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
diff --git a/lib/Transforms/Scalar/LoopIdiomRecognize.cpp b/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
index c4f9012..8258719 100644
--- a/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
+++ b/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
@@ -407,7 +407,7 @@
// 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;