Test LB+lwsync+po

PPC LB+lwsync+po
"LwSyncdRW Rfe PodRW Rfe"
Cycle=Rfe PodRW Rfe LwSyncdRW
{
0:r2=x; 0:r4=y;
1:r2=y; 1:r4=x;
}
 P0           | P1           ;
 lwz r1,0(r2) | lwz r1,0(r2) ;
 lwsync       | li r3,1      ;
 li r3,1      | stw r3,0(r4) ;
 stw r3,0(r4) |              ;
exists
(0:r1=1 /\ 1:r1=1)