1 files changed, 38 insertions, 0 deletions
diff --git a/test/Transforms/Reassociate/no-op.ll b/test/Transforms/Reassociate/no-op.ll
new file mode 100644
index 0000000..0444cf0
--- /dev/null
+++ b/test/Transforms/Reassociate/no-op.ll
@@ -0,0 +1,38 @@
+; RUN: opt < %s -reassociate -S | FileCheck %s
+
+; When there is nothing to do, or not much to do, check that reassociate leaves
+; things alone.
+
+declare void @use(i32)
+
+define void @test1(i32 %a, i32 %b) {
+; Shouldn't change or move any of the add instructions.  Should commute but
+; otherwise not change or move any of the mul instructions.
+; CHECK: @test1
+  %a0 = add nsw i32 %a, 1
+; CHECK-NEXT: %a0 = add nsw i32 %a, 1
+  %m0 = mul nsw i32 3, %a
+; CHECK-NEXT: %m0 = mul nsw i32 %a, 3
+  %a1 = add nsw i32 %a0, %b
+; CHECK-NEXT: %a1 = add nsw i32 %a0, %b
+  %m1 = mul nsw i32 %b, %m0
+; CHECK-NEXT: %m1 = mul nsw i32 %m0, %b
+  call void @use(i32 %a1)
+; CHECK-NEXT: call void @use
+  call void @use(i32 %m1)
+  ret void
+}
+
+define void @test2(i32 %a, i32 %b, i32 %c, i32 %d) {
+; The initial add doesn't change so should not lose the nsw flag.
+; CHECK: @test2
+  %a0 = add nsw i32 %b, %a
+; CHECK-NEXT: %a0 = add nsw i32 %b, %a
+  %a1 = add nsw i32 %a0, %d
+; CHECK-NEXT: %a1 = add i32 %a0, %c
+  %a2 = add nsw i32 %a1, %c
+; CHECK-NEXT: %a2 = add i32 %a1, %d
+  call void @use(i32 %a2)
+; CHECK-NEXT: call void @use
+  ret void
+}