From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marc Lehmann <pcg@goof.com>
To: ronis@onsager.chem.mcgill.ca
Cc: egcs@cygnus.com
Subject: Re: [EGCS] Optimizations
Date: Wed, 10 Dec 1997 10:46:00 -0000
Message-id: <19971210184633.32470@cerebro.laendle>
References: <199712091751.MAA18879@ronispc.chem.mcgill.ca>
X-SW-Source: 1997-12/msg00598.html

> gcc -O6 -mpentium -fomit-frame-pointer -fexpensive-optimizations \
> >-ffast-math
> 
> To that, add:
>         -march=pentium
>         -fschedule-insns
>         -fschedule-insns2
>         -fregmove
>         -fdelayed-branch
> 
> According to the gcc info description, all the -f options are enabled
> (if supported) when -O2 (and I presume -O6) is specified.  Is this
> correct?  

no, you misread the info files. almost everything
except -finline-functions and -fomit-frame-pointer is enabled at -O2,
-O3 enables -finline-functions.

-fschedule-insns is a *loss* on x86 cpu's!

> -malign-double -malign-loops=0 -malign-jumps=0 -malign-functions=0\
> -mno-ieee-fp 
> 
> Are the -malign directives implied by -march=pentium? (they probably

on pgcc, yes, on egcs, no. the mno-ieee-fp is a bit buggy.

the -mpentium should be selected automatically when you compile
for i586-*-*, but I'm not exactly sure here.

> Is -mno-ieee-fp implied by -ffast-math?

no.

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      ---==---(_)__  __ ____  __       Marc Lehmann       +--
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