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C IRIW+fencembonceonces+OnceOnce
(*
* Result: Never
*
* Test of independent reads from independent writes with smp_mb()
* between each pairs of reads. In other words, is smp_mb() sufficient to
* cause two different reading processes to agree on the order of a pair
* of writes, where each write is to a different variable by a different
* process? This litmus test exercises LKMM's "propagation" rule.
*)
{}
P0(int *x)
{
WRITE_ONCE(*x, 1);
}
P1(int *x, int *y)
{
int r0;
int r1;
r0 = READ_ONCE(*x);
smp_mb();
r1 = READ_ONCE(*y);
}
P2(int *y)
{
WRITE_ONCE(*y, 1);
}
P3(int *x, int *y)
{
int r0;
int r1;
r0 = READ_ONCE(*y);
smp_mb();
r1 = READ_ONCE(*x);
}
exists (1:r0=1 /\ 1:r1=0 /\ 3:r0=1 /\ 3:r1=0)
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