From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-help-return-54054-listarch-gcc-help=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 26900 invoked by alias); 9 Oct 2013 10:16:32 -0000
Mailing-List: contact gcc-help-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-help.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-help/>
List-Post: <mailto:gcc-help@gcc.gnu.org>
List-Help: <mailto:gcc-help-help@gcc.gnu.org>
Sender: gcc-help-owner@gcc.gnu.org
Received: (qmail 26887 invoked by uid 89); 9 Oct 2013 10:16:31 -0000
Authentication-Results: sourceware.org; auth=none
X-Spam-SWARE-Status: No, score=-2.8 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2
X-HELO: mail-lb0-f177.google.com
Received: from mail-lb0-f177.google.com (HELO mail-lb0-f177.google.com) (209.85.217.177) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-SHA encrypted) ESMTPS; Wed, 09 Oct 2013 10:16:30 +0000
Received: by mail-lb0-f177.google.com with SMTP id w7so562539lbi.8        for <gcc-help@gcc.gnu.org>; Wed, 09 Oct 2013 03:16:27 -0700 (PDT)
MIME-Version: 1.0
X-Received: by 10.152.120.73 with SMTP id la9mr5657872lab.3.1381313786964; Wed, 09 Oct 2013 03:16:26 -0700 (PDT)
Received: by 10.112.101.7 with HTTP; Wed, 9 Oct 2013 03:16:26 -0700 (PDT)
In-Reply-To: <CAKhyrx-A7pLK1OEiNDuMNJT75tErLBk0MHNnPxuxo=RyM7p=4g@mail.gmail.com>
References: <CAKhyrx_1m0K868TVXg8kwo+EhbB+VFV0RkPqDHJ+FA8BV4w4Gw@mail.gmail.com>	<CAH6eHdTouwYdhn4H6OEZJy2CEirb9oxYejg5q_CtPQmwVo3YmQ@mail.gmail.com>	<CAKhyrx-A7pLK1OEiNDuMNJT75tErLBk0MHNnPxuxo=RyM7p=4g@mail.gmail.com>
Date: Wed, 09 Oct 2013 10:16:00 -0000
Message-ID: <CAH6eHdSOX7=aBGUhGY5nx0V+sRCLPPy+zHL4OVWREQJRCdRGnw@mail.gmail.com>
Subject: Re: Crazy compiler optimization
From: Jonathan Wakely <jwakely.gcc@gmail.com>
To: vijay nag <vijunag@gmail.com>
Cc: "gcc-help@gcc.gnu.org" <gcc-help@gcc.gnu.org>
Content-Type: text/plain; charset=ISO-8859-1
X-IsSubscribed: yes
X-SW-Source: 2013-10/txt/msg00012.txt.bz2

On 9 October 2013 11:02, vijay nag wrote:
> Alright that is perfectly valid behaviour. Why does compiler consider
> it to be a unsigned type at optimization level zero ?

It doesn't.

> i.e. I see a
> wrap around after
> -128 to 128 ?

Because undefined behaviour.