[PATCH 0/2] Optimize is_member_pointer trait performance

[PATCH 0/2] Optimize is_member_pointer trait performance

[Ken Matsui]

This patch series optimizes is_member_pointer trait
performance. The first patch implements __is_member_pointer
built-in trait. The second patch optimizes is_member_pointer
trait performance by using __is_member_pointer built-in trait
if available.

The performance improvement is shown in the following benchmark:

https://github.com/ken-matsui/gsoc23/blob/main/is_member_pointer_v.md#mon-sep-11-092927-pm-pdt-2023

Time: -47.2037% +/- 2.12936%
Peak Memory Usage: -39.4183% +/- 0.00217276%
Total Memory Usage: -41.9905% +/- 0%

Ken Matsui (2):
  c++: Implement __is_member_pointer built-in trait
  libstdc++: Optimize is_member_pointer trait performance

 gcc/cp/constraint.cc                         |  3 ++
 gcc/cp/cp-trait.def                          |  1 +
 gcc/cp/semantics.cc                          |  4 +++
 gcc/testsuite/g++.dg/ext/has-builtin-1.C     |  3 ++
 gcc/testsuite/g++.dg/ext/is_member_pointer.C | 30 ++++++++++++++++++++
 libstdc++-v3/include/std/type_traits         | 16 ++++++++++-
 6 files changed, 56 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/ext/is_member_pointer.C

-- 
2.42.0

[PATCH 1/2] c++: Implement __is_member_pointer built-in trait

[Ken Matsui]

This patch implements built-in trait for std::is_member_pointer.

gcc/cp/ChangeLog:

	* cp-trait.def (IS_MEMBER_POINTER): Define __is_member_pointer.
	* constraint.cc (diagnose_trait_expr): Handle CPTK_IS_MEMBER_POINTER.
	* semantics.cc (trait_expr_value): Likewise.
	(finish_trait_expr): Likewise.

gcc/testsuite/ChangeLog:

	* g++.dg/ext/has-builtin-1.C: Test existence of __is_member_pointer.
	* g++.dg/ext/is_member_pointer.C: New test.

Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
---
 gcc/cp/constraint.cc                         |  3 ++
 gcc/cp/cp-trait.def                          |  1 +
 gcc/cp/semantics.cc                          |  4 +++
 gcc/testsuite/g++.dg/ext/has-builtin-1.C     |  3 ++
 gcc/testsuite/g++.dg/ext/is_member_pointer.C | 30 ++++++++++++++++++++
 5 files changed, 41 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/ext/is_member_pointer.C

diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
index c9e4e7043cd..a3e90281d29 100644
--- a/gcc/cp/constraint.cc
+++ b/gcc/cp/constraint.cc
@@ -3757,6 +3757,9 @@ diagnose_trait_expr (tree expr, tree args)
     case CPTK_IS_TRIVIALLY_COPYABLE:
       inform (loc, "  %qT is not trivially copyable", t1);
       break;
+    case CPTK_IS_MEMBER_POINTER:
+      inform (loc, "  %qT is not a member pointer", t1);
+      break;
     case CPTK_IS_ASSIGNABLE:
       inform (loc, "  %qT is not assignable from %qT", t1, t2);
       break;
diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
index 8b7fece0cc8..9aa11eb4280 100644
--- a/gcc/cp/cp-trait.def
+++ b/gcc/cp/cp-trait.def
@@ -69,6 +69,7 @@ DEFTRAIT_EXPR (IS_ENUM, "__is_enum", 1)
 DEFTRAIT_EXPR (IS_FINAL, "__is_final", 1)
 DEFTRAIT_EXPR (IS_LAYOUT_COMPATIBLE, "__is_layout_compatible", 2)
 DEFTRAIT_EXPR (IS_LITERAL_TYPE, "__is_literal_type", 1)
+DEFTRAIT_EXPR (IS_MEMBER_POINTER, "__is_member_pointer", 1)
 DEFTRAIT_EXPR (IS_NOTHROW_ASSIGNABLE, "__is_nothrow_assignable", 2)
 DEFTRAIT_EXPR (IS_NOTHROW_CONSTRUCTIBLE, "__is_nothrow_constructible", -1)
 DEFTRAIT_EXPR (IS_NOTHROW_CONVERTIBLE, "__is_nothrow_convertible", 2)
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 0f7f4e87ae4..7b4ffb283f1 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -12169,6 +12169,9 @@ trait_expr_value (cp_trait_kind kind, tree type1, tree type2)
     case CPTK_IS_TRIVIAL:
       return trivial_type_p (type1);
 
+    case CPTK_IS_MEMBER_POINTER:
+      return TYPE_PTRMEM_P (type1);
+
     case CPTK_IS_TRIVIALLY_ASSIGNABLE:
       return is_trivially_xible (MODIFY_EXPR, type1, type2);
 
@@ -12359,6 +12362,7 @@ finish_trait_expr (location_t loc, cp_trait_kind kind, tree type1, tree type2)
     case CPTK_IS_ENUM:
     case CPTK_IS_UNION:
     case CPTK_IS_SAME:
+    case CPTK_IS_MEMBER_POINTER:
       break;
 
     case CPTK_IS_LAYOUT_COMPATIBLE:
diff --git a/gcc/testsuite/g++.dg/ext/has-builtin-1.C b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
index f343e153e56..31cbc43a26f 100644
--- a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
+++ b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
@@ -146,3 +146,6 @@
 #if !__has_builtin (__remove_cvref)
 # error "__has_builtin (__remove_cvref) failed"
 #endif
+#if !__has_builtin (__is_member_pointer)
+# error "__has_builtin (__is_member_pointer) failed"
+#endif
diff --git a/gcc/testsuite/g++.dg/ext/is_member_pointer.C b/gcc/testsuite/g++.dg/ext/is_member_pointer.C
new file mode 100644
index 00000000000..7ee2e3ab90c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/is_member_pointer.C
@@ -0,0 +1,30 @@
+// { dg-do compile { target c++11 } }
+
+#include <testsuite_tr1.h>
+
+using namespace __gnu_test;
+
+#define SA(X) static_assert((X),#X)
+
+#define SA_TEST_NON_VOLATILE(TRAIT, TYPE, EXPECT)	\
+  SA(TRAIT(TYPE) == EXPECT);						\
+  SA(TRAIT(const TYPE) == EXPECT)
+
+#define SA_TEST_CATEGORY(TRAIT, TYPE, EXPECT)	\
+  SA(TRAIT(TYPE) == EXPECT);					\
+  SA(TRAIT(const TYPE) == EXPECT);				\
+  SA(TRAIT(volatile TYPE) == EXPECT);			\
+  SA(TRAIT(const volatile TYPE) == EXPECT)
+
+SA_TEST_CATEGORY(__is_member_pointer, int (ClassType::*), true);
+SA_TEST_CATEGORY(__is_member_pointer, ClassType (ClassType::*), true);
+
+SA_TEST_NON_VOLATILE(__is_member_pointer, int (ClassType::*)(int), true);
+SA_TEST_NON_VOLATILE(__is_member_pointer, int (ClassType::*)(int) const, true);
+SA_TEST_NON_VOLATILE(__is_member_pointer, int (ClassType::*)(float, ...), true);
+SA_TEST_NON_VOLATILE(__is_member_pointer, ClassType (ClassType::*)(ClassType), true);
+SA_TEST_NON_VOLATILE(__is_member_pointer,
+        float (ClassType::*)(int, float, int[], int&), true);
+
+// Sanity check.
+SA_TEST_CATEGORY(__is_member_pointer, ClassType, false);
-- 
2.42.0

[PATCH 2/2] libstdc++: Optimize is_member_pointer trait performance

[Ken Matsui]

This patch optimizes the performance of the is_member_pointer trait
by dispatching to the new __is_member_pointer built-in trait.

libstdc++-v3/ChangeLog:

	* include/std/type_traits (is_member_pointer): Use __is_member_pointer
	built-in trait.
	(is_member_pointer_v): Likewise.

Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
---
 libstdc++-v3/include/std/type_traits | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
index 677cd934b94..69dccfa035d 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -709,6 +709,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     struct is_compound
     : public __not_<is_fundamental<_Tp>>::type { };
 
+  /// is_member_pointer
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_member_pointer)
+  template<typename _Tp>
+    struct is_member_pointer
+    : public __bool_constant<__is_member_pointer(_Tp)>
+    { };
+#else
   /// @cond undocumented
   template<typename _Tp>
     struct __is_member_pointer_helper
@@ -719,11 +726,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     : public true_type { };
   /// @endcond
 
-  /// is_member_pointer
   template<typename _Tp>
     struct is_member_pointer
     : public __is_member_pointer_helper<__remove_cv_t<_Tp>>::type
     { };
+#endif
 
   template<typename, typename>
     struct is_same;
@@ -3216,8 +3223,15 @@ template <typename _Tp>
   inline constexpr bool is_scalar_v = is_scalar<_Tp>::value;
 template <typename _Tp>
   inline constexpr bool is_compound_v = is_compound<_Tp>::value;
+
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_member_pointer)
+template <typename _Tp>
+  inline constexpr bool is_member_pointer_v = __is_member_pointer(_Tp);
+#else
 template <typename _Tp>
   inline constexpr bool is_member_pointer_v = is_member_pointer<_Tp>::value;
+#endif
+
 template <typename _Tp>
   inline constexpr bool is_const_v = false;
 template <typename _Tp>
-- 
2.42.0