Test iriwdepv1

PPC iriwdepv1 (PPCIriwDepOne)
"iriw, dependencies + two barriers on loads"
{
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) ;
lwsync       |lwsync       |             |             ;
ld  r1,0(r5) |ld  r1,0(r4) |             |             ;
exists(0:r5=y /\ 0:r1=z /\ 1:r4=x /\ 1:r1=z)