From 61d6dee992fdfa350a0c6d2a8151ec6e2844c419 Mon Sep 17 00:00:00 2001
From: Ken Matsui <kmatsui@gcc.gnu.org>
Date: Mon, 20 Mar 2023 14:05:48 -0700
Subject: [PATCH] libstdc++: Optimize std::remove_pointer compilation
 performance

This patch optimizes the compilation performance of std::remove_pointer
by dispatching to the new remove_pointer built-in trait.

libstdc++-v3/ChangeLog:

	* include/std/type_traits (remove_pointer): Use __remove_pointer
	built-in trait.

Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
---
 libstdc++-v3/include/std/type_traits | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
index 2979d79a8014..f00c07f94f9c 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -2089,6 +2089,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
   // Pointer modifications.
 
+  /// remove_pointer
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__remove_pointer)
+  template<typename _Tp>
+    struct remove_pointer
+    { using type = __remove_pointer(_Tp); };
+#else
   template<typename _Tp, typename>
     struct __remove_pointer_helper
     { using type = _Tp; };
@@ -2097,11 +2103,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     struct __remove_pointer_helper<_Tp, _Up*>
     { using type = _Up; };
 
-  /// remove_pointer
   template<typename _Tp>
     struct remove_pointer
     : public __remove_pointer_helper<_Tp, __remove_cv_t<_Tp>>
     { };
+#endif
 
   template<typename _Tp, typename = void>
     struct __add_pointer_helper
-- 
2.47.2