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 C829D396E057 for ; Wed, 16 Nov 2022 20:59:54 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org C829D396E057 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=1668632394; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=npBLG/yyKAjzQfX9wXyYuVvOmF96j/uJSwtKHVtk5n4=; b=VvRspbLExtqGAT5IpGDz10zxRzBwEvE1hklHd9XxOTS79bXu3V8aJPaghCAf04zKIwCtSg zow7dvKyyjOKjLdiCAvGQDk193pEZr3MZnBiH6C34TGCIohIfWiT/ES7fRL8tpQ/omYK15 FScC4qHVJ6RtXFPBiCpTe4J05RDMT7w= 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-26-IoBgBTMyPbiMHozBjBRWGw-1; Wed, 16 Nov 2022 15:59:53 -0500 X-MC-Unique: IoBgBTMyPbiMHozBjBRWGw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 1845A862FDF; Wed, 16 Nov 2022 20:59:53 +0000 (UTC) Received: from localhost (unknown [10.33.36.199]) by smtp.corp.redhat.com (Postfix) with ESMTP id D5BA9140EBF3; Wed, 16 Nov 2022 20:59:52 +0000 (UTC) From: Jonathan Wakely To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org Subject: [committed] libstdc++: Disable std::format of _Float128 if std::to_chars is innaccurate Date: Wed, 16 Nov 2022 20:59:50 +0000 Message-Id: <20221116205950.1420057-1-jwakely@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-11.8 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,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: Tested x86_64-linux. Pushed to trunk. -- >8 -- This restricts std::format support for _Float128 (and __float128) to targets where glibc provides __strfromf128 and so can give correct output. libstdc++-v3/ChangeLog: * include/std/format [__FLT128_DIG__] (_GLIBCXX_FORMAT_F128): Only support formatting _Float128 when glibc provides the functionality needed for accurate std::to_chars. --- libstdc++-v3/include/std/format | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/libstdc++-v3/include/std/format b/libstdc++-v3/include/std/format index 204a1710aca..fb29f7e7835 100644 --- a/libstdc++-v3/include/std/format +++ b/libstdc++-v3/include/std/format @@ -1235,13 +1235,13 @@ namespace __format using __float128_t = long double; # define _GLIBCXX_FORMAT_F128 1 -#elif __FLT128_DIG__ && defined(__GLIBC_PREREQ) // see floating_to_chars.cc +#elif __FLT128_DIG__ && defined(_GLIBCXX_HAVE_FLOAT128_MATH) // Format 128-bit floating-point types using _Float128. using __float128_t = _Float128; # define _GLIBCXX_FORMAT_F128 2 -# if __cplusplus == 202002L || !defined(_GLIBCXX_HAVE_FLOAT128_MATH) +# if __cplusplus == 202002L // These overloads exist in the library, but are not declared for C++20. // Make them available as std::__format::to_chars. to_chars_result -- 2.38.1