[Bug rtl-optimization/69206] New: testsuite/gcc.c-torture/execute/alias-2.c fails on aarch64-linux-gnu at -O1 and above

["pinskia at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69206

            Bug ID: 69206
           Summary: testsuite/gcc.c-torture/execute/alias-2.c fails on
                    aarch64-linux-gnu at -O1 and above
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---

The tree level looks correct:

  b[off.0_2] = 1;
  a[off.0_2] = 2;
  _5 = b[off.0_2];
  if (_5 != 2)
    goto <bb 3>;
  else
    goto <bb 4>;

  <bb 3>:
  __builtin_abort ();

But the final output is not:
main:
        stp     x29, x30, [sp, -16]!
        add     x29, sp, 0
        adrp    x0, off
        ldrsw   x2, [x0, #:lo12:off]
        adrp    x1, b
        adrp    x0, .LANCHOR0
        add     x1, x1, :lo12:b
        mov     w4, 1
        add     x0, x0, :lo12:.LANCHOR0
        str     w4, [x1, x2, lsl 2]
        mov     w3, 2
        str     w3, [x0, x2, lsl 2]
        bl      abort