From: Albert Cahalan <albert@users.sf.net>
To: Jamie Lokier <jamie@shareable.org>
Cc: Andrew Morton <akpm@digeo.com>,
akpm@osdl.org, Willy Tarreau <willy@w.ods.org>,
Chip Salzenberg <chip@pobox.com>,
Albert Cahalan <albert@users.sourceforge.net>,
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 09:09:59 -0400 [thread overview]
Message-ID: <1060607398.948.213.camel@cube> (raw)
In-Reply-To: <20030811054209.GN10446@mail.jlokier.co.uk>
On Mon, 2003-08-11 at 01:42, Jamie Lokier wrote:
> Willy Tarreau wrote:
> > So in any case, the !!(x) construct should be valid.
>
> Yes, either of these is fine for pointers and integers alike:
>
> #define likely(x) __builtin_expect ((x) != 0, 1)
> #define unlikely(x) __builtin_expect ((x) != 0, 0)
>
> #define likely(x) __builtin_expect (!!(x), 1)
> #define unlikely(x) __builtin_expect (!!(x), 0)
Choosing the more familiar idiom for booleanizing a value, here we go:
diff -Naurd old/include/linux/compiler.h new/include/linux/compiler.h
--- old/include/linux/compiler.h 2003-08-11 09:02:18.000000000 -0400
+++ new/include/linux/compiler.h 2003-08-11 09:04:58.000000000 -0400
@@ -24,8 +24,8 @@
#define __builtin_expect(x, expected_value) (x)
#endif
-#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)
/*
* Allow us to mark functions as 'deprecated' and have gcc emit a nice
next prev parent reply other threads:[~2003-08-11 13:20 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 [this message]
2003-08-11 18:55 ` Andrew Morton
2003-08-11 23:13 ` Albert Cahalan
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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