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From: James Antill <james@and.org>
To: Andreas Schwab <schwab@suse.de>
Cc: Andi Kleen <ak@suse.de>, linux-kernel@vger.kernel.org
Subject: Re: Linux 2.4.10-pre11 -- __builtin_expect
Date: 27 Sep 2001 11:41:22 -0400	[thread overview]
Message-ID: <nnvgi4prod.fsf@code.and.org> (raw)
In-Reply-To: <20010918031813.57E1062ABC@oscar.casa.dyndns.org.suse.lists.linux.kernel> <E15jBLy-0008UF-00@the-village.bc.nu.suse.lists.linux.kernel> <9o6j9l$461$1@cesium.transmeta.com.suse.lists.linux.kernel> <oup4rq0bwww.fsf_-_@pigdrop.muc.suse.de> <jeelp4rbtf.fsf@sykes.suse.de> <20010918143827.A16003@gruyere.muc.suse.de> <nn3d59qzho.fsf@code.and.org> <jezo7gu78f.fsf@sykes.suse.de>
In-Reply-To: <jezo7gu78f.fsf@sykes.suse.de>

Andreas Schwab <schwab@suse.de> writes:

> James Antill <james@and.org> writes:
> 
> |>  unlikely() also needs to be...
> |> 
> |> #define unlikely(x)  __builtin_expect(!(x), 1) 
> |> 
> |> ...or...
> |> 
> |> #define unlikely(x)  __builtin_expect(!!(x), 0) 
> 
> This is not needed, since only 0 is the likely value and !! does not
> change that.

 Yes it is, given the code...

struct blah *ptr = NULL;

if (unlikely(ptr))

...you'll get a warning from gcc because you are implicitly converting
from a pointer to a long.

-- 
# James Antill -- james@and.org
:0:
* ^From: .*james@and\.org
/dev/null

  reply	other threads:[~2001-09-27 15:41 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20010918031813.57E1062ABC@oscar.casa.dyndns.org.suse.lists.linux.kernel>
     [not found] ` <E15jBLy-0008UF-00@the-village.bc.nu.suse.lists.linux.kernel>
     [not found]   ` <9o6j9l$461$1@cesium.transmeta.com.suse.lists.linux.kernel>
2001-09-18 10:44     ` Andi Kleen
2001-09-18 11:13       ` Andreas Schwab
2001-09-18 12:38         ` Andi Kleen
2001-09-26 23:54           ` James Antill
2001-09-27 12:51             ` Andreas Schwab
2001-09-27 15:41               ` James Antill [this message]
2001-09-27 16:28                 ` Andreas Schwab
2001-10-04 18:52                   ` Richard Henderson
2001-10-08  6:17                     ` James Antill
2001-09-18 20:11         ` Horst von Brand

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