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=-5.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 59037C64E90 for ; Mon, 30 Nov 2020 14:19:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EB4D7221FD for ; Mon, 30 Nov 2020 14:19:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="xnZMQ0V1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727529AbgK3OTM (ORCPT ); Mon, 30 Nov 2020 09:19:12 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45720 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726539AbgK3OTL (ORCPT ); Mon, 30 Nov 2020 09:19:11 -0500 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4A66CC0613D3 for ; Mon, 30 Nov 2020 06:18:16 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=sJ+ka9ehbBMVNS8y8pzP5FQoENz2n/b9KCNAkBAxDhQ=; b=xnZMQ0V1YxZf479NQX/Hty0e1 RdUvqa8xWEV6UBmNosrUYJA4/H6Xb2XfD9/R7AaTCQZBVDVCpSrjN74OOctIeJcslawGoilxKGvIu r+fd5n5zixNmPKE8JHmCy4ijHZ+THoaoVAdFhIqAVJpaKh5BDl++2QC+6zZoITQa5g7SssnZI/KJK zDxvdShtAfbk8z5b66de1R7L/PyOURyMavqgnLOg0k1awvKYJH5VzW/La/meN3dUujalORgdOdxR2 LsPlpXGUAeQ7GEc/8hLh2AiE6omz7nJ7DG3u3f6TxWtOvUher2QTDzzjn17iZKdXf7WICiZkpnZ9v ToayO/mxA==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:38012) by pandora.armlinux.org.uk with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kjk0G-0006sS-IF; Mon, 30 Nov 2020 14:18:08 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1kjk0C-00054X-SR; Mon, 30 Nov 2020 14:18:04 +0000 Date: Mon, 30 Nov 2020 14:18:04 +0000 From: Russell King - ARM Linux admin To: David Laight Cc: 'Ard Biesheuvel' , Antony Yu , Nicolas Pitre , Nick Desaulniers , Linux Kernel Mailing List , clang-built-linux , Nathan Chancellor , Linux ARM Subject: Re: [RESEND,PATCH] ARM: fix __div64_32() error when compiling with clang Message-ID: <20201130141804.GV1551@shell.armlinux.org.uk> References: <20201123073634.6854-1-swpenim@gmail.com> <20201130102122.GT1551@shell.armlinux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: Russell King - ARM Linux admin Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 30, 2020 at 01:58:27PM +0000, David Laight wrote: > > And actually, the same applies on BE, but the other way around. So we > > should mark __xl as an output register as well, as __xl will assume > > the right value depending on the endianness. > > Why not use "+r" to indicate than an 'output' parameter is also > used as an input. > > Rather cleaner than specifying the same C variable as both > input and output. You have an incorrect understanding. "__n" is the input operand in r0. "__rem" is the output operand in r0/r1. No single C variable is used as both an input and an output. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!