1C cmpxchg-fail-unordered-2
 2
 3(*
 4 * Result: Sometimes
 5 *
 6 * Demonstrate that a failing cmpxchg() operation does not act as either
 7 * an acquire release operation.  (In contrast, a successful cmpxchg()
 8 * does act as both an acquire and a release operation.)
 9 *)
10
11{}
12
13P0(int *x, int *y)
14{
15	int r1;
16
17	WRITE_ONCE(*x, 1);
18	r1 = cmpxchg(y, 0, 1);
19}
20
21P1(int *x, int *y)
22{
23	int r1;
24	int r2;
25
26	r1 = cmpxchg(y, 0, 1);
27	r2 = READ_ONCE(*x);
28}
29
30exists (0:r1=0 /\ 1:r1=1 /\ 1:r2=0)