From patchwork Sat May 23 20:17:12 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Volker_R=C3=BCmelin?= X-Patchwork-Id: 1296774 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=t-online.de Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 49TvmH3zqlz9sRW for ; Sun, 24 May 2020 06:17:35 +1000 (AEST) Received: from localhost ([::1]:51528 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jcaaL-0004Z8-8g for incoming@patchwork.ozlabs.org; Sat, 23 May 2020 16:17:33 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59204) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jcaa5-0004Yy-FV for qemu-devel@nongnu.org; Sat, 23 May 2020 16:17:17 -0400 Received: from mailout05.t-online.de ([194.25.134.82]:56092) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jcaa4-0002Cz-Gk for qemu-devel@nongnu.org; Sat, 23 May 2020 16:17:17 -0400 Received: from fwd24.aul.t-online.de (fwd24.aul.t-online.de [172.20.26.129]) by mailout05.t-online.de (Postfix) with SMTP id 60D564207AAA; Sat, 23 May 2020 22:17:13 +0200 (CEST) Received: from linpower.localnet (ESXGesZ-8huk1nGyLyIUmycUY9WnlJQ2t5J-4u5oRwPXne6C1HZOCXTCHcKsanbgwq@[79.208.25.125]) by fwd24.t-online.de with (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384 encrypted) esmtp id 1jcaa0-0EXOJk0; Sat, 23 May 2020 22:17:12 +0200 Received: by linpower.localnet (Postfix, from userid 1000) id 3CE5B2006D8; Sat, 23 May 2020 22:17:12 +0200 (CEST) From: =?utf-8?q?Volker_R=C3=BCmelin?= To: Gerd Hoffmann Subject: [PATCH] audio/mixeng: fix clang 10+ warning Date: Sat, 23 May 2020 22:17:12 +0200 Message-Id: <20200523201712.23908-1-vr_qemu@t-online.de> X-Mailer: git-send-email 2.26.1 In-Reply-To: <6231bee7-8d72-fe5c-9b73-cf27f57ff379@t-online.de> References: <6231bee7-8d72-fe5c-9b73-cf27f57ff379@t-online.de> MIME-Version: 1.0 X-ID: ESXGesZ-8huk1nGyLyIUmycUY9WnlJQ2t5J-4u5oRwPXne6C1HZOCXTCHcKsanbgwq X-TOI-EXPURGATEID: 150726::1590265032-00005513-B1C54894/0/0 CLEAN NORMAL X-TOI-MSGID: 60f53d3e-e19f-4d17-ad24-8e7628cbb6e8 Received-SPF: none client-ip=194.25.134.82; envelope-from=volker.ruemelin@t-online.de; helo=mailout05.t-online.de X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/23 16:17:13 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Alexander Bulekov , Richard Henderson , =?utf-8?q?Philippe_Mathie?= =?utf-8?q?u-Daud=C3=A9?= , QEMU Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" The code in CONV_NATURAL_FLOAT() and CLIP_NATURAL_FLOAT() seems to use the constant 2^31-0.5 to convert float to integer and back. But the float type lacks the required precision and the constant used for the conversion is 2^31. This is equiva- lent to a [-1.f, 1.f] <-> [INT32_MIN, INT32_MAX + 1] mapping. This patch explicitly writes down the used constant. The compiler generated code doesn't change. The constant 2^31 has an exact float representation and the clang 10 compiler stops complaining about an implicit int to float conversion with a changed value. A few notes: - The conversion of 1.f to INT32_MAX + 1 doesn't overflow. The type of the destination variable is int64_t. - At a later stage one of the clip_* functions in audio/mixeng_template.h limits INT32_MAX + 1 to the integer range. - The clip_natural_float_* functions in audio/mixeng.c convert INT32_MAX and INT32_MAX + 1 to 1.f. Buglink: https://bugs.launchpad.net/bugs/1878627 Signed-off-by: Volker Rümelin --- audio/mixeng.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/audio/mixeng.c b/audio/mixeng.c index 739a500449..924dcb858a 100644 --- a/audio/mixeng.c +++ b/audio/mixeng.c @@ -271,11 +271,12 @@ f_sample *mixeng_clip[2][2][2][3] = { #define CONV_NATURAL_FLOAT(x) (x) #define CLIP_NATURAL_FLOAT(x) (x) #else -static const float float_scale = UINT_MAX / 2.f; +/* macros to map [-1.f, 1.f] <-> [INT32_MIN, INT32_MAX + 1] */ +static const float float_scale = (int64_t)INT32_MAX + 1; #define CONV_NATURAL_FLOAT(x) ((x) * float_scale) #ifdef RECIPROCAL -static const float float_scale_reciprocal = 2.f / UINT_MAX; +static const float float_scale_reciprocal = 1.f / ((int64_t)INT32_MAX + 1); #define CLIP_NATURAL_FLOAT(x) ((x) * float_scale_reciprocal) #else #define CLIP_NATURAL_FLOAT(x) ((x) / float_scale)