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-rw-r--r--llvm/lib/Transforms/Scalar/LoopRotation.cpp6
-rw-r--r--llvm/test/Transforms/LoopRotate/crash.ll16
2 files changed, 21 insertions, 1 deletions
diff --git a/llvm/lib/Transforms/Scalar/LoopRotation.cpp b/llvm/lib/Transforms/Scalar/LoopRotation.cpp
index 95e15784df2..e7b1a031f84 100644
--- a/llvm/lib/Transforms/Scalar/LoopRotation.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopRotation.cpp
@@ -184,7 +184,11 @@ bool LoopRotate::rotateLoop(Loop *L) {
// Now, this loop is suitable for rotation.
BasicBlock *OrigPreheader = L->getLoopPreheader();
BasicBlock *OrigLatch = L->getLoopLatch();
- assert(OrigPreheader && OrigLatch && "Loop not in canonical form?");
+
+ // If the loop could not be converted to canonical form, it must have an
+ // indirectbr in it, just give up.
+ if (OrigPreheader == 0 || OrigLatch == 0)
+ return false;
// Anything ScalarEvolution may know about this loop or the PHI nodes
// in its header will soon be invalidated.
diff --git a/llvm/test/Transforms/LoopRotate/crash.ll b/llvm/test/Transforms/LoopRotate/crash.ll
index 9dc9862d150..16a6868f8ff 100644
--- a/llvm/test/Transforms/LoopRotate/crash.ll
+++ b/llvm/test/Transforms/LoopRotate/crash.ll
@@ -137,3 +137,19 @@ bb17: ; preds = %bb15
}
+
+
+; PR9523 - Non-canonical loop.
+define void @test7(i8* %P) nounwind {
+entry:
+ indirectbr i8* %P, [label %"3", label %"5"]
+
+"3": ; preds = %"4", %entry
+ br i1 undef, label %"5", label %"4"
+
+"4": ; preds = %"3"
+ br label %"3"
+
+"5": ; preds = %"3", %entry
+ ret void
+}
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