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Re: [BusyBox] Re: Long term code compactness regression



----- Original Message -----
From: "Jan Hubicka" <jh@suse.cz>
To: "Tim Prince" <tprince@computer.org>
Cc: "Paolo Carlini" <pcarlini@unitus.it>; "David Schleef"
<ds@schleef.org>; <gcc@gcc.gnu.org>
Sent: Sunday, October 28, 2001 9:08 AM
Subject: Re: [BusyBox] Re: Long term code compactness regression


> > So, will we retain the option of setting an aligned stack along
with -Os
> Not.
> currently the mainline contains patch to default stack alignment to 2
if
> -Os is present I am not quite happy about.
> You can still pass -Os and overwrite the alignment
by -mpreferred-stack-bodary=4
> > ?  On most of my applications, -Os together with -funroll-loops and
> > aligned data is the fastest running combination for ia32, by a large
> > margin.
> Do you have any idea why this happends? We should really keep -O2
faster
> than -Os in most cases.
> I've done some work on the mainline to avoid code bloat in -O2 mode, so
> maybe the score is better now.
>
> Honza

I checked this morning, with last week's gcc-3.1 snapshot.  A few cases
with g77 have slowed down in recent weeks.  The worst examples of
slowness with g77 -O2 involve the generation of redundant pointers, as we
have discussed before.  I see -Os faster than -O2 in the same tests
on -msse2 and on -march=pentiumpro.


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