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From: Andreas Schwab <schwab@suse.de>
To: James Antill <james@and.org>
Cc: Andi Kleen <ak@suse.de>, linux-kernel@vger.kernel.org
Subject: Re: Linux 2.4.10-pre11 -- __builtin_expect
Date: 27 Sep 2001 18:28:08 +0200	[thread overview]
Message-ID: <jeofnwsinb.fsf@sykes.suse.de> (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> <nnvgi4prod.fsf@code.and.org>
In-Reply-To: <nnvgi4prod.fsf@code.and.org> (James Antill's message of "27 Sep 2001 11:41:22 -0400")

James Antill <james@and.org> writes:

|> 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.

You're right, seems like __builtin_expect is really only defined for pure
boolean values.

Andreas.

-- 
Andreas Schwab                                  "And now for something
Andreas.Schwab@suse.de				completely different."
SuSE Labs, SuSE GmbH, Schanzäckerstr. 10, D-90443 Nürnberg
Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5

  reply	other threads:[~2001-09-27 16:28 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
2001-09-27 16:28                 ` Andreas Schwab [this message]
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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