Message-Id: <3.0.32.19980321194319.006a9a7c@uniserv.uniplan.it>
Date: Sat, 21 Mar 1998 19:47:45 +0100
To: djgpp AT delorie DOT com
From: Angelo Pesce <us0082 AT uniserv DOT uniplan DOT it>
Subject: Re: DJ: Compiler Optimizations
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At 09.50 21/03/98 -0500, you wrote:
>>John M. Aldrich wrote:
>                                                                             
>>Overall, the best optimization level for non-PGCC is -O2.  -O3 tries to
    
>>perform inlining, which sometimes speeds code up but also occasionally 
>>slows it down.  -m486, -ffast-math, and -fomit-frame-pointer are also
    
>>good optimization flags.  The gcc docs list all of them.
    
> 
>Ok, well you've been an incredible help. My compiler is already well over 4x 
>its previous speed.  I can't find the -m486 flag.  What menu is it under
>in rhide?
-m486 should be a default option on standard gcc. With pgcc the default is
-mpentium. You can also directly add compiler switches in rhide using the
"additional compiler options" dialog. You should download pgcc too, it's
much faster than standard gcc. -fomit-frame-pointer is VERY useful you
should try -funroll-all-loops and -fstrength-reduce too. With pgcc use -O6
instead of -O3 or -O2