From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6CE5EC169C4 for ; Fri, 8 Feb 2019 07:34:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3D5FF21924 for ; Fri, 8 Feb 2019 07:34:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="rdDY3gew" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727191AbfBHHeI (ORCPT ); Fri, 8 Feb 2019 02:34:08 -0500 Received: from mail-wr1-f43.google.com ([209.85.221.43]:40802 "EHLO mail-wr1-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726063AbfBHHeI (ORCPT ); Fri, 8 Feb 2019 02:34:08 -0500 Received: by mail-wr1-f43.google.com with SMTP id q1so2443785wrp.7 for ; Thu, 07 Feb 2019 23:34:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:mime-version:content-disposition :user-agent; bh=inJqTiEgrDhETE3bawzlt9w7vAaWsM+B/ix4JgWmlzQ=; b=rdDY3gewVCY3boh17ik2SLDntkFFb4mCeaCS2w/ekFadHSdT0U0dBHDdyHMS/+6WMv 2/BJu9ajF7cMPRJiDPmjWq7tBwhIOdVB0QeVsGZzVnivdmZndB2RFHJRjMkpuWkvuPpJ wlI4JshP1Ae3Pmtnf8eSTDcZ2myjkESMfYCg6GU8a+xoIn9bM9zC02tpMGr85pEgh1j7 VqBAQsvWqnxc69+ScarufyBVuZOdNaZz654nOE8W+NzhZJ0p2UhxZe0gbb79lesTl1yF thQcYZqxnvSsAVhoWvxUdi8qSVvo3SR6qBqSB7+9loA6I+kwfDkTe8szcsWySvAgP2ht PPWg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition:user-agent; bh=inJqTiEgrDhETE3bawzlt9w7vAaWsM+B/ix4JgWmlzQ=; b=C3SdtBC6jlpZMDSdKa0Qxp299kpeUhyM/vWlk0yArsXivjpjvtct6iH1I048Bgt/8c GkKyZPMuGS+J1Y/e4Cp1pUMX4O1/QYWqaR7VRwBlVa3koPdqAfuemkuopq/g5AWu3J/P 2pXemBJANX/f20VeoJeCpVmkRMOsABwKGnEL7pNw8X5CPKxLvbMLehei9X4Q9pWLzCqy P9SFSxIx3MmI0Y7oASqqUuiyD7Q5ycP0M8ikB0IkcAHeA1/Ou+7FycWpKrZhv01P6Uzu eQ8FZWnvFPVdHI3drk4X4P8EPHsdCuMS+aH6wRJlT9J0mmGeqrqqCwOvR0JU/Q0tNDjL XKTg== X-Gm-Message-State: AHQUAuY8VT7rRujVye2RPePcKCNLbwSZmSyW6A/WsloDTgMwuv2v/UXD PPio3TRZm3ztCqGtvVAKFGgivJk= X-Google-Smtp-Source: AHgI3IacUK1/HahP7D5gaAUBhhOmmxSB026i8vXdaAly6FdddQTtylJkJ9YedQcgVL5YpwvX2FUqug== X-Received: by 2002:a5d:5750:: with SMTP id q16mr15138329wrw.12.1549611246253; Thu, 07 Feb 2019 23:34:06 -0800 (PST) Received: from avx2 ([46.53.243.121]) by smtp.gmail.com with ESMTPSA id d17sm679588wrw.68.2019.02.07.23.34.04 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 07 Feb 2019 23:34:05 -0800 (PST) Date: Fri, 8 Feb 2019 10:34:03 +0300 From: Alexey Dobriyan To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org Subject: [PATCH] lib/string.c: make strncmp() smaller Message-ID: <20190208073403.GA19734@avx2> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Space savings on x86_64: add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-29 (-29) Function old new delta strncmp 67 38 -29 Space savings on arm: add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-60 (-60) Function old new delta strncmp 116 56 -60 Signed-off-by: Alexey Dobriyan --- lib/string.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) --- a/lib/string.c +++ b/lib/string.c @@ -344,16 +344,14 @@ EXPORT_SYMBOL(strcmp); */ int strncmp(const char *cs, const char *ct, size_t count) { - unsigned char c1, c2; + while (count--) { + unsigned int c1 = *(unsigned char *)cs++; + unsigned int c2 = *(unsigned char *)ct++; - while (count) { - c1 = *cs++; - c2 = *ct++; if (c1 != c2) - return c1 < c2 ? -1 : 1; + return c1 - c2; if (!c1) break; - count--; } return 0; }