[gcc r14-3174] libstdc++: Use __bool_constant entirely

[Ken Matsui]

https://gcc.gnu.org/g:066c260ad09dde95f43e503f7242b011d17a10f6

commit r14-3174-g066c260ad09dde95f43e503f7242b011d17a10f6
Author: Ken Matsui <kmatsui@gcc.gnu.org>
Date:   Fri Jul 14 19:55:35 2023 -0700

    libstdc++: Use __bool_constant entirely
    
    This patch uses __bool_constant entirely instead of integral_constant<bool>
    in the type_traits header, specifically for true_type, false_type,
    and bool_constant.
    
    libstdc++-v3/ChangeLog:
    
            * include/std/type_traits (true_type): Use __bool_constant
            instead.
            (false_type): Likewise.
            (bool_constant): Likewise.
    
    Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
    Reviewed-by: Jonathan Wakely <jwakely@redhat.com>

Diff:
---
 libstdc++-v3/include/std/type_traits | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
index 9f086992ebcc..7dc5791a7c5e 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -78,24 +78,24 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     constexpr _Tp integral_constant<_Tp, __v>::value;
 #endif
 
-  /// The type used as a compile-time boolean with true value.
-  using true_type =  integral_constant<bool, true>;
-
-  /// The type used as a compile-time boolean with false value.
-  using false_type = integral_constant<bool, false>;
-
   /// @cond undocumented
   /// bool_constant for C++11
   template<bool __v>
     using __bool_constant = integral_constant<bool, __v>;
   /// @endcond
 
+  /// The type used as a compile-time boolean with true value.
+  using true_type =  __bool_constant<true>;
+
+  /// The type used as a compile-time boolean with false value.
+  using false_type = __bool_constant<false>;
+
 #if __cplusplus >= 201703L
 # define __cpp_lib_bool_constant 201505L
   /// Alias template for compile-time boolean constant types.
   /// @since C++17
   template<bool __v>
-    using bool_constant = integral_constant<bool, __v>;
+    using bool_constant = __bool_constant<__v>;
 #endif
 
   // Metaprogramming helper types.