From 41a6d2560500a202708e7b661b8b2ad432aee3a6 Mon Sep 17 00:00:00 2001
From: Ken Matsui <kmatsui@gcc.gnu.org>
Date: Thu, 8 Feb 2024 00:12:07 -0800
Subject: [PATCH] libstdc++: Use _GLIBCXX_USE_BUILTIN_TRAIT for is_same
Since is_same has a fallback native implementation, and
_GLIBCXX_HAVE_BUILTIN_IS_SAME does not support toggling which
implementation to use, we remove the _GLIBCXX_HAVE_BUILTIN_IS_SAME
definition and use _GLIBCXX_USE_BUILTIN_TRAIT instead.
libstdc++-v3/ChangeLog:
* include/bits/c++config (_GLIBCXX_HAVE_BUILTIN_IS_SAME):
Removed.
* include/std/type_traits (is_same): Use
_GLIBCXX_USE_BUILTIN_TRAIT instead of
_GLIBCXX_HAVE_BUILTIN_IS_SAME.
(is_same_v): Likewise.
Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
Reviewed-by: Patrick Palka <ppalka@redhat.com>
Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
---
libstdc++-v3/include/bits/c++config | 4 ----
libstdc++-v3/include/std/type_traits | 9 +++++----
2 files changed, 5 insertions(+), 8 deletions(-)
diff --git a/libstdc++-v3/include/bits/c++config b/libstdc++-v3/include/bits/c++config
index ad07ce92d5f4..b57e3f338e92 100644
--- a/libstdc++-v3/include/bits/c++config
+++ b/libstdc++-v3/include/bits/c++config
@@ -845,10 +845,6 @@ namespace __gnu_cxx
# define _GLIBCXX_HAVE_BUILTIN_IS_AGGREGATE 1
#endif
-#if _GLIBCXX_HAS_BUILTIN(__is_same)
-# define _GLIBCXX_HAVE_BUILTIN_IS_SAME 1
-#endif
-
#if _GLIBCXX_HAS_BUILTIN(__builtin_launder)
# define _GLIBCXX_HAVE_BUILTIN_LAUNDER 1
#endif
diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
index a9bb2806ca9c..21402fd8c132 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -1470,16 +1470,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// Type relations.
/// is_same
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_same)
template<typename _Tp, typename _Up>
struct is_same
-#ifdef _GLIBCXX_HAVE_BUILTIN_IS_SAME
: public __bool_constant<__is_same(_Tp, _Up)>
+ { };
#else
+ template<typename _Tp, typename _Up>
+ struct is_same
: public false_type
-#endif
{ };
-#ifndef _GLIBCXX_HAVE_BUILTIN_IS_SAME
template<typename _Tp>
struct is_same<_Tp, _Tp>
: public true_type
@@ -3496,7 +3497,7 @@ template <typename _Tp>
template <typename _Tp, unsigned _Idx>
inline constexpr size_t extent_v<_Tp[], _Idx> = extent_v<_Tp, _Idx - 1>;
-#ifdef _GLIBCXX_HAVE_BUILTIN_IS_SAME
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_same)
template <typename _Tp, typename _Up>
inline constexpr bool is_same_v = __is_same(_Tp, _Up);
#else
--
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