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Handle single-entry PHI nodes correctly. This fixes PR877 and 

Transforms/CondProp/2006-08-14-SingleEntryPhiCrash.ll

llvm-svn: 29673
This commit is contained in:
Chris Lattner 2006-08-14 21:38:05 +00:00
parent c5bbda70e3
commit 6441cf93c9
1 changed files with 11 additions and 1 deletions
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12
llvm/lib/Transforms/Scalar/CondPropagate.cpp
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@ -87,8 +87,18 @@ void CondProp::SimplifyBlock(BasicBlock *BB) {
// If this block ends with an unconditional branch and the only successor has
// only this block as a predecessor, merge the two blocks together.
if (BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator()))
if (BI->isUnconditional() && BI->getSuccessor(0)->getSinglePredecessor()) {
if (BI->isUnconditional() && BI->getSuccessor(0)->getSinglePredecessor() &&
BB != BI->getSuccessor(0)) {
BasicBlock *Succ = BI->getSuccessor(0);
// If Succ has any PHI nodes, they are all single-entry PHI's.
while (PHINode *PN = dyn_cast<PHINode>(Succ->begin())) {
assert(PN->getNumIncomingValues() == 1 &&
"PHI doesn't match parent block");
PN->replaceAllUsesWith(PN->getIncomingValue(0));
PN->eraseFromParent();
}
// Remove BI.
BI->eraseFromParent();