C S+poonceonces

{}

P0(int *x, int *y)
{
	WRITE_ONCE(*x, 2);
	WRITE_ONCE(*y, 1);
}

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

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

exists (x=2 /\ 1:r0=1)