[v2,2/2] libstdc++: use new built-in trait __is_volatile
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Commit Message
This patch lets libstdc++ use new built-in trait __is_volatile.
libstdc++-v3/ChangeLog:
* include/std/type_traits (is_volatile): Use __is_volatile built-in
trait.
(is_volatile_v): Likewise.
Signed-off-by: Ken Matsui <kmatsui@cs.washington.edu>
---
libstdc++-v3/include/std/type_traits | 13 +++++++++++++
1 file changed, 13 insertions(+)
@@ -773,6 +773,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
: public true_type { };
/// is_volatile
+#if __has_builtin(__is_volatile)
+ template<typename _Tp>
+ struct is_volatile
+ : public __bool_constant<__is_volatile(_Tp)>
+ { };
+#else
template<typename>
struct is_volatile
: public false_type { };
@@ -780,6 +786,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
template<typename _Tp>
struct is_volatile<_Tp volatile>
: public true_type { };
+#endif
/// is_trivial
template<typename _Tp>
@@ -3214,10 +3221,16 @@ template <typename _Tp>
inline constexpr bool is_const_v = false;
template <typename _Tp>
inline constexpr bool is_const_v<const _Tp> = true;
+
+#if __has_builtin(__is_volatile)
+template <typename _Tp>
+ inline constexpr bool is_volatile_v = __is_volatile(_Tp);
+#else
template <typename _Tp>
inline constexpr bool is_volatile_v = false;
template <typename _Tp>
inline constexpr bool is_volatile_v<volatile _Tp> = true;
+#endif
template <typename _Tp>
inline constexpr bool is_trivial_v = __is_trivial(_Tp);