Test m1s

PPC m1s  (PPCMOneSync)
"plain iriw, sync barriers"
{
P0:r4=x ; P0:r5=y ;
P1:r4=x ; P1:r5=y ;
P2:r4=x ; P3:r5=y ;
P2:r1=1 ; P3:r2=2 ;
}

P0           |P1           |P2           |P3           ;
lwz r1,0(r4) |lwz r2,0(r5) |stw r1,0(r4) |stw r2,0(r5) ;
sync         |sync         |             |             ;
lwz r2,0(r5) |lwz r1,0(r4) |             |             ;
~exists(0:r1=1 /\ 0:r2=0 /\ 1:r1=0 /\ 1:r2=2)