1 files changed, 79 insertions, 0 deletions
diff --git a/test/Transforms/LICM/atomics.ll b/test/Transforms/LICM/atomics.ll
new file mode 100644
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--- /dev/null
+++ b/test/Transforms/LICM/atomics.ll
@@ -0,0 +1,79 @@
+; RUN: opt < %s -S -basicaa -licm | FileCheck %s
+
+; Check that we can hoist unordered loads
+define i32 @test1(i32* nocapture %y) nounwind uwtable ssp {
+entry:
+  br label %loop
+
+loop:
+  %i = phi i32 [ %inc, %loop ], [ 0, %entry ]
+  %val = load atomic i32* %y unordered, align 4
+  %inc = add nsw i32 %i, 1
+  %exitcond = icmp eq i32 %inc, %val
+  br i1 %exitcond, label %end, label %loop
+
+end:
+  ret i32 %val
+; CHECK: define i32 @test1(
+; CHECK: load atomic
+; CHECK-NEXT: br label %loop
+}
+
+; Check that we don't sink/hoist monotonic loads
+; (Strictly speaking, it's not forbidden, but it's supposed to be possible to
+; use monotonic for spinlock-like constructs.)
+define i32 @test2(i32* nocapture %y) nounwind uwtable ssp {
+entry:
+  br label %loop
+
+loop:
+  %val = load atomic i32* %y monotonic, align 4
+  %exitcond = icmp ne i32 %val, 0
+  br i1 %exitcond, label %end, label %loop
+
+end:
+  ret i32 %val
+; CHECK: define i32 @test2(
+; CHECK: load atomic
+; CHECK-NEXT: %exitcond = icmp ne
+; CHECK-NEXT: br i1 %exitcond, label %end, label %loop
+}
+
+; Check that we hoist unordered around monotonic.
+; (The noalias shouldn't be necessary in theory, but LICM isn't quite that
+; smart yet.)
+define i32 @test3(i32* nocapture noalias %x, i32* nocapture %y) nounwind uwtable ssp {
+entry:
+  br label %loop
+
+loop:
+  %vala = load atomic i32* %y monotonic, align 4
+  %valb = load atomic i32* %x unordered, align 4
+  %exitcond = icmp ne i32 %vala, %valb
+  br i1 %exitcond, label %end, label %loop
+
+end:
+  ret i32 %vala
+; CHECK: define i32 @test3(
+; CHECK: load atomic i32* %x unordered
+; CHECK-NEXT: br label %loop
+}
+
+; Don't try to "sink" unordered stores yet; it is legal, but the machinery
+; isn't there.
+define i32 @test4(i32* nocapture noalias %x, i32* nocapture %y) nounwind uwtable ssp {
+entry:
+  br label %loop
+
+loop:
+  %vala = load atomic i32* %y monotonic, align 4
+  store atomic i32 %vala, i32* %x unordered, align 4
+  %exitcond = icmp ne i32 %vala, 0
+  br i1 %exitcond, label %end, label %loop
+
+end:
+  ret i32 %vala
+; CHECK: define i32 @test4(
+; CHECK: load atomic i32* %y monotonic
+; CHECK-NEXT: store atomic
+}