C WRC+poonceonces+Once

  (*
   * Result: Sometimes
   *
   * This litmus test is an extension of the message-passing pattern,
   * where the first write is moved to a separate process.  Note that this
   * test has no ordering at all.
   *)

  {}
  
  P0(int *x)
  {
  	WRITE_ONCE(*x, 1);
  }
  
  P1(int *x, int *y)
  {
  	int r0;
  
  	r0 = READ_ONCE(*x);
  	WRITE_ONCE(*y, 1);
  }
  
  P2(int *x, int *y)
  {
  	int r0;
  	int r1;
  
  	r0 = READ_ONCE(*y);
  	r1 = READ_ONCE(*x);
  }
  
  exists (1:r0=1 /\ 2:r0=1 /\ 2:r1=0)