[Bug fortran/67977] New: allocatable strings, array section reallocated - non-standard behaviour

[Bug fortran/67977] New: allocatable strings, array section reallocated - non-standard behaviour

[mexas at bristol dot ac.uk]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67977

            Bug ID: 67977
           Summary: allocatable strings, array section reallocated -
                    non-standard behaviour
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mexas at bristol dot ac.uk
  Target Milestone: ---

character(:), allocatable :: z
z = "cockatoo"
write (*,*) z, len(z)
z(:) = ''
write (*,*) z, len(z)
end

with gfortran 4.9 to 6.0 this returns:

 cockatoo           8
            0

which is wrong. It should return:

 cockatoo           8
                    8

i.e. the length of variable "z" must not change
from the second assignment statement. This is because
the array section is used ( z(:) ), which should not
trigger reallocation. So "z" after the second assignment
must still be 8 characters long, all blanks.

Anton

[Bug fortran/67977] allocatable strings, array section reallocated - non-standard behaviour

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67977

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |wrong-code
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-10-16
                 CC|                            |pault at gcc dot gnu.org
     Ever confirmed|0                           |1
      Known to fail|                            |4.8.5, 4.9.3, 5.2.0, 6.0

--- Comment #1 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
Confirmed from 4.8 up to trunk (6.0).

[Bug fortran/67977] allocatable strings, array section reallocated - non-standard behaviour

[pault at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67977

--- Comment #2 from Paul Thomas <pault at gcc dot gnu.org> ---
Author: pault
Date: Sun Oct 18 09:31:21 2015
New Revision: 228940

URL: https://gcc.gnu.org/viewcvs?rev=228940&root=gcc&view=rev
Log:
2015-10-18  Paul Thomas  <pault@gcc.gnu.org>

        PR fortran/67177
        PR fortran/67977
        * primary.c (match_substring): Add an argument 'deferred' to
        flag that a substring reference with null start and end should
        not be optimized away for deferred length strings.
        (match_string_constant, gfc_match_rvalue): Set the argument.
        * trans-expr.c (alloc_scalar_allocatable_for_assignment): If
        there is a substring reference return.
        * trans-intrinsic.c (conv_intrinsic_move_alloc): For deferred
        characters, assign the 'from' string length to the 'to' string
        length. If the 'from' expression is deferred, set its string
        length to zero. If the 'to' expression has allocatable
        components, deallocate them.

2015-10-18  Paul Thomas  <pault@gcc.gnu.org>

        PR fortran/67177
        * gfortran.dg/move_alloc_15.f90: New test
        * gfortran.dg/move_alloc_16.f90: New test

        PR fortran/67977
        * gfortran.dg/deferred_character_assignment_1.f90: New test

Added:
    trunk/gcc/testsuite/gfortran.dg/deferred_character_assignment_1.f90
    trunk/gcc/testsuite/gfortran.dg/move_alloc_15.f90
    trunk/gcc/testsuite/gfortran.dg/move_alloc_16.f90
Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/primary.c
    trunk/gcc/fortran/trans-expr.c
    trunk/gcc/fortran/trans-intrinsic.c
    trunk/gcc/testsuite/ChangeLog

[Bug fortran/67977] allocatable strings, array section reallocated - non-standard behaviour

[pault at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67977

Paul Thomas <pault at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |pault at gcc dot gnu.org

--- Comment #3 from Paul Thomas <pault at gcc dot gnu.org> ---
Since I have fixed it on trunk, I might as well assign it to myself!

It will be fixed on 5 branch next weekend.

Cheers

Paul

[Bug fortran/67977] allocatable strings, array section reallocated - non-standard behaviour

[davidgkinniburgh at yahoo dot co.uk]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67977

David Kinniburgh <davidgkinniburgh at yahoo dot co.uk> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |davidgkinniburgh at yahoo dot co.u
                   |                            |k

--- Comment #4 from David Kinniburgh <davidgkinniburgh at yahoo dot co.uk> ---
Does this fix 63469?

[Bug fortran/67977] allocatable strings, array section reallocated - non-standard behaviour

[paul.richard.thomas at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67977

--- Comment #5 from paul.richard.thomas at gmail dot com <paul.richard.thomas at gmail dot com> ---
Hi David,

Yes it does. Thank you for bring this PR to my attention. I'll mark it
appropriately.

Cheers

Paul

On 19 October 2015 at 13:42, davidgkinniburgh at yahoo dot co.uk
<gcc-bugzilla@gcc.gnu.org> wrote:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67977
>
> David Kinniburgh <davidgkinniburgh at yahoo dot co.uk> changed:
>
>            What    |Removed                     |Added
> ----------------------------------------------------------------------------
>                  CC|                            |davidgkinniburgh at yahoo dot co.u
>                    |                            |k
>
> --- Comment #4 from David Kinniburgh <davidgkinniburgh at yahoo dot co.uk> ---
> Does this fix 63469?
>
> --
> You are receiving this mail because:
> You are on the CC list for the bug.
> You are the assignee for the bug.

[Bug fortran/67977] allocatable strings, array section reallocated - non-standard behaviour

[pault at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67977

--- Comment #6 from Paul Thomas <pault at gcc dot gnu.org> ---
Author: pault
Date: Mon Oct 26 17:25:03 2015
New Revision: 229386

URL: https://gcc.gnu.org/viewcvs?rev=229386&root=gcc&view=rev
Log:
2015-10-26  Paul Thomas  <pault@gcc.gnu.org>

        PR fortran/67177
        PR fortran/67977
        * primary.c (match_substring): Add an argument 'deferred' to
        flag that a substring reference with null start and end should
        not be optimized away for deferred length strings.
        (match_string_constant, gfc_match_rvalue): Set the argument.
        * trans-expr.c (alloc_scalar_allocatable_for_assignment): If
        there is a substring reference return.
        * trans-intrinsic.c (conv_intrinsic_move_alloc): For deferred
        characters, assign the 'from' string length to the 'to' string
        length. If the 'from' expression is deferred, set its string
        length to zero. If the 'to' expression has allocatable
        components, deallocate them.

2015-10-26  Paul Thomas  <pault@gcc.gnu.org>

        PR fortran/67177
        * gfortran.dg/move_alloc_15.f90: New test
        * gfortran.dg/move_alloc_16.f90: New test

        PR fortran/67977
        * gfortran.dg/deferred_character_assignment_1.f90: New test

Added:
   
branches/gcc-5-branch/gcc/testsuite/gfortran.dg/deferred_character_assignment_1.f90
    branches/gcc-5-branch/gcc/testsuite/gfortran.dg/move_alloc_15.f90
    branches/gcc-5-branch/gcc/testsuite/gfortran.dg/move_alloc_16.f90
Modified:
    branches/gcc-5-branch/gcc/fortran/ChangeLog
    branches/gcc-5-branch/gcc/fortran/primary.c
    branches/gcc-5-branch/gcc/fortran/trans-expr.c
    branches/gcc-5-branch/gcc/fortran/trans-intrinsic.c
    branches/gcc-5-branch/gcc/testsuite/ChangeLog

[Bug fortran/67977] allocatable strings, array section reallocated - non-standard behaviour

[pault at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67977

Paul Thomas <pault at gcc dot gnu.org> changed:

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

--- Comment #7 from Paul Thomas <pault at gcc dot gnu.org> ---
Fixed on trunk and 5 branch.

Many thanks for the report

Paul