Mailing List Archive

optimization flags
What level of optimizations flags are recommended?

Is the advice regarding flags for i386 in the official documentation
appropriate?
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Re: optimization flags [ In reply to ]
I use the flags from the Safe_Cflags article on the wiki (
http://gentoo-wiki.com/Safe_Cflag ). So far they haven't caused me any
headaches.

CHOST="alpha-unknown-linux-gnu"
CFLAGS="-mieee -O2 -mcpu=ev56 -pipe"
CXXFLAGS="${CFLAGS}"

> What level of optimizations flags are recommended?
On all of the Gentoo systems I've set up I've used -O2. I use it over
-O3 for a number of reasons. One, I cannot tell the difference in
terms of speed between something that is compiled with -O2 vs. -O3.
Two, emerge times are longer if you use -O3. Three, sometimes using
too many optimizations screws things up. (see
http://bugs.gentoo.org/74072 ).

-Thomas

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