Test m6s

PPC m6s (PPCMSixSync)
"hexa, write-to_read causality, boehm adve PLDI'08 (Fig 5.)"
{
P0:r5=x;
P1:r5=x; P1:r6=y;
P2:r5=x; P2:r6=y;
P0:r1=1; P1:r1=1;
P3:r2=2; P3:r6=y;
} 
      P0    |       P1    |   P2         |P3          ;
stw r1,0,r5 | lwz r2,0,r5 | lwz r2,0,r6  |stw r2,0(r6);
            | sync        | sync         |            ;
            | stw r1,0,r6 | lwz r1,0,r5  |            ;

locations [x;y;]
~exists (1:r2=1 /\ 2:r2=2 /\ 2:r1=0 /\ y=2)