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-rw-r--r--lib/VMCore/BasicBlock.cpp10
1 files changed, 9 insertions, 1 deletions
diff --git a/lib/VMCore/BasicBlock.cpp b/lib/VMCore/BasicBlock.cpp
index 98d12d8f13..407080cf68 100644
--- a/lib/VMCore/BasicBlock.cpp
+++ b/lib/VMCore/BasicBlock.cpp
@@ -189,8 +189,16 @@ void BasicBlock::removePredecessor(BasicBlock *Pred,
// Okay, now we know that we need to remove predecessor #pred_idx from all
// PHI nodes. Iterate over each PHI node fixing them up
PHINode *PN;
- for (iterator II = begin(); (PN = dyn_cast<PHINode>(II)); ++II)
+ for (iterator II = begin(); (PN = dyn_cast<PHINode>(II)); ++II) {
PN->removeIncomingValue(Pred, false);
+ // If all incoming values to the Phi are the same, we can replace the Phi
+ // with that value.
+ if (Value *PNV = PN->hasConstantValue())
+ if (!isa<Instruction>(PNV)) {
+ PN->replaceAllUsesWith(PNV);
+ PN->eraseFromParent();
+ }
+ }
}
}