C LB+ctrlonceonce+mbonceonce

{}

P0(int *x, int *y)
{
	int r0;

	r0 = READ_ONCE(*x);
	if (r0)
		WRITE_ONCE(*y, 1);
}

P1(int *x, int *y)
{
	int r0;

	r0 = READ_ONCE(*y);
	smp_mb();
	WRITE_ONCE(*x, 1);
}

exists (0:r0=1 /\ 1:r0=1)