Re: (un)aligned accesses on x86 platform.

[Andrew Pinski <pinskia at gmail dot com>]

You define STRICT_ALIGNED to be 1 in i386.h or provide an option to  
turn that on/off like the rs6000 target does.

Thanks,
Andrew Pinski

Sent from my iPhone

On Mar 8, 2010, at 7:37 AM, PaweÅ Sikora <pluto@agmk.net> wrote:

> hi,
>
> during development a cross platform appliacation on x86 workstation
> i've enabled an alignemnt checking [1] to catch possible erroneous
> code before it appears on client's sparc/arm cpu with sigbus ;)
>
> it works pretty fine and catches alignment violations but Jakub  
> Jelinek
> had told me (on glibc bugzilla) that gcc on x86 can still dereference
> an unaligned pointer (except for vector insns).
> i suppose it means that gcc can emit e.g. movl for access a short int
> (or maybe others scenarios) in some cases and violates cpu alignment  
> rules.
>
> so, is it possible to instruct gcc-x86 to always use suitable loads/ 
> stores
> like on sparc/arm?
>
> [1] "AC" bit - http://en.wikipedia.org/wiki/FLAGS_register_(computing)
>
> BR,
> Pawel.