public inbox for gcc-bugs@sourceware.org
help / color / mirror / Atom feed
* [Bug libstdc++/56085] New: Unsafe negation in C++03 pow(complex,int)
@ 2013-01-23 16:01 glisse at gcc dot gnu.org
  2013-01-23 16:46 ` [Bug libstdc++/56085] " rguenth at gcc dot gnu.org
                   ` (4 more replies)
  0 siblings, 5 replies; 6+ messages in thread
From: glisse at gcc dot gnu.org @ 2013-01-23 16:01 UTC (permalink / raw)
  To: gcc-bugs


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56085

             Bug #: 56085
           Summary: Unsafe negation in C++03 pow(complex,int)
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: glisse@gcc.gnu.org


template<typename _Tp>
    inline complex<_Tp>
    pow(const complex<_Tp>& __z, int __n)
    {
      return __n < 0
        ? complex<_Tp>(1) / std::__complex_pow_unsigned(__z, -__n)
        : std::__complex_pow_unsigned(__z, __n);

If I understand correctly, -__n is undefined behavior for INT_MIN, and this
should use -(unsigned)__n instead to be safe. This is not just theoretical,
other projects had to do similar changes because gcc starting with 4.7 would
produce wrong code otherwise.


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [Bug libstdc++/56085] Unsafe negation in C++03 pow(complex,int)
  2013-01-23 16:01 [Bug libstdc++/56085] New: Unsafe negation in C++03 pow(complex,int) glisse at gcc dot gnu.org
@ 2013-01-23 16:46 ` rguenth at gcc dot gnu.org
  2013-01-24 11:20 ` paolo.carlini at oracle dot com
                   ` (3 subsequent siblings)
  4 siblings, 0 replies; 6+ messages in thread
From: rguenth at gcc dot gnu.org @ 2013-01-23 16:46 UTC (permalink / raw)
  To: gcc-bugs


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56085

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |wrong-code
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2013-01-23
     Ever Confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> 2013-01-23 16:46:02 UTC ---
Confirmed.  Or use __builtin_absu() - bah you'd need to add it first ;)


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [Bug libstdc++/56085] Unsafe negation in C++03 pow(complex,int)
  2013-01-23 16:01 [Bug libstdc++/56085] New: Unsafe negation in C++03 pow(complex,int) glisse at gcc dot gnu.org
  2013-01-23 16:46 ` [Bug libstdc++/56085] " rguenth at gcc dot gnu.org
@ 2013-01-24 11:20 ` paolo.carlini at oracle dot com
  2013-01-24 12:21 ` paolo at gcc dot gnu.org
                   ` (2 subsequent siblings)
  4 siblings, 0 replies; 6+ messages in thread
From: paolo.carlini at oracle dot com @ 2013-01-24 11:20 UTC (permalink / raw)
  To: gcc-bugs


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56085

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
         AssignedTo|unassigned at gcc dot       |paolo.carlini at oracle dot
                   |gnu.org                     |com

--- Comment #2 from Paolo Carlini <paolo.carlini at oracle dot com> 2013-01-24 11:20:21 UTC ---
Thanks Marc for noticing, the core problem seems very old, but probably when it
belonged to __pow_helper was less visible because of (non-)inlining. Let's fix
this.


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [Bug libstdc++/56085] Unsafe negation in C++03 pow(complex,int)
  2013-01-23 16:01 [Bug libstdc++/56085] New: Unsafe negation in C++03 pow(complex,int) glisse at gcc dot gnu.org
  2013-01-23 16:46 ` [Bug libstdc++/56085] " rguenth at gcc dot gnu.org
  2013-01-24 11:20 ` paolo.carlini at oracle dot com
@ 2013-01-24 12:21 ` paolo at gcc dot gnu.org
  2013-01-24 12:22 ` paolo.carlini at oracle dot com
  2013-01-24 12:22 ` paolo at gcc dot gnu.org
  4 siblings, 0 replies; 6+ messages in thread
From: paolo at gcc dot gnu.org @ 2013-01-24 12:21 UTC (permalink / raw)
  To: gcc-bugs


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56085

--- Comment #3 from paolo at gcc dot gnu.org <paolo at gcc dot gnu.org> 2013-01-24 12:21:06 UTC ---
Author: paolo
Date: Thu Jan 24 12:20:57 2013
New Revision: 195421

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=195421
Log:
2013-01-24  Paolo Carlini  <paolo.carlini@oracle.com>

    PR libstdc++/56085
    * include/std/complex (pow(const complex<>&, int)): Avoid __n
    signed overflow.

Modified:
    trunk/libstdc++-v3/ChangeLog
    trunk/libstdc++-v3/include/std/complex


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [Bug libstdc++/56085] Unsafe negation in C++03 pow(complex,int)
  2013-01-23 16:01 [Bug libstdc++/56085] New: Unsafe negation in C++03 pow(complex,int) glisse at gcc dot gnu.org
                   ` (2 preceding siblings ...)
  2013-01-24 12:21 ` paolo at gcc dot gnu.org
@ 2013-01-24 12:22 ` paolo.carlini at oracle dot com
  2013-01-24 12:22 ` paolo at gcc dot gnu.org
  4 siblings, 0 replies; 6+ messages in thread
From: paolo.carlini at oracle dot com @ 2013-01-24 12:22 UTC (permalink / raw)
  To: gcc-bugs


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56085

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.7.3

--- Comment #5 from Paolo Carlini <paolo.carlini at oracle dot com> 2013-01-24 12:22:31 UTC ---
Fixed mainline and 4.7.3.


^ permalink raw reply	[flat|nested] 6+ messages in thread

* [Bug libstdc++/56085] Unsafe negation in C++03 pow(complex,int)
  2013-01-23 16:01 [Bug libstdc++/56085] New: Unsafe negation in C++03 pow(complex,int) glisse at gcc dot gnu.org
                   ` (3 preceding siblings ...)
  2013-01-24 12:22 ` paolo.carlini at oracle dot com
@ 2013-01-24 12:22 ` paolo at gcc dot gnu.org
  4 siblings, 0 replies; 6+ messages in thread
From: paolo at gcc dot gnu.org @ 2013-01-24 12:22 UTC (permalink / raw)
  To: gcc-bugs


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56085

--- Comment #4 from paolo at gcc dot gnu.org <paolo at gcc dot gnu.org> 2013-01-24 12:21:33 UTC ---
Author: paolo
Date: Thu Jan 24 12:21:24 2013
New Revision: 195422

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=195422
Log:
2013-01-24  Paolo Carlini  <paolo.carlini@oracle.com>

    PR libstdc++/56085
    * include/std/complex (pow(const complex<>&, int)): Avoid __n
    signed overflow.

Modified:
    branches/gcc-4_7-branch/libstdc++-v3/ChangeLog
    branches/gcc-4_7-branch/libstdc++-v3/include/std/complex


^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2013-01-24 12:22 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2013-01-23 16:01 [Bug libstdc++/56085] New: Unsafe negation in C++03 pow(complex,int) glisse at gcc dot gnu.org
2013-01-23 16:46 ` [Bug libstdc++/56085] " rguenth at gcc dot gnu.org
2013-01-24 11:20 ` paolo.carlini at oracle dot com
2013-01-24 12:21 ` paolo at gcc dot gnu.org
2013-01-24 12:22 ` paolo.carlini at oracle dot com
2013-01-24 12:22 ` paolo at gcc dot gnu.org

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).