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 [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id B41D7385355A for ; Tue, 6 Sep 2022 12:06:47 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org B41D7385355A 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=1662466007; 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=tqGKuuC/jmSXSz4c5o6xGtPd3AbNWz/smeFoIp46lLI=; b=RVLrkeXIczUxjqzLDv8HcFh22SqG7hmhZJoP/UpT7DW+DNzetFkrG4MwSfceIT1AV/v6RY U6Tq6ePerscVMbp+rfrU3uraWvFuLPLhyiQxiiwc/WkAIlmeOssg3s9y4+C2YboCKD52ho yQTzdxrIiQrZz/+PHZD2tbpKtIMUcxE= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-252-qUnBPHMoNW62zh8qq6Iikw-1; Tue, 06 Sep 2022 08:06:44 -0400 X-MC-Unique: qUnBPHMoNW62zh8qq6Iikw-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 1DBFD1C06EC9; Tue, 6 Sep 2022 12:06:44 +0000 (UTC) Received: from tucnak.zalov.cz (unknown [10.39.192.41]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D0153492C3B; Tue, 6 Sep 2022 12:06:43 +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 286C6fO52017564 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Tue, 6 Sep 2022 14:06:41 +0200 Received: (from jakub@localhost) by tucnak.zalov.cz (8.17.1/8.17.1/Submit) id 286C6eHr2017563; Tue, 6 Sep 2022 14:06:40 +0200 Date: Tue, 6 Sep 2022 14:06:40 +0200 From: Jakub Jelinek To: Aldy Hernandez Cc: GCC patches , Richard Biener , Andrew MacLeod Subject: Re: [PATCH] Handle > INF and < INF correctly in range-op-float.cc Message-ID: Reply-To: Jakub Jelinek References: <20220906072901.3472801-1-aldyh@redhat.com> MIME-Version: 1.0 In-Reply-To: X-Scanned-By: MIMEDefang 2.85 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=-4.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_NONE,TXREP,T_SCC_BODY_TEXT_LINE autolearn=ham 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 06, 2022 at 01:47:43PM +0200, Aldy Hernandez wrote: > Question...for !HONOR_NANS or !HONOR_INFINITIES or whatever, say the > range for the domain is [-MIN, +MAX] for the min and max representable > numbers. What happens for MAX+1? Is that undefined? I wonder what > real.cc does for that. I'm afraid I have no idea. The formats without Inf/NaN are: spu_single_format vax_{f,d,g}_format arm_half_format Never had the "pleasure" to work with any of these. Looking at encode_vax_*, it seems both GCC internal inf and nan are most likely are encoded as maximum or minimum representable numbers (depending on sign), and encode_ieee_half for !fmt->has_inf does too (for !fmt->has_nans it seems to "encode" the nan mantissa bits into highest possible exponent). encode_ieee_single (for spu) uses maximum or minimum representable numbers for any infinities or nans. What they actually do at runtime is something I can't really check, but one would hope it is saturating... Jakub