fix a crasher in disabled code (on variable stride loops)


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126125 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/LoopIdiomRecognize.cpp b/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
index 568a143..f8ce214 100644
--- a/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
+++ b/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
@@ -281,7 +281,7 @@
     // TODO: Could also handle negative stride here someday, that will require
     // the validity check in mayLoopAccessLocation to be updated though.
     // Enable this to print exact negative strides.
-    if (0 && StoreSize == -Stride->getValue()->getValue()) {
+    if (0 && Stride && StoreSize == -Stride->getValue()->getValue()) {
       dbgs() << "NEGATIVE STRIDE: " << *SI << "\n";
       dbgs() << "BB: " << *SI->getParent();
     }