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commonPointerCast cleanups to make address space change easier

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188719 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Matt Arsenault 2013-08-19 22:17:18 +00:00
parent b937c55e93
commit 5c40cc2e1e
1 changed files with 11 additions and 5 deletions
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12
lib/Transforms/InstCombine/InstCombineCasts.cpp
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@ -1370,15 +1370,21 @@ Instruction *InstCombiner::commonPointerCastTransforms(CastInst &CI) {
return &CI;
}
if (!TD)
return commonCastTransforms(CI);
// If the GEP has a single use, and the base pointer is a bitcast, and the
// GEP computes a constant offset, see if we can convert these three
// instructions into fewer. This typically happens with unions and other
// non-type-safe code.
APInt Offset(TD ? TD->getPointerSizeInBits() : 1, 0);
if (TD && GEP->hasOneUse() && isa<BitCastInst>(GEP->getOperand(0)) &&
unsigned OffsetBits = TD->getPointerSizeInBits();
APInt Offset(OffsetBits, 0);
BitCastInst *BCI = dyn_cast<BitCastInst>(GEP->getOperand(0));
if (GEP->hasOneUse() &&
BCI &&
GEP->accumulateConstantOffset(*TD, Offset)) {
// Get the base pointer input of the bitcast, and the type it points to.
Value *OrigBase = cast<BitCastInst>(GEP->getOperand(0))->getOperand(0);
Value *OrigBase = BCI->getOperand(0);
Type *GEPIdxTy = OrigBase->getType()->getPointerElementType();
SmallVector<Value*, 8> NewIndices;
if (FindElementAtOffset(GEPIdxTy, Offset.getSExtValue(), NewIndices)) {