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Date:      Tue, 8 May 2001 03:10:01 -0700
From:      Kris Kennaway <kris@obsecurity.org>
To:        Juha Saarinen <juha@saarinen.org>
Cc:        Jordan Hubbard <jkh@osd.bsdi.com>, dmmiller@cvzoom.net, msmith@FreeBSD.ORG, kris@obsecurity.org, nuno.mailinglists@pt-quorum.com, guilherme@nortenet.pt, freebsd-stable@FreeBSD.ORG
Subject:   Re: CFLAGS Optimization
Message-ID:  <20010508031001.A91590@xor.obsecurity.org>
In-Reply-To: <KPECIILENDDLPCNIMLOFCENOCDAA.juha@saarinen.org>; from juha@saarinen.org on Tue, May 08, 2001 at 10:02:31PM %2B1200
References:  <20010508012916Q.jkh@osd.bsdi.com> <KPECIILENDDLPCNIMLOFCENOCDAA.juha@saarinen.org>

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On Tue, May 08, 2001 at 10:02:31PM +1200, Juha Saarinen wrote:

> Yes, but you must agree that this is a poorly documented area. If you look
> at the GCC documentation, it says that "optflag -x produces better code f=
or
> processor/architecture Y". It's not so easy for people to work out which
> bits of the GCC documentation are bogus and which are not.

It's well documented in /etc/defaults/make.conf

# CFLAGS controls the compiler settings used when compiling C code.
# Note that optimization settings above -O (-O2, ...) are not recommended
# or supported for compiling the world or the kernel - please revert any
# nonstandard optimization settings to "-O" before submitting bug reports
# to the developers.
# Note also that at this time the -O2 setting is known to produce BROKEN
# CODE on the Alpha platform.

> If GCC optimisations are unequivocally bad, ie. not useful in any sense of
> the word, it might be an idea to patch the FreeBSD GCC so that it's not
> possible to use any optflags.

As already stated several times, they're not unequivocally bad;
they're in fact very useful if used in controlled circumstances,
i.e. where you test that the thing you're compiling still works as it
should.  They're bad when used unequivocally.

> :: The next place this subject usually goes is "why don't we use
> :: something other than gcc?"  Any and all actual attempts to do so is
> :: left as an exercise for the reader.  Like riding a unicycle, it's not
> :: as easy as it looks.
>=20
> Well, I never found riding a unicycle that hard, but I guess it's an
> individual experience and all that. ;-)
>=20
> It wouldn't hurt, I don't think, to have an alternative to GCC.

*sigh*

Kris

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