[Bug fortran/95837] New: derived-type components of character kind=4 – wrong code with component access (kind=4 ignored)

[Bug fortran/95837] New: derived-type components of character kind=4 – wrong code with component access (kind=4 ignored)

[burnus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95837

            Bug ID: 95837
           Summary: derived-type components of character kind=4 – wrong
                    code with component access (kind=4 ignored)
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: burnus at gcc dot gnu.org
  Target Milestone: ---

Compare:
---------------
type t
  character(len=:, kind=4), pointer :: str2
end type t
type(t) :: var
character(len=:, kind=4), pointer :: str

str(1:1) = 4_"a"
str(1:2) = 4_"bc"
var%str2(1:1) = 4_"d"
var%str2(1:2) = 4_"ef"
end
---------------

The dump shows that 'str' is properly handled:
  (*str)[1]{lb: 1 sz: 4} = "a\x00\x00"[1]{lb: 1 sz: 4};
  __builtin_memmove ((void *) str,
                     (void *) &"b\x00\x00\x00c\x00\x00"[1]{lb: 1 sz: 4}, 8);

But the component reference ignores the kind=4:
   *(character(kind=1) *) var.str2 = 100;
  __builtin_memmove ((void *) var.str2,
                     (void *) &"ef"[1]{lb: 1 sz: 1}, 2);

[Bug fortran/95837] derived-type components of character kind=4 – wrong code with component access (kind=4 ignored)

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95837

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2020-06-23
             Status|UNCONFIRMED                 |WAITING

--- Comment #1 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
The problem seems more serious.

type t
  character(len=:, kind=4), pointer :: str2
end type t
type(t) :: var
character(len=:, kind=4), pointer :: str

print *, kind(str), kind(var%str2)
str(1:1) = 4_"a"
end

result

% ./a.out 
           4           4

Program received signal SIGSEGV: Segmentation fault - invalid memory reference.

[Bug fortran/95837] derived-type components of character kind=4 – wrong code with component access (kind=4 ignored)

[kargl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95837

kargl at gcc dot gnu.org changed:

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

--- Comment #2 from kargl at gcc dot gnu.org ---
(In reply to Dominique d'Humieres from comment #1)
> The problem seems more serious.
> 
> type t
>   character(len=:, kind=4), pointer :: str2
> end type t
> type(t) :: var
> character(len=:, kind=4), pointer :: str
> 
> print *, kind(str), kind(var%str2)
> str(1:1) = 4_"a"
> end
> 
> result
> 
> % ./a.out 
>            4           4

Yes, there is a serious problem with the Fortran code!

str is an undefined pointer.  The line 'str(1:1) = 4_"a"'
is invalid.

[Bug fortran/95837] derived-type components of character kind=4 – wrong code with component access (kind=4 ignored)

[kargl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95837

--- Comment #3 from kargl at gcc dot gnu.org ---
(In reply to kargl from comment #2)
> (In reply to Dominique d'Humieres from comment #1)
> > The problem seems more serious.
> > 
> > type t
> >   character(len=:, kind=4), pointer :: str2
> > end type t
> > type(t) :: var
> > character(len=:, kind=4), pointer :: str
> > 
> > print *, kind(str), kind(var%str2)
> > str(1:1) = 4_"a"
> > end
> > 
> > result
> > 
> > % ./a.out 
> >            4           4
> 
> Yes, there is a serious problem with the Fortran code!
> 
> str is an undefined pointer.  The line 'str(1:1) = 4_"a"'
> is invalid.

In fact, after a quick scan of the Fortran 2018 standard.
The PR is likely invalid.  Allocation on assignment applies
to ALLOCATABLE variables not undefined or disassociated
pointers.

Yep.  Definitely invalid.

Fortran 2018,
10.2.1.2 Intrinsic assignment statement
p. 160

If the variable is a pointer, it shall be associated with a definable
target such that the type, type parameters, and shape of the target and
expr conform.

[Bug fortran/95837] derived-type components of character kind=4 – wrong code with component access (kind=4 ignored)

[kargl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95837

kargl at gcc dot gnu.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P4
           Keywords|wrong-code                  |

--- Comment #4 from kargl at gcc dot gnu.org ---
Remove "wrong-code" keyword.

[Bug fortran/95837] derived-type components of character kind=4 – wrong code with component access (kind=4 ignored)

[burnus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95837

Tobias Burnus <burnus at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |NEW
           Keywords|                            |rejects-valid, wrong-code

--- Comment #5 from Tobias Burnus <burnus at gcc dot gnu.org> ---
Patch: https://gcc.gnu.org/pipermail/gcc-patches/2020-June/548779.html

[Bug fortran/95837] derived-type components of character kind=4 – wrong code with component access (kind=4 ignored)

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95837

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Tobias Burnus <burnus@gcc.gnu.org>:

https://gcc.gnu.org/g:f48bffe70cba310461ec19ffcd07c573a6b86575

commit r11-1654-gf48bffe70cba310461ec19ffcd07c573a6b86575
Author: Tobias Burnus <tobias@codesourcery.com>
Date:   Thu Jun 25 16:57:08 2020 +0200

    Fortran: Fix character-kind=4 substring resolution (PR95837)

    Testing showed that it is always set and its value matches
    always ts->kind (if available) or otherwise, if it is a variable,
    the sym->ts.kind.

    gcc/fortran/ChangeLog:

            PR fortran/95837
            * resolve.c (gfc_resolve_substring_charlen): Remove
            bogus ts.kind setting for the expression.

    gcc/testsuite/ChangeLog:

            PR fortran/95837
            * gfortran.dg/char4-subscript.f90: New test.

[Bug fortran/95837] derived-type components of character kind=4 – wrong code with component access (kind=4 ignored)

[burnus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95837

Tobias Burnus <burnus at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #7 from Tobias Burnus <burnus at gcc dot gnu.org> ---
FIXED on mainline = GCC 11.

[Bug fortran/95837] derived-type components of character kind=4 – wrong code with component access (kind=4 ignored)

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95837

--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Tobias Burnus <burnus@gcc.gnu.org>:

https://gcc.gnu.org/g:e0685fadb6aa7c9cc895bc14cbbe2b9026fa3a94

commit r11-2105-ge0685fadb6aa7c9cc895bc14cbbe2b9026fa3a94
Author: Tobias Burnus <tobias@codesourcery.com>
Date:   Wed Jul 15 12:29:44 2020 +0200

    libgomp.fortran/struct-elem-map-1.f90: Add char kind=4 tests

    As the Fortran PR 95837 has been fixed, the test could be be added.

    libgomp/ChangeLog:

            * testsuite/libgomp.fortran/struct-elem-map-1.f90: Remove unused
            variables; add character(kind=4) tests; update TODO comment.