[Bug fortran/86100] Spurious error with -fcheck=bounds and allocatable class(*) array components

[Bug fortran/86100] Spurious error with -fcheck=bounds and allocatable class(*) array components

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86100

anlauf at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |anlauf at gcc dot gnu.org

--- Comment #2 from anlauf at gcc dot gnu.org ---
The problem seems to generally occur for class components of derived types.

program p
  implicit none
  type t
     integer :: i = 0
  end type t
  type any_matrix
     class(t), allocatable :: m(:,:)
  end type any_matrix
  type(any_matrix) :: a, b
  allocate(a%m(3,4))
  call foo ()
contains
  subroutine foo ()
    b = a      ! Array bound mismatch for dimension 1 of array '<<unknown>>'
(12/3)
    !b%m = a%m ! no runtime error with -fcheck=bounds
  end subroutine foo
end

This fails as indicated.

Note that 12=3*4 is the total size of the array, and 3 is the size of the
first dimension, which - along with the '<<unknown>>' - points to
gfc_copy_class_to_class:

          from_len = gfc_conv_descriptor_size (from_data, 1);
          from_len = fold_convert (TREE_TYPE (orig_nelems), from_len);
          tmp = fold_build2_loc (input_location, NE_EXPR,
                                  logical_type_node, from_len, orig_nelems);
          msg = xasprintf ("Array bound mismatch for dimension %d "
                           "of array '%s' (%%ld/%%ld)",
                           1, name);

          gfc_trans_runtime_check (true, false, tmp, &body,
                                   &gfc_current_locus, msg,
                             fold_convert (long_integer_type_node,
orig_nelems),
                               fold_convert (long_integer_type_node,
from_len));

So we compare dimension 1 and the full size of the rhs?
Shouldn't we compare lhs and rhs shapes?

[Bug fortran/86100] Spurious error with -fcheck=bounds and allocatable class(*) array components

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86100

--- Comment #3 from anlauf at gcc dot gnu.org ---
The code fragment in comment#2 was added in r7-3760-g92c5266bbd5378.

[Bug fortran/86100] Spurious error with -fcheck=bounds and allocatable class(*) array components

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86100

anlauf at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |anlauf at gcc dot gnu.org
           Keywords|                            |wrong-code

--- Comment #4 from anlauf at gcc dot gnu.org ---
Submitted: https://gcc.gnu.org/pipermail/fortran/2024-May/060512.html

[Bug fortran/86100] Spurious error with -fcheck=bounds and allocatable class(*) array components

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86100

--- Comment #5 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Harald Anlauf <anlauf@gcc.gnu.org>:

https://gcc.gnu.org/g:93765736815a049e14d985b758a213cfe60c1e1c

commit r15-827-g93765736815a049e14d985b758a213cfe60c1e1c
Author: Harald Anlauf <anlauf@gmx.de>
Date:   Mon May 13 22:06:33 2024 +0200

    Fortran: fix bounds check for assignment, class component [PR86100]

    gcc/fortran/ChangeLog:

            PR fortran/86100
            * trans-array.cc (gfc_conv_ss_startstride): Use abridged_ref_name
            to generate a more user-friendly name for bounds-check messages.
            * trans-expr.cc (gfc_copy_class_to_class): Fix bounds check for
            rank>1 by looping over the dimensions.

    gcc/testsuite/ChangeLog:

            PR fortran/86100
            * gfortran.dg/bounds_check_25.f90: New test.

[Bug fortran/86100] Spurious error with -fcheck=bounds and allocatable class(*) array components

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86100

--- Comment #6 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-14 branch has been updated by Harald Anlauf
<anlauf@gcc.gnu.org>:

https://gcc.gnu.org/g:b0b21d5bdfbc7d417b70010a11354b44968bb184

commit r14-10244-gb0b21d5bdfbc7d417b70010a11354b44968bb184
Author: Harald Anlauf <anlauf@gmx.de>
Date:   Mon May 13 22:06:33 2024 +0200

    Fortran: fix bounds check for assignment, class component [PR86100]

    gcc/fortran/ChangeLog:

            PR fortran/86100
            * trans-array.cc (gfc_conv_ss_startstride): Use abridged_ref_name
            to generate a more user-friendly name for bounds-check messages.
            * trans-expr.cc (gfc_copy_class_to_class): Fix bounds check for
            rank>1 by looping over the dimensions.

    gcc/testsuite/ChangeLog:

            PR fortran/86100
            * gfortran.dg/bounds_check_25.f90: New test.

    (cherry picked from commit 93765736815a049e14d985b758a213cfe60c1e1c)

[Bug fortran/86100] Spurious error with -fcheck=bounds and allocatable class(*) array components

[anlauf at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86100

anlauf at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
   Target Milestone|---                         |14.2
             Status|NEW                         |RESOLVED

--- Comment #7 from anlauf at gcc dot gnu.org ---
Fixed on mainline for gcc-15, and backported to 14-branch.  Closing.

Thanks for the report, and sorry that it took so long to fix.