[v5,4/6] libstdc++: use new built-in trait __is_function for std::is_function
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Commit Message
This patch gets std::is_function to dispatch to new built-in trait
__is_function.
libstdc++-v3/ChangeLog:
* include/std/type_traits (is_function): Use __is_function built-in
trait.
(is_function_v): Likewise.
Signed-off-by: Ken Matsui <kmatsui@cs.washington.edu>
---
libstdc++-v3/include/std/type_traits | 13 +++++++++++++
1 file changed, 13 insertions(+)
@@ -594,6 +594,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ };
/// is_function
+#if __has_builtin(__is_function)
+ template<typename _Tp>
+ struct is_function
+ : public __bool_constant<__is_function(_Tp)>
+ { };
+#else
template<typename _Tp>
struct is_function
: public __bool_constant<!is_const<const _Tp>::value> { };
@@ -605,6 +611,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _Tp>
struct is_function<_Tp&&>
: public false_type { };
+#endif
#define __cpp_lib_is_null_pointer 201309L
@@ -3197,8 +3204,14 @@ template <typename _Tp>
inline constexpr bool is_union_v = __is_union(_Tp);
template <typename _Tp>
inline constexpr bool is_class_v = __is_class(_Tp);
+
+#if __has_builtin(__is_function)
+template <typename _Tp>
+ inline constexpr bool is_function_v = __is_function(_Tp);
+#else
template <typename _Tp>
inline constexpr bool is_function_v = is_function<_Tp>::value;
+#endif
#if __has_builtin(__is_reference)
template <typename _Tp>