Test LxSxd

AArch64 LxSxd
{
  0:X1=x;
  0:X3=y;
}
  P0              ;
  LDXR W0,[X1]    ;
  MOV W2,#1       ;
  STXR W4,W2,[X3] ;
Observed
    y=1; 0:X4=0;