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Implement test/Regression/Transforms/InstCombine/getelementptr_index.ll

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12762 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2004-04-07 18:38:20 +00:00
parent ef09aab9ce
commit cb69a4ed64
1 changed files with 38 additions and 23 deletions
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61
lib/Transforms/Scalar/InstructionCombining.cpp
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@ -2317,32 +2317,47 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
// Eliminate unneeded casts for indices.
bool MadeChange = false;
for (unsigned i = 1, e = GEP.getNumOperands(); i != e; ++i)
if (CastInst *CI = dyn_cast<CastInst>(GEP.getOperand(i))) {
Value *Src = CI->getOperand(0);
const Type *SrcTy = Src->getType();
const Type *DestTy = CI->getType();
if (Src->getType()->isInteger()) {
if (SrcTy->getPrimitiveSize() == DestTy->getPrimitiveSize()) {
// We can always eliminate a cast from ulong or long to the other. We
// can always eliminate a cast from uint to int or the other on 32-bit
// pointer platforms.
if (DestTy->getPrimitiveSize() >= TD->getPointerSize()) {
MadeChange = true;
GEP.setOperand(i, Src);
}
} else if (SrcTy->getPrimitiveSize() < DestTy->getPrimitiveSize() &&
SrcTy->getPrimitiveSize() == 4) {
// We can always eliminate a cast from int to [u]long. We can
// eliminate a cast from uint to [u]long iff the target is a 32-bit
// pointer target.
if (SrcTy->isSigned() ||
SrcTy->getPrimitiveSize() >= TD->getPointerSize()) {
MadeChange = true;
GEP.setOperand(i, Src);
gep_type_iterator GTI = gep_type_begin(GEP);
for (unsigned i = 1, e = GEP.getNumOperands(); i != e; ++i, ++GTI)
if (isa<SequentialType>(*GTI)) {
if (CastInst *CI = dyn_cast<CastInst>(GEP.getOperand(i))) {
Value *Src = CI->getOperand(0);
const Type *SrcTy = Src->getType();
const Type *DestTy = CI->getType();
if (Src->getType()->isInteger()) {
if (SrcTy->getPrimitiveSize() == DestTy->getPrimitiveSize()) {
// We can always eliminate a cast from ulong or long to the other.
// We can always eliminate a cast from uint to int or the other on
// 32-bit pointer platforms.
if (DestTy->getPrimitiveSize() >= TD->getPointerSize()) {
MadeChange = true;
GEP.setOperand(i, Src);
}
} else if (SrcTy->getPrimitiveSize() < DestTy->getPrimitiveSize() &&
SrcTy->getPrimitiveSize() == 4) {
// We can always eliminate a cast from int to [u]long. We can
// eliminate a cast from uint to [u]long iff the target is a 32-bit
// pointer target.
if (SrcTy->isSigned() ||
SrcTy->getPrimitiveSize() >= TD->getPointerSize()) {
MadeChange = true;
GEP.setOperand(i, Src);
}
}
}
}
// If we are using a wider index than needed for this platform, shrink it
// to what we need. If the incoming value needs a cast instruction,
// insert it. This explicit cast can make subsequent optimizations more
// obvious.
Value *Op = GEP.getOperand(i);
if (Op->getType()->getPrimitiveSize() > TD->getPointerSize())
if (!isa<Constant>(Op)) {
Op = InsertNewInstBefore(new CastInst(Op, TD->getIntPtrType(),
Op->getName()), GEP);
GEP.setOperand(i, Op);
MadeChange = true;
}
}
if (MadeChange) return &GEP;