Test R+twice

PPC R+twice

{0:r2=x; 0:r4=y; 1:r2=y; 1:r4=x; 2:r2=x; 2:r4=y; 3:r2=y; 3:r4=x;}

 P0           | P1           | P2           | P3           ;
 li r1,1      | li r1,2      | li r1,3      | li r1,4      ;
 stw r1,0(r2) | stw r1,0(r2) | stw r1,0(r2) | stw r1,0(r2) ;
 li r3,1      | lwz r3,0(r4) | li r3,1      | lwz r3,0(r4) ;
 stw r3,0(r4) |              | stw r3,0(r4) |              ;
 lwz r5,0(r4) |              | lwz r5,0(r4) |              ;

Observed
    0:r5=4; 1:r3=3; 2:r5=2; 3:r3=0;