From: Denis Efremov <efremov@linux.com>
To: Julia Lawall <julia.lawall@lip6.fr>
Cc: Michal Marek <michal.lkml@markovi.net>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Nicolas Palix <nicolas.palix@imag.fr>,
linux-kernel@vger.kernel.org, Joe Perches <joe@perches.com>,
cocci@systeme.lip6.fr
Subject: Re: [Cocci] [PATCH] scripts: coccinelle: check for !(un)?likely usage
Date: Wed, 28 Aug 2019 16:57:26 +0300 [thread overview]
Message-ID: <e48665b3-eeb6-a258-18bb-779e09313e40@linux.com> (raw)
In-Reply-To: <496b3d09-47a2-3836-2899-d964267993d3@linux.com>
On 8/28/19 3:41 PM, Denis Efremov wrote:
>
>>
>> As a human I am confused. Is !likely(x) equivalent to x or !x?
>>
>> Julia
>>
>
> As far as I could understand it:
>
> # define likely(x) __builtin_expect(!!(x), 1)
> !likely(x)
> !__builtin_expect(!!(x), 1)
> !((!!(x)) == 1)
> (!!(x)) != 1, since !! could result in 0 or 1
> (!!(x)) == 0
> !(!!(x))
> !!!(x)
> !(x)
>
Thanks Rasmus for the explanation, this should be:
!likely(x)
!__builtin_expect(!!(x), 1)
!(!!(x))
!!!(x)
!(x)
Denis
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next prev parent reply other threads:[~2019-08-28 13:57 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-25 13:05 [Cocci] [PATCH] scripts: coccinelle: check for !(un)?likely usage Denis Efremov
2019-08-25 15:30 ` Markus Elfring
2019-08-25 21:06 ` Denis Efremov
2019-08-25 15:30 ` Markus Elfring
2019-08-25 16:37 ` Joe Perches
2019-08-25 18:59 ` Denis Efremov
2019-08-25 19:19 ` Julia Lawall
2019-08-28 11:33 ` Rasmus Villemoes
2019-08-28 11:59 ` Joe Perches
2019-08-28 12:33 ` Denis Efremov
2019-08-28 12:33 ` Julia Lawall
2019-08-28 12:41 ` Denis Efremov
2019-08-28 13:57 ` Denis Efremov [this message]
2019-08-25 21:19 ` Denis Efremov
[not found] ` <20190901172403.GA1047@bug>
2019-09-01 17:39 ` Denis Efremov
2019-08-29 17:10 ` [Cocci] [PATCH v2] " Denis Efremov
2019-08-29 17:13 ` Denis Efremov
2019-08-30 0:42 ` Julia Lawall
2019-08-30 6:56 ` Denis Efremov
2019-08-30 8:06 ` Rasmus Villemoes
2019-08-29 20:07 ` Markus Elfring
2019-08-30 7:55 ` Markus Elfring
2019-09-06 20:19 ` Julia Lawall
2019-09-06 20:55 ` Denis Efremov
2019-09-07 8:05 ` [Cocci] [v2] " Markus Elfring
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