1; RUN: opt -S -basic-aa -dse < %s | FileCheck %s
2
3; We conservative choose to prevent dead store elimination
4; across release or stronger fences.  It's not required
5; (since the must still be a race on %addd.i), but
6; it is conservatively correct.  A legal optimization
7; could hoist the second store above the fence, and then
8; DSE one of them.
9define void @test1(i32* %addr.i) {
10; CHECK-LABEL: @test1
11; CHECK: store i32 5
12; CHECK: fence
13; CHECK: store i32 5
14; CHECK: ret
15  store i32 5, i32* %addr.i, align 4
16  fence release
17  store i32 5, i32* %addr.i, align 4
18  ret void
19}
20
21; Same as previous, but with different values.  If we ever optimize
22; this more aggressively, this allows us to check that the correct
23; store is retained (the 'i32 1' store in this case)
24define void @test1b(i32* %addr.i) {
25; CHECK-LABEL: @test1b
26; CHECK: store i32 42
27; CHECK: fence release
28; CHECK: store i32 1
29; CHECK: ret
30  store i32 42, i32* %addr.i, align 4
31  fence release
32  store i32 1, i32* %addr.i, align 4
33  ret void
34}
35
36; We *could* DSE across this fence, but don't.  No other thread can
37; observe the order of the acquire fence and the store.
38define void @test2(i32* %addr.i) {
39; CHECK-LABEL: @test2
40; CHECK: store
41; CHECK: fence
42; CHECK: store
43; CHECK: ret
44  store i32 5, i32* %addr.i, align 4
45  fence acquire
46  store i32 5, i32* %addr.i, align 4
47  ret void
48}
49