------- Comment #5 from hjl dot tools at gmail dot com 2010-09-01 16:37 ------- (In reply to comment #4) > (In reply to comment #3) > > (In reply to comment #2) > > > gcc-4.5 is still hardmasked downstream in Gentoo, then, I am unsure about > > > installing it :-/, are you sure this bug could be solved in 4.5* ? > > > > > > > 1. -march=native is changed in gcc 4.5. > > Will try then with 4.5.1 (4.5.2 is still not available on Gentoo) > > > 2. Your cpu is Core. > > 3. -mtune=generic generates the fastest code for Core. > > 4. Prescott and Core have the same instruction set. > > Is -mtune=generic better than -mtune=prescott? "man gcc" looks to suggest last > one would be better: > If you know the CPU on which your code will run, then you should use the > corresponding -mtune option instead of -mtune=generic. > >
-mtune=generic is the best tuning option for Intel processors, regardless whatever gcc manual says. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45483