Test safe496

PPC safe496
"SyncdWW Rfe DpsW Rfe SyncdRW Rfe SyncsRR Fre"
Cycle=SyncdWW Rfe DpsW Rfe SyncdRW Rfe SyncsRR Fre
Relax=
Safe=Fre DpsW ACSyncsRR ACSyncdRW BCSyncdWW
{
0:r2=x;
1:r2=x; 1:r4=y;
2:r2=y;
3:r2=y; 3:r4=x;
}
 P0            | P1           | P2           | P3           ;
 lwz r1,0(r2)  | lwz r1,0(r2) | lwz r1,0(r2) | li r1,2      ;
 xor r3,r1,r1  | sync         | sync         | stw r1,0(r2) ;
 li r4,2       | li r3,1      | lwz r3,0(r2) | sync         ;
 stwx r4,r3,r2 | stw r3,0(r4) |              | li r3,1      ;
               |              |              | stw r3,0(r4) ;
exists
(x=2 /\ y=2 /\ 0:r1=1 /\ 1:r1=2 /\ 2:r1=1 /\ 2:r3=1)