From patchwork Mon Aug 7 19:12:04 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luc Van Oostenryck X-Patchwork-Id: 9886051 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id C110A602CC for ; Mon, 7 Aug 2017 19:12:22 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7BFD5286BF for ; Mon, 7 Aug 2017 19:12:22 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 71048286C2; Mon, 7 Aug 2017 19:12:22 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.3 required=2.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, RCVD_IN_SORBS_SPAM, T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 16DA4286B6 for ; Mon, 7 Aug 2017 19:12:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751508AbdHGTMV (ORCPT ); Mon, 7 Aug 2017 15:12:21 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:38359 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751927AbdHGTMT (ORCPT ); Mon, 7 Aug 2017 15:12:19 -0400 Received: by mail-wm0-f66.google.com with SMTP id y206so2036310wmd.5 for ; Mon, 07 Aug 2017 12:12:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=vsR0wYWpV5YyUyXMctuo+kLzRL2BV1DJr/ynlrnnAWA=; b=pDl7bMmgHjEtxiauGms8UotWkB6VCvjrxof/AMeKG6bzKlprB9S+7ADiNUYENbksAQ dBZaPYEpyxXpIBvROHD4PVopXv0UU6oqRr2TCJfCTOLImBlbw7YaxX9P0jFRYMqIF7wP g9Q/YAmcGiJ5H6gridu456Y6RFzXxSm4rjPRt6mEgqp9dM/A/nd6BCo1f+AltpZsuMzZ qOOOpAL/jhFpOf7pySNvYJl3WhqN1pq1NfEVFiS9ToBQoTuLfEZyiqlyU3bUJyac46Lv rMEnTu9uJr4iYEHXKncqYzrSoa2ChF7W2bG2RoyiNU7kH09e3ZDpe+rfThHzdPogF4Ia QUag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=vsR0wYWpV5YyUyXMctuo+kLzRL2BV1DJr/ynlrnnAWA=; b=kMMKln8J8zHkJEb39hNTE2DBrESUjSVMwKk4QdTUvnuyBncIRemUO50Z2iva6pCtlC tc2PWbbszbD8MrhrvpHmSPlnrwEtqiQG4L5aaqBcC4ZaORbik6aQf3UZ+HFl5cOLdp1H aaypXJSK8p85fJVkluwapYEmEI3ajC0XiLsCh87CwSO18oDMwD2jgxZas4FT7TZQCIOz lfibOtRC099pflFu0NXP1Zd6IeSJVRj6M7G49IC6vnM5yl2DM2gJSfzP1JtCCkAeWhq+ mFaI7xbCsRC+2IOyPd43MeXbbYXvPg+jgnTxdhdgoGoZNnMcbFZq3ljQhc5hswjgxrhp 9dFA== X-Gm-Message-State: AHYfb5gXI8dElUrz6OR0WRgwGXI0BPlZJf9lZdnCfIU33T2ir8o0GbLr qrZF36LL/78mYw== X-Received: by 10.80.164.75 with SMTP id v11mr1966806edb.103.1502133137984; Mon, 07 Aug 2017 12:12:17 -0700 (PDT) Received: from localhost.localdomain ([2a02:a03f:4076:600:29ff:6bdc:a0fa:4163]) by smtp.gmail.com with ESMTPSA id g52sm7742064edg.34.2017.08.07.12.12.17 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 07 Aug 2017 12:12:17 -0700 (PDT) From: Luc Van Oostenryck To: Dibyendu Majumdar Cc: linux-sparse@vger.kernel.org, Luc Van Oostenryck Subject: [PATCH v2 7/8] transform (A << S) >> S into A & (-1 >> S) Date: Mon, 7 Aug 2017 21:12:04 +0200 Message-Id: <20170807191205.86590-8-luc.vanoostenryck@gmail.com> X-Mailer: git-send-email 2.13.2 In-Reply-To: <20170807191205.86590-1-luc.vanoostenryck@gmail.com> References: <20170807191205.86590-1-luc.vanoostenryck@gmail.com> Sender: linux-sparse-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sparse@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This is especially usefull when simplifying code accessing bitfields. Signed-off-by: Luc Van Oostenryck --- simplify.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/simplify.c b/simplify.c index f1a898700..cdc244c17 100644 --- a/simplify.c +++ b/simplify.c @@ -416,6 +416,7 @@ static int simplify_lsr(struct instruction *insn, pseudo_t pseudo, long long val { struct instruction *def; unsigned long long mask; + pseudo_t old; if (!value) return replace_with_pseudo(insn, pseudo); @@ -434,6 +435,20 @@ static int simplify_lsr(struct instruction *insn, pseudo_t pseudo, long long val insn->opcode = OP_AND; insn->src2 = value_pseudo(mask >> value); return REPEAT_CSE; + case OP_SHL: + // replace (A << S) >> S + // by A & (-1 >> S) + def = insn->src1->def; + if (!constant(def->src2)) + break; + if (def->src2->value != value) + break; + insn->opcode = OP_AND; + insn->src2 = value_pseudo(-1ULL >> value); + old = insn->src1; + use_pseudo(insn, def->src1, &insn->src1); + remove_usage(old, &insn->src1); + return REPEAT_CSE; } return 0; }