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Add code to ensure that no PHI nodes are left laying around with their 

arguments dropped.  This fixes bug:
   test/Regression/Transforms/ADCE/2002-07-17-PHIAssertion.ll

llvm-svn: 3134
This commit is contained in:
Chris Lattner 2002-07-29 23:40:46 +00:00
parent 2511b6e296
commit 3be5d0b892
1 changed files with 16 additions and 2 deletions
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18
llvm/lib/Transforms/Scalar/ADCE.cpp
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@ -284,9 +284,23 @@ bool ADCE::doADCE() {
// sweep over the program can safely delete dead instructions without // sweep over the program can safely delete dead instructions without
// other dead instructions still refering to them. // other dead instructions still refering to them.
// //
for (BasicBlock::iterator I = BB->begin(), E = --BB->end(); I != E; ++I) for (BasicBlock::iterator I = BB->begin(), E = --BB->end(); I != E; )
if (!LiveSet.count(I)) // Is this instruction alive? if (!LiveSet.count(I)) { // Is this instruction alive?
I->dropAllReferences(); // Nope, drop references... I->dropAllReferences(); // Nope, drop references...
if (PHINode *PN = dyn_cast<PHINode>(&*I)) {
// We don't want to leave PHI nodes in the program that have
// #arguments != #predecessors, so we remove them now.
//
PN->replaceAllUsesWith(Constant::getNullValue(PN->getType()));
// Delete the instruction...
I = BB->getInstList().erase(I);
} else {
++I;
}
} else {
++I;
}
} }
} }