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Re: GCC 4.1.0 Released


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.


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