[gentoo-amd64] Re: x86_64 optimization patches for glibc.

[Duncan <1i5t5.duncan@cox.net>]

netpython posted <3655f5d905072703096be71ed1@mail.gmail.com>, excerpted
below,  on Wed, 27 Jul 2005 10:09:35 +0000:

> Should i use -march=k8 or -march=athlon64 ? Or doesn't make any
> difference? My CPU is a AMD64 3000+

At this point, it makes absolutely no difference.  The two, along with
-march=opteron, and I think one or two other aliases, are internally set
to exactly the same thing in gcc.

There's a small chance that at some point in the future the hardware paths
of the current aliases will diverge enough to make splitting the alias a
possibility, but practically speaking, even if that /were/ to happen, the
new diverged version would very likely get a different name, so as to
preserve backward compatibility for all those who set their configuration
when they were all aliases.  Thus, the chance of there actually being a
difference between what is now treated exactly the same, is in reality,
/very/ small, a small chance on a small chance.  Odds of winning the
lottery or dieing in a car accident are likely far higher.

Here, I use -march=k8, simply because "k8" is a distinctive and short
enough string, it's easy to pick out in moving text, as the compile output
scrolls by, thus making it easier for me to verify my CFLAGS as part of
the settings fed to gcc as they fly by.  Other than that, it's entirely
arbitrary.

-- 
Duncan - List replies preferred.   No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master."  Richard Stallman in
http://www.linuxdevcenter.com/pub/a/linux/2004/12/22/rms_interview.html


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