RFC: Enable multi-arch support for i386

[Joseph Myers]

On Mon, 17 Aug 2015, H.J. Lu wrote:

> Since _dl_x86_cpu_features is available for i386 now, we can
> move sysdeps/i386/i686/multiarch to sysdeps/i386/multiarch.
> That means to make multi-arch available for i486 and i586.
> Should I post a patch to do it?

I think the principle of having it available there makes sense.  However, 
various files in sysdeps/i386/i686/multiarch include other files from ../ 
(i.e. i686 versions) or ../i486/ or ../i586/.  So you'd need to make sure 
such a change doesn't pessimize things or use unavailable instructions in 
those fallback versions - the files should include the i686/ versions if 
__i686__ is defined, etc., making sure to include the best version 
applicable to the processor for which glibc is compiled (of course i486/ 
versions are always OK to use since i386 isn't supported any more).

-- 
Joseph S. Myers
joseph@codesourcery.com