[PATCH 0/2] Optimize is_member_function_pointer trait performance

[PATCH 0/2] Optimize is_member_function_pointer trait performance

[Ken Matsui]

This patch series optimizes is_member_function_pointer trait
performance. The first patch implements __is_member_function_pointer
built-in trait. The second patch optimizes is_member_function_pointer
trait performance by using __is_member_function_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_function_pointer_v.md#mon-sep-11-095601-am-pdt-2023

Time: -35.1125%
Peak Memory Usage: -25.783%
Total Memory Usage: -27.9437%

Sincerely,
Ken Matsui

Ken Matsui (2):
  c++: Implement __is_member_function_pointer built-in trait
  libstdc++: Optimize is_member_function_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 ++
 .../g++.dg/ext/is_member_function_pointer.C   | 31 +++++++++++++++++++
 libstdc++-v3/include/std/type_traits          | 16 ++++++++++
 6 files changed, 58 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/ext/is_member_function_pointer.C

-- 
2.42.0

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

[Ken Matsui]

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

gcc/cp/ChangeLog:

	* cp-trait.def (IS_MEMBER_FUNCTION_POINTER): Define
	__is_member_function_pointer.
	* constraint.cc (diagnose_trait_expr): Handle
	CPTK_IS_MEMBER_FUNCTION_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_function_pointer.
	* g++.dg/ext/is_member_function_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 ++
 .../g++.dg/ext/is_member_function_pointer.C   | 31 +++++++++++++++++++
 5 files changed, 42 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/ext/is_member_function_pointer.C

diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
index c9e4e7043cd..e366095c47e 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_FUNCTION_POINTER:
+      inform (loc, "  %qT is not a member function 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..47e6f3d5541 100644
--- a/gcc/cp/cp-trait.def
+++ b/gcc/cp/cp-trait.def
@@ -72,6 +72,7 @@ DEFTRAIT_EXPR (IS_LITERAL_TYPE, "__is_literal_type", 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)
+DEFTRAIT_EXPR (IS_MEMBER_FUNCTION_POINTER, "__is_member_function_pointer", 1)
 DEFTRAIT_EXPR (IS_POINTER_INTERCONVERTIBLE_BASE_OF, "__is_pointer_interconvertible_base_of", 2)
 DEFTRAIT_EXPR (IS_POD, "__is_pod", 1)
 DEFTRAIT_EXPR (IS_POLYMORPHIC, "__is_polymorphic", 1)
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 0f7f4e87ae4..d47db9a70aa 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -12193,6 +12193,9 @@ trait_expr_value (cp_trait_kind kind, tree type1, tree type2)
     case CPTK_IS_NOTHROW_CONSTRUCTIBLE:
       return is_nothrow_xible (INIT_EXPR, type1, type2);
 
+    case CPTK_IS_MEMBER_FUNCTION_POINTER:
+      return TYPE_PTRMEMFUNC_P (type1);
+
     case CPTK_IS_CONVERTIBLE:
       return is_convertible (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_FUNCTION_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..2385a475344 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_function_pointer)
+# error "__has_builtin (__is_member_function_pointer) failed"
+#endif
diff --git a/gcc/testsuite/g++.dg/ext/is_member_function_pointer.C b/gcc/testsuite/g++.dg/ext/is_member_function_pointer.C
new file mode 100644
index 00000000000..555123e8f07
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/is_member_function_pointer.C
@@ -0,0 +1,31 @@
+// { dg-do compile { target c++11 } }
+
+#include <testsuite_tr1.h>
+
+using namespace __gnu_test;
+
+#define SA(X) static_assert((X),#X)
+
+#define SA_TEST_FN(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)
+
+// Positive tests.
+SA_TEST_FN(__is_member_function_pointer, int (ClassType::*) (int), true);
+SA_TEST_FN(__is_member_function_pointer, int (ClassType::*) (int) const, true);
+SA_TEST_FN(__is_member_function_pointer, int (ClassType::*) (float, ...), true);
+SA_TEST_FN(__is_member_function_pointer, ClassType (ClassType::*) (ClassType), true);
+SA_TEST_FN(__is_member_function_pointer, float (ClassType::*) (int, float, int[], int&), true);
+
+// Negative tests.
+SA_TEST_CATEGORY(__is_member_function_pointer, int (ClassType::*), false);
+SA_TEST_CATEGORY(__is_member_function_pointer, ClassType (ClassType::*), false);
+
+// Sanity check.
+SA_TEST_CATEGORY(__is_member_function_pointer, ClassType, false);
-- 
2.42.0

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

[Ken Matsui]

This patch optimizes the performance of the is_member_function_pointer trait
by dispatching to the new __is_member_function_pointer built-in trait.

libstdc++-v3/ChangeLog:

	* include/std/type_traits (is_member_function_pointer): Use
	__is_member_function_pointer built-in trait.
	(is_member_function_pointer_v): Likewise.

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

diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
index 677cd934b94..98aeb104653 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -581,6 +581,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     : public __is_member_object_pointer_helper<__remove_cv_t<_Tp>>::type
     { };
 
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_member_function_pointer)
+  /// is_member_function_pointer
+  template<typename _Tp>
+    struct is_member_function_pointer
+    : public __bool_constant<__is_member_function_pointer(_Tp)>
+    { };
+#else
   template<typename>
     struct __is_member_function_pointer_helper
     : public false_type { };
@@ -594,6 +601,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
     struct is_member_function_pointer
     : public __is_member_function_pointer_helper<__remove_cv_t<_Tp>>::type
     { };
+#endif
 
   /// is_enum
   template<typename _Tp>
@@ -3189,9 +3197,17 @@ template <typename _Tp>
 template <typename _Tp>
   inline constexpr bool is_member_object_pointer_v =
     is_member_object_pointer<_Tp>::value;
+
+#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_member_function_pointer)
+template <typename _Tp>
+  inline constexpr bool is_member_function_pointer_v =
+    __is_member_function_pointer(_Tp);
+#else
 template <typename _Tp>
   inline constexpr bool is_member_function_pointer_v =
     is_member_function_pointer<_Tp>::value;
+#endif
+
 template <typename _Tp>
   inline constexpr bool is_enum_v = __is_enum(_Tp);
 template <typename _Tp>
-- 
2.42.0