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eliminate getBitCastOperand and simplify some over-complex inbounds stuff.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92708 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2010-01-05 07:42:10 +00:00
parent 753a2b464d
commit 948cdeba97
1 changed files with 22 additions and 46 deletions
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68
lib/Transforms/InstCombine/InstructionCombining.cpp
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@ -103,23 +103,6 @@ bool InstCombiner::ShouldChangeType(const Type *From, const Type *To) const {
return true;
}
/// getBitCastOperand - If the specified operand is a CastInst, a constant
/// expression bitcast, or a GetElementPtrInst with all zero indices, return the
/// operand value, otherwise return null.
// FIXME: Value::stripPointerCasts
static Value *getBitCastOperand(Value *V) {
if (Operator *O = dyn_cast<Operator>(V)) {
if (O->getOpcode() == Instruction::BitCast)
return O->getOperand(0);
if (GEPOperator *GEP = dyn_cast<GEPOperator>(V))
if (GEP->hasAllZeroIndices())
return GEP->getPointerOperand();
}
return 0;
}
// SimplifyCommutative - This performs a few simplifications for commutative
// operators:
@ -2925,8 +2908,7 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
}
if (!Indices.empty())
return (cast<GEPOperator>(&GEP)->isInBounds() &&
Src->isInBounds()) ?
return (GEP.isInBounds() && Src->isInBounds()) ?
GetElementPtrInst::CreateInBounds(Src->getOperand(0), Indices.begin(),
Indices.end(), GEP.getName()) :
GetElementPtrInst::Create(Src->getOperand(0), Indices.begin(),
@ -2934,16 +2916,10 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
}
// Handle gep(bitcast x) and gep(gep x, 0, 0, 0).
if (Value *X = getBitCastOperand(PtrOp)) {
assert(isa<PointerType>(X->getType()) && "Must be cast from pointer");
Value *StrippedPtr = PtrOp->stripPointerCasts();
if (StrippedPtr != PtrOp) {
const PointerType *StrippedPtrTy =cast<PointerType>(StrippedPtr->getType());
// If the input bitcast is actually "bitcast(bitcast(x))", then we don't
// want to change the gep until the bitcasts are eliminated.
if (getBitCastOperand(X)) {
Worklist.AddValue(PtrOp);
return 0;
}
bool HasZeroPointerIndex = false;
if (ConstantInt *C = dyn_cast<ConstantInt>(GEP.getOperand(1)))
HasZeroPointerIndex = C->isZero();
@ -2957,21 +2933,21 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
// This occurs when the program declares an array extern like "int X[];"
if (HasZeroPointerIndex) {
const PointerType *CPTy = cast<PointerType>(PtrOp->getType());
const PointerType *XTy = cast<PointerType>(X->getType());
if (const ArrayType *CATy =
dyn_cast<ArrayType>(CPTy->getElementType())) {
// GEP (bitcast i8* X to [0 x i8]*), i32 0, ... ?
if (CATy->getElementType() == XTy->getElementType()) {
if (CATy->getElementType() == StrippedPtrTy->getElementType()) {
// -> GEP i8* X, ...
SmallVector<Value*, 8> Indices(GEP.idx_begin()+1, GEP.idx_end());
return cast<GEPOperator>(&GEP)->isInBounds() ?
GetElementPtrInst::CreateInBounds(X, Indices.begin(), Indices.end(),
GEP.getName()) :
GetElementPtrInst::Create(X, Indices.begin(), Indices.end(),
GEP.getName());
SmallVector<Value*, 8> Idx(GEP.idx_begin()+1, GEP.idx_end());
GetElementPtrInst *Res =
GetElementPtrInst::Create(StrippedPtr, Idx.begin(),
Idx.end(), GEP.getName());
Res->setIsInBounds(GEP.isInBounds());
return Res;
}
if (const ArrayType *XATy = dyn_cast<ArrayType>(XTy->getElementType())){
if (const ArrayType *XATy =
dyn_cast<ArrayType>(StrippedPtrTy->getElementType())){
// GEP (bitcast [10 x i8]* X to [0 x i8]*), i32 0, ... ?
if (CATy->getElementType() == XATy->getElementType()) {
// -> GEP [10 x i8]* X, i32 0, ...
@ -2979,7 +2955,7 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
// to an array of the same type as the destination pointer
// array. Because the array type is never stepped over (there
// is a leading zero) we can fold the cast into this GEP.
GEP.setOperand(0, X);
GEP.setOperand(0, StrippedPtr);
return &GEP;
}
}
@ -2988,7 +2964,7 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
// Transform things like:
// %t = getelementptr i32* bitcast ([2 x i32]* %str to i32*), i32 %V
// into: %t1 = getelementptr [2 x i32]* %str, i32 0, i32 %V; bitcast
const Type *SrcElTy = cast<PointerType>(X->getType())->getElementType();
const Type *SrcElTy = StrippedPtrTy->getElementType();
const Type *ResElTy=cast<PointerType>(PtrOp->getType())->getElementType();
if (TD && isa<ArrayType>(SrcElTy) &&
TD->getTypeAllocSize(cast<ArrayType>(SrcElTy)->getElementType()) ==
@ -2996,9 +2972,9 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
Value *Idx[2];
Idx[0] = Constant::getNullValue(Type::getInt32Ty(GEP.getContext()));
Idx[1] = GEP.getOperand(1);
Value *NewGEP = cast<GEPOperator>(&GEP)->isInBounds() ?
Builder->CreateInBoundsGEP(X, Idx, Idx + 2, GEP.getName()) :
Builder->CreateGEP(X, Idx, Idx + 2, GEP.getName());
Value *NewGEP = GEP.isInBounds() ?
Builder->CreateInBoundsGEP(StrippedPtr, Idx, Idx + 2, GEP.getName()) :
Builder->CreateGEP(StrippedPtr, Idx, Idx + 2, GEP.getName());
// V and GEP are both pointer types --> BitCast
return new BitCastInst(NewGEP, GEP.getType());
}
@ -3056,9 +3032,9 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
Value *Idx[2];
Idx[0] = Constant::getNullValue(Type::getInt32Ty(GEP.getContext()));
Idx[1] = NewIdx;
Value *NewGEP = cast<GEPOperator>(&GEP)->isInBounds() ?
Builder->CreateInBoundsGEP(X, Idx, Idx + 2, GEP.getName()) :
Builder->CreateGEP(X, Idx, Idx + 2, GEP.getName());
Value *NewGEP = GEP.isInBounds() ?
Builder->CreateInBoundsGEP(StrippedPtr, Idx, Idx + 2,GEP.getName()):
Builder->CreateGEP(StrippedPtr, Idx, Idx + 2, GEP.getName());
// The NewGEP must be pointer typed, so must the old one -> BitCast
return new BitCastInst(NewGEP, GEP.getType());
}
@ -3106,7 +3082,7 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
const Type *InTy =
cast<PointerType>(BCI->getOperand(0)->getType())->getElementType();
if (FindElementAtOffset(InTy, Offset, NewIndices)) {
Value *NGEP = cast<GEPOperator>(&GEP)->isInBounds() ?
Value *NGEP = GEP.isInBounds() ?
Builder->CreateInBoundsGEP(BCI->getOperand(0), NewIndices.begin(),
NewIndices.end()) :
Builder->CreateGEP(BCI->getOperand(0), NewIndices.begin(),