https://gcc.gnu.org/g:014879ea4c86b3b8ab6b61a1226ee5b31e816c8b
commit r15-1289-g014879ea4c86b3b8ab6b61a1226ee5b31e816c8b
Author: Ken Matsui <kmat...@gcc.gnu.org>
Date: Wed Jul 12 13:43:44 2023 -0700
libstdc++: Optimize std::is_pointer compilation performance
This patch optimizes the compilation performance of std::is_pointer
by dispatching to the new __is_pointer built-in trait.
libstdc++-v3/ChangeLog:
* include/bits/cpp_type_traits.h (__is_pointer): Use
__is_pointer built-in trait.
* include/std/type_traits (is_pointer): Likewise. Optimize its
implementation.
(is_pointer_v): Likewise.
Co-authored-by: Jonathan Wakely <jwak...@redhat.com>
Signed-off-by: Ken Matsui <kmat...@gcc.gnu.org>
Reviewed-by: Patrick Palka <ppa...@redhat.com>
Reviewed-by: Jonathan Wakely <jwak...@redhat.com>
Diff:
---
libstdc++-v3/include/bits/cpp_type_traits.h | 8 ++++++
libstdc++-v3/include/std/type_traits | 44 +++++++++++++++++++++++------
2 files changed, 44 insertions(+), 8 deletions(-)
diff --git a/libstdc++-v3/include/bits/cpp_type_traits.h
b/libstdc++-v3/include/bits/cpp_type_traits.h
index 59f1a1875eb8..679eee99b904 100644
--- a/libstdc++-v3/include/bits/cpp_type_traits.h
+++ b/libstdc++-v3/include/bits/cpp_type_traits.h
@@ -363,6 +363,13 @@ __INT_N(__GLIBCXX_TYPE_INT_N_3)
//
// Pointer types
//
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_pointer)
+ template<typename _Tp, bool _IsPtr = __is_pointer(_Tp)>
+ struct __is_pointer : __truth_type<_IsPtr>
+ {
+ enum { __value = _IsPtr };
+ };
+#else
template<typename _Tp>
struct __is_pointer
{
@@ -376,6 +383,7 @@ __INT_N(__GLIBCXX_TYPE_INT_N_3)
enum { __value = 1 };
typedef __true_type __type;
};
+#endif
//
// An arithmetic type is an integer type or a floating point type
diff --git a/libstdc++-v3/include/std/type_traits
b/libstdc++-v3/include/std/type_traits
index 8c8219b2697c..0ef112926575 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -542,19 +542,33 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
: public true_type { };
#endif
- template<typename>
- struct __is_pointer_helper
+ /// is_pointer
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_pointer)
+ template<typename _Tp>
+ struct is_pointer
+ : public __bool_constant<__is_pointer(_Tp)>
+ { };
+#else
+ template<typename _Tp>
+ struct is_pointer
: public false_type { };
template<typename _Tp>
- struct __is_pointer_helper<_Tp*>
+ struct is_pointer<_Tp*>
: public true_type { };
- /// is_pointer
template<typename _Tp>
- struct is_pointer
- : public __is_pointer_helper<__remove_cv_t<_Tp>>::type
- { };
+ struct is_pointer<_Tp* const>
+ : public true_type { };
+
+ template<typename _Tp>
+ struct is_pointer<_Tp* volatile>
+ : public true_type { };
+
+ template<typename _Tp>
+ struct is_pointer<_Tp* const volatile>
+ : public true_type { };
+#endif
/// is_lvalue_reference
template<typename>
@@ -3306,8 +3320,22 @@ template <typename _Tp, size_t _Num>
inline constexpr bool is_array_v<_Tp[_Num]> = true;
#endif
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_pointer)
+template <typename _Tp>
+ inline constexpr bool is_pointer_v = __is_pointer(_Tp);
+#else
template <typename _Tp>
- inline constexpr bool is_pointer_v = is_pointer<_Tp>::value;
+ inline constexpr bool is_pointer_v = false;
+template <typename _Tp>
+ inline constexpr bool is_pointer_v<_Tp*> = true;
+template <typename _Tp>
+ inline constexpr bool is_pointer_v<_Tp* const> = true;
+template <typename _Tp>
+ inline constexpr bool is_pointer_v<_Tp* volatile> = true;
+template <typename _Tp>
+ inline constexpr bool is_pointer_v<_Tp* const volatile> = true;
+#endif
+
template <typename _Tp>
inline constexpr bool is_lvalue_reference_v = false;
template <typename _Tp>
