gcc optimization [was: Problems with the gimp1.2.3 n gtk+]

Tim Holterhus lfs at holterhus.com
Tue Nov 12 17:51:56 PST 2002

On Wednesday 13. November 2002 01:28, James Drabb wrote:
> On Wed, 13 Nov 2002 00:20:29 +0100
> I compile most software with:
> -O2 -fomit-frame-pointer -march=pentium3 -w
> So far this has proven very stable.  I have compiled all software
> past the base LFS 4.0 with the flags above except for X.  The system
> response time seems nice and snappy (well for a P III 800).  Maybe
> you could redo glib/gtk+-2.x with similar cflags and then redo gimp?
> In my experience -O2 produces the best all around code.  -O3 does
> some "optimizations" that might not fit well for every application
> and also causes compilation time to increase.
> Jim Drabb
> --
> ---------------------------------------------------------------
> Those who would sacrifice freedom for security will get neither
> ---------------------------------------------------------------
> James Drabb JR
> Programmer Analyst
> Davenport, FL
> JDrabb at tampabay.rr.com

I recompiled gimp using "-O2 -march=i686 -fomit-frame-pointer" and it 
now works just fine. The Gimp is the first app that showed problems 
when compiled using "-O3".
All other apps & libs (except when explicitly mentioned in either the 
(b)lfs books or in the install docs) I compiled with cflags set to "-O3  
-march=i686 -fomit-frame-pointer". No major problems so far.

I have a PIII 800 (overclocked to 1 Ghz) and the compile times for 
various apps - compared to info I got from either here or other sources 
- seems to be rather long. Compiling kde from the current cvs on a PIII 
600 - I read - only takes about 7-8 hours (including qt-copy), while on 
my system it takes about 12-16 hours. I wonder wether there is still 
something fishy w/ my CFLAGS ...


As I said before, I never repeat myself.

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