This patch optimizes the performance of the is_unsigned trait by dispatching
to the new __is_unsigned built-in trait.
libstdc++-v3/ChangeLog:
* include/std/type_traits (is_unsigned): Use __is_unsigned built-in
trait.
(is_unsigned_v): Likewise.
Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
---
libstdc++-v3/include/std/type_traits | 13 +++++++++++++
1 file changed, 13 insertions(+)
@@ -1001,10 +1001,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ };
/// is_unsigned
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_unsigned)
+ template<typename _Tp>
+ struct is_unsigned
+ : public __bool_constant<__is_unsigned(_Tp)>
+ { };
+#else
template<typename _Tp>
struct is_unsigned
: public __and_<is_arithmetic<_Tp>, __not_<is_signed<_Tp>>>::type
{ };
+#endif
/// @cond undocumented
template<typename _Tp, typename _Up = _Tp&&>
@@ -3440,8 +3447,14 @@ template <typename _Tp>
template <typename _Tp>
inline constexpr bool is_signed_v = is_signed<_Tp>::value;
+
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_unsigned)
+template <typename _Tp>
+ inline constexpr bool is_unsigned_v = __is_unsigned(_Tp);
+#else
template <typename _Tp>
inline constexpr bool is_unsigned_v = is_unsigned<_Tp>::value;
+#endif
template <typename _Tp, typename... _Args>
inline constexpr bool is_constructible_v = __is_constructible(_Tp, _Args...);