[Bug fortran/71027] -fsanitize=address catches out of bounds access on assumed size array only with -O0

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71027

Dominique d'Humieres <dominiq at lps dot ens.fr> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
   Last reconfirmed|                            |2016-05-09
     Ever confirmed|0                           |1

--- Comment #1 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
IMO your expectation is invalid:

[Book15] f90/bug% gfc pr71027.f90 -Og -fdump-tree-optimized
[Book15] f90/bug% cat pr71027.f90.211t.optimized 

;; Function main (main, funcdef_no=2, decl_uid=3429, cgraph_uid=2,
symbol_order=2) (executed once)

__attribute__((externally_visible))
main (integer(kind=4) argc, character(kind=1) * * argv)
{
  static integer(kind=4) options.0[9] = {68, 1023, 0, 0, 1, 1, 0, 0, 31};

  <bb 2>:
  _gfortran_set_args (argc_2(D), argv_3(D));
  _gfortran_set_options (9, &options.0[0]);
  return 0;

}

i.e., the subroutine sub is optimized away. If you do something such as

      subroutine sub(vv)
      dimension vv(*)
      x=vv(20) ! out of bounds access
      vv(1)=x
      end subroutine

then -fsanitize=address catches the invalid address.