[Bug c/29938] [3.4.4/3.4.6/4.1.1] ARM structure pointer alignment problem with optimization

["bernard dot fouche at kuantic dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #2 from bernard dot fouche at kuantic dot com  2006-11-22 11:32 -------
Subject: Re:  [3.4.4/3.4.6/4.1.1] ARM structure pointer alignment
 problem with optimization

rearnsha at gcc dot gnu dot org wrote:
> ------- Comment #1 from rearnsha at gcc dot gnu dot org  2006-11-22 10:50 -------
> The compiler expects 'y' to be correctly aligned because the ABI says that it
> can expect this to be so.  If you write a program that then provides an
> unaligned value, then the behaviour is undefined and you can get any result the
> compiler feels like giving you.
>
> Hint: don't increment void* pointers (it's a gcc extension that permits this
> anyway) and then try to assign them to a structure.  Malloc provides memory
> that is correctly aligned for direct assignment to any structure type.
>
>
>   
Sorry for having taken your time for nothing. I'll read the ABI spec 
better next time. Too bad my target does not have alignment traps, I've 
fallen in the problem while building a packet with an odd size header.

Regards,

 Bernard


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29938