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 C607B3858D28 for ; Wed, 2 Nov 2022 09:39:42 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org C607B3858D28 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=1667381982; 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; bh=duvFFBYZzw7RIqKJI4WnQ6JAi9JwTDCIGbjG9CqgSZI=; b=cXNY/bNs8868dw7A2k2/42AXB3Qq97nP9uU8Gp3SYf9T+h40POFICJip4gD0PFVG/ZsDau VhFPrE+H25vG8aZ+ASe6t5QJa6/yg07I6uDBp42X24uHifOivXZK6LlcO1VOQ6Rq/nYYTL puPzAjlGGVteb3cIhjQLTLluPZWuTSM= 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-49-pFCrIyOaPrmlL-TGlumDTg-1; Wed, 02 Nov 2022 05:39:41 -0400 X-MC-Unique: pFCrIyOaPrmlL-TGlumDTg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 89C851C09B72 for ; Wed, 2 Nov 2022 09:39:40 +0000 (UTC) Received: from tucnak.zalov.cz (unknown [10.39.193.252]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4953140C94CE; Wed, 2 Nov 2022 09:39:40 +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 2A29dbSQ2091873 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Wed, 2 Nov 2022 10:39:38 +0100 Received: (from jakub@localhost) by tucnak.zalov.cz (8.17.1/8.17.1/Submit) id 2A29db382091872; Wed, 2 Nov 2022 10:39:37 +0100 Date: Wed, 2 Nov 2022 10:39:37 +0100 From: Jakub Jelinek To: Jonathan Wakely , Patrick Palka Cc: gcc-patches@gcc.gnu.org Subject: [PATCH] libstdc++: _Bfloat16 for Message-ID: Reply-To: Jakub Jelinek MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 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=-4.4 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE,TXREP 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: Hi! Jon pointed out that we have TODO: _Bfloat16 in . Right now _S_fp_fmt() returns _Binary16 for _Float16, __fp16 as well as __bf16 and it actually works because we don't have a special handling of _Binary16. So, either we could just document that, but I'm a little bit afraid if HPPA or MIPS don't start supporting _Float16 and/or __bf16. If they do, we have the #if defined __hppa__ || (defined __mips__ && !defined __mips_nan2008) // IEEE 754-1985 allowed the meaning of the quiet/signaling // bit to be reversed. Flip that to give desired ordering. if (__builtin_isnan(__x) && __builtin_isnan(__y)) { using _Int = decltype(__ix); constexpr int __nantype = __fmt == _Binary32 ? 22 : __fmt == _Binary64 ? 51 : __fmt == _Binary128 ? 111 : -1; constexpr _Int __bit = _Int(1) << __nantype; __ix ^= __bit; __iy ^= __bit; } #endif code, the only one where we actually care whether something is _Binary{32,64,128} (elsewhere we just care about the x86 and m68k 80bits or double double or just floating point type's sizeof) and we'd need to handle there _Binary16 and/or _Bfloat16. So this patch uses different enum for it even when it isn't needed right now, after all _Binary16 isn't needed either and we could just use _Binary32... Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? 2022-11-02 Jakub Jelinek * libsupc++/compare (_Strong_order::_Fp_fmt): Add _Bfloat16. (_Strong_order::_Bfloat16): New static data member. (_Strong_order::_S_fp_fmt): Return _Bfloat16 for std::bfloat16_t. --- libstdc++-v3/libsupc++/compare.jj 2022-05-09 09:09:21.196461093 +0200 +++ libstdc++-v3/libsupc++/compare 2022-11-01 22:13:16.771219615 +0100 @@ -672,7 +672,7 @@ namespace std _GLIBCXX_VISIBILITY(defaul _X86_80bit, // x86 80-bit extended precision _M68k_80bit, // m68k 80-bit extended precision _Dbldbl, // IBM 128-bit double-double - // TODO: _Bfloat16, + _Bfloat16, // std::bfloat16_t }; #ifndef __cpp_using_enum @@ -684,6 +684,7 @@ namespace std _GLIBCXX_VISIBILITY(defaul static constexpr _Fp_fmt _X86_80bit = _Fp_fmt::_X86_80bit; static constexpr _Fp_fmt _M68k_80bit = _Fp_fmt::_M68k_80bit; static constexpr _Fp_fmt _Dbldbl = _Fp_fmt::_Dbldbl; + static constexpr _Fp_fmt _Bfloat16 = _Fp_fmt::_Bfloat16; #endif // Identify the format used by a floating-point type. @@ -714,6 +715,10 @@ namespace std _GLIBCXX_VISIBILITY(defaul if constexpr (__is_same(_Tp, __float80)) return _X86_80bit; #endif +#ifdef __STDCPP_BFLOAT16_T__ + if constexpr (__is_same(_Tp, decltype(0.0bf16))) + return _Bfloat16; +#endif constexpr int __width = sizeof(_Tp) * __CHAR_BIT__; Jakub