From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by sourceware.org (Postfix) with ESMTPS id 76E903858D39 for ; Tue, 20 Sep 2022 08:26:31 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 76E903858D39 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1663662391; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=9vw3XFvtcHwPeK8nWCtVlCbJZ07dHd7saradh1hAjp0=; b=NDHEiiN3VNq/2dbmRkhaPNm/UpxUDJgeTA4j3qxpe0geb7dBmTQcayjnc0pGkb77tc5xjP 7/XSNOIgylNsGIpCsU8cAxXkaiy02496mxhmf3Vd8jCziOTc7thsVilY17xryKdmcMjQUe taw9+X/OQkL51XXHc2a2Hbu/VXaupnQ= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-263-Ofh9yqQ3OFWp-i2vC11AGw-1; Tue, 20 Sep 2022 04:26:25 -0400 X-MC-Unique: Ofh9yqQ3OFWp-i2vC11AGw-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 46AFE185A7A8; Tue, 20 Sep 2022 08:26:25 +0000 (UTC) Received: from tucnak.zalov.cz (unknown [10.39.192.194]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 01BF0492B05; Tue, 20 Sep 2022 08:26:24 +0000 (UTC) Received: from tucnak.zalov.cz (localhost [127.0.0.1]) by tucnak.zalov.cz (8.17.1/8.17.1) with ESMTPS id 28K8QLp2668247 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Tue, 20 Sep 2022 10:26:22 +0200 Received: (from jakub@localhost) by tucnak.zalov.cz (8.17.1/8.17.1/Submit) id 28K8QLcI668246; Tue, 20 Sep 2022 10:26:21 +0200 Date: Tue, 20 Sep 2022 10:26:21 +0200 From: Jakub Jelinek To: Aldy Hernandez Cc: Richard Biener , Richard Henderson , GCC patches Subject: Re: [PATCH] frange: flush denormals to zero for -funsafe-math-optimizations. Message-ID: Reply-To: Jakub Jelinek References: <20220917082403.1573721-1-aldyh@redhat.com> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Spam-Status: No, score=-4.0 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_LOW,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On Tue, Sep 20, 2022 at 07:22:03AM +0200, Aldy Hernandez wrote: > > > Jakub actually suggested something completely different...just set +0 > > > always for !HONOR_SIGNED_ZEROS. > > > > Hmm, but the [-1, -0.] with known sign becomes [-1, +0.] with unknown sign? > > Huh. I guess that's true. Does that happen often enough in practice Sure, if you -fno-signed-zeros/-ffast-math and some variable can be zero, copysign/signbit is undefined. The option basically asserts you don't care about it... Jakub