From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <hjl.tools@gmail.com>
Received: from mail-pf1-x42c.google.com (mail-pf1-x42c.google.com
 [IPv6:2607:f8b0:4864:20::42c])
 by sourceware.org (Postfix) with ESMTPS id 29E873858409
 for <gcc@gcc.gnu.org>; Fri, 31 Dec 2021 20:53:29 +0000 (GMT)
DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 29E873858409
Received: by mail-pf1-x42c.google.com with SMTP id u20so24424184pfi.12
 for <gcc@gcc.gnu.org>; Fri, 31 Dec 2021 12:53:29 -0800 (PST)
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
 d=1e100.net; s=20210112;
 h=x-gm-message-state:mime-version:references:in-reply-to:from:date
 :message-id:subject:to:cc;
 bh=LKiTA4Mdf/EgnUJb9320XlWiiop3kk4DDj2s9QKW1X0=;
 b=pIlTjmnM6Szxkkqa3aCNoRVI12QvaKDCLtQC8DITSkTwZASkmgwhE79Gp45fxzz8P7
 fkzTvy63s3M2k8TyLcwy6G+NzobhvOI/cjsiWPZdrIJS/20aI0C7FjVjIygyiBJoJ00K
 OsQXUSkRZIooXNFXsIHroW0hi2XIwM2em4l9VZAj26pkmWawsYPXkCVJzag6+fH9hFgm
 Ts9mdFHsTd09WU6yHronShpe43Yy4eUrkxKH4BV2SQbt33ihqY71NYWTxJLU3VLkXJmN
 OEliuyHxy7OTkKRMJDX2y+1Z1eigaBJim2EQRRqbg956w2PYkFU+00mnv60y+wNA7HhT
 SbAw==
X-Gm-Message-State: AOAM533PN70JAOOjaYLEZU0nIm+1YGSOACI13iGAZf1xtDOlMs73L2BN
 IypJRd3vukC+z/aq4iKNQDWX2QRaeNXkYOPedcU=
X-Google-Smtp-Source: ABdhPJyO7rCHuof7Qj0hzTDC5Jz1iAtoLU00b6d2Whm/pv4llNjIZWO9ZnwKABomgXjJX68WUf+3uLpTi+p//HriBh4=
X-Received: by 2002:a05:6a00:2402:b0:4a8:4557:e96b with SMTP id
 z2-20020a056a00240200b004a84557e96bmr36738571pfh.76.1640984008209; Fri, 31
 Dec 2021 12:53:28 -0800 (PST)
MIME-Version: 1.0
References: <20211231182010.107040-1-hjl.tools@gmail.com>
 <CAFUsyfJ5wHJHkfcL84j+GLCX-Dba4qVt_RuCpu=aLy7-_YbHLA@mail.gmail.com>
 <CAMe9rOq0cW28i-_DeLfdxD3HDRTXy17ie9ZC1NxsqfRLjBz4Yw@mail.gmail.com>
 <87h7aofqtx.fsf@mid.deneb.enyo.de>
In-Reply-To: <87h7aofqtx.fsf@mid.deneb.enyo.de>
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Fri, 31 Dec 2021 12:52:52 -0800
Message-ID: <CAMe9rOoY+=HqgDWAn7QZFTeLQZjJnr4AAFmmZ+zPqt+Hdj7MwQ@mail.gmail.com>
Subject: Re: [PATCH] x86-64: Optimize memset for zeroing
To: Florian Weimer <fw@deneb.enyo.de>
Cc: "H.J. Lu via Libc-alpha" <libc-alpha@sourceware.org>,
 Noah Goldstein <goldstein.w.n@gmail.com>, 
 GCC Development <gcc@gcc.gnu.org>, Arjan van de Ven <arjan@linux.intel.com>
Content-Type: text/plain; charset="UTF-8"
X-Spam-Status: No, score=-1008.9 required=5.0 tests=BAYES_00, DKIM_SIGNED,
 DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, RCVD_IN_DNSWL_NONE,
 SPF_HELO_NONE, SPF_PASS,
 TXREP autolearn=unavailable autolearn_force=no version=3.4.4
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on
 server2.sourceware.org
X-BeenThere: gcc@gcc.gnu.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Gcc mailing list <gcc.gcc.gnu.org>
List-Unsubscribe: <https://gcc.gnu.org/mailman/options/gcc>,
 <mailto:gcc-request@gcc.gnu.org?subject=unsubscribe>
List-Archive: <https://gcc.gnu.org/pipermail/gcc/>
List-Post: <mailto:gcc@gcc.gnu.org>
List-Help: <mailto:gcc-request@gcc.gnu.org?subject=help>
List-Subscribe: <https://gcc.gnu.org/mailman/listinfo/gcc>,
 <mailto:gcc-request@gcc.gnu.org?subject=subscribe>
X-List-Received-Date: Fri, 31 Dec 2021 20:53:30 -0000

On Fri, Dec 31, 2021 at 12:43 PM Florian Weimer <fw@deneb.enyo.de> wrote:
>
> * H. J. Lu via Libc-alpha:
>
> > bzero is an alias of SSE2 memset in glibc.   Should we add __memsetzero
> > like __memcmpeq?  It should be almost free in glibc.  GCC can use
> > __memsetzero if it is available.
>
> bzero does not have the interface ambiguity that bcmp has.  So the
> only reason for not using it would be namespace cleanliness.

bzero isn't a standard C function and it isn't optimized like memset
in glibc.

-- 
H.J.