On Wed, Mar 01, 2006 at 03:06:46PM -0800, Mark Mitchell wrote: > H. J. Lu wrote: > > > Here are diffs of "-O2 -mtune=nocona -ffast-math" vs > > "-O2 -mtune=generic -ffast-math" on Nocona: > > A 1.5% performance improvement, while certainly significant for some > users, is not worth taking any serious risks on a release branch. The
You are comparing apply with orange. If a user uses -O2, he/she will see much more than that. > > The first step is to address regressions on the mainline. I have not > myself verified the claim, but there has been a suggestion that there is > at least one open regression due to the patch. If there are any known > regressions from the patch, it's certainly not eligible for a backport. I am only aware of http://gcc.gnu.org/bugzilla/show_bug.cgi?id=26146 and I have a patch. BTW, I don't think it is a real regression, just a latent bug. I doubt # configure i[456]86-pc-solaris2.10 # onfigure --with-cpu=i[3456]86 i386-pc-solaris2.10 had ever worked. In any case, please CC me any -mtune=generic patch. H.J.
