Test CoWR2

PPC CoWR2
(* Violation of coherence by ppcmem *)
{
x=z;
%t0=t; %x0=x;
%x1=x; %t1=t;
}
 P0             | P1             ;
 std %t0,0(%x0) | ld r1,0(%x1)   ;
                | ld r2,0(%x1)   ;
                | li r3,1        ;
                | stw r3,0(r2)   ;
                | lwz r4,0(%t1)  ;

exists (t=1 /\ 1:r4=0)