From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-patches-return-405504-listarch-gcc-patches=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 89199 invoked by alias); 19 Aug 2015 01:54:57 -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 89080 invoked by uid 89); 19 Aug 2015 01:54:57 -0000
Authentication-Results: sourceware.org; auth=none
X-Virus-Found: No
X-Spam-SWARE-Status: No, score=-2.2 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2
X-HELO: mail-ob0-f174.google.com
Received: from mail-ob0-f174.google.com (HELO mail-ob0-f174.google.com) (209.85.214.174) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-GCM-SHA256 encrypted) ESMTPS; Wed, 19 Aug 2015 01:54:55 +0000
Received: by obbhe7 with SMTP id he7so156983170obb.0        for <gcc-patches@gcc.gnu.org>; Tue, 18 Aug 2015 18:54:53 -0700 (PDT)
MIME-Version: 1.0
X-Received: by 10.182.250.195 with SMTP id ze3mr8351799obc.74.1439949293328; Tue, 18 Aug 2015 18:54:53 -0700 (PDT)
Received: by 10.76.94.211 with HTTP; Tue, 18 Aug 2015 18:54:53 -0700 (PDT)
In-Reply-To: <55D37601.6060200@redhat.com>
References: <000401d0c918$d7a2e780$86e8b680$@arm.com>	<CAFiYyc0PS9riH1LKKtQjuQsPwfw66kHpbCfZ6d_fp2ykhAXjKA@mail.gmail.com>	<CAHFci29KkT64t-aAkhCPdFippjn1Rgg9E+Xp_ETFU0C8ihB90A@mail.gmail.com>	<55D37601.6060200@redhat.com>
Date: Wed, 19 Aug 2015 02:45:00 -0000
Message-ID: <CAHFci2_7gSd5Pv3VpL11baeBPOJs7HRGt6ntviOOUk-y+nF+iQ@mail.gmail.com>
Subject: Re: [PATCH GCC]Improve bound information in loop niter analysis
From: "Bin.Cheng" <amker.cheng@gmail.com>
To: Jeff Law <law@redhat.com>
Cc: Richard Biener <richard.guenther@gmail.com>, Bin Cheng <bin.cheng@arm.com>, 	GCC Patches <gcc-patches@gcc.gnu.org>
Content-Type: text/plain; charset=UTF-8
X-IsSubscribed: yes
X-SW-Source: 2015-08/txt/msg01041.txt.bz2

On Wed, Aug 19, 2015 at 2:14 AM, Jeff Law <law@redhat.com> wrote:
> On 08/17/2015 04:01 AM, Bin.Cheng wrote:
>>>
>>>
>>> +      c0 = fold_convert (type, c0);
>>> +      c1 = fold_convert (type, c1);
>>> +
>>> +      if (operand_equal_p (var, c0, 0))
>>>
>>> I believe if c0 is not already of type type operand-equal_p will never
>>> succeed.
>>
>> It's quite specific case targeting comparison between var and it's
>> range bounds.  Given c0 is in form of "var + offc0", then the
>> comparison "var + offc0 != range bounds" doesn't have any useful
>> information.  Maybe useless type conversion can be handled here
>> though, it might be even corner case.
>
> My comment about useless type conversions was more about a deficiency in
> operand_equal_p's implementation.  It wasn't something I felt needed to be
> addressed in your patch.
>
> I think using operand_equal_p is fine here.
Hi Jeff,
I misunderstood the point.  Thanks for explanation.  Given the
approval, new version patch is applied.

Thanks,
bin
>
>
> Jeff