From 1fb5630474d261eca0b4de9c79279b9c9e42a444 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Sun, 15 Nov 2009 19:57:43 +0000
Subject: [PATCH] fix a bug handling 'not x' when x is undef.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@88864 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Scalar/JumpThreading.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/Transforms/Scalar/JumpThreading.cpp b/lib/Transforms/Scalar/JumpThreading.cpp
index d5ce86aca0c..de4c118b69d 100644
--- a/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/lib/Transforms/Scalar/JumpThreading.cpp
@@ -350,8 +350,9 @@ ComputeValueKnownInPredecessors(Value *V, BasicBlock *BB,PredValueInfo &Result){
 
       // Invert the known values.
       for (unsigned i = 0, e = Result.size(); i != e; ++i)
-        Result[i].first =
-          cast<ConstantInt>(ConstantExpr::getNot(Result[i].first));
+        if (Result[i].first)
+          Result[i].first =
+            cast<ConstantInt>(ConstantExpr::getNot(Result[i].first));
       return true;
     }
   }