2 files changed, 70 insertions, 1 deletions
diff --git a/test/Transforms/LoopRotate/dbgvalue.ll b/test/Transforms/LoopRotate/dbgvalue.ll
index 9461980ac0..50fc9659a8 100644
--- a/test/Transforms/LoopRotate/dbgvalue.ll
+++ b/test/Transforms/LoopRotate/dbgvalue.ll
@@ -46,7 +46,11 @@ define void @FindFreeHorzSeg(i64 %startCol, i64 %row, i64* %rowStart) {
 ; CHECK-LABEL: define void @FindFreeHorzSeg(
 ; CHECK: %dec = add
 ; CHECK-NEXT: tail call void @llvm.dbg.value
-; CHECK-NEXT: br i1 %tobool, label %for.cond, label %for.end
+; CHECK-NEXT: br i1 %tobool, label %for.cond, label %[[LOOP_EXIT:[^,]*]]
+; CHECK: [[LOOP_EXIT]]:
+; CHECK-NEXT: phi i64 [ %{{[^,]*}}, %{{[^,]*}} ]
+; CHECK-NEXT: br label %for.end
+
 
 entry:
   br label %for.cond
diff --git a/test/Transforms/LoopRotate/preserve-loop-simplify.ll b/test/Transforms/LoopRotate/preserve-loop-simplify.ll
new file mode 100644
index 0000000000..53fa02a42a
--- /dev/null
+++ b/test/Transforms/LoopRotate/preserve-loop-simplify.ll
@@ -0,0 +1,65 @@
+; RUN: opt -S -loop-rotate < %s -verify-loop-info | FileCheck %s
+;
+; Verify that LoopRotate preserves LoopSimplify form even in very peculiar loop
+; structures. We manually validate the CFG with FileCheck because currently we
+; can't cause a failure when LoopSimplify fails to be preserved.
+
+define void @PR18643() {
+; CHECK-LABEL: @PR18643(
+entry:
+  br label %outer.header
+; CHECK: br label %outer.header
+
+outer.header:
+; CHECK: outer.header:
+  br i1 undef, label %inner.header, label %outer.body
+; CHECK-NEXT: br i1 {{[^,]*}}, label %[[INNER_PREROTATE_PREHEADER:[^,]*]], label %outer.body
+
+; CHECK: [[INNER_PREROTATE_PREHEADER]]:
+; CHECK-NEXT: br i1 {{[^,]*}}, label %[[INNER_PREROTATE_PREHEADER_SPLIT_RETURN:[^,]*]], label %[[INNER_ROTATED_PREHEADER:[^,]*]]
+
+; CHECK: [[INNER_ROTATED_PREHEADER]]:
+; CHECK-NEXT: br label %inner.body
+
+inner.header:
+; Now the latch!
+; CHECK: inner.header:
+  br i1 undef, label %return, label %inner.body
+; CHECK-NEXT: br i1 {{[^,]*}}, label %[[INNER_SPLIT_RETURN:[^,]*]], label %inner.body
+
+inner.body:
+; Now the header!
+; CHECK: inner.body:
+  br i1 undef, label %outer.latch, label %inner.latch
+; CHECK-NEXT: br i1 {{[^,]*}}, label %[[INNER_SPLIT_OUTER_LATCH:[^,]*]], label %inner.header
+
+inner.latch:
+; Dead!
+  br label %inner.header
+
+outer.body:
+; CHECK: outer.body:
+  br label %outer.latch
+; CHECK-NEXT: br label %outer.latch
+
+; L2 -> L1 exit edge needs a simplified exit block.
+; CHECK: [[INNER_SPLIT_OUTER_LATCH]]:
+; CHECK-NEXT: br label %outer.latch
+
+outer.latch:
+; CHECK: outer.latch:
+  br label %outer.header
+; CHECK-NEXT: br label %outer.header
+
+; L1 -> L0 exit edge need sa simplified exit block.
+; CHECK: [[INNER_PREROTATE_PREHEADER_SPLIT_RETURN]]:
+; CHECK-NEXT: br label %return
+
+; L2 -> L0 exit edge needs a simplified exit block.
+; CHECK: [[INNER_SPLIT_RETURN]]:
+; CHECK-NEXT: br label %return
+
+return:
+; CHECK: return:
+  unreachable
+}