Salut René, Le 18 mars 2014 à 10:44, René J.V. Bertin <rjvber...@gmail.com> a écrit :
> On Tuesday March 18 2014 09:43:57 Vincent Habchi wrote: >> If you want to use the -march=native switch, use Clang instead (LLVM-AS >> handles new extensions correctly). >> > > Or use -march=native -no-avx , or simply -march=core2 if you insist on having > AVX. -march=core2 precisely avoids AVX (AVX was introduced on the next ‘tock’, Nehalem). You can still get SSE4.2 with -msse4.2 with the old Apple ‘as’ though. > Note that when your code isn't optimised for using SIMD instructions you'll > likely see very little benefit from using the full instruction set. In fact, > in the testing I did I got better floating point performance using gcc 4.7 > with -march=core2 than with clang 3.3 with -march=native . I *think* clang > still doesn't have a (good) auto-vectorisation engine, while gcc's has become > quite impressive IMHO. That’s not what the latest Phoronix tests seemed to point out (but with clang 3.4). http://www.phoronix.com/scan.php?page=article&item=llvm34_gcc49_compilers&num=1 Bonne journée ! Vincent _______________________________________________ macports-users mailing list macports-users@lists.macosforge.org https://lists.macosforge.org/mailman/listinfo/macports-users