Re: Patch: MOVE_RATIO on x86 prescott

[Dale Johannesen <dalej at apple dot com>]

On Aug 27, 2005, at 1:11 AM, Richard Guenther wrote:
> On 8/27/05, Dale Johannesen <dalej@apple.com> wrote:
> > Feedback from users led us to conclude this is set too low.
> > The test here tries copying arrays of size 9 to 16 words with
> > mainline (which uses 'rep movsl') and a modified copy with
> > the patch below (which uses loads and stores); you'll see
> > loads and stores are faster in all cases, by 2 to 1 or more.

> > This patch increases MOVE_RATIO to 17 for Prescott, with
> > the effect that the 'rep; movsl' sequence is never used.
> > A SPEC run shows +1/2% on int (which is within the margin
> > of error, really), break-even on FP.  OK?
>
> I don't think this is appropriate for stage3

Fair enough.  It's not a regression or a bug, I guess.

> - noting that MOVE_RATIO
> will f.i. affect inlining and sra decisions.

I know.  The SPEC results convince me it's a good idea overall,
considering all that.  Do you think additional testing is needed?
If so, what?