From mboxrd@z Thu Jan  1 00:00:00 1970
From: Nikita Danilov <nikita@clusterfs.com>
Date: Wed, 30 Aug 2006 16:11:44 +0000
Subject: Re: [RFC][PATCH 01/10] put alignment macros in align.h
Message-Id: <17653.47296.222332.231821@gargle.gargle.HOWL>
List-Id: <linux-ia64.vger.kernel.org>
References: <20060829201934.A5363374@localhost.localdomain>
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To: linux-ia64@vger.kernel.org

Dave Hansen writes:
 > 

[...]

 > + */
 > +#ifndef __ASSEMBLY__
 > +#define ALIGN(x,a) (((x)+(a)-1)&~((a)-1))

This evaluates (a) twice. While in all existing call-sites (a) is
probably a constant, it's still safer to do

#define ALIGN(x,a) ({ typeof(a) __a = (a); (((x) + __a - 1) & ~(__a - 1)); })

in a generic macro and rely on compiler to optimize temporary variable
out.

Nikita.