[Bug fortran/51260] PARAMETER array with constructor initializer: Compile-time simplify single element access

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51260

--- Comment #5 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
The dump for the test in comment 0 is

MAIN__ ()
{
  integer(kind=4) i;
  static integer(kind=4) is[10000] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, ...,
  9989, 9990, 9991, 9992, 9993, 9994, 9995, 9996, 9997, 9998, 9999, 10000};

  {
    struct __st_parameter_dt dt_parm.0;

    dt_parm.0.common.filename = &"pr51260.f90"[1]{lb: 1 sz: 1};
    dt_parm.0.common.line = 2;
    dt_parm.0.common.flags = 128;
    dt_parm.0.common.unit = 6;
    _gfortran_st_write (&dt_parm.0);
    _gfortran_transfer_integer_write (&dt_parm.0, &is[0], 4);
    _gfortran_st_write_done (&dt_parm.0);
  }
}


__attribute__((externally_visible))
main (integer(kind=4) argc, character(kind=1) * * argv)
{
  static integer(kind=4) options.1[7] = {68, 8191, 0, 1, 1, 0, 31};

  _gfortran_set_args (argc, argv);
  _gfortran_set_options (7, &options.1[0]);
  MAIN__ ();
  return 0;
}