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[v16,18/26] libstdc++: Optimize std::add_rvalue_reference compilation performance

Message ID 20240502161614.3705912-19-kmatsui@gcc.gnu.org
State New
Headers show
Series Optimize more type traits | expand

Commit Message

Ken Matsui May 2, 2024, 4:13 p.m. UTC 
This patch optimizes the compilation performance of
std::add_rvalue_reference by dispatching to the new
__builtin_add_rvalue_reference trait.

libstdc++-v3/ChangeLog:

	* include/std/type_traits (add_rvalue_reference): Use
	__builtin_add_rvalue_reference trait.
	(__add_rvalue_reference_helper): Likewise.

Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
---
 libstdc++-v3/include/std/type_traits | 12 ++++++++++++
 1 file changed, 12 insertions(+)
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Patch

diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
index 4e97e45f130..36ac900605a 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -1185,6 +1185,11 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     };
 
   /// @cond undocumented
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__builtin_add_rvalue_reference)
+  template<typename _Tp>
+    struct __add_rvalue_reference_helper
+    { using type = __builtin_add_rvalue_reference(_Tp); };
+#else
   template<typename _Tp, typename = void>
     struct __add_rvalue_reference_helper
     { using type = _Tp; };
@@ -1192,6 +1197,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
   template<typename _Tp>
     struct __add_rvalue_reference_helper<_Tp, __void_t<_Tp&&>>
     { using type = _Tp&&; };
+#endif
 
   template<typename _Tp>
     using __add_rval_ref_t = typename __add_rvalue_reference_helper<_Tp>::type;
@@ -1748,9 +1754,15 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
 #endif
 
   /// add_rvalue_reference
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__builtin_add_rvalue_reference)
+  template<typename _Tp>
+    struct add_rvalue_reference
+    { using type = __builtin_add_rvalue_reference(_Tp); };
+#else
   template<typename _Tp>
     struct add_rvalue_reference
     { using type = __add_rval_ref_t<_Tp>; };
+#endif
 
 #if __cplusplus > 201103L
   /// Alias template for remove_reference