linux-kernel - Re: [Cbe-oss-dev] [PATCH 1/3] Fix Unlikely(x) == y

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 18 Feb 2008 11:22:18 -0800
From:	"Andrew Pinski" <pinskia@...il.com>
To:	"Geert Uytterhoeven" <Geert.Uytterhoeven@...ycom.com>
Cc:	"Adrian Bunk" <bunk@...nel.org>, "Roel Kluin" <12o3l@...cali.nl>,
	lkml <linux-kernel@...r.kernel.org>, cbe-oss-dev@...abs.org,
	linuxppc-dev@...abs.org, "Willy Tarreau" <w@....eu>,
	"Arjan van de Ven" <arjan@...radead.org>
Subject: Re: [Cbe-oss-dev] [PATCH 1/3] Fix Unlikely(x) == y

On Feb 18, 2008 6:01 AM, Geert Uytterhoeven
<Geert.Uytterhoeven@...ycom.com> wrote:
> > This means it generates faster code with a current gcc for your platform.
> >
> > But a future gcc might e.g. replace the whole loop with a division
> > (gcc SVN head (that will soon become gcc 4.3) already does
> > transformations like replacing loops with divisions [1]).

Yes but the issue is one optimization inside GCC does not take into
account the probability in one case.

And really there is a bug in the linux kernel for not implementing the
long long divide function (or really using libgcc) but that is a
different story and is part of the issue there anyways.

-- Pinski
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/