From patchwork Tue May 26 07:56:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Gerd Hoffmann X-Patchwork-Id: 281908 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=-6.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED 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 4F967C433DF for ; Tue, 26 May 2020 08:01:49 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 1306720776 for ; Tue, 26 May 2020 08:01:49 +0000 (UTC) Authentication-Results: mail.kernel.org; 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Tue, 26 May 2020 07:56:46 +0000 (UTC) Received: from sirius.home.kraxel.org (ovpn-113-50.ams2.redhat.com [10.36.113.50]) by smtp.corp.redhat.com (Postfix) with ESMTP id 540F76ED99; Tue, 26 May 2020 07:56:42 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id 12AFD9DB0; Tue, 26 May 2020 09:56:40 +0200 (CEST) From: Gerd Hoffmann To: qemu-devel@nongnu.org Subject: [PULL 4/8] audio/mixeng: fix clang 10+ warning Date: Tue, 26 May 2020 09:56:35 +0200 Message-Id: <20200526075639.27949-5-kraxel@redhat.com> In-Reply-To: <20200526075639.27949-1-kraxel@redhat.com> References: <20200526075639.27949-1-kraxel@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=205.139.110.120; envelope-from=kraxel@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/05/26 01:19:28 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-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: =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , =?utf-8?q?Volker_R=C3=BCmelin?= , Markus Armbruster , Aleksandar Markovic , Gerd Hoffmann , Aleksandar Rikalo , Aurelien Jarno Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Volker Rümelin 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 Message-id: 20200523201712.23908-1-vr_qemu@t-online.de Signed-off-by: Gerd Hoffmann --- audio/mixeng.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/audio/mixeng.c b/audio/mixeng.c index 739a500449ce..924dcb858af5 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)