1C IRIW+poonceonces+OnceOnce
2
3{}
4
5P0(int *x)
6{
7	WRITE_ONCE(*x, 1);
8}
9
10P1(int *x, int *y)
11{
12	int r0;
13	int r1;
14
15	r0 = READ_ONCE(*x);
16	r1 = READ_ONCE(*y);
17}
18
19P2(int *y)
20{
21	WRITE_ONCE(*y, 1);
22}
23
24P3(int *x, int *y)
25{
26	int r0;
27	int r1;
28
29	r0 = READ_ONCE(*y);
30	r1 = READ_ONCE(*x);
31}
32
33exists (1:r0=1 /\ 1:r1=0 /\ 3:r0=1 /\ 3:r1=0)
34