On Tue, Jun 14, 2011 at 3:41 PM, Fang, Changpeng <changpeng.f...@amd.com> wrote: >>It probably should go to the 4.6 branch as well. > > H.J. Lu's original patch that splits unaligned load and store was checked in > gcc 4.7 > trunk. We found that, splitting unaligned store is beneficial to bdver1, > splitting unaligned > load degrades cfp2006 by 1.3% in geomean on Bulldozer. As a result, we > suggest putting > unaligned store splitting (H.J. original patch + this one) back to 4.6 branch. > > >Note that I find the >>X86_TUNE_AVX256_SPLIT_UNALIGNED_LOAD_OPTIMAL odd, >>why not call it simply X86_TUNE_AVX256_SPLIT_UNALIGNED_LOAD? > > AVX256_SPLIT_UNALIGNED_LOAD has already been used for the flag: > -mavx256-split-unaligned-load, and we intend to keep that flag for > performance tuning. > As a result, we put _OPTIMAL (or _BENEFICAL) at the end for default setting. > > >>I'll defer to x86 maintainers for approval. > > So, is it OK to commit this patch to trunk, and H.J's original patch + this > to 4.6 branch? > >
I have no problems on -mtune=Bulldozer. But I object -mtune=generic change and did suggest a different approach for -mtune=generic. -- H.J.
