Test ARMv8-csel-po

AArch64 ARMv8-csel-po

(* Final load on P0 does no depend on CSEL output *)
{
0:X7=x; 0:X8=y; 0:X9=u;
int *0:X2;
1:X7=x; 1:X8=y;
}
  P0              |  P1         ;
 LDR W1,[X7]      | MOV W0,#1   ;
 CMP W1,#0        | STR W0,[X8] ;
 CSEL X2,X8,X9,NE | DMB ST      ;
 LDR W3,[X8]      | MOV W2,#1   ;
                  | STR W2,[X7] ;
exists (0:X1=1 /\ 0:X3=0)