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C dep+plain
(*
* Result: Never
*
* This litmus test demonstrates that in LKMM, plain accesses
* carry dependencies much like accesses to registers:
* The data stored to *z1 and *z2 by P0() originates from P0()'s
* READ_ONCE(), and therefore using that data to compute the
* conditional of P0()'s if-statement creates a control dependency
* from that READ_ONCE() to P0()'s WRITE_ONCE().
*)
{}
P0(int *x, int *y, int *z1, int *z2)
{
int a = READ_ONCE(*x);
*z1 = a;
*z2 = *z1;
if (*z2 == 1)
WRITE_ONCE(*y, 1);
}
P1(int *x, int *y)
{
int r = smp_load_acquire(y);
smp_store_release(x, r);
}
exists (x=1 /\ y=1)
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