[Bug c++/32260] New: too many warning: dereferencing type-punned pointer will break strict-aliasing rules

[Bug c++/32260] New: too many warning: dereferencing type-punned pointer will break strict-aliasing rules

[sylvain dot pion at sophia dot inria dot fr]

The following code, compiled with -O2 -Wall (g++ 4.3 as of 20070607),
produces the following unexpected/annoying warning:

test_typeinfo.cpp: In function 'int main()':
test_typeinfo.cpp:5: warning: dereferencing type-punned pointer will break
strict-aliasing rules
test_typeinfo.cpp:5: warning: unused variable 't'


~> cat test_typeinfo.cpp 
#include <typeinfo>

int main()
{
  const std::type_info & t = typeid(int);
}


Is this really meant to warn for such a code???


-- 
           Summary: too many warning: dereferencing type-punned pointer will
                    break strict-aliasing rules
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: sylvain dot pion at sophia dot inria dot fr
  GCC host triplet: x86_64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32260

[Bug c++/32260] [4.3 Regression] too many warning: dereferencing type-punned pointer will break strict-aliasing rules

[pinskia at gcc dot gnu dot org]

------- Comment #1 from pinskia at gcc dot gnu dot org  2007-06-11 21:19 -------
Confirmed, I have not looked into this close enough but this is a front-end bug
as the type (and aliasing set) of the typeid variable is different from
std::type_info's.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
           Keywords|                            |alias, diagnostic
   Last reconfirmed|0000-00-00 00:00:00         |2007-06-11 21:19:44
               date|                            |
            Summary|too many warning:           |[4.3 Regression] too many
                   |dereferencing type-punned   |warning: dereferencing type-
                   |pointer will break strict-  |punned pointer will break
                   |aliasing rules              |strict-aliasing rules
   Target Milestone|---                         |4.3.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32260

[Bug c++/32260] [4.3 Regression] too many warning: dereferencing type-punned pointer will break strict-aliasing rules

[mmitchel at gcc dot gnu dot org]

-- 

mmitchel at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32260

[Bug c++/32260] [4.3 Regression] too many warning: dereferencing type-punned pointer will break strict-aliasing rules

[pcarlini at suse dot de]

------- Comment #2 from pcarlini at suse dot de  2007-09-28 17:04 -------
Short term at least, could be considered a duplicate of PR32256 (and PR32368).


-- 

pcarlini at suse dot de changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pcarlini at suse dot de


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32260

[Bug c++/32260] [4.3 Regression] too many warning: dereferencing type-punned pointer will break strict-aliasing rules

[pcarlini at suse dot de]

------- Comment #3 from pcarlini at suse dot de  2007-10-26 09:00 -------
*** Bug 33902 has been marked as a duplicate of this bug. ***


-- 

pcarlini at suse dot de changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |benoit dot hudson at gmail
                   |                            |dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32260

[Bug c++/32260] [4.3 Regression] too many warning: dereferencing type-punned pointer will break strict-aliasing rules

[jakub at gcc dot gnu dot org]

------- Comment #4 from jakub at gcc dot gnu dot org  2007-11-01 11:57 -------
Testing a fix.


-- 

jakub at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |jakub at gcc dot gnu dot org
                   |dot org                     |
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2007-06-11 21:19:44         |2007-11-01 11:57:35
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32260

[Bug c++/32260] [4.3 Regression] too many warning: dereferencing type-punned pointer will break strict-aliasing rules

[jakub at gcc dot gnu dot org]

------- Comment #5 from jakub at gcc dot gnu dot org  2007-11-01 22:50 -------
Subject: Bug 32260

Author: jakub
Date: Thu Nov  1 22:50:32 2007
New Revision: 129835

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=129835
Log:
        PR c++/32260
        * rtti.c (enum_tinfo_kind): Fix TK_TYPE_INFO_TYPE comment.
        (typeid_ok_p): Use the same alias set for abi::__type_info_pseudo
        as for std::type_info.

        * g++.dg/rtti/typeid7.C: New test.

Added:
    trunk/gcc/testsuite/g++.dg/rtti/typeid7.C
Modified:
    trunk/gcc/cp/ChangeLog
    trunk/gcc/cp/rtti.c
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32260

[Bug c++/32260] [4.3 Regression] too many warning: dereferencing type-punned pointer will break strict-aliasing rules

[jakub at gcc dot gnu dot org]

------- Comment #6 from jakub at gcc dot gnu dot org  2007-11-01 23:09 -------
Fixed.


-- 

jakub at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32260

[Bug c++/32260] [4.3 Regression] too many warning: dereferencing type-punned pointer will break strict-aliasing rules

[pcarlini at suse dot de]

------- Comment #7 from pcarlini at suse dot de  2007-11-11 14:04 -------
*** Bug 34066 has been marked as a duplicate of this bug. ***


-- 

pcarlini at suse dot de changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |guillaume dot melquiond at
                   |                            |ens-lyon dot fr


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32260