From 253449db20f86b655852a397245ba16ff262452f Mon Sep 17 00:00:00 2001
From: Shuxin Yang <shuxin.llvm@gmail.com>
Date: Thu, 10 Jan 2013 23:32:01 +0000
Subject: PR14904: Segmentation fault running pass 'Recognize loop idioms'

The root cause is mistakenly taking for granted that
    "dyn_cast<Instruction>(a-Value)"
return a non-NULL instruction.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172145 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Scalar/LoopIdiomRecognize.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'lib/Transforms')

diff --git a/lib/Transforms/Scalar/LoopIdiomRecognize.cpp b/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
index c4f90125ac..8258719a02 100644
--- a/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
+++ b/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
@@ -407,7 +407,7 @@ bool NclPopcountRecognize::detectIdiom(Instruction *&CntInst,
 
   // step 2: detect instructions corresponding to "x2 = x1 & (x1 - 1)"
   {
-    if (DefX2->getOpcode() != Instruction::And)
+    if (!DefX2 || DefX2->getOpcode() != Instruction::And)
       return false;
 
     BinaryOperator *SubOneOp;
-- 
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