Florian Philipp wrote: > Am Freitag 20 Juli 2007 20:16 schrieb Kenneth Prugh: >> Andrew Gaydenko wrote: >>> I have noticed, the official portage tree has included gcc 4.2. Now for >>> Core 2 Duo CPU (amd64 Gentoo arch) I use in make.conf file: >>> >>> CFLAGS="-O2 -march=nocona -pipe" >>> >>> gcc' changelog has this note: >>> >>> -------------------- >>> ... >>> IA-32/x86-64 >>> >>> * -mtune=generic can now be used to generate code running well on >>> common x86 chips. This includes AMD Athlon, AMD Opteron, Intel Pentium-M, >>> Intel Pentium 4 and Intel Core 2. >>> * -mtune=native and -march=native will produce code optimized for the >>> host architecture as detected using the cpuid instruction. >>> ... >>> -------------------- >>> >>> The question is: must I replace '-march=nocona' with '-mtune=native and >>> -march=native'? >> I have a Core2 Duo E6600 and use these CFLAGS with GCC 4.2: >> >> CFLAGS="-Os -march=native -mtune=native -fomit-frame-pointer -pipe -mmmx >> -msse2 -msse3" >> >> Native works fine here. > > I don't think that you need -msse3 -msse2 and -mmmx because -march takes care > of that (refer to "man gcc", one notable exeption: -march=athlon64 does not > pull -msse3 in because not all Athlons support it). > -fomit-frame-pointer is unneccessary on AMD64 (refer to "man gcc", again).
Yeah I wasn't exactly positive if it did pull everything in, and specifying specifically can't really hurt at all as long as you know it's supported with your cpu. -- Kenneth Prugh - Ken69267 Gentoo AMD64 Arch Tester
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