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Move the "gep undef" -> "undef" transform from instcombine to

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InstructionSimplify.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119970 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Duncan Sands 2010-11-22 13:42:49 +00:00
parent ad8aaa069c
commit 85bbff6c94
2 changed files with 11 additions and 7 deletions
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15
lib/Analysis/InstructionSimplify.cpp
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@ -691,13 +691,20 @@ Value *llvm::SimplifySelectInst(Value *CondVal, Value *TrueVal, Value *FalseVal,
/// fold the result. If not, this returns null.
Value *llvm::SimplifyGEPInst(Value *const *Ops, unsigned NumOps,
const TargetData *TD, const DominatorTree *) {
// The type of the GEP pointer operand.
const PointerType *PtrTy = cast<PointerType>(Ops[0]->getType());
// getelementptr P -> P.
if (NumOps == 1)
return Ops[0];
// TODO.
//if (isa<UndefValue>(Ops[0]))
// return UndefValue::get(GEP.getType());
if (isa<UndefValue>(Ops[0])) {
// Compute the (pointer) type returned by the GEP instruction.
const Type *LastType = GetElementPtrInst::getIndexedType(PtrTy, &Ops[1],
NumOps-1);
const Type *GEPTy = PointerType::get(LastType, PtrTy->getAddressSpace());
return UndefValue::get(GEPTy);
}
if (NumOps == 2) {
// getelementptr P, 0 -> P.
@ -706,7 +713,7 @@ Value *llvm::SimplifyGEPInst(Value *const *Ops, unsigned NumOps,
return Ops[0];
// getelementptr P, N -> P if P points to a type of zero size.
if (TD) {
const Type *Ty = cast<PointerType>(Ops[0]->getType())->getElementType();
const Type *Ty = PtrTy->getElementType();
if (Ty->isSized() && !TD->getTypeAllocSize(Ty))
return Ops[0];
}

3
lib/Transforms/InstCombine/InstructionCombining.cpp
View File

@ -523,9 +523,6 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
Value *PtrOp = GEP.getOperand(0);
if (isa<UndefValue>(GEP.getOperand(0)))
return ReplaceInstUsesWith(GEP, UndefValue::get(GEP.getType()));
// Eliminate unneeded casts for indices.
if (TD) {
bool MadeChange = false;