Re: [patch] Cleaning up amd64 kernel optimization options

On Fri Dec 23 11, Dimitry Andric wrote:
> On 2011-12-23 18:55, Kostik Belousov wrote:
> >On Fri, Dec 23, 2011 at 06:03:42PM +0100, Dimitry Andric wrote:
> ...
> >>The only thing my patch makes sure of, is that amd64 does the same thing
> >>as all other arches, e.g.: compile with a low optimization settings for
> >>debug (-O, which is equivalent to -O1), compile with arch-specific high
> >>optimization settings for release (-O2 plus whatever is required for the
> >>arch, or lower if optimization breaks things).
> >
> >Release is built with -g for long time, this is where the symbol files
> >in /boot/kernel comes from.
> 
> Ah, that is done via 'makeoptions DEBUG=-g' in the kernel configuration
> file, right?  I didn't realize that was kept in for a release.  But even
> in that case, amd64 is somehow different from the other arches, which
> all get compiled with -O instead.
> 
> If people prefer that to stay as it is, I'll change the diff so only
> -frename-registers gets removed when clang is used, as clang does not
> support this flag.

i think you should go ahead with the changes:

1) get amd64 in line with the other archs when debugging was requested (turning
   the default optimisation from -O2 to -O)
2) only specify -frename-registers on amd64, when gcc is the requested compiler

i'd say: commit it. :)

...sorry we got carried away, but optimisation flags tend to trigger a lot of
discussion. ;)

cheers.
alex