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 929433858C39 for ; Wed, 10 Apr 2024 08:50:52 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 929433858C39 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 929433858C39 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1712739054; cv=none; b=RvglDH/lB8uwXWK3z5hZtKV0LlXtKU3LxqKjYoNcJ/E6gimhbbk438bKYILvCndG1rv2AN2bF+z8/ElLzsFc9W7OJi5mboCxl0P1uqVMLlMm2XY4hxPCdR4MXqUmWxvqJh2/FgJfES3UoTi8Bl6hfqe7o2htzirn5eYmz7Nz0/k= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1712739054; c=relaxed/simple; bh=+pr+1zeJb/wng0j1AtKsSqg/7QoJsuxNxuB0sOTaFbU=; h=DKIM-Signature:From:To:Subject:Date:Message-ID:MIME-Version; b=Hugymn6RclRV+g2UTU3w88BXTuobwsdGH/5BZs/5nA8DUYvasGMxQgkPGVSLxFOzt5b6fzZ1/eucEnsMvSegAbvkhY+KPIpbprHs8yUsM8qmcktqLZIBYaB5loMcrprmDBDERnV671PBSoQYeew/IKkTO17N5ohLY+hvZn+o7Qo= ARC-Authentication-Results: i=1; server2.sourceware.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1712739052; 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: in-reply-to:in-reply-to:references:references; bh=ptTJ8TYFf8S8nHiNtE6JNU7+tD5c82lHIoB96MYdFmk=; b=Ac8oXDqO291Yu3pMdFzTrHmCHMyGxbWmLKGbNTc6e4UQPNFOy8slC2C7aSXNLGaFIpACXP HOWqIXnJZVwqsn6DvRb/pps8SrV+NwjLwSZ3uLeILZshC16+xxyC9Yg+ecjxkgXipndUl4 Dd0WLmzWhzfpCTS2dhqxRUxyTX/Vqfs= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-657-NswFvJEiODC7IvxK-L58bQ-1; Wed, 10 Apr 2024 04:50:49 -0400 X-MC-Unique: NswFvJEiODC7IvxK-L58bQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id EE4EF29ABA04; Wed, 10 Apr 2024 08:50:48 +0000 (UTC) Received: from localhost (unknown [10.42.28.163]) by smtp.corp.redhat.com (Postfix) with ESMTP id BD98C1C06667; Wed, 10 Apr 2024 08:50:48 +0000 (UTC) From: Jonathan Wakely To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org Subject: [PATCH 2/4] libstdc++: Add std::reference_wrapper comparison operators for C++26 Date: Wed, 10 Apr 2024 09:45:54 +0100 Message-ID: <20240410085039.267589-2-jwakely@redhat.com> In-Reply-To: <20240410085039.267589-1-jwakely@redhat.com> References: <20240410085039.267589-1-jwakely@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 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=-12.8 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,GIT_PATCH_0,KAM_NUMSUBJECT,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL,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: Tested x86_64-linux. Since this only affects C++26 it seems OK for trunk now. -- >8 -- This C++26 change was just approved in Tokyo, in P2944R3. It adds operator== and operator<=> overloads to std::reference_wrapper. The operator<=> overloads in the paper cause compilation errors for any type without <=> so they're implemented here with deduced return types and constrained by a requires clause. libstdc++-v3/ChangeLog: * include/bits/refwrap.h (reference_wrapper): Add comparison operators as proposed by P2944R3. * include/bits/version.def (reference_wrapper): Define. * include/bits/version.h: Regenerate. * include/std/functional: Enable feature test macro. * testsuite/20_util/reference_wrapper/compare.cc: New test. --- libstdc++-v3/include/bits/refwrap.h | 45 +++++++++ libstdc++-v3/include/bits/version.def | 8 ++ libstdc++-v3/include/bits/version.h | 10 ++ libstdc++-v3/include/std/functional | 1 + .../20_util/reference_wrapper/compare.cc | 95 +++++++++++++++++++ 5 files changed, 159 insertions(+) create mode 100644 libstdc++-v3/testsuite/20_util/reference_wrapper/compare.cc diff --git a/libstdc++-v3/include/bits/refwrap.h b/libstdc++-v3/include/bits/refwrap.h index 2d4338b718f..fd1cc2b63e6 100644 --- a/libstdc++-v3/include/bits/refwrap.h +++ b/libstdc++-v3/include/bits/refwrap.h @@ -38,6 +38,10 @@ #include #include // for unary_function and binary_function +#if __glibcxx_reference_wrapper >= 202403L // >= C++26 +# include +#endif + namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION @@ -358,6 +362,47 @@ _GLIBCXX_MEM_FN_TRAITS(&& noexcept, false_type, true_type) #endif return std::__invoke(get(), std::forward<_Args>(__args)...); } + +#if __glibcxx_reference_wrapper >= 202403L // >= C++26 + // [refwrap.comparisons], comparisons + [[nodiscard]] + friend constexpr bool + operator==(reference_wrapper __x, reference_wrapper __y) + requires requires { { __x.get() == __y.get() } -> convertible_to; } + { return __x.get() == __y.get(); } + + [[nodiscard]] + friend constexpr bool + operator==(reference_wrapper __x, const _Tp& __y) + requires requires { { __x.get() == __y } -> convertible_to; } + { return __x.get() == __y; } + + [[nodiscard]] + friend constexpr bool + operator==(reference_wrapper __x, reference_wrapper __y) + requires (!is_const_v<_Tp>) + && requires { { __x.get() == __y.get() } -> convertible_to; } + { return __x.get() == __y.get(); } + + [[nodiscard]] + friend constexpr auto + operator<=>(reference_wrapper __x, reference_wrapper<_Tp> __y) + requires requires { __detail::__synth3way(__x.get(), __y.get()); } + { return __detail::__synth3way(__x.get(), __y.get()); } + + [[nodiscard]] + friend constexpr auto + operator<=>(reference_wrapper __x, const _Tp& __y) + requires requires { __detail::__synth3way(__x.get(), __y); } + { return __detail::__synth3way(__x.get(), __y); } + + [[nodiscard]] + friend constexpr auto + operator<=>(reference_wrapper __x, reference_wrapper __y) + requires (!is_const_v<_Tp>) + && requires { __detail::__synth3way(__x.get(), __y.get()); } + { return __detail::__synth3way(__x.get(), __y.get()); } +#endif }; #if __cpp_deduction_guides diff --git a/libstdc++-v3/include/bits/version.def b/libstdc++-v3/include/bits/version.def index 5ad44941bff..5c0477fb61e 100644 --- a/libstdc++-v3/include/bits/version.def +++ b/libstdc++-v3/include/bits/version.def @@ -1760,6 +1760,14 @@ ftms = { }; }; +ftms = { + name = reference_wrapper; + values = { + v = 202403; + cxxmin = 26; + }; +}; + ftms = { name = saturation_arithmetic; values = { diff --git a/libstdc++-v3/include/bits/version.h b/libstdc++-v3/include/bits/version.h index 460a3e0116a..65e708c73fb 100644 --- a/libstdc++-v3/include/bits/version.h +++ b/libstdc++-v3/include/bits/version.h @@ -1963,6 +1963,16 @@ #endif /* !defined(__cpp_lib_ratio) && defined(__glibcxx_want_ratio) */ #undef __glibcxx_want_ratio +#if !defined(__cpp_lib_reference_wrapper) +# if (__cplusplus > 202302L) +# define __glibcxx_reference_wrapper 202403L +# if defined(__glibcxx_want_all) || defined(__glibcxx_want_reference_wrapper) +# define __cpp_lib_reference_wrapper 202403L +# endif +# endif +#endif /* !defined(__cpp_lib_reference_wrapper) && defined(__glibcxx_want_reference_wrapper) */ +#undef __glibcxx_want_reference_wrapper + #if !defined(__cpp_lib_saturation_arithmetic) # if (__cplusplus > 202302L) # define __glibcxx_saturation_arithmetic 202311L diff --git a/libstdc++-v3/include/std/functional b/libstdc++-v3/include/std/functional index 766558b3ce0..99364286a72 100644 --- a/libstdc++-v3/include/std/functional +++ b/libstdc++-v3/include/std/functional @@ -83,6 +83,7 @@ #define __glibcxx_want_move_only_function #define __glibcxx_want_not_fn #define __glibcxx_want_ranges +#define __glibcxx_want_reference_wrapper #define __glibcxx_want_transparent_operators #include diff --git a/libstdc++-v3/testsuite/20_util/reference_wrapper/compare.cc b/libstdc++-v3/testsuite/20_util/reference_wrapper/compare.cc new file mode 100644 index 00000000000..039c9d26496 --- /dev/null +++ b/libstdc++-v3/testsuite/20_util/reference_wrapper/compare.cc @@ -0,0 +1,95 @@ +// { dg-do compile { target c++26 } } + + +#include + +#ifndef __cpp_lib_reference_wrapper +# error "Feature-test macro for reference_wrapper missing" +#elif __cpp_lib_reference_wrapper != 202403 +# error "Feature-test macro for reference_wrapper has wrong value" +#endif + +// P2944R3 Comparisons for reference_wrapper + +auto check(int i, std::reference_wrapper r) -> bool { + return i == r; +} + +template using Ref = std::reference_wrapper; + +template +concept ref_equality_comparable += requires (T a, T const ca, Ref r, Ref cr) { + // the usual T is equality-comparable with itself + a == a; + a == ca; + ca == ca; + + // Ref is equality-comparable with itself + r == r; + r == cr; + cr == cr; + + // T and Ref are equality-comparable + a == r; + a == cr; + ca == r; + ca == cr; +}; + +static_assert( ref_equality_comparable ); + +struct A { + auto operator==(A const&) const -> bool { return true; } +}; + +struct B { + friend auto operator==(B const&, B const&) -> bool { return true; } +}; + +template +struct C { + friend auto operator==(C const&, C const&) -> bool { return true; } +}; + +template +struct D { }; +template +auto operator==(D const&, D const&) -> bool { return true; } + +static_assert(ref_equality_comparable); +static_assert(ref_equality_comparable); +static_assert(ref_equality_comparable); +static_assert(ref_equality_comparable>); +static_assert(ref_equality_comparable>); +#include +static_assert(ref_equality_comparable); + +template +struct ValArray { + friend auto operator==(ValArray const&, ValArray const&) -> ValArray { + return {}; + } +}; + +void f(ValArray v) { + // this is valid and has type ValArray + v == v; + + // this is also valid today and has the same type + std::ref(v) == std::ref(v); +} + +struct ComparesAsInt { + friend auto operator==(ComparesAsInt, ComparesAsInt) -> int; +}; + +auto f(std::reference_wrapper a, + std::reference_wrapper b) { + // today: compiles and returns int + // proposed: compiles and returns bool + return a == b; +} + +ComparesAsInt& c(); +static_assert( std::is_same_v ); -- 2.44.0