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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=ham 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 F14B2C28CC0 for ; Thu, 30 May 2019 17:58:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CDF8525EE7 for ; Thu, 30 May 2019 17:58:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=synopsys.com header.i=@synopsys.com header.b="T/4O9utu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726809AbfE3R6U (ORCPT ); Thu, 30 May 2019 13:58:20 -0400 Received: from smtprelay-out1.synopsys.com ([198.182.61.142]:55704 "EHLO smtprelay-out1.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726461AbfE3R6U (ORCPT ); Thu, 30 May 2019 13:58:20 -0400 Received: from mailhost.synopsys.com (dc2-mailhost2.synopsys.com [10.12.135.162]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by smtprelay-out1.synopsys.com (Postfix) with ESMTPS id 8F0FEC00DB; Thu, 30 May 2019 17:58:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=synopsys.com; s=mail; t=1559239082; bh=5GP4w1Bpe5t07VP8WSgVlPbfP1asIntV9WMlEi3rPoY=; h=Subject:To:CC:References:From:Date:In-Reply-To:From; b=T/4O9utu9pPN7m60uY41ltPxBEK8Lws7ZwOUvxoq8FxRfdz+YjDpwMiIafaYtXDWp JuHTMvc+8Bz7hRXgFgGx/fGpiZeyp46VOFiTn0VW8MVCZAXCGwwmV/xj60Mg4HO5Qh GaDUN+y/i1XQxVm3QG7ys4NhGvOO5GsDVMZEI36TluK8wTqYRqUB6qFG9QXO0R93zq 05RquOVtgBMK14YsNRBzKBeGrdaMkyeEcjwNsrbVXAlfD/h/lvurghUpLSX47uVtvZ a67BDzKbEiFpXckZKEkqRZ1Ns0QHztYD2uk3EApADovHRJq+49aw1hyTVvf2QX9DAc hhmrFwGtNZYWg== Received: from US01WEHTC2.internal.synopsys.com (us01wehtc2.internal.synopsys.com [10.12.239.237]) (using TLSv1.2 with cipher AES128-SHA256 (128/128 bits)) (No client certificate requested) by mailhost.synopsys.com (Postfix) with ESMTPS id 90C13A0093; Thu, 30 May 2019 17:58:19 +0000 (UTC) Received: from IN01WEHTCB.internal.synopsys.com (10.144.199.106) by US01WEHTC2.internal.synopsys.com (10.12.239.237) with Microsoft SMTP Server (TLS) id 14.3.408.0; Thu, 30 May 2019 10:58:19 -0700 Received: from IN01WEHTCA.internal.synopsys.com (10.144.199.103) by IN01WEHTCB.internal.synopsys.com (10.144.199.105) with Microsoft SMTP Server (TLS) id 14.3.408.0; Thu, 30 May 2019 23:28:16 +0530 Received: from [10.10.161.35] (10.10.161.35) by IN01WEHTCA.internal.synopsys.com (10.144.199.243) with Microsoft SMTP Server (TLS) id 14.3.408.0; Thu, 30 May 2019 23:28:28 +0530 Subject: extraneous generated EXTB (was Re: [PATCH 4/9] ARC: mm: do_page_fault refactor #3: tidyup vma access permission code) To: Claudiu Zissulescu CC: Eugeniy Paltsev , "paltsev@snyopsys.com" , "linux-kernel@vger.kernel.org" , Alexey Brodkin , "linux-snps-arc@lists.infradead.org" Newsgroups: gmane.linux.kernel,gmane.linux.kernel.arc References: <1557880176-24964-1-git-send-email-vgupta@synopsys.com> <1557880176-24964-5-git-send-email-vgupta@synopsys.com> <1558027448.2682.11.camel@synopsys.com> <1558131743.2682.33.camel@synopsys.com> From: Vineet Gupta Openpgp: preference=signencrypt Autocrypt: addr=vgupta@synopsys.com; keydata= mQINBFEffBMBEADIXSn0fEQcM8GPYFZyvBrY8456hGplRnLLFimPi/BBGFA24IR+B/Vh/EFk B5LAyKuPEEbR3WSVB1x7TovwEErPWKmhHFbyugdCKDv7qWVj7pOB+vqycTG3i16eixB69row lDkZ2RQyy1i/wOtHt8Kr69V9aMOIVIlBNjx5vNOjxfOLux3C0SRl1veA8sdkoSACY3McOqJ8 zR8q1mZDRHCfz+aNxgmVIVFN2JY29zBNOeCzNL1b6ndjU73whH/1hd9YMx2Sp149T8MBpkuQ cFYUPYm8Mn0dQ5PHAide+D3iKCHMupX0ux1Y6g7Ym9jhVtxq3OdUI5I5vsED7NgV9c8++baM 7j7ext5v0l8UeulHfj4LglTaJIvwbUrCGgtyS9haKlUHbmey/af1j0sTrGxZs1ky1cTX7yeF nSYs12GRiVZkh/Pf3nRLkjV+kH++ZtR1GZLqwamiYZhAHjo1Vzyl50JT9EuX07/XTyq/Bx6E dcJWr79ZphJ+mR2HrMdvZo3VSpXEgjROpYlD4GKUApFxW6RrZkvMzuR2bqi48FThXKhFXJBd JiTfiO8tpXaHg/yh/V9vNQqdu7KmZIuZ0EdeZHoXe+8lxoNyQPcPSj7LcmE6gONJR8ZqAzyk F5voeRIy005ZmJJ3VOH3Gw6Gz49LVy7Kz72yo1IPHZJNpSV5xwARAQABtCpWaW5lZXQgR3Vw dGEgKGFsaWFzKSA8dmd1cHRhQHN5bm9wc3lzLmNvbT6JAj4EEwECACgCGwMGCwkIBwMCBhUI AgkKCwQWAgMBAh4BAheABQJbBYpwBQkLx0HcAAoJEGnX8d3iisJeChAQAMR2UVbJyydOv3aV jmqP47gVFq4Qml1weP5z6czl1I8n37bIhdW0/lV2Zll+yU1YGpMgdDTHiDqnGWi4pJeu4+c5 xsI/VqkH6WWXpfruhDsbJ3IJQ46//jb79ogjm6VVeGlOOYxx/G/RUUXZ12+CMPQo7Bv+Jb+t NJnYXYMND2Dlr2TiRahFeeQo8uFbeEdJGDsSIbkOV0jzrYUAPeBwdN8N0eOB19KUgPqPAC4W HCg2LJ/o6/BImN7bhEFDFu7gTT0nqFVZNXlOw4UcGGpM3dq/qu8ZgRE0turY9SsjKsJYKvg4 djAaOh7H9NJK72JOjUhXY/sMBwW5vnNwFyXCB5t4ZcNxStoxrMtyf35synJVinFy6wCzH3eJ XYNfFsv4gjF3l9VYmGEJeI8JG/ljYQVjsQxcrU1lf8lfARuNkleUL8Y3rtxn6eZVtAlJE8q2 hBgu/RUj79BKnWEPFmxfKsaj8of+5wubTkP0I5tXh0akKZlVwQ3lbDdHxznejcVCwyjXBSny d0+qKIXX1eMh0/5sDYM06/B34rQyq9HZVVPRHdvsfwCU0s3G+5Fai02mK68okr8TECOzqZtG cuQmkAeegdY70Bpzfbwxo45WWQq8dSRURA7KDeY5LutMphQPIP2syqgIaiEatHgwetyVCOt6 tf3ClCidHNaGky9KcNSQ Message-ID: <7923928f-1f4e-3fa8-3d38-40fcb2074b4a@synopsys.com> Date: Thu, 30 May 2019 10:58:08 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <1558131743.2682.33.camel@synopsys.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.10.161.35] Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/17/19 3:23 PM, Eugeniy Paltsev wrote: > Hmmm, > > so load the bool variable from memory is converted to such asm code: > > ----------------->8------------------- > ldb r2,[some_bool_address] > extb_s r2,r2 > ----------------->8------------------- > > Could you please describe that the magic is going on there? > > This extb_s instruction looks completely useless here, according on the LDB description from PRM: > ----------------->8------------------- > LD LDH LDW LDB LDD: > The size of the requested data is specified by the data size field <.zz> and by default, data is zero > extended from the most-significant bit of the data to the most-significant bit of the destination > register. > ----------------->8------------------- > > Am I missing something? @Claudiu is that a target specific optimization/tuning in ARC backend ? > > On Thu, 2019-05-16 at 17:37 +0000, Vineet Gupta wrote: >> On 5/16/19 10:24 AM, Eugeniy Paltsev wrote: >>>> + unsigned int write = 0, exec = 0, mask; >>> >>> Probably it's better to use 'bool' type for 'write' and 'exec' as we really use them as a boolean variables. >> >> Right those are semantics, but the generated code for "bool" is not ideal - given >> it is inherently a "char" it is promoted first to an int with an additional EXTB >> which I really dislike. >> Guess it is more of a style thing. >> >> -Vineet