LoopUnroll: always check for NULL LoopPassManager

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158007 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Utils/LoopUnroll.cpp b/lib/Transforms/Utils/LoopUnroll.cpp
index 0780b13..2023750 100644
--- a/lib/Transforms/Utils/LoopUnroll.cpp
+++ b/lib/Transforms/Utils/LoopUnroll.cpp
@@ -95,9 +95,11 @@
   // Erase basic block from the function...
 
   // ScalarEvolution holds references to loop exit blocks.
-  if (ScalarEvolution *SE = LPM->getAnalysisIfAvailable<ScalarEvolution>()) {
-    if (Loop *L = LI->getLoopFor(BB))
-      SE->forgetLoop(L);
+  if (LPM) {
+    if (ScalarEvolution *SE = LPM->getAnalysisIfAvailable<ScalarEvolution>()) {
+      if (Loop *L = LI->getLoopFor(BB))
+        SE->forgetLoop(L);
+    }
   }
   LI->removeBlock(BB);
   BB->eraseFromParent();