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Reply-To: efremov@linux.com
Subject: Re: [PATCH] scripts: coccinelle: check for !(un)?likely usage
To:     Julia Lawall <julia.lawall@lip6.fr>
Cc:     Joe Perches <joe@perches.com>, cocci@systeme.lip6.fr,
        linux-kernel@vger.kernel.org,
        Gilles Muller <Gilles.Muller@lip6.fr>,
        Nicolas Palix <nicolas.palix@imag.fr>,
        Michal Marek <michal.lkml@markovi.net>
References: <20190825130536.14683-1-efremov@linux.com>
 <b5bae2981e27d133b61d99b08ee60244bf7aabe3.camel@perches.com>
 <88f6e48e-1230-9488-a973-397f4e6dfbb5@linux.com>
 <4E9DDF9E-C883-44F0-A3F4-CD49284DB60D@lip6.fr>
From:   Denis Efremov <efremov@linux.com>
Message-ID: <496b3d09-47a2-3836-2899-d964267993d3@linux.com>
Date:   Wed, 28 Aug 2019 15:41:43 +0300
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> 
> 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,
Denis