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From: "bangerth at math dot tamu dot edu" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/30252] [4.2 regression] miscompilation of sigc++-2.0 based code with -fstrict-aliasing
Date: Tue, 01 May 2007 01:39:00 -0000 [thread overview]
Message-ID: <20070501013919.14097.qmail@sourceware.org> (raw)
In-Reply-To: <bug-30252-7958@http.gcc.gnu.org/bugzilla/>
------- Comment #14 from bangerth at math dot tamu dot edu 2007-05-01 02:39 -------
Subject: Re: [4.2 regression] miscompilation
of sigc++-2.0 based code with -fstrict-aliasing
> > typedef typed_slot_rep<T_functor> typed_slot;
> > typed_slot *typed_rep = static_cast<typed_slot*>(rep);
> > return (typed_rep->functor_)();
> >
> > This code could violate C++ aliasing rules.
>
> But:
> template <class T_functor>
> struct typed_slot_rep : public slot_rep
>
> so it looks like it might be valid.
But only, of course, if the pointer actually points to a typed_slot_rep.
Maybe someone who can reproduce the bug can make the following test:
- add a virtual destructor to slot_rep
- change the static_cast to a dynamic_cast
If the object pointed to is not a typed_slot_rep (in which the static_cast
in the original code would have been in error), then the code should
probably segfault or so...
W.
-------------------------------------------------------------------------
Wolfgang Bangerth email: bangerth@math.tamu.edu
www: http://www.math.tamu.edu/~bangerth/
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30252
next prev parent reply other threads:[~2007-05-01 1:39 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-18 15:56 [Bug tree-optimization/30252] New: [4.2/4.3 " belyshev at depni dot sinp dot msu dot ru
2006-12-18 15:57 ` [Bug tree-optimization/30252] " belyshev at depni dot sinp dot msu dot ru
2006-12-18 18:24 ` pinskia at gcc dot gnu dot org
2006-12-18 19:04 ` pinskia at gcc dot gnu dot org
2006-12-19 11:11 ` [Bug tree-optimization/30252] [4.2 " belyshev at depni dot sinp dot msu dot ru
2006-12-27 16:18 ` rguenth at gcc dot gnu dot org
2006-12-27 20:19 ` belyshev at depni dot sinp dot msu dot ru
2007-02-19 20:52 ` mmitchel at gcc dot gnu dot org
2007-04-29 7:02 ` pinskia at gcc dot gnu dot org
2007-04-29 8:58 ` belyshev at depni dot sinp dot msu dot ru
2007-04-30 2:25 ` bangerth at dealii dot org
2007-04-30 14:16 ` pluto at agmk dot net
2007-04-30 14:29 ` pluto at agmk dot net
2007-04-30 14:43 ` bangerth at dealii dot org
2007-05-01 1:11 ` giovannibajo at libero dot it
2007-05-01 1:39 ` bangerth at math dot tamu dot edu [this message]
2007-05-01 7:59 ` pluto at agmk dot net
2007-05-01 12:35 ` rguenth at gcc dot gnu dot org
2007-05-01 13:01 ` rguenth at gcc dot gnu dot org
2007-05-01 13:05 ` [Bug c++/30252] " rguenth at gcc dot gnu dot org
2007-05-02 20:59 ` mmitchel at gcc dot gnu dot org
2007-05-13 0:43 ` ismail at pardus dot org dot tr
2007-05-13 10:34 ` rguenth at gcc dot gnu dot org
2007-05-13 12:02 ` rguenth at gcc dot gnu dot org
2007-05-14 19:04 ` dberlin at gcc dot gnu dot org
2007-05-14 21:26 ` mmitchel at gcc dot gnu dot org
2007-05-15 7:59 ` rguenth at gcc dot gnu dot org
2007-06-04 15:28 ` rguenth at gcc dot gnu dot org
2007-06-04 15:45 ` rguenth at gcc dot gnu dot org
2007-06-05 9:27 ` rguenth at gcc dot gnu dot org
2007-06-05 12:05 ` rguenth at gcc dot gnu dot org
2007-06-05 15:01 ` rguenth at gcc dot gnu dot org
2007-06-05 15:57 ` rguenth at gcc dot gnu dot org
2007-06-05 16:20 ` dberlin at dberlin dot org
2007-06-05 16:30 ` rguenther at suse dot de
2007-06-05 17:45 ` dberlin at dberlin dot org
2007-06-05 18:25 ` matz at gcc dot gnu dot org
2007-06-05 19:07 ` dberlin at dberlin dot org
2007-06-05 19:59 ` rguenther at suse dot de
2007-06-05 22:44 ` dberlin at dberlin dot org
2007-06-06 8:50 ` rguenther at suse dot de
2007-06-06 15:52 ` dberlin at dberlin dot org
2007-06-19 9:24 ` rguenth at gcc dot gnu dot org
2007-06-19 9:46 ` rguenth at gcc dot gnu dot org
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