Allow NULL LoopPassManager argument in UnrollLoop. PR12734.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156358 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Utils/LoopUnrollRuntime.cpp b/lib/Transforms/Utils/LoopUnrollRuntime.cpp
index 3aa6bef..7672726 100644
--- a/lib/Transforms/Utils/LoopUnrollRuntime.cpp
+++ b/lib/Transforms/Utils/LoopUnrollRuntime.cpp
@@ -237,6 +237,8 @@
 
   // Use Scalar Evolution to compute the trip count.  This allows more
   // loops to be unrolled than relying on induction var simplification
+  if (!LPM)
+    return false;
   ScalarEvolution *SE = LPM->getAnalysisIfAvailable<ScalarEvolution>();
   if (SE == 0)
     return false;