From owner-freebsd-toolchain@FreeBSD.ORG  Mon Sep 22 16:20:36 2014
Return-Path: <owner-freebsd-toolchain@FreeBSD.ORG>
Delivered-To: freebsd-toolchain@FreeBSD.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by hub.freebsd.org (Postfix) with ESMTPS id 4D110CE0;
 Mon, 22 Sep 2014 16:20:36 +0000 (UTC)
Received: from troutmask.apl.washington.edu (troutmask.apl.washington.edu
 [128.95.76.21])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (Client CN "troutmask.apl.washington.edu",
 Issuer "troutmask.apl.washington.edu" (not verified))
 by mx1.freebsd.org (Postfix) with ESMTPS id 0EACCFFC;
 Mon, 22 Sep 2014 16:20:36 +0000 (UTC)
Received: from troutmask.apl.washington.edu (localhost.apl.washington.edu
 [127.0.0.1])
 by troutmask.apl.washington.edu (8.14.9/8.14.9) with ESMTP id s8MGKYAH007965
 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO);
 Mon, 22 Sep 2014 09:20:34 -0700 (PDT)
 (envelope-from sgk@troutmask.apl.washington.edu)
Received: (from sgk@localhost)
 by troutmask.apl.washington.edu (8.14.9/8.14.9/Submit) id s8MGKYBL007964;
 Mon, 22 Sep 2014 09:20:34 -0700 (PDT) (envelope-from sgk)
Date: Mon, 22 Sep 2014 09:20:34 -0700
From: Steve Kargl <sgk@troutmask.apl.washington.edu>
To: Andriy Gapon <avg@FreeBSD.org>
Subject: Re: Is this a compiler bug?
Message-ID: <20140922162034.GA7918@troutmask.apl.washington.edu>
References: <20140922011946.GA4317@troutmask.apl.washington.edu>
 <670269FD-F75F-4044-8F3C-0260F58A70E2@me.com>
 <20140922014853.GA4469@troutmask.apl.washington.edu>
 <2EB3354D-0F65-4A79-A378-7F397911284A@me.com>
 <541FB79F.1070002@FreeBSD.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <541FB79F.1070002@FreeBSD.org>
User-Agent: Mutt/1.5.23 (2014-03-12)
Cc: freebsd-toolchain@FreeBSD.org, Rui Paulo <rpaulo@me.com>
X-BeenThere: freebsd-toolchain@freebsd.org
X-Mailman-Version: 2.1.18-1
Precedence: list
List-Id: Maintenance of FreeBSD's integrated toolchain
 <freebsd-toolchain.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-toolchain>, 
 <mailto:freebsd-toolchain-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-toolchain/>
List-Post: <mailto:freebsd-toolchain@freebsd.org>
List-Help: <mailto:freebsd-toolchain-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-toolchain>, 
 <mailto:freebsd-toolchain-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 22 Sep 2014 16:20:36 -0000

On Mon, Sep 22, 2014 at 08:46:07AM +0300, Andriy Gapon wrote:
> On 22/09/2014 05:20, Rui Paulo wrote:
> > On Sep 21, 2014, at 18:48, Steve Kargl <sgk@troutmask.apl.washington.edu> wrote:
> >> On Sun, Sep 21, 2014 at 06:38:48PM -0700, Rui Paulo wrote:
> >>> On Sep 21, 2014, at 18:19, Steve Kargl <sgk@troutmask.apl.washington.edu> wrote:
> >>>>
> >>>> #include <stdio.h>
> >>>> #include <stdint.h>
> >>>>
> >>>> int
> >>>> main(void)
> >>>> {
> >>>> 	uint16_t i;
> >>>> 	i = 0x3ffe+63; printf("%x\n", i);
> >>>> 	return 0;
> >>>> }
> >>>
> >>> Looks like it.  Please file a bug report with LLVM.
> >>>
> >>
> >> Unfortunately, llvm requires an account to report bugs.
> > 
> > I think I know what's happening:  "e" is being parsed as
> > scientific notation.
> 
> Interesting!  One of the cases where the whitespace matters?
> 

In a discussion on a GCC list, I was pointed to the section of
n1256.pdf where preprocessing numbers are discussed.  0x3ffe+63
is preprocessed as a single token.  When the parser finally gets
around to classifying this token, it is neither a valid integer
constant nor floating point constant.  It's just a weird feature
(idiosyncrasy?) of the C language.

-- 
Steve