From: Jonathan Wakely <jwakely@redhat.com>
To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org
Cc: Marek Polacek <polacek@redhat.com>, Jason Merrill <jason@redhat.com>
Subject: [PATCH] c++: Enable __has_builtin for new reference binding built-ins
Date: Tue, 19 Jul 2022 14:11:02 +0100 [thread overview]
Message-ID: <20220719131102.2469016-1-jwakely@redhat.com> (raw)
Tested x86_64-linux, OK for trunk?
-- >8 --
The new built-ins need to be detectable using __has_builtin, and the
library should use that to check for them.
This fixes an error with Clang when C++23 is enabled.
gcc/cp/ChangeLog:
* cp-objcp-common.cc (names_builtin_p): Return true for
RID_REF_CONSTRUCTS_FROM_TEMPORARY and
RID_REF_CONVERTS_FROM_TEMPORARY.
libstdc++-v3/ChangeLog:
* include/std/type_traits (__cpp_lib_reference_from_temporary)
(reference_constructs_from_temporary)
(reference_converts_from_temporary): Only define when the
built-ins are available.
---
gcc/cp/cp-objcp-common.cc | 2 ++
libstdc++-v3/include/std/type_traits | 4 ++++
2 files changed, 6 insertions(+)
diff --git a/gcc/cp/cp-objcp-common.cc b/gcc/cp/cp-objcp-common.cc
index 0b70d5567e4..4079a4b4aec 100644
--- a/gcc/cp/cp-objcp-common.cc
+++ b/gcc/cp/cp-objcp-common.cc
@@ -461,6 +461,8 @@ names_builtin_p (const char *name)
case RID_IS_ASSIGNABLE:
case RID_IS_CONSTRUCTIBLE:
case RID_UNDERLYING_TYPE:
+ case RID_REF_CONSTRUCTS_FROM_TEMPORARY:
+ case RID_REF_CONVERTS_FROM_TEMPORARY:
return true;
default:
break;
diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
index b1a1deecf66..14b029cec64 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -3505,6 +3505,9 @@ template<typename _Ret, typename _Fn, typename... _Args>
template<typename _Tp>
inline constexpr bool is_scoped_enum_v = is_scoped_enum<_Tp>::value;
+#if __has_builtin(__reference_constructs_from_temporary) \
+ && __has_builtin(__reference_converts_from_temporary)
+
#define __cpp_lib_reference_from_temporary 202202L
/// True if _Tp is a reference type, a _Up value can be bound to _Tp in
@@ -3544,6 +3547,7 @@ template<typename _Ret, typename _Fn, typename... _Args>
template<typename _Tp, typename _Up>
inline constexpr bool reference_converts_from_temporary_v
= reference_converts_from_temporary<_Tp, _Up>::value;
+#endif // __has_builtin for reference_from_temporary
#endif // C++23
#if _GLIBCXX_HAVE_IS_CONSTANT_EVALUATED
--
2.34.3
next reply other threads:[~2022-07-19 13:11 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-19 13:11 Jonathan Wakely [this message]
2022-07-19 13:30 ` Marek Polacek
2022-07-19 14:05 ` Jason Merrill
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