Test safe246

PPC safe246
"SyncdWR Fre SyncdWW Rfe DpsW Rfe SyncdRW Wse"
Cycle=SyncdWR Fre SyncdWW Rfe DpsW Rfe SyncdRW Wse
Relax=
Safe=Fre Wse SyncdWR DpsW ACSyncdRW BCSyncdWW
{
0:r2=x; 0:r4=y;
1:r2=y;
2:r2=y; 2:r4=z;
3:r2=z; 3:r4=x;
}
 P0           | P1            | P2           | P3           ;
 li r1,1      | lwz r1,0(r2)  | lwz r1,0(r2) | li r1,2      ;
 stw r1,0(r2) | xor r3,r1,r1  | sync         | stw r1,0(r2) ;
 sync         | li r4,2       | li r3,1      | sync         ;
 li r3,1      | stwx r4,r3,r2 | stw r3,0(r4) | lwz r3,0(r4) ;
 stw r3,0(r4) |               |              |              ;
exists
(y=2 /\ z=2 /\ 1:r1=1 /\ 2:r1=2 /\ 3:r3=0)