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Cleanup visitGetElementPtr to make address space change easier

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188720 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Matt Arsenault 2013-08-19 22:17:34 +00:00
parent 5c40cc2e1e
commit c4ad982f0b
1 changed files with 13 additions and 11 deletions
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24
lib/Transforms/InstCombine/InstructionCombining.cpp
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@ -1319,15 +1319,20 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
}
}
if (!TD)
return 0;
/// See if we can simplify:
/// X = bitcast A* to B*
/// Y = gep X, <...constant indices...>
/// into a gep of the original struct. This is important for SROA and alias
/// analysis of unions. If "A" is also a bitcast, wait for A/X to be merged.
if (BitCastInst *BCI = dyn_cast<BitCastInst>(PtrOp)) {
APInt Offset(TD ? TD->getPointerSizeInBits() : 1, 0);
if (TD &&
!isa<BitCastInst>(BCI->getOperand(0)) &&
Value *Operand = BCI->getOperand(0);
PointerType *OpType = cast<PointerType>(Operand->getType());
unsigned OffsetBits = TD->getPointerSizeInBits();
APInt Offset(OffsetBits, 0);
if (!isa<BitCastInst>(Operand) &&
GEP.accumulateConstantOffset(*TD, Offset) &&
StrippedPtrTy->getAddressSpace() == GEP.getPointerAddressSpace()) {
@ -1336,8 +1341,7 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
if (!Offset) {
// If the bitcast is of an allocation, and the allocation will be
// converted to match the type of the cast, don't touch this.
if (isa<AllocaInst>(BCI->getOperand(0)) ||
isAllocationFn(BCI->getOperand(0), TLI)) {
if (isa<AllocaInst>(Operand) || isAllocationFn(Operand, TLI)) {
// See if the bitcast simplifies, if so, don't nuke this GEP yet.
if (Instruction *I = visitBitCast(*BCI)) {
if (I != BCI) {
@ -1348,18 +1352,18 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
return &GEP;
}
}
return new BitCastInst(BCI->getOperand(0), GEP.getType());
return new BitCastInst(Operand, GEP.getType());
}
// Otherwise, if the offset is non-zero, we need to find out if there is a
// field at Offset in 'A's type. If so, we can pull the cast through the
// GEP.
SmallVector<Value*, 8> NewIndices;
Type *InTy = BCI->getOperand(0)->getType()->getPointerElementType();
Type *InTy = OpType->getElementType();
if (FindElementAtOffset(InTy, Offset.getSExtValue(), NewIndices)) {
Value *NGEP = GEP.isInBounds() ?
Builder->CreateInBoundsGEP(BCI->getOperand(0), NewIndices) :
Builder->CreateGEP(BCI->getOperand(0), NewIndices);
Builder->CreateInBoundsGEP(Operand, NewIndices) :
Builder->CreateGEP(Operand, NewIndices);
if (NGEP->getType() == GEP.getType())
return ReplaceInstUsesWith(GEP, NGEP);
@ -1372,8 +1376,6 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
return 0;
}
static bool
isAllocSiteRemovable(Instruction *AI, SmallVectorImpl<WeakVH> &Users,
const TargetLibraryInfo *TLI) {