[Bug libstdc++/63860] New: Ill-formed std::pair::swap implementation?

[Bug libstdc++/63860] New: Ill-formed std::pair::swap implementation?

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63860

            Bug ID: 63860
           Summary: Ill-formed std::pair::swap implementation?
           Product: gcc
           Version: 4.8.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hjl.tools at gmail dot com

According to

http://llvm.org/bugs/show_bug.cgi?id=21565

and

http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20141110/118441.html

std::pair::swap implementation in libstdc++ in GCC 4.8.3 is ill-formed.
I checked trunk and it isn't changed.  Is libstdc++ wrong here?

[Bug libstdc++/63860] Ill-formed std::pair::swap implementation?

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63860

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Most likely because 4.8.3 did not fully implement C++11.

[Bug libstdc++/63860] Ill-formed std::pair::swap implementation?

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63860

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2014-11-14
     Ever confirmed|0                           |1

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #1)
> Most likely because 4.8.3 did not fully implement C++11.

No, it's just a bug in libstdc++

[Bug libstdc++/63860] Ill-formed std::pair::swap implementation?

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63860

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Created attachment 33965
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33965&action=edit
untested patch

I think this makes the code valid

[Bug libstdc++/63860] Ill-formed std::pair::swap implementation?

[richard-gccbugzilla at metafoo dot co.uk]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63860

Richard Smith <richard-gccbugzilla at metafoo dot co.uk> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |richard-gccbugzilla@metafoo
                   |                            |.co.uk

--- Comment #4 from Richard Smith <richard-gccbugzilla at metafoo dot co.uk> ---
The proposed change looks correct to me. You'd need to also address the same
issue in std::array, std::priority_queue, std::stack, and std::queue (and in
the std::array variant in the debug and profile variants of libstdc++ too).

[Bug libstdc++/63860] Ill-formed std::pair::swap implementation?

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63860

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |redi at gcc dot gnu.org
            Version|4.8.3                       |5.0
   Target Milestone|---                         |5.0
      Known to fail|                            |4.8.4, 4.9.3, 5.0

--- Comment #5 from H.J. Lu <hjl.tools at gmail dot com> ---
Doesn't GCC 5 have the same problem?

[Bug libstdc++/63860] Ill-formed std::pair::swap implementation?

[ville.voutilainen at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63860

Ville Voutilainen <ville.voutilainen at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ville.voutilainen at gmail dot com

--- Comment #6 from Ville Voutilainen <ville.voutilainen at gmail dot com> ---
This is
http://cplusplus.github.io/LWG/lwg-active.html#2456
and I have a patch for it at
https://github.com/villevoutilainen/gcc/tree/is_nothrow_swappable
which will be submitted after gcc5 is released.

[Bug libstdc++/63860] Ill-formed std::pair::swap implementation?

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63860

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|5.0                         |5.2

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 5.1 has been released.