Test LB+lwsyncs

PPC LB+lwsyncs
"LwSyncdRW Rfe LwSyncdRW Rfe"
Cycle=Rfe LwSyncdRW 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       | lwsync       ;
 li r3,1      | li r3,1      ;
 stw r3,0(r4) | stw r3,0(r4) ;
exists
(0:r1=1 /\ 1:r1=1)