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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 D4438C33C9E for ; Sat, 11 Jan 2020 11:36:30 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3BD2B20678 for ; Sat, 11 Jan 2020 11:36:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3BD2B20678 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 47vyVM5HzWzDqW3 for ; Sat, 11 Jan 2020 22:36:27 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=permerror (SPF Permanent Error: Unknown mechanism found: ip:192.40.192.88/32) smtp.mailfrom=kernel.crashing.org (client-ip=63.228.1.57; helo=gate.crashing.org; envelope-from=segher@kernel.crashing.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 47vyRf3Hg7zDqD7 for ; Sat, 11 Jan 2020 22:34:06 +1100 (AEDT) Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 00BBXTQb023225; Sat, 11 Jan 2020 05:33:29 -0600 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 00BBXSxW023224; Sat, 11 Jan 2020 05:33:28 -0600 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Sat, 11 Jan 2020 05:33:28 -0600 From: Segher Boessenkool To: Christophe Leroy Subject: Re: Surprising code generated for vdso_read_begin() Message-ID: <20200111113328.GX3191@gate.crashing.org> References: <20200109200733.GS3191@gate.crashing.org> <77a8bf25-6615-6c0a-56d4-eae7aa8a8f09@c-s.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <77a8bf25-6615-6c0a-56d4-eae7aa8a8f09@c-s.fr> User-Agent: Mutt/1.4.2.3i X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: arnd@arndb.de, x86@kernel.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, Paul Mackerras , luto@kernel.org, tglx@linutronix.de, vincenzo.frascino@arm.com, linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Fri, Jan 10, 2020 at 07:45:44AM +0100, Christophe Leroy wrote: > Le 09/01/2020 à 21:07, Segher Boessenkool a écrit : > >It looks like the compiler did loop peeling. What GCC version is this? > >Please try current trunk (to become GCC 10), or at least GCC 9? > > It is with GCC 5.5 > > https://mirrors.edge.kernel.org/pub/tools/crosstool/ doesn't have more > recent than 8.1 Arnd, can you update the tools? We are at 8.3 and 9.2 now :-) Or is this hard and/or painful to do? > With 8.1, the problem doesn't show up. Good to hear that. Hrm, I wonder when it was fixed... Segher