[PATCH 02/14] libstdc++: Optimize std::is_integral compilation performance

[Ken Matsui]

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

libstdc++-v3/ChangeLog:

        * include/std/type_traits (is_integral): Use __is_integral
        built-in trait.
        (is_integral_v): Likewise.

Signed-off-by: Ken Matsui <kmat...@gcc.gnu.org>
---
 libstdc++-v3/include/std/type_traits | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/libstdc++-v3/include/std/type_traits 
b/libstdc++-v3/include/std/type_traits
index 1cec0822b73..afa281d9cc4 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -334,6 +334,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     struct is_void<const volatile void>
     : public true_type { };
 
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_integral)
+  /// is_integral
+  template<typename _Tp>
+    struct is_integral
+    : public __bool_constant<__is_integral(_Tp)>
+    { };
+#else
   /// @cond undocumented
   template<typename>
     struct __is_integral_helper
@@ -461,6 +468,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     struct is_integral
     : public __is_integral_helper<__remove_cv_t<_Tp>>::type
     { };
+#endif
 
   /// @cond undocumented
   template<typename>
@@ -3221,8 +3229,15 @@ template <typename _Tp>
   inline constexpr bool is_void_v = is_void<_Tp>::value;
 template <typename _Tp>
   inline constexpr bool is_null_pointer_v = is_null_pointer<_Tp>::value;
+
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_integral)
+template <typename _Tp>
+  inline constexpr bool is_integral_v = __is_integral(_Tp);
+#else
 template <typename _Tp>
   inline constexpr bool is_integral_v = is_integral<_Tp>::value;
+#endif
+
 template <typename _Tp>
   inline constexpr bool is_floating_point_v = is_floating_point<_Tp>::value;
 
-- 
2.43.0