diff options
Diffstat (limited to 'lib/Transforms/Utils/SimplifyCFG.cpp')
| -rw-r--r-- | lib/Transforms/Utils/SimplifyCFG.cpp | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp index 426d18ec9f..59ea9865af 100644 --- a/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/lib/Transforms/Utils/SimplifyCFG.cpp @@ -143,7 +143,7 @@ bool SimplifyCFG(BasicBlock *BB) { // pred, and if there is only one distinct successor of the predecessor, and // if there are no PHI nodes. // - if (!isa<PHINode>(BB->front()) && !BB->hasConstantReferences()) { + if (!BB->hasConstantReferences()) { pred_iterator PI(pred_begin(BB)), PE(pred_end(BB)); BasicBlock *OnlyPred = *PI++; for (; PI != PE; ++PI) // Search all predecessors, see if they are all same @@ -168,6 +168,16 @@ bool SimplifyCFG(BasicBlock *BB) { //cerr << "Merging: " << BB << "into: " << OnlyPred; TerminatorInst *Term = OnlyPred->getTerminator(); + // Resolve any PHI nodes at the start of the block. They are all + // guaranteed to have exactly one entry if they exist. + // + while (PHINode *PN = dyn_cast<PHINode>(&BB->front())) { + assert(PN->getNumIncomingValues() == 1 && "Only one pred!"); + PN->replaceAllUsesWith(PN->getIncomingValue(0)); + BB->getInstList().pop_front(); // Delete the phi node... + } + + // Delete the unconditional branch from the predecessor... OnlyPred->getInstList().pop_back(); |