Re: inliner in gcc-3.1

[Kurt Garloff <garloff@suse.de>]

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Hi Gerald,

thanks for your testing!

On Thu, Apr 25, 2002 at 09:18:24AM +0200, Gerald Pfeifer wrote:
> On Wed, 24 Apr 2002, Kurt Garloff wrote:
> > I was browsing the gcc ML archives (I'm not subscribed) and found
> > that the inliner may still not be tuned optimally in gcc-3.1.
> > [...]
> > * I have adapted by inliner patch (v3) to 3.1 (CVS 2002-04-23)
> >   and it still works ...
> Bad news: This patch increases compilation time (for DLV, the package
> I've been using to test performance) quite a bit:
> 
>   2.95.3			 4:01	4430752
>   3.0				23:54	6295044
>   3.0.3				 3:58	3948444
>   3.1-20020422			 4:38	3996096
>   3.1-20020424+kurtpatch	 5:35   4102432
>   3.1-20020422+limit=800	 6:37	4177344

OK, so from compile time and binary size, kurtv3 is somewhere around
finline-limit=700 ...

[...]
> And excellent news: This patch really improves the quality of the
> generated code, and quite significantly so in several cases (much
> more than those 3% you claimed)!

Amazing. I just also compared to your -800 results and we still win
significantly more than half of the benchmarks.

[...]
> This would be very nice to have in GCC 3.1, if it were not for the longer
> compile time.

One could try with -finline-limit-540 or so and see whether we can similar
compilation times as 3.1 and still win benchmarks. If yes, it could be an
option for 3.1 to incorporate the patch and lower the default inline-limit.

Regards,
-- 
Kurt Garloff  <garloff@suse.de>                          Eindhoven, NL
GPG key: See mail header, key servers         Linux kernel development
SuSE Linux AG, Nuernberg, DE                            SCSI, Security

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