1 C cmpxchg-fail-unordered-1
2
3 (*
4 * Result: Sometimes
5 *
6 * Demonstrate that a failing cmpxchg() operation does not act as a
7 * full barrier. (In contrast, a successful cmpxchg() does act as a
8 * full barrier.)
9 *)
10
11 {}
12
13 P0(int *x, int *y, int *z)
14 {
15 int r0;
16 int r1;
17
18 WRITE_ONCE(*x, 1);
19 r1 = cmpxchg(z, 1, 0);
20 r0 = READ_ONCE(*y);
21 }
22
23 P1(int *x, int *y, int *z)
24 {
25 int r0;
26 int r1;
27
28 WRITE_ONCE(*y, 1);
29 r1 = cmpxchg(z, 1, 0);
30 r0 = READ_ONCE(*x);
31 }
32
33 locations[0:r1;1:r1]
34 exists (0:r0=0 /\ 1:r0=0)
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