From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
	id 72E343858C35; Wed,  8 May 2024 19:26:04 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 72E343858C35
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org;
	s=default; t=1715196364;
	bh=3ec1rygUA8YXYOQuO6SqdNeZ01xNi3/oGIZcospiEKE=;
	h=From:To:Subject:Date:In-Reply-To:References:From;
	b=F+raazNhODjJRe5KgiA9it6UlRT86UME0RuiHyzScfFc4b4KZJaXtEPAwdaZCeS3E
	 AF+NZOY21RRG/4mICuTHFF02ICQS8G4+tLzbMqv8fU2bbLzPrKYerGN5tfMt6+j//8
	 qANbKdp+iNM2yJRC+xSbWiKMLnafVhvXRxgoBVMo=
From: "anlauf at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug fortran/86100] Spurious error with -fcheck=bounds and
 allocatable class(*) array components
Date: Wed, 08 May 2024 19:26:03 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: fortran
X-Bugzilla-Version: 8.1.1
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: anlauf at gcc dot gnu.org
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: cc
Message-ID: <bug-86100-4-vCsZ8cAlfi@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-86100-4@http.gcc.gnu.org/bugzilla/>
References: <bug-86100-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
List-Id: <gcc-bugs.sourceware.org>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D86100

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 =3D 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 =3D a      ! Array bound mismatch for dimension 1 of array '<<unknown=
>>'
(12/3)
    !b%m =3D a%m ! no runtime error with -fcheck=3Dbounds
  end subroutine foo
end

This fails as indicated.

Note that 12=3D3*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 =3D gfc_conv_descriptor_size (from_data, 1);
          from_len =3D fold_convert (TREE_TYPE (orig_nelems), from_len);
          tmp =3D fold_build2_loc (input_location, NE_EXPR,
                                  logical_type_node, from_len, orig_nelems);
          msg =3D 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?=