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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A1BB9C001DF for ; Wed, 2 Aug 2023 06:00:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232164AbjHBGA0 (ORCPT ); Wed, 2 Aug 2023 02:00:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53534 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232118AbjHBGAU (ORCPT ); Wed, 2 Aug 2023 02:00:20 -0400 Received: from wout5-smtp.messagingengine.com (wout5-smtp.messagingengine.com [64.147.123.21]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BD24C213D; Tue, 1 Aug 2023 23:00:13 -0700 (PDT) Received: from compute6.internal (compute6.nyi.internal [10.202.2.47]) by mailout.west.internal (Postfix) with ESMTP id E63BD320094E; Wed, 2 Aug 2023 02:00:10 -0400 (EDT) Received: from imap51 ([10.202.2.101]) by compute6.internal (MEProxy); Wed, 02 Aug 2023 02:00:12 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=arndb.de; h=cc :cc:content-type:content-type:date:date:from:from:in-reply-to :in-reply-to:message-id:mime-version:references:reply-to:sender :subject:subject:to:to; s=fm2; t=1690956010; x=1691042410; bh=Yt vb0mJTCqFvSWUzjrpJ3J+FljcDta2FuHCw3g9+xyM=; b=X8GskQHKcF/CLu6sH9 eHdMyaeNGKePN3uazuZn7+yG1MgasXQeSW+4D5a9qh01PZJ7ruxAhWLUmqLv/5A1 W6H07qlbCkDckdcSq23RL5reCF4qGn2CJ7AFFzvrvuiIyF6avFGWDuPiIDTDDza7 sITrpD0bLEVEOugi610GvCf2CpcRN/uAN7rFDfopQ9Kls2M+mvohHTIgclscWePT IzeLsuUrotGQT+H+7RNajuQNxx1XCoa1DvJJ5Hga0P3V/DrFgmlN48jWyzxywzvR EIsEeQt1j8VMOaYXXdnLEFTpd/PIDbv3gVRDO2Rf4qW2CutL5wCa7f3aFyUesjBm qnXA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:content-type:date:date :feedback-id:feedback-id:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:sender:subject :subject:to:to:x-me-proxy:x-me-proxy:x-me-sender:x-me-sender :x-sasl-enc; s=fm3; t=1690956010; x=1691042410; bh=Ytvb0mJTCqFvS WUzjrpJ3J+FljcDta2FuHCw3g9+xyM=; b=rVZI7NEq96ProyK7mRRMmZ9uNP1XY U60ejYdcwBAhAR8FRm0b43P47NNM4476RHXJVqz/nect8HFS32ww2FrZLZfDJNFj nTnKfBQ8SOHjto76Bp9hInu8Z2aQgIa95Tj0/F+hnsevQld0WJob9UOapGSFOrr5 N+cc0kc4CXtrZ9sb+emUOVvGisqm5TaiFNe0yyVC4BFqIe069x7BSdzhm3i9GTlL AxvGwPLPUCK3283/Shk2fhcVU6K8QFI2TOkxy+6PQD4C/MzdLPr25hYGQV6ncCu9 K1tQdzUC8qIQLrxnIQQcYoqNk6IjHludpZUC7nMTg3HpQ+ejVpLz7Nv/A== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedviedrjeejgddutddtucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhepofgfggfkjghffffhvfevufgtsehttdertderredtnecuhfhrohhmpedftehr nhguuceuvghrghhmrghnnhdfuceorghrnhgusegrrhhnuggsrdguvgeqnecuggftrfgrth htvghrnhepffehueegteeihfegtefhjefgtdeugfegjeelheejueethfefgeeghfektdek teffnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomheprg hrnhgusegrrhhnuggsrdguvg X-ME-Proxy: Feedback-ID: i56a14606:Fastmail Received: by mailuser.nyi.internal (Postfix, from userid 501) id D5750B60089; Wed, 2 Aug 2023 02:00:09 -0400 (EDT) X-Mailer: MessagingEngine.com Webmail Interface User-Agent: Cyrus-JMAP/3.9.0-alpha0-592-ga9d4a09b4b-fm-defalarms-20230725.001-ga9d4a09b Mime-Version: 1.0 Message-Id: <847747a8-b773-4b7b-8c14-b8ef4ba7c022@app.fastmail.com> In-Reply-To: References: <20230801-bitwise-v1-1-799bec468dc4@google.com> Date: Wed, 02 Aug 2023 07:59:48 +0200 From: "Arnd Bergmann" To: "Linus Torvalds" , "Nick Desaulniers" Cc: "Nathan Chancellor" , "Tom Rix" , Linux-Arch , linux-kernel@vger.kernel.org, llvm@lists.linux.dev, "Heiko Carstens" , "Vasily Gorbik" , "Alexander Gordeev" , "Christian Borntraeger" , "Sven Schnelle" , linux-s390@vger.kernel.org, "Thomas Bogendoerfer" Subject: Re: [PATCH] word-at-a-time: use the same return type for has_zero regardless of endianness Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 2, 2023, at 03:07, Linus Torvalds wrote: > On Tue, 1 Aug 2023 at 15:22, wrote: > Who ends up being affected by this? Powerpc does its own > word-at-a-time thing because the big-endian case is nasty and you can > do better with special instructions that they have. powerpc needs the same patch though. > Who else is even BE any more? Some old 32-bit arm setup? > > I think the patch is fine, but I guess I'd like to know that people > who are affected actually don't see any code generation changes (or > possibly see improvements from not turning it into a bool until later) s390 is the main one here, maintainers added to Cc. Atheros and Realtek MIPS are older but still shipping in low-end network equipment, and there are still users on old embedded big-endian mips (broadcom, cavium, intel/lantiq and arm (intel ixp4xx) hardware. All modern Arm hardware (v6/v7/v8/v9) can do both big-endian and little-endian, but actual user numbers for big-endian are close to zero -- I have not heard from anyone actually using it in years. And then there was a lot of the old-school workstation/server hardware (m68k, mips, parisc and sparc, not alpha/ia64) that is mostly big-endian and still maintained to some degree. Arnd