On Wed, Mar 01, 2006 at 04:05:16PM -0800, H. J. Lu wrote: > 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.
I meant to say "comparing apple with orange". > > > > > 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. Let me rephrase, please CC me any -mtune=generic related bugs. H.J.
