Date: Sat, 12 May 2001 08:34:25 +0300
From: "Eli Zaretskii" <eliz AT is DOT elta DOT co DOT il>
Sender: halo1 AT zahav DOT net DOT il
To: "Patrick Mitran" <pmitran AT tsp DOT ece DOT mcgill DOT ca>
Message-Id: <7458-Sat12May2001083424+0300-eliz@is.elta.co.il>
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CC: djgpp AT delorie DOT com
In-reply-to: <2rVK6.20535$z01.3117219@carnaval.risq.qc.ca>
	(pmitran AT tsp DOT ece DOT mcgill DOT ca)
Subject: Re: -O6 optimizations
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> From: "Patrick Mitran" <pmitran AT tsp DOT ece DOT mcgill DOT ca>
> Newsgroups: comp.os.msdos.djgpp
> Date: Fri, 11 May 2001 17:37:02 GMT
> 
> I'm using gcc 2.95.3. I was wondering where I could get a list of all the
> optimizations that are turned on by -O6.

"-O6" is the same as "-O3".  The GCC manual explains what
optimizations are turned on by each -On option.  I agree that this
section in the GCC docs needs work, but that's the best you can
currently have without looking at the sources (which you should do if
you really want all the gory details).

"-O6" only does some real work in the PGCC variant of the compiler,
which is not what you have (and which is not on the main branch of the
GCC development anyway).

> Also, do I have to add the -mpentium switch too or is this
> inclused in -O6.

AFAIK, architecture-specific switches such as -mpentium are not
included in any optimization switches.

> I've read the FAQ, but it seems a bit ambiguous about what suggested
> switches to use for maximum optimization.

The FAQ must be at least a bit ambiguous, because the optimal
combination of switches changes with each GCC release.  If the FAQ
would say something very specific, it would become outdated very
quickly.  I don't have the necessary resources to release a new
version of the FAQ each tiem a new GCC version is out ;-)