Test ARMv8-pred-addr

AArch64 ARMv8-pred-addr

(* In ARMv8, an address dependency where the dataflow pathway involves
   only the control of a predicated instruction or conditional branch
   doesn't count as an address dependency at all.

   The following test should be allowed, because the CPU can speculate
   the value of 1:r2 and then perform the read of y before the read of x.
*)

{
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   ;
 CBNZ W1,Lelse | STR W0,[X8] ;
 ADD X2,X9,#0  | DMB ST      ;
 B Lexit       | MOV W2,#1   ;
Lelse:         | STR W2,[X7] ;
 ADD X2,X8,#0  |             ;
Lexit:         |             ;
 LDR W3,[X2]   |             ;
locations [0:X2;]
exists (0:X1=1 /\ 0:X3=0)