1 files changed, 170 insertions, 137 deletions

diff --git a/contrib/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/contrib/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index 7c195788e416..c87b5c16ffce 100644
--- a/contrib/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/contrib/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -19,7 +19,6 @@
 #include "llvm/ADT/SetOperations.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringRef.h"
@@ -28,6 +27,7 @@
 #include "llvm/Analysis/EHPersonalities.h"
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
+#include "llvm/Transforms/Utils/Local.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/BasicBlock.h"
@@ -66,7 +66,6 @@
 #include "llvm/Support/MathExtras.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 <cassert>
@@ -688,9 +687,7 @@ Value *SimplifyCFGOpt::isValueEqualityComparison(TerminatorInst *TI) {
   if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) {
     // Do not permit merging of large switch instructions into their
     // predecessors unless there is only one predecessor.
-    if (SI->getNumSuccessors() * std::distance(pred_begin(SI->getParent()),
-                                               pred_end(SI->getParent())) <=
-        128)
+    if (SI->getNumSuccessors() * pred_size(SI->getParent()) <= 128)
       CV = SI->getCondition();
   } else if (BranchInst *BI = dyn_cast<BranchInst>(TI))
     if (BI->isConditional() && BI->getCondition()->hasOneUse())
@@ -847,9 +844,9 @@ bool SimplifyCFGOpt::SimplifyEqualityComparisonWithOnlyPredecessor(
       // Remove PHI node entries for the dead edge.
       ThisCases[0].Dest->removePredecessor(TI->getParent());
 
-      DEBUG(dbgs() << "Threading pred instr: " << *Pred->getTerminator()
-                   << "Through successor TI: " << *TI << "Leaving: " << *NI
-                   << "\n");
+      LLVM_DEBUG(dbgs() << "Threading pred instr: " << *Pred->getTerminator()
+                        << "Through successor TI: " << *TI << "Leaving: " << *NI
+                        << "\n");
 
       EraseTerminatorInstAndDCECond(TI);
       return true;
@@ -861,8 +858,8 @@ bool SimplifyCFGOpt::SimplifyEqualityComparisonWithOnlyPredecessor(
     for (unsigned i = 0, e = PredCases.size(); i != e; ++i)
       DeadCases.insert(PredCases[i].Value);
 
-    DEBUG(dbgs() << "Threading pred instr: " << *Pred->getTerminator()
-                 << "Through successor TI: " << *TI);
+    LLVM_DEBUG(dbgs() << "Threading pred instr: " << *Pred->getTerminator()
+                      << "Through successor TI: " << *TI);
 
     // Collect branch weights into a vector.
     SmallVector<uint32_t, 8> Weights;
@@ -888,7 +885,7 @@ bool SimplifyCFGOpt::SimplifyEqualityComparisonWithOnlyPredecessor(
     if (HasWeight && Weights.size() >= 2)
       setBranchWeights(SI, Weights);
 
-    DEBUG(dbgs() << "Leaving: " << *TI << "\n");
+    LLVM_DEBUG(dbgs() << "Leaving: " << *TI << "\n");
     return true;
   }
 
@@ -929,9 +926,9 @@ bool SimplifyCFGOpt::SimplifyEqualityComparisonWithOnlyPredecessor(
   Instruction *NI = Builder.CreateBr(TheRealDest);
   (void)NI;
 
-  DEBUG(dbgs() << "Threading pred instr: " << *Pred->getTerminator()
-               << "Through successor TI: " << *TI << "Leaving: " << *NI
-               << "\n");
+  LLVM_DEBUG(dbgs() << "Threading pred instr: " << *Pred->getTerminator()
+                    << "Through successor TI: " << *TI << "Leaving: " << *NI
+                    << "\n");
 
   EraseTerminatorInstAndDCECond(TI);
   return true;
@@ -1290,31 +1287,44 @@ static bool HoistThenElseCodeToIf(BranchInst *BI,
     if (!TTI.isProfitableToHoist(I1) || !TTI.isProfitableToHoist(I2))
       return Changed;
 
-    // For a normal instruction, we just move one to right before the branch,
-    // then replace all uses of the other with the first.  Finally, we remove
-    // the now redundant second instruction.
-    BIParent->getInstList().splice(BI->getIterator(), BB1->getInstList(), I1);
-    if (!I2->use_empty())
-      I2->replaceAllUsesWith(I1);
-    I1->andIRFlags(I2);
-    unsigned KnownIDs[] = {LLVMContext::MD_tbaa,
-                           LLVMContext::MD_range,
-                           LLVMContext::MD_fpmath,
-                           LLVMContext::MD_invariant_load,
-                           LLVMContext::MD_nonnull,
-                           LLVMContext::MD_invariant_group,
-                           LLVMContext::MD_align,
-                           LLVMContext::MD_dereferenceable,
-                           LLVMContext::MD_dereferenceable_or_null,
-                           LLVMContext::MD_mem_parallel_loop_access};
-    combineMetadata(I1, I2, KnownIDs);
-
-    // I1 and I2 are being combined into a single instruction.  Its debug
-    // location is the merged locations of the original instructions.
-    I1->applyMergedLocation(I1->getDebugLoc(), I2->getDebugLoc());
-
-    I2->eraseFromParent();
-    Changed = true;
+    if (isa<DbgInfoIntrinsic>(I1) || isa<DbgInfoIntrinsic>(I2)) {
+      assert (isa<DbgInfoIntrinsic>(I1) && isa<DbgInfoIntrinsic>(I2));
+      // The debug location is an integral part of a debug info intrinsic
+      // and can't be separated from it or replaced.  Instead of attempting
+      // to merge locations, simply hoist both copies of the intrinsic.
+      BIParent->getInstList().splice(BI->getIterator(),
+                                     BB1->getInstList(), I1);
+      BIParent->getInstList().splice(BI->getIterator(),
+                                     BB2->getInstList(), I2);
+      Changed = true;
+    } else {
+      // For a normal instruction, we just move one to right before the branch,
+      // then replace all uses of the other with the first.  Finally, we remove
+      // the now redundant second instruction.
+      BIParent->getInstList().splice(BI->getIterator(),
+                                     BB1->getInstList(), I1);
+      if (!I2->use_empty())
+        I2->replaceAllUsesWith(I1);
+      I1->andIRFlags(I2);
+      unsigned KnownIDs[] = {LLVMContext::MD_tbaa,
+                             LLVMContext::MD_range,
+                             LLVMContext::MD_fpmath,
+                             LLVMContext::MD_invariant_load,
+                             LLVMContext::MD_nonnull,
+                             LLVMContext::MD_invariant_group,
+                             LLVMContext::MD_align,
+                             LLVMContext::MD_dereferenceable,
+                             LLVMContext::MD_dereferenceable_or_null,
+                             LLVMContext::MD_mem_parallel_loop_access};
+      combineMetadata(I1, I2, KnownIDs);
+
+      // I1 and I2 are being combined into a single instruction.  Its debug
+      // location is the merged locations of the original instructions.
+      I1->applyMergedLocation(I1->getDebugLoc(), I2->getDebugLoc());
+
+      I2->eraseFromParent();
+      Changed = true;
+    }
 
     I1 = &*BB1_Itr++;
     I2 = &*BB2_Itr++;
@@ -1728,7 +1738,8 @@ static bool SinkCommonCodeFromPredecessors(BasicBlock *BB) {
   LockstepReverseIterator LRI(UnconditionalPreds);
   while (LRI.isValid() &&
          canSinkInstructions(*LRI, PHIOperands)) {
-    DEBUG(dbgs() << "SINK: instruction can be sunk: " << *(*LRI)[0] << "\n");
+    LLVM_DEBUG(dbgs() << "SINK: instruction can be sunk: " << *(*LRI)[0]
+                      << "\n");
     InstructionsToSink.insert((*LRI).begin(), (*LRI).end());
     ++ScanIdx;
     --LRI;
@@ -1740,7 +1751,7 @@ static bool SinkCommonCodeFromPredecessors(BasicBlock *BB) {
       for (auto *V : PHIOperands[I])
         if (InstructionsToSink.count(V) == 0)
           ++NumPHIdValues;
-    DEBUG(dbgs() << "SINK: #phid values: " << NumPHIdValues << "\n");
+    LLVM_DEBUG(dbgs() << "SINK: #phid values: " << NumPHIdValues << "\n");
     unsigned NumPHIInsts = NumPHIdValues / UnconditionalPreds.size();
     if ((NumPHIdValues % UnconditionalPreds.size()) != 0)
         NumPHIInsts++;
@@ -1768,7 +1779,7 @@ static bool SinkCommonCodeFromPredecessors(BasicBlock *BB) {
     if (!Profitable)
       return false;
 
-    DEBUG(dbgs() << "SINK: Splitting edge\n");
+    LLVM_DEBUG(dbgs() << "SINK: Splitting edge\n");
     // We have a conditional edge and we're going to sink some instructions.
     // Insert a new block postdominating all blocks we're going to sink from.
     if (!SplitBlockPredecessors(BB, UnconditionalPreds, ".sink.split"))
@@ -1790,16 +1801,17 @@ static bool SinkCommonCodeFromPredecessors(BasicBlock *BB) {
   // and never actually sink it which means we produce more PHIs than intended.
   // This is unlikely in practice though.
   for (unsigned SinkIdx = 0; SinkIdx != ScanIdx; ++SinkIdx) {
-    DEBUG(dbgs() << "SINK: Sink: "
-                 << *UnconditionalPreds[0]->getTerminator()->getPrevNode()
-                 << "\n");
+    LLVM_DEBUG(dbgs() << "SINK: Sink: "
+                      << *UnconditionalPreds[0]->getTerminator()->getPrevNode()
+                      << "\n");
 
     // Because we've sunk every instruction in turn, the current instruction to
     // sink is always at index 0.
     LRI.reset();
     if (!ProfitableToSinkInstruction(LRI)) {
       // Too many PHIs would be created.
-      DEBUG(dbgs() << "SINK: stopping here, too many PHIs would be created!\n");
+      LLVM_DEBUG(
+          dbgs() << "SINK: stopping here, too many PHIs would be created!\n");
       break;
     }
 
@@ -1811,7 +1823,7 @@ static bool SinkCommonCodeFromPredecessors(BasicBlock *BB) {
   return Changed;
 }
 
-/// \brief Determine if we can hoist sink a sole store instruction out of a
+/// Determine if we can hoist sink a sole store instruction out of a
 /// conditional block.
 ///
 /// We are looking for code like the following:
@@ -1851,12 +1863,9 @@ static Value *isSafeToSpeculateStore(Instruction *I, BasicBlock *BrBB,
 
   // Look for a store to the same pointer in BrBB.
   unsigned MaxNumInstToLookAt = 9;
-  for (Instruction &CurI : reverse(*BrBB)) {
+  for (Instruction &CurI : reverse(BrBB->instructionsWithoutDebug())) {
     if (!MaxNumInstToLookAt)
       break;
-    // Skip debug info.
-    if (isa<DbgInfoIntrinsic>(CurI))
-      continue;
     --MaxNumInstToLookAt;
 
     // Could be calling an instruction that affects memory like free().
@@ -1875,7 +1884,7 @@ static Value *isSafeToSpeculateStore(Instruction *I, BasicBlock *BrBB,
   return nullptr;
 }
 
-/// \brief Speculate a conditional basic block flattening the CFG.
+/// Speculate a conditional basic block flattening the CFG.
 ///
 /// Note that this is a very risky transform currently. Speculating
 /// instructions like this is most often not desirable. Instead, there is an MI
@@ -2045,7 +2054,7 @@ static bool SpeculativelyExecuteBB(BranchInst *BI, BasicBlock *ThenBB,
     return false;
 
   // If we get here, we can hoist the instruction and if-convert.
-  DEBUG(dbgs() << "SPECULATIVELY EXECUTING BB" << *ThenBB << "\n";);
+  LLVM_DEBUG(dbgs() << "SPECULATIVELY EXECUTING BB" << *ThenBB << "\n";);
 
   // Insert a select of the value of the speculated store.
   if (SpeculatedStoreValue) {
@@ -2106,19 +2115,16 @@ static bool SpeculativelyExecuteBB(BranchInst *BI, BasicBlock *ThenBB,
 
 /// Return true if we can thread a branch across this block.
 static bool BlockIsSimpleEnoughToThreadThrough(BasicBlock *BB) {
-  BranchInst *BI = cast<BranchInst>(BB->getTerminator());
   unsigned Size = 0;
 
-  for (BasicBlock::iterator BBI = BB->begin(); &*BBI != BI; ++BBI) {
-    if (isa<DbgInfoIntrinsic>(BBI))
-      continue;
+  for (Instruction &I : BB->instructionsWithoutDebug()) {
     if (Size > 10)
       return false; // Don't clone large BB's.
     ++Size;
 
     // We can only support instructions that do not define values that are
     // live outside of the current basic block.
-    for (User *U : BBI->users()) {
+    for (User *U : I.users()) {
       Instruction *UI = cast<Instruction>(U);
       if (UI->getParent() != BB || isa<PHINode>(UI))
         return false;
@@ -2260,6 +2266,10 @@ static bool FoldTwoEntryPHINode(PHINode *PN, const TargetTransformInfo &TTI,
   // dependence information for this check, but simplifycfg can't keep it up
   // to date, and this catches most of the cases we care about anyway.
   BasicBlock *BB = PN->getParent();
+  const Function *Fn = BB->getParent();
+  if (Fn && Fn->hasFnAttribute(Attribute::OptForFuzzing))
+    return false;
+
   BasicBlock *IfTrue, *IfFalse;
   Value *IfCond = GetIfCondition(BB, IfTrue, IfFalse);
   if (!IfCond ||
@@ -2350,8 +2360,9 @@ static bool FoldTwoEntryPHINode(PHINode *PN, const TargetTransformInfo &TTI,
       }
   }
 
-  DEBUG(dbgs() << "FOUND IF CONDITION!  " << *IfCond << "  T: "
-               << IfTrue->getName() << "  F: " << IfFalse->getName() << "\n");
+  LLVM_DEBUG(dbgs() << "FOUND IF CONDITION!  " << *IfCond
+                    << "  T: " << IfTrue->getName()
+                    << "  F: " << IfFalse->getName() << "\n");
 
   // If we can still promote the PHI nodes after this gauntlet of tests,
   // do all of the PHI's now.
@@ -2475,9 +2486,9 @@ static bool SimplifyCondBranchToTwoReturns(BranchInst *BI,
 
   (void)RI;
 
-  DEBUG(dbgs() << "\nCHANGING BRANCH TO TWO RETURNS INTO SELECT:"
-               << "\n  " << *BI << "NewRet = " << *RI
-               << "TRUEBLOCK: " << *TrueSucc << "FALSEBLOCK: " << *FalseSucc);
+  LLVM_DEBUG(dbgs() << "\nCHANGING BRANCH TO TWO RETURNS INTO SELECT:"
+                    << "\n  " << *BI << "NewRet = " << *RI << "TRUEBLOCK: "
+                    << *TrueSucc << "FALSEBLOCK: " << *FalseSucc);
 
   EraseTerminatorInstAndDCECond(BI);
 
@@ -2486,7 +2497,7 @@ static bool SimplifyCondBranchToTwoReturns(BranchInst *BI,
 
 /// Return true if the given instruction is available
 /// in its predecessor block. If yes, the instruction will be removed.
-static bool checkCSEInPredecessor(Instruction *Inst, BasicBlock *PB) {
+static bool tryCSEWithPredecessor(Instruction *Inst, BasicBlock *PB) {
   if (!isa<BinaryOperator>(Inst) && !isa<CmpInst>(Inst))
     return false;
   for (Instruction &I : *PB) {
@@ -2543,14 +2554,16 @@ bool llvm::FoldBranchToCommonDest(BranchInst *BI, unsigned BonusInstThreshold) {
         if (PBI->isConditional() &&
             (BI->getSuccessor(0) == PBI->getSuccessor(0) ||
              BI->getSuccessor(0) == PBI->getSuccessor(1))) {
-          for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E;) {
+          for (auto I = BB->instructionsWithoutDebug().begin(),
+                    E = BB->instructionsWithoutDebug().end();
+               I != E;) {
             Instruction *Curr = &*I++;
             if (isa<CmpInst>(Curr)) {
               Cond = Curr;
               break;
             }
             // Quit if we can't remove this instruction.
-            if (!checkCSEInPredecessor(Curr, PB))
+            if (!tryCSEWithPredecessor(Curr, PB))
               return false;
           }
         }
@@ -2650,7 +2663,7 @@ bool llvm::FoldBranchToCommonDest(BranchInst *BI, unsigned BonusInstThreshold) {
         continue;
     }
 
-    DEBUG(dbgs() << "FOLDING BRANCH TO COMMON DEST:\n" << *PBI << *BB);
+    LLVM_DEBUG(dbgs() << "FOLDING BRANCH TO COMMON DEST:\n" << *PBI << *BB);
     IRBuilder<> Builder(PBI);
 
     // If we need to invert the condition in the pred block to match, do so now.
@@ -2860,7 +2873,7 @@ static Value *ensureValueAvailableInSuccessor(Value *V, BasicBlock *BB,
       if (!AlternativeV)
         break;
 
-      assert(std::distance(pred_begin(Succ), pred_end(Succ)) == 2);
+      assert(pred_size(Succ) == 2);
       auto PredI = pred_begin(Succ);
       BasicBlock *OtherPredBB = *PredI == BB ? *++PredI : *PredI;
       if (PHI->getIncomingValueForBlock(OtherPredBB) == AlternativeV)
@@ -2903,14 +2916,13 @@ static bool mergeConditionalStoreToAddress(BasicBlock *PTB, BasicBlock *PFB,
     // instructions inside are all cheap (arithmetic/GEPs), it's worthwhile to
     // thread this store.
     unsigned N = 0;
-    for (auto &I : *BB) {
+    for (auto &I : BB->instructionsWithoutDebug()) {
       // Cheap instructions viable for folding.
       if (isa<BinaryOperator>(I) || isa<GetElementPtrInst>(I) ||
           isa<StoreInst>(I))
         ++N;
       // Free instructions.
-      else if (isa<TerminatorInst>(I) || isa<DbgInfoIntrinsic>(I) ||
-               IsaBitcastOfPointerType(I))
+      else if (isa<TerminatorInst>(I) || IsaBitcastOfPointerType(I))
         continue;
       else
         return false;
@@ -2965,6 +2977,21 @@ static bool mergeConditionalStoreToAddress(BasicBlock *PTB, BasicBlock *PFB,
     if (&*I != PStore && I->mayReadOrWriteMemory())
       return false;
 
+  // If PostBB has more than two predecessors, we need to split it so we can
+  // sink the store.
+  if (std::next(pred_begin(PostBB), 2) != pred_end(PostBB)) {
+    // We know that QFB's only successor is PostBB. And QFB has a single
+    // predecessor. If QTB exists, then its only successor is also PostBB.
+    // If QTB does not exist, then QFB's only predecessor has a conditional
+    // branch to QFB and PostBB.
+    BasicBlock *TruePred = QTB ? QTB : QFB->getSinglePredecessor();
+    BasicBlock *NewBB = SplitBlockPredecessors(PostBB, { QFB, TruePred},
+                                               "condstore.split");
+    if (!NewBB)
+      return false;
+    PostBB = NewBB;
+  }
+
   // OK, we're going to sink the stores to PostBB. The store has to be
   // conditional though, so first create the predicate.
   Value *PCond = cast<BranchInst>(PFB->getSinglePredecessor()->getTerminator())
@@ -3100,7 +3127,7 @@ static bool mergeConditionalStores(BranchInst *PBI, BranchInst *QBI,
   if ((PTB && !HasOnePredAndOneSucc(PTB, PBI->getParent(), QBI->getParent())) ||
       (QTB && !HasOnePredAndOneSucc(QTB, QBI->getParent(), PostBB)))
     return false;
-  if (!PostBB->hasNUses(2) || !QBI->getParent()->hasNUses(2))
+  if (!QBI->getParent()->hasNUses(2))
     return false;
 
   // OK, this is a sequence of two diamonds or triangles.
@@ -3200,11 +3227,9 @@ static bool SimplifyCondBranchToCondBranch(BranchInst *PBI, BranchInst *BI,
   // If this is a conditional branch in an empty block, and if any
   // predecessors are a conditional branch to one of our destinations,
   // fold the conditions into logical ops and one cond br.
-  BasicBlock::iterator BBI = BB->begin();
+
   // Ignore dbg intrinsics.
-  while (isa<DbgInfoIntrinsic>(BBI))
-    ++BBI;
-  if (&*BBI != BI)
+  if (&*BB->instructionsWithoutDebug().begin() != BI)
     return false;
 
   int PBIOp, BIOp;
@@ -3261,8 +3286,8 @@ static bool SimplifyCondBranchToCondBranch(BranchInst *PBI, BranchInst *BI,
   // Finally, if everything is ok, fold the branches to logical ops.
   BasicBlock *OtherDest = BI->getSuccessor(BIOp ^ 1);
 
-  DEBUG(dbgs() << "FOLDING BRs:" << *PBI->getParent()
-               << "AND: " << *BI->getParent());
+  LLVM_DEBUG(dbgs() << "FOLDING BRs:" << *PBI->getParent()
+                    << "AND: " << *BI->getParent());
 
   // If OtherDest *is* BB, then BB is a basic block with a single conditional
   // branch in it, where one edge (OtherDest) goes back to itself but the other
@@ -3280,7 +3305,7 @@ static bool SimplifyCondBranchToCondBranch(BranchInst *PBI, BranchInst *BI,
     OtherDest = InfLoopBlock;
   }
 
-  DEBUG(dbgs() << *PBI->getParent()->getParent());
+  LLVM_DEBUG(dbgs() << *PBI->getParent()->getParent());
 
   // BI may have other predecessors.  Because of this, we leave
   // it alone, but modify PBI.
@@ -3364,8 +3389,8 @@ static bool SimplifyCondBranchToCondBranch(BranchInst *PBI, BranchInst *BI,
     }
   }
 
-  DEBUG(dbgs() << "INTO: " << *PBI->getParent());
-  DEBUG(dbgs() << *PBI->getParent()->getParent());
+  LLVM_DEBUG(dbgs() << "INTO: " << *PBI->getParent());
+  LLVM_DEBUG(dbgs() << *PBI->getParent()->getParent());
 
   // This basic block is probably dead.  We know it has at least
   // one fewer predecessor.
@@ -3665,9 +3690,9 @@ static bool SimplifyBranchOnICmpChain(BranchInst *BI, IRBuilder<> &Builder,
 
   BasicBlock *BB = BI->getParent();
 
-  DEBUG(dbgs() << "Converting 'icmp' chain with " << Values.size()
-               << " cases into SWITCH.  BB is:\n"
-               << *BB);
+  LLVM_DEBUG(dbgs() << "Converting 'icmp' chain with " << Values.size()
+                    << " cases into SWITCH.  BB is:\n"
+                    << *BB);
 
   // If there are any extra values that couldn't be folded into the switch
   // then we evaluate them with an explicit branch first.  Split the block
@@ -3690,8 +3715,8 @@ static bool SimplifyBranchOnICmpChain(BranchInst *BI, IRBuilder<> &Builder,
     // for the edge we just added.
     AddPredecessorToBlock(EdgeBB, BB, NewBB);
 
-    DEBUG(dbgs() << "  ** 'icmp' chain unhandled condition: " << *ExtraCase
-                 << "\nEXTRABB = " << *BB);
+    LLVM_DEBUG(dbgs() << "  ** 'icmp' chain unhandled condition: " << *ExtraCase
+                      << "\nEXTRABB = " << *BB);
     BB = NewBB;
   }
 
@@ -3722,7 +3747,7 @@ static bool SimplifyBranchOnICmpChain(BranchInst *BI, IRBuilder<> &Builder,
   // Erase the old branch instruction.
   EraseTerminatorInstAndDCECond(BI);
 
-  DEBUG(dbgs() << "  ** 'icmp' chain result is:\n" << *BB << '\n');
+  LLVM_DEBUG(dbgs() << "  ** 'icmp' chain result is:\n" << *BB << '\n');
   return true;
 }
 
@@ -3873,6 +3898,7 @@ static bool removeEmptyCleanup(CleanupReturnInst *RI) {
     switch (IntrinsicID) {
     case Intrinsic::dbg_declare:
     case Intrinsic::dbg_value:
+    case Intrinsic::dbg_label:
     case Intrinsic::lifetime_end:
       break;
     default:
@@ -4049,8 +4075,8 @@ bool SimplifyCFGOpt::SimplifyReturn(ReturnInst *RI, IRBuilder<> &Builder) {
   if (!UncondBranchPreds.empty() && DupRet) {
     while (!UncondBranchPreds.empty()) {
       BasicBlock *Pred = UncondBranchPreds.pop_back_val();
-      DEBUG(dbgs() << "FOLDING: " << *BB
-                   << "INTO UNCOND BRANCH PRED: " << *Pred);
+      LLVM_DEBUG(dbgs() << "FOLDING: " << *BB
+                        << "INTO UNCOND BRANCH PRED: " << *Pred);
       (void)FoldReturnIntoUncondBranch(RI, BB, Pred);
     }
 
@@ -4374,7 +4400,8 @@ static bool eliminateDeadSwitchCases(SwitchInst *SI, AssumptionCache *AC,
     if (Known.Zero.intersects(CaseVal) || !Known.One.isSubsetOf(CaseVal) ||
         (CaseVal.getMinSignedBits() > MaxSignificantBitsInCond)) {
       DeadCases.push_back(Case.getCaseValue());
-      DEBUG(dbgs() << "SimplifyCFG: switch case " << CaseVal << " is dead.\n");
+      LLVM_DEBUG(dbgs() << "SimplifyCFG: switch case " << CaseVal
+                        << " is dead.\n");
     }
   }
 
@@ -4390,7 +4417,7 @@ static bool eliminateDeadSwitchCases(SwitchInst *SI, AssumptionCache *AC,
   if (HasDefault && DeadCases.empty() &&
       NumUnknownBits < 64 /* avoid overflow */ &&
       SI->getNumCases() == (1ULL << NumUnknownBits)) {
-    DEBUG(dbgs() << "SimplifyCFG: switch default is dead.\n");
+    LLVM_DEBUG(dbgs() << "SimplifyCFG: switch default is dead.\n");
     BasicBlock *NewDefault =
         SplitBlockPredecessors(SI->getDefaultDest(), SI->getParent(), "");
     SI->setDefaultDest(&*NewDefault);
@@ -4607,24 +4634,20 @@ GetCaseResults(SwitchInst *SI, ConstantInt *CaseVal, BasicBlock *CaseDest,
   // which we can constant-propagate the CaseVal, continue to its successor.
   SmallDenseMap<Value *, Constant *> ConstantPool;
   ConstantPool.insert(std::make_pair(SI->getCondition(), CaseVal));
-  for (BasicBlock::iterator I = CaseDest->begin(), E = CaseDest->end(); I != E;
-       ++I) {
-    if (TerminatorInst *T = dyn_cast<TerminatorInst>(I)) {
+  for (Instruction &I :CaseDest->instructionsWithoutDebug()) {
+    if (TerminatorInst *T = dyn_cast<TerminatorInst>(&I)) {
       // If the terminator is a simple branch, continue to the next block.
       if (T->getNumSuccessors() != 1 || T->isExceptional())
         return false;
       Pred = CaseDest;
       CaseDest = T->getSuccessor(0);
-    } else if (isa<DbgInfoIntrinsic>(I)) {
-      // Skip debug intrinsic.
-      continue;
-    } else if (Constant *C = ConstantFold(&*I, DL, ConstantPool)) {
+    } else if (Constant *C = ConstantFold(&I, DL, ConstantPool)) {
       // 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()) {
+      for (auto &Use : I.uses()) {
         User *User = Use.getUser();
         if (Instruction *I = dyn_cast<Instruction>(User))
           if (I->getParent() == CaseDest)
@@ -4635,7 +4658,7 @@ GetCaseResults(SwitchInst *SI, ConstantInt *CaseVal, BasicBlock *CaseDest,
         return false;
       }
 
-      ConstantPool.insert(std::make_pair(&*I, C));
+      ConstantPool.insert(std::make_pair(&I, C));
     } else {
       break;
     }
@@ -4670,30 +4693,31 @@ GetCaseResults(SwitchInst *SI, ConstantInt *CaseVal, BasicBlock *CaseDest,
 }
 
 // Helper function used to add CaseVal to the list of cases that generate
-// Result.
-static void MapCaseToResult(ConstantInt *CaseVal,
-                            SwitchCaseResultVectorTy &UniqueResults,
-                            Constant *Result) {
+// Result. Returns the updated number of cases that generate this result.
+static uintptr_t MapCaseToResult(ConstantInt *CaseVal,
+                                 SwitchCaseResultVectorTy &UniqueResults,
+                                 Constant *Result) {
   for (auto &I : UniqueResults) {
     if (I.first == Result) {
       I.second.push_back(CaseVal);
-      return;
+      return I.second.size();
     }
   }
   UniqueResults.push_back(
       std::make_pair(Result, SmallVector<ConstantInt *, 4>(1, CaseVal)));
+  return 1;
 }
 
 // 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, PHINode *&PHI,
-                                  BasicBlock *&CommonDest,
-                                  SwitchCaseResultVectorTy &UniqueResults,
-                                  Constant *&DefaultResult,
-                                  const DataLayout &DL,
-                                  const TargetTransformInfo &TTI) {
+static bool
+InitializeUniqueCases(SwitchInst *SI, PHINode *&PHI, BasicBlock *&CommonDest,
+                      SwitchCaseResultVectorTy &UniqueResults,
+                      Constant *&DefaultResult, const DataLayout &DL,
+                      const TargetTransformInfo &TTI,
+                      uintptr_t MaxUniqueResults, uintptr_t MaxCasesPerResult) {
   for (auto &I : SI->cases()) {
     ConstantInt *CaseVal = I.getCaseValue();
 
@@ -4703,10 +4727,21 @@ static bool InitializeUniqueCases(SwitchInst *SI, PHINode *&PHI,
                         DL, TTI))
       return false;
 
-    // Only one value per case is permitted
+    // Only one value per case is permitted.
     if (Results.size() > 1)
       return false;
-    MapCaseToResult(CaseVal, UniqueResults, Results.begin()->second);
+
+    // Add the case->result mapping to UniqueResults.
+    const uintptr_t NumCasesForResult =
+        MapCaseToResult(CaseVal, UniqueResults, Results.begin()->second);
+
+    // Early out if there are too many cases for this result.
+    if (NumCasesForResult > MaxCasesPerResult)
+      return false;
+
+    // Early out if there are too many unique results.
+    if (UniqueResults.size() > MaxUniqueResults)
+      return false;
 
     // Check the PHI consistency.
     if (!PHI)
@@ -4806,7 +4841,7 @@ static bool switchToSelect(SwitchInst *SI, IRBuilder<> &Builder,
   SwitchCaseResultVectorTy UniqueResults;
   // Collect all the cases that will deliver the same value from the switch.
   if (!InitializeUniqueCases(SI, PHI, CommonDest, UniqueResults, DefaultResult,
-                             DL, TTI))
+                             DL, TTI, 2, 1))
     return false;
   // Selects choose between maximum two values.
   if (UniqueResults.size() != 2)
@@ -5384,8 +5419,7 @@ static bool SwitchToLookupTable(SwitchInst *SI, IRBuilder<> &Builder,
   }
 
   bool ReturnedEarly = false;
-  for (size_t I = 0, E = PHIs.size(); I != E; ++I) {
-    PHINode *PHI = PHIs[I];
+  for (PHINode *PHI : PHIs) {
     const ResultListTy &ResultList = ResultLists[PHI];
 
     // If using a bitmask, use any value to fill the lookup table holes.
@@ -5475,7 +5509,7 @@ static bool ReduceSwitchRange(SwitchInst *SI, IRBuilder<> &Builder,
   SmallVector<int64_t,4> Values;
   for (auto &C : SI->cases())
     Values.push_back(C.getCaseValue()->getValue().getSExtValue());
-  std::sort(Values.begin(), Values.end());
+  llvm::sort(Values.begin(), Values.end());
 
   // If the switch is already dense, there's nothing useful to do here.
   if (isSwitchDense(Values))
@@ -5558,11 +5592,7 @@ bool SimplifyCFGOpt::SimplifySwitch(SwitchInst *SI, IRBuilder<> &Builder) {
 
     // If the block only contains the switch, see if we can fold the block
     // away into any preds.
-    BasicBlock::iterator BBI = BB->begin();
-    // Ignore dbg intrinsics.
-    while (isa<DbgInfoIntrinsic>(BBI))
-      ++BBI;
-    if (SI == &*BBI)
+    if (SI == &*BB->instructionsWithoutDebug().begin())
       if (FoldValueComparisonIntoPredecessors(SI, Builder))
         return simplifyCFG(BB, TTI, Options) | true;
   }
@@ -5649,7 +5679,7 @@ bool SimplifyCFGOpt::SimplifyIndirectBr(IndirectBrInst *IBI) {
 /// any transform which might inhibit optimization (such as our ability to
 /// specialize a particular handler via tail commoning).  We do this by not
 /// merging any blocks which require us to introduce a phi.  Since the same
-/// values are flowing through both blocks, we don't loose any ability to
+/// values are flowing through both blocks, we don't lose any ability to
 /// specialize.  If anything, we make such specialization more likely.
 ///
 /// TODO - This transformation could remove entries from a phi in the target
@@ -5679,7 +5709,7 @@ static bool TryToMergeLandingPad(LandingPadInst *LPad, BranchInst *BI,
 
     // We've found an identical block.  Update our predecessors to take that
     // path instead and make ourselves dead.
-    SmallSet<BasicBlock *, 16> Preds;
+    SmallPtrSet<BasicBlock *, 16> Preds;
     Preds.insert(pred_begin(BB), pred_end(BB));
     for (BasicBlock *Pred : Preds) {
       InvokeInst *II = cast<InvokeInst>(Pred->getTerminator());
@@ -5697,7 +5727,7 @@ static bool TryToMergeLandingPad(LandingPadInst *LPad, BranchInst *BI,
         Inst.eraseFromParent();
     }
 
-    SmallSet<BasicBlock *, 16> Succs;
+    SmallPtrSet<BasicBlock *, 16> Succs;
     Succs.insert(succ_begin(BB), succ_end(BB));
     for (BasicBlock *Succ : Succs) {
       Succ->removePredecessor(BB);
@@ -5721,9 +5751,12 @@ bool SimplifyCFGOpt::SimplifyUncondBranch(BranchInst *BI,
   // header. (This is for early invocations before loop simplify and
   // vectorization to keep canonical loop forms for nested loops. These blocks
   // can be eliminated when the pass is invoked later in the back-end.)
+  // Note that if BB has only one predecessor then we do not introduce new
+  // backedge, so we can eliminate BB.
   bool NeedCanonicalLoop =
       Options.NeedCanonicalLoop &&
-      (LoopHeaders && (LoopHeaders->count(BB) || LoopHeaders->count(Succ)));
+      (LoopHeaders && pred_size(BB) > 1 &&
+       (LoopHeaders->count(BB) || LoopHeaders->count(Succ)));
   BasicBlock::iterator I = BB->getFirstNonPHIOrDbg()->getIterator();
   if (I->isTerminator() && BB != &BB->getParent()->getEntryBlock() &&
       !NeedCanonicalLoop && TryToSimplifyUncondBranchFromEmptyBlock(BB))
@@ -5771,6 +5804,9 @@ static BasicBlock *allPredecessorsComeFromSameSource(BasicBlock *BB) {
 
 bool SimplifyCFGOpt::SimplifyCondBranch(BranchInst *BI, IRBuilder<> &Builder) {
   BasicBlock *BB = BI->getParent();
+  const Function *Fn = BB->getParent();
+  if (Fn && Fn->hasFnAttribute(Attribute::OptForFuzzing))
+    return false;
 
   // Conditional branch
   if (isValueEqualityComparison(BI)) {
@@ -5783,18 +5819,12 @@ bool SimplifyCFGOpt::SimplifyCondBranch(BranchInst *BI, IRBuilder<> &Builder) {
 
     // This block must be empty, except for the setcond inst, if it exists.
     // Ignore dbg intrinsics.
-    BasicBlock::iterator I = BB->begin();
-    // Ignore dbg intrinsics.
-    while (isa<DbgInfoIntrinsic>(I))
-      ++I;
+    auto I = BB->instructionsWithoutDebug().begin();
     if (&*I == BI) {
       if (FoldValueComparisonIntoPredecessors(BI, Builder))
         return simplifyCFG(BB, TTI, Options) | 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, Options) | true;
     }
@@ -5920,17 +5950,20 @@ static bool passingValueIsAlwaysUndefined(Value *V, Instruction *I) {
     // Load from null is undefined.
     if (LoadInst *LI = dyn_cast<LoadInst>(Use))
       if (!LI->isVolatile())
-        return LI->getPointerAddressSpace() == 0;
+        return !NullPointerIsDefined(LI->getFunction(),
+                                     LI->getPointerAddressSpace());
 
     // Store to null is undefined.
     if (StoreInst *SI = dyn_cast<StoreInst>(Use))
       if (!SI->isVolatile())
-        return SI->getPointerAddressSpace() == 0 &&
+        return (!NullPointerIsDefined(SI->getFunction(),
+                                      SI->getPointerAddressSpace())) &&
                SI->getPointerOperand() == I;
 
     // A call to null is undefined.
     if (auto CS = CallSite(Use))
-      return CS.getCalledValue() == I;
+      return !NullPointerIsDefined(CS->getFunction()) &&
+             CS.getCalledValue() == I;
   }
   return false;
 }
@@ -5971,7 +6004,7 @@ bool SimplifyCFGOpt::run(BasicBlock *BB) {
   // or that just have themself as a predecessor.  These are unreachable.
   if ((pred_empty(BB) && BB != &BB->getParent()->getEntryBlock()) ||
       BB->getSinglePredecessor() == BB) {
-    DEBUG(dbgs() << "Removing BB: \n" << *BB);
+    LLVM_DEBUG(dbgs() << "Removing BB: \n" << *BB);
     DeleteDeadBlock(BB);
     return true;
   }