Index: llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp
===================================================================
--- llvm/lib/Transforms/Utils/LoopUnrollAndJam.cpp
+++ 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);
 
Index: llvm/test/Transforms/LoopUnrollAndJam/no_exit_block.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/LoopUnrollAndJam/no_exit_block.ll
@@ -0,0 +1,126 @@
+; RUN: opt -debug-only=loop-unroll-and-jam -passes="default<O3>" -disable-output -enable-unroll-and-jam -allow-unroll-and-jam -unroll-and-jam-count=8 %s 2>&1 | FileCheck %s
+
+;CHECK: Loop Unroll and Jam: F[h] Loop %bb8
+;CHECK: Won't unroll-and-jam; Loop does not have an exit block
+
+target datalayout = "E-m:e-i1:8:16-i8:8:16-i64:64-f128:64-v128:64-a:8:16-n32:64"
+target triple = "s390x-ibm-linux"
+
+@a = external dso_local global i16, align 2
+@e = external dso_local global i32, align 4
+@f = external dso_local global i16, align 2
+@b = external dso_local global i16, align 2
+@c = external dso_local global i64, align 8
+
+define dso_local i16 @g() #0 {
+bb:
+  %i = load i16, i16* @a, align 2
+  ret i16 %i
+}
+
+define dso_local void @h() #1 {
+bb:
+  %i = alloca i32, align 4
+  %i1 = alloca i32, align 4
+  %i2 = alloca [0 x i32], align 4
+  %i3 = alloca i32*, align 8
+  %i4 = alloca i32*, align 8
+  store i32 4, i32* @e, align 4
+  br label %bb5
+
+bb5:                                              ; preds = %bb47, %bb
+  %i6 = load i32, i32* @e, align 4
+  %i7 = icmp ne i32 %i6, 0
+  br i1 %i7, label %bb8, label %bb50
+
+bb8:                                              ; preds = %bb5
+  %i9 = bitcast [0 x i32]* %i2 to i8*
+  call void @llvm.lifetime.start.p0i8(i64 0, i8* %i9) #4
+  store i16 0, i16* @f, align 2
+  br label %bb10
+
+bb10:                                             ; preds = %bb43, %bb8
+  %i11 = load i16, i16* @f, align 2
+  %i12 = sext i16 %i11 to i32
+  %i13 = icmp sle i32 %i12, 7
+  br i1 %i13, label %bb14, label %bb47
+
+bb14:                                             ; preds = %bb10
+  store i32* %i, i32** %i3, align 8
+  %i15 = load i16, i16* @b, align 2
+  %i16 = sext i16 %i15 to i32
+  %i17 = icmp sgt i32 %i16, 0
+  %i18 = zext i1 %i17 to i32
+  %i19 = load i32*, i32** %i3, align 8
+  %i20 = load i32, i32* %i19, align 4
+  %i21 = and i32 %i20, %i18
+  store i32 %i21, i32* %i19, align 4
+  %i22 = load i32, i32* %i1, align 4
+  %i23 = icmp ne i32 %i22, 0
+  br i1 %i23, label %bb24, label %bb32
+
+bb24:                                             ; preds = %bb14
+  store i32* %i1, i32** %i4, align 8
+  %i25 = load i32*, i32** %i3, align 8
+  %i26 = load i32, i32* %i25, align 4
+  %i27 = icmp ne i32 %i26, 0
+  br i1 %i27, label %bb28, label %bb39
+
+bb28:                                             ; preds = %bb24
+  %i29 = getelementptr inbounds [0 x i32], [0 x i32]* %i2, i64 0, i64 1
+  %i30 = load i32, i32* %i29, align 4
+  %i31 = load i32*, i32** %i4, align 8
+  store i32 %i30, i32* %i31, align 4
+  br label %bb39
+
+bb32:                                             ; preds = %bb35, %bb14
+  %i33 = load i64, i64* @c, align 8
+  %i34 = icmp ne i64 %i33, 0
+  br i1 %i34, label %bb35, label %bb39
+
+bb35:                                             ; preds = %bb32
+  %i36 = call signext i16 @g()
+  %i37 = sext i16 %i36 to i32
+  %i38 = load i32*, i32** %i3, align 8
+  store i32 %i37, i32* %i38, align 4
+  store i64 0, i64* @c, align 8
+  br label %bb32
+
+bb39:                                             ; preds = %bb32, %bb28, %bb24
+  %i40 = load i32*, i32** %i3, align 8
+  %i41 = load i32, i32* %i40, align 4
+  %i42 = icmp ne i32 %i41, 0
+  br i1 %i42, label %bb43, label %bb46
+
+bb43:                                             ; preds = %bb39
+  %i44 = load i16, i16* @f, align 2
+  %i45 = add i16 %i44, 1
+  store i16 %i45, i16* @f, align 2
+  br label %bb10
+
+bb46:                                             ; preds = %bb46, %bb39
+  br label %bb46
+
+bb47:                                             ; preds = %bb10
+  %i48 = load i32, i32* @e, align 4
+  %i49 = add nsw i32 %i48, -1
+  store i32 %i49, i32* @e, align 4
+  br label %bb5
+
+bb50:                                             ; preds = %bb5
+  ret void
+}
+
+; Function Attrs: argmemonly nofree nosync nounwind willreturn
+declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture) #2
+
+define dso_local void @main() #3 {
+bb:
+  ret void
+}
+
+attributes #0 = { "no-jump-tables"="false" }
+attributes #1 = { "target-features"="+transactional-execution,+vector,+vector-enhancements-1,+vector-enhancements-2" }
+attributes #2 = { argmemonly nofree nosync nounwind willreturn }
+attributes #3 = { "use-soft-float"="false" }
+attributes #4 = { nounwind }