Test iriwv2

PPC iriwv2 (PPCIriwTwo)
"iriw, local dependencies for reads"
{
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) ;
xor r3,r1,r1 |xor r3,r2,r2 |             |             ;
lwzx r2,r3,r5|lwzx r1,r3,r4|             |             ;
exists(0:r1=1 /\ 0:r2=0 /\ 1:r1=0 /\ 1:r2=2)