[Bug fortran/57791] New: Waste work in gfc_check_pointer_assign()

[Bug fortran/57791] New: Waste work in gfc_check_pointer_assign()

[pchang9 at cs dot wisc.edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57791

            Bug ID: 57791
           Summary: Waste work in gfc_check_pointer_assign()
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pchang9 at cs dot wisc.edu
                CC: nistor1 at illinois dot edu

Created attachment 30430
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30430&action=edit
Suggested patch

The problem appears in revision 200588 in version 4.9. I have attached a
one-line patch that fixes it.

In method "gfc_check_pointer_assign()" in expr.c, the loop on line 3763 should
break immediately after "warn" is set to "true". All the iterations after
"warn" set to "true" do not perform any useful work, at best they just set
"warn" again to "true".

[Bug fortran/57791] Waste work in gfc_check_pointer_assign()

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57791

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

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

--- Comment #1 from Tobias Burnus <burnus at gcc dot gnu.org> ---
(In reply to Po-Chun Chang from comment #0)
> Suggested patch
> 
> In method "gfc_check_pointer_assign()" in expr.c, the loop on line 3763
> should break immediately after "warn" is set to "true". All the iterations
> after "warn" set to "true" do not perform any useful work, at best they just
> set "warn" again to "true".

I concur.

(Note that the nesting depth is rather shallow [one or two, rarely three and
essentially never four or more] and only pointer comparisons are done, which is
computationally cheap. Thus, the current version doesn't waste many cycles.)

[Bug fortran/57791] Wasted work in gfc_check_pointer_assign()

[pchang9 at cs dot wisc.edu]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57791

--- Comment #2 from Po-Chun Chang <pchang9 at cs dot wisc.edu> ---
Patch sent to gcc-patches@ and fortran@

http://gcc.gnu.org/ml/gcc-patches/2013-07/msg01056.html
http://gcc.gnu.org/ml/fortran/2013-07/msg00070.html

[Bug fortran/57791] Wasted work in gfc_check_pointer_assign()

[law at redhat dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57791

Jeffrey A. Law <law at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
                 CC|                            |law at redhat dot com
         Resolution|---                         |FIXED

--- Comment #3 from Jeffrey A. Law <law at redhat dot com> ---
Patch installed on trunk.