From: Albert Cahalan <albert@users.sf.net>
To: Andrew Morton OSDL <akpm@osdl.org>
Cc: Albert Cahalan <albert@users.sourceforge.net>,
willy@w.ods.org, chip@pobox.com,
linux-kernel mailing list <linux-kernel@vger.kernel.org>,
davem@redhat.com
Subject: Re: [PATCH] 2.4.22pre10: {,un}likely_p() macros for pointers
Date: 11 Aug 2003 19:13:58 -0400 [thread overview]
Message-ID: <1060643637.949.228.camel@cube> (raw)
In-Reply-To: <20030811115547.38b78b8e.akpm@osdl.org>
On Mon, 2003-08-11 at 14:55, Andrew Morton wrote:
> Albert Cahalan <albert@users.sourceforge.net> wrote:
> >
> > -#define likely(x) __builtin_expect((x),1)
> > -#define unlikely(x) __builtin_expect((x),0)
> > +#define likely(x) __builtin_expect(!!(x),1)
> > +#define unlikely(x) __builtin_expect(!!(x),0)
>
> Odd. I thought we fixed that ages ago.
>
> Being a simple soul, I prefer __builtin_expect((x) != 0, 1).
That's much harder to read. The !! is a nice
neat idiom. The other way requires a bit of thought.
(is that == or !=, a 0 or 1, and what does that
compute to?)
The !! is visually distinctive. It has only one use.
When you see it, you instantly know that a value is
being converted to the pure boolean form.
next prev parent reply other threads:[~2003-08-11 23:24 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-10 4:03 [PATCH] 2.4.22pre10: {,un}likely_p() macros for pointers Albert Cahalan
2003-08-10 7:29 ` Willy Tarreau
2003-08-10 8:02 ` Willy Tarreau
2003-08-11 1:23 ` Chip Salzenberg
2003-08-11 2:09 ` Jamie Lokier
2003-08-11 2:39 ` Chip Salzenberg
2003-08-11 4:02 ` Albert Cahalan
2003-08-11 4:30 ` Jamie Lokier
2003-08-11 5:30 ` Willy Tarreau
2003-08-11 5:42 ` Jamie Lokier
2003-08-11 13:09 ` Albert Cahalan
2003-08-11 18:55 ` Andrew Morton
2003-08-11 23:13 ` Albert Cahalan [this message]
2003-08-13 19:42 ` Jamie Lokier
2003-08-11 4:55 ` Jamie Lokier
2003-08-11 5:26 ` Willy Tarreau
2003-08-11 5:38 ` Jamie Lokier
-- strict thread matches above, loose matches on Subject: below --
2003-08-05 12:44 Albert Cahalan
2003-08-09 0:21 ` Jamie Lokier
2003-08-09 8:13 ` Willy Tarreau
2003-08-09 8:51 ` David S. Miller
2003-08-09 9:36 ` Jamie Lokier
2003-08-09 10:10 ` Herbert Xu
2003-08-09 10:42 ` Alan Cox
2003-08-09 16:23 ` Jamie Lokier
2003-08-04 17:06 Chip Salzenberg
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