From 50f5490842d501e269a4c6085d0d132cae0d31f8 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Wed, 29 Jun 2005 17:41:25 +0000
Subject: [PATCH] Don't crash on a query where the block is not in any loop. 
 Thanks to Sameer D. Sahasrabuddhe for pointing this out!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22314 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Analysis/LoopInfo.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/llvm/Analysis/LoopInfo.h b/include/llvm/Analysis/LoopInfo.h
index 5e818bcbe19..9357d8fb6ea 100644
--- a/include/llvm/Analysis/LoopInfo.h
+++ b/include/llvm/Analysis/LoopInfo.h
@@ -250,7 +250,8 @@ public:
 
   // isLoopHeader - True if the block is a loop header node
   bool isLoopHeader(BasicBlock *BB) const {
-    return getLoopFor(BB)->getHeader() == BB;
+    const Loop *L = getLoopFor(BB);
+    return L && L->getHeader() == BB;
   }
 
   /// runOnFunction - Calculate the natural loop information.