1; RUN: llc -mtriple=armv7-apple-ios6.0 -mcpu=swift < %s | FileCheck %s
2; RUN: llc -mtriple=armv7-apple-ios6.0 < %s | FileCheck %s --check-prefix=CHECK-STRICT-ATOMIC
3
4; Release operations only need the store barrier provided by a "dmb ishst",
5
6define void @test_store_release(i32* %p, i32 %v) {
7; CHECK-LABEL: test_store_release:
8; CHECK: dmb ishst
9; CHECK: str
10
11; CHECK-STRICT-ATOMIC-LABEL: test_store_release:
12; CHECK-STRICT-ATOMIC: dmb {{ish$}}
13  store atomic i32 %v, i32* %p release, align 4
14  ret void
15}
16
17; However, if sequential consistency is needed *something* must ensure a release
18; followed by an acquire does not get reordered. In that case a "dmb ishst" is
19; not adequate.
20define i32 @test_seq_cst(i32* %p, i32 %v) {
21; CHECK-LABEL: test_seq_cst:
22; CHECK: dmb ishst
23; CHECK: str
24; CHECK: dmb {{ish$}}
25; CHECK: ldr
26; CHECK: dmb {{ish$}}
27
28; CHECK-STRICT-ATOMIC-LABEL: test_seq_cst:
29; CHECK-STRICT-ATOMIC: dmb {{ish$}}
30; CHECK-STRICT-ATOMIC: str
31; CHECK-STRICT-ATOMIC: dmb {{ish$}}
32; CHECK-STRICT-ATOMIC: ldr
33; CHECK-STRICT-ATOMIC: dmb {{ish$}}
34
35  store atomic i32 %v, i32* %p seq_cst, align 4
36  %val = load atomic i32, i32* %p seq_cst, align 4
37  ret i32 %val
38}
39
40; Also, pure acquire operations should definitely not have an ishst barrier.
41
42define i32 @test_acq(i32* %addr) {
43; CHECK-LABEL: test_acq:
44; CHECK: ldr
45; CHECK: dmb {{ish$}}
46
47; CHECK-STRICT-ATOMIC-LABEL: test_acq:
48; CHECK-STRICT-ATOMIC: dmb {{ish$}}
49  %val = load atomic i32, i32* %addr acquire, align 4
50  ret i32 %val
51}
52