Date: Wed, 13 Sep 2006 12:17:15 +0300
From: Stefan Lambrev <stefan.lambrev@sun-fish.com>
To: freebsd-stable@FreeBSD.ORG
Subject: Re: optimization levels for 6-STABLE build{kernel,world}
Message-ID: <4507CC9B.60704@sun-fish.com>
In-Reply-To: <200609130905.k8D95idk062789@lurza.secnetix.de>
References: <200609130905.k8D95idk062789@lurza.secnetix.de>
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Hello, Oliver Fromme wrote: > Marc G. Fournier <freebsd@hub.org> wrote: > > What are ppl currently using for CFLAGS/COPTFLAGS in /etc/make.conf for > > building kernel/world? I know awhile back it wasn't recommended to go > > above -O2, for instance, but suspect that has changed ... ? > > The best optimization is probably to not override the > defaults at all, because they're already pretty optimal. > In fact, by overriding the defaults there's a good chance > to make things worse. :-) > > The default CFLAGS are "-O2 -pipe -fno-strict-aliasing". > Anything above -O2 isn't supported, and using -O2 without > -fno-strict-aliasing also isn't supported (and will create > broken code for some programs). A common mistake is to > specify CFLAGS="-O2 -pipe" and omit -fno-strict-aliasing. > That'll shot you in the foot sooner or later. > > Best regards > Oliver > > May be default flags have to be set here: /usr/src/share/examples/etc/make.conf ? I'm asking because in this file I read: # CFLAGS controls the compiler settings used when compiling C code. # Note that optimization settings other than -O and -O2 are not recommended # or supported for compiling the world or the kernel - please revert any # nonstandard optimization settings to "-O" or -O2 before submitting bug # reports without patches to the developers. # #CFLAGS= -O -pipe May be "-fno-strict-aliasing" have to be added here then ? -- Best Wishes, Stefan Lambrev ICQ# 24134177
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