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move some code, check to see if the input to the GEP is a bitcast

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(which is constant time and cheap) before checking hasAllZeroIndices.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61976 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2009-01-09 04:53:57 +00:00
parent 5446274bd2
commit 5840779cc9
1 changed files with 22 additions and 23 deletions
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45
lib/Transforms/Scalar/InstructionCombining.cpp
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@ -10464,28 +10464,6 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
}
if (MadeChange) return &GEP;
// If this GEP instruction doesn't move the pointer, and if the input operand
// is a bitcast of another pointer, just replace the GEP with a bitcast of the
// real input to the dest type.
if (GEP.hasAllZeroIndices()) {
if (BitCastInst *BCI = dyn_cast<BitCastInst>(GEP.getOperand(0))) {
// 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<AllocationInst>(BCI->getOperand(0))) {
// See if the bitcast simplifies, if so, don't nuke this GEP yet.
if (Instruction *I = visitBitCast(*BCI)) {
if (I != BCI) {
I->takeName(BCI);
BCI->getParent()->getInstList().insert(BCI, I);
ReplaceInstUsesWith(*BCI, I);
}
return &GEP;
}
}
return new BitCastInst(BCI->getOperand(0), GEP.getType());
}
}
// Combine Indices - If the source pointer to this getelementptr instruction
// is a getelementptr instruction, combine the indices of the two
// getelementptr instructions into a single instruction.
@ -10696,7 +10674,28 @@ Instruction *InstCombiner::visitGetElementPtrInst(GetElementPtrInst &GEP) {
}
}
}
if (BitCastInst *BCI = dyn_cast<BitCastInst>(PtrOp)) {
// If this GEP instruction doesn't move the pointer, just replace the GEP
// with a bitcast of the real input to the dest type.
if (GEP.hasAllZeroIndices()) {
// 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<AllocationInst>(BCI->getOperand(0))) {
// See if the bitcast simplifies, if so, don't nuke this GEP yet.
if (Instruction *I = visitBitCast(*BCI)) {
if (I != BCI) {
I->takeName(BCI);
BCI->getParent()->getInstList().insert(BCI, I);
ReplaceInstUsesWith(*BCI, I);
}
return &GEP;
}
}
return new BitCastInst(BCI->getOperand(0), GEP.getType());
}
}
return 0;
}