linux-kernel - Re: [PATCH 2/2] kernel/{exit.c, signal.c, power/process.c}: replace !likely(x) by likely(!x)

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:	Sat, 16 Feb 2008 19:56:49 -0800
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Rene Herman <rene.herman@...access.nl>
CC:	Roel Kluin <12o3l@...cali.nl>, lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] kernel/{exit.c, signal.c, power/process.c}: replace
 !likely(x) by likely(!x)

Rene Herman wrote:
> On 16-02-08 20:01, H. Peter Anvin wrote:
>> Roel Kluin wrote:
>>> Not entirely sure who to send this to
>>> ---
>>> Replace !likely(x) by likely(!x)
>>
>> Whoa...
>>
>> Are you sure this is correct?
>>
>> !likely(x) is equivalent to unlikely(!x)
> 
> Not with respect to its value I believe? likely(x) == !!(x), and 
> unlikely(!x) == !!(!x) = !x, so conditions work out differently?

You missed one ! sign:

!likely(x) == !!!(x) == unlikely(!x) == !!(!(x))

	-hpa
--
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/