1 files changed, 15 insertions, 95 deletions

diff --git a/lib/Transforms/Scalar/MemCpyOptimizer.cpp b/lib/Transforms/Scalar/MemCpyOptimizer.cpp
index 5a055139be4f..2364748efb05 100644
--- a/lib/Transforms/Scalar/MemCpyOptimizer.cpp
+++ b/lib/Transforms/Scalar/MemCpyOptimizer.cpp
@@ -69,90 +69,6 @@ STATISTIC(NumMemSetInfer, "Number of memsets inferred");
 STATISTIC(NumMoveToCpy,   "Number of memmoves converted to memcpy");
 STATISTIC(NumCpyToSet,    "Number of memcpys converted to memset");
 
-static int64_t GetOffsetFromIndex(const GEPOperator *GEP, unsigned Idx,
-                                  bool &VariableIdxFound,
-                                  const DataLayout &DL) {
-  // Skip over the first indices.
-  gep_type_iterator GTI = gep_type_begin(GEP);
-  for (unsigned i = 1; i != Idx; ++i, ++GTI)
-    /*skip along*/;
-
-  // Compute the offset implied by the rest of the indices.
-  int64_t Offset = 0;
-  for (unsigned i = Idx, e = GEP->getNumOperands(); i != e; ++i, ++GTI) {
-    ConstantInt *OpC = dyn_cast<ConstantInt>(GEP->getOperand(i));
-    if (!OpC)
-      return VariableIdxFound = true;
-    if (OpC->isZero()) continue;  // No offset.
-
-    // Handle struct indices, which add their field offset to the pointer.
-    if (StructType *STy = GTI.getStructTypeOrNull()) {
-      Offset += DL.getStructLayout(STy)->getElementOffset(OpC->getZExtValue());
-      continue;
-    }
-
-    // Otherwise, we have a sequential type like an array or vector.  Multiply
-    // the index by the ElementSize.
-    uint64_t Size = DL.getTypeAllocSize(GTI.getIndexedType());
-    Offset += Size*OpC->getSExtValue();
-  }
-
-  return Offset;
-}
-
-/// Return true if Ptr1 is provably equal to Ptr2 plus a constant offset, and
-/// return that constant offset. For example, Ptr1 might be &A[42], and Ptr2
-/// might be &A[40]. In this case offset would be -8.
-static bool IsPointerOffset(Value *Ptr1, Value *Ptr2, int64_t &Offset,
-                            const DataLayout &DL) {
-  Ptr1 = Ptr1->stripPointerCasts();
-  Ptr2 = Ptr2->stripPointerCasts();
-
-  // Handle the trivial case first.
-  if (Ptr1 == Ptr2) {
-    Offset = 0;
-    return true;
-  }
-
-  GEPOperator *GEP1 = dyn_cast<GEPOperator>(Ptr1);
-  GEPOperator *GEP2 = dyn_cast<GEPOperator>(Ptr2);
-
-  bool VariableIdxFound = false;
-
-  // If one pointer is a GEP and the other isn't, then see if the GEP is a
-  // constant offset from the base, as in "P" and "gep P, 1".
-  if (GEP1 && !GEP2 && GEP1->getOperand(0)->stripPointerCasts() == Ptr2) {
-    Offset = -GetOffsetFromIndex(GEP1, 1, VariableIdxFound, DL);
-    return !VariableIdxFound;
-  }
-
-  if (GEP2 && !GEP1 && GEP2->getOperand(0)->stripPointerCasts() == Ptr1) {
-    Offset = GetOffsetFromIndex(GEP2, 1, VariableIdxFound, DL);
-    return !VariableIdxFound;
-  }
-
-  // Right now we handle the case when Ptr1/Ptr2 are both GEPs with an identical
-  // base.  After that base, they may have some number of common (and
-  // potentially variable) indices.  After that they handle some constant
-  // offset, which determines their offset from each other.  At this point, we
-  // handle no other case.
-  if (!GEP1 || !GEP2 || GEP1->getOperand(0) != GEP2->getOperand(0))
-    return false;
-
-  // Skip any common indices and track the GEP types.
-  unsigned Idx = 1;
-  for (; Idx != GEP1->getNumOperands() && Idx != GEP2->getNumOperands(); ++Idx)
-    if (GEP1->getOperand(Idx) != GEP2->getOperand(Idx))
-      break;
-
-  int64_t Offset1 = GetOffsetFromIndex(GEP1, Idx, VariableIdxFound, DL);
-  int64_t Offset2 = GetOffsetFromIndex(GEP2, Idx, VariableIdxFound, DL);
-  if (VariableIdxFound) return false;
-
-  Offset = Offset2-Offset1;
-  return true;
-}
-
 namespace {
 
 /// Represents a range of memset'd bytes with the ByteVal value.
@@ -419,12 +335,12 @@ Instruction *MemCpyOptPass::tryMergingIntoMemset(Instruction *StartInst,
         break;
 
       // Check to see if this store is to a constant offset from the start ptr.
-      int64_t Offset;
-      if (!IsPointerOffset(StartPtr, NextStore->getPointerOperand(), Offset,
-                           DL))
+      Optional<int64_t> Offset =
+          isPointerOffset(StartPtr, NextStore->getPointerOperand(), DL);
+      if (!Offset)
         break;
 
-      Ranges.addStore(Offset, NextStore);
+      Ranges.addStore(*Offset, NextStore);
     } else {
       MemSetInst *MSI = cast<MemSetInst>(BI);
 
@@ -433,11 +349,11 @@ Instruction *MemCpyOptPass::tryMergingIntoMemset(Instruction *StartInst,
         break;
 
       // Check to see if this store is to a constant offset from the start ptr.
-      int64_t Offset;
-      if (!IsPointerOffset(StartPtr, MSI->getDest(), Offset, DL))
+      Optional<int64_t> Offset = isPointerOffset(StartPtr, MSI->getDest(), DL);
+      if (!Offset)
         break;
 
-      Ranges.addMemSet(Offset, MSI);
+      Ranges.addMemSet(*Offset, MSI);
     }
   }
 
@@ -597,9 +513,13 @@ static bool moveUp(AliasAnalysis &AA, StoreInst *SI, Instruction *P,
 
     ToLift.push_back(C);
     for (unsigned k = 0, e = C->getNumOperands(); k != e; ++k)
-      if (auto *A = dyn_cast<Instruction>(C->getOperand(k)))
-        if (A->getParent() == SI->getParent())
+      if (auto *A = dyn_cast<Instruction>(C->getOperand(k))) {
+        if (A->getParent() == SI->getParent()) {
+          // Cannot hoist user of P above P
+          if(A == P) return false;
           Args.insert(A);
+        }
+      }
   }
 
   // We made it, we need to lift
@@ -979,7 +899,7 @@ bool MemCpyOptPass::performCallSlotOptzn(Instruction *cpy, Value *cpyDest,
   // If the destination wasn't sufficiently aligned then increase its alignment.
   if (!isDestSufficientlyAligned) {
     assert(isa<AllocaInst>(cpyDest) && "Can only increase alloca alignment!");
-    cast<AllocaInst>(cpyDest)->setAlignment(srcAlign);
+    cast<AllocaInst>(cpyDest)->setAlignment(MaybeAlign(srcAlign));
   }
 
   // Drop any cached information about the call, because we may have changed
@@ -1516,7 +1436,7 @@ bool MemCpyOptLegacyPass::runOnFunction(Function &F) {
     return false;
 
   auto *MD = &getAnalysis<MemoryDependenceWrapperPass>().getMemDep();
-  auto *TLI = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
+  auto *TLI = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F);
 
   auto LookupAliasAnalysis = [this]() -> AliasAnalysis & {
     return getAnalysis<AAResultsWrapperPass>().getAAResults();