From e7c90967b17286b0e8fe21fcbfb9cf898b6e7a96 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Tue, 10 Nov 2009 01:19:06 +0000
Subject: [PATCH] don't invalidate PN, rewrite of this code is in progress
 anyway.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86639 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Scalar/JumpThreading.cpp | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp
index 46d40ef5d15..7a7f407b96b 100644
--- a/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/lib/Transforms/Scalar/JumpThreading.cpp
@@ -223,10 +223,11 @@ static void RemovePredecessorAndSimplify(BasicBlock *BB, BasicBlock *Pred,
       U = PNV;
       
       // See if we can simplify it.
-      if (Value *V = SimplifyInstruction(User, TD)) {
-        User->replaceAllUsesWith(V);
-        User->eraseFromParent();
-      }
+      if (User != PN)
+        if (Value *V = SimplifyInstruction(User, TD)) {
+          User->replaceAllUsesWith(V);
+          User->eraseFromParent();
+        }
     }
     
     PN->replaceAllUsesWith(PNV);