linux-kernel - Re: question oh macros and gcc's intelligence

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Message-ID: <20110317090641.GA22723@ZenIV.linux.org.uk>
Date:	Thu, 17 Mar 2011 09:06:41 +0000
From:	Al Viro <viro@...IV.linux.org.uk>
To:	Oliver Neukum <oneukum@...e.de>
Cc:	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: question oh macros and gcc's intelligence

On Thu, Mar 17, 2011 at 08:48:57AM +0100, Oliver Neukum wrote:
> Hi,
> 
> if I write:
> 
> if (le16_to_cpu(p) == CONST) a();
> 
> is gcc smart enough to convert CONST to le16 and do
> a simple comparison?

On little-endian - certainly, on big-endian - forget it.
	if (p == cpu_to_le16(CONST))
would obviously work on any architecture and yes, it would be a comparison
with compile-time constant.
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