From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-patches-return-454673-listarch-gcc-patches=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 81112 invoked by alias); 29 May 2017 12:21:28 -0000
Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-patches.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-patches/>
List-Post: <mailto:gcc-patches@gcc.gnu.org>
List-Help: <mailto:gcc-patches-help@gcc.gnu.org>
Sender: gcc-patches-owner@gcc.gnu.org
Received: (qmail 81100 invoked by uid 89); 29 May 2017 12:21:27 -0000
Authentication-Results: sourceware.org; auth=none
X-Virus-Found: No
X-Spam-SWARE-Status: No, score=-2.0 required=5.0 tests=AWL,BAYES_00,RP_MATCHES_RCVD autolearn=ham version=3.3.2 spammy=22pm, 22PM, H*r:8.14.1
X-HELO: gate.crashing.org
Received: from gate.crashing.org (HELO gate.crashing.org) (63.228.1.57) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Mon, 29 May 2017 12:21:27 +0000
Received: from gate.crashing.org (localhost.localdomain [127.0.0.1])	by gate.crashing.org (8.14.1/8.13.8) with ESMTP id v4TCLMBO018707;	Mon, 29 May 2017 07:21:22 -0500
Received: (from segher@localhost)	by gate.crashing.org (8.14.1/8.14.1/Submit) id v4TCLLJk018704;	Mon, 29 May 2017 07:21:21 -0500
Date: Mon, 29 May 2017 12:23:00 -0000
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Richard Biener <richard.guenther@gmail.com>
Cc: will_schmidt@vnet.ibm.com, GCC Patches <gcc-patches@gcc.gnu.org>,        David Edelsohn <dje.gcc@gmail.com>,        Bill Schmidt <wschmidt@linux.vnet.ibm.com>
Subject: Re: [PATCH, rs6000] Fold vector absolutes in GIMPLE
Message-ID: <20170529122120.GL19687@gate.crashing.org>
References: <1495819159.15163.170.camel@brimstone.rchland.ibm.com> <CAFiYyc3QrvoAKgfmu0nL233C1ggWH=NTmCiBO8LEB7MC6z=fEQ@mail.gmail.com> <20170529102444.GI19687@gate.crashing.org> <A41966D2-362E-4278-9989-0A2474541696@gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <A41966D2-362E-4278-9989-0A2474541696@gmail.com>
User-Agent: Mutt/1.4.2.3i
X-IsSubscribed: yes
X-SW-Source: 2017-05/txt/msg02183.txt.bz2

On Mon, May 29, 2017 at 01:35:22PM +0200, Richard Biener wrote:
> >> What's the documented behavior for vec_abs with respect to an
> >argument
> >> of value INT_MIN?
> >
> >The documentation says:
> >
> >	"For integer vectors, the arithmetic is modular."
> 
> This means that folding as ABS_EXPR is not safe for !TYPE_OVERFLOW_WRAPS
> Integral vector types.

Is it still fine if TYPE_OVERFLOW_UNDEFINED?  So essentially always
except with -ftrapv?


Segher