help with g++ and strict aliasing on x86-64

[Andrew Haley]

On 11/22/2010 06:14 PM, Ian Lance Taylor wrote:
> Alberto Griggio <alberto.griggio@gmail.com> writes:
> 
>> My OS is Debian GNU/Linux 5.0, compiler is
>> g++-4.1 (GCC) 4.1.3 20080704 (prerelease) (Debian 4.1.2-25)
>> platform x86-64
> 
>>               head_ = new (mem) Link;
> 
>> If I uncomment the "may_alias" attribute, everything works.
> 
> There have been a few bugs in the handling of placement new with regard
> to aliasing.  See in particular http://gcc.gnu.org/PR29286 .  As far as
> I know these bugs are fixed in current releases but they are apparently
> not fixed in the older release you are using.

Ah.  Albert, please ignore my posting.

It looked like astraightforward aliasing violation.

Andrew.