On Fri, Dec 29, 2017 at 03:49:59AM -0600, William Harrington wrote:
> On Thu, 28 Dec 2017 22:21:08 -0600
> Bruce Dubbs <[email protected]> wrote:
>
> > > make 'AR_FLAGS=' 'CC_FOR_BUILD=' 'CFLAGS=-O3 -fomit-frame-pointer \
> > > -fstrict-aliasing -ffast-math -march=corei7-avx -Wall \
> > > -fexceptions' 'CXXFLAGS=-g -O2'
>
> Use -march=native next time.
>
Also:
· 'no optimizations' isn't really true - setting anything in
CFLAGS (except perhaps -O2 and adding/removing -g) is a form of
optimization
· -ffast-math might give problems in a testsuite if a package is not
expecting it (somewhat unlikely, but then most people don't run most
testsuites)
· and lower optimization for C++ ?
In general, *where a package respects CFLAGS, CXXFLAGS* (not all of
them do) the gains or losses from adding any particular option need
to be measured several times before deciding if that option is
worthwhile *on that specific machine and that package.
OTOH, exploring the options to find out what is beneficial on the
current machine can be an interesting, and occasionally useful, line
of study - but it does get in the way of building/updating packages,
and over time (newer versions of gcc) the benefits/losses can
change. So, your system, your rules, your choices ;-)
ĸen
--
Truth, in front of her huge walk-in wardrobe, selected black leather
boots with stiletto heels for such a barefaced truth.
- Unseen Academicals
--
http://lists.linuxfromscratch.org/listinfo/blfs-support
FAQ: http://www.linuxfromscratch.org/blfs/faq.html
Unsubscribe: See the above information page
