Test iriwv7

PPC iriwv7 (PPCIriwSeven)
"iriw, dependencies"
{
P0:r4=x ;
          P1:r5=y ;
P2:r4=x ; P2:r5=y ;
P3:r4=x ; P3:r5=y ;
x=z ; y=z ; z = z ;
}

P0          |P1          |P2           |P3           ;
ld r5,0(r4) |ld r4,0(r5) |std r5,0(r4) |std r4,0(r5) ;
ld r1,0(r5) |ld r1,0(r4) |             |             ;
exists(0:r5=y /\ 0:r1=z /\ 1:r4=x /\ 1:r1=z)