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Implement select.ll:test16: fold load (select C, X, null) -> load X

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16499 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2004-09-23 15:46:00 +00:00
parent 60a11f1970
commit 684fe210a9
1 changed files with 14 additions and 0 deletions
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14
lib/Transforms/Scalar/InstructionCombining.cpp
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@ -3071,6 +3071,20 @@ Instruction *InstCombiner::visitLoadInst(LoadInst &LI) {
return new SelectInst(SI->getCondition(), V1, V2);
}
// load (select (cond, null, P)) -> load P
if (Constant *C = dyn_cast<Constant>(SI->getOperand(1)))
if (C->isNullValue()) {
LI.setOperand(0, SI->getOperand(2));
return &LI;
}
// load (select (cond, P, null)) -> load P
if (Constant *C = dyn_cast<Constant>(SI->getOperand(2)))
if (C->isNullValue()) {
LI.setOperand(0, SI->getOperand(1));
return &LI;
}
} else if (PHINode *PN = dyn_cast<PHINode>(Op)) {
// load (phi (&V1, &V2, &V3)) --> phi(load &V1, load &V2, load &V3)
bool Safe = PN->getParent() == LI.getParent();