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[v7,16/22] libstdc++: Optimize std::add_lvalue_reference compilation performance

Message ID 20240219135129.3635809-16-kmatsui@gcc.gnu.org
State Superseded
Headers
Series [v7,01/22] c++: Implement __is_const built-in trait |

Commit Message

Ken Matsui Feb. 19, 2024, 1:51 p.m. UTC 
  This patch optimizes the compilation performance of
std::add_lvalue_reference by dispatching to the new
__add_lvalue_reference built-in trait.

libstdc++-v3/ChangeLog:

	* include/std/type_traits (add_lvalue_reference): Use
	__add_lvalue_reference built-in trait.
	(__add_lvalue_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 34475e6279a..17bf47d59d3 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -1157,6 +1157,11 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
     };
 
   /// @cond undocumented
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__add_lvalue_reference)
+  template<typename _Tp>
+    struct __add_lvalue_reference_helper
+    { using type = __add_lvalue_reference(_Tp); };
+#else
   template<typename _Tp, typename = void>
     struct __add_lvalue_reference_helper
     { using type = _Tp; };
@@ -1164,6 +1169,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
   template<typename _Tp>
     struct __add_lvalue_reference_helper<_Tp, __void_t<_Tp&>>
     { using type = _Tp&; };
+#endif
 
   template<typename _Tp>
     using __add_lval_ref_t = typename __add_lvalue_reference_helper<_Tp>::type;
@@ -1731,9 +1737,15 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
 #endif
 
   /// add_lvalue_reference
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__add_lvalue_reference)
+  template<typename _Tp>
+    struct add_lvalue_reference
+    { using type = __add_lvalue_reference(_Tp); };
+#else
   template<typename _Tp>
     struct add_lvalue_reference
     { using type = __add_lval_ref_t<_Tp>; };
+#endif
 
   /// add_rvalue_reference
   template<typename _Tp>