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Re: gcc 3.4.1 and CPU optimization
Helo!
I read very carefully gcc docs and some infos on the net.
Old -mcpu= -m386 -m486 -pentium -mpentiumpro are repalced by new -mtune=
The -mmx -msse -m3dnow are included in -march=
The -mtune is included in -march=
So -march= have all optimizations included.
Every next option provided in commandline overwrites the one used before (e.g.
if specified -march=i586 -march=athlon-xp compilation will be made for
athlon-xp).
The ./configure CFLAGS="-march=athlon-xp" places -march=athlon-xp at the end
of gcc parameter list so all optimizations used before are overwritten by
-march=athlon-xp.
Is it true or my pure imagination?
If script generated -march=i586 -mtune=i686 and I add
CFLAGS="-march=athlon-xp" parameter, the compilation will be for athlon-xp
and -mtune=i686 will not be used?
greetings,
Zbigniew