From 2ffa47b6bf5e98f887a45fd3a51452d4f3b67c2d Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Sat, 11 Dec 2004 17:00:14 +0000
Subject: [PATCH] Only cound if we actually made a change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18800 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/IPO/IPConstantPropagation.cpp | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/lib/Transforms/IPO/IPConstantPropagation.cpp b/lib/Transforms/IPO/IPConstantPropagation.cpp
index 99ad8445b15..65d507798b7 100644
--- a/lib/Transforms/IPO/IPConstantPropagation.cpp
+++ b/lib/Transforms/IPO/IPConstantPropagation.cpp
@@ -180,9 +180,12 @@ bool IPCP::PropagateConstantReturn(Function &F) {
   if (ReplacedAllUsers && F.hasInternalLinkage() && !isa<UndefValue>(RetVal)) {
     Value *RV = UndefValue::get(RetVal->getType());
     for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
-      if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator()))
-        RI->setOperand(0, RV);
-    MadeChange = true;
+      if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
+        if (RI->getOperand(0) != RV) {
+          RI->setOperand(0, RV);
+          MadeChange = true;
+        }
+      }
   }
 
   if (MadeChange) ++NumReturnValProped;