From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 118902 invoked by alias); 22 Sep 2017 15:59:35 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Received: (qmail 118890 invoked by uid 89); 22 Sep 2017 15:59:35 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.4 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE,RCVD_IN_SORBS_SPAM,SPF_PASS autolearn=no version=3.3.2 spammy= X-HELO: mail-qt0-f170.google.com Received: from mail-qt0-f170.google.com (HELO mail-qt0-f170.google.com) (209.85.216.170) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 22 Sep 2017 15:59:34 +0000 Received: by mail-qt0-f170.google.com with SMTP id i13so1494760qtc.11 for ; Fri, 22 Sep 2017 08:59:33 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=Pweias02ev+SUB4y5w2XKkRqTf20vNJ6WYKmJBtG6X0=; b=GDavfuBydCWO68hIJ3+zyrl/jum9vv5ys3TlWgT4XAQNCVlIxV+kiC0RnjrePr8mk1 R82UAKaJObo/CD7x96ifygVQNS3XYvF/uTOT1F6Nm9KvVGqz5QDlXXSAg5Sx4Sm3b4pp vFca4BuvV908rqEs2efjSUKVPzDmZZI255fadHwJ0btaCWRsYhf7hVIWzizrj94L7AuJ dDnzAU/NotFtlCQ6r5gfscgcUoKB70xleCZyOwrH0YWesExUtxC91/OzdE/BS8d9vkQK KB0Hc4SlKhW3IgpY0aFQJg5v85Xqc/ptmZjIyujQxvH22T5Rt8/9T4+uKJ/jn+XuZkmA Jn8Q== X-Gm-Message-State: AHPjjUh9o7b9kNWWeENwsZMvRvcqvMKf4/OftmmAoMX1noULd0BVBHiP Kl3NxoI4HohVWSNqpYQCLC/AAfBvTyqlqX6etA6goZHItNc= X-Google-Smtp-Source: AOwi7QCEvt+L0If1n2DWC7wCuM7h3yMAiMcVlPkwu9d5wroxkRFiz7Nhs1+HJCEAXqugiJsuvhZFjeA+cIHKup2puMs= X-Received: by 10.237.33.67 with SMTP id 61mr8907032qtc.148.1506095972190; Fri, 22 Sep 2017 08:59:32 -0700 (PDT) MIME-Version: 1.0 Received: by 10.140.92.205 with HTTP; Fri, 22 Sep 2017 08:59:31 -0700 (PDT) In-Reply-To: <1506095357-3334-1-git-send-email-jim.wilson@linaro.org> References: <1506095357-3334-1-git-send-email-jim.wilson@linaro.org> From: Jim Wilson Date: Fri, 22 Sep 2017 15:59:00 -0000 Message-ID: Subject: Re: [PATCH, AArch64] Disable reg offset in quad-word store for Falkor. To: "gcc-patches@gcc.gnu.org" Cc: Jim Wilson , Jim Wilson Content-Type: text/plain; charset="UTF-8" X-SW-Source: 2017-09/txt/msg01551.txt.bz2 On Fri, Sep 22, 2017 at 8:49 AM, Jim Wilson wrote: > On Falkor, because of an idiosyncracy of how the pipelines are designed, a > quad-word store using a reg+reg addressing mode is almost twice as slow as an > add followed by a quad-word store with a single reg addressing mode. So we > get better performance if we disallow addressing modes using register offsets > with quad-word stores. This was tested with a bootstrap and make check of course. Also, gcc.c-torture/compile/20021212-1.c compiled with -O3 -mcpu=falkor makes a nice testcase to demonstrate that the patch works. OK? Jim