[Bug fortran/54833] New: Don't wrap __builtin_free(a) in if (a != NULL)

[Bug fortran/54833] New: Don't wrap __builtin_free(a) in if (a != NULL)

[tkoenig at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54833

             Bug #: 54833
           Summary: Don't wrap __builtin_free(a) in if (a != NULL)
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: fortran
        AssignedTo: tkoenig@gcc.gnu.org
        ReportedBy: tkoenig@gcc.gnu.org


The Fortran front end at the moment generates many calls
to __builtin_free with

      if (a.data != 0B)
        {
          __builtin_free ((void *) a.data);
        }
      a.data = 0B;

This is not necessary, because free(NULL) is well-defined no-op.

[Bug fortran/54833] Don't wrap __builtin_free(a) in if (a != NULL)

[tkoenig at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54833

Thomas Koenig <tkoenig at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2012-10-06
     Ever Confirmed|0                           |1

[Bug fortran/54833] Don't wrap __builtin_free(a) in if (a != NULL)

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54833

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

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

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-10-07 15:51:51 UTC ---
It depends on what is the probability that the pointer is NULL.  If it is
unlikely, then unconditional free is the right choice, if NULL is very likely,
then the test may be less expensive (avoids call including likely PLT slot
overhead and comparison at least).

[Bug fortran/54833] Don't wrap __builtin_free(a) in if (a != NULL)

[fxcoudert at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54833

--- Comment #2 from Francois-Xavier Coudert <fxcoudert at gcc dot gnu.org> ---
Author: fxcoudert
Date: Mon Aug 31 10:54:36 2015
New Revision: 227336

URL: https://gcc.gnu.org/viewcvs?rev=227336&root=gcc&view=rev
Log:
        PR fortran/54833
        * trans.c (gfc_call_free): Don't check if pointer is NULL.
        * trans.h (gfc_call_free): Adjust comment.

Modified:
    trunk/gcc/fortran/ChangeLog
    trunk/gcc/fortran/trans.c
    trunk/gcc/fortran/trans.h

[Bug fortran/54833] Don't wrap __builtin_free(a) in if (a != NULL)

[fxcoudert at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54833

Francois-Xavier Coudert <fxcoudert at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
                 CC|                            |fxcoudert at gcc dot gnu.org
         Resolution|---                         |FIXED
           Assignee|tkoenig at gcc dot gnu.org         |fxcoudert at gcc dot gnu.org
   Target Milestone|---                         |6.0

--- Comment #3 from Francois-Xavier Coudert <fxcoudert at gcc dot gnu.org> ---
Fixed on trunk.