Handle PHINode with only one incoming value.
This fixes http://llvm.org/bugs/show_bug.cgi?id=979
llvm-svn: 31358
diff --git a/llvm/lib/Transforms/Scalar/CondPropagate.cpp b/llvm/lib/Transforms/Scalar/CondPropagate.cpp
index 5eb5abd9..d7aa7ec 100644
--- a/llvm/lib/Transforms/Scalar/CondPropagate.cpp
+++ b/llvm/lib/Transforms/Scalar/CondPropagate.cpp
@@ -196,11 +196,15 @@
// Get the old block we are threading through.
BasicBlock *OldSucc = FromBr->getSuccessor(0);
- // ToBB should not have any PHI nodes in it to update, because OldSucc had
- // multiple successors. If OldSucc had multiple successor and ToBB had
- // multiple predecessors, the edge between them would be critical, which we
- // already took care of.
- assert(!isa<PHINode>(ToBB->begin()) && "Critical Edge Found!");
+ // OldSucc had multiple successors. If ToBB has multiple predecessors, the
+ // edge between them would be critical, which we already took care of.
+ // If ToBB has single operand PHI node than take care of it here.
+ if (isa<PHINode>(ToBB->begin())) {
+ PHINode *PN = cast<PHINode>(ToBB->begin());
+ assert(PN->getNumIncomingValues() == 1 && "Critical Edge Found!");
+ PN->replaceAllUsesWith(PN->getIncomingValue(0));
+ PN->eraseFromParent();
+ }
// Update PHI nodes in OldSucc to know that FromBB no longer branches to it.
OldSucc->removePredecessor(FromBB);