
     Instruction *I1 = &*RI1, *I2 = &*RI2;
+    auto InstPair = std::make_pair(I1, I2);
     // I1 and I2 should have a single use in the same PHI node, and they
     // perform the same operation.
     // Cannot move control-flow-involving, volatile loads, vaarg, etc.
@@ -1204,11 +1299,11 @@ static bool SinkThenElseCodeToEnd(BranchInst *BI1) {
         I1->mayHaveSideEffects() || I2->mayHaveSideEffects() ||
         I1->mayReadOrWriteMemory() || I2->mayReadOrWriteMemory() ||
         !I1->hasOneUse() || !I2->hasOneUse() ||
-        MapValueFromBB1ToBB2.find(I1) == MapValueFromBB1ToBB2.end() ||
-        MapValueFromBB1ToBB2[I1].first != I2)
+        !JointValueMap.count(InstPair))
       return Changed;
 
     // Check whether we should swap the operands of ICmpInst.
+    // TODO: Add support of communativity.
     ICmpInst *ICmp1 = dyn_cast<ICmpInst>(I1), *ICmp2 = dyn_cast<ICmpInst>(I2);
     bool SwapOpnds = false;
     if (ICmp1 && ICmp2 &&
@@ -1229,16 +1324,13 @@ static bool SinkThenElseCodeToEnd(BranchInst *BI1) {
     // with a PHI node after sinking. We only handle the case where there is
     // a single pair of different operands.
     Value *DifferentOp1 = nullptr, *DifferentOp2 = nullptr;
-    unsigned Op1Idx = 0;
+    unsigned Op1Idx = ~0U;
     for (unsigned I = 0, E = I1->getNumOperands(); I != E; ++I) {
       if (I1->getOperand(I) == I2->getOperand(I))
         continue;
-      // Early exit if we have more-than one pair of different operands or
-      // the different operand is already in MapValueFromBB1ToBB2.
-      // Early exit if we need a PHI node to replace a constant.
-      if (DifferentOp1 ||
-          MapValueFromBB1ToBB2.find(I1->getOperand(I)) !=
-          MapValueFromBB1ToBB2.end() ||
+      // Early exit if we have more-than one pair of different operands or if
+      // we need a PHI node to replace a constant.
+      if (Op1Idx != ~0U ||
           isa<Constant>(I1->getOperand(I)) ||
           isa<Constant>(I2->getOperand(I))) {
         // If we can't sink the instructions, undo the swapping.
@@ -1251,24 +1343,27 @@ static bool SinkThenElseCodeToEnd(BranchInst *BI1) {
       DifferentOp2 = I2->getOperand(I);
     }
 
-    // We insert the pair of different operands to MapValueFromBB1ToBB2 and
-    // remove (I1, I2) from MapValueFromBB1ToBB2.
-    if (DifferentOp1) {
-      PHINode *NewPN = PHINode::Create(DifferentOp1->getType(), 2,
-                                       DifferentOp1->getName() + ".sink",
-                                       BBEnd->begin());
-      MapValueFromBB1ToBB2[DifferentOp1] = std::make_pair(DifferentOp2, NewPN);
+    DEBUG(dbgs() << "SINK common instructions " << *I1 << "\n");
+    DEBUG(dbgs() << "                         " << *I2 << "\n");
+
+    // We insert the pair of different operands to JointValueMap and
+    // remove (I1, I2) from JointValueMap.
+    if (Op1Idx != ~0U) {
+      auto &NewPN = JointValueMap[std::make_pair(DifferentOp1, DifferentOp2)];
+      if (!NewPN) {
+        NewPN =
+            PHINode::Create(DifferentOp1->getType(), 2,
+                            DifferentOp1->getName() + ".sink", BBEnd->begin());
+        NewPN->addIncoming(DifferentOp1, BB1);
+        NewPN->addIncoming(DifferentOp2, BB2);
+        DEBUG(dbgs() << "Create PHI node " << *NewPN << "\n";);
+      }
       // I1 should use NewPN instead of DifferentOp1.
       I1->setOperand(Op1Idx, NewPN);
-      NewPN->addIncoming(DifferentOp1, BB1);
-      NewPN->addIncoming(DifferentOp2, BB2);
-      DEBUG(dbgs() << "Create PHI node " << *NewPN << "\n";);
     }
-    PHINode *OldPN = MapValueFromBB1ToBB2[I1].second;
-    MapValueFromBB1ToBB2.erase(I1);
+    PHINode *OldPN = JointValueMap[InstPair];
+    JointValueMap.erase(InstPair);
 
-    DEBUG(dbgs() << "SINK common instructions " << *I1 << "\n";);
-    DEBUG(dbgs() << "                         " << *I2 << "\n";);
     // We need to update RE1 and RE2 if we are going to sink the first
     // instruction in the basic block down.
     bool UpdateRE1 = (I1 == BB1->begin()), UpdateRE2 = (I2 == BB2->begin());
@@ -1281,6 +1376,8 @@ static bool SinkThenElseCodeToEnd(BranchInst *BI1) {
     if (!I2->use_empty())
       I2->replaceAllUsesWith(I1);
     I1->intersectOptionalDataWith(I2);
+    // TODO: Use combineMetadata here to preserve what metadata we can
+    // (analogous to the hoisting case above).
     I2->eraseFromParent();
 
     if (UpdateRE1)
@@ -1486,6 +1583,11 @@ static bool SpeculativelyExecuteBB(BranchInst *BI, BasicBlock *ThenBB,
     if (ThenV == OrigV)
       continue;
 
+    // Don't convert to selects if we could remove undefined behavior instead.
+    if (passingValueIsAlwaysUndefined(OrigV, PN) ||
+        passingValueIsAlwaysUndefined(ThenV, PN))
+      return false;
+
     HaveRewritablePHIs = true;
     ConstantExpr *OrigCE = dyn_cast<ConstantExpr>(OrigV);
     ConstantExpr *ThenCE = dyn_cast<ConstantExpr>(ThenV);
@@ -1934,8 +2036,10 @@ static bool ExtractBranchMetadata(BranchInst *BI,
          "Looking for probabilities on unconditional branch?");
   MDNode *ProfileData = BI->getMetadata(LLVMContext::MD_prof);
   if (!ProfileData || ProfileData->getNumOperands() != 3) return false;
-  ConstantInt *CITrue = dyn_cast<ConstantInt>(ProfileData->getOperand(1));
-  ConstantInt *CIFalse = dyn_cast<ConstantInt>(ProfileData->getOperand(2));
+  ConstantInt *CITrue =
+      mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(1));
+  ConstantInt *CIFalse =
+      mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(2));
   if (!CITrue || !CIFalse) return false;
   ProbTrue = CITrue->getValue().getZExtValue();
   ProbFalse = CIFalse->getValue().getZExtValue();
@@ -1963,7 +2067,8 @@ static bool checkCSEInPredecessor(Instruction *Inst, BasicBlock *PB) {
 /// FoldBranchToCommonDest - If this basic block is simple enough, and if a
 /// predecessor branches to us and one of our successors, fold the block into
 /// the predecessor and use logical operations to pick the right destination.
-bool llvm::FoldBranchToCommonDest(BranchInst *BI, const DataLayout *DL) {
+bool llvm::FoldBranchToCommonDest(BranchInst *BI, const DataLayout *DL,
+                                  unsigned BonusInstThreshold) {
   BasicBlock *BB = BI->getParent();
 
   Instruction *Cond = nullptr;
@@ -2000,33 +2105,6 @@ bool llvm::FoldBranchToCommonDest(BranchInst *BI, const DataLayout *DL) {
       Cond->getParent() != BB || !Cond->hasOneUse())
   return false;
 
-  // Only allow this if the condition is a simple instruction that can be
-  // executed unconditionally.  It must be in the same block as the branch, and
-  // must be at the front of the block.
-  BasicBlock::iterator FrontIt = BB->front();
-
-  // Ignore dbg intrinsics.
-  while (isa<DbgInfoIntrinsic>(FrontIt)) ++FrontIt;
-
-  // Allow a single instruction to be hoisted in addition to the compare
-  // that feeds the branch.  We later ensure that any values that _it_ uses
-  // were also live in the predecessor, so that we don't unnecessarily create
-  // register pressure or inhibit out-of-order execution.
-  Instruction *BonusInst = nullptr;
-  if (&*FrontIt != Cond &&
-      FrontIt->hasOneUse() && FrontIt->user_back() == Cond &&
-      isSafeToSpeculativelyExecute(FrontIt, DL)) {
-    BonusInst = &*FrontIt;
-    ++FrontIt;
-
-    // Ignore dbg intrinsics.
-    while (isa<DbgInfoIntrinsic>(FrontIt)) ++FrontIt;
-  }
-
-  // Only a single bonus inst is allowed.
-  if (&*FrontIt != Cond)
-    return false;
-
   // Make sure the instruction after the condition is the cond branch.
   BasicBlock::iterator CondIt = Cond; ++CondIt;
 
@@ -2036,6 +2114,31 @@ bool llvm::FoldBranchToCommonDest(BranchInst *BI, const DataLayout *DL) {
   if (&*CondIt != BI)
     return false;
 
+  // Only allow this transformation if computing the condition doesn't involve
+  // too many instructions and these involved instructions can be executed
+  // unconditionally. We denote all involved instructions except the condition
+  // as "bonus instructions", and only allow this transformation when the
+  // number of the bonus instructions does not exceed a certain threshold.
+  unsigned NumBonusInsts = 0;
+  for (auto I = BB->begin(); Cond != I; ++I) {
+    // Ignore dbg intrinsics.
+    if (isa<DbgInfoIntrinsic>(I))
+      continue;
+    if (!I->hasOneUse() || !isSafeToSpeculativelyExecute(I, DL))
+      return false;
+    // I has only one use and can be executed unconditionally.
+    Instruction *User = dyn_cast<Instruction>(I->user_back());
+    if (User == nullptr || User->getParent() != BB)
+      return false;
+    // I is used in the same BB. Since BI uses Cond and doesn't have more slots
+    // to use any other instruction, User must be an instruction between next(I)
+    // and Cond.
+    ++NumBonusInsts;
+    // Early exits once we reach the limit.
+    if (NumBonusInsts > BonusInstThreshold)
+      return false;
+  }
+
   // Cond is known to be a compare or binary operator.  Check to make sure that
   // neither operand is a potentially-trapping constant expression.
   if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Cond->getOperand(0)))
@@ -2086,49 +2189,6 @@ bool llvm::FoldBranchToCommonDest(BranchInst *BI, const DataLayout *DL) {
         continue;
     }
 
-    // Ensure that any values used in the bonus instruction are also used
-    // by the terminator of the predecessor.  This means that those values
-    // must already have been resolved, so we won't be inhibiting the
-    // out-of-order core by speculating them earlier. We also allow
-    // instructions that are used by the terminator's condition because it
-    // exposes more merging opportunities.
-    bool UsedByBranch = (BonusInst && BonusInst->hasOneUse() &&
-                         BonusInst->user_back() == Cond);
-
-    if (BonusInst && !UsedByBranch) {
-      // Collect the values used by the bonus inst
-      SmallPtrSet<Value*, 4> UsedValues;
-      for (Instruction::op_iterator OI = BonusInst->op_begin(),
-           OE = BonusInst->op_end(); OI != OE; ++OI) {
-        Value *V = *OI;
-        if (!isa<Constant>(V) && !isa<Argument>(V))
-          UsedValues.insert(V);
-      }
-
-      SmallVector<std::pair<Value*, unsigned>, 4> Worklist;
-      Worklist.push_back(std::make_pair(PBI->getOperand(0), 0));
-
-      // Walk up to four levels back up the use-def chain of the predecessor's
-      // terminator to see if all those values were used.  The choice of four
-      // levels is arbitrary, to provide a compile-time-cost bound.
-      while (!Worklist.empty()) {
-        std::pair<Value*, unsigned> Pair = Worklist.back();
-        Worklist.pop_back();
-
-        if (Pair.second >= 4) continue;
-        UsedValues.erase(Pair.first);
-        if (UsedValues.empty()) break;
-
-        if (Instruction *I = dyn_cast<Instruction>(Pair.first)) {
-          for (Instruction::op_iterator OI = I->op_begin(), OE = I->op_end();
-               OI != OE; ++OI)
-            Worklist.push_back(std::make_pair(OI->get(), Pair.second+1));
-        }
-      }
-
-      if (!UsedValues.empty()) return false;
-    }
-
     DEBUG(dbgs() << "FOLDING BRANCH TO COMMON DEST:\n" << *PBI << *BB);
     IRBuilder<> Builder(PBI);
 
@@ -2148,30 +2208,41 @@ bool llvm::FoldBranchToCommonDest(BranchInst *BI, const DataLayout *DL) {
       PBI->swapSuccessors();
     }
 
-    // If we have a bonus inst, clone it into the predecessor block.
-    Instruction *NewBonus = nullptr;
-    if (BonusInst) {
-      NewBonus = BonusInst->clone();
+    // If we have bonus instructions, clone them into the predecessor block.
+    // Note that there may be mutliple predecessor blocks, so we cannot move
+    // bonus instructions to a predecessor block.
+    ValueToValueMapTy VMap; // maps original values to cloned values
+    // We already make sure Cond is the last instruction before BI. Therefore,
+    // every instructions before Cond other than DbgInfoIntrinsic are bonus
+    // instructions.
+    for (auto BonusInst = BB->begin(); Cond != BonusInst; ++BonusInst) {
+      if (isa<DbgInfoIntrinsic>(BonusInst))
+        continue;
+      Instruction *NewBonusInst = BonusInst->clone();
+      RemapInstruction(NewBonusInst, VMap,
+                       RF_NoModuleLevelChanges | RF_IgnoreMissingEntries);
+      VMap[BonusInst] = NewBonusInst;
 
       // If we moved a load, we cannot any longer claim any knowledge about
       // its potential value. The previous information might have been valid
       // only given the branch precondition.
       // For an analogous reason, we must also drop all the metadata whose
       // semantics we don't understand.
-      NewBonus->dropUnknownMetadata(LLVMContext::MD_dbg);
+      NewBonusInst->dropUnknownMetadata(LLVMContext::MD_dbg);
 
-      PredBlock->getInstList().insert(PBI, NewBonus);
-      NewBonus->takeName(BonusInst);
-      BonusInst->setName(BonusInst->getName()+".old");
+      PredBlock->getInstList().insert(PBI, NewBonusInst);
+      NewBonusInst->takeName(BonusInst);
+      BonusInst->setName(BonusInst->getName() + ".old");
     }
 
     // Clone Cond into the predecessor basic block, and or/and the
     // two conditions together.
     Instruction *New = Cond->clone();
-    if (BonusInst) New->replaceUsesOfWith(BonusInst, NewBonus);
+    RemapInstruction(New, VMap,
+                     RF_NoModuleLevelChanges | RF_IgnoreMissingEntries);
     PredBlock->getInstList().insert(PBI, New);
     New->takeName(Cond);
-    Cond->setName(New->getName()+".old");
+    Cond->setName(New->getName() + ".old");
 
     if (BI->isConditional()) {
       Instruction *NewCond =
@@ -2649,7 +2720,7 @@ static bool SimplifyIndirectBrOnSelect(IndirectBrInst *IBI, SelectInst *SI) {
 /// the PHI, merging the third icmp into the switch.
 static bool TryToSimplifyUncondBranchWithICmpInIt(
     ICmpInst *ICI, IRBuilder<> &Builder, const TargetTransformInfo &TTI,
-    const DataLayout *DL) {
+    unsigned BonusInstThreshold, const DataLayout *DL, AssumptionCache *AC) {
   BasicBlock *BB = ICI->getParent();
 
   // If the block has any PHIs in it or the icmp has multiple uses, it is too
@@ -2682,7 +2753,7 @@ static bool TryToSimplifyUncondBranchWithICmpInIt(
       ICI->eraseFromParent();
     }
     // BB is now empty, so it is likely to simplify away.
-    return SimplifyCFG(BB, TTI, DL) | true;
+    return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true;
   }
 
   // Ok, the block is reachable from the default dest.  If the constant we're
@@ -2698,7 +2769,7 @@ static bool TryToSimplifyUncondBranchWithICmpInIt(
     ICI->replaceAllUsesWith(V);
     ICI->eraseFromParent();
     // BB is now empty, so it is likely to simplify away.
-    return SimplifyCFG(BB, TTI, DL) | true;
+    return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true;
   }
 
   // The use of the icmp has to be in the 'end' block, by the only PHI node in
@@ -2759,24 +2830,17 @@ static bool SimplifyBranchOnICmpChain(BranchInst *BI, const DataLayout *DL,
   Instruction *Cond = dyn_cast<Instruction>(BI->getCondition());
   if (!Cond) return false;
 
-
   // Change br (X == 0 | X == 1), T, F into a switch instruction.
   // If this is a bunch of seteq's or'd together, or if it's a bunch of
   // 'setne's and'ed together, collect them.
-  Value *CompVal = nullptr;
-  std::vector<ConstantInt*> Values;
-  bool TrueWhenEqual = true;
-  Value *ExtraCase = nullptr;
-  unsigned UsedICmps = 0;
-
-  if (Cond->getOpcode() == Instruction::Or) {
-    CompVal = GatherConstantCompares(Cond, Values, ExtraCase, DL, true,
-                                     UsedICmps);
-  } else if (Cond->getOpcode() == Instruction::And) {
-    CompVal = GatherConstantCompares(Cond, Values, ExtraCase, DL, false,
-                                     UsedICmps);
-    TrueWhenEqual = false;
-  }
+
+  // Try to gather values from a chain of and/or to be turned into a switch
+  ConstantComparesGatherer ConstantCompare(Cond, DL);
+  // Unpack the result
+  SmallVectorImpl<ConstantInt*> &Values = ConstantCompare.Vals;
+  Value *CompVal = ConstantCompare.CompValue;
+  unsigned UsedICmps = ConstantCompare.UsedICmps;
+  Value *ExtraCase = ConstantCompare.Extra;
 
   // If we didn't have a multiply compared value, fail.
   if (!CompVal) return false;
@@ -2785,6 +2849,8 @@ static bool SimplifyBranchOnICmpChain(BranchInst *BI, const DataLayout *DL,
   if (UsedICmps <= 1)
     return false;
 
+  bool TrueWhenEqual = (Cond->getOpcode() == Instruction::Or);
+
   // There might be duplicate constants in the list, which the switch
   // instruction can't handle, remove them now.
   array_pod_sort(Values.begin(), Values.end(), ConstantIntSortPredicate);
@@ -2954,7 +3020,7 @@ bool SimplifyCFGOpt::SimplifyReturn(ReturnInst *RI, IRBuilder<> &Builder) {
     }
 
     // If we eliminated all predecessors of the block, delete the block now.
-    if (pred_begin(BB) == pred_end(BB))
+    if (pred_empty(BB))
       // We know there are no successors, so just nuke the block.
       BB->eraseFromParent();
 
@@ -3127,7 +3193,7 @@ bool SimplifyCFGOpt::SimplifyUnreachable(UnreachableInst *UI) {
   }
 
   // If this block is now dead, remove it.
-  if (pred_begin(BB) == pred_end(BB) &&
+  if (pred_empty(BB) &&
       BB != &BB->getParent()->getEntryBlock()) {
     // We know there are no successors, so just nuke the block.
     BB->eraseFromParent();
@@ -3208,11 +3274,12 @@ static bool TurnSwitchRangeIntoICmp(SwitchInst *SI, IRBuilder<> &Builder) {
 
 /// EliminateDeadSwitchCases - Compute masked bits for the condition of a switch
 /// and use it to remove dead cases.
-static bool EliminateDeadSwitchCases(SwitchInst *SI) {
+static bool EliminateDeadSwitchCases(SwitchInst *SI, const DataLayout *DL,
+                                     AssumptionCache *AC) {
   Value *Cond = SI->getCondition();
   unsigned Bits = Cond->getType()->getIntegerBitWidth();
   APInt KnownZero(Bits, 0), KnownOne(Bits, 0);
-  computeKnownBits(Cond, KnownZero, KnownOne);
+  computeKnownBits(Cond, KnownZero, KnownOne, DL, 0, AC, SI);
 
   // Gather dead cases.
   SmallVector<ConstantInt*, 8> DeadCases;
@@ -3419,6 +3486,21 @@ GetCaseResults(SwitchInst *SI,
       continue;
     } else if (Constant *C = ConstantFold(I, ConstantPool, DL)) {
       // Instruction is side-effect free and constant.
+
+      // If the instruction has uses outside this block or a phi node slot for
+      // the block, it is not safe to bypass the instruction since it would then
+      // no longer dominate all its uses.
+      for (auto &Use : I->uses()) {
+        User *User = Use.getUser();
+        if (Instruction *I = dyn_cast<Instruction>(User))
+          if (I->getParent() == CaseDest)
+            continue;
+        if (PHINode *Phi = dyn_cast<PHINode>(User))
+          if (Phi->getIncomingBlock(Use) == CaseDest)
+            continue;
+        return false;
+      }
+
       ConstantPool.insert(std::make_pair(I, C));
     } else {
       break;
@@ -3444,12 +3526,6 @@ GetCaseResults(SwitchInst *SI,
     if (!ConstVal)
       return false;
 
-    // Note: If the constant comes from constant-propagating the case value
-    // through the CaseDest basic block, it will be safe to remove the
-    // instructions in that block. They cannot be used (except in the phi nodes
-    // we visit) outside CaseDest, because that block does not dominate its
-    // successor. If it did, we would not be in this phi node.
-
     // Be conservative about which kinds of constants we support.
     if (!ValidLookupTableConstant(ConstVal))
       return false;
@@ -3460,6 +3536,163 @@ GetCaseResults(SwitchInst *SI,
   return Res.size() > 0;
 }
 
+// MapCaseToResult - Helper function used to
+// add CaseVal to the list of cases that generate Result.
+static void MapCaseToResult(ConstantInt *CaseVal,
+    SwitchCaseResultVectorTy &UniqueResults,
+    Constant *Result) {
+  for (auto &I : UniqueResults) {
+    if (I.first == Result) {
+      I.second.push_back(CaseVal);
+      return;
+    }
+  }
+  UniqueResults.push_back(std::make_pair(Result,
+        SmallVector<ConstantInt*, 4>(1, CaseVal)));
+}
+
+// InitializeUniqueCases - Helper function that initializes a map containing
+// results for the PHI node of the common destination block for a switch
+// instruction. Returns false if multiple PHI nodes have been found or if
+// there is not a common destination block for the switch.
+static bool InitializeUniqueCases(
+    SwitchInst *SI, const DataLayout *DL, PHINode *&PHI,
+    BasicBlock *&CommonDest,
+    SwitchCaseResultVectorTy &UniqueResults,
+    Constant *&DefaultResult) {
+  for (auto &I : SI->cases()) {
+    ConstantInt *CaseVal = I.getCaseValue();
+
+    // Resulting value at phi nodes for this case value.
+    SwitchCaseResultsTy Results;
+    if (!GetCaseResults(SI, CaseVal, I.getCaseSuccessor(), &CommonDest, Results,
+                        DL))
+      return false;
+
+    // Only one value per case is permitted
+    if (Results.size() > 1)
+      return false;
+    MapCaseToResult(CaseVal, UniqueResults, Results.begin()->second);
+
+    // Check the PHI consistency.
+    if (!PHI)
+      PHI = Results[0].first;
+    else if (PHI != Results[0].first)
+      return false;
+  }
+  // Find the default result value.
+  SmallVector<std::pair<PHINode *, Constant *>, 1> DefaultResults;
+  BasicBlock *DefaultDest = SI->getDefaultDest();
+  GetCaseResults(SI, nullptr, SI->getDefaultDest(), &CommonDest, DefaultResults,
+                 DL);
+  // If the default value is not found abort unless the default destination
+  // is unreachable.
+  DefaultResult =
+      DefaultResults.size() == 1 ? DefaultResults.begin()->second : nullptr;
+  if ((!DefaultResult &&
+        !isa<UnreachableInst>(DefaultDest->getFirstNonPHIOrDbg())))
+    return false;
+
+  return true;
+}
+
+// ConvertTwoCaseSwitch - Helper function that checks if it is possible to
+// transform a switch with only two cases (or two cases + default)
+// that produces a result into a value select.
+// Example:
+// switch (a) {
+//   case 10:                %0 = icmp eq i32 %a, 10
+//     return 10;            %1 = select i1 %0, i32 10, i32 4
+//   case 20:        ---->   %2 = icmp eq i32 %a, 20
+//     return 2;             %3 = select i1 %2, i32 2, i32 %1
+//   default:
+//     return 4;
+// }
+static Value *
+ConvertTwoCaseSwitch(const SwitchCaseResultVectorTy &ResultVector,
+                     Constant *DefaultResult, Value *Condition,
+                     IRBuilder<> &Builder) {
+  assert(ResultVector.size() == 2 &&
+      "We should have exactly two unique results at this point");
+  // If we are selecting between only two cases transform into a simple
+  // select or a two-way select if default is possible.
+  if (ResultVector[0].second.size() == 1 &&
+      ResultVector[1].second.size() == 1) {
+    ConstantInt *const FirstCase = ResultVector[0].second[0];
+    ConstantInt *const SecondCase = ResultVector[1].second[0];
+
+    bool DefaultCanTrigger = DefaultResult;
+    Value *SelectValue = ResultVector[1].first;
+    if (DefaultCanTrigger) {
+      Value *const ValueCompare =
+          Builder.CreateICmpEQ(Condition, SecondCase, "switch.selectcmp");
+      SelectValue = Builder.CreateSelect(ValueCompare, ResultVector[1].first,
+                                         DefaultResult, "switch.select");
+    }
+    Value *const ValueCompare =
+        Builder.CreateICmpEQ(Condition, FirstCase, "switch.selectcmp");
+    return Builder.CreateSelect(ValueCompare, ResultVector[0].first, SelectValue,
+                                "switch.select");
+  }
+
+  return nullptr;
+}
+
+// RemoveSwitchAfterSelectConversion - Helper function to cleanup a switch
+// instruction that has been converted into a select, fixing up PHI nodes and
+// basic blocks.
+static void RemoveSwitchAfterSelectConversion(SwitchInst *SI, PHINode *PHI,
+                                              Value *SelectValue,
+                                              IRBuilder<> &Builder) {
+  BasicBlock *SelectBB = SI->getParent();
+  while (PHI->getBasicBlockIndex(SelectBB) >= 0)
+    PHI->removeIncomingValue(SelectBB);
+  PHI->addIncoming(SelectValue, SelectBB);
+
+  Builder.CreateBr(PHI->getParent());
+
+  // Remove the switch.
+  for (unsigned i = 0, e = SI->getNumSuccessors(); i < e; ++i) {
+    BasicBlock *Succ = SI->getSuccessor(i);
+
+    if (Succ == PHI->getParent())
+      continue;
+    Succ->removePredecessor(SelectBB);
+  }
+  SI->eraseFromParent();
+}
+
+/// SwitchToSelect - If the switch is only used to initialize one or more
+/// phi nodes in a common successor block with only two different
+/// constant values, replace the switch with select.
+static bool SwitchToSelect(SwitchInst *SI, IRBuilder<> &Builder,
+                           const DataLayout *DL, AssumptionCache *AC) {
+  Value *const Cond = SI->getCondition();
+  PHINode *PHI = nullptr;
+  BasicBlock *CommonDest = nullptr;
+  Constant *DefaultResult;
+  SwitchCaseResultVectorTy UniqueResults;
+  // Collect all the cases that will deliver the same value from the switch.
+  if (!InitializeUniqueCases(SI, DL, PHI, CommonDest, UniqueResults,
+                             DefaultResult))
+    return false;
+  // Selects choose between maximum two values.
+  if (UniqueResults.size() != 2)
+    return false;
+  assert(PHI != nullptr && "PHI for value select not found");
+
+  Builder.SetInsertPoint(SI);
+  Value *SelectValue = ConvertTwoCaseSwitch(
+      UniqueResults,
+      DefaultResult, Cond, Builder);
+  if (SelectValue) {
+    RemoveSwitchAfterSelectConversion(SI, PHI, SelectValue, Builder);
+    return true;
+  }
+  // The switch couldn't be converted into a select.
+  return false;
+}
+
 namespace {
   /// SwitchLookupTable - This class represents a lookup table that can be used
   /// to replace a switch.
@@ -3493,6 +3726,11 @@ namespace {
       // store that single value and return it for each lookup.
       SingleValueKind,
 
+      // For tables where there is a linear relationship between table index
+      // and values. We calculate the result with a simple multiplication
+      // and addition instead of a table lookup.
+      LinearMapKind,
+
       // For small tables with integer elements, we can pack them into a bitmap
       // that fits into a target-legal register. Values are retrieved by
       // shift and mask operations.
@@ -3510,6 +3748,10 @@ namespace {
     ConstantInt *BitMap;
     IntegerType *BitMapElementTy;
 
+    // For LinearMapKind, these are the constants used to derive the value.
+    ConstantInt *LinearOffset;
+    ConstantInt *LinearMultiplier;
+
     // For ArrayKind, this is the array.
     GlobalVariable *Array;
   };
@@ -3522,7 +3764,7 @@ SwitchLookupTable::SwitchLookupTable(Module &M,
                                      Constant *DefaultValue,
                                      const DataLayout *DL)
     : SingleValue(nullptr), BitMap(nullptr), BitMapElementTy(nullptr),
-      Array(nullptr) {
+      LinearOffset(nullptr), LinearMultiplier(nullptr), Array(nullptr) {
   assert(Values.size() && "Can't build lookup table without values!");
   assert(TableSize >= Values.size() && "Can't fit values in table!");
 
@@ -3567,6 +3809,43 @@ SwitchLookupTable::SwitchLookupTable(Module &M,
     return;
   }
 
+  // Check if we can derive the value with a linear transformation from the
+  // table index.
+  if (isa<IntegerType>(ValueType)) {
+    bool LinearMappingPossible = true;
+    APInt PrevVal;
+    APInt DistToPrev;
+    assert(TableSize >= 2 && "Should be a SingleValue table.");
+    // Check if there is the same distance between two consecutive values.
+    for (uint64_t I = 0; I < TableSize; ++I) {
+      ConstantInt *ConstVal = dyn_cast<ConstantInt>(TableContents[I]);
+      if (!ConstVal) {
+        // This is an undef. We could deal with it, but undefs in lookup tables
+        // are very seldom. It's probably not worth the additional complexity.
+        LinearMappingPossible = false;
+        break;
+      }
+      APInt Val = ConstVal->getValue();
+      if (I != 0) {
+        APInt Dist = Val - PrevVal;
+        if (I == 1) {
+          DistToPrev = Dist;
+        } else if (Dist != DistToPrev) {
+          LinearMappingPossible = false;
+          break;
+        }
+      }
+      PrevVal = Val;
+    }
+    if (LinearMappingPossible) {
+      LinearOffset = cast<ConstantInt>(TableContents[0]);
+      LinearMultiplier = ConstantInt::get(M.getContext(), DistToPrev);
+      Kind = LinearMapKind;
+      ++NumLinearMaps;
+      return;
+    }
+  }
+
   // If the type is integer and the table fits in a register, build a bitmap.
   if (WouldFitInRegister(DL, TableSize, ValueType)) {
     IntegerType *IT = cast<IntegerType>(ValueType);
@@ -3602,6 +3881,16 @@ Value *SwitchLookupTable::BuildLookup(Value *Index, IRBuilder<> &Builder) {
   switch (Kind) {
     case SingleValueKind:
       return SingleValue;
+    case LinearMapKind: {
+      // Derive the result value from the input value.
+      Value *Result = Builder.CreateIntCast(Index, LinearMultiplier->getType(),
+                                            false, "switch.idx.cast");
+      if (!LinearMultiplier->isOne())
+        Result = Builder.CreateMul(Result, LinearMultiplier, "switch.idx.mult");
+      if (!LinearOffset->isZero())
+        Result = Builder.CreateAdd(Result, LinearOffset, "switch.offset");
+      return Result;
+    }
     case BitMapKind: {
       // Type of the bitmap (e.g. i59).
       IntegerType *MapTy = BitMap->getType();
@@ -3673,9 +3962,8 @@ static bool ShouldBuildLookupTable(SwitchInst *SI,
 
   bool AllTablesFitInRegister = true;
   bool HasIllegalType = false;
-  for (SmallDenseMap<PHINode*, Type*>::const_iterator I = ResultTypes.begin(),
-       E = ResultTypes.end(); I != E; ++I) {
-    Type *Ty = I->second;
+  for (const auto &I : ResultTypes) {
+    Type *Ty = I.second;
 
     // Saturate this flag to true.
     HasIllegalType = HasIllegalType || !TTI.isTypeLegal(Ty);
@@ -3705,6 +3993,89 @@ static bool ShouldBuildLookupTable(SwitchInst *SI,
   return SI->getNumCases() * 10 >= TableSize * 4;
 }
 
+/// Try to reuse the switch table index compare. Following pattern:
+/// \code
+///     if (idx < tablesize)
+///        r = table[idx]; // table does not contain default_value
+///     else
+///        r = default_value;
+///     if (r != default_value)
+///        ...
+/// \endcode
+/// Is optimized to:
+/// \code
+///     cond = idx < tablesize;
+///     if (cond)
+///        r = table[idx];
+///     else
+///        r = default_value;
+///     if (cond)
+///        ...
+/// \endcode
+/// Jump threading will then eliminate the second if(cond).
+static void reuseTableCompare(User *PhiUser, BasicBlock *PhiBlock,
+          BranchInst *RangeCheckBranch, Constant *DefaultValue,
+          const SmallVectorImpl<std::pair<ConstantInt*, Constant*> >& Values) {
+
+  ICmpInst *CmpInst = dyn_cast<ICmpInst>(PhiUser);
+  if (!CmpInst)
+    return;
+
+  // We require that the compare is in the same block as the phi so that jump
+  // threading can do its work afterwards.
+  if (CmpInst->getParent() != PhiBlock)
+    return;
+
+  Constant *CmpOp1 = dyn_cast<Constant>(CmpInst->getOperand(1));
+  if (!CmpOp1)
+    return;
+
+  Value *RangeCmp = RangeCheckBranch->getCondition();
+  Constant *TrueConst = ConstantInt::getTrue(RangeCmp->getType());
+  Constant *FalseConst = ConstantInt::getFalse(RangeCmp->getType());
+
+  // Check if the compare with the default value is constant true or false.
+  Constant *DefaultConst = ConstantExpr::getICmp(CmpInst->getPredicate(),
+                                                 DefaultValue, CmpOp1, true);
+  if (DefaultConst != TrueConst && DefaultConst != FalseConst)
+    return;
+
+  // Check if the compare with the case values is distinct from the default
+  // compare result.
+  for (auto ValuePair : Values) {
+    Constant *CaseConst = ConstantExpr::getICmp(CmpInst->getPredicate(),
+                              ValuePair.second, CmpOp1, true);
+    if (!CaseConst || CaseConst == DefaultConst)
+      return;
+    assert((CaseConst == TrueConst || CaseConst == FalseConst) &&
+           "Expect true or false as compare result.");
+  }
+ 
+  // Check if the branch instruction dominates the phi node. It's a simple
+  // dominance check, but sufficient for our needs.
+  // Although this check is invariant in the calling loops, it's better to do it
+  // at this late stage. Practically we do it at most once for a switch.
+  BasicBlock *BranchBlock = RangeCheckBranch->getParent();
+  for (auto PI = pred_begin(PhiBlock), E = pred_end(PhiBlock); PI != E; ++PI) {
+    BasicBlock *Pred = *PI;
+    if (Pred != BranchBlock && Pred->getUniquePredecessor() != BranchBlock)
+      return;
+  }
+
+  if (DefaultConst == FalseConst) {
+    // The compare yields the same result. We can replace it.
+    CmpInst->replaceAllUsesWith(RangeCmp);
+    ++NumTableCmpReuses;
+  } else {
+    // The compare yields the same result, just inverted. We can replace it.
+    Value *InvertedTableCmp = BinaryOperator::CreateXor(RangeCmp,
+                ConstantInt::get(RangeCmp->getType(), 1), "inverted.cmp",
+                RangeCheckBranch);
+    CmpInst->replaceAllUsesWith(InvertedTableCmp);
+    ++NumTableCmpReuses;
+  }
+}
+
 /// SwitchToLookupTable - If the switch is only used to initialize one or more
 /// phi nodes in a common successor block with different constant values,
 /// replace the switch with lookup tables.
@@ -3759,16 +4130,17 @@ static bool SwitchToLookupTable(SwitchInst *SI,
       return false;
 
     // Append the result from this case to the list for each phi.
-    for (ResultsTy::iterator I = Results.begin(), E = Results.end(); I!=E; ++I) {
-      if (!ResultLists.count(I->first))
-        PHIs.push_back(I->first);
-      ResultLists[I->first].push_back(std::make_pair(CaseVal, I->second));
+    for (const auto &I : Results) {
+      PHINode *PHI = I.first;
+      Constant *Value = I.second;
+      if (!ResultLists.count(PHI))
+        PHIs.push_back(PHI);
+      ResultLists[PHI].push_back(std::make_pair(CaseVal, Value));
     }
   }
 
   // Keep track of the result types.
-  for (size_t I = 0, E = PHIs.size(); I != E; ++I) {
-    PHINode *PHI = PHIs[I];
+  for (PHINode *PHI : PHIs) {
     ResultTypes[PHI] = ResultLists[PHI][0].second->getType();
   }
 
@@ -3780,11 +4152,9 @@ static bool SwitchToLookupTable(SwitchInst *SI,
   // If the table has holes, we need a constant result for the default case
   // or a bitmask that fits in a register.
   SmallVector<std::pair<PHINode*, Constant*>, 4> DefaultResultsList;
-  bool HasDefaultResults = false;
-  if (TableHasHoles) {
-    HasDefaultResults = GetCaseResults(SI, nullptr, SI->getDefaultDest(),
+  bool HasDefaultResults = GetCaseResults(SI, nullptr, SI->getDefaultDest(),
                                        &CommonDest, DefaultResultsList, DL);
-  }
+
   bool NeedMask = (TableHasHoles && !HasDefaultResults);
   if (NeedMask) {
     // As an extra penalty for the validity test we require more cases.
@@ -3794,9 +4164,9 @@ static bool SwitchToLookupTable(SwitchInst *SI,
       return false;
   }
 
-  for (size_t I = 0, E = DefaultResultsList.size(); I != E; ++I) {
-    PHINode *PHI = DefaultResultsList[I].first;
-    Constant *Result = DefaultResultsList[I].second;
+  for (const auto &I : DefaultResultsList) {
+    PHINode *PHI = I.first;
+    Constant *Result = I.second;
     DefaultResults[PHI] = Result;
   }
 
@@ -3827,14 +4197,19 @@ static bool SwitchToLookupTable(SwitchInst *SI,
   // lookup table BB. Otherwise, check if the condition value is within the case
   // range. If it is so, branch to the new BB. Otherwise branch to SI's default
   // destination.
+  BranchInst *RangeCheckBranch = nullptr;
+
   const bool GeneratingCoveredLookupTable = MaxTableSize == TableSize;
   if (GeneratingCoveredLookupTable) {
     Builder.CreateBr(LookupBB);
-    SI->getDefaultDest()->removePredecessor(SI->getParent());
+    // We cached PHINodes in PHIs, to avoid accessing deleted PHINodes later,
+    // do not delete PHINodes here.
+    SI->getDefaultDest()->removePredecessor(SI->getParent(),
+                                            true/*DontDeleteUselessPHIs*/);
   } else {
     Value *Cmp = Builder.CreateICmpULT(TableIndex, ConstantInt::get(
                                        MinCaseVal->getType(), TableSize));
-    Builder.CreateCondBr(Cmp, LookupBB, SI->getDefaultDest());
+    RangeCheckBranch = Builder.CreateCondBr(Cmp, LookupBB, SI->getDefaultDest());
   }
 
   // Populate the BB that does the lookups.
@@ -3851,9 +4226,12 @@ static bool SwitchToLookupTable(SwitchInst *SI,
                                   CommonDest->getParent(),
                                   CommonDest);
 
+    // Make the mask's bitwidth at least 8bit and a power-of-2 to avoid
+    // unnecessary illegal types.
+    uint64_t TableSizePowOf2 = NextPowerOf2(std::max(7ULL, TableSize - 1ULL));
+    APInt MaskInt(TableSizePowOf2, 0);
+    APInt One(TableSizePowOf2, 1);
     // Build bitmask; fill in a 1 bit for every case.
-    APInt MaskInt(TableSize, 0);
-    APInt One(TableSize, 1);
     const ResultListTy &ResultList = ResultLists[PHIs[0]];
     for (size_t I = 0, E = ResultList.size(); I != E; ++I) {
       uint64_t Idx = (ResultList[I].first->getValue() -
@@ -3882,11 +4260,11 @@ static bool SwitchToLookupTable(SwitchInst *SI,
   bool ReturnedEarly = false;
   for (size_t I = 0, E = PHIs.size(); I != E; ++I) {
     PHINode *PHI = PHIs[I];
+    const ResultListTy &ResultList = ResultLists[PHI];
 
     // If using a bitmask, use any value to fill the lookup table holes.
     Constant *DV = NeedMask ? ResultLists[PHI][0].second : DefaultResults[PHI];
-    SwitchLookupTable Table(Mod, TableSize, MinCaseVal, ResultLists[PHI],
-                            DV, DL);
+    SwitchLookupTable Table(Mod, TableSize, MinCaseVal, ResultList, DV, DL);
 
     Value *Result = Table.BuildLookup(TableIndex, Builder);
 
@@ -3899,6 +4277,16 @@ static bool SwitchToLookupTable(SwitchInst *SI,
       break;
     }
 
+    // Do a small peephole optimization: re-use the switch table compare if
+    // possible.
+    if (!TableHasHoles && HasDefaultResults && RangeCheckBranch) {
+      BasicBlock *PhiBlock = PHI->getParent();
+      // Search for compare instructions which use the phi.
+      for (auto *User : PHI->users()) {
+        reuseTableCompare(User, PhiBlock, RangeCheckBranch, DV, ResultList);
+      }
+    }
+
     PHI->addIncoming(Result, LookupBB);
   }
 
@@ -3929,12 +4317,12 @@ bool SimplifyCFGOpt::SimplifySwitch(SwitchInst *SI, IRBuilder<> &Builder) {
     // see if that predecessor totally determines the outcome of this switch.
     if (BasicBlock *OnlyPred = BB->getSinglePredecessor())
       if (SimplifyEqualityComparisonWithOnlyPredecessor(SI, OnlyPred, Builder))
-        return SimplifyCFG(BB, TTI, DL) | true;
+        return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true;
 
     Value *Cond = SI->getCondition();
     if (SelectInst *Select = dyn_cast<SelectInst>(Cond))
       if (SimplifySwitchOnSelect(SI, Select))
-        return SimplifyCFG(BB, TTI, DL) | true;
+        return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true;
 
     // If the block only contains the switch, see if we can fold the block
     // away into any preds.
@@ -3944,22 +4332,25 @@ bool SimplifyCFGOpt::SimplifySwitch(SwitchInst *SI, IRBuilder<> &Builder) {
       ++BBI;
     if (SI == &*BBI)
       if (FoldValueComparisonIntoPredecessors(SI, Builder))
-        return SimplifyCFG(BB, TTI, DL) | true;
+        return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true;
   }
 
   // Try to transform the switch into an icmp and a branch.
   if (TurnSwitchRangeIntoICmp(SI, Builder))
-    return SimplifyCFG(BB, TTI, DL) | true;
+    return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true;
 
   // Remove unreachable cases.
-  if (EliminateDeadSwitchCases(SI))
-    return SimplifyCFG(BB, TTI, DL) | true;
+  if (EliminateDeadSwitchCases(SI, DL, AC))
+    return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true;
+
+  if (SwitchToSelect(SI, Builder, DL, AC))
+    return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true;
 
   if (ForwardSwitchConditionToPHI(SI))
-    return SimplifyCFG(BB, TTI, DL) | true;
+    return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true;
 
   if (SwitchToLookupTable(SI, Builder, TTI, DL))
-    return SimplifyCFG(BB, TTI, DL) | true;
+    return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true;
 
   return false;
 }
@@ -3972,7 +4363,7 @@ bool SimplifyCFGOpt::SimplifyIndirectBr(IndirectBrInst *IBI) {
   SmallPtrSet<Value *, 8> Succs;
   for (unsigned i = 0, e = IBI->getNumDestinations(); i != e; ++i) {
     BasicBlock *Dest = IBI->getDestination(i);
-    if (!Dest->hasAddressTaken() || !Succs.insert(Dest)) {
+    if (!Dest->hasAddressTaken() || !Succs.insert(Dest).second) {
       Dest->removePredecessor(BB);
       IBI->removeDestination(i);
       --i; --e;
@@ -3996,7 +4387,7 @@ bool SimplifyCFGOpt::SimplifyIndirectBr(IndirectBrInst *IBI) {
 
   if (SelectInst *SI = dyn_cast<SelectInst>(IBI->getAddress())) {
     if (SimplifyIndirectBrOnSelect(IBI, SI))
-      return SimplifyCFG(BB, TTI, DL) | true;
+      return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true;
   }
   return Changed;
 }
@@ -4008,7 +4399,7 @@ bool SimplifyCFGOpt::SimplifyUncondBranch(BranchInst *BI, IRBuilder<> &Builder){
     return true;
 
   // If the Terminator is the only non-phi instruction, simplify the block.
-  BasicBlock::iterator I = BB->getFirstNonPHIOrDbgOrLifetime();
+  BasicBlock::iterator I = BB->getFirstNonPHIOrDbg();
   if (I->isTerminator() && BB != &BB->getParent()->getEntryBlock() &&
       TryToSimplifyUncondBranchFromEmptyBlock(BB))
     return true;
@@ -4020,7 +4411,8 @@ bool SimplifyCFGOpt::SimplifyUncondBranch(BranchInst *BI, IRBuilder<> &Builder){
       for (++I; isa<DbgInfoIntrinsic>(I); ++I)
         ;
       if (I->isTerminator() &&
-          TryToSimplifyUncondBranchWithICmpInIt(ICI, Builder, TTI, DL))
+          TryToSimplifyUncondBranchWithICmpInIt(ICI, Builder, TTI,
+                                                BonusInstThreshold, DL, AC))
         return true;
     }
 
@@ -4028,8 +4420,8 @@ bool SimplifyCFGOpt::SimplifyUncondBranch(BranchInst *BI, IRBuilder<> &Builder){
   // branches to us and our successor, fold the comparison into the
   // predecessor and use logical operations to update the incoming value
   // for PHI nodes in common successor.
-  if (FoldBranchToCommonDest(BI, DL))
-    return SimplifyCFG(BB, TTI, DL) | true;
+  if (FoldBranchToCommonDest(BI, DL, BonusInstThreshold))
+    return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true;
   return false;
 }
 
@@ -4044,7 +4436,7 @@ bool SimplifyCFGOpt::SimplifyCondBranch(BranchInst *BI, IRBuilder<> &Builder) {
     // switch.
     if (BasicBlock *OnlyPred = BB->getSinglePredecessor())
       if (SimplifyEqualityComparisonWithOnlyPredecessor(BI, OnlyPred, Builder))
-        return SimplifyCFG(BB, TTI, DL) | true;
+        return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true;
 
     // This block must be empty, except for the setcond inst, if it exists.
     // Ignore dbg intrinsics.
@@ -4054,14 +4446,14 @@ bool SimplifyCFGOpt::SimplifyCondBranch(BranchInst *BI, IRBuilder<> &Builder) {
       ++I;
     if (&*I == BI) {
       if (FoldValueComparisonIntoPredecessors(BI, Builder))
-        return SimplifyCFG(BB, TTI, DL) | true;
+        return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true;
     } else if (&*I == cast<Instruction>(BI->getCondition())){
       ++I;
       // Ignore dbg intrinsics.
       while (isa<DbgInfoIntrinsic>(I))
         ++I;
       if (&*I == BI && FoldValueComparisonIntoPredecessors(BI, Builder))
-        return SimplifyCFG(BB, TTI, DL) | true;
+        return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true;
     }
   }
 
@@ -4072,8 +4464,8 @@ bool SimplifyCFGOpt::SimplifyCondBranch(BranchInst *BI, IRBuilder<> &Builder) {
   // If this basic block is ONLY a compare and a branch, and if a predecessor
   // branches to us and one of our successors, fold the comparison into the
   // predecessor and use logical operations to pick the right destination.
-  if (FoldBranchToCommonDest(BI, DL))
-    return SimplifyCFG(BB, TTI, DL) | true;
+  if (FoldBranchToCommonDest(BI, DL, BonusInstThreshold))
+    return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true;
 
   // We have a conditional branch to two blocks that are only reachable
   // from BI.  We know that the condbr dominates the two blocks, so see if
@@ -4082,7 +4474,7 @@ bool SimplifyCFGOpt::SimplifyCondBranch(BranchInst *BI, IRBuilder<> &Builder) {
   if (BI->getSuccessor(0)->getSinglePredecessor()) {
     if (BI->getSuccessor(1)->getSinglePredecessor()) {
       if (HoistThenElseCodeToIf(BI, DL))
-        return SimplifyCFG(BB, TTI, DL) | true;
+        return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true;
     } else {
       // If Successor #1 has multiple preds, we may be able to conditionally
       // execute Successor #0 if it branches to Successor #1.
@@ -4090,7 +4482,7 @@ bool SimplifyCFGOpt::SimplifyCondBranch(BranchInst *BI, IRBuilder<> &Builder) {
       if (Succ0TI->getNumSuccessors() == 1 &&
           Succ0TI->getSuccessor(0) == BI->getSuccessor(1))
         if (SpeculativelyExecuteBB(BI, BI->getSuccessor(0), DL))
-          return SimplifyCFG(BB, TTI, DL) | true;
+          return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true;
     }
   } else if (BI->getSuccessor(1)->getSinglePredecessor()) {
     // If Successor #0 has multiple preds, we may be able to conditionally
@@ -4099,7 +4491,7 @@ bool SimplifyCFGOpt::SimplifyCondBranch(BranchInst *BI, IRBuilder<> &Builder) {
     if (Succ1TI->getNumSuccessors() == 1 &&
         Succ1TI->getSuccessor(0) == BI->getSuccessor(0))
       if (SpeculativelyExecuteBB(BI, BI->getSuccessor(1), DL))
-        return SimplifyCFG(BB, TTI, DL) | true;
+        return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true;
   }
 
   // If this is a branch on a phi node in the current block, thread control
@@ -4107,14 +4499,14 @@ bool SimplifyCFGOpt::SimplifyCondBranch(BranchInst *BI, IRBuilder<> &Builder) {
   if (PHINode *PN = dyn_cast<PHINode>(BI->getCondition()))
     if (PN->getParent() == BI->getParent())
       if (FoldCondBranchOnPHI(BI, DL))
-        return SimplifyCFG(BB, TTI, DL) | true;
+        return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true;
 
   // Scan predecessor blocks for conditional branches.
   for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
     if (BranchInst *PBI = dyn_cast<BranchInst>((*PI)->getTerminator()))
       if (PBI != BI && PBI->isConditional())
         if (SimplifyCondBranchToCondBranch(PBI, BI))
-          return SimplifyCFG(BB, TTI, DL) | true;
+          return SimplifyCFG(BB, TTI, BonusInstThreshold, DL, AC) | true;
 
   return false;
 }
@@ -4195,7 +4587,7 @@ bool SimplifyCFGOpt::run(BasicBlock *BB) {
 
   // Remove basic blocks that have no predecessors (except the entry block)...
   // or that just have themself as a predecessor.  These are unreachable.
-  if ((pred_begin(BB) == pred_end(BB) &&
+  if ((pred_empty(BB) &&
        BB != &BB->getParent()->getEntryBlock()) ||
       BB->getSinglePredecessor() == BB) {
     DEBUG(dbgs() << "Removing BB: \n" << *BB);
@@ -4258,6 +4650,7 @@ bool SimplifyCFGOpt::run(BasicBlock *BB) {
 /// of the CFG.  It returns true if a modification was made.
 ///
 bool llvm::SimplifyCFG(BasicBlock *BB, const TargetTransformInfo &TTI,
-                       const DataLayout *DL) {
-  return SimplifyCFGOpt(TTI, DL).run(BB);
+                       unsigned BonusInstThreshold, const DataLayout *DL,
+                       AssumptionCache *AC) {
+  return SimplifyCFGOpt(TTI, BonusInstThreshold, DL, AC).run(BB);
 }
diff --git a/lib/Transforms/Utils/SimplifyIndVar.cpp b/lib/Transforms/Utils/SimplifyIndVar.cpp
index b284e6f6c1f6..f8aa1d3eec12 100644
--- a/lib/Transforms/Utils/SimplifyIndVar.cpp
+++ b/lib/Transforms/Utils/SimplifyIndVar.cpp
@@ -40,7 +40,7 @@ STATISTIC(NumElimRem     , "Number of IV remainder operations eliminated");
 STATISTIC(NumElimCmp     , "Number of IV comparisons eliminated");
 
 namespace {
-  /// SimplifyIndvar - This is a utility for simplifying induction variables
+  /// This is a utility for simplifying induction variables
   /// based on ScalarEvolution. It is the primary instrument of the
   /// IndvarSimplify pass, but it may also be directly invoked to cleanup after
   /// other loop passes that preserve SCEV.
@@ -80,13 +80,14 @@ namespace {
     void eliminateIVComparison(ICmpInst *ICmp, Value *IVOperand);
     void eliminateIVRemainder(BinaryOperator *Rem, Value *IVOperand,
                               bool IsSigned);
+    bool strengthenOverflowingOperation(BinaryOperator *OBO, Value *IVOperand);
 
     Instruction *splitOverflowIntrinsic(Instruction *IVUser,
                                         const DominatorTree *DT);
   };
 }
 
-/// foldIVUser - Fold an IV operand into its use.  This removes increments of an
+/// Fold an IV operand into its use.  This removes increments of an
 /// aligned IV when used by a instruction that ignores the low bits.
 ///
 /// IVOperand is guaranteed SCEVable, but UseInst may not be.
@@ -152,7 +153,7 @@ Value *SimplifyIndvar::foldIVUser(Instruction *UseInst, Instruction *IVOperand)
   return IVSrc;
 }
 
-/// eliminateIVComparison - SimplifyIVUsers helper for eliminating useless
+/// SimplifyIVUsers helper for eliminating useless
 /// comparisons against an induction variable.
 void SimplifyIndvar::eliminateIVComparison(ICmpInst *ICmp, Value *IVOperand) {
   unsigned IVOperIdx = 0;
@@ -188,7 +189,7 @@ void SimplifyIndvar::eliminateIVComparison(ICmpInst *ICmp, Value *IVOperand) {
   DeadInsts.push_back(ICmp);
 }
 
-/// eliminateIVRemainder - SimplifyIVUsers helper for eliminating useless
+/// SimplifyIVUsers helper for eliminating useless
 /// remainder operations operating on an induction variable.
 void SimplifyIndvar::eliminateIVRemainder(BinaryOperator *Rem,
                                       Value *IVOperand,
@@ -239,7 +240,7 @@ void SimplifyIndvar::eliminateIVRemainder(BinaryOperator *Rem,
   DeadInsts.push_back(Rem);
 }
 
-/// eliminateIVUser - Eliminate an operation that consumes a simple IV and has
+/// Eliminate an operation that consumes a simple IV and has
 /// no observable side-effect given the range of IV values.
 /// IVOperand is guaranteed SCEVable, but UseInst may not be.
 bool SimplifyIndvar::eliminateIVUser(Instruction *UseInst,
@@ -271,6 +272,120 @@ bool SimplifyIndvar::eliminateIVUser(Instruction *UseInst,
   return true;
 }
 
+/// Annotate BO with nsw / nuw if it provably does not signed-overflow /
+/// unsigned-overflow.  Returns true if anything changed, false otherwise.
+bool SimplifyIndvar::strengthenOverflowingOperation(BinaryOperator *BO,
+                                                    Value *IVOperand) {
+
+  // Currently we only handle instructions of the form "add <indvar> <value>"
+  // and "sub <indvar> <value>".
+  unsigned Op = BO->getOpcode();
+  if (!(Op == Instruction::Add || Op == Instruction::Sub))
+    return false;
+
+  // If BO is already both nuw and nsw then there is nothing left to do
+  if (BO->hasNoUnsignedWrap() && BO->hasNoSignedWrap())
+    return false;
+
+  IntegerType *IT = cast<IntegerType>(IVOperand->getType());
+  Value *OtherOperand = nullptr;
+  int OtherOperandIdx = -1;
+  if (BO->getOperand(0) == IVOperand) {
+    OtherOperand = BO->getOperand(1);
+    OtherOperandIdx = 1;
+  } else {
+    assert(BO->getOperand(1) == IVOperand && "only other use!");
+    OtherOperand = BO->getOperand(0);
+    OtherOperandIdx = 0;
+  }
+
+  bool Changed = false;
+  const SCEV *OtherOpSCEV = SE->getSCEV(OtherOperand);
+  if (OtherOpSCEV == SE->getCouldNotCompute())
+    return false;
+
+  if (Op == Instruction::Sub) {
+    // If the subtraction is of the form "sub <indvar>, <op>", then pretend it
+    // is "add <indvar>, -<op>" and continue, else bail out.
+    if (OtherOperandIdx != 1)
+      return false;
+
+    OtherOpSCEV = SE->getNegativeSCEV(OtherOpSCEV);
+  }
+
+  const SCEV *IVOpSCEV = SE->getSCEV(IVOperand);
+  const SCEV *ZeroSCEV = SE->getConstant(IVOpSCEV->getType(), 0);
+
+  if (!BO->hasNoSignedWrap()) {
+    // Upgrade the add to an "add nsw" if we can prove that it will never
+    // sign-overflow or sign-underflow.
+
+    const SCEV *SignedMax =
+      SE->getConstant(APInt::getSignedMaxValue(IT->getBitWidth()));
+    const SCEV *SignedMin =
+      SE->getConstant(APInt::getSignedMinValue(IT->getBitWidth()));
+
+    // The addition "IVOperand + OtherOp" does not sign-overflow if the result
+    // is sign-representable in 2's complement in the given bit-width.
+    //
+    // If OtherOp is SLT 0, then for an IVOperand in [SignedMin - OtherOp,
+    // SignedMax], "IVOperand + OtherOp" is in [SignedMin, SignedMax + OtherOp].
+    // Everything in [SignedMin, SignedMax + OtherOp] is representable since
+    // SignedMax + OtherOp is at least -1.
+    //
+    // If OtherOp is SGE 0, then for an IVOperand in [SignedMin, SignedMax -
+    // OtherOp], "IVOperand + OtherOp" is in [SignedMin + OtherOp, SignedMax].
+    // Everything in [SignedMin + OtherOp, SignedMax] is representable since
+    // SignedMin + OtherOp is at most -1.
+    //
+    // It follows that for all values of IVOperand in [SignedMin - smin(0,
+    // OtherOp), SignedMax - smax(0, OtherOp)] the result of the add is
+    // representable (i.e. there is no sign-overflow).
+
+    const SCEV *UpperDelta = SE->getSMaxExpr(ZeroSCEV, OtherOpSCEV);
+    const SCEV *UpperLimit = SE->getMinusSCEV(SignedMax, UpperDelta);
+
+    bool NeverSignedOverflows =
+      SE->isKnownPredicate(ICmpInst::ICMP_SLE, IVOpSCEV, UpperLimit);
+
+    if (NeverSignedOverflows) {
+      const SCEV *LowerDelta = SE->getSMinExpr(ZeroSCEV, OtherOpSCEV);
+      const SCEV *LowerLimit = SE->getMinusSCEV(SignedMin, LowerDelta);
+
+      bool NeverSignedUnderflows =
+        SE->isKnownPredicate(ICmpInst::ICMP_SGE, IVOpSCEV, LowerLimit);
+      if (NeverSignedUnderflows) {
+        BO->setHasNoSignedWrap(true);
+        Changed = true;
+      }
+    }
+  }
+
+  if (!BO->hasNoUnsignedWrap()) {
+    // Upgrade the add computing "IVOperand + OtherOp" to an "add nuw" if we can
+    // prove that it will never unsigned-overflow (i.e. the result will always
+    // be representable in the given bit-width).
+    //
+    // "IVOperand + OtherOp" is unsigned-representable in 2's complement iff it
+    // does not produce a carry.  "IVOperand + OtherOp" produces no carry iff
+    // IVOperand ULE (UnsignedMax - OtherOp).
+
+    const SCEV *UnsignedMax =
+      SE->getConstant(APInt::getMaxValue(IT->getBitWidth()));
+    const SCEV *UpperLimit = SE->getMinusSCEV(UnsignedMax, OtherOpSCEV);
+
+    bool NeverUnsignedOverflows =
+        SE->isKnownPredicate(ICmpInst::ICMP_ULE, IVOpSCEV, UpperLimit);
+
+    if (NeverUnsignedOverflows) {
+      BO->setHasNoUnsignedWrap(true);
+      Changed = true;
+    }
+  }
+
+  return Changed;
+}
+
 /// \brief Split sadd.with.overflow into add + sadd.with.overflow to allow
 /// analysis and optimization.
 ///
@@ -334,8 +449,7 @@ Instruction *SimplifyIndvar::splitOverflowIntrinsic(Instruction *IVUser,
   return AddInst;
 }
 
-/// pushIVUsers - Add all uses of Def to the current IV's worklist.
-///
+/// Add all uses of Def to the current IV's worklist.
 static void pushIVUsers(
   Instruction *Def,
   SmallPtrSet<Instruction*,16> &Simplified,
@@ -348,12 +462,12 @@ static void pushIVUsers(
     // Also ensure unique worklist users.
     // If Def is a LoopPhi, it may not be in the Simplified set, so check for
     // self edges first.
-    if (UI != Def && Simplified.insert(UI))
+    if (UI != Def && Simplified.insert(UI).second)
       SimpleIVUsers.push_back(std::make_pair(UI, Def));
   }
 }
 
-/// isSimpleIVUser - Return true if this instruction generates a simple SCEV
+/// Return true if this instruction generates a simple SCEV
 /// expression in terms of that IV.
 ///
 /// This is similar to IVUsers' isInteresting() but processes each instruction
@@ -374,7 +488,7 @@ static bool isSimpleIVUser(Instruction *I, const Loop *L, ScalarEvolution *SE) {
   return false;
 }
 
-/// simplifyUsers - Iteratively perform simplification on a worklist of users
+/// Iteratively perform simplification on a worklist of users
 /// of the specified induction variable. Each successive simplification may push
 /// more users which may themselves be candidates for simplification.
 ///
@@ -431,6 +545,16 @@ void SimplifyIndvar::simplifyUsers(PHINode *CurrIV, IVVisitor *V) {
       pushIVUsers(IVOperand, Simplified, SimpleIVUsers);
       continue;
     }
+
+    if (BinaryOperator *BO = dyn_cast<BinaryOperator>(UseOper.first)) {
+      if (isa<OverflowingBinaryOperator>(BO) &&
+          strengthenOverflowingOperation(BO, IVOperand)) {
+        // re-queue uses of the now modified binary operator and fall
+        // through to the checks that remain.
+        pushIVUsers(IVOperand, Simplified, SimpleIVUsers);
+      }
+    }
+
     CastInst *Cast = dyn_cast<CastInst>(UseOper.first);
     if (V && Cast) {
       V->visitCast(Cast);
@@ -446,7 +570,7 @@ namespace llvm {
 
 void IVVisitor::anchor() { }
 
-/// simplifyUsersOfIV - Simplify instructions that use this induction variable
+/// Simplify instructions that use this induction variable
 /// by using ScalarEvolution to analyze the IV's recurrence.
 bool simplifyUsersOfIV(PHINode *CurrIV, ScalarEvolution *SE, LPPassManager *LPM,
                        SmallVectorImpl<WeakVH> &Dead, IVVisitor *V)
@@ -457,7 +581,7 @@ bool simplifyUsersOfIV(PHINode *CurrIV, ScalarEvolution *SE, LPPassManager *LPM,
   return SIV.hasChanged();
 }
 
-/// simplifyLoopIVs - Simplify users of induction variables within this
+/// Simplify users of induction variables within this
 /// loop. This does not actually change or add IVs.
 bool simplifyLoopIVs(Loop *L, ScalarEvolution *SE, LPPassManager *LPM,
                      SmallVectorImpl<WeakVH> &Dead) {
diff --git a/lib/Transforms/Utils/SimplifyInstructions.cpp b/lib/Transforms/Utils/SimplifyInstructions.cpp
index 33b36378027d..cc97098d010a 100644
--- a/lib/Transforms/Utils/SimplifyInstructions.cpp
+++ b/lib/Transforms/Utils/SimplifyInstructions.cpp
@@ -18,6 +18,7 @@
 #include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/AssumptionCache.h"
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/Dominators.h"
@@ -41,6 +42,7 @@ namespace {
 
     void getAnalysisUsage(AnalysisUsage &AU) const override {
       AU.setPreservesCFG();
+      AU.addRequired<AssumptionCacheTracker>();
       AU.addRequired<TargetLibraryInfo>();
     }
 
@@ -52,6 +54,8 @@ namespace {
       DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
       const DataLayout *DL = DLP ? &DLP->getDataLayout() : nullptr;
       const TargetLibraryInfo *TLI = &getAnalysis<TargetLibraryInfo>();
+      AssumptionCache *AC =
+          &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
       SmallPtrSet<const Instruction*, 8> S1, S2, *ToSimplify = &S1, *Next = &S2;
       bool Changed = false;
 
@@ -68,7 +72,7 @@ namespace {
               continue;
             // Don't waste time simplifying unused instructions.
             if (!I->use_empty())
-              if (Value *V = SimplifyInstruction(I, DL, TLI, DT)) {
+              if (Value *V = SimplifyInstruction(I, DL, TLI, DT, AC)) {
                 // Mark all uses for resimplification next time round the loop.
                 for (User *U : I->users())
                   Next->insert(cast<Instruction>(U));
@@ -101,6 +105,7 @@ namespace {
 char InstSimplifier::ID = 0;
 INITIALIZE_PASS_BEGIN(InstSimplifier, "instsimplify",
                       "Remove redundant instructions", false, false)
+INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
 INITIALIZE_PASS_END(InstSimplifier, "instsimplify",
                     "Remove redundant instructions", false, false)
diff --git a/lib/Transforms/Utils/SimplifyLibCalls.cpp b/lib/Transforms/Utils/SimplifyLibCalls.cpp
index 3b61bb575a8d..5b4647ddcb5e 100644
--- a/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -27,65 +27,43 @@
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
+#include "llvm/IR/PatternMatch.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Target/TargetLibraryInfo.h"
 #include "llvm/Transforms/Utils/BuildLibCalls.h"
 
 using namespace llvm;
+using namespace PatternMatch;
 
 static cl::opt<bool>
-ColdErrorCalls("error-reporting-is-cold",  cl::init(true),
-  cl::Hidden, cl::desc("Treat error-reporting calls as cold"));
-
-/// This class is the abstract base class for the set of optimizations that
-/// corresponds to one library call.
-namespace {
-class LibCallOptimization {
-protected:
-  Function *Caller;
-  const DataLayout *DL;
-  const TargetLibraryInfo *TLI;
-  const LibCallSimplifier *LCS;
-  LLVMContext* Context;
-public:
-  LibCallOptimization() { }
-  virtual ~LibCallOptimization() {}
-
-  /// callOptimizer - This pure virtual method is implemented by base classes to
-  /// do various optimizations.  If this returns null then no transformation was
-  /// performed.  If it returns CI, then it transformed the call and CI is to be
-  /// deleted.  If it returns something else, replace CI with the new value and
-  /// delete CI.
-  virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B)
-    =0;
-
-  /// ignoreCallingConv - Returns false if this transformation could possibly
-  /// change the calling convention.
-  virtual bool ignoreCallingConv() { return false; }
-
-  Value *optimizeCall(CallInst *CI, const DataLayout *DL,
-                      const TargetLibraryInfo *TLI,
-                      const LibCallSimplifier *LCS, IRBuilder<> &B) {
-    Caller = CI->getParent()->getParent();
-    this->DL = DL;
-    this->TLI = TLI;
-    this->LCS = LCS;
-    if (CI->getCalledFunction())
-      Context = &CI->getCalledFunction()->getContext();
+    ColdErrorCalls("error-reporting-is-cold", cl::init(true), cl::Hidden,
+                   cl::desc("Treat error-reporting calls as cold"));
 
-    // We never change the calling convention.
-    if (!ignoreCallingConv() && CI->getCallingConv() != llvm::CallingConv::C)
-      return nullptr;
+static cl::opt<bool>
+    EnableUnsafeFPShrink("enable-double-float-shrink", cl::Hidden,
+                         cl::init(false),
+                         cl::desc("Enable unsafe double to float "
+                                  "shrinking for math lib calls"));
 
-    return callOptimizer(CI->getCalledFunction(), CI, B);
-  }
-};
 
 //===----------------------------------------------------------------------===//
 // Helper Functions
 //===----------------------------------------------------------------------===//
 
+static bool ignoreCallingConv(LibFunc::Func Func) {
+  switch (Func) {
+  case LibFunc::abs:
+  case LibFunc::labs:
+  case LibFunc::llabs:
+  case LibFunc::strlen:
+    return true;
+  default:
+    return false;
+  }
+  llvm_unreachable("All cases should be covered in the switch.");
+}
+
 /// isOnlyUsedInZeroEqualityComparison - Return true if it only matters that the
 /// value is equal or not-equal to zero.
 static bool isOnlyUsedInZeroEqualityComparison(Value *V) {
@@ -138,1908 +116,1739 @@ static bool hasUnaryFloatFn(const TargetLibraryInfo *TLI, Type *Ty,
   }
 }
 
-//===----------------------------------------------------------------------===//
-// Fortified Library Call Optimizations
-//===----------------------------------------------------------------------===//
-
-struct FortifiedLibCallOptimization : public LibCallOptimization {
-protected:
-  virtual bool isFoldable(unsigned SizeCIOp, unsigned SizeArgOp,
-			  bool isString) const = 0;
-};
-
-struct InstFortifiedLibCallOptimization : public FortifiedLibCallOptimization {
-  CallInst *CI;
-
-  bool isFoldable(unsigned SizeCIOp, unsigned SizeArgOp,
-                  bool isString) const override {
-    if (CI->getArgOperand(SizeCIOp) == CI->getArgOperand(SizeArgOp))
-      return true;
-    if (ConstantInt *SizeCI =
-                           dyn_cast<ConstantInt>(CI->getArgOperand(SizeCIOp))) {
-      if (SizeCI->isAllOnesValue())
-        return true;
-      if (isString) {
-        uint64_t Len = GetStringLength(CI->getArgOperand(SizeArgOp));
-        // If the length is 0 we don't know how long it is and so we can't
-        // remove the check.
-        if (Len == 0) return false;
-        return SizeCI->getZExtValue() >= Len;
-      }
-      if (ConstantInt *Arg = dyn_cast<ConstantInt>(
-                                                  CI->getArgOperand(SizeArgOp)))
-        return SizeCI->getZExtValue() >= Arg->getZExtValue();
-    }
+/// \brief Returns whether \p F matches the signature expected for the
+/// string/memory copying library function \p Func.
+/// Acceptable functions are st[rp][n]?cpy, memove, memcpy, and memset.
+/// Their fortified (_chk) counterparts are also accepted.
+static bool checkStringCopyLibFuncSignature(Function *F, LibFunc::Func Func,
+                                            const DataLayout *DL) {
+  FunctionType *FT = F->getFunctionType();
+  LLVMContext &Context = F->getContext();
+  Type *PCharTy = Type::getInt8PtrTy(Context);
+  Type *SizeTTy = DL ? DL->getIntPtrType(Context) : nullptr;
+  unsigned NumParams = FT->getNumParams();
+
+  // All string libfuncs return the same type as the first parameter.
+  if (FT->getReturnType() != FT->getParamType(0))
     return false;
-  }
-};
-
-struct MemCpyChkOpt : public InstFortifiedLibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    this->CI = CI;
-    FunctionType *FT = Callee->getFunctionType();
-    LLVMContext &Context = CI->getParent()->getContext();
-
-    // Check if this has the right signature.
-    if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
-        !FT->getParamType(0)->isPointerTy() ||
-        !FT->getParamType(1)->isPointerTy() ||
-        FT->getParamType(2) != DL->getIntPtrType(Context) ||
-        FT->getParamType(3) != DL->getIntPtrType(Context))
-      return nullptr;
 
-    if (isFoldable(3, 2, false)) {
-      B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
-                     CI->getArgOperand(2), 1);
-      return CI->getArgOperand(0);
-    }
-    return nullptr;
+  switch (Func) {
+  default:
+    llvm_unreachable("Can't check signature for non-string-copy libfunc.");
+  case LibFunc::stpncpy_chk:
+  case LibFunc::strncpy_chk:
+    --NumParams; // fallthrough
+  case LibFunc::stpncpy:
+  case LibFunc::strncpy: {
+    if (NumParams != 3 || FT->getParamType(0) != FT->getParamType(1) ||
+        FT->getParamType(0) != PCharTy || !FT->getParamType(2)->isIntegerTy())
+      return false;
+    break;
+  }
+  case LibFunc::strcpy_chk:
+  case LibFunc::stpcpy_chk:
+    --NumParams; // fallthrough
+  case LibFunc::stpcpy:
+  case LibFunc::strcpy: {
+    if (NumParams != 2 || FT->getParamType(0) != FT->getParamType(1) ||
+        FT->getParamType(0) != PCharTy)
+      return false;
+    break;
+  }
+  case LibFunc::memmove_chk:
+  case LibFunc::memcpy_chk:
+    --NumParams; // fallthrough
+  case LibFunc::memmove:
+  case LibFunc::memcpy: {
+    if (NumParams != 3 || !FT->getParamType(0)->isPointerTy() ||
+        !FT->getParamType(1)->isPointerTy() || FT->getParamType(2) != SizeTTy)
+      return false;
+    break;
   }
-};
-
-struct MemMoveChkOpt : public InstFortifiedLibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    this->CI = CI;
-    FunctionType *FT = Callee->getFunctionType();
-    LLVMContext &Context = CI->getParent()->getContext();
+  case LibFunc::memset_chk:
+    --NumParams; // fallthrough
+  case LibFunc::memset: {
+    if (NumParams != 3 || !FT->getParamType(0)->isPointerTy() ||
+        !FT->getParamType(1)->isIntegerTy() || FT->getParamType(2) != SizeTTy)
+      return false;
+    break;
+  }
+  }
+  // If this is a fortified libcall, the last parameter is a size_t.
+  if (NumParams == FT->getNumParams() - 1)
+    return FT->getParamType(FT->getNumParams() - 1) == SizeTTy;
+  return true;
+}
 
-    // Check if this has the right signature.
-    if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
-        !FT->getParamType(0)->isPointerTy() ||
-        !FT->getParamType(1)->isPointerTy() ||
-        FT->getParamType(2) != DL->getIntPtrType(Context) ||
-        FT->getParamType(3) != DL->getIntPtrType(Context))
-      return nullptr;
+//===----------------------------------------------------------------------===//
+// String and Memory Library Call Optimizations
+//===----------------------------------------------------------------------===//
 
-    if (isFoldable(3, 2, false)) {
-      B.CreateMemMove(CI->getArgOperand(0), CI->getArgOperand(1),
-                      CI->getArgOperand(2), 1);
-      return CI->getArgOperand(0);
-    }
+Value *LibCallSimplifier::optimizeStrCat(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  // Verify the "strcat" function prototype.
+  FunctionType *FT = Callee->getFunctionType();
+  if (FT->getNumParams() != 2||
+      FT->getReturnType() != B.getInt8PtrTy() ||
+      FT->getParamType(0) != FT->getReturnType() ||
+      FT->getParamType(1) != FT->getReturnType())
     return nullptr;
-  }
-};
 
-struct MemSetChkOpt : public InstFortifiedLibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    this->CI = CI;
-    FunctionType *FT = Callee->getFunctionType();
-    LLVMContext &Context = CI->getParent()->getContext();
-
-    // Check if this has the right signature.
-    if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
-        !FT->getParamType(0)->isPointerTy() ||
-        !FT->getParamType(1)->isIntegerTy() ||
-        FT->getParamType(2) != DL->getIntPtrType(Context) ||
-        FT->getParamType(3) != DL->getIntPtrType(Context))
-      return nullptr;
+  // Extract some information from the instruction
+  Value *Dst = CI->getArgOperand(0);
+  Value *Src = CI->getArgOperand(1);
 
-    if (isFoldable(3, 2, false)) {
-      Value *Val = B.CreateIntCast(CI->getArgOperand(1), B.getInt8Ty(),
-                                   false);
-      B.CreateMemSet(CI->getArgOperand(0), Val, CI->getArgOperand(2), 1);
-      return CI->getArgOperand(0);
-    }
+  // See if we can get the length of the input string.
+  uint64_t Len = GetStringLength(Src);
+  if (Len == 0)
     return nullptr;
-  }
-};
-
-struct StrCpyChkOpt : public InstFortifiedLibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    this->CI = CI;
-    StringRef Name = Callee->getName();
-    FunctionType *FT = Callee->getFunctionType();
-    LLVMContext &Context = CI->getParent()->getContext();
+  --Len; // Unbias length.
 
-    // Check if this has the right signature.
-    if (FT->getNumParams() != 3 ||
-        FT->getReturnType() != FT->getParamType(0) ||
-        FT->getParamType(0) != FT->getParamType(1) ||
-        FT->getParamType(0) != Type::getInt8PtrTy(Context) ||
-        FT->getParamType(2) != DL->getIntPtrType(Context))
-      return nullptr;
+  // Handle the simple, do-nothing case: strcat(x, "") -> x
+  if (Len == 0)
+    return Dst;
 
-    Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
-    if (Dst == Src)      // __strcpy_chk(x,x)  -> x
-      return Src;
-
-    // If a) we don't have any length information, or b) we know this will
-    // fit then just lower to a plain strcpy. Otherwise we'll keep our
-    // strcpy_chk call which may fail at runtime if the size is too long.
-    // TODO: It might be nice to get a maximum length out of the possible
-    // string lengths for varying.
-    if (isFoldable(2, 1, true)) {
-      Value *Ret = EmitStrCpy(Dst, Src, B, DL, TLI, Name.substr(2, 6));
-      return Ret;
-    } else {
-      // Maybe we can stil fold __strcpy_chk to __memcpy_chk.
-      uint64_t Len = GetStringLength(Src);
-      if (Len == 0) return nullptr;
-
-      // This optimization require DataLayout.
-      if (!DL) return nullptr;
-
-      Value *Ret =
-	EmitMemCpyChk(Dst, Src,
-                      ConstantInt::get(DL->getIntPtrType(Context), Len),
-                      CI->getArgOperand(2), B, DL, TLI);
-      return Ret;
-    }
+  // These optimizations require DataLayout.
+  if (!DL)
     return nullptr;
-  }
-};
 
-struct StpCpyChkOpt : public InstFortifiedLibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    this->CI = CI;
-    StringRef Name = Callee->getName();
-    FunctionType *FT = Callee->getFunctionType();
-    LLVMContext &Context = CI->getParent()->getContext();
+  return emitStrLenMemCpy(Src, Dst, Len, B);
+}
 
-    // Check if this has the right signature.
-    if (FT->getNumParams() != 3 ||
-        FT->getReturnType() != FT->getParamType(0) ||
-        FT->getParamType(0) != FT->getParamType(1) ||
-        FT->getParamType(0) != Type::getInt8PtrTy(Context) ||
-        FT->getParamType(2) != DL->getIntPtrType(FT->getParamType(0)))
-      return nullptr;
+Value *LibCallSimplifier::emitStrLenMemCpy(Value *Src, Value *Dst, uint64_t Len,
+                                           IRBuilder<> &B) {
+  // We need to find the end of the destination string.  That's where the
+  // memory is to be moved to. We just generate a call to strlen.
+  Value *DstLen = EmitStrLen(Dst, B, DL, TLI);
+  if (!DstLen)
+    return nullptr;
 
-    Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
-    if (Dst == Src) {  // stpcpy(x,x)  -> x+strlen(x)
-      Value *StrLen = EmitStrLen(Src, B, DL, TLI);
-      return StrLen ? B.CreateInBoundsGEP(Dst, StrLen) : nullptr;
-    }
+  // Now that we have the destination's length, we must index into the
+  // destination's pointer to get the actual memcpy destination (end of
+  // the string .. we're concatenating).
+  Value *CpyDst = B.CreateGEP(Dst, DstLen, "endptr");
+
+  // We have enough information to now generate the memcpy call to do the
+  // concatenation for us.  Make a memcpy to copy the nul byte with align = 1.
+  B.CreateMemCpy(
+      CpyDst, Src,
+      ConstantInt::get(DL->getIntPtrType(Src->getContext()), Len + 1), 1);
+  return Dst;
+}
 
-    // If a) we don't have any length information, or b) we know this will
-    // fit then just lower to a plain stpcpy. Otherwise we'll keep our
-    // stpcpy_chk call which may fail at runtime if the size is too long.
-    // TODO: It might be nice to get a maximum length out of the possible
-    // string lengths for varying.
-    if (isFoldable(2, 1, true)) {
-      Value *Ret = EmitStrCpy(Dst, Src, B, DL, TLI, Name.substr(2, 6));
-      return Ret;
-    } else {
-      // Maybe we can stil fold __stpcpy_chk to __memcpy_chk.
-      uint64_t Len = GetStringLength(Src);
-      if (Len == 0) return nullptr;
-
-      // This optimization require DataLayout.
-      if (!DL) return nullptr;
-
-      Type *PT = FT->getParamType(0);
-      Value *LenV = ConstantInt::get(DL->getIntPtrType(PT), Len);
-      Value *DstEnd = B.CreateGEP(Dst,
-                                  ConstantInt::get(DL->getIntPtrType(PT),
-                                                   Len - 1));
-      if (!EmitMemCpyChk(Dst, Src, LenV, CI->getArgOperand(2), B, DL, TLI))
-        return nullptr;
-      return DstEnd;
-    }
+Value *LibCallSimplifier::optimizeStrNCat(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  // Verify the "strncat" function prototype.
+  FunctionType *FT = Callee->getFunctionType();
+  if (FT->getNumParams() != 3 || FT->getReturnType() != B.getInt8PtrTy() ||
+      FT->getParamType(0) != FT->getReturnType() ||
+      FT->getParamType(1) != FT->getReturnType() ||
+      !FT->getParamType(2)->isIntegerTy())
     return nullptr;
-  }
-};
-
-struct StrNCpyChkOpt : public InstFortifiedLibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    this->CI = CI;
-    StringRef Name = Callee->getName();
-    FunctionType *FT = Callee->getFunctionType();
-    LLVMContext &Context = CI->getParent()->getContext();
 
-    // Check if this has the right signature.
-    if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
-        FT->getParamType(0) != FT->getParamType(1) ||
-        FT->getParamType(0) != Type::getInt8PtrTy(Context) ||
-        !FT->getParamType(2)->isIntegerTy() ||
-        FT->getParamType(3) != DL->getIntPtrType(Context))
-      return nullptr;
+  // Extract some information from the instruction
+  Value *Dst = CI->getArgOperand(0);
+  Value *Src = CI->getArgOperand(1);
+  uint64_t Len;
 
-    if (isFoldable(3, 2, false)) {
-      Value *Ret = EmitStrNCpy(CI->getArgOperand(0), CI->getArgOperand(1),
-                               CI->getArgOperand(2), B, DL, TLI,
-                               Name.substr(2, 7));
-      return Ret;
-    }
+  // We don't do anything if length is not constant
+  if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getArgOperand(2)))
+    Len = LengthArg->getZExtValue();
+  else
     return nullptr;
-  }
-};
 
-//===----------------------------------------------------------------------===//
-// String and Memory Library Call Optimizations
-//===----------------------------------------------------------------------===//
+  // See if we can get the length of the input string.
+  uint64_t SrcLen = GetStringLength(Src);
+  if (SrcLen == 0)
+    return nullptr;
+  --SrcLen; // Unbias length.
 
-struct StrCatOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    // Verify the "strcat" function prototype.
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 2 ||
-        FT->getReturnType() != B.getInt8PtrTy() ||
-        FT->getParamType(0) != FT->getReturnType() ||
-        FT->getParamType(1) != FT->getReturnType())
-      return nullptr;
+  // Handle the simple, do-nothing cases:
+  // strncat(x, "", c) -> x
+  // strncat(x,  c, 0) -> x
+  if (SrcLen == 0 || Len == 0)
+    return Dst;
 
-    // Extract some information from the instruction
-    Value *Dst = CI->getArgOperand(0);
-    Value *Src = CI->getArgOperand(1);
+  // These optimizations require DataLayout.
+  if (!DL)
+    return nullptr;
 
-    // See if we can get the length of the input string.
-    uint64_t Len = GetStringLength(Src);
-    if (Len == 0) return nullptr;
-    --Len;  // Unbias length.
+  // We don't optimize this case
+  if (Len < SrcLen)
+    return nullptr;
 
-    // Handle the simple, do-nothing case: strcat(x, "") -> x
-    if (Len == 0)
-      return Dst;
+  // strncat(x, s, c) -> strcat(x, s)
+  // s is constant so the strcat can be optimized further
+  return emitStrLenMemCpy(Src, Dst, SrcLen, B);
+}
 
-    // These optimizations require DataLayout.
-    if (!DL) return nullptr;
+Value *LibCallSimplifier::optimizeStrChr(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  // Verify the "strchr" function prototype.
+  FunctionType *FT = Callee->getFunctionType();
+  if (FT->getNumParams() != 2 || FT->getReturnType() != B.getInt8PtrTy() ||
+      FT->getParamType(0) != FT->getReturnType() ||
+      !FT->getParamType(1)->isIntegerTy(32))
+    return nullptr;
 
-    return emitStrLenMemCpy(Src, Dst, Len, B);
-  }
+  Value *SrcStr = CI->getArgOperand(0);
 
-  Value *emitStrLenMemCpy(Value *Src, Value *Dst, uint64_t Len,
-                          IRBuilder<> &B) {
-    // We need to find the end of the destination string.  That's where the
-    // memory is to be moved to. We just generate a call to strlen.
-    Value *DstLen = EmitStrLen(Dst, B, DL, TLI);
-    if (!DstLen)
+  // If the second operand is non-constant, see if we can compute the length
+  // of the input string and turn this into memchr.
+  ConstantInt *CharC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
+  if (!CharC) {
+    // These optimizations require DataLayout.
+    if (!DL)
       return nullptr;
 
-    // Now that we have the destination's length, we must index into the
-    // destination's pointer to get the actual memcpy destination (end of
-    // the string .. we're concatenating).
-    Value *CpyDst = B.CreateGEP(Dst, DstLen, "endptr");
+    uint64_t Len = GetStringLength(SrcStr);
+    if (Len == 0 || !FT->getParamType(1)->isIntegerTy(32)) // memchr needs i32.
+      return nullptr;
 
-    // We have enough information to now generate the memcpy call to do the
-    // concatenation for us.  Make a memcpy to copy the nul byte with align = 1.
-    B.CreateMemCpy(CpyDst, Src,
-                   ConstantInt::get(DL->getIntPtrType(*Context), Len + 1), 1);
-    return Dst;
+    return EmitMemChr(
+        SrcStr, CI->getArgOperand(1), // include nul.
+        ConstantInt::get(DL->getIntPtrType(CI->getContext()), Len), B, DL, TLI);
   }
-};
-
-struct StrNCatOpt : public StrCatOpt {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    // Verify the "strncat" function prototype.
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 3 ||
-        FT->getReturnType() != B.getInt8PtrTy() ||
-        FT->getParamType(0) != FT->getReturnType() ||
-        FT->getParamType(1) != FT->getReturnType() ||
-        !FT->getParamType(2)->isIntegerTy())
-      return nullptr;
 
-    // Extract some information from the instruction
-    Value *Dst = CI->getArgOperand(0);
-    Value *Src = CI->getArgOperand(1);
-    uint64_t Len;
+  // Otherwise, the character is a constant, see if the first argument is
+  // a string literal.  If so, we can constant fold.
+  StringRef Str;
+  if (!getConstantStringInfo(SrcStr, Str)) {
+    if (DL && CharC->isZero()) // strchr(p, 0) -> p + strlen(p)
+      return B.CreateGEP(SrcStr, EmitStrLen(SrcStr, B, DL, TLI), "strchr");
+    return nullptr;
+  }
 
-    // We don't do anything if length is not constant
-    if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getArgOperand(2)))
-      Len = LengthArg->getZExtValue();
-    else
-      return nullptr;
+  // Compute the offset, make sure to handle the case when we're searching for
+  // zero (a weird way to spell strlen).
+  size_t I = (0xFF & CharC->getSExtValue()) == 0
+                 ? Str.size()
+                 : Str.find(CharC->getSExtValue());
+  if (I == StringRef::npos) // Didn't find the char.  strchr returns null.
+    return Constant::getNullValue(CI->getType());
 
-    // See if we can get the length of the input string.
-    uint64_t SrcLen = GetStringLength(Src);
-    if (SrcLen == 0) return nullptr;
-    --SrcLen;  // Unbias length.
+  // strchr(s+n,c)  -> gep(s+n+i,c)
+  return B.CreateGEP(SrcStr, B.getInt64(I), "strchr");
+}
 
-    // Handle the simple, do-nothing cases:
-    // strncat(x, "", c) -> x
-    // strncat(x,  c, 0) -> x
-    if (SrcLen == 0 || Len == 0) return Dst;
+Value *LibCallSimplifier::optimizeStrRChr(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  // Verify the "strrchr" function prototype.
+  FunctionType *FT = Callee->getFunctionType();
+  if (FT->getNumParams() != 2 || FT->getReturnType() != B.getInt8PtrTy() ||
+      FT->getParamType(0) != FT->getReturnType() ||
+      !FT->getParamType(1)->isIntegerTy(32))
+    return nullptr;
 
-    // These optimizations require DataLayout.
-    if (!DL) return nullptr;
-
-    // We don't optimize this case
-    if (Len < SrcLen) return nullptr;
-
-    // strncat(x, s, c) -> strcat(x, s)
-    // s is constant so the strcat can be optimized further
-    return emitStrLenMemCpy(Src, Dst, SrcLen, B);
-  }
-};
-
-struct StrChrOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    // Verify the "strchr" function prototype.
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 2 ||
-        FT->getReturnType() != B.getInt8PtrTy() ||
-        FT->getParamType(0) != FT->getReturnType() ||
-        !FT->getParamType(1)->isIntegerTy(32))
-      return nullptr;
+  Value *SrcStr = CI->getArgOperand(0);
+  ConstantInt *CharC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
 
-    Value *SrcStr = CI->getArgOperand(0);
+  // Cannot fold anything if we're not looking for a constant.
+  if (!CharC)
+    return nullptr;
 
-    // If the second operand is non-constant, see if we can compute the length
-    // of the input string and turn this into memchr.
-    ConstantInt *CharC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
-    if (!CharC) {
-      // These optimizations require DataLayout.
-      if (!DL) return nullptr;
+  StringRef Str;
+  if (!getConstantStringInfo(SrcStr, Str)) {
+    // strrchr(s, 0) -> strchr(s, 0)
+    if (DL && CharC->isZero())
+      return EmitStrChr(SrcStr, '\0', B, DL, TLI);
+    return nullptr;
+  }
 
-      uint64_t Len = GetStringLength(SrcStr);
-      if (Len == 0 || !FT->getParamType(1)->isIntegerTy(32))// memchr needs i32.
-        return nullptr;
+  // Compute the offset.
+  size_t I = (0xFF & CharC->getSExtValue()) == 0
+                 ? Str.size()
+                 : Str.rfind(CharC->getSExtValue());
+  if (I == StringRef::npos) // Didn't find the char. Return null.
+    return Constant::getNullValue(CI->getType());
 
-      return EmitMemChr(SrcStr, CI->getArgOperand(1), // include nul.
-                        ConstantInt::get(DL->getIntPtrType(*Context), Len),
-                        B, DL, TLI);
-    }
+  // strrchr(s+n,c) -> gep(s+n+i,c)
+  return B.CreateGEP(SrcStr, B.getInt64(I), "strrchr");
+}
 
-    // Otherwise, the character is a constant, see if the first argument is
-    // a string literal.  If so, we can constant fold.
-    StringRef Str;
-    if (!getConstantStringInfo(SrcStr, Str)) {
-      if (DL && CharC->isZero()) // strchr(p, 0) -> p + strlen(p)
-        return B.CreateGEP(SrcStr, EmitStrLen(SrcStr, B, DL, TLI), "strchr");
-      return nullptr;
-    }
+Value *LibCallSimplifier::optimizeStrCmp(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  // Verify the "strcmp" function prototype.
+  FunctionType *FT = Callee->getFunctionType();
+  if (FT->getNumParams() != 2 || !FT->getReturnType()->isIntegerTy(32) ||
+      FT->getParamType(0) != FT->getParamType(1) ||
+      FT->getParamType(0) != B.getInt8PtrTy())
+    return nullptr;
 
-    // Compute the offset, make sure to handle the case when we're searching for
-    // zero (a weird way to spell strlen).
-    size_t I = (0xFF & CharC->getSExtValue()) == 0 ?
-        Str.size() : Str.find(CharC->getSExtValue());
-    if (I == StringRef::npos) // Didn't find the char.  strchr returns null.
-      return Constant::getNullValue(CI->getType());
+  Value *Str1P = CI->getArgOperand(0), *Str2P = CI->getArgOperand(1);
+  if (Str1P == Str2P) // strcmp(x,x)  -> 0
+    return ConstantInt::get(CI->getType(), 0);
 
-    // strchr(s+n,c)  -> gep(s+n+i,c)
-    return B.CreateGEP(SrcStr, B.getInt64(I), "strchr");
-  }
-};
+  StringRef Str1, Str2;
+  bool HasStr1 = getConstantStringInfo(Str1P, Str1);
+  bool HasStr2 = getConstantStringInfo(Str2P, Str2);
 
-struct StrRChrOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    // Verify the "strrchr" function prototype.
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 2 ||
-        FT->getReturnType() != B.getInt8PtrTy() ||
-        FT->getParamType(0) != FT->getReturnType() ||
-        !FT->getParamType(1)->isIntegerTy(32))
-      return nullptr;
+  // strcmp(x, y)  -> cnst  (if both x and y are constant strings)
+  if (HasStr1 && HasStr2)
+    return ConstantInt::get(CI->getType(), Str1.compare(Str2));
 
-    Value *SrcStr = CI->getArgOperand(0);
-    ConstantInt *CharC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
+  if (HasStr1 && Str1.empty()) // strcmp("", x) -> -*x
+    return B.CreateNeg(
+        B.CreateZExt(B.CreateLoad(Str2P, "strcmpload"), CI->getType()));
 
-    // Cannot fold anything if we're not looking for a constant.
-    if (!CharC)
-      return nullptr;
+  if (HasStr2 && Str2.empty()) // strcmp(x,"") -> *x
+    return B.CreateZExt(B.CreateLoad(Str1P, "strcmpload"), CI->getType());
 
-    StringRef Str;
-    if (!getConstantStringInfo(SrcStr, Str)) {
-      // strrchr(s, 0) -> strchr(s, 0)
-      if (DL && CharC->isZero())
-        return EmitStrChr(SrcStr, '\0', B, DL, TLI);
+  // strcmp(P, "x") -> memcmp(P, "x", 2)
+  uint64_t Len1 = GetStringLength(Str1P);
+  uint64_t Len2 = GetStringLength(Str2P);
+  if (Len1 && Len2) {
+    // These optimizations require DataLayout.
+    if (!DL)
       return nullptr;
-    }
-
-    // Compute the offset.
-    size_t I = (0xFF & CharC->getSExtValue()) == 0 ?
-        Str.size() : Str.rfind(CharC->getSExtValue());
-    if (I == StringRef::npos) // Didn't find the char. Return null.
-      return Constant::getNullValue(CI->getType());
 
-    // strrchr(s+n,c) -> gep(s+n+i,c)
-    return B.CreateGEP(SrcStr, B.getInt64(I), "strrchr");
+    return EmitMemCmp(Str1P, Str2P,
+                      ConstantInt::get(DL->getIntPtrType(CI->getContext()),
+                                       std::min(Len1, Len2)),
+                      B, DL, TLI);
   }
-};
-
-struct StrCmpOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    // Verify the "strcmp" function prototype.
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 2 ||
-        !FT->getReturnType()->isIntegerTy(32) ||
-        FT->getParamType(0) != FT->getParamType(1) ||
-        FT->getParamType(0) != B.getInt8PtrTy())
-      return nullptr;
 
-    Value *Str1P = CI->getArgOperand(0), *Str2P = CI->getArgOperand(1);
-    if (Str1P == Str2P)      // strcmp(x,x)  -> 0
-      return ConstantInt::get(CI->getType(), 0);
+  return nullptr;
+}
 
-    StringRef Str1, Str2;
-    bool HasStr1 = getConstantStringInfo(Str1P, Str1);
-    bool HasStr2 = getConstantStringInfo(Str2P, Str2);
+Value *LibCallSimplifier::optimizeStrNCmp(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  // Verify the "strncmp" function prototype.
+  FunctionType *FT = Callee->getFunctionType();
+  if (FT->getNumParams() != 3 || !FT->getReturnType()->isIntegerTy(32) ||
+      FT->getParamType(0) != FT->getParamType(1) ||
+      FT->getParamType(0) != B.getInt8PtrTy() ||
+      !FT->getParamType(2)->isIntegerTy())
+    return nullptr;
 
-    // strcmp(x, y)  -> cnst  (if both x and y are constant strings)
-    if (HasStr1 && HasStr2)
-      return ConstantInt::get(CI->getType(), Str1.compare(Str2));
+  Value *Str1P = CI->getArgOperand(0), *Str2P = CI->getArgOperand(1);
+  if (Str1P == Str2P) // strncmp(x,x,n)  -> 0
+    return ConstantInt::get(CI->getType(), 0);
 
-    if (HasStr1 && Str1.empty()) // strcmp("", x) -> -*x
-      return B.CreateNeg(B.CreateZExt(B.CreateLoad(Str2P, "strcmpload"),
-                                      CI->getType()));
+  // Get the length argument if it is constant.
+  uint64_t Length;
+  if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getArgOperand(2)))
+    Length = LengthArg->getZExtValue();
+  else
+    return nullptr;
 
-    if (HasStr2 && Str2.empty()) // strcmp(x,"") -> *x
-      return B.CreateZExt(B.CreateLoad(Str1P, "strcmpload"), CI->getType());
+  if (Length == 0) // strncmp(x,y,0)   -> 0
+    return ConstantInt::get(CI->getType(), 0);
 
-    // strcmp(P, "x") -> memcmp(P, "x", 2)
-    uint64_t Len1 = GetStringLength(Str1P);
-    uint64_t Len2 = GetStringLength(Str2P);
-    if (Len1 && Len2) {
-      // These optimizations require DataLayout.
-      if (!DL) return nullptr;
+  if (DL && Length == 1) // strncmp(x,y,1) -> memcmp(x,y,1)
+    return EmitMemCmp(Str1P, Str2P, CI->getArgOperand(2), B, DL, TLI);
 
-      return EmitMemCmp(Str1P, Str2P,
-                        ConstantInt::get(DL->getIntPtrType(*Context),
-                        std::min(Len1, Len2)), B, DL, TLI);
-    }
+  StringRef Str1, Str2;
+  bool HasStr1 = getConstantStringInfo(Str1P, Str1);
+  bool HasStr2 = getConstantStringInfo(Str2P, Str2);
 
-    return nullptr;
+  // strncmp(x, y)  -> cnst  (if both x and y are constant strings)
+  if (HasStr1 && HasStr2) {
+    StringRef SubStr1 = Str1.substr(0, Length);
+    StringRef SubStr2 = Str2.substr(0, Length);
+    return ConstantInt::get(CI->getType(), SubStr1.compare(SubStr2));
   }
-};
 
-struct StrNCmpOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    // Verify the "strncmp" function prototype.
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 3 ||
-        !FT->getReturnType()->isIntegerTy(32) ||
-        FT->getParamType(0) != FT->getParamType(1) ||
-        FT->getParamType(0) != B.getInt8PtrTy() ||
-        !FT->getParamType(2)->isIntegerTy())
-      return nullptr;
+  if (HasStr1 && Str1.empty()) // strncmp("", x, n) -> -*x
+    return B.CreateNeg(
+        B.CreateZExt(B.CreateLoad(Str2P, "strcmpload"), CI->getType()));
 
-    Value *Str1P = CI->getArgOperand(0), *Str2P = CI->getArgOperand(1);
-    if (Str1P == Str2P)      // strncmp(x,x,n)  -> 0
-      return ConstantInt::get(CI->getType(), 0);
-
-    // Get the length argument if it is constant.
-    uint64_t Length;
-    if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getArgOperand(2)))
-      Length = LengthArg->getZExtValue();
-    else
-      return nullptr;
+  if (HasStr2 && Str2.empty()) // strncmp(x, "", n) -> *x
+    return B.CreateZExt(B.CreateLoad(Str1P, "strcmpload"), CI->getType());
 
-    if (Length == 0) // strncmp(x,y,0)   -> 0
-      return ConstantInt::get(CI->getType(), 0);
-
-    if (DL && Length == 1) // strncmp(x,y,1) -> memcmp(x,y,1)
-      return EmitMemCmp(Str1P, Str2P, CI->getArgOperand(2), B, DL, TLI);
+  return nullptr;
+}
 
-    StringRef Str1, Str2;
-    bool HasStr1 = getConstantStringInfo(Str1P, Str1);
-    bool HasStr2 = getConstantStringInfo(Str2P, Str2);
+Value *LibCallSimplifier::optimizeStrCpy(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
 
-    // strncmp(x, y)  -> cnst  (if both x and y are constant strings)
-    if (HasStr1 && HasStr2) {
-      StringRef SubStr1 = Str1.substr(0, Length);
-      StringRef SubStr2 = Str2.substr(0, Length);
-      return ConstantInt::get(CI->getType(), SubStr1.compare(SubStr2));
-    }
+  if (!checkStringCopyLibFuncSignature(Callee, LibFunc::strcpy, DL))
+    return nullptr;
 
-    if (HasStr1 && Str1.empty())  // strncmp("", x, n) -> -*x
-      return B.CreateNeg(B.CreateZExt(B.CreateLoad(Str2P, "strcmpload"),
-                                      CI->getType()));
+  Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
+  if (Dst == Src) // strcpy(x,x)  -> x
+    return Src;
 
-    if (HasStr2 && Str2.empty())  // strncmp(x, "", n) -> *x
-      return B.CreateZExt(B.CreateLoad(Str1P, "strcmpload"), CI->getType());
+  // These optimizations require DataLayout.
+  if (!DL)
+    return nullptr;
 
+  // See if we can get the length of the input string.
+  uint64_t Len = GetStringLength(Src);
+  if (Len == 0)
     return nullptr;
-  }
-};
 
-struct StrCpyOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    // Verify the "strcpy" function prototype.
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 2 ||
-        FT->getReturnType() != FT->getParamType(0) ||
-        FT->getParamType(0) != FT->getParamType(1) ||
-        FT->getParamType(0) != B.getInt8PtrTy())
-      return nullptr;
+  // We have enough information to now generate the memcpy call to do the
+  // copy for us.  Make a memcpy to copy the nul byte with align = 1.
+  B.CreateMemCpy(Dst, Src,
+                 ConstantInt::get(DL->getIntPtrType(CI->getContext()), Len), 1);
+  return Dst;
+}
 
-    Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
-    if (Dst == Src)      // strcpy(x,x)  -> x
-      return Src;
+Value *LibCallSimplifier::optimizeStpCpy(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  // Verify the "stpcpy" function prototype.
+  FunctionType *FT = Callee->getFunctionType();
 
-    // These optimizations require DataLayout.
-    if (!DL) return nullptr;
+  if (!checkStringCopyLibFuncSignature(Callee, LibFunc::stpcpy, DL))
+    return nullptr;
 
-    // See if we can get the length of the input string.
-    uint64_t Len = GetStringLength(Src);
-    if (Len == 0) return nullptr;
+  // These optimizations require DataLayout.
+  if (!DL)
+    return nullptr;
 
-    // We have enough information to now generate the memcpy call to do the
-    // copy for us.  Make a memcpy to copy the nul byte with align = 1.
-    B.CreateMemCpy(Dst, Src,
-		   ConstantInt::get(DL->getIntPtrType(*Context), Len), 1);
-    return Dst;
+  Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
+  if (Dst == Src) { // stpcpy(x,x)  -> x+strlen(x)
+    Value *StrLen = EmitStrLen(Src, B, DL, TLI);
+    return StrLen ? B.CreateInBoundsGEP(Dst, StrLen) : nullptr;
   }
-};
-
-struct StpCpyOpt: public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    // Verify the "stpcpy" function prototype.
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 2 ||
-        FT->getReturnType() != FT->getParamType(0) ||
-        FT->getParamType(0) != FT->getParamType(1) ||
-        FT->getParamType(0) != B.getInt8PtrTy())
-      return nullptr;
-
-    // These optimizations require DataLayout.
-    if (!DL) return nullptr;
-
-    Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
-    if (Dst == Src) {  // stpcpy(x,x)  -> x+strlen(x)
-      Value *StrLen = EmitStrLen(Src, B, DL, TLI);
-      return StrLen ? B.CreateInBoundsGEP(Dst, StrLen) : nullptr;
-    }
-
-    // See if we can get the length of the input string.
-    uint64_t Len = GetStringLength(Src);
-    if (Len == 0) return nullptr;
-
-    Type *PT = FT->getParamType(0);
-    Value *LenV = ConstantInt::get(DL->getIntPtrType(PT), Len);
-    Value *DstEnd = B.CreateGEP(Dst,
-                                ConstantInt::get(DL->getIntPtrType(PT),
-                                                 Len - 1));
-
-    // We have enough information to now generate the memcpy call to do the
-    // copy for us.  Make a memcpy to copy the nul byte with align = 1.
-    B.CreateMemCpy(Dst, Src, LenV, 1);
-    return DstEnd;
-  }
-};
-
-struct StrNCpyOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
-        FT->getParamType(0) != FT->getParamType(1) ||
-        FT->getParamType(0) != B.getInt8PtrTy() ||
-        !FT->getParamType(2)->isIntegerTy())
-      return nullptr;
-
-    Value *Dst = CI->getArgOperand(0);
-    Value *Src = CI->getArgOperand(1);
-    Value *LenOp = CI->getArgOperand(2);
 
-    // See if we can get the length of the input string.
-    uint64_t SrcLen = GetStringLength(Src);
-    if (SrcLen == 0) return nullptr;
-    --SrcLen;
+  // See if we can get the length of the input string.
+  uint64_t Len = GetStringLength(Src);
+  if (Len == 0)
+    return nullptr;
 
-    if (SrcLen == 0) {
-      // strncpy(x, "", y) -> memset(x, '\0', y, 1)
-      B.CreateMemSet(Dst, B.getInt8('\0'), LenOp, 1);
-      return Dst;
-    }
+  Type *PT = FT->getParamType(0);
+  Value *LenV = ConstantInt::get(DL->getIntPtrType(PT), Len);
+  Value *DstEnd =
+      B.CreateGEP(Dst, ConstantInt::get(DL->getIntPtrType(PT), Len - 1));
 
-    uint64_t Len;
-    if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(LenOp))
-      Len = LengthArg->getZExtValue();
-    else
-      return nullptr;
+  // We have enough information to now generate the memcpy call to do the
+  // copy for us.  Make a memcpy to copy the nul byte with align = 1.
+  B.CreateMemCpy(Dst, Src, LenV, 1);
+  return DstEnd;
+}
 
-    if (Len == 0) return Dst; // strncpy(x, y, 0) -> x
+Value *LibCallSimplifier::optimizeStrNCpy(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  FunctionType *FT = Callee->getFunctionType();
 
-    // These optimizations require DataLayout.
-    if (!DL) return nullptr;
+  if (!checkStringCopyLibFuncSignature(Callee, LibFunc::strncpy, DL))
+    return nullptr;
 
-    // Let strncpy handle the zero padding
-    if (Len > SrcLen+1) return nullptr;
+  Value *Dst = CI->getArgOperand(0);
+  Value *Src = CI->getArgOperand(1);
+  Value *LenOp = CI->getArgOperand(2);
 
-    Type *PT = FT->getParamType(0);
-    // strncpy(x, s, c) -> memcpy(x, s, c, 1) [s and c are constant]
-    B.CreateMemCpy(Dst, Src,
-                   ConstantInt::get(DL->getIntPtrType(PT), Len), 1);
+  // See if we can get the length of the input string.
+  uint64_t SrcLen = GetStringLength(Src);
+  if (SrcLen == 0)
+    return nullptr;
+  --SrcLen;
 
+  if (SrcLen == 0) {
+    // strncpy(x, "", y) -> memset(x, '\0', y, 1)
+    B.CreateMemSet(Dst, B.getInt8('\0'), LenOp, 1);
     return Dst;
   }
-};
-
-struct StrLenOpt : public LibCallOptimization {
-  bool ignoreCallingConv() override { return true; }
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 1 ||
-        FT->getParamType(0) != B.getInt8PtrTy() ||
-        !FT->getReturnType()->isIntegerTy())
-      return nullptr;
 
-    Value *Src = CI->getArgOperand(0);
-
-    // Constant folding: strlen("xyz") -> 3
-    if (uint64_t Len = GetStringLength(Src))
-      return ConstantInt::get(CI->getType(), Len-1);
-
-    // strlen(x?"foo":"bars") --> x ? 3 : 4
-    if (SelectInst *SI = dyn_cast<SelectInst>(Src)) {
-      uint64_t LenTrue = GetStringLength(SI->getTrueValue());
-      uint64_t LenFalse = GetStringLength(SI->getFalseValue());
-      if (LenTrue && LenFalse) {
-        emitOptimizationRemark(*Context, "simplify-libcalls", *Caller,
-                               SI->getDebugLoc(),
-                               "folded strlen(select) to select of constants");
-        return B.CreateSelect(SI->getCondition(),
-                              ConstantInt::get(CI->getType(), LenTrue-1),
-                              ConstantInt::get(CI->getType(), LenFalse-1));
-      }
-    }
+  uint64_t Len;
+  if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(LenOp))
+    Len = LengthArg->getZExtValue();
+  else
+    return nullptr;
 
-    // strlen(x) != 0 --> *x != 0
-    // strlen(x) == 0 --> *x == 0
-    if (isOnlyUsedInZeroEqualityComparison(CI))
-      return B.CreateZExt(B.CreateLoad(Src, "strlenfirst"), CI->getType());
+  if (Len == 0)
+    return Dst; // strncpy(x, y, 0) -> x
 
+  // These optimizations require DataLayout.
+  if (!DL)
     return nullptr;
-  }
-};
 
-struct StrPBrkOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 2 ||
-        FT->getParamType(0) != B.getInt8PtrTy() ||
-        FT->getParamType(1) != FT->getParamType(0) ||
-        FT->getReturnType() != FT->getParamType(0))
-      return nullptr;
+  // Let strncpy handle the zero padding
+  if (Len > SrcLen + 1)
+    return nullptr;
 
-    StringRef S1, S2;
-    bool HasS1 = getConstantStringInfo(CI->getArgOperand(0), S1);
-    bool HasS2 = getConstantStringInfo(CI->getArgOperand(1), S2);
+  Type *PT = FT->getParamType(0);
+  // strncpy(x, s, c) -> memcpy(x, s, c, 1) [s and c are constant]
+  B.CreateMemCpy(Dst, Src, ConstantInt::get(DL->getIntPtrType(PT), Len), 1);
 
-    // strpbrk(s, "") -> NULL
-    // strpbrk("", s) -> NULL
-    if ((HasS1 && S1.empty()) || (HasS2 && S2.empty()))
-      return Constant::getNullValue(CI->getType());
+  return Dst;
+}
 
-    // Constant folding.
-    if (HasS1 && HasS2) {
-      size_t I = S1.find_first_of(S2);
-      if (I == StringRef::npos) // No match.
-        return Constant::getNullValue(CI->getType());
+Value *LibCallSimplifier::optimizeStrLen(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  FunctionType *FT = Callee->getFunctionType();
+  if (FT->getNumParams() != 1 || FT->getParamType(0) != B.getInt8PtrTy() ||
+      !FT->getReturnType()->isIntegerTy())
+    return nullptr;
 
-      return B.CreateGEP(CI->getArgOperand(0), B.getInt64(I), "strpbrk");
+  Value *Src = CI->getArgOperand(0);
+
+  // Constant folding: strlen("xyz") -> 3
+  if (uint64_t Len = GetStringLength(Src))
+    return ConstantInt::get(CI->getType(), Len - 1);
+
+  // strlen(x?"foo":"bars") --> x ? 3 : 4
+  if (SelectInst *SI = dyn_cast<SelectInst>(Src)) {
+    uint64_t LenTrue = GetStringLength(SI->getTrueValue());
+    uint64_t LenFalse = GetStringLength(SI->getFalseValue());
+    if (LenTrue && LenFalse) {
+      Function *Caller = CI->getParent()->getParent();
+      emitOptimizationRemark(CI->getContext(), "simplify-libcalls", *Caller,
+                             SI->getDebugLoc(),
+                             "folded strlen(select) to select of constants");
+      return B.CreateSelect(SI->getCondition(),
+                            ConstantInt::get(CI->getType(), LenTrue - 1),
+                            ConstantInt::get(CI->getType(), LenFalse - 1));
     }
-
-    // strpbrk(s, "a") -> strchr(s, 'a')
-    if (DL && HasS2 && S2.size() == 1)
-      return EmitStrChr(CI->getArgOperand(0), S2[0], B, DL, TLI);
-
-    return nullptr;
   }
-};
 
-struct StrToOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    FunctionType *FT = Callee->getFunctionType();
-    if ((FT->getNumParams() != 2 && FT->getNumParams() != 3) ||
-        !FT->getParamType(0)->isPointerTy() ||
-        !FT->getParamType(1)->isPointerTy())
-      return nullptr;
+  // strlen(x) != 0 --> *x != 0
+  // strlen(x) == 0 --> *x == 0
+  if (isOnlyUsedInZeroEqualityComparison(CI))
+    return B.CreateZExt(B.CreateLoad(Src, "strlenfirst"), CI->getType());
 
-    Value *EndPtr = CI->getArgOperand(1);
-    if (isa<ConstantPointerNull>(EndPtr)) {
-      // With a null EndPtr, this function won't capture the main argument.
-      // It would be readonly too, except that it still may write to errno.
-      CI->addAttribute(1, Attribute::NoCapture);
-    }
+  return nullptr;
+}
 
+Value *LibCallSimplifier::optimizeStrPBrk(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  FunctionType *FT = Callee->getFunctionType();
+  if (FT->getNumParams() != 2 || FT->getParamType(0) != B.getInt8PtrTy() ||
+      FT->getParamType(1) != FT->getParamType(0) ||
+      FT->getReturnType() != FT->getParamType(0))
     return nullptr;
-  }
-};
 
-struct StrSpnOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 2 ||
-        FT->getParamType(0) != B.getInt8PtrTy() ||
-        FT->getParamType(1) != FT->getParamType(0) ||
-        !FT->getReturnType()->isIntegerTy())
-      return nullptr;
+  StringRef S1, S2;
+  bool HasS1 = getConstantStringInfo(CI->getArgOperand(0), S1);
+  bool HasS2 = getConstantStringInfo(CI->getArgOperand(1), S2);
 
-    StringRef S1, S2;
-    bool HasS1 = getConstantStringInfo(CI->getArgOperand(0), S1);
-    bool HasS2 = getConstantStringInfo(CI->getArgOperand(1), S2);
+  // strpbrk(s, "") -> nullptr
+  // strpbrk("", s) -> nullptr
+  if ((HasS1 && S1.empty()) || (HasS2 && S2.empty()))
+    return Constant::getNullValue(CI->getType());
 
-    // strspn(s, "") -> 0
-    // strspn("", s) -> 0
-    if ((HasS1 && S1.empty()) || (HasS2 && S2.empty()))
+  // Constant folding.
+  if (HasS1 && HasS2) {
+    size_t I = S1.find_first_of(S2);
+    if (I == StringRef::npos) // No match.
       return Constant::getNullValue(CI->getType());
 
-    // Constant folding.
-    if (HasS1 && HasS2) {
-      size_t Pos = S1.find_first_not_of(S2);
-      if (Pos == StringRef::npos) Pos = S1.size();
-      return ConstantInt::get(CI->getType(), Pos);
-    }
-
-    return nullptr;
+    return B.CreateGEP(CI->getArgOperand(0), B.getInt64(I), "strpbrk");
   }
-};
 
-struct StrCSpnOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 2 ||
-        FT->getParamType(0) != B.getInt8PtrTy() ||
-        FT->getParamType(1) != FT->getParamType(0) ||
-        !FT->getReturnType()->isIntegerTy())
-      return nullptr;
+  // strpbrk(s, "a") -> strchr(s, 'a')
+  if (DL && HasS2 && S2.size() == 1)
+    return EmitStrChr(CI->getArgOperand(0), S2[0], B, DL, TLI);
 
-    StringRef S1, S2;
-    bool HasS1 = getConstantStringInfo(CI->getArgOperand(0), S1);
-    bool HasS2 = getConstantStringInfo(CI->getArgOperand(1), S2);
+  return nullptr;
+}
 
-    // strcspn("", s) -> 0
-    if (HasS1 && S1.empty())
-      return Constant::getNullValue(CI->getType());
+Value *LibCallSimplifier::optimizeStrTo(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  FunctionType *FT = Callee->getFunctionType();
+  if ((FT->getNumParams() != 2 && FT->getNumParams() != 3) ||
+      !FT->getParamType(0)->isPointerTy() ||
+      !FT->getParamType(1)->isPointerTy())
+    return nullptr;
 
-    // Constant folding.
-    if (HasS1 && HasS2) {
-      size_t Pos = S1.find_first_of(S2);
-      if (Pos == StringRef::npos) Pos = S1.size();
-      return ConstantInt::get(CI->getType(), Pos);
-    }
+  Value *EndPtr = CI->getArgOperand(1);
+  if (isa<ConstantPointerNull>(EndPtr)) {
+    // With a null EndPtr, this function won't capture the main argument.
+    // It would be readonly too, except that it still may write to errno.
+    CI->addAttribute(1, Attribute::NoCapture);
+  }
 
-    // strcspn(s, "") -> strlen(s)
-    if (DL && HasS2 && S2.empty())
-      return EmitStrLen(CI->getArgOperand(0), B, DL, TLI);
+  return nullptr;
+}
 
+Value *LibCallSimplifier::optimizeStrSpn(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  FunctionType *FT = Callee->getFunctionType();
+  if (FT->getNumParams() != 2 || FT->getParamType(0) != B.getInt8PtrTy() ||
+      FT->getParamType(1) != FT->getParamType(0) ||
+      !FT->getReturnType()->isIntegerTy())
     return nullptr;
+
+  StringRef S1, S2;
+  bool HasS1 = getConstantStringInfo(CI->getArgOperand(0), S1);
+  bool HasS2 = getConstantStringInfo(CI->getArgOperand(1), S2);
+
+  // strspn(s, "") -> 0
+  // strspn("", s) -> 0
+  if ((HasS1 && S1.empty()) || (HasS2 && S2.empty()))
+    return Constant::getNullValue(CI->getType());
+
+  // Constant folding.
+  if (HasS1 && HasS2) {
+    size_t Pos = S1.find_first_not_of(S2);
+    if (Pos == StringRef::npos)
+      Pos = S1.size();
+    return ConstantInt::get(CI->getType(), Pos);
   }
-};
 
-struct StrStrOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 2 ||
-        !FT->getParamType(0)->isPointerTy() ||
-        !FT->getParamType(1)->isPointerTy() ||
-        !FT->getReturnType()->isPointerTy())
-      return nullptr;
+  return nullptr;
+}
 
-    // fold strstr(x, x) -> x.
-    if (CI->getArgOperand(0) == CI->getArgOperand(1))
-      return B.CreateBitCast(CI->getArgOperand(0), CI->getType());
+Value *LibCallSimplifier::optimizeStrCSpn(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  FunctionType *FT = Callee->getFunctionType();
+  if (FT->getNumParams() != 2 || FT->getParamType(0) != B.getInt8PtrTy() ||
+      FT->getParamType(1) != FT->getParamType(0) ||
+      !FT->getReturnType()->isIntegerTy())
+    return nullptr;
 
-    // fold strstr(a, b) == a -> strncmp(a, b, strlen(b)) == 0
-    if (DL && isOnlyUsedInEqualityComparison(CI, CI->getArgOperand(0))) {
-      Value *StrLen = EmitStrLen(CI->getArgOperand(1), B, DL, TLI);
-      if (!StrLen)
-        return nullptr;
-      Value *StrNCmp = EmitStrNCmp(CI->getArgOperand(0), CI->getArgOperand(1),
-                                   StrLen, B, DL, TLI);
-      if (!StrNCmp)
-        return nullptr;
-      for (auto UI = CI->user_begin(), UE = CI->user_end(); UI != UE;) {
-        ICmpInst *Old = cast<ICmpInst>(*UI++);
-        Value *Cmp = B.CreateICmp(Old->getPredicate(), StrNCmp,
-                                  ConstantInt::getNullValue(StrNCmp->getType()),
-                                  "cmp");
-        LCS->replaceAllUsesWith(Old, Cmp);
-      }
-      return CI;
-    }
+  StringRef S1, S2;
+  bool HasS1 = getConstantStringInfo(CI->getArgOperand(0), S1);
+  bool HasS2 = getConstantStringInfo(CI->getArgOperand(1), S2);
 
-    // See if either input string is a constant string.
-    StringRef SearchStr, ToFindStr;
-    bool HasStr1 = getConstantStringInfo(CI->getArgOperand(0), SearchStr);
-    bool HasStr2 = getConstantStringInfo(CI->getArgOperand(1), ToFindStr);
+  // strcspn("", s) -> 0
+  if (HasS1 && S1.empty())
+    return Constant::getNullValue(CI->getType());
 
-    // fold strstr(x, "") -> x.
-    if (HasStr2 && ToFindStr.empty())
-      return B.CreateBitCast(CI->getArgOperand(0), CI->getType());
+  // Constant folding.
+  if (HasS1 && HasS2) {
+    size_t Pos = S1.find_first_of(S2);
+    if (Pos == StringRef::npos)
+      Pos = S1.size();
+    return ConstantInt::get(CI->getType(), Pos);
+  }
 
-    // If both strings are known, constant fold it.
-    if (HasStr1 && HasStr2) {
-      size_t Offset = SearchStr.find(ToFindStr);
+  // strcspn(s, "") -> strlen(s)
+  if (DL && HasS2 && S2.empty())
+    return EmitStrLen(CI->getArgOperand(0), B, DL, TLI);
 
-      if (Offset == StringRef::npos) // strstr("foo", "bar") -> null
-        return Constant::getNullValue(CI->getType());
+  return nullptr;
+}
 
-      // strstr("abcd", "bc") -> gep((char*)"abcd", 1)
-      Value *Result = CastToCStr(CI->getArgOperand(0), B);
-      Result = B.CreateConstInBoundsGEP1_64(Result, Offset, "strstr");
-      return B.CreateBitCast(Result, CI->getType());
-    }
+Value *LibCallSimplifier::optimizeStrStr(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  FunctionType *FT = Callee->getFunctionType();
+  if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
+      !FT->getParamType(1)->isPointerTy() ||
+      !FT->getReturnType()->isPointerTy())
+    return nullptr;
+
+  // fold strstr(x, x) -> x.
+  if (CI->getArgOperand(0) == CI->getArgOperand(1))
+    return B.CreateBitCast(CI->getArgOperand(0), CI->getType());
 
-    // fold strstr(x, "y") -> strchr(x, 'y').
-    if (HasStr2 && ToFindStr.size() == 1) {
-      Value *StrChr= EmitStrChr(CI->getArgOperand(0), ToFindStr[0], B, DL, TLI);
-      return StrChr ? B.CreateBitCast(StrChr, CI->getType()) : nullptr;
+  // fold strstr(a, b) == a -> strncmp(a, b, strlen(b)) == 0
+  if (DL && isOnlyUsedInEqualityComparison(CI, CI->getArgOperand(0))) {
+    Value *StrLen = EmitStrLen(CI->getArgOperand(1), B, DL, TLI);
+    if (!StrLen)
+      return nullptr;
+    Value *StrNCmp = EmitStrNCmp(CI->getArgOperand(0), CI->getArgOperand(1),
+                                 StrLen, B, DL, TLI);
+    if (!StrNCmp)
+      return nullptr;
+    for (auto UI = CI->user_begin(), UE = CI->user_end(); UI != UE;) {
+      ICmpInst *Old = cast<ICmpInst>(*UI++);
+      Value *Cmp =
+          B.CreateICmp(Old->getPredicate(), StrNCmp,
+                       ConstantInt::getNullValue(StrNCmp->getType()), "cmp");
+      replaceAllUsesWith(Old, Cmp);
     }
-    return nullptr;
+    return CI;
   }
-};
 
-struct MemCmpOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 3 || !FT->getParamType(0)->isPointerTy() ||
-        !FT->getParamType(1)->isPointerTy() ||
-        !FT->getReturnType()->isIntegerTy(32))
-      return nullptr;
+  // See if either input string is a constant string.
+  StringRef SearchStr, ToFindStr;
+  bool HasStr1 = getConstantStringInfo(CI->getArgOperand(0), SearchStr);
+  bool HasStr2 = getConstantStringInfo(CI->getArgOperand(1), ToFindStr);
+
+  // fold strstr(x, "") -> x.
+  if (HasStr2 && ToFindStr.empty())
+    return B.CreateBitCast(CI->getArgOperand(0), CI->getType());
 
-    Value *LHS = CI->getArgOperand(0), *RHS = CI->getArgOperand(1);
+  // If both strings are known, constant fold it.
+  if (HasStr1 && HasStr2) {
+    size_t Offset = SearchStr.find(ToFindStr);
 
-    if (LHS == RHS)  // memcmp(s,s,x) -> 0
+    if (Offset == StringRef::npos) // strstr("foo", "bar") -> null
       return Constant::getNullValue(CI->getType());
 
-    // Make sure we have a constant length.
-    ConstantInt *LenC = dyn_cast<ConstantInt>(CI->getArgOperand(2));
-    if (!LenC) return nullptr;
-    uint64_t Len = LenC->getZExtValue();
+    // strstr("abcd", "bc") -> gep((char*)"abcd", 1)
+    Value *Result = CastToCStr(CI->getArgOperand(0), B);
+    Result = B.CreateConstInBoundsGEP1_64(Result, Offset, "strstr");
+    return B.CreateBitCast(Result, CI->getType());
+  }
 
-    if (Len == 0) // memcmp(s1,s2,0) -> 0
-      return Constant::getNullValue(CI->getType());
+  // fold strstr(x, "y") -> strchr(x, 'y').
+  if (HasStr2 && ToFindStr.size() == 1) {
+    Value *StrChr = EmitStrChr(CI->getArgOperand(0), ToFindStr[0], B, DL, TLI);
+    return StrChr ? B.CreateBitCast(StrChr, CI->getType()) : nullptr;
+  }
+  return nullptr;
+}
 
-    // memcmp(S1,S2,1) -> *(unsigned char*)LHS - *(unsigned char*)RHS
-    if (Len == 1) {
-      Value *LHSV = B.CreateZExt(B.CreateLoad(CastToCStr(LHS, B), "lhsc"),
-                                 CI->getType(), "lhsv");
-      Value *RHSV = B.CreateZExt(B.CreateLoad(CastToCStr(RHS, B), "rhsc"),
-                                 CI->getType(), "rhsv");
-      return B.CreateSub(LHSV, RHSV, "chardiff");
-    }
+Value *LibCallSimplifier::optimizeMemCmp(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  FunctionType *FT = Callee->getFunctionType();
+  if (FT->getNumParams() != 3 || !FT->getParamType(0)->isPointerTy() ||
+      !FT->getParamType(1)->isPointerTy() ||
+      !FT->getReturnType()->isIntegerTy(32))
+    return nullptr;
 
-    // Constant folding: memcmp(x, y, l) -> cnst (all arguments are constant)
-    StringRef LHSStr, RHSStr;
-    if (getConstantStringInfo(LHS, LHSStr) &&
-        getConstantStringInfo(RHS, RHSStr)) {
-      // Make sure we're not reading out-of-bounds memory.
-      if (Len > LHSStr.size() || Len > RHSStr.size())
-        return nullptr;
-      // Fold the memcmp and normalize the result.  This way we get consistent
-      // results across multiple platforms.
-      uint64_t Ret = 0;
-      int Cmp = memcmp(LHSStr.data(), RHSStr.data(), Len);
-      if (Cmp < 0)
-        Ret = -1;
-      else if (Cmp > 0)
-        Ret = 1;
-      return ConstantInt::get(CI->getType(), Ret);
-    }
+  Value *LHS = CI->getArgOperand(0), *RHS = CI->getArgOperand(1);
 
+  if (LHS == RHS) // memcmp(s,s,x) -> 0
+    return Constant::getNullValue(CI->getType());
+
+  // Make sure we have a constant length.
+  ConstantInt *LenC = dyn_cast<ConstantInt>(CI->getArgOperand(2));
+  if (!LenC)
     return nullptr;
+  uint64_t Len = LenC->getZExtValue();
+
+  if (Len == 0) // memcmp(s1,s2,0) -> 0
+    return Constant::getNullValue(CI->getType());
+
+  // memcmp(S1,S2,1) -> *(unsigned char*)LHS - *(unsigned char*)RHS
+  if (Len == 1) {
+    Value *LHSV = B.CreateZExt(B.CreateLoad(CastToCStr(LHS, B), "lhsc"),
+                               CI->getType(), "lhsv");
+    Value *RHSV = B.CreateZExt(B.CreateLoad(CastToCStr(RHS, B), "rhsc"),
+                               CI->getType(), "rhsv");
+    return B.CreateSub(LHSV, RHSV, "chardiff");
+  }
+
+  // Constant folding: memcmp(x, y, l) -> cnst (all arguments are constant)
+  StringRef LHSStr, RHSStr;
+  if (getConstantStringInfo(LHS, LHSStr) &&
+      getConstantStringInfo(RHS, RHSStr)) {
+    // Make sure we're not reading out-of-bounds memory.
+    if (Len > LHSStr.size() || Len > RHSStr.size())
+      return nullptr;
+    // Fold the memcmp and normalize the result.  This way we get consistent
+    // results across multiple platforms.
+    uint64_t Ret = 0;
+    int Cmp = memcmp(LHSStr.data(), RHSStr.data(), Len);
+    if (Cmp < 0)
+      Ret = -1;
+    else if (Cmp > 0)
+      Ret = 1;
+    return ConstantInt::get(CI->getType(), Ret);
   }
-};
 
-struct MemCpyOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    // These optimizations require DataLayout.
-    if (!DL) return nullptr;
+  return nullptr;
+}
 
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
-        !FT->getParamType(0)->isPointerTy() ||
-        !FT->getParamType(1)->isPointerTy() ||
-        FT->getParamType(2) != DL->getIntPtrType(*Context))
-      return nullptr;
+Value *LibCallSimplifier::optimizeMemCpy(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  // These optimizations require DataLayout.
+  if (!DL)
+    return nullptr;
 
-    // memcpy(x, y, n) -> llvm.memcpy(x, y, n, 1)
-    B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
-                   CI->getArgOperand(2), 1);
-    return CI->getArgOperand(0);
-  }
-};
+  if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memcpy, DL))
+    return nullptr;
 
-struct MemMoveOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    // These optimizations require DataLayout.
-    if (!DL) return nullptr;
+  // memcpy(x, y, n) -> llvm.memcpy(x, y, n, 1)
+  B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
+                 CI->getArgOperand(2), 1);
+  return CI->getArgOperand(0);
+}
 
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
-        !FT->getParamType(0)->isPointerTy() ||
-        !FT->getParamType(1)->isPointerTy() ||
-        FT->getParamType(2) != DL->getIntPtrType(*Context))
-      return nullptr;
+Value *LibCallSimplifier::optimizeMemMove(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  // These optimizations require DataLayout.
+  if (!DL)
+    return nullptr;
 
-    // memmove(x, y, n) -> llvm.memmove(x, y, n, 1)
-    B.CreateMemMove(CI->getArgOperand(0), CI->getArgOperand(1),
-                    CI->getArgOperand(2), 1);
-    return CI->getArgOperand(0);
-  }
-};
+  if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memmove, DL))
+    return nullptr;
 
-struct MemSetOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    // These optimizations require DataLayout.
-    if (!DL) return nullptr;
+  // memmove(x, y, n) -> llvm.memmove(x, y, n, 1)
+  B.CreateMemMove(CI->getArgOperand(0), CI->getArgOperand(1),
+                  CI->getArgOperand(2), 1);
+  return CI->getArgOperand(0);
+}
 
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
-        !FT->getParamType(0)->isPointerTy() ||
-        !FT->getParamType(1)->isIntegerTy() ||
-        FT->getParamType(2) != DL->getIntPtrType(FT->getParamType(0)))
-      return nullptr;
+Value *LibCallSimplifier::optimizeMemSet(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  // These optimizations require DataLayout.
+  if (!DL)
+    return nullptr;
 
-    // memset(p, v, n) -> llvm.memset(p, v, n, 1)
-    Value *Val = B.CreateIntCast(CI->getArgOperand(1), B.getInt8Ty(), false);
-    B.CreateMemSet(CI->getArgOperand(0), Val, CI->getArgOperand(2), 1);
-    return CI->getArgOperand(0);
-  }
-};
+  if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memset, DL))
+    return nullptr;
+
+  // memset(p, v, n) -> llvm.memset(p, v, n, 1)
+  Value *Val = B.CreateIntCast(CI->getArgOperand(1), B.getInt8Ty(), false);
+  B.CreateMemSet(CI->getArgOperand(0), Val, CI->getArgOperand(2), 1);
+  return CI->getArgOperand(0);
+}
 
 //===----------------------------------------------------------------------===//
 // Math Library Optimizations
 //===----------------------------------------------------------------------===//
 
+/// Return a variant of Val with float type.
+/// Currently this works in two cases: If Val is an FPExtension of a float
+/// value to something bigger, simply return the operand.
+/// If Val is a ConstantFP but can be converted to a float ConstantFP without
+/// loss of precision do so.
+static Value *valueHasFloatPrecision(Value *Val) {
+  if (FPExtInst *Cast = dyn_cast<FPExtInst>(Val)) {
+    Value *Op = Cast->getOperand(0);
+    if (Op->getType()->isFloatTy())
+      return Op;
+  }
+  if (ConstantFP *Const = dyn_cast<ConstantFP>(Val)) {
+    APFloat F = Const->getValueAPF();
+    bool losesInfo;
+    (void)F.convert(APFloat::IEEEsingle, APFloat::rmNearestTiesToEven,
+                    &losesInfo);
+    if (!losesInfo)
+      return ConstantFP::get(Const->getContext(), F);
+  }
+  return nullptr;
+}
+
 //===----------------------------------------------------------------------===//
 // Double -> Float Shrinking Optimizations for Unary Functions like 'floor'
 
-struct UnaryDoubleFPOpt : public LibCallOptimization {
-  bool CheckRetType;
-  UnaryDoubleFPOpt(bool CheckReturnType): CheckRetType(CheckReturnType) {}
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 1 || !FT->getReturnType()->isDoubleTy() ||
-        !FT->getParamType(0)->isDoubleTy())
-      return nullptr;
+Value *LibCallSimplifier::optimizeUnaryDoubleFP(CallInst *CI, IRBuilder<> &B,
+                                                bool CheckRetType) {
+  Function *Callee = CI->getCalledFunction();
+  FunctionType *FT = Callee->getFunctionType();
+  if (FT->getNumParams() != 1 || !FT->getReturnType()->isDoubleTy() ||
+      !FT->getParamType(0)->isDoubleTy())
+    return nullptr;
 
-    if (CheckRetType) {
-      // Check if all the uses for function like 'sin' are converted to float.
-      for (User *U : CI->users()) {
-        FPTruncInst *Cast = dyn_cast<FPTruncInst>(U);
-        if (!Cast || !Cast->getType()->isFloatTy())
-          return nullptr;
-      }
+  if (CheckRetType) {
+    // Check if all the uses for function like 'sin' are converted to float.
+    for (User *U : CI->users()) {
+      FPTruncInst *Cast = dyn_cast<FPTruncInst>(U);
+      if (!Cast || !Cast->getType()->isFloatTy())
+        return nullptr;
     }
+  }
 
-    // If this is something like 'floor((double)floatval)', convert to floorf.
-    FPExtInst *Cast = dyn_cast<FPExtInst>(CI->getArgOperand(0));
-    if (!Cast || !Cast->getOperand(0)->getType()->isFloatTy())
-      return nullptr;
+  // If this is something like 'floor((double)floatval)', convert to floorf.
+  Value *V = valueHasFloatPrecision(CI->getArgOperand(0));
+  if (V == nullptr)
+    return nullptr;
 
-    // floor((double)floatval) -> (double)floorf(floatval)
-    Value *V = Cast->getOperand(0);
+  // floor((double)floatval) -> (double)floorf(floatval)
+  if (Callee->isIntrinsic()) {
+    Module *M = CI->getParent()->getParent()->getParent();
+    Intrinsic::ID IID = (Intrinsic::ID) Callee->getIntrinsicID();
+    Function *F = Intrinsic::getDeclaration(M, IID, B.getFloatTy());
+    V = B.CreateCall(F, V);
+  } else {
+    // The call is a library call rather than an intrinsic.
     V = EmitUnaryFloatFnCall(V, Callee->getName(), B, Callee->getAttributes());
-    return B.CreateFPExt(V, B.getDoubleTy());
   }
-};
+
+  return B.CreateFPExt(V, B.getDoubleTy());
+}
 
 // Double -> Float Shrinking Optimizations for Binary Functions like 'fmin/fmax'
-struct BinaryDoubleFPOpt : public LibCallOptimization {
-  bool CheckRetType;
-  BinaryDoubleFPOpt(bool CheckReturnType): CheckRetType(CheckReturnType) {}
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    FunctionType *FT = Callee->getFunctionType();
-    // Just make sure this has 2 arguments of the same FP type, which match the
-    // result type.
-    if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) ||
-        FT->getParamType(0) != FT->getParamType(1) ||
-        !FT->getParamType(0)->isFloatingPointTy())
-      return nullptr;
+Value *LibCallSimplifier::optimizeBinaryDoubleFP(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  FunctionType *FT = Callee->getFunctionType();
+  // Just make sure this has 2 arguments of the same FP type, which match the
+  // result type.
+  if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) ||
+      FT->getParamType(0) != FT->getParamType(1) ||
+      !FT->getParamType(0)->isFloatingPointTy())
+    return nullptr;
 
-    if (CheckRetType) {
-      // Check if all the uses for function like 'fmin/fmax' are converted to
-      // float.
-      for (User *U : CI->users()) {
-        FPTruncInst *Cast = dyn_cast<FPTruncInst>(U);
-        if (!Cast || !Cast->getType()->isFloatTy())
-          return nullptr;
-      }
-    }
+  // If this is something like 'fmin((double)floatval1, (double)floatval2)',
+  // or fmin(1.0, (double)floatval), then we convert it to fminf.
+  Value *V1 = valueHasFloatPrecision(CI->getArgOperand(0));
+  if (V1 == nullptr)
+    return nullptr;
+  Value *V2 = valueHasFloatPrecision(CI->getArgOperand(1));
+  if (V2 == nullptr)
+    return nullptr;
 
-    // If this is something like 'fmin((double)floatval1, (double)floatval2)',
-    // we convert it to fminf.
-    FPExtInst *Cast1 = dyn_cast<FPExtInst>(CI->getArgOperand(0));
-    FPExtInst *Cast2 = dyn_cast<FPExtInst>(CI->getArgOperand(1));
-    if (!Cast1 || !Cast1->getOperand(0)->getType()->isFloatTy() ||
-        !Cast2 || !Cast2->getOperand(0)->getType()->isFloatTy())
-      return nullptr;
+  // fmin((double)floatval1, (double)floatval2)
+  //                      -> (double)fminf(floatval1, floatval2)
+  // TODO: Handle intrinsics in the same way as in optimizeUnaryDoubleFP().
+  Value *V = EmitBinaryFloatFnCall(V1, V2, Callee->getName(), B,
+                                   Callee->getAttributes());
+  return B.CreateFPExt(V, B.getDoubleTy());
+}
 
-    // fmin((double)floatval1, (double)floatval2)
-    //                      -> (double)fmin(floatval1, floatval2)
-    Value *V = nullptr;
-    Value *V1 = Cast1->getOperand(0);
-    Value *V2 = Cast2->getOperand(0);
-    V = EmitBinaryFloatFnCall(V1, V2, Callee->getName(), B,
-                              Callee->getAttributes());
-    return B.CreateFPExt(V, B.getDoubleTy());
-  }
-};
-
-struct UnsafeFPLibCallOptimization : public LibCallOptimization {
-  bool UnsafeFPShrink;
-  UnsafeFPLibCallOptimization(bool UnsafeFPShrink) {
-    this->UnsafeFPShrink = UnsafeFPShrink;
-  }
-};
-
-struct CosOpt : public UnsafeFPLibCallOptimization {
-  CosOpt(bool UnsafeFPShrink) : UnsafeFPLibCallOptimization(UnsafeFPShrink) {}
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    Value *Ret = nullptr;
-    if (UnsafeFPShrink && Callee->getName() == "cos" &&
-        TLI->has(LibFunc::cosf)) {
-      UnaryDoubleFPOpt UnsafeUnaryDoubleFP(true);
-      Ret = UnsafeUnaryDoubleFP.callOptimizer(Callee, CI, B);
-    }
+Value *LibCallSimplifier::optimizeCos(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  Value *Ret = nullptr;
+  if (UnsafeFPShrink && Callee->getName() == "cos" && TLI->has(LibFunc::cosf)) {
+    Ret = optimizeUnaryDoubleFP(CI, B, true);
+  }
 
-    FunctionType *FT = Callee->getFunctionType();
-    // Just make sure this has 1 argument of FP type, which matches the
-    // result type.
-    if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
-        !FT->getParamType(0)->isFloatingPointTy())
-      return Ret;
+  FunctionType *FT = Callee->getFunctionType();
+  // Just make sure this has 1 argument of FP type, which matches the
+  // result type.
+  if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
+      !FT->getParamType(0)->isFloatingPointTy())
+    return Ret;
 
-    // cos(-x) -> cos(x)
-    Value *Op1 = CI->getArgOperand(0);
-    if (BinaryOperator::isFNeg(Op1)) {
-      BinaryOperator *BinExpr = cast<BinaryOperator>(Op1);
-      return B.CreateCall(Callee, BinExpr->getOperand(1), "cos");
-    }
+  // cos(-x) -> cos(x)
+  Value *Op1 = CI->getArgOperand(0);
+  if (BinaryOperator::isFNeg(Op1)) {
+    BinaryOperator *BinExpr = cast<BinaryOperator>(Op1);
+    return B.CreateCall(Callee, BinExpr->getOperand(1), "cos");
+  }
+  return Ret;
+}
+
+Value *LibCallSimplifier::optimizePow(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+
+  Value *Ret = nullptr;
+  if (UnsafeFPShrink && Callee->getName() == "pow" && TLI->has(LibFunc::powf)) {
+    Ret = optimizeUnaryDoubleFP(CI, B, true);
+  }
+
+  FunctionType *FT = Callee->getFunctionType();
+  // Just make sure this has 2 arguments of the same FP type, which match the
+  // result type.
+  if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) ||
+      FT->getParamType(0) != FT->getParamType(1) ||
+      !FT->getParamType(0)->isFloatingPointTy())
     return Ret;
+
+  Value *Op1 = CI->getArgOperand(0), *Op2 = CI->getArgOperand(1);
+  if (ConstantFP *Op1C = dyn_cast<ConstantFP>(Op1)) {
+    // pow(1.0, x) -> 1.0
+    if (Op1C->isExactlyValue(1.0))
+      return Op1C;
+    // pow(2.0, x) -> exp2(x)
+    if (Op1C->isExactlyValue(2.0) &&
+        hasUnaryFloatFn(TLI, Op1->getType(), LibFunc::exp2, LibFunc::exp2f,
+                        LibFunc::exp2l))
+      return EmitUnaryFloatFnCall(Op2, "exp2", B, Callee->getAttributes());
+    // pow(10.0, x) -> exp10(x)
+    if (Op1C->isExactlyValue(10.0) &&
+        hasUnaryFloatFn(TLI, Op1->getType(), LibFunc::exp10, LibFunc::exp10f,
+                        LibFunc::exp10l))
+      return EmitUnaryFloatFnCall(Op2, TLI->getName(LibFunc::exp10), B,
+                                  Callee->getAttributes());
+  }
+
+  ConstantFP *Op2C = dyn_cast<ConstantFP>(Op2);
+  if (!Op2C)
+    return Ret;
+
+  if (Op2C->getValueAPF().isZero()) // pow(x, 0.0) -> 1.0
+    return ConstantFP::get(CI->getType(), 1.0);
+
+  if (Op2C->isExactlyValue(0.5) &&
+      hasUnaryFloatFn(TLI, Op2->getType(), LibFunc::sqrt, LibFunc::sqrtf,
+                      LibFunc::sqrtl) &&
+      hasUnaryFloatFn(TLI, Op2->getType(), LibFunc::fabs, LibFunc::fabsf,
+                      LibFunc::fabsl)) {
+    // Expand pow(x, 0.5) to (x == -infinity ? +infinity : fabs(sqrt(x))).
+    // This is faster than calling pow, and still handles negative zero
+    // and negative infinity correctly.
+    // TODO: In fast-math mode, this could be just sqrt(x).
+    // TODO: In finite-only mode, this could be just fabs(sqrt(x)).
+    Value *Inf = ConstantFP::getInfinity(CI->getType());
+    Value *NegInf = ConstantFP::getInfinity(CI->getType(), true);
+    Value *Sqrt = EmitUnaryFloatFnCall(Op1, "sqrt", B, Callee->getAttributes());
+    Value *FAbs =
+        EmitUnaryFloatFnCall(Sqrt, "fabs", B, Callee->getAttributes());
+    Value *FCmp = B.CreateFCmpOEQ(Op1, NegInf);
+    Value *Sel = B.CreateSelect(FCmp, Inf, FAbs);
+    return Sel;
+  }
+
+  if (Op2C->isExactlyValue(1.0)) // pow(x, 1.0) -> x
+    return Op1;
+  if (Op2C->isExactlyValue(2.0)) // pow(x, 2.0) -> x*x
+    return B.CreateFMul(Op1, Op1, "pow2");
+  if (Op2C->isExactlyValue(-1.0)) // pow(x, -1.0) -> 1.0/x
+    return B.CreateFDiv(ConstantFP::get(CI->getType(), 1.0), Op1, "powrecip");
+  return nullptr;
+}
+
+Value *LibCallSimplifier::optimizeExp2(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  Function *Caller = CI->getParent()->getParent();
+
+  Value *Ret = nullptr;
+  if (UnsafeFPShrink && Callee->getName() == "exp2" &&
+      TLI->has(LibFunc::exp2f)) {
+    Ret = optimizeUnaryDoubleFP(CI, B, true);
   }
-};
-
-struct PowOpt : public UnsafeFPLibCallOptimization {
-  PowOpt(bool UnsafeFPShrink) : UnsafeFPLibCallOptimization(UnsafeFPShrink) {}
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    Value *Ret = nullptr;
-    if (UnsafeFPShrink && Callee->getName() == "pow" &&
-        TLI->has(LibFunc::powf)) {
-      UnaryDoubleFPOpt UnsafeUnaryDoubleFP(true);
-      Ret = UnsafeUnaryDoubleFP.callOptimizer(Callee, CI, B);
-    }
 
-    FunctionType *FT = Callee->getFunctionType();
-    // Just make sure this has 2 arguments of the same FP type, which match the
-    // result type.
-    if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) ||
-        FT->getParamType(0) != FT->getParamType(1) ||
-        !FT->getParamType(0)->isFloatingPointTy())
-      return Ret;
+  FunctionType *FT = Callee->getFunctionType();
+  // Just make sure this has 1 argument of FP type, which matches the
+  // result type.
+  if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
+      !FT->getParamType(0)->isFloatingPointTy())
+    return Ret;
 
-    Value *Op1 = CI->getArgOperand(0), *Op2 = CI->getArgOperand(1);
-    if (ConstantFP *Op1C = dyn_cast<ConstantFP>(Op1)) {
-      // pow(1.0, x) -> 1.0
-      if (Op1C->isExactlyValue(1.0))
-        return Op1C;
-      // pow(2.0, x) -> exp2(x)
-      if (Op1C->isExactlyValue(2.0) &&
-          hasUnaryFloatFn(TLI, Op1->getType(), LibFunc::exp2, LibFunc::exp2f,
-                          LibFunc::exp2l))
-        return EmitUnaryFloatFnCall(Op2, "exp2", B, Callee->getAttributes());
-      // pow(10.0, x) -> exp10(x)
-      if (Op1C->isExactlyValue(10.0) &&
-          hasUnaryFloatFn(TLI, Op1->getType(), LibFunc::exp10, LibFunc::exp10f,
-                          LibFunc::exp10l))
-        return EmitUnaryFloatFnCall(Op2, TLI->getName(LibFunc::exp10), B,
-                                    Callee->getAttributes());
+  Value *Op = CI->getArgOperand(0);
+  // Turn exp2(sitofp(x)) -> ldexp(1.0, sext(x))  if sizeof(x) <= 32
+  // Turn exp2(uitofp(x)) -> ldexp(1.0, zext(x))  if sizeof(x) < 32
+  LibFunc::Func LdExp = LibFunc::ldexpl;
+  if (Op->getType()->isFloatTy())
+    LdExp = LibFunc::ldexpf;
+  else if (Op->getType()->isDoubleTy())
+    LdExp = LibFunc::ldexp;
+
+  if (TLI->has(LdExp)) {
+    Value *LdExpArg = nullptr;
+    if (SIToFPInst *OpC = dyn_cast<SIToFPInst>(Op)) {
+      if (OpC->getOperand(0)->getType()->getPrimitiveSizeInBits() <= 32)
+        LdExpArg = B.CreateSExt(OpC->getOperand(0), B.getInt32Ty());
+    } else if (UIToFPInst *OpC = dyn_cast<UIToFPInst>(Op)) {
+      if (OpC->getOperand(0)->getType()->getPrimitiveSizeInBits() < 32)
+        LdExpArg = B.CreateZExt(OpC->getOperand(0), B.getInt32Ty());
     }
 
-    ConstantFP *Op2C = dyn_cast<ConstantFP>(Op2);
-    if (!Op2C) return Ret;
-
-    if (Op2C->getValueAPF().isZero())  // pow(x, 0.0) -> 1.0
-      return ConstantFP::get(CI->getType(), 1.0);
-
-    if (Op2C->isExactlyValue(0.5) &&
-        hasUnaryFloatFn(TLI, Op2->getType(), LibFunc::sqrt, LibFunc::sqrtf,
-                        LibFunc::sqrtl) &&
-        hasUnaryFloatFn(TLI, Op2->getType(), LibFunc::fabs, LibFunc::fabsf,
-                        LibFunc::fabsl)) {
-      // Expand pow(x, 0.5) to (x == -infinity ? +infinity : fabs(sqrt(x))).
-      // This is faster than calling pow, and still handles negative zero
-      // and negative infinity correctly.
-      // TODO: In fast-math mode, this could be just sqrt(x).
-      // TODO: In finite-only mode, this could be just fabs(sqrt(x)).
-      Value *Inf = ConstantFP::getInfinity(CI->getType());
-      Value *NegInf = ConstantFP::getInfinity(CI->getType(), true);
-      Value *Sqrt = EmitUnaryFloatFnCall(Op1, "sqrt", B,
-                                         Callee->getAttributes());
-      Value *FAbs = EmitUnaryFloatFnCall(Sqrt, "fabs", B,
-                                         Callee->getAttributes());
-      Value *FCmp = B.CreateFCmpOEQ(Op1, NegInf);
-      Value *Sel = B.CreateSelect(FCmp, Inf, FAbs);
-      return Sel;
-    }
+    if (LdExpArg) {
+      Constant *One = ConstantFP::get(CI->getContext(), APFloat(1.0f));
+      if (!Op->getType()->isFloatTy())
+        One = ConstantExpr::getFPExtend(One, Op->getType());
+
+      Module *M = Caller->getParent();
+      Value *Callee =
+          M->getOrInsertFunction(TLI->getName(LdExp), Op->getType(),
+                                 Op->getType(), B.getInt32Ty(), nullptr);
+      CallInst *CI = B.CreateCall2(Callee, One, LdExpArg);
+      if (const Function *F = dyn_cast<Function>(Callee->stripPointerCasts()))
+        CI->setCallingConv(F->getCallingConv());
 
-    if (Op2C->isExactlyValue(1.0))  // pow(x, 1.0) -> x
-      return Op1;
-    if (Op2C->isExactlyValue(2.0))  // pow(x, 2.0) -> x*x
-      return B.CreateFMul(Op1, Op1, "pow2");
-    if (Op2C->isExactlyValue(-1.0)) // pow(x, -1.0) -> 1.0/x
-      return B.CreateFDiv(ConstantFP::get(CI->getType(), 1.0),
-                          Op1, "powrecip");
-    return nullptr;
-  }
-};
-
-struct Exp2Opt : public UnsafeFPLibCallOptimization {
-  Exp2Opt(bool UnsafeFPShrink) : UnsafeFPLibCallOptimization(UnsafeFPShrink) {}
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    Value *Ret = nullptr;
-    if (UnsafeFPShrink && Callee->getName() == "exp2" &&
-        TLI->has(LibFunc::exp2f)) {
-      UnaryDoubleFPOpt UnsafeUnaryDoubleFP(true);
-      Ret = UnsafeUnaryDoubleFP.callOptimizer(Callee, CI, B);
+      return CI;
     }
+  }
+  return Ret;
+}
 
-    FunctionType *FT = Callee->getFunctionType();
-    // Just make sure this has 1 argument of FP type, which matches the
-    // result type.
-    if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
-        !FT->getParamType(0)->isFloatingPointTy())
-      return Ret;
+Value *LibCallSimplifier::optimizeFabs(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
 
-    Value *Op = CI->getArgOperand(0);
-    // Turn exp2(sitofp(x)) -> ldexp(1.0, sext(x))  if sizeof(x) <= 32
-    // Turn exp2(uitofp(x)) -> ldexp(1.0, zext(x))  if sizeof(x) < 32
-    LibFunc::Func LdExp = LibFunc::ldexpl;
-    if (Op->getType()->isFloatTy())
-      LdExp = LibFunc::ldexpf;
-    else if (Op->getType()->isDoubleTy())
-      LdExp = LibFunc::ldexp;
-
-    if (TLI->has(LdExp)) {
-      Value *LdExpArg = nullptr;
-      if (SIToFPInst *OpC = dyn_cast<SIToFPInst>(Op)) {
-        if (OpC->getOperand(0)->getType()->getPrimitiveSizeInBits() <= 32)
-          LdExpArg = B.CreateSExt(OpC->getOperand(0), B.getInt32Ty());
-      } else if (UIToFPInst *OpC = dyn_cast<UIToFPInst>(Op)) {
-        if (OpC->getOperand(0)->getType()->getPrimitiveSizeInBits() < 32)
-          LdExpArg = B.CreateZExt(OpC->getOperand(0), B.getInt32Ty());
-      }
+  Value *Ret = nullptr;
+  if (Callee->getName() == "fabs" && TLI->has(LibFunc::fabsf)) {
+    Ret = optimizeUnaryDoubleFP(CI, B, false);
+  }
 
-      if (LdExpArg) {
-        Constant *One = ConstantFP::get(*Context, APFloat(1.0f));
-        if (!Op->getType()->isFloatTy())
-          One = ConstantExpr::getFPExtend(One, Op->getType());
+  FunctionType *FT = Callee->getFunctionType();
+  // Make sure this has 1 argument of FP type which matches the result type.
+  if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
+      !FT->getParamType(0)->isFloatingPointTy())
+    return Ret;
 
-        Module *M = Caller->getParent();
-        Value *Callee =
-            M->getOrInsertFunction(TLI->getName(LdExp), Op->getType(),
-                                   Op->getType(), B.getInt32Ty(), NULL);
-        CallInst *CI = B.CreateCall2(Callee, One, LdExpArg);
-        if (const Function *F = dyn_cast<Function>(Callee->stripPointerCasts()))
-          CI->setCallingConv(F->getCallingConv());
+  Value *Op = CI->getArgOperand(0);
+  if (Instruction *I = dyn_cast<Instruction>(Op)) {
+    // Fold fabs(x * x) -> x * x; any squared FP value must already be positive.
+    if (I->getOpcode() == Instruction::FMul)
+      if (I->getOperand(0) == I->getOperand(1))
+        return Op;
+  }
+  return Ret;
+}
 
-        return CI;
+Value *LibCallSimplifier::optimizeSqrt(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  
+  Value *Ret = nullptr;
+  if (TLI->has(LibFunc::sqrtf) && (Callee->getName() == "sqrt" ||
+                                   Callee->getIntrinsicID() == Intrinsic::sqrt))
+    Ret = optimizeUnaryDoubleFP(CI, B, true);
+
+  // FIXME: For finer-grain optimization, we need intrinsics to have the same
+  // fast-math flag decorations that are applied to FP instructions. For now,
+  // we have to rely on the function-level unsafe-fp-math attribute to do this
+  // optimization because there's no other way to express that the sqrt can be
+  // reassociated.
+  Function *F = CI->getParent()->getParent();
+  if (F->hasFnAttribute("unsafe-fp-math")) {
+    // Check for unsafe-fp-math = true.
+    Attribute Attr = F->getFnAttribute("unsafe-fp-math");
+    if (Attr.getValueAsString() != "true")
+      return Ret;
+  }
+  Value *Op = CI->getArgOperand(0);
+  if (Instruction *I = dyn_cast<Instruction>(Op)) {
+    if (I->getOpcode() == Instruction::FMul && I->hasUnsafeAlgebra()) {
+      // We're looking for a repeated factor in a multiplication tree,
+      // so we can do this fold: sqrt(x * x) -> fabs(x);
+      // or this fold: sqrt(x * x * y) -> fabs(x) * sqrt(y).
+      Value *Op0 = I->getOperand(0);
+      Value *Op1 = I->getOperand(1);
+      Value *RepeatOp = nullptr;
+      Value *OtherOp = nullptr;
+      if (Op0 == Op1) {
+        // Simple match: the operands of the multiply are identical.
+        RepeatOp = Op0;
+      } else {
+        // Look for a more complicated pattern: one of the operands is itself
+        // a multiply, so search for a common factor in that multiply.
+        // Note: We don't bother looking any deeper than this first level or for
+        // variations of this pattern because instcombine's visitFMUL and/or the
+        // reassociation pass should give us this form.
+        Value *OtherMul0, *OtherMul1;
+        if (match(Op0, m_FMul(m_Value(OtherMul0), m_Value(OtherMul1)))) {
+          // Pattern: sqrt((x * y) * z)
+          if (OtherMul0 == OtherMul1) {
+            // Matched: sqrt((x * x) * z)
+            RepeatOp = OtherMul0;
+            OtherOp = Op1;
+          }
+        }
+      }
+      if (RepeatOp) {
+        // Fast math flags for any created instructions should match the sqrt
+        // and multiply.
+        // FIXME: We're not checking the sqrt because it doesn't have
+        // fast-math-flags (see earlier comment).
+        IRBuilder<true, ConstantFolder,
+          IRBuilderDefaultInserter<true> >::FastMathFlagGuard Guard(B);
+        B.SetFastMathFlags(I->getFastMathFlags());
+        // If we found a repeated factor, hoist it out of the square root and
+        // replace it with the fabs of that factor.
+        Module *M = Callee->getParent();
+        Type *ArgType = Op->getType();
+        Value *Fabs = Intrinsic::getDeclaration(M, Intrinsic::fabs, ArgType);
+        Value *FabsCall = B.CreateCall(Fabs, RepeatOp, "fabs");
+        if (OtherOp) {
+          // If we found a non-repeated factor, we still need to get its square
+          // root. We then multiply that by the value that was simplified out
+          // of the square root calculation.
+          Value *Sqrt = Intrinsic::getDeclaration(M, Intrinsic::sqrt, ArgType);
+          Value *SqrtCall = B.CreateCall(Sqrt, OtherOp, "sqrt");
+          return B.CreateFMul(FabsCall, SqrtCall);
+        }
+        return FabsCall;
       }
     }
-    return Ret;
   }
-};
+  return Ret;
+}
 
-struct SinCosPiOpt : public LibCallOptimization {
-  SinCosPiOpt() {}
+static bool isTrigLibCall(CallInst *CI);
+static void insertSinCosCall(IRBuilder<> &B, Function *OrigCallee, Value *Arg,
+                             bool UseFloat, Value *&Sin, Value *&Cos,
+                             Value *&SinCos);
 
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    // Make sure the prototype is as expected, otherwise the rest of the
-    // function is probably invalid and likely to abort.
-    if (!isTrigLibCall(CI))
-      return nullptr;
+Value *LibCallSimplifier::optimizeSinCosPi(CallInst *CI, IRBuilder<> &B) {
 
-    Value *Arg = CI->getArgOperand(0);
-    SmallVector<CallInst *, 1> SinCalls;
-    SmallVector<CallInst *, 1> CosCalls;
-    SmallVector<CallInst *, 1> SinCosCalls;
+  // Make sure the prototype is as expected, otherwise the rest of the
+  // function is probably invalid and likely to abort.
+  if (!isTrigLibCall(CI))
+    return nullptr;
 
-    bool IsFloat = Arg->getType()->isFloatTy();
+  Value *Arg = CI->getArgOperand(0);
+  SmallVector<CallInst *, 1> SinCalls;
+  SmallVector<CallInst *, 1> CosCalls;
+  SmallVector<CallInst *, 1> SinCosCalls;
 
-    // Look for all compatible sinpi, cospi and sincospi calls with the same
-    // argument. If there are enough (in some sense) we can make the
-    // substitution.
-    for (User *U : Arg->users())
-      classifyArgUse(U, CI->getParent(), IsFloat, SinCalls, CosCalls,
-                     SinCosCalls);
+  bool IsFloat = Arg->getType()->isFloatTy();
 
-    // It's only worthwhile if both sinpi and cospi are actually used.
-    if (SinCosCalls.empty() && (SinCalls.empty() || CosCalls.empty()))
-      return nullptr;
+  // Look for all compatible sinpi, cospi and sincospi calls with the same
+  // argument. If there are enough (in some sense) we can make the
+  // substitution.
+  for (User *U : Arg->users())
+    classifyArgUse(U, CI->getParent(), IsFloat, SinCalls, CosCalls,
+                   SinCosCalls);
 
-    Value *Sin, *Cos, *SinCos;
-    insertSinCosCall(B, CI->getCalledFunction(), Arg, IsFloat, Sin, Cos,
-                     SinCos);
-
-    replaceTrigInsts(SinCalls, Sin);
-    replaceTrigInsts(CosCalls, Cos);
-    replaceTrigInsts(SinCosCalls, SinCos);
-
-    return nullptr;
-  }
-
-  bool isTrigLibCall(CallInst *CI) {
-    Function *Callee = CI->getCalledFunction();
-    FunctionType *FT = Callee->getFunctionType();
-
-    // We can only hope to do anything useful if we can ignore things like errno
-    // and floating-point exceptions.
-    bool AttributesSafe = CI->hasFnAttr(Attribute::NoUnwind) &&
-                          CI->hasFnAttr(Attribute::ReadNone);
-
-    // Other than that we need float(float) or double(double)
-    return AttributesSafe && FT->getNumParams() == 1 &&
-           FT->getReturnType() == FT->getParamType(0) &&
-           (FT->getParamType(0)->isFloatTy() ||
-            FT->getParamType(0)->isDoubleTy());
-  }
-
-  void classifyArgUse(Value *Val, BasicBlock *BB, bool IsFloat,
-                      SmallVectorImpl<CallInst *> &SinCalls,
-                      SmallVectorImpl<CallInst *> &CosCalls,
-                      SmallVectorImpl<CallInst *> &SinCosCalls) {
-    CallInst *CI = dyn_cast<CallInst>(Val);
-
-    if (!CI)
-      return;
-
-    Function *Callee = CI->getCalledFunction();
-    StringRef FuncName = Callee->getName();
-    LibFunc::Func Func;
-    if (!TLI->getLibFunc(FuncName, Func) || !TLI->has(Func) ||
-        !isTrigLibCall(CI))
-      return;
-
-    if (IsFloat) {
-      if (Func == LibFunc::sinpif)
-        SinCalls.push_back(CI);
-      else if (Func == LibFunc::cospif)
-        CosCalls.push_back(CI);
-      else if (Func == LibFunc::sincospif_stret)
-        SinCosCalls.push_back(CI);
-    } else {
-      if (Func == LibFunc::sinpi)
-        SinCalls.push_back(CI);
-      else if (Func == LibFunc::cospi)
-        CosCalls.push_back(CI);
-      else if (Func == LibFunc::sincospi_stret)
-        SinCosCalls.push_back(CI);
-    }
-  }
+  // It's only worthwhile if both sinpi and cospi are actually used.
+  if (SinCosCalls.empty() && (SinCalls.empty() || CosCalls.empty()))
+    return nullptr;
 
-  void replaceTrigInsts(SmallVectorImpl<CallInst*> &Calls, Value *Res) {
-    for (SmallVectorImpl<CallInst*>::iterator I = Calls.begin(),
-           E = Calls.end();
-         I != E; ++I) {
-      LCS->replaceAllUsesWith(*I, Res);
-    }
-  }
+  Value *Sin, *Cos, *SinCos;
+  insertSinCosCall(B, CI->getCalledFunction(), Arg, IsFloat, Sin, Cos, SinCos);
 
-  void insertSinCosCall(IRBuilder<> &B, Function *OrigCallee, Value *Arg,
-                        bool UseFloat, Value *&Sin, Value *&Cos,
-                        Value *&SinCos) {
-    Type *ArgTy = Arg->getType();
-    Type *ResTy;
-    StringRef Name;
-
-    Triple T(OrigCallee->getParent()->getTargetTriple());
-    if (UseFloat) {
-      Name = "__sincospif_stret";
-
-      assert(T.getArch() != Triple::x86 && "x86 messy and unsupported for now");
-      // x86_64 can't use {float, float} since that would be returned in both
-      // xmm0 and xmm1, which isn't what a real struct would do.
-      ResTy = T.getArch() == Triple::x86_64
-                  ? static_cast<Type *>(VectorType::get(ArgTy, 2))
-                  : static_cast<Type *>(StructType::get(ArgTy, ArgTy, NULL));
-    } else {
-      Name = "__sincospi_stret";
-      ResTy = StructType::get(ArgTy, ArgTy, NULL);
-    }
+  replaceTrigInsts(SinCalls, Sin);
+  replaceTrigInsts(CosCalls, Cos);
+  replaceTrigInsts(SinCosCalls, SinCos);
 
-    Module *M = OrigCallee->getParent();
-    Value *Callee = M->getOrInsertFunction(Name, OrigCallee->getAttributes(),
-                                           ResTy, ArgTy, NULL);
-
-    if (Instruction *ArgInst = dyn_cast<Instruction>(Arg)) {
-      // If the argument is an instruction, it must dominate all uses so put our
-      // sincos call there.
-      BasicBlock::iterator Loc = ArgInst;
-      B.SetInsertPoint(ArgInst->getParent(), ++Loc);
-    } else {
-      // Otherwise (e.g. for a constant) the beginning of the function is as
-      // good a place as any.
-      BasicBlock &EntryBB = B.GetInsertBlock()->getParent()->getEntryBlock();
-      B.SetInsertPoint(&EntryBB, EntryBB.begin());
-    }
+  return nullptr;
+}
 
-    SinCos = B.CreateCall(Callee, Arg, "sincospi");
+static bool isTrigLibCall(CallInst *CI) {
+  Function *Callee = CI->getCalledFunction();
+  FunctionType *FT = Callee->getFunctionType();
+
+  // We can only hope to do anything useful if we can ignore things like errno
+  // and floating-point exceptions.
+  bool AttributesSafe =
+      CI->hasFnAttr(Attribute::NoUnwind) && CI->hasFnAttr(Attribute::ReadNone);
+
+  // Other than that we need float(float) or double(double)
+  return AttributesSafe && FT->getNumParams() == 1 &&
+         FT->getReturnType() == FT->getParamType(0) &&
+         (FT->getParamType(0)->isFloatTy() ||
+          FT->getParamType(0)->isDoubleTy());
+}
 
-    if (SinCos->getType()->isStructTy()) {
-      Sin = B.CreateExtractValue(SinCos, 0, "sinpi");
-      Cos = B.CreateExtractValue(SinCos, 1, "cospi");
-    } else {
-      Sin = B.CreateExtractElement(SinCos, ConstantInt::get(B.getInt32Ty(), 0),
-                                   "sinpi");
-      Cos = B.CreateExtractElement(SinCos, ConstantInt::get(B.getInt32Ty(), 1),
-                                   "cospi");
-    }
+void
+LibCallSimplifier::classifyArgUse(Value *Val, BasicBlock *BB, bool IsFloat,
+                                  SmallVectorImpl<CallInst *> &SinCalls,
+                                  SmallVectorImpl<CallInst *> &CosCalls,
+                                  SmallVectorImpl<CallInst *> &SinCosCalls) {
+  CallInst *CI = dyn_cast<CallInst>(Val);
+
+  if (!CI)
+    return;
+
+  Function *Callee = CI->getCalledFunction();
+  StringRef FuncName = Callee->getName();
+  LibFunc::Func Func;
+  if (!TLI->getLibFunc(FuncName, Func) || !TLI->has(Func) || !isTrigLibCall(CI))
+    return;
+
+  if (IsFloat) {
+    if (Func == LibFunc::sinpif)
+      SinCalls.push_back(CI);
+    else if (Func == LibFunc::cospif)
+      CosCalls.push_back(CI);
+    else if (Func == LibFunc::sincospif_stret)
+      SinCosCalls.push_back(CI);
+  } else {
+    if (Func == LibFunc::sinpi)
+      SinCalls.push_back(CI);
+    else if (Func == LibFunc::cospi)
+      CosCalls.push_back(CI);
+    else if (Func == LibFunc::sincospi_stret)
+      SinCosCalls.push_back(CI);
+  }
+}
+
+void LibCallSimplifier::replaceTrigInsts(SmallVectorImpl<CallInst *> &Calls,
+                                         Value *Res) {
+  for (SmallVectorImpl<CallInst *>::iterator I = Calls.begin(), E = Calls.end();
+       I != E; ++I) {
+    replaceAllUsesWith(*I, Res);
   }
+}
 
-};
+void insertSinCosCall(IRBuilder<> &B, Function *OrigCallee, Value *Arg,
+                      bool UseFloat, Value *&Sin, Value *&Cos, Value *&SinCos) {
+  Type *ArgTy = Arg->getType();
+  Type *ResTy;
+  StringRef Name;
+
+  Triple T(OrigCallee->getParent()->getTargetTriple());
+  if (UseFloat) {
+    Name = "__sincospif_stret";
+
+    assert(T.getArch() != Triple::x86 && "x86 messy and unsupported for now");
+    // x86_64 can't use {float, float} since that would be returned in both
+    // xmm0 and xmm1, which isn't what a real struct would do.
+    ResTy = T.getArch() == Triple::x86_64
+                ? static_cast<Type *>(VectorType::get(ArgTy, 2))
+                : static_cast<Type *>(StructType::get(ArgTy, ArgTy, nullptr));
+  } else {
+    Name = "__sincospi_stret";
+    ResTy = StructType::get(ArgTy, ArgTy, nullptr);
+  }
+
+  Module *M = OrigCallee->getParent();
+  Value *Callee = M->getOrInsertFunction(Name, OrigCallee->getAttributes(),
+                                         ResTy, ArgTy, nullptr);
+
+  if (Instruction *ArgInst = dyn_cast<Instruction>(Arg)) {
+    // If the argument is an instruction, it must dominate all uses so put our
+    // sincos call there.
+    BasicBlock::iterator Loc = ArgInst;
+    B.SetInsertPoint(ArgInst->getParent(), ++Loc);
+  } else {
+    // Otherwise (e.g. for a constant) the beginning of the function is as
+    // good a place as any.
+    BasicBlock &EntryBB = B.GetInsertBlock()->getParent()->getEntryBlock();
+    B.SetInsertPoint(&EntryBB, EntryBB.begin());
+  }
+
+  SinCos = B.CreateCall(Callee, Arg, "sincospi");
+
+  if (SinCos->getType()->isStructTy()) {
+    Sin = B.CreateExtractValue(SinCos, 0, "sinpi");
+    Cos = B.CreateExtractValue(SinCos, 1, "cospi");
+  } else {
+    Sin = B.CreateExtractElement(SinCos, ConstantInt::get(B.getInt32Ty(), 0),
+                                 "sinpi");
+    Cos = B.CreateExtractElement(SinCos, ConstantInt::get(B.getInt32Ty(), 1),
+                                 "cospi");
+  }
+}
 
 //===----------------------------------------------------------------------===//
 // Integer Library Call Optimizations
 //===----------------------------------------------------------------------===//
 
-struct FFSOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    FunctionType *FT = Callee->getFunctionType();
-    // Just make sure this has 2 arguments of the same FP type, which match the
-    // result type.
-    if (FT->getNumParams() != 1 ||
-        !FT->getReturnType()->isIntegerTy(32) ||
-        !FT->getParamType(0)->isIntegerTy())
-      return nullptr;
+Value *LibCallSimplifier::optimizeFFS(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  FunctionType *FT = Callee->getFunctionType();
+  // Just make sure this has 2 arguments of the same FP type, which match the
+  // result type.
+  if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy(32) ||
+      !FT->getParamType(0)->isIntegerTy())
+    return nullptr;
 
-    Value *Op = CI->getArgOperand(0);
+  Value *Op = CI->getArgOperand(0);
 
-    // Constant fold.
-    if (ConstantInt *CI = dyn_cast<ConstantInt>(Op)) {
-      if (CI->isZero()) // ffs(0) -> 0.
-        return B.getInt32(0);
-      // ffs(c) -> cttz(c)+1
-      return B.getInt32(CI->getValue().countTrailingZeros() + 1);
-    }
+  // Constant fold.
+  if (ConstantInt *CI = dyn_cast<ConstantInt>(Op)) {
+    if (CI->isZero()) // ffs(0) -> 0.
+      return B.getInt32(0);
+    // ffs(c) -> cttz(c)+1
+    return B.getInt32(CI->getValue().countTrailingZeros() + 1);
+  }
 
-    // ffs(x) -> x != 0 ? (i32)llvm.cttz(x)+1 : 0
-    Type *ArgType = Op->getType();
-    Value *F = Intrinsic::getDeclaration(Callee->getParent(),
-                                         Intrinsic::cttz, ArgType);
-    Value *V = B.CreateCall2(F, Op, B.getFalse(), "cttz");
-    V = B.CreateAdd(V, ConstantInt::get(V->getType(), 1));
-    V = B.CreateIntCast(V, B.getInt32Ty(), false);
-
-    Value *Cond = B.CreateICmpNE(Op, Constant::getNullValue(ArgType));
-    return B.CreateSelect(Cond, V, B.getInt32(0));
-  }
-};
-
-struct AbsOpt : public LibCallOptimization {
-  bool ignoreCallingConv() override { return true; }
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    FunctionType *FT = Callee->getFunctionType();
-    // We require integer(integer) where the types agree.
-    if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() ||
-        FT->getParamType(0) != FT->getReturnType())
-      return nullptr;
+  // ffs(x) -> x != 0 ? (i32)llvm.cttz(x)+1 : 0
+  Type *ArgType = Op->getType();
+  Value *F =
+      Intrinsic::getDeclaration(Callee->getParent(), Intrinsic::cttz, ArgType);
+  Value *V = B.CreateCall2(F, Op, B.getFalse(), "cttz");
+  V = B.CreateAdd(V, ConstantInt::get(V->getType(), 1));
+  V = B.CreateIntCast(V, B.getInt32Ty(), false);
 
-    // abs(x) -> x >s -1 ? x : -x
-    Value *Op = CI->getArgOperand(0);
-    Value *Pos = B.CreateICmpSGT(Op, Constant::getAllOnesValue(Op->getType()),
-                                 "ispos");
-    Value *Neg = B.CreateNeg(Op, "neg");
-    return B.CreateSelect(Pos, Op, Neg);
-  }
-};
-
-struct IsDigitOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    FunctionType *FT = Callee->getFunctionType();
-    // We require integer(i32)
-    if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() ||
-        !FT->getParamType(0)->isIntegerTy(32))
-      return nullptr;
+  Value *Cond = B.CreateICmpNE(Op, Constant::getNullValue(ArgType));
+  return B.CreateSelect(Cond, V, B.getInt32(0));
+}
 
-    // isdigit(c) -> (c-'0') <u 10
-    Value *Op = CI->getArgOperand(0);
-    Op = B.CreateSub(Op, B.getInt32('0'), "isdigittmp");
-    Op = B.CreateICmpULT(Op, B.getInt32(10), "isdigit");
-    return B.CreateZExt(Op, CI->getType());
-  }
-};
-
-struct IsAsciiOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    FunctionType *FT = Callee->getFunctionType();
-    // We require integer(i32)
-    if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() ||
-        !FT->getParamType(0)->isIntegerTy(32))
-      return nullptr;
+Value *LibCallSimplifier::optimizeAbs(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  FunctionType *FT = Callee->getFunctionType();
+  // We require integer(integer) where the types agree.
+  if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() ||
+      FT->getParamType(0) != FT->getReturnType())
+    return nullptr;
 
-    // isascii(c) -> c <u 128
-    Value *Op = CI->getArgOperand(0);
-    Op = B.CreateICmpULT(Op, B.getInt32(128), "isascii");
-    return B.CreateZExt(Op, CI->getType());
-  }
-};
+  // abs(x) -> x >s -1 ? x : -x
+  Value *Op = CI->getArgOperand(0);
+  Value *Pos =
+      B.CreateICmpSGT(Op, Constant::getAllOnesValue(Op->getType()), "ispos");
+  Value *Neg = B.CreateNeg(Op, "neg");
+  return B.CreateSelect(Pos, Op, Neg);
+}
 
-struct ToAsciiOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    FunctionType *FT = Callee->getFunctionType();
-    // We require i32(i32)
-    if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
-        !FT->getParamType(0)->isIntegerTy(32))
-      return nullptr;
+Value *LibCallSimplifier::optimizeIsDigit(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  FunctionType *FT = Callee->getFunctionType();
+  // We require integer(i32)
+  if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() ||
+      !FT->getParamType(0)->isIntegerTy(32))
+    return nullptr;
 
-    // toascii(c) -> c & 0x7f
-    return B.CreateAnd(CI->getArgOperand(0),
-                       ConstantInt::get(CI->getType(),0x7F));
-  }
-};
+  // isdigit(c) -> (c-'0') <u 10
+  Value *Op = CI->getArgOperand(0);
+  Op = B.CreateSub(Op, B.getInt32('0'), "isdigittmp");
+  Op = B.CreateICmpULT(Op, B.getInt32(10), "isdigit");
+  return B.CreateZExt(Op, CI->getType());
+}
+
+Value *LibCallSimplifier::optimizeIsAscii(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  FunctionType *FT = Callee->getFunctionType();
+  // We require integer(i32)
+  if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() ||
+      !FT->getParamType(0)->isIntegerTy(32))
+    return nullptr;
+
+  // isascii(c) -> c <u 128
+  Value *Op = CI->getArgOperand(0);
+  Op = B.CreateICmpULT(Op, B.getInt32(128), "isascii");
+  return B.CreateZExt(Op, CI->getType());
+}
+
+Value *LibCallSimplifier::optimizeToAscii(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  FunctionType *FT = Callee->getFunctionType();
+  // We require i32(i32)
+  if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
+      !FT->getParamType(0)->isIntegerTy(32))
+    return nullptr;
+
+  // toascii(c) -> c & 0x7f
+  return B.CreateAnd(CI->getArgOperand(0),
+                     ConstantInt::get(CI->getType(), 0x7F));
+}
 
 //===----------------------------------------------------------------------===//
 // Formatting and IO Library Call Optimizations
 //===----------------------------------------------------------------------===//
 
-struct ErrorReportingOpt : public LibCallOptimization {
-  ErrorReportingOpt(int S = -1) : StreamArg(S) {}
+static bool isReportingError(Function *Callee, CallInst *CI, int StreamArg);
 
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &) override {
-    // Error reporting calls should be cold, mark them as such.
-    // This applies even to non-builtin calls: it is only a hint and applies to
-    // functions that the frontend might not understand as builtins.
+Value *LibCallSimplifier::optimizeErrorReporting(CallInst *CI, IRBuilder<> &B,
+                                                 int StreamArg) {
+  // Error reporting calls should be cold, mark them as such.
+  // This applies even to non-builtin calls: it is only a hint and applies to
+  // functions that the frontend might not understand as builtins.
 
-    // This heuristic was suggested in:
-    // Improving Static Branch Prediction in a Compiler
-    // Brian L. Deitrich, Ben-Chung Cheng, Wen-mei W. Hwu
-    // Proceedings of PACT'98, Oct. 1998, IEEE
-
-    if (!CI->hasFnAttr(Attribute::Cold) && isReportingError(Callee, CI)) {
-      CI->addAttribute(AttributeSet::FunctionIndex, Attribute::Cold);
-    }
+  // This heuristic was suggested in:
+  // Improving Static Branch Prediction in a Compiler
+  // Brian L. Deitrich, Ben-Chung Cheng, Wen-mei W. Hwu
+  // Proceedings of PACT'98, Oct. 1998, IEEE
+  Function *Callee = CI->getCalledFunction();
 
-    return nullptr;
+  if (!CI->hasFnAttr(Attribute::Cold) &&
+      isReportingError(Callee, CI, StreamArg)) {
+    CI->addAttribute(AttributeSet::FunctionIndex, Attribute::Cold);
   }
 
-protected:
-  bool isReportingError(Function *Callee, CallInst *CI) {
-    if (!ColdErrorCalls)
-      return false;
- 
-    if (!Callee || !Callee->isDeclaration())
-      return false;
+  return nullptr;
+}
 
-    if (StreamArg < 0)
-      return true;
+static bool isReportingError(Function *Callee, CallInst *CI, int StreamArg) {
+  if (!ColdErrorCalls)
+    return false;
 
-    // These functions might be considered cold, but only if their stream
-    // argument is stderr.
+  if (!Callee || !Callee->isDeclaration())
+    return false;
 
-    if (StreamArg >= (int) CI->getNumArgOperands())
-      return false;
-    LoadInst *LI = dyn_cast<LoadInst>(CI->getArgOperand(StreamArg));
-    if (!LI)
-      return false;
-    GlobalVariable *GV = dyn_cast<GlobalVariable>(LI->getPointerOperand());
-    if (!GV || !GV->isDeclaration())
-      return false;
-    return GV->getName() == "stderr";
-  }
+  if (StreamArg < 0)
+    return true;
 
-  int StreamArg;
-};
+  // These functions might be considered cold, but only if their stream
+  // argument is stderr.
 
-struct PrintFOpt : public LibCallOptimization {
-  Value *optimizeFixedFormatString(Function *Callee, CallInst *CI,
-                                   IRBuilder<> &B) {
-    // Check for a fixed format string.
-    StringRef FormatStr;
-    if (!getConstantStringInfo(CI->getArgOperand(0), FormatStr))
-      return nullptr;
+  if (StreamArg >= (int)CI->getNumArgOperands())
+    return false;
+  LoadInst *LI = dyn_cast<LoadInst>(CI->getArgOperand(StreamArg));
+  if (!LI)
+    return false;
+  GlobalVariable *GV = dyn_cast<GlobalVariable>(LI->getPointerOperand());
+  if (!GV || !GV->isDeclaration())
+    return false;
+  return GV->getName() == "stderr";
+}
 
-    // Empty format string -> noop.
-    if (FormatStr.empty())  // Tolerate printf's declared void.
-      return CI->use_empty() ? (Value*)CI :
-                               ConstantInt::get(CI->getType(), 0);
+Value *LibCallSimplifier::optimizePrintFString(CallInst *CI, IRBuilder<> &B) {
+  // Check for a fixed format string.
+  StringRef FormatStr;
+  if (!getConstantStringInfo(CI->getArgOperand(0), FormatStr))
+    return nullptr;
 
-    // Do not do any of the following transformations if the printf return value
-    // is used, in general the printf return value is not compatible with either
-    // putchar() or puts().
-    if (!CI->use_empty())
-      return nullptr;
+  // Empty format string -> noop.
+  if (FormatStr.empty()) // Tolerate printf's declared void.
+    return CI->use_empty() ? (Value *)CI : ConstantInt::get(CI->getType(), 0);
 
-    // printf("x") -> putchar('x'), even for '%'.
-    if (FormatStr.size() == 1) {
-      Value *Res = EmitPutChar(B.getInt32(FormatStr[0]), B, DL, TLI);
-      if (CI->use_empty() || !Res) return Res;
-      return B.CreateIntCast(Res, CI->getType(), true);
-    }
+  // Do not do any of the following transformations if the printf return value
+  // is used, in general the printf return value is not compatible with either
+  // putchar() or puts().
+  if (!CI->use_empty())
+    return nullptr;
 
-    // printf("foo\n") --> puts("foo")
-    if (FormatStr[FormatStr.size()-1] == '\n' &&
-        FormatStr.find('%') == StringRef::npos) { // No format characters.
-      // Create a string literal with no \n on it.  We expect the constant merge
-      // pass to be run after this pass, to merge duplicate strings.
-      FormatStr = FormatStr.drop_back();
-      Value *GV = B.CreateGlobalString(FormatStr, "str");
-      Value *NewCI = EmitPutS(GV, B, DL, TLI);
-      return (CI->use_empty() || !NewCI) ?
-              NewCI :
-              ConstantInt::get(CI->getType(), FormatStr.size()+1);
-    }
+  // printf("x") -> putchar('x'), even for '%'.
+  if (FormatStr.size() == 1) {
+    Value *Res = EmitPutChar(B.getInt32(FormatStr[0]), B, DL, TLI);
+    if (CI->use_empty() || !Res)
+      return Res;
+    return B.CreateIntCast(Res, CI->getType(), true);
+  }
 
-    // Optimize specific format strings.
-    // printf("%c", chr) --> putchar(chr)
-    if (FormatStr == "%c" && CI->getNumArgOperands() > 1 &&
-        CI->getArgOperand(1)->getType()->isIntegerTy()) {
-      Value *Res = EmitPutChar(CI->getArgOperand(1), B, DL, TLI);
+  // printf("foo\n") --> puts("foo")
+  if (FormatStr[FormatStr.size() - 1] == '\n' &&
+      FormatStr.find('%') == StringRef::npos) { // No format characters.
+    // Create a string literal with no \n on it.  We expect the constant merge
+    // pass to be run after this pass, to merge duplicate strings.
+    FormatStr = FormatStr.drop_back();
+    Value *GV = B.CreateGlobalString(FormatStr, "str");
+    Value *NewCI = EmitPutS(GV, B, DL, TLI);
+    return (CI->use_empty() || !NewCI)
+               ? NewCI
+               : ConstantInt::get(CI->getType(), FormatStr.size() + 1);
+  }
 
-      if (CI->use_empty() || !Res) return Res;
-      return B.CreateIntCast(Res, CI->getType(), true);
-    }
+  // Optimize specific format strings.
+  // printf("%c", chr) --> putchar(chr)
+  if (FormatStr == "%c" && CI->getNumArgOperands() > 1 &&
+      CI->getArgOperand(1)->getType()->isIntegerTy()) {
+    Value *Res = EmitPutChar(CI->getArgOperand(1), B, DL, TLI);
 
-    // printf("%s\n", str) --> puts(str)
-    if (FormatStr == "%s\n" && CI->getNumArgOperands() > 1 &&
-        CI->getArgOperand(1)->getType()->isPointerTy()) {
-      return EmitPutS(CI->getArgOperand(1), B, DL, TLI);
-    }
-    return nullptr;
+    if (CI->use_empty() || !Res)
+      return Res;
+    return B.CreateIntCast(Res, CI->getType(), true);
   }
 
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    // Require one fixed pointer argument and an integer/void result.
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() < 1 || !FT->getParamType(0)->isPointerTy() ||
-        !(FT->getReturnType()->isIntegerTy() ||
-          FT->getReturnType()->isVoidTy()))
-      return nullptr;
+  // printf("%s\n", str) --> puts(str)
+  if (FormatStr == "%s\n" && CI->getNumArgOperands() > 1 &&
+      CI->getArgOperand(1)->getType()->isPointerTy()) {
+    return EmitPutS(CI->getArgOperand(1), B, DL, TLI);
+  }
+  return nullptr;
+}
 
-    if (Value *V = optimizeFixedFormatString(Callee, CI, B)) {
-      return V;
-    }
+Value *LibCallSimplifier::optimizePrintF(CallInst *CI, IRBuilder<> &B) {
 
-    // printf(format, ...) -> iprintf(format, ...) if no floating point
-    // arguments.
-    if (TLI->has(LibFunc::iprintf) && !callHasFloatingPointArgument(CI)) {
-      Module *M = B.GetInsertBlock()->getParent()->getParent();
-      Constant *IPrintFFn =
-        M->getOrInsertFunction("iprintf", FT, Callee->getAttributes());
-      CallInst *New = cast<CallInst>(CI->clone());
-      New->setCalledFunction(IPrintFFn);
-      B.Insert(New);
-      return New;
-    }
+  Function *Callee = CI->getCalledFunction();
+  // Require one fixed pointer argument and an integer/void result.
+  FunctionType *FT = Callee->getFunctionType();
+  if (FT->getNumParams() < 1 || !FT->getParamType(0)->isPointerTy() ||
+      !(FT->getReturnType()->isIntegerTy() || FT->getReturnType()->isVoidTy()))
     return nullptr;
+
+  if (Value *V = optimizePrintFString(CI, B)) {
+    return V;
   }
-};
 
-struct SPrintFOpt : public LibCallOptimization {
-  Value *OptimizeFixedFormatString(Function *Callee, CallInst *CI,
-                                   IRBuilder<> &B) {
-    // Check for a fixed format string.
-    StringRef FormatStr;
-    if (!getConstantStringInfo(CI->getArgOperand(1), FormatStr))
-      return nullptr;
+  // printf(format, ...) -> iprintf(format, ...) if no floating point
+  // arguments.
+  if (TLI->has(LibFunc::iprintf) && !callHasFloatingPointArgument(CI)) {
+    Module *M = B.GetInsertBlock()->getParent()->getParent();
+    Constant *IPrintFFn =
+        M->getOrInsertFunction("iprintf", FT, Callee->getAttributes());
+    CallInst *New = cast<CallInst>(CI->clone());
+    New->setCalledFunction(IPrintFFn);
+    B.Insert(New);
+    return New;
+  }
+  return nullptr;
+}
 
-    // If we just have a format string (nothing else crazy) transform it.
-    if (CI->getNumArgOperands() == 2) {
-      // Make sure there's no % in the constant array.  We could try to handle
-      // %% -> % in the future if we cared.
-      for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
-        if (FormatStr[i] == '%')
-          return nullptr; // we found a format specifier, bail out.
-
-      // These optimizations require DataLayout.
-      if (!DL) return nullptr;
-
-      // sprintf(str, fmt) -> llvm.memcpy(str, fmt, strlen(fmt)+1, 1)
-      B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
-                     ConstantInt::get(DL->getIntPtrType(*Context), // Copy the
-                                      FormatStr.size() + 1), 1);   // nul byte.
-      return ConstantInt::get(CI->getType(), FormatStr.size());
-    }
+Value *LibCallSimplifier::optimizeSPrintFString(CallInst *CI, IRBuilder<> &B) {
+  // Check for a fixed format string.
+  StringRef FormatStr;
+  if (!getConstantStringInfo(CI->getArgOperand(1), FormatStr))
+    return nullptr;
 
-    // The remaining optimizations require the format string to be "%s" or "%c"
-    // and have an extra operand.
-    if (FormatStr.size() != 2 || FormatStr[0] != '%' ||
-        CI->getNumArgOperands() < 3)
-      return nullptr;
+  // If we just have a format string (nothing else crazy) transform it.
+  if (CI->getNumArgOperands() == 2) {
+    // Make sure there's no % in the constant array.  We could try to handle
+    // %% -> % in the future if we cared.
+    for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
+      if (FormatStr[i] == '%')
+        return nullptr; // we found a format specifier, bail out.
 
-    // Decode the second character of the format string.
-    if (FormatStr[1] == 'c') {
-      // sprintf(dst, "%c", chr) --> *(i8*)dst = chr; *((i8*)dst+1) = 0
-      if (!CI->getArgOperand(2)->getType()->isIntegerTy()) return nullptr;
-      Value *V = B.CreateTrunc(CI->getArgOperand(2), B.getInt8Ty(), "char");
-      Value *Ptr = CastToCStr(CI->getArgOperand(0), B);
-      B.CreateStore(V, Ptr);
-      Ptr = B.CreateGEP(Ptr, B.getInt32(1), "nul");
-      B.CreateStore(B.getInt8(0), Ptr);
-
-      return ConstantInt::get(CI->getType(), 1);
-    }
+    // These optimizations require DataLayout.
+    if (!DL)
+      return nullptr;
 
-    if (FormatStr[1] == 's') {
-      // These optimizations require DataLayout.
-      if (!DL) return nullptr;
+    // sprintf(str, fmt) -> llvm.memcpy(str, fmt, strlen(fmt)+1, 1)
+    B.CreateMemCpy(
+        CI->getArgOperand(0), CI->getArgOperand(1),
+        ConstantInt::get(DL->getIntPtrType(CI->getContext()),
+                         FormatStr.size() + 1),
+        1); // Copy the null byte.
+    return ConstantInt::get(CI->getType(), FormatStr.size());
+  }
 
-      // sprintf(dest, "%s", str) -> llvm.memcpy(dest, str, strlen(str)+1, 1)
-      if (!CI->getArgOperand(2)->getType()->isPointerTy()) return nullptr;
+  // The remaining optimizations require the format string to be "%s" or "%c"
+  // and have an extra operand.
+  if (FormatStr.size() != 2 || FormatStr[0] != '%' ||
+      CI->getNumArgOperands() < 3)
+    return nullptr;
 
-      Value *Len = EmitStrLen(CI->getArgOperand(2), B, DL, TLI);
-      if (!Len)
-        return nullptr;
-      Value *IncLen = B.CreateAdd(Len,
-                                  ConstantInt::get(Len->getType(), 1),
-                                  "leninc");
-      B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(2), IncLen, 1);
+  // Decode the second character of the format string.
+  if (FormatStr[1] == 'c') {
+    // sprintf(dst, "%c", chr) --> *(i8*)dst = chr; *((i8*)dst+1) = 0
+    if (!CI->getArgOperand(2)->getType()->isIntegerTy())
+      return nullptr;
+    Value *V = B.CreateTrunc(CI->getArgOperand(2), B.getInt8Ty(), "char");
+    Value *Ptr = CastToCStr(CI->getArgOperand(0), B);
+    B.CreateStore(V, Ptr);
+    Ptr = B.CreateGEP(Ptr, B.getInt32(1), "nul");
+    B.CreateStore(B.getInt8(0), Ptr);
 
-      // The sprintf result is the unincremented number of bytes in the string.
-      return B.CreateIntCast(Len, CI->getType(), false);
-    }
-    return nullptr;
+    return ConstantInt::get(CI->getType(), 1);
   }
 
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    // Require two fixed pointer arguments and an integer result.
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
-        !FT->getParamType(1)->isPointerTy() ||
-        !FT->getReturnType()->isIntegerTy())
+  if (FormatStr[1] == 's') {
+    // These optimizations require DataLayout.
+    if (!DL)
       return nullptr;
 
-    if (Value *V = OptimizeFixedFormatString(Callee, CI, B)) {
-      return V;
-    }
+    // sprintf(dest, "%s", str) -> llvm.memcpy(dest, str, strlen(str)+1, 1)
+    if (!CI->getArgOperand(2)->getType()->isPointerTy())
+      return nullptr;
 
-    // sprintf(str, format, ...) -> siprintf(str, format, ...) if no floating
-    // point arguments.
-    if (TLI->has(LibFunc::siprintf) && !callHasFloatingPointArgument(CI)) {
-      Module *M = B.GetInsertBlock()->getParent()->getParent();
-      Constant *SIPrintFFn =
-        M->getOrInsertFunction("siprintf", FT, Callee->getAttributes());
-      CallInst *New = cast<CallInst>(CI->clone());
-      New->setCalledFunction(SIPrintFFn);
-      B.Insert(New);
-      return New;
-    }
-    return nullptr;
+    Value *Len = EmitStrLen(CI->getArgOperand(2), B, DL, TLI);
+    if (!Len)
+      return nullptr;
+    Value *IncLen =
+        B.CreateAdd(Len, ConstantInt::get(Len->getType(), 1), "leninc");
+    B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(2), IncLen, 1);
+
+    // The sprintf result is the unincremented number of bytes in the string.
+    return B.CreateIntCast(Len, CI->getType(), false);
   }
-};
+  return nullptr;
+}
 
-struct FPrintFOpt : public LibCallOptimization {
-  Value *optimizeFixedFormatString(Function *Callee, CallInst *CI,
-                                   IRBuilder<> &B) {
-    ErrorReportingOpt ER(/* StreamArg = */ 0);
-    (void) ER.callOptimizer(Callee, CI, B);
+Value *LibCallSimplifier::optimizeSPrintF(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  // Require two fixed pointer arguments and an integer result.
+  FunctionType *FT = Callee->getFunctionType();
+  if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
+      !FT->getParamType(1)->isPointerTy() ||
+      !FT->getReturnType()->isIntegerTy())
+    return nullptr;
 
-    // All the optimizations depend on the format string.
-    StringRef FormatStr;
-    if (!getConstantStringInfo(CI->getArgOperand(1), FormatStr))
-      return nullptr;
+  if (Value *V = optimizeSPrintFString(CI, B)) {
+    return V;
+  }
 
-    // Do not do any of the following transformations if the fprintf return
-    // value is used, in general the fprintf return value is not compatible
-    // with fwrite(), fputc() or fputs().
-    if (!CI->use_empty())
-      return nullptr;
+  // sprintf(str, format, ...) -> siprintf(str, format, ...) if no floating
+  // point arguments.
+  if (TLI->has(LibFunc::siprintf) && !callHasFloatingPointArgument(CI)) {
+    Module *M = B.GetInsertBlock()->getParent()->getParent();
+    Constant *SIPrintFFn =
+        M->getOrInsertFunction("siprintf", FT, Callee->getAttributes());
+    CallInst *New = cast<CallInst>(CI->clone());
+    New->setCalledFunction(SIPrintFFn);
+    B.Insert(New);
+    return New;
+  }
+  return nullptr;
+}
+
+Value *LibCallSimplifier::optimizeFPrintFString(CallInst *CI, IRBuilder<> &B) {
+  optimizeErrorReporting(CI, B, 0);
 
-    // fprintf(F, "foo") --> fwrite("foo", 3, 1, F)
-    if (CI->getNumArgOperands() == 2) {
-      for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
-        if (FormatStr[i] == '%')  // Could handle %% -> % if we cared.
-          return nullptr; // We found a format specifier.
+  // All the optimizations depend on the format string.
+  StringRef FormatStr;
+  if (!getConstantStringInfo(CI->getArgOperand(1), FormatStr))
+    return nullptr;
 
-      // These optimizations require DataLayout.
-      if (!DL) return nullptr;
+  // Do not do any of the following transformations if the fprintf return
+  // value is used, in general the fprintf return value is not compatible
+  // with fwrite(), fputc() or fputs().
+  if (!CI->use_empty())
+    return nullptr;
 
-      return EmitFWrite(CI->getArgOperand(1),
-                        ConstantInt::get(DL->getIntPtrType(*Context),
-                                         FormatStr.size()),
-                        CI->getArgOperand(0), B, DL, TLI);
-    }
+  // fprintf(F, "foo") --> fwrite("foo", 3, 1, F)
+  if (CI->getNumArgOperands() == 2) {
+    for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
+      if (FormatStr[i] == '%') // Could handle %% -> % if we cared.
+        return nullptr;        // We found a format specifier.
 
-    // The remaining optimizations require the format string to be "%s" or "%c"
-    // and have an extra operand.
-    if (FormatStr.size() != 2 || FormatStr[0] != '%' ||
-        CI->getNumArgOperands() < 3)
+    // These optimizations require DataLayout.
+    if (!DL)
       return nullptr;
 
-    // Decode the second character of the format string.
-    if (FormatStr[1] == 'c') {
-      // fprintf(F, "%c", chr) --> fputc(chr, F)
-      if (!CI->getArgOperand(2)->getType()->isIntegerTy()) return nullptr;
-      return EmitFPutC(CI->getArgOperand(2), CI->getArgOperand(0), B, DL, TLI);
-    }
+    return EmitFWrite(
+        CI->getArgOperand(1),
+        ConstantInt::get(DL->getIntPtrType(CI->getContext()), FormatStr.size()),
+        CI->getArgOperand(0), B, DL, TLI);
+  }
 
-    if (FormatStr[1] == 's') {
-      // fprintf(F, "%s", str) --> fputs(str, F)
-      if (!CI->getArgOperand(2)->getType()->isPointerTy())
-        return nullptr;
-      return EmitFPutS(CI->getArgOperand(2), CI->getArgOperand(0), B, DL, TLI);
-    }
+  // The remaining optimizations require the format string to be "%s" or "%c"
+  // and have an extra operand.
+  if (FormatStr.size() != 2 || FormatStr[0] != '%' ||
+      CI->getNumArgOperands() < 3)
     return nullptr;
-  }
 
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    // Require two fixed paramters as pointers and integer result.
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
-        !FT->getParamType(1)->isPointerTy() ||
-        !FT->getReturnType()->isIntegerTy())
+  // Decode the second character of the format string.
+  if (FormatStr[1] == 'c') {
+    // fprintf(F, "%c", chr) --> fputc(chr, F)
+    if (!CI->getArgOperand(2)->getType()->isIntegerTy())
       return nullptr;
+    return EmitFPutC(CI->getArgOperand(2), CI->getArgOperand(0), B, DL, TLI);
+  }
 
-    if (Value *V = optimizeFixedFormatString(Callee, CI, B)) {
-      return V;
-    }
+  if (FormatStr[1] == 's') {
+    // fprintf(F, "%s", str) --> fputs(str, F)
+    if (!CI->getArgOperand(2)->getType()->isPointerTy())
+      return nullptr;
+    return EmitFPutS(CI->getArgOperand(2), CI->getArgOperand(0), B, DL, TLI);
+  }
+  return nullptr;
+}
 
-    // fprintf(stream, format, ...) -> fiprintf(stream, format, ...) if no
-    // floating point arguments.
-    if (TLI->has(LibFunc::fiprintf) && !callHasFloatingPointArgument(CI)) {
-      Module *M = B.GetInsertBlock()->getParent()->getParent();
-      Constant *FIPrintFFn =
-        M->getOrInsertFunction("fiprintf", FT, Callee->getAttributes());
-      CallInst *New = cast<CallInst>(CI->clone());
-      New->setCalledFunction(FIPrintFFn);
-      B.Insert(New);
-      return New;
-    }
+Value *LibCallSimplifier::optimizeFPrintF(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  // Require two fixed paramters as pointers and integer result.
+  FunctionType *FT = Callee->getFunctionType();
+  if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
+      !FT->getParamType(1)->isPointerTy() ||
+      !FT->getReturnType()->isIntegerTy())
     return nullptr;
+
+  if (Value *V = optimizeFPrintFString(CI, B)) {
+    return V;
   }
-};
 
-struct FWriteOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    ErrorReportingOpt ER(/* StreamArg = */ 3);
-    (void) ER.callOptimizer(Callee, CI, B);
+  // fprintf(stream, format, ...) -> fiprintf(stream, format, ...) if no
+  // floating point arguments.
+  if (TLI->has(LibFunc::fiprintf) && !callHasFloatingPointArgument(CI)) {
+    Module *M = B.GetInsertBlock()->getParent()->getParent();
+    Constant *FIPrintFFn =
+        M->getOrInsertFunction("fiprintf", FT, Callee->getAttributes());
+    CallInst *New = cast<CallInst>(CI->clone());
+    New->setCalledFunction(FIPrintFFn);
+    B.Insert(New);
+    return New;
+  }
+  return nullptr;
+}
 
-    // Require a pointer, an integer, an integer, a pointer, returning integer.
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 4 || !FT->getParamType(0)->isPointerTy() ||
-        !FT->getParamType(1)->isIntegerTy() ||
-        !FT->getParamType(2)->isIntegerTy() ||
-        !FT->getParamType(3)->isPointerTy() ||
-        !FT->getReturnType()->isIntegerTy())
-      return nullptr;
+Value *LibCallSimplifier::optimizeFWrite(CallInst *CI, IRBuilder<> &B) {
+  optimizeErrorReporting(CI, B, 3);
 
-    // Get the element size and count.
-    ConstantInt *SizeC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
-    ConstantInt *CountC = dyn_cast<ConstantInt>(CI->getArgOperand(2));
-    if (!SizeC || !CountC) return nullptr;
-    uint64_t Bytes = SizeC->getZExtValue()*CountC->getZExtValue();
-
-    // If this is writing zero records, remove the call (it's a noop).
-    if (Bytes == 0)
-      return ConstantInt::get(CI->getType(), 0);
-
-    // If this is writing one byte, turn it into fputc.
-    // This optimisation is only valid, if the return value is unused.
-    if (Bytes == 1 && CI->use_empty()) {  // fwrite(S,1,1,F) -> fputc(S[0],F)
-      Value *Char = B.CreateLoad(CastToCStr(CI->getArgOperand(0), B), "char");
-      Value *NewCI = EmitFPutC(Char, CI->getArgOperand(3), B, DL, TLI);
-      return NewCI ? ConstantInt::get(CI->getType(), 1) : nullptr;
-    }
+  Function *Callee = CI->getCalledFunction();
+  // Require a pointer, an integer, an integer, a pointer, returning integer.
+  FunctionType *FT = Callee->getFunctionType();
+  if (FT->getNumParams() != 4 || !FT->getParamType(0)->isPointerTy() ||
+      !FT->getParamType(1)->isIntegerTy() ||
+      !FT->getParamType(2)->isIntegerTy() ||
+      !FT->getParamType(3)->isPointerTy() ||
+      !FT->getReturnType()->isIntegerTy())
+    return nullptr;
 
+  // Get the element size and count.
+  ConstantInt *SizeC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
+  ConstantInt *CountC = dyn_cast<ConstantInt>(CI->getArgOperand(2));
+  if (!SizeC || !CountC)
     return nullptr;
-  }
-};
+  uint64_t Bytes = SizeC->getZExtValue() * CountC->getZExtValue();
 
-struct FPutsOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    ErrorReportingOpt ER(/* StreamArg = */ 1);
-    (void) ER.callOptimizer(Callee, CI, B);
+  // If this is writing zero records, remove the call (it's a noop).
+  if (Bytes == 0)
+    return ConstantInt::get(CI->getType(), 0);
 
-    // These optimizations require DataLayout.
-    if (!DL) return nullptr;
+  // If this is writing one byte, turn it into fputc.
+  // This optimisation is only valid, if the return value is unused.
+  if (Bytes == 1 && CI->use_empty()) { // fwrite(S,1,1,F) -> fputc(S[0],F)
+    Value *Char = B.CreateLoad(CastToCStr(CI->getArgOperand(0), B), "char");
+    Value *NewCI = EmitFPutC(Char, CI->getArgOperand(3), B, DL, TLI);
+    return NewCI ? ConstantInt::get(CI->getType(), 1) : nullptr;
+  }
 
-    // Require two pointers.  Also, we can't optimize if return value is used.
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
-        !FT->getParamType(1)->isPointerTy() ||
-        !CI->use_empty())
-      return nullptr;
+  return nullptr;
+}
 
-    // fputs(s,F) --> fwrite(s,1,strlen(s),F)
-    uint64_t Len = GetStringLength(CI->getArgOperand(0));
-    if (!Len) return nullptr;
-    // Known to have no uses (see above).
-    return EmitFWrite(CI->getArgOperand(0),
-                      ConstantInt::get(DL->getIntPtrType(*Context), Len-1),
-                      CI->getArgOperand(1), B, DL, TLI);
-  }
-};
-
-struct PutsOpt : public LibCallOptimization {
-  Value *callOptimizer(Function *Callee, CallInst *CI,
-                       IRBuilder<> &B) override {
-    // Require one fixed pointer argument and an integer/void result.
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() < 1 || !FT->getParamType(0)->isPointerTy() ||
-        !(FT->getReturnType()->isIntegerTy() ||
-          FT->getReturnType()->isVoidTy()))
-      return nullptr;
+Value *LibCallSimplifier::optimizeFPuts(CallInst *CI, IRBuilder<> &B) {
+  optimizeErrorReporting(CI, B, 1);
 
-    // Check for a constant string.
-    StringRef Str;
-    if (!getConstantStringInfo(CI->getArgOperand(0), Str))
-      return nullptr;
+  Function *Callee = CI->getCalledFunction();
 
-    if (Str.empty() && CI->use_empty()) {
-      // puts("") -> putchar('\n')
-      Value *Res = EmitPutChar(B.getInt32('\n'), B, DL, TLI);
-      if (CI->use_empty() || !Res) return Res;
-      return B.CreateIntCast(Res, CI->getType(), true);
-    }
+  // These optimizations require DataLayout.
+  if (!DL)
+    return nullptr;
 
+  // Require two pointers.  Also, we can't optimize if return value is used.
+  FunctionType *FT = Callee->getFunctionType();
+  if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
+      !FT->getParamType(1)->isPointerTy() || !CI->use_empty())
+    return nullptr;
+
+  // fputs(s,F) --> fwrite(s,1,strlen(s),F)
+  uint64_t Len = GetStringLength(CI->getArgOperand(0));
+  if (!Len)
     return nullptr;
-  }
-};
 
-} // End anonymous namespace.
+  // Known to have no uses (see above).
+  return EmitFWrite(
+      CI->getArgOperand(0),
+      ConstantInt::get(DL->getIntPtrType(CI->getContext()), Len - 1),
+      CI->getArgOperand(1), B, DL, TLI);
+}
 
-namespace llvm {
+Value *LibCallSimplifier::optimizePuts(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  // Require one fixed pointer argument and an integer/void result.
+  FunctionType *FT = Callee->getFunctionType();
+  if (FT->getNumParams() < 1 || !FT->getParamType(0)->isPointerTy() ||
+      !(FT->getReturnType()->isIntegerTy() || FT->getReturnType()->isVoidTy()))
+    return nullptr;
 
-class LibCallSimplifierImpl {
-  const DataLayout *DL;
-  const TargetLibraryInfo *TLI;
-  const LibCallSimplifier *LCS;
-  bool UnsafeFPShrink;
+  // Check for a constant string.
+  StringRef Str;
+  if (!getConstantStringInfo(CI->getArgOperand(0), Str))
+    return nullptr;
 
-  // Math library call optimizations.
-  CosOpt Cos;
-  PowOpt Pow;
-  Exp2Opt Exp2;
-public:
-  LibCallSimplifierImpl(const DataLayout *DL, const TargetLibraryInfo *TLI,
-                        const LibCallSimplifier *LCS,
-                        bool UnsafeFPShrink = false)
-    : Cos(UnsafeFPShrink), Pow(UnsafeFPShrink), Exp2(UnsafeFPShrink) {
-    this->DL = DL;
-    this->TLI = TLI;
-    this->LCS = LCS;
-    this->UnsafeFPShrink = UnsafeFPShrink;
+  if (Str.empty() && CI->use_empty()) {
+    // puts("") -> putchar('\n')
+    Value *Res = EmitPutChar(B.getInt32('\n'), B, DL, TLI);
+    if (CI->use_empty() || !Res)
+      return Res;
+    return B.CreateIntCast(Res, CI->getType(), true);
   }
 
-  Value *optimizeCall(CallInst *CI);
-  LibCallOptimization *lookupOptimization(CallInst *CI);
-  bool hasFloatVersion(StringRef FuncName);
-};
+  return nullptr;
+}
 
-bool LibCallSimplifierImpl::hasFloatVersion(StringRef FuncName) {
+bool LibCallSimplifier::hasFloatVersion(StringRef FuncName) {
   LibFunc::Func Func;
   SmallString<20> FloatFuncName = FuncName;
   FloatFuncName += 'f';
@@ -2048,263 +1857,239 @@ bool LibCallSimplifierImpl::hasFloatVersion(StringRef FuncName) {
   return false;
 }
 
-// Fortified library call optimizations.
-static MemCpyChkOpt MemCpyChk;
-static MemMoveChkOpt MemMoveChk;
-static MemSetChkOpt MemSetChk;
-static StrCpyChkOpt StrCpyChk;
-static StpCpyChkOpt StpCpyChk;
-static StrNCpyChkOpt StrNCpyChk;
-
-// String library call optimizations.
-static StrCatOpt StrCat;
-static StrNCatOpt StrNCat;
-static StrChrOpt StrChr;
-static StrRChrOpt StrRChr;
-static StrCmpOpt StrCmp;
-static StrNCmpOpt StrNCmp;
-static StrCpyOpt StrCpy;
-static StpCpyOpt StpCpy;
-static StrNCpyOpt StrNCpy;
-static StrLenOpt StrLen;
-static StrPBrkOpt StrPBrk;
-static StrToOpt StrTo;
-static StrSpnOpt StrSpn;
-static StrCSpnOpt StrCSpn;
-static StrStrOpt StrStr;
-
-// Memory library call optimizations.
-static MemCmpOpt MemCmp;
-static MemCpyOpt MemCpy;
-static MemMoveOpt MemMove;
-static MemSetOpt MemSet;
-
-// Math library call optimizations.
-static UnaryDoubleFPOpt UnaryDoubleFP(false);
-static BinaryDoubleFPOpt BinaryDoubleFP(false);
-static UnaryDoubleFPOpt UnsafeUnaryDoubleFP(true);
-static SinCosPiOpt SinCosPi;
-
-  // Integer library call optimizations.
-static FFSOpt FFS;
-static AbsOpt Abs;
-static IsDigitOpt IsDigit;
-static IsAsciiOpt IsAscii;
-static ToAsciiOpt ToAscii;
-
-// Formatting and IO library call optimizations.
-static ErrorReportingOpt ErrorReporting;
-static ErrorReportingOpt ErrorReporting0(0);
-static ErrorReportingOpt ErrorReporting1(1);
-static PrintFOpt PrintF;
-static SPrintFOpt SPrintF;
-static FPrintFOpt FPrintF;
-static FWriteOpt FWrite;
-static FPutsOpt FPuts;
-static PutsOpt Puts;
-
-LibCallOptimization *LibCallSimplifierImpl::lookupOptimization(CallInst *CI) {
+Value *LibCallSimplifier::optimizeStringMemoryLibCall(CallInst *CI,
+                                                      IRBuilder<> &Builder) {
+  LibFunc::Func Func;
+  Function *Callee = CI->getCalledFunction();
+  StringRef FuncName = Callee->getName();
+
+  // Check for string/memory library functions.
+  if (TLI->getLibFunc(FuncName, Func) && TLI->has(Func)) {
+    // Make sure we never change the calling convention.
+    assert((ignoreCallingConv(Func) ||
+            CI->getCallingConv() == llvm::CallingConv::C) &&
+      "Optimizing string/memory libcall would change the calling convention");
+    switch (Func) {
+    case LibFunc::strcat:
+      return optimizeStrCat(CI, Builder);
+    case LibFunc::strncat:
+      return optimizeStrNCat(CI, Builder);
+    case LibFunc::strchr:
+      return optimizeStrChr(CI, Builder);
+    case LibFunc::strrchr:
+      return optimizeStrRChr(CI, Builder);
+    case LibFunc::strcmp:
+      return optimizeStrCmp(CI, Builder);
+    case LibFunc::strncmp:
+      return optimizeStrNCmp(CI, Builder);
+    case LibFunc::strcpy:
+      return optimizeStrCpy(CI, Builder);
+    case LibFunc::stpcpy:
+      return optimizeStpCpy(CI, Builder);
+    case LibFunc::strncpy:
+      return optimizeStrNCpy(CI, Builder);
+    case LibFunc::strlen:
+      return optimizeStrLen(CI, Builder);
+    case LibFunc::strpbrk:
+      return optimizeStrPBrk(CI, Builder);
+    case LibFunc::strtol:
+    case LibFunc::strtod:
+    case LibFunc::strtof:
+    case LibFunc::strtoul:
+    case LibFunc::strtoll:
+    case LibFunc::strtold:
+    case LibFunc::strtoull:
+      return optimizeStrTo(CI, Builder);
+    case LibFunc::strspn:
+      return optimizeStrSpn(CI, Builder);
+    case LibFunc::strcspn:
+      return optimizeStrCSpn(CI, Builder);
+    case LibFunc::strstr:
+      return optimizeStrStr(CI, Builder);
+    case LibFunc::memcmp:
+      return optimizeMemCmp(CI, Builder);
+    case LibFunc::memcpy:
+      return optimizeMemCpy(CI, Builder);
+    case LibFunc::memmove:
+      return optimizeMemMove(CI, Builder);
+    case LibFunc::memset:
+      return optimizeMemSet(CI, Builder);
+    default:
+      break;
+    }
+  }
+  return nullptr;
+}
+
+Value *LibCallSimplifier::optimizeCall(CallInst *CI) {
+  if (CI->isNoBuiltin())
+    return nullptr;
+
   LibFunc::Func Func;
   Function *Callee = CI->getCalledFunction();
   StringRef FuncName = Callee->getName();
+  IRBuilder<> Builder(CI);
+  bool isCallingConvC = CI->getCallingConv() == llvm::CallingConv::C;
+
+  // Command-line parameter overrides function attribute.
+  if (EnableUnsafeFPShrink.getNumOccurrences() > 0)
+    UnsafeFPShrink = EnableUnsafeFPShrink;
+  else if (Callee->hasFnAttribute("unsafe-fp-math")) {
+    // FIXME: This is the same problem as described in optimizeSqrt().
+    // If calls gain access to IR-level FMF, then use that instead of a
+    // function attribute.
+
+    // Check for unsafe-fp-math = true.
+    Attribute Attr = Callee->getFnAttribute("unsafe-fp-math");
+    if (Attr.getValueAsString() == "true")
+      UnsafeFPShrink = true;
+  }
 
-  // Next check for intrinsics.
+  // First, check for intrinsics.
   if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(CI)) {
+    if (!isCallingConvC)
+      return nullptr;
     switch (II->getIntrinsicID()) {
     case Intrinsic::pow:
-       return &Pow;
+      return optimizePow(CI, Builder);
     case Intrinsic::exp2:
-       return &Exp2;
+      return optimizeExp2(CI, Builder);
+    case Intrinsic::fabs:
+      return optimizeFabs(CI, Builder);
+    case Intrinsic::sqrt:
+      return optimizeSqrt(CI, Builder);
     default:
-       return nullptr;
+      return nullptr;
     }
   }
 
+  // Also try to simplify calls to fortified library functions.
+  if (Value *SimplifiedFortifiedCI = FortifiedSimplifier.optimizeCall(CI)) {
+    // Try to further simplify the result.
+    CallInst *SimplifiedCI = dyn_cast<CallInst>(SimplifiedFortifiedCI);
+    if (SimplifiedCI && SimplifiedCI->getCalledFunction())
+      if (Value *V = optimizeStringMemoryLibCall(SimplifiedCI, Builder))
+        return V;
+    return SimplifiedFortifiedCI;
+  }
+
   // Then check for known library functions.
   if (TLI->getLibFunc(FuncName, Func) && TLI->has(Func)) {
+    // We never change the calling convention.
+    if (!ignoreCallingConv(Func) && !isCallingConvC)
+      return nullptr;
+    if (Value *V = optimizeStringMemoryLibCall(CI, Builder))
+      return V;
     switch (Func) {
-      case LibFunc::strcat:
-        return &StrCat;
-      case LibFunc::strncat:
-        return &StrNCat;
-      case LibFunc::strchr:
-        return &StrChr;
-      case LibFunc::strrchr:
-        return &StrRChr;
-      case LibFunc::strcmp:
-        return &StrCmp;
-      case LibFunc::strncmp:
-        return &StrNCmp;
-      case LibFunc::strcpy:
-        return &StrCpy;
-      case LibFunc::stpcpy:
-        return &StpCpy;
-      case LibFunc::strncpy:
-        return &StrNCpy;
-      case LibFunc::strlen:
-        return &StrLen;
-      case LibFunc::strpbrk:
-        return &StrPBrk;
-      case LibFunc::strtol:
-      case LibFunc::strtod:
-      case LibFunc::strtof:
-      case LibFunc::strtoul:
-      case LibFunc::strtoll:
-      case LibFunc::strtold:
-      case LibFunc::strtoull:
-        return &StrTo;
-      case LibFunc::strspn:
-        return &StrSpn;
-      case LibFunc::strcspn:
-        return &StrCSpn;
-      case LibFunc::strstr:
-        return &StrStr;
-      case LibFunc::memcmp:
-        return &MemCmp;
-      case LibFunc::memcpy:
-        return &MemCpy;
-      case LibFunc::memmove:
-        return &MemMove;
-      case LibFunc::memset:
-        return &MemSet;
-      case LibFunc::cosf:
-      case LibFunc::cos:
-      case LibFunc::cosl:
-        return &Cos;
-      case LibFunc::sinpif:
-      case LibFunc::sinpi:
-      case LibFunc::cospif:
-      case LibFunc::cospi:
-        return &SinCosPi;
-      case LibFunc::powf:
-      case LibFunc::pow:
-      case LibFunc::powl:
-        return &Pow;
-      case LibFunc::exp2l:
-      case LibFunc::exp2:
-      case LibFunc::exp2f:
-        return &Exp2;
-      case LibFunc::ffs:
-      case LibFunc::ffsl:
-      case LibFunc::ffsll:
-        return &FFS;
-      case LibFunc::abs:
-      case LibFunc::labs:
-      case LibFunc::llabs:
-        return &Abs;
-      case LibFunc::isdigit:
-        return &IsDigit;
-      case LibFunc::isascii:
-        return &IsAscii;
-      case LibFunc::toascii:
-        return &ToAscii;
-      case LibFunc::printf:
-        return &PrintF;
-      case LibFunc::sprintf:
-        return &SPrintF;
-      case LibFunc::fprintf:
-        return &FPrintF;
-      case LibFunc::fwrite:
-        return &FWrite;
-      case LibFunc::fputs:
-        return &FPuts;
-      case LibFunc::puts:
-        return &Puts;
-      case LibFunc::perror:
-        return &ErrorReporting;
-      case LibFunc::vfprintf:
-      case LibFunc::fiprintf:
-        return &ErrorReporting0;
-      case LibFunc::fputc:
-        return &ErrorReporting1;
-      case LibFunc::ceil:
-      case LibFunc::fabs:
-      case LibFunc::floor:
-      case LibFunc::rint:
-      case LibFunc::round:
-      case LibFunc::nearbyint:
-      case LibFunc::trunc:
-        if (hasFloatVersion(FuncName))
-          return &UnaryDoubleFP;
-        return nullptr;
-      case LibFunc::acos:
-      case LibFunc::acosh:
-      case LibFunc::asin:
-      case LibFunc::asinh:
-      case LibFunc::atan:
-      case LibFunc::atanh:
-      case LibFunc::cbrt:
-      case LibFunc::cosh:
-      case LibFunc::exp:
-      case LibFunc::exp10:
-      case LibFunc::expm1:
-      case LibFunc::log:
-      case LibFunc::log10:
-      case LibFunc::log1p:
-      case LibFunc::log2:
-      case LibFunc::logb:
-      case LibFunc::sin:
-      case LibFunc::sinh:
-      case LibFunc::sqrt:
-      case LibFunc::tan:
-      case LibFunc::tanh:
-        if (UnsafeFPShrink && hasFloatVersion(FuncName))
-         return &UnsafeUnaryDoubleFP;
-        return nullptr;
-      case LibFunc::fmin:
-      case LibFunc::fmax:
-        if (hasFloatVersion(FuncName))
-          return &BinaryDoubleFP;
-        return nullptr;
-      case LibFunc::memcpy_chk:
-        return &MemCpyChk;
-      default:
-        return nullptr;
-      }
-  }
-
-  // Finally check for fortified library calls.
-  if (FuncName.endswith("_chk")) {
-    if (FuncName == "__memmove_chk")
-      return &MemMoveChk;
-    else if (FuncName == "__memset_chk")
-      return &MemSetChk;
-    else if (FuncName == "__strcpy_chk")
-      return &StrCpyChk;
-    else if (FuncName == "__stpcpy_chk")
-      return &StpCpyChk;
-    else if (FuncName == "__strncpy_chk")
-      return &StrNCpyChk;
-    else if (FuncName == "__stpncpy_chk")
-      return &StrNCpyChk;
-  }
-
-  return nullptr;
-
-}
-
-Value *LibCallSimplifierImpl::optimizeCall(CallInst *CI) {
-  LibCallOptimization *LCO = lookupOptimization(CI);
-  if (LCO) {
-    IRBuilder<> Builder(CI);
-    return LCO->optimizeCall(CI, DL, TLI, LCS, Builder);
+    case LibFunc::cosf:
+    case LibFunc::cos:
+    case LibFunc::cosl:
+      return optimizeCos(CI, Builder);
+    case LibFunc::sinpif:
+    case LibFunc::sinpi:
+    case LibFunc::cospif:
+    case LibFunc::cospi:
+      return optimizeSinCosPi(CI, Builder);
+    case LibFunc::powf:
+    case LibFunc::pow:
+    case LibFunc::powl:
+      return optimizePow(CI, Builder);
+    case LibFunc::exp2l:
+    case LibFunc::exp2:
+    case LibFunc::exp2f:
+      return optimizeExp2(CI, Builder);
+    case LibFunc::fabsf:
+    case LibFunc::fabs:
+    case LibFunc::fabsl:
+      return optimizeFabs(CI, Builder);
+    case LibFunc::sqrtf:
+    case LibFunc::sqrt:
+    case LibFunc::sqrtl:
+      return optimizeSqrt(CI, Builder);
+    case LibFunc::ffs:
+    case LibFunc::ffsl:
+    case LibFunc::ffsll:
+      return optimizeFFS(CI, Builder);
+    case LibFunc::abs:
+    case LibFunc::labs:
+    case LibFunc::llabs:
+      return optimizeAbs(CI, Builder);
+    case LibFunc::isdigit:
+      return optimizeIsDigit(CI, Builder);
+    case LibFunc::isascii:
+      return optimizeIsAscii(CI, Builder);
+    case LibFunc::toascii:
+      return optimizeToAscii(CI, Builder);
+    case LibFunc::printf:
+      return optimizePrintF(CI, Builder);
+    case LibFunc::sprintf:
+      return optimizeSPrintF(CI, Builder);
+    case LibFunc::fprintf:
+      return optimizeFPrintF(CI, Builder);
+    case LibFunc::fwrite:
+      return optimizeFWrite(CI, Builder);
+    case LibFunc::fputs:
+      return optimizeFPuts(CI, Builder);
+    case LibFunc::puts:
+      return optimizePuts(CI, Builder);
+    case LibFunc::perror:
+      return optimizeErrorReporting(CI, Builder);
+    case LibFunc::vfprintf:
+    case LibFunc::fiprintf:
+      return optimizeErrorReporting(CI, Builder, 0);
+    case LibFunc::fputc:
+      return optimizeErrorReporting(CI, Builder, 1);
+    case LibFunc::ceil:
+    case LibFunc::floor:
+    case LibFunc::rint:
+    case LibFunc::round:
+    case LibFunc::nearbyint:
+    case LibFunc::trunc:
+      if (hasFloatVersion(FuncName))
+        return optimizeUnaryDoubleFP(CI, Builder, false);
+      return nullptr;
+    case LibFunc::acos:
+    case LibFunc::acosh:
+    case LibFunc::asin:
+    case LibFunc::asinh:
+    case LibFunc::atan:
+    case LibFunc::atanh:
+    case LibFunc::cbrt:
+    case LibFunc::cosh:
+    case LibFunc::exp:
+    case LibFunc::exp10:
+    case LibFunc::expm1:
+    case LibFunc::log:
+    case LibFunc::log10:
+    case LibFunc::log1p:
+    case LibFunc::log2:
+    case LibFunc::logb:
+    case LibFunc::sin:
+    case LibFunc::sinh:
+    case LibFunc::tan:
+    case LibFunc::tanh:
+      if (UnsafeFPShrink && hasFloatVersion(FuncName))
+        return optimizeUnaryDoubleFP(CI, Builder, true);
+      return nullptr;
+    case LibFunc::copysign:
+    case LibFunc::fmin:
+    case LibFunc::fmax:
+      if (hasFloatVersion(FuncName))
+        return optimizeBinaryDoubleFP(CI, Builder);
+      return nullptr;
+    default:
+      return nullptr;
+    }
   }
   return nullptr;
 }
 
 LibCallSimplifier::LibCallSimplifier(const DataLayout *DL,
-                                     const TargetLibraryInfo *TLI,
-                                     bool UnsafeFPShrink) {
-  Impl = new LibCallSimplifierImpl(DL, TLI, this, UnsafeFPShrink);
-}
-
-LibCallSimplifier::~LibCallSimplifier() {
-  delete Impl;
-}
-
-Value *LibCallSimplifier::optimizeCall(CallInst *CI) {
-  if (CI->isNoBuiltin()) return nullptr;
-  return Impl->optimizeCall(CI);
+                                     const TargetLibraryInfo *TLI) :
+                                     FortifiedSimplifier(DL, TLI),
+                                     DL(DL),
+                                     TLI(TLI),
+                                     UnsafeFPShrink(false) {
 }
 
 void LibCallSimplifier::replaceAllUsesWith(Instruction *I, Value *With) const {
@@ -2312,8 +2097,6 @@ void LibCallSimplifier::replaceAllUsesWith(Instruction *I, Value *With) const {
   I->eraseFromParent();
 }
 
-}
-
 // TODO:
 //   Additional cases that we need to add to this file:
 //
@@ -2361,3 +2144,184 @@ void LibCallSimplifier::replaceAllUsesWith(Instruction *I, Value *With) const {
 //   * trunc(cnst) -> cnst'
 //
 //
+
+//===----------------------------------------------------------------------===//
+// Fortified Library Call Optimizations
+//===----------------------------------------------------------------------===//
+
+bool FortifiedLibCallSimplifier::isFortifiedCallFoldable(CallInst *CI,
+                                                         unsigned ObjSizeOp,
+                                                         unsigned SizeOp,
+                                                         bool isString) {
+  if (CI->getArgOperand(ObjSizeOp) == CI->getArgOperand(SizeOp))
+    return true;
+  if (ConstantInt *ObjSizeCI =
+          dyn_cast<ConstantInt>(CI->getArgOperand(ObjSizeOp))) {
+    if (ObjSizeCI->isAllOnesValue())
+      return true;
+    // If the object size wasn't -1 (unknown), bail out if we were asked to.
+    if (OnlyLowerUnknownSize)
+      return false;
+    if (isString) {
+      uint64_t Len = GetStringLength(CI->getArgOperand(SizeOp));
+      // If the length is 0 we don't know how long it is and so we can't
+      // remove the check.
+      if (Len == 0)
+        return false;
+      return ObjSizeCI->getZExtValue() >= Len;
+    }
+    if (ConstantInt *SizeCI = dyn_cast<ConstantInt>(CI->getArgOperand(SizeOp)))
+      return ObjSizeCI->getZExtValue() >= SizeCI->getZExtValue();
+  }
+  return false;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeMemCpyChk(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+
+  if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memcpy_chk, DL))
+    return nullptr;
+
+  if (isFortifiedCallFoldable(CI, 3, 2, false)) {
+    B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
+                   CI->getArgOperand(2), 1);
+    return CI->getArgOperand(0);
+  }
+  return nullptr;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeMemMoveChk(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+
+  if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memmove_chk, DL))
+    return nullptr;
+
+  if (isFortifiedCallFoldable(CI, 3, 2, false)) {
+    B.CreateMemMove(CI->getArgOperand(0), CI->getArgOperand(1),
+                    CI->getArgOperand(2), 1);
+    return CI->getArgOperand(0);
+  }
+  return nullptr;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeMemSetChk(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+
+  if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memset_chk, DL))
+    return nullptr;
+
+  if (isFortifiedCallFoldable(CI, 3, 2, false)) {
+    Value *Val = B.CreateIntCast(CI->getArgOperand(1), B.getInt8Ty(), false);
+    B.CreateMemSet(CI->getArgOperand(0), Val, CI->getArgOperand(2), 1);
+    return CI->getArgOperand(0);
+  }
+  return nullptr;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeStrCpyChk(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  StringRef Name = Callee->getName();
+  LibFunc::Func Func =
+      Name.startswith("str") ? LibFunc::strcpy_chk : LibFunc::stpcpy_chk;
+
+  if (!checkStringCopyLibFuncSignature(Callee, Func, DL))
+    return nullptr;
+
+  Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1),
+        *ObjSize = CI->getArgOperand(2);
+
+  // __stpcpy_chk(x,x,...)  -> x+strlen(x)
+  if (!OnlyLowerUnknownSize && Dst == Src) {
+    Value *StrLen = EmitStrLen(Src, B, DL, TLI);
+    return StrLen ? B.CreateInBoundsGEP(Dst, StrLen) : nullptr;
+  }
+
+  // If a) we don't have any length information, or b) we know this will
+  // fit then just lower to a plain st[rp]cpy. Otherwise we'll keep our
+  // st[rp]cpy_chk call which may fail at runtime if the size is too long.
+  // TODO: It might be nice to get a maximum length out of the possible
+  // string lengths for varying.
+  if (isFortifiedCallFoldable(CI, 2, 1, true)) {
+    Value *Ret = EmitStrCpy(Dst, Src, B, DL, TLI, Name.substr(2, 6));
+    return Ret;
+  } else if (!OnlyLowerUnknownSize) {
+    // Maybe we can stil fold __st[rp]cpy_chk to __memcpy_chk.
+    uint64_t Len = GetStringLength(Src);
+    if (Len == 0)
+      return nullptr;
+
+    // This optimization requires DataLayout.
+    if (!DL)
+      return nullptr;
+
+    Type *SizeTTy = DL->getIntPtrType(CI->getContext());
+    Value *LenV = ConstantInt::get(SizeTTy, Len);
+    Value *Ret = EmitMemCpyChk(Dst, Src, LenV, ObjSize, B, DL, TLI);
+    // If the function was an __stpcpy_chk, and we were able to fold it into
+    // a __memcpy_chk, we still need to return the correct end pointer.
+    if (Ret && Func == LibFunc::stpcpy_chk)
+      return B.CreateGEP(Dst, ConstantInt::get(SizeTTy, Len - 1));
+    return Ret;
+  }
+  return nullptr;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeStrNCpyChk(CallInst *CI, IRBuilder<> &B) {
+  Function *Callee = CI->getCalledFunction();
+  StringRef Name = Callee->getName();
+  LibFunc::Func Func =
+      Name.startswith("str") ? LibFunc::strncpy_chk : LibFunc::stpncpy_chk;
+
+  if (!checkStringCopyLibFuncSignature(Callee, Func, DL))
+    return nullptr;
+  if (isFortifiedCallFoldable(CI, 3, 2, false)) {
+    Value *Ret =
+        EmitStrNCpy(CI->getArgOperand(0), CI->getArgOperand(1),
+                    CI->getArgOperand(2), B, DL, TLI, Name.substr(2, 7));
+    return Ret;
+  }
+  return nullptr;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeCall(CallInst *CI) {
+  if (CI->isNoBuiltin())
+    return nullptr;
+
+  LibFunc::Func Func;
+  Function *Callee = CI->getCalledFunction();
+  StringRef FuncName = Callee->getName();
+  IRBuilder<> Builder(CI);
+  bool isCallingConvC = CI->getCallingConv() == llvm::CallingConv::C;
+
+  // First, check that this is a known library functions.
+  if (!TLI->getLibFunc(FuncName, Func) || !TLI->has(Func))
+    return nullptr;
+
+  // We never change the calling convention.
+  if (!ignoreCallingConv(Func) && !isCallingConvC)
+    return nullptr;
+
+  switch (Func) {
+  case LibFunc::memcpy_chk:
+    return optimizeMemCpyChk(CI, Builder);
+  case LibFunc::memmove_chk:
+    return optimizeMemMoveChk(CI, Builder);
+  case LibFunc::memset_chk:
+    return optimizeMemSetChk(CI, Builder);
+  case LibFunc::stpcpy_chk:
+  case LibFunc::strcpy_chk:
+    return optimizeStrCpyChk(CI, Builder);
+  case LibFunc::stpncpy_chk:
+  case LibFunc::strncpy_chk:
+    return optimizeStrNCpyChk(CI, Builder);
+  default:
+    break;
+  }
+  return nullptr;
+}
+
+FortifiedLibCallSimplifier::
+FortifiedLibCallSimplifier(const DataLayout *DL, const TargetLibraryInfo *TLI,
+                           bool OnlyLowerUnknownSize)
+  : DL(DL), TLI(TLI), OnlyLowerUnknownSize(OnlyLowerUnknownSize) {
+}
diff --git a/lib/Transforms/Utils/SymbolRewriter.cpp b/lib/Transforms/Utils/SymbolRewriter.cpp
new file mode 100644
index 000000000000..b35a662f17b5
--- /dev/null
+++ b/lib/Transforms/Utils/SymbolRewriter.cpp
@@ -0,0 +1,527 @@
+//===- SymbolRewriter.cpp - Symbol Rewriter ---------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// SymbolRewriter is a LLVM pass which can rewrite symbols transparently within
+// existing code.  It is implemented as a compiler pass and is configured via a
+// YAML configuration file.
+//
+// The YAML configuration file format is as follows:
+//
+// RewriteMapFile := RewriteDescriptors
+// RewriteDescriptors := RewriteDescriptor | RewriteDescriptors
+// RewriteDescriptor := RewriteDescriptorType ':' '{' RewriteDescriptorFields '}'
+// RewriteDescriptorFields := RewriteDescriptorField | RewriteDescriptorFields
+// RewriteDescriptorField := FieldIdentifier ':' FieldValue ','
+// RewriteDescriptorType := Identifier
+// FieldIdentifier := Identifier
+// FieldValue := Identifier
+// Identifier := [0-9a-zA-Z]+
+//
+// Currently, the following descriptor types are supported:
+//
+// - function:          (function rewriting)
+//      + Source        (original name of the function)
+//      + Target        (explicit transformation)
+//      + Transform     (pattern transformation)
+//      + Naked         (boolean, whether the function is undecorated)
+// - global variable:   (external linkage global variable rewriting)
+//      + Source        (original name of externally visible variable)
+//      + Target        (explicit transformation)
+//      + Transform     (pattern transformation)
+// - global alias:      (global alias rewriting)
+//      + Source        (original name of the aliased name)
+//      + Target        (explicit transformation)
+//      + Transform     (pattern transformation)
+//
+// Note that source and exactly one of [Target, Transform] must be provided
+//
+// New rewrite descriptors can be created.  Addding a new rewrite descriptor
+// involves:
+//
+//  a) extended the rewrite descriptor kind enumeration
+//     (<anonymous>::RewriteDescriptor::RewriteDescriptorType)
+//  b) implementing the new descriptor
+//     (c.f. <anonymous>::ExplicitRewriteFunctionDescriptor)
+//  c) extending the rewrite map parser
+//     (<anonymous>::RewriteMapParser::parseEntry)
+//
+//  Specify to rewrite the symbols using the `-rewrite-symbols` option, and
+//  specify the map file to use for the rewriting via the `-rewrite-map-file`
+//  option.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "symbol-rewriter"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/Pass.h"
+#include "llvm/PassManager.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Regex.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/YAMLParser.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Transforms/IPO/PassManagerBuilder.h"
+#include "llvm/Transforms/Utils/SymbolRewriter.h"
+
+using namespace llvm;
+
+static cl::list<std::string> RewriteMapFiles("rewrite-map-file",
+                                             cl::desc("Symbol Rewrite Map"),
+                                             cl::value_desc("filename"));
+
+namespace llvm {
+namespace SymbolRewriter {
+template <RewriteDescriptor::Type DT, typename ValueType,
+          ValueType *(llvm::Module::*Get)(StringRef) const>
+class ExplicitRewriteDescriptor : public RewriteDescriptor {
+public:
+  const std::string Source;
+  const std::string Target;
+
+  ExplicitRewriteDescriptor(StringRef S, StringRef T, const bool Naked)
+      : RewriteDescriptor(DT), Source(Naked ? StringRef("\01" + S.str()) : S),
+        Target(T) {}
+
+  bool performOnModule(Module &M) override;
+
+  static bool classof(const RewriteDescriptor *RD) {
+    return RD->getType() == DT;
+  }
+};
+
+template <RewriteDescriptor::Type DT, typename ValueType,
+          ValueType *(llvm::Module::*Get)(StringRef) const>
+bool ExplicitRewriteDescriptor<DT, ValueType, Get>::performOnModule(Module &M) {
+  bool Changed = false;
+  if (ValueType *S = (M.*Get)(Source)) {
+    if (Value *T = (M.*Get)(Target))
+      S->setValueName(T->getValueName());
+    else
+      S->setName(Target);
+    Changed = true;
+  }
+  return Changed;
+}
+
+template <RewriteDescriptor::Type DT, typename ValueType,
+          ValueType *(llvm::Module::*Get)(StringRef) const,
+          iterator_range<typename iplist<ValueType>::iterator>
+          (llvm::Module::*Iterator)()>
+class PatternRewriteDescriptor : public RewriteDescriptor {
+public:
+  const std::string Pattern;
+  const std::string Transform;
+
+  PatternRewriteDescriptor(StringRef P, StringRef T)
+    : RewriteDescriptor(DT), Pattern(P), Transform(T) { }
+
+  bool performOnModule(Module &M) override;
+
+  static bool classof(const RewriteDescriptor *RD) {
+    return RD->getType() == DT;
+  }
+};
+
+template <RewriteDescriptor::Type DT, typename ValueType,
+          ValueType *(llvm::Module::*Get)(StringRef) const,
+          iterator_range<typename iplist<ValueType>::iterator>
+          (llvm::Module::*Iterator)()>
+bool PatternRewriteDescriptor<DT, ValueType, Get, Iterator>::
+performOnModule(Module &M) {
+  bool Changed = false;
+  for (auto &C : (M.*Iterator)()) {
+    std::string Error;
+
+    std::string Name = Regex(Pattern).sub(Transform, C.getName(), &Error);
+    if (!Error.empty())
+      report_fatal_error("unable to transforn " + C.getName() + " in " +
+                         M.getModuleIdentifier() + ": " + Error);
+
+    if (Value *V = (M.*Get)(Name))
+      C.setValueName(V->getValueName());
+    else
+      C.setName(Name);
+
+    Changed = true;
+  }
+  return Changed;
+}
+
+/// Represents a rewrite for an explicitly named (function) symbol.  Both the
+/// source function name and target function name of the transformation are
+/// explicitly spelt out.
+typedef ExplicitRewriteDescriptor<RewriteDescriptor::Type::Function,
+                                  llvm::Function, &llvm::Module::getFunction>
+    ExplicitRewriteFunctionDescriptor;
+
+/// Represents a rewrite for an explicitly named (global variable) symbol.  Both
+/// the source variable name and target variable name are spelt out.  This
+/// applies only to module level variables.
+typedef ExplicitRewriteDescriptor<RewriteDescriptor::Type::GlobalVariable,
+                                  llvm::GlobalVariable,
+                                  &llvm::Module::getGlobalVariable>
+    ExplicitRewriteGlobalVariableDescriptor;
+
+/// Represents a rewrite for an explicitly named global alias.  Both the source
+/// and target name are explicitly spelt out.
+typedef ExplicitRewriteDescriptor<RewriteDescriptor::Type::NamedAlias,
+                                  llvm::GlobalAlias,
+                                  &llvm::Module::getNamedAlias>
+    ExplicitRewriteNamedAliasDescriptor;
+
+/// Represents a rewrite for a regular expression based pattern for functions.
+/// A pattern for the function name is provided and a transformation for that
+/// pattern to determine the target function name create the rewrite rule.
+typedef PatternRewriteDescriptor<RewriteDescriptor::Type::Function,
+                                 llvm::Function, &llvm::Module::getFunction,
+                                 &llvm::Module::functions>
+    PatternRewriteFunctionDescriptor;
+
+/// Represents a rewrite for a global variable based upon a matching pattern.
+/// Each global variable matching the provided pattern will be transformed as
+/// described in the transformation pattern for the target.  Applies only to
+/// module level variables.
+typedef PatternRewriteDescriptor<RewriteDescriptor::Type::GlobalVariable,
+                                 llvm::GlobalVariable,
+                                 &llvm::Module::getGlobalVariable,
+                                 &llvm::Module::globals>
+    PatternRewriteGlobalVariableDescriptor;
+
+/// PatternRewriteNamedAliasDescriptor - represents a rewrite for global
+/// aliases which match a given pattern.  The provided transformation will be
+/// applied to each of the matching names.
+typedef PatternRewriteDescriptor<RewriteDescriptor::Type::NamedAlias,
+                                 llvm::GlobalAlias,
+                                 &llvm::Module::getNamedAlias,
+                                 &llvm::Module::aliases>
+    PatternRewriteNamedAliasDescriptor;
+
+bool RewriteMapParser::parse(const std::string &MapFile,
+                             RewriteDescriptorList *DL) {
+  ErrorOr<std::unique_ptr<MemoryBuffer>> Mapping =
+      MemoryBuffer::getFile(MapFile);
+
+  if (!Mapping)
+    report_fatal_error("unable to read rewrite map '" + MapFile + "': " +
+                       Mapping.getError().message());
+
+  if (!parse(*Mapping, DL))
+    report_fatal_error("unable to parse rewrite map '" + MapFile + "'");
+
+  return true;
+}
+
+bool RewriteMapParser::parse(std::unique_ptr<MemoryBuffer> &MapFile,
+                             RewriteDescriptorList *DL) {
+  SourceMgr SM;
+  yaml::Stream YS(MapFile->getBuffer(), SM);
+
+  for (auto &Document : YS) {
+    yaml::MappingNode *DescriptorList;
+
+    // ignore empty documents
+    if (isa<yaml::NullNode>(Document.getRoot()))
+      continue;
+
+    DescriptorList = dyn_cast<yaml::MappingNode>(Document.getRoot());
+    if (!DescriptorList) {
+      YS.printError(Document.getRoot(), "DescriptorList node must be a map");
+      return false;
+    }
+
+    for (auto &Descriptor : *DescriptorList)
+      if (!parseEntry(YS, Descriptor, DL))
+        return false;
+  }
+
+  return true;
+}
+
+bool RewriteMapParser::parseEntry(yaml::Stream &YS, yaml::KeyValueNode &Entry,
+                                  RewriteDescriptorList *DL) {
+  yaml::ScalarNode *Key;
+  yaml::MappingNode *Value;
+  SmallString<32> KeyStorage;
+  StringRef RewriteType;
+
+  Key = dyn_cast<yaml::ScalarNode>(Entry.getKey());
+  if (!Key) {
+    YS.printError(Entry.getKey(), "rewrite type must be a scalar");
+    return false;
+  }
+
+  Value = dyn_cast<yaml::MappingNode>(Entry.getValue());
+  if (!Value) {
+    YS.printError(Entry.getValue(), "rewrite descriptor must be a map");
+    return false;
+  }
+
+  RewriteType = Key->getValue(KeyStorage);
+  if (RewriteType.equals("function"))
+    return parseRewriteFunctionDescriptor(YS, Key, Value, DL);
+  else if (RewriteType.equals("global variable"))
+    return parseRewriteGlobalVariableDescriptor(YS, Key, Value, DL);
+  else if (RewriteType.equals("global alias"))
+    return parseRewriteGlobalAliasDescriptor(YS, Key, Value, DL);
+
+  YS.printError(Entry.getKey(), "unknown rewrite type");
+  return false;
+}
+
+bool RewriteMapParser::
+parseRewriteFunctionDescriptor(yaml::Stream &YS, yaml::ScalarNode *K,
+                               yaml::MappingNode *Descriptor,
+                               RewriteDescriptorList *DL) {
+  bool Naked = false;
+  std::string Source;
+  std::string Target;
+  std::string Transform;
+
+  for (auto &Field : *Descriptor) {
+    yaml::ScalarNode *Key;
+    yaml::ScalarNode *Value;
+    SmallString<32> KeyStorage;
+    SmallString<32> ValueStorage;
+    StringRef KeyValue;
+
+    Key = dyn_cast<yaml::ScalarNode>(Field.getKey());
+    if (!Key) {
+      YS.printError(Field.getKey(), "descriptor key must be a scalar");
+      return false;
+    }
+
+    Value = dyn_cast<yaml::ScalarNode>(Field.getValue());
+    if (!Value) {
+      YS.printError(Field.getValue(), "descriptor value must be a scalar");
+      return false;
+    }
+
+    KeyValue = Key->getValue(KeyStorage);
+    if (KeyValue.equals("source")) {
+      std::string Error;
+
+      Source = Value->getValue(ValueStorage);
+      if (!Regex(Source).isValid(Error)) {
+        YS.printError(Field.getKey(), "invalid regex: " + Error);
+        return false;
+      }
+    } else if (KeyValue.equals("target")) {
+      Target = Value->getValue(ValueStorage);
+    } else if (KeyValue.equals("transform")) {
+      Transform = Value->getValue(ValueStorage);
+    } else if (KeyValue.equals("naked")) {
+      std::string Undecorated;
+
+      Undecorated = Value->getValue(ValueStorage);
+      Naked = StringRef(Undecorated).lower() == "true" || Undecorated == "1";
+    } else {
+      YS.printError(Field.getKey(), "unknown key for function");
+      return false;
+    }
+  }
+
+  if (Transform.empty() == Target.empty()) {
+    YS.printError(Descriptor,
+                  "exactly one of transform or target must be specified");
+    return false;
+  }
+
+  // TODO see if there is a more elegant solution to selecting the rewrite
+  // descriptor type
+  if (!Target.empty())
+    DL->push_back(new ExplicitRewriteFunctionDescriptor(Source, Target, Naked));
+  else
+    DL->push_back(new PatternRewriteFunctionDescriptor(Source, Transform));
+
+  return true;
+}
+
+bool RewriteMapParser::
+parseRewriteGlobalVariableDescriptor(yaml::Stream &YS, yaml::ScalarNode *K,
+                                     yaml::MappingNode *Descriptor,
+                                     RewriteDescriptorList *DL) {
+  std::string Source;
+  std::string Target;
+  std::string Transform;
+
+  for (auto &Field : *Descriptor) {
+    yaml::ScalarNode *Key;
+    yaml::ScalarNode *Value;
+    SmallString<32> KeyStorage;
+    SmallString<32> ValueStorage;
+    StringRef KeyValue;
+
+    Key = dyn_cast<yaml::ScalarNode>(Field.getKey());
+    if (!Key) {
+      YS.printError(Field.getKey(), "descriptor Key must be a scalar");
+      return false;
+    }
+
+    Value = dyn_cast<yaml::ScalarNode>(Field.getValue());
+    if (!Value) {
+      YS.printError(Field.getValue(), "descriptor value must be a scalar");
+      return false;
+    }
+
+    KeyValue = Key->getValue(KeyStorage);
+    if (KeyValue.equals("source")) {
+      std::string Error;
+
+      Source = Value->getValue(ValueStorage);
+      if (!Regex(Source).isValid(Error)) {
+        YS.printError(Field.getKey(), "invalid regex: " + Error);
+        return false;
+      }
+    } else if (KeyValue.equals("target")) {
+      Target = Value->getValue(ValueStorage);
+    } else if (KeyValue.equals("transform")) {
+      Transform = Value->getValue(ValueStorage);
+    } else {
+      YS.printError(Field.getKey(), "unknown Key for Global Variable");
+      return false;
+    }
+  }
+
+  if (Transform.empty() == Target.empty()) {
+    YS.printError(Descriptor,
+                  "exactly one of transform or target must be specified");
+    return false;
+  }
+
+  if (!Target.empty())
+    DL->push_back(new ExplicitRewriteGlobalVariableDescriptor(Source, Target,
+                                                              /*Naked*/false));
+  else
+    DL->push_back(new PatternRewriteGlobalVariableDescriptor(Source,
+                                                             Transform));
+
+  return true;
+}
+
+bool RewriteMapParser::
+parseRewriteGlobalAliasDescriptor(yaml::Stream &YS, yaml::ScalarNode *K,
+                                  yaml::MappingNode *Descriptor,
+                                  RewriteDescriptorList *DL) {
+  std::string Source;
+  std::string Target;
+  std::string Transform;
+
+  for (auto &Field : *Descriptor) {
+    yaml::ScalarNode *Key;
+    yaml::ScalarNode *Value;
+    SmallString<32> KeyStorage;
+    SmallString<32> ValueStorage;
+    StringRef KeyValue;
+
+    Key = dyn_cast<yaml::ScalarNode>(Field.getKey());
+    if (!Key) {
+      YS.printError(Field.getKey(), "descriptor key must be a scalar");
+      return false;
+    }
+
+    Value = dyn_cast<yaml::ScalarNode>(Field.getValue());
+    if (!Value) {
+      YS.printError(Field.getValue(), "descriptor value must be a scalar");
+      return false;
+    }
+
+    KeyValue = Key->getValue(KeyStorage);
+    if (KeyValue.equals("source")) {
+      std::string Error;
+
+      Source = Value->getValue(ValueStorage);
+      if (!Regex(Source).isValid(Error)) {
+        YS.printError(Field.getKey(), "invalid regex: " + Error);
+        return false;
+      }
+    } else if (KeyValue.equals("target")) {
+      Target = Value->getValue(ValueStorage);
+    } else if (KeyValue.equals("transform")) {
+      Transform = Value->getValue(ValueStorage);
+    } else {
+      YS.printError(Field.getKey(), "unknown key for Global Alias");
+      return false;
+    }
+  }
+
+  if (Transform.empty() == Target.empty()) {
+    YS.printError(Descriptor,
+                  "exactly one of transform or target must be specified");
+    return false;
+  }
+
+  if (!Target.empty())
+    DL->push_back(new ExplicitRewriteNamedAliasDescriptor(Source, Target,
+                                                          /*Naked*/false));
+  else
+    DL->push_back(new PatternRewriteNamedAliasDescriptor(Source, Transform));
+
+  return true;
+}
+}
+}
+
+namespace {
+class RewriteSymbols : public ModulePass {
+public:
+  static char ID; // Pass identification, replacement for typeid
+
+  RewriteSymbols();
+  RewriteSymbols(SymbolRewriter::RewriteDescriptorList &DL);
+
+  bool runOnModule(Module &M) override;
+
+private:
+  void loadAndParseMapFiles();
+
+  SymbolRewriter::RewriteDescriptorList Descriptors;
+};
+
+char RewriteSymbols::ID = 0;
+
+RewriteSymbols::RewriteSymbols() : ModulePass(ID) {
+  initializeRewriteSymbolsPass(*PassRegistry::getPassRegistry());
+  loadAndParseMapFiles();
+}
+
+RewriteSymbols::RewriteSymbols(SymbolRewriter::RewriteDescriptorList &DL)
+    : ModulePass(ID) {
+  Descriptors.splice(Descriptors.begin(), DL);
+}
+
+bool RewriteSymbols::runOnModule(Module &M) {
+  bool Changed;
+
+  Changed = false;
+  for (auto &Descriptor : Descriptors)
+    Changed |= Descriptor.performOnModule(M);
+
+  return Changed;
+}
+
+void RewriteSymbols::loadAndParseMapFiles() {
+  const std::vector<std::string> MapFiles(RewriteMapFiles);
+  SymbolRewriter::RewriteMapParser parser;
+
+  for (const auto &MapFile : MapFiles)
+    parser.parse(MapFile, &Descriptors);
+}
+}
+
+INITIALIZE_PASS(RewriteSymbols, "rewrite-symbols", "Rewrite Symbols", false,
+                false)
+
+ModulePass *llvm::createRewriteSymbolsPass() { return new RewriteSymbols(); }
+
+ModulePass *
+llvm::createRewriteSymbolsPass(SymbolRewriter::RewriteDescriptorList &DL) {
+  return new RewriteSymbols(DL);
+}
diff --git a/lib/Transforms/Utils/ValueMapper.cpp b/lib/Transforms/Utils/ValueMapper.cpp
index 0f20e6df6c96..477fba42412e 100644
--- a/lib/Transforms/Utils/ValueMapper.cpp
+++ b/lib/Transforms/Utils/ValueMapper.cpp
@@ -40,7 +40,7 @@ Value *llvm::MapValue(const Value *V, ValueToValueMapTy &VM, RemapFlags Flags,
 
   // Global values do not need to be seeded into the VM if they
   // are using the identity mapping.
-  if (isa<GlobalValue>(V) || isa<MDString>(V))
+  if (isa<GlobalValue>(V))
     return VM[V] = const_cast<Value*>(V);
   
   if (const InlineAsm *IA = dyn_cast<InlineAsm>(V)) {
@@ -56,57 +56,24 @@ Value *llvm::MapValue(const Value *V, ValueToValueMapTy &VM, RemapFlags Flags,
     
     return VM[V] = const_cast<Value*>(V);
   }
-  
 
-  if (const MDNode *MD = dyn_cast<MDNode>(V)) {
+  if (const auto *MDV = dyn_cast<MetadataAsValue>(V)) {
+    const Metadata *MD = MDV->getMetadata();
     // If this is a module-level metadata and we know that nothing at the module
     // level is changing, then use an identity mapping.
-    if (!MD->isFunctionLocal() && (Flags & RF_NoModuleLevelChanges))
-      return VM[V] = const_cast<Value*>(V);
-    
-    // Create a dummy node in case we have a metadata cycle.
-    MDNode *Dummy = MDNode::getTemporary(V->getContext(), None);
-    VM[V] = Dummy;
-    
-    // Check all operands to see if any need to be remapped.
-    for (unsigned i = 0, e = MD->getNumOperands(); i != e; ++i) {
-      Value *OP = MD->getOperand(i);
-      if (!OP) continue;
-      Value *Mapped_OP = MapValue(OP, VM, Flags, TypeMapper, Materializer);
-      // Use identity map if Mapped_Op is null and we can ignore missing
-      // entries.
-      if (Mapped_OP == OP ||
-          (Mapped_OP == nullptr && (Flags & RF_IgnoreMissingEntries)))
-        continue;
-
-      // Ok, at least one operand needs remapping.  
-      SmallVector<Value*, 4> Elts;
-      Elts.reserve(MD->getNumOperands());
-      for (i = 0; i != e; ++i) {
-        Value *Op = MD->getOperand(i);
-        if (!Op)
-          Elts.push_back(nullptr);
-        else {
-          Value *Mapped_Op = MapValue(Op, VM, Flags, TypeMapper, Materializer);
-          // Use identity map if Mapped_Op is null and we can ignore missing
-          // entries.
-          if (Mapped_Op == nullptr && (Flags & RF_IgnoreMissingEntries))
-            Mapped_Op = Op;
-          Elts.push_back(Mapped_Op);
-        }
-      }
-      MDNode *NewMD = MDNode::get(V->getContext(), Elts);
-      Dummy->replaceAllUsesWith(NewMD);
-      VM[V] = NewMD;
-      MDNode::deleteTemporary(Dummy);
-      return NewMD;
-    }
+    if (!isa<LocalAsMetadata>(MD) && (Flags & RF_NoModuleLevelChanges))
+      return VM[V] = const_cast<Value *>(V);
 
-    VM[V] = const_cast<Value*>(V);
-    MDNode::deleteTemporary(Dummy);
+    auto *MappedMD = MapMetadata(MD, VM, Flags, TypeMapper, Materializer);
+    if (MD == MappedMD || (!MappedMD && (Flags & RF_IgnoreMissingEntries)))
+      return VM[V] = const_cast<Value *>(V);
 
-    // No operands needed remapping.  Use an identity mapping.
-    return const_cast<Value*>(V);
+    // FIXME: This assert crashes during bootstrap, but I think it should be
+    // correct.  For now, just match behaviour from before the metadata/value
+    // split.
+    //
+    //    assert(MappedMD && "Referenced metadata value not in value map");
+    return VM[V] = MetadataAsValue::get(V->getContext(), MappedMD);
   }
 
   // Okay, this either must be a constant (which may or may not be mappable) or
@@ -177,6 +144,229 @@ Value *llvm::MapValue(const Value *V, ValueToValueMapTy &VM, RemapFlags Flags,
   return VM[V] = ConstantPointerNull::get(cast<PointerType>(NewTy));
 }
 
+static Metadata *mapToMetadata(ValueToValueMapTy &VM, const Metadata *Key,
+                     Metadata *Val) {
+  VM.MD()[Key].reset(Val);
+  return Val;
+}
+
+static Metadata *mapToSelf(ValueToValueMapTy &VM, const Metadata *MD) {
+  return mapToMetadata(VM, MD, const_cast<Metadata *>(MD));
+}
+
+static Metadata *MapMetadataImpl(const Metadata *MD, ValueToValueMapTy &VM,
+                                 RemapFlags Flags,
+                                 ValueMapTypeRemapper *TypeMapper,
+                                 ValueMaterializer *Materializer);
+
+static Metadata *mapMetadataOp(Metadata *Op, ValueToValueMapTy &VM,
+                                 RemapFlags Flags,
+                                 ValueMapTypeRemapper *TypeMapper,
+                                 ValueMaterializer *Materializer) {
+  if (!Op)
+    return nullptr;
+  if (Metadata *MappedOp =
+          MapMetadataImpl(Op, VM, Flags, TypeMapper, Materializer))
+    return MappedOp;
+  // Use identity map if MappedOp is null and we can ignore missing entries.
+  if (Flags & RF_IgnoreMissingEntries)
+    return Op;
+
+  // FIXME: This assert crashes during bootstrap, but I think it should be
+  // correct.  For now, just match behaviour from before the metadata/value
+  // split.
+  //
+  //    llvm_unreachable("Referenced metadata not in value map!");
+  return nullptr;
+}
+
+static Metadata *cloneMDTuple(const MDTuple *Node, ValueToValueMapTy &VM,
+                              RemapFlags Flags,
+                              ValueMapTypeRemapper *TypeMapper,
+                              ValueMaterializer *Materializer,
+                              bool IsDistinct) {
+  // Distinct MDTuples have their own code path.
+  assert(!IsDistinct && "Unexpected distinct tuple");
+  (void)IsDistinct;
+
+  SmallVector<Metadata *, 4> Elts;
+  Elts.reserve(Node->getNumOperands());
+  for (unsigned I = 0, E = Node->getNumOperands(); I != E; ++I)
+    Elts.push_back(mapMetadataOp(Node->getOperand(I), VM, Flags, TypeMapper,
+                                 Materializer));
+
+  return MDTuple::get(Node->getContext(), Elts);
+}
+
+static Metadata *cloneMDLocation(const MDLocation *Node, ValueToValueMapTy &VM,
+                                 RemapFlags Flags,
+                                 ValueMapTypeRemapper *TypeMapper,
+                                 ValueMaterializer *Materializer,
+                                 bool IsDistinct) {
+  return (IsDistinct ? MDLocation::getDistinct : MDLocation::get)(
+      Node->getContext(), Node->getLine(), Node->getColumn(),
+      mapMetadataOp(Node->getScope(), VM, Flags, TypeMapper, Materializer),
+      mapMetadataOp(Node->getInlinedAt(), VM, Flags, TypeMapper, Materializer));
+}
+
+static Metadata *cloneMDNode(const UniquableMDNode *Node, ValueToValueMapTy &VM,
+                             RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
+                             ValueMaterializer *Materializer, bool IsDistinct) {
+  switch (Node->getMetadataID()) {
+  default:
+    llvm_unreachable("Invalid UniquableMDNode subclass");
+#define HANDLE_UNIQUABLE_LEAF(CLASS)                                           \
+  case Metadata::CLASS##Kind:                                                  \
+    return clone##CLASS(cast<CLASS>(Node), VM, Flags, TypeMapper,              \
+                        Materializer, IsDistinct);
+#include "llvm/IR/Metadata.def"
+  }
+}
+
+/// \brief Map a distinct MDNode.
+///
+/// Distinct nodes are not uniqued, so they must always recreated.
+static Metadata *mapDistinctNode(const UniquableMDNode *Node,
+                                 ValueToValueMapTy &VM, RemapFlags Flags,
+                                 ValueMapTypeRemapper *TypeMapper,
+                                 ValueMaterializer *Materializer) {
+  assert(Node->isDistinct() && "Expected distinct node");
+
+  // Optimization for MDTuples.
+  if (isa<MDTuple>(Node)) {
+    // Create the node first so it's available for cyclical references.
+    SmallVector<Metadata *, 4> EmptyOps(Node->getNumOperands());
+    MDTuple *NewMD = MDTuple::getDistinct(Node->getContext(), EmptyOps);
+    mapToMetadata(VM, Node, NewMD);
+
+    // Fix the operands.
+    for (unsigned I = 0, E = Node->getNumOperands(); I != E; ++I)
+      NewMD->replaceOperandWith(I, mapMetadataOp(Node->getOperand(I), VM, Flags,
+                                                 TypeMapper, Materializer));
+
+    return NewMD;
+  }
+
+  // In general we need a dummy node, since whether the operands are null can
+  // affect the size of the node.
+  std::unique_ptr<MDNodeFwdDecl> Dummy(
+      MDNode::getTemporary(Node->getContext(), None));
+  mapToMetadata(VM, Node, Dummy.get());
+  Metadata *NewMD = cloneMDNode(Node, VM, Flags, TypeMapper, Materializer,
+                                /* IsDistinct */ true);
+  Dummy->replaceAllUsesWith(NewMD);
+  return mapToMetadata(VM, Node, NewMD);
+}
+
+/// \brief Check whether a uniqued node needs to be remapped.
+///
+/// Check whether a uniqued node needs to be remapped (due to any operands
+/// changing).
+static bool shouldRemapUniquedNode(const UniquableMDNode *Node,
+                                   ValueToValueMapTy &VM, RemapFlags Flags,
+                                   ValueMapTypeRemapper *TypeMapper,
+                                   ValueMaterializer *Materializer) {
+  // Check all operands to see if any need to be remapped.
+  for (unsigned I = 0, E = Node->getNumOperands(); I != E; ++I) {
+    Metadata *Op = Node->getOperand(I);
+    if (Op != mapMetadataOp(Op, VM, Flags, TypeMapper, Materializer))
+      return true;
+  }
+  return false;
+}
+
+/// \brief Map a uniqued MDNode.
+///
+/// Uniqued nodes may not need to be recreated (they may map to themselves).
+static Metadata *mapUniquedNode(const UniquableMDNode *Node,
+                                 ValueToValueMapTy &VM, RemapFlags Flags,
+                                 ValueMapTypeRemapper *TypeMapper,
+                                 ValueMaterializer *Materializer) {
+  assert(!Node->isDistinct() && "Expected uniqued node");
+
+  // Create a dummy node in case we have a metadata cycle.
+  MDNodeFwdDecl *Dummy = MDNode::getTemporary(Node->getContext(), None);
+  mapToMetadata(VM, Node, Dummy);
+
+  // Check all operands to see if any need to be remapped.
+  if (!shouldRemapUniquedNode(Node, VM, Flags, TypeMapper, Materializer)) {
+    // Use an identity mapping.
+    mapToSelf(VM, Node);
+    MDNode::deleteTemporary(Dummy);
+    return const_cast<Metadata *>(static_cast<const Metadata *>(Node));
+  }
+
+  // At least one operand needs remapping.
+  Metadata *NewMD = cloneMDNode(Node, VM, Flags, TypeMapper, Materializer,
+                                /* IsDistinct */ false);
+  Dummy->replaceAllUsesWith(NewMD);
+  MDNode::deleteTemporary(Dummy);
+  return mapToMetadata(VM, Node, NewMD);
+}
+
+static Metadata *MapMetadataImpl(const Metadata *MD, ValueToValueMapTy &VM,
+                                 RemapFlags Flags,
+                                 ValueMapTypeRemapper *TypeMapper,
+                                 ValueMaterializer *Materializer) {
+  // If the value already exists in the map, use it.
+  if (Metadata *NewMD = VM.MD().lookup(MD).get())
+    return NewMD;
+
+  if (isa<MDString>(MD))
+    return mapToSelf(VM, MD);
+
+  if (isa<ConstantAsMetadata>(MD))
+    if ((Flags & RF_NoModuleLevelChanges))
+      return mapToSelf(VM, MD);
+
+  if (const auto *VMD = dyn_cast<ValueAsMetadata>(MD)) {
+    Value *MappedV =
+        MapValue(VMD->getValue(), VM, Flags, TypeMapper, Materializer);
+    if (VMD->getValue() == MappedV ||
+        (!MappedV && (Flags & RF_IgnoreMissingEntries)))
+      return mapToSelf(VM, MD);
+
+    // FIXME: This assert crashes during bootstrap, but I think it should be
+    // correct.  For now, just match behaviour from before the metadata/value
+    // split.
+    //
+    //    assert(MappedV && "Referenced metadata not in value map!");
+    if (MappedV)
+      return mapToMetadata(VM, MD, ValueAsMetadata::get(MappedV));
+    return nullptr;
+  }
+
+  const UniquableMDNode *Node = cast<UniquableMDNode>(MD);
+  assert(Node->isResolved() && "Unexpected unresolved node");
+
+  // If this is a module-level metadata and we know that nothing at the
+  // module level is changing, then use an identity mapping.
+  if (Flags & RF_NoModuleLevelChanges)
+    return mapToSelf(VM, MD);
+
+  if (Node->isDistinct())
+    return mapDistinctNode(Node, VM, Flags, TypeMapper, Materializer);
+
+  return mapUniquedNode(Node, VM, Flags, TypeMapper, Materializer);
+}
+
+Metadata *llvm::MapMetadata(const Metadata *MD, ValueToValueMapTy &VM,
+                            RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
+                            ValueMaterializer *Materializer) {
+  Metadata *NewMD = MapMetadataImpl(MD, VM, Flags, TypeMapper, Materializer);
+  if (NewMD && NewMD != MD)
+    if (auto *N = dyn_cast<UniquableMDNode>(NewMD))
+      N->resolveCycles();
+  return NewMD;
+}
+
+MDNode *llvm::MapMetadata(const MDNode *MD, ValueToValueMapTy &VM,
+                          RemapFlags Flags, ValueMapTypeRemapper *TypeMapper,
+                          ValueMaterializer *Materializer) {
+  return cast<MDNode>(MapMetadata(static_cast<const Metadata *>(MD), VM, Flags,
+                                  TypeMapper, Materializer));
+}
+
 /// RemapInstruction - Convert the instruction operands from referencing the
 /// current values into those specified by VMap.
 ///
@@ -210,10 +400,12 @@ void llvm::RemapInstruction(Instruction *I, ValueToValueMapTy &VMap,
   // Remap attached metadata.
   SmallVector<std::pair<unsigned, MDNode *>, 4> MDs;
   I->getAllMetadata(MDs);
-  for (SmallVectorImpl<std::pair<unsigned, MDNode *> >::iterator
-       MI = MDs.begin(), ME = MDs.end(); MI != ME; ++MI) {
+  for (SmallVectorImpl<std::pair<unsigned, MDNode *>>::iterator
+           MI = MDs.begin(),
+           ME = MDs.end();
+       MI != ME; ++MI) {
     MDNode *Old = MI->second;
-    MDNode *New = MapValue(Old, VMap, Flags, TypeMapper, Materializer);
+    MDNode *New = MapMetadata(Old, VMap, Flags, TypeMapper, Materializer);
     if (New != Old)
       I->setMetadata(MI->first, New);
   }