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Re: ccc vs. gcc today



On Tue, Dec 02, 2003 at 08:20:53AM -0600, John Goerzen wrote:
> On Tue, Dec 02, 2003 at 02:40:54AM -0800, Phil Carmody wrote:
> > --- John Goerzen <jgoerzen@complete.org> wrote:
> > > I'm interested in how ccc and gcc compare today wrt speed of generated
> > > code on Alpha.  Is gcc 3.3 as good as ccc?
> > 
> > For 21164s, building Dan Bernstein's DJBFFT library, ccc produces 
> > noticably faster code than gcc-3.3. At least 5% faster across the
> > board, up to 50% faster for some functions.
> 
> Does this hold even for things that are not directly math-related?

IIRC, it does NOT hold for normal/integer stuff, as GCC seems to hold
it's own in those areas.

> I'm using apt-build right now to build some key libraries with
> -mcpu=ev56 -O3 and hope that'll do the trick, but at the same time, I'm
> wondering if ccc would do better -- and how easy it is to use it in
> place of gcc.

Yes, rebuilding key libraries, as well as the kernel, for a specific
CPU/platform should help a good bit, if my results of a small GENTOO
install are any indication...

But, CCC is difficult, if not impossible, to use on some packages,
notably GLIBC and XFree86, as best I can remember.

Good luck.

 --Jay++

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Jay A Estabrook                            HPTC - LINUX support
Hewlett-Packard Company - MRO1-2/K15       (508) 467-2080
200 Forest Street, Marlboro MA 01752       Jay.Estabrook@hp.com
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