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Hopefully the final attempt at making IndVars preserve LCSSA. 

This should fix PR 831.

llvm-svn: 29141
This commit is contained in:
Owen Anderson 2006-07-14 18:49:15 +00:00
parent 96aecb5d76
commit bea70ee1de
1 changed files with 30 additions and 2 deletions
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32
llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
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@ -358,8 +358,36 @@ void IndVarSimplify::RewriteLoopExitValues(Loop *L) {
// Rewrite any users of the computed value outside of the loop // Rewrite any users of the computed value outside of the loop
// with the newly computed value. // with the newly computed value.
for (unsigned i = 0, e = ExtraLoopUsers.size(); i != e; ++i) for (unsigned i = 0, e = ExtraLoopUsers.size(); i != e; ++i) {
ExtraLoopUsers[i]->replaceUsesOfWith(I, NewVal); PHINode* PN = dyn_cast<PHINode>(ExtraLoopUsers[i]);
if (PN && PN->getNumOperands() == 2 &&
!L->contains(PN->getParent())) {
// We're dealing with an LCSSA Phi. Handle it specially.
Instruction* LCSSAInsertPt = BlockToInsertInto->begin();
Instruction* NewInstr = dyn_cast<Instruction>(NewVal);
if (NewInstr && !isa<PHINode>(NewInstr) &&
!L->contains(NewInstr->getParent()))
for (unsigned j = 0; j < NewInstr->getNumOperands(); ++j){
Instruction* PredI =
dyn_cast<Instruction>(NewInstr->getOperand(j));
if (PredI && L->contains(PredI->getParent())) {
PHINode* NewLCSSA = new PHINode(PredI->getType(),
PredI->getName() + ".lcssa",
LCSSAInsertPt);
NewLCSSA->addIncoming(PredI,
BlockToInsertInto->getSinglePredecessor());
NewInstr->replaceUsesOfWith(PredI, NewLCSSA);
}
}
PN->replaceAllUsesWith(NewVal);
PN->eraseFromParent();
} else {
ExtraLoopUsers[i]->replaceUsesOfWith(I, NewVal);
}
}
// If this instruction is dead now, schedule it to be removed. // If this instruction is dead now, schedule it to be removed.
if (I->use_empty()) if (I->use_empty())