Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756756Ab1DMO1l (ORCPT ); Wed, 13 Apr 2011 10:27:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:14966 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756638Ab1DMO1j (ORCPT ); Wed, 13 Apr 2011 10:27:39 -0400 Date: Wed, 13 Apr 2011 16:27:03 +0200 From: Oleg Nesterov To: Alexey Dobriyan Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, behlendorf1@llnl.gov Subject: Re: [PATCH] remove abs64() Message-ID: <20110413142703.GA1511@redhat.com> References: <20110412210045.GA19901@p183> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110412210045.GA19901@p183> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1267 Lines: 36 On 04/13, Alexey Dobriyan wrote: > > +#define abs(x) \ > +({ \ > + typeof(x) _x = (x); \ > + \ > + __builtin_choose_expr( \ > + __builtin_types_compatible_p(typeof(_x), signed char), \ > + (unsigned char)({ _x < 0 ? -_x : _x; }), \ > + __builtin_choose_expr( \ > + __builtin_types_compatible_p(typeof(_x), short), \ > + (unsigned short)({ _x < 0 ? -_x : _x; }), \ > + __builtin_choose_expr( \ > + __builtin_types_compatible_p(typeof(_x), int), \ > + (unsigned int)({ _x < 0 ? -_x : _x; }), \ > + __builtin_choose_expr( \ > + __builtin_types_compatible_p(typeof(_x), long), \ > + (unsigned long)({ _x < 0 ? -_x : _x; }), \ > + __builtin_choose_expr( \ > + __builtin_types_compatible_p(typeof(_x), long long), \ > + (unsigned long long)({ _x < 0 ? -_x : _x; }), \ > + _x))))); \ > +}) Personally I agree. But, we have some stupid users which do something like abs(u32_value) and expecting that abs() should treat this value as "signed". Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/