diff options
| -rw-r--r-- | lib/Transforms/Scalar/CondPropagate.cpp | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/lib/Transforms/Scalar/CondPropagate.cpp b/lib/Transforms/Scalar/CondPropagate.cpp index 101acef6dc..49c87fd02f 100644 --- a/lib/Transforms/Scalar/CondPropagate.cpp +++ b/lib/Transforms/Scalar/CondPropagate.cpp @@ -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(); |