From owner-freebsd-hackers@FreeBSD.ORG  Tue Mar 12 07:52:12 2013
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Delivered-To: freebsd-hackers@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 by hub.freebsd.org (Postfix) with ESMTP id 65E4FE7D;
 Tue, 12 Mar 2013 07:52:12 +0000 (UTC) (envelope-from dim@freebsd.org)
Received: from tensor.andric.com (tensor.andric.com
 [IPv6:2001:7b8:3a7:1:2d0:b7ff:fea0:8c26])
 by mx1.freebsd.org (Postfix) with ESMTP id 218B8EB7;
 Tue, 12 Mar 2013 07:52:12 +0000 (UTC)
Received: from [IPv6:2001:7b8:3a7::5090:4bd6:bcf8:9b4f] (unknown
 [IPv6:2001:7b8:3a7:0:5090:4bd6:bcf8:9b4f])
 (using TLSv1 with cipher AES128-SHA (128/128 bits))
 (No client certificate requested)
 by tensor.andric.com (Postfix) with ESMTPSA id 5CE305C44;
 Tue, 12 Mar 2013 08:52:10 +0100 (CET)
Content-Type: text/plain; charset=us-ascii
Mime-Version: 1.0 (Mac OS X Mail 6.2 \(1499\))
Subject: Re: clang - odd macro / conditional expansion behaviour?
From: Dimitry Andric <dim@freebsd.org>
In-Reply-To: <CAJ-Vmonn1m_AMiJbxfGDM+XrpfF+LKunSeoUWgkF9QVaMKf5ew@mail.gmail.com>
Date: Tue, 12 Mar 2013 08:52:09 +0100
Content-Transfer-Encoding: quoted-printable
Message-Id: <D4060110-61CB-49E3-9064-2A3F1FBAC27D@freebsd.org>
References: <CAJ-Vmonn1m_AMiJbxfGDM+XrpfF+LKunSeoUWgkF9QVaMKf5ew@mail.gmail.com>
To: Adrian Chadd <adrian@freebsd.org>
X-Mailer: Apple Mail (2.1499)
Cc: freebsd-hackers@freebsd.org, Joerg Sonnenberger <joerg@britannica.bec.de>
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.14
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
 <freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-hackers>, 
 <mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
 <mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 12 Mar 2013 07:52:12 -0000

On Mar 12, 2013, at 04:17 , Adrian Chadd <adrian@freebsd.org> wrote:
> In file included from
> =
/usr/home/adrian/work/freebsd/ath/head/src/sys/modules/ath/../../contrib/s=
ys/dev/ath/ath_hal/ar9300/ar9300_eeprom.c:21:
> =
/usr/home/adrian/work/freebsd/ath/head/src/sys/modules/ath/../../contrib/s=
ys/dev/ath/ath_hal/ar9300/ar9300template_generic.h:107:3:
> error: implicit conversion from 'int' to
>      'u_int8_t' (aka 'unsigned char') changes value from -477 to 35
> [-Werror,-Wconstant-conversion]
>                FREQ2FBIN(2412, 1),
>                ^~~~~~~~~~~~~~~~~~
> =
/usr/home/adrian/work/freebsd/ath/head/src/sys/modules/ath/../../contrib/s=
ys/dev/ath/ath_hal/ar9300/ar9300eep.h:136:65:
> note: expanded from macro 'FREQ2FBIN'
>    (((y) =3D=3D HAL_FREQ_BAND_2GHZ) ? ((x) - 2300) : (((x) - 4800) / =
5))
>                                                   ~~~~~~~~~~~~~^~~

I cannot find the exact code you are referencing here, but I assume it =
is some sort of global initialization?  If so, this is most likely =
<http://llvm.org/bugs/show_bug.cgi?id=3D10030>, which has been =
languishing in LLVM's Bugzilla for a way too long time. :-(