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[v20,05/40] libstdc++: Optimize is_const trait performance

Message ID	20231016001227.2717180-6-kmatsui@gcc.gnu.org
State	Accepted
Headers	Received-SPF: pass (google.com: domain of gcc-patches-bounces+ouuuleilei=gmail.com@gcc.gnu.org designates 2620:52:3:1:0:246e:9693:128c as permitted sender) client-ip=2620:52:3:1:0:246e:9693:128c; DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 1BAAA3858419 From: Ken Matsui <kmatsui@gcc.gnu.org> To: gcc-patches@gcc.gnu.org Cc: libstdc++@gcc.gnu.org, Ken Matsui <kmatsui@gcc.gnu.org> Subject: [PATCH v20 05/40] libstdc++: Optimize is_const trait performance Date: Sun, 15 Oct 2023 17:09:49 -0700 Message-ID: <20231016001227.2717180-6-kmatsui@gcc.gnu.org> In-Reply-To: <20231016001227.2717180-1-kmatsui@gcc.gnu.org> References: <20231013223957.1634024-1-kmatsui@gcc.gnu.org> <20231016001227.2717180-1-kmatsui@gcc.gnu.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: list Errors-To: gcc-patches-bounces+ouuuleilei=gmail.com@gcc.gnu.org X-getmail-retrieved-from-mailbox: INBOX
Series	Optimize type traits performance \| [v20,00/40] Optimize type traits performance [v20,01/40] c++: Sort built-in traits alphabetically [v20,02/40] c-family, c++: Look up built-in traits via identifier node [v20,03/40] c++: Accept the use of built-in trait identifiers [v20,04/40] c++: Implement __is_const built-in trait [v20,05/40] libstdc++: Optimize is_const trait performance [v20,06/40] c++: Implement __is_volatile built-in trait [v20,07/40] libstdc++: Optimize is_volatile trait performance [v20,08/40] c++: Implement __is_array built-in trait [v20,09/40] libstdc++: Optimize is_array trait performance [v20,10/40] c++: Implement __is_unbounded_array built-in trait [v20,11/40] libstdc++: Optimize is_unbounded_array trait performance [v20,12/40] c++: Implement __is_bounded_array built-in trait [v20,13/40] libstdc++: Optimize is_bounded_array trait performance [v20,14/40] c++: Implement __is_scoped_enum built-in trait [v20,15/40] libstdc++: Optimize is_scoped_enum trait performance [v20,16/40] c++: Implement __is_member_pointer built-in trait [v20,17/40] libstdc++: Optimize is_member_pointer trait performance [v20,18/40] c++: Implement __is_member_function_pointer built-in trait [v20,19/40] libstdc++: Optimize is_member_function_pointer trait performance [v20,20/40] c++: Implement __is_member_object_pointer built-in trait [v20,21/40] libstdc++: Optimize is_member_object_pointer trait performance [v20,22/40] c++: Implement __is_reference built-in trait [v20,23/40] libstdc++: Optimize is_reference trait performance [v20,24/40] c++: Implement __is_function built-in trait [v20,25/40] libstdc++: Optimize is_function trait performance [v20,26/40] libstdc++: Optimize is_object trait performance [v20,27/40] c++: Implement __remove_pointer built-in trait [v20,28/40] libstdc++: Optimize remove_pointer trait performance [v20,29/40] c++: Implement __is_pointer built-in trait [v20,30/40] libstdc++: Optimize is_pointer trait performance [v20,31/40] c++: Implement __is_arithmetic built-in trait [v20,32/40] libstdc++: Optimize is_arithmetic trait performance [v20,33/40] libstdc++: Optimize is_fundamental trait performance [v20,34/40] libstdc++: Optimize is_compound trait performance [v20,35/40] c++: Implement __is_unsigned built-in trait [v20,36/40] libstdc++: Optimize is_unsigned trait performance [v20,37/40] c++: Implement __is_signed built-in trait [v20,38/40] libstdc++: Optimize is_signed trait performance [v20,39/40] c++: Implement __is_scalar built-in trait [v20,40/40] libstdc++: Optimize is_scalar trait performance

Checks

Context	Check	Description
snail/gcc-patch-check	success	Github commit url

Commit Message

Ken Matsui Oct. 16, 2023, 12:09 a.m. UTC

  This patch optimizes the performance of the is_const trait by dispatching to
the new __is_const built-in trait.

libstdc++-v3/ChangeLog:

	* include/std/type_traits (is_const): Use __is_const built-in trait.
	(is_const_v): Likewise.

Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
---
 libstdc++-v3/include/std/type_traits | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff mbox series

Patch

diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
index 677cd934b94..686e38e47c3 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -784,6 +784,12 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
   // Type properties.
 
   /// is_const
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_const)
+  template<typename _Tp>
+    struct is_const
+    : public __bool_constant<__is_const(_Tp)>
+    { };
+#else
   template<typename>
     struct is_const
     : public false_type { };
@@ -791,6 +797,7 @@  _GLIBCXX_BEGIN_NAMESPACE_VERSION
   template<typename _Tp>
     struct is_const<_Tp const>
     : public true_type { };
+#endif
 
   /// is_volatile
   template<typename>
@@ -3218,10 +3225,17 @@  template <typename _Tp>
   inline constexpr bool is_compound_v = is_compound<_Tp>::value;
 template <typename _Tp>
   inline constexpr bool is_member_pointer_v = is_member_pointer<_Tp>::value;
+
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_const)
+template <typename _Tp>
+  inline constexpr bool is_const_v = __is_const(_Tp);
+#else
 template <typename _Tp>
   inline constexpr bool is_const_v = false;
 template <typename _Tp>
   inline constexpr bool is_const_v<const _Tp> = true;
+#endif
+
 template <typename _Tp>
   inline constexpr bool is_volatile_v = false;
 template <typename _Tp>