make reassociate more careful about not leaving around dead mul's

llvm-svn: 92370

1 files changed, 7 insertions, 1 deletions

diff --git a/llvm/lib/Transforms/Scalar/Reassociate.cpp b/llvm/lib/Transforms/Scalar/Reassociate.cpp
index 8596dc70dad..365c9f79582 100644
--- a/llvm/lib/Transforms/Scalar/Reassociate.cpp
+++ b/llvm/lib/Transforms/Scalar/Reassociate.cpp
@@ -530,7 +530,13 @@ Value *Reassociate::RemoveFactorFromExpression(Value *V, Value *Factor) {
     return 0;
   }
   
-  if (Factors.size() == 1) return Factors[0].Op;
+  // If this was just a single multiply, remove the multiply and return the only
+  // remaining operand.
+  if (Factors.size() == 1) {
+    ValueRankMap.erase(BO);
+    BO->eraseFromParent();
+    return Factors[0].Op;
+  }
   
   RewriteExprTree(BO, Factors);
   return BO;