On Fri, Jun 10, 2016 at 4:48 PM, Rowley, Timothy O <timothy.o.row...@intel.com> wrote: > >> On Jun 10, 2016, at 3:37 PM, Rowley, Timothy O <timothy.o.row...@intel.com> >> wrote: >> >>> >>> On Jun 10, 2016, at 3:01 PM, Emil Velikov <emil.l.veli...@gmail.com> wrote: >>> >>> On 10 June 2016 at 20:43, Tim Rowley <timothy.o.row...@intel.com> wrote: >>>> Previously used core-avx-i was for ivybridge; >>>> corei7-avx allows sandybridge. >>> Which GCC version was required by the previous and which by the >>> current version ? >> >> Both options work back to gcc 4.8.x. I picked the wrong architecture flag >> when setting up the build system initially. >> >>>> --- >>>> src/gallium/drivers/swr/Makefile.am | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/src/gallium/drivers/swr/Makefile.am >>>> b/src/gallium/drivers/swr/Makefile.am >>>> index d211f2e..8156cf2 100644 >>>> --- a/src/gallium/drivers/swr/Makefile.am >>>> +++ b/src/gallium/drivers/swr/Makefile.am >>>> @@ -124,7 +124,7 @@ COMMON_LDFLAGS = \ >>>> lib_LTLIBRARIES = libswrAVX.la libswrAVX2.la >>>> >>>> libswrAVX_la_CXXFLAGS = \ >>>> - -march=core-avx-i \ >>>> + -march=corei7-avx \ >>> I'm likely missing something but neither one seems listed in the 5.4 >>> [1] and 6.1 [2] manual. Should we be using one that's officially >>> supported ? >> >> According to Chuck Atkins, while the older options aren’t documented >> anymore, they still work on gcc 5.x and 6.x. >> >> Another possibility which Ilia also mentioned was to use feature flags >> instead which have stayed consistent between gcc versions, i.e. “-mavx” and >> “-mavx2 -mfma -mf16c” respectively for the avx and avx2 configurations. Not >> too opposed to this except that we’ve had extensive testing with the -march >> flags and changing the build configuration during the release candidate >> stage seems a bit late. > > Another thought along these lines - since the swr code makes heavy use of > intrinsics, we would like to have the code optimized as best as possible to > the target architecture (or at least, the baseline architecture which > introduces AVX and AVX2 respectively), which is best done with the -march > flags.
Actually it's best done with -mtune flags. -march, of course, also sets mtune. (But you can override it later.) -ilia _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
