From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vs1-xe30.google.com (mail-vs1-xe30.google.com [IPv6:2607:f8b0:4864:20::e30]) by sourceware.org (Postfix) with ESMTPS id 321F83858D1E for ; Thu, 18 Aug 2022 00:48:59 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 321F83858D1E Received: by mail-vs1-xe30.google.com with SMTP id m66so77143vsm.12 for ; Wed, 17 Aug 2022 17:48:59 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc; bh=oqP1MV6JebO/OKs3JARZ3LR8jiGntrUz2rHJKkBhPzk=; b=rwjKVNGwTPW6qCcvQMFtwXqImwknVCcewxnBr9oLWP4UQh0bytjRoT4DKPN5lcBzd8 vDqiC3muGfAj6Pr2UY1h9aDXoO95bawbmwsHxB+8JbjeR7BwnTdJ/XrUWfN7PsYg5m2q 8ufs+zUFo3jOTwrUFBnAhmEEgkEYQc4UkU233qBCqRGYcuiCqBIXgDakYglZ21sHA/OR TSkbpxYb0XYT3wCuUr4OaMe8HPw1g1s8lrA3b3m4BLS6bE+JZnlcBJk3BlDl3BkAjBRi BJK45HkwWC9MnJZdLP//VI2LYZAwPIXRdAAwO0CgD9725IRRZiYuwaEXRVjpUD3DAvWv 65jA== X-Gm-Message-State: ACgBeo1QrFtsbYWcmp5hNs42uG6WHB0reyoUrnw6jaESIJNUA78P8kUm Q7jW2MSP/upPpx/ruqHDR6yDWAXr6HSwDif5J6w= X-Google-Smtp-Source: AA6agR49VMCoL1nWb9C+ezhZcLItgNm4Mb+xIx/2O44qjpWPRkyIAQzDeLVolAziK66vzCrEyXiWYhtsMCOJKcCpXVk= X-Received: by 2002:a67:d193:0:b0:388:8152:c785 with SMTP id w19-20020a67d193000000b003888152c785mr321115vsi.65.1660783738454; Wed, 17 Aug 2022 17:48:58 -0700 (PDT) MIME-Version: 1.0 References: <70d62887-e221-786b-cf16-612be9f7c179@yahoo.co.jp> In-Reply-To: <70d62887-e221-786b-cf16-612be9f7c179@yahoo.co.jp> From: Max Filippov Date: Wed, 17 Aug 2022 17:49:10 -0700 Message-ID: Subject: Re: [PATCH] xtensa: Optimize stack pointer updates in function pro/epilogue under certain conditions To: "Takayuki 'January June' Suwa" Cc: GCC Patches Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-0.0 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, FROM_LOCAL_NOVOWEL, HK_RANDOM_ENVFROM, HK_RANDOM_FROM, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: gcc-patches@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-patches mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 18 Aug 2022 00:49:00 -0000 On Wed, Aug 17, 2022 at 12:32 PM Takayuki 'January June' Suwa wrote: > > This patch enforces the use of "addmi" machine instruction instead of > addition/subtraction with two source registers for adjusting the stack > pointer, if the adjustment fits into a signed 16-bit and is also a multiple > of 256. > > /* example */ > void test(void) { > char buffer[4096]; > __asm__(""::"m"(buffer)); > } > > ;; before > test: > movi.n a9, 1 > slli a9, a9, 12 > sub sp, sp, a9 > movi.n a9, 1 > slli a9, a9, 12 > add.n sp, sp, a9 > addi sp, sp, 0 > ret.n > > ;; after > test: > addmi sp, sp, -0x1000 > addmi sp, sp, 0x1000 > ret.n > > gcc/ChangeLog: > > * config/xtensa/xtensa.cc (xtensa_expand_prologue): > Use an "addmi" machine instruction for updating the stack pointer > rather than addition/subtraction via hard register A9, if the amount > of change satisfies the literal value conditions of that instruction > when the CALL0 ABI is used. > (xtensa_expand_epilogue): Ditto. > And also inhibit the stack pointer addition of constant zero. > --- > gcc/config/xtensa/xtensa.cc | 79 +++++++++++++++++++++++++------------ > 1 file changed, 54 insertions(+), 25 deletions(-) Regtested for target=xtensa-linux-uclibc, no new regressions. Committed to master. -- Thanks. -- Max