This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: Improve i386 add
- From: Michael Matz <matz at suse dot de>
- To: Richard Henderson <rth at redhat dot com>
- Cc: Jan Hubicka <jh at suse dot cz>, <gcc-patches at gcc dot gnu dot org>
- Date: Mon, 31 Mar 2003 10:43:14 +0200 (CEST)
- Subject: Re: Improve i386 add
Hi,
On Fri, 28 Mar 2003, Richard Henderson wrote:
> > I always tought reload first looks at the instruction and when the
> > instruction simply match it does not compute the costs at all.
> > It starts working hard only when the instruction happen to require
> > reloading?
>
> That's for simple moves only, with reg->reg cost of 2.
No, that's the first early-out. But later in the loop over all
alternatives, there is another early-out. Look for the "goto finish" in
the "if (losers == 0)" condition.
Ciao,
Michael.