This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: CC0 to CCmode conversion
- From: Denis Chertykov <denisc at overta dot ru>
- To: Bernardo Innocenti <bernie at develer dot com>
- Cc: Denis Chertykov <denisc at overta dot ru>, gcc at gcc dot gnu dot org
- Date: 19 Mar 2005 16:38:37 +0300
- Subject: Re: CC0 to CCmode conversion
- References: <auto-000020618887@overta.ru> <423B6880.20503@develer.com>
Bernardo Innocenti <bernie@develer.com> writes:
> Denis Chertykov wrote:
>
> > I have converted the AVR port from CC0 to CCmode.
>
> That's indeed very good news. Incidentally, CC0
> conversion of the AVR target was being discussed
> in an off-list thread with Andy Hutchinson.
>
>
> > But may be I have converted the port in wrong way.
> > (It's because I was interested in *this* way.)
>
> Uh? That's very bad news.
>
>
> > I have used CCmode register and havn't added the
> > '(clobber (reg:QI CC_REGNUM))' to any insn that really clobber the
> > CC_REGNUM just because AVR is'n needed in scheduling.
> > I think that sequence of compare + cond-jump will exists in any
> > compiler pass.
> > The port was successfully tested without new regressions.
>
> Did you notice any pessimization spots in the generated
> code? IIRC, the converted H8 backend required some
> massaging before it was back on par with the old
> version.
I have a bit pessimization but compare/branch operations can be
optimized even more than CC0 version.
Denis.