Date: Mon, 13 Jan 2003 17:37:48 -0500 (EST)
Message-Id: <200301132237.h0DMbm1328427@saturn.cs.uml.edu>
From: "Albert D. Cahalan" <acahalan@cs.uml.edu>
To: linux-kernel@vger.kernel.org
Cc: matti.aarnio@zmailer.org
Subject: Re: any chance of 2.6.0-test*?
Sender: linux-kernel-owner@vger.kernel.org


Matti Aarnio writes:

> Advanced optimizer hinting features, like unlikely() attribute
> are very new in (this) compiler, and while they in theory move the
> "unlikely" codes out of the fast-path, such things have been buggy
> in the past, and we are worried of bug effects... 

I've been wondering about this as the goto-thread spewed by.

As I recall, gcc recently started moving basic blocks around.
This destroyed most of the careful goto-based optimizations.
Now we're supposed to use likely() and unlikely() instead.

Hmmm?

BTW, what I'd like is a way to change optimization settings
on a per-function or even per-block basis. Telling gcc to
unroll a specific loop or pack a function into a tiny space
would be really cool.   __attribute__((__opt__("-Os")))
I could go for an "assume default case can't happen" too.
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