optimization levels for 6-STABLE build{kernel,world}

[Oliver Fromme]

Marc G. Fournier <freebsd at 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

-- 
Oliver Fromme,  secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing
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