diff --git a/llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp b/llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp
--- a/llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp
@@ -831,6 +831,13 @@
     if (SubLoopsSize != 1)
       return false;
 
+    // If the Loop does not have an exit block, cannot perform unroll and jam
+    if (!L->getExitBlock()) {
+      LLVM_DEBUG(dbgs() << "Won't unroll-and-jam; Loop does not have an exit "
+                           "block\n");
+      return false;
+    }
+
     L = L->getSubLoops()[0];
   } while (L);