diff options
| -rw-r--r-- | lib/Transforms/Scalar/ADCE.cpp | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/lib/Transforms/Scalar/ADCE.cpp b/lib/Transforms/Scalar/ADCE.cpp index bba30a1..56b219a 100644 --- a/lib/Transforms/Scalar/ADCE.cpp +++ b/lib/Transforms/Scalar/ADCE.cpp @@ -284,9 +284,23 @@ bool ADCE::doADCE() { // sweep over the program can safely delete dead instructions without // other dead instructions still refering to them. // - for (BasicBlock::iterator I = BB->begin(), E = --BB->end(); I != E; ++I) - if (!LiveSet.count(I)) // Is this instruction alive? + for (BasicBlock::iterator I = BB->begin(), E = --BB->end(); I != E; ) + if (!LiveSet.count(I)) { // Is this instruction alive? 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; + } } } |