Re: [PATCH v3 1/2] c++, libstdc++: Implement __is_pointer built-in trait

[Ken Matsui <kmatsui@cs.washington.edu>]

Hi,

Here is the updated benchmark result for is_pointer:

https://github.com/ken-matsui/gcc-benches/blob/main/is_pointer.md#wed-jul-12-055654-pm-pdt-2023

Time: -2.79488%
Peak Memory Usage: -2.39379%
Total Memory Usage: -3.39559%

Sincerely,
Ken Matsui

On Wed, Jul 12, 2023 at 6:12 PM Ken Matsui <kmatsui@gcc.gnu.org> wrote:
>
> This patch implements built-in trait for std::is_pointer.
>
> gcc/cp/ChangeLog:
>
>         * cp-trait.def: Define __is_pointer.
>         * constraint.cc (diagnose_trait_expr): Handle CPTK_IS_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_pointer.
>         * g++.dg/ext/is_pointer.C: New test.
>         * g++.dg/tm/pr46567.C (__is_pointer): Rename to ...
>         (__is_ptr): ... this.
>         * g++.dg/torture/20070621-1.C: Likewise.
>         * g++.dg/torture/pr57107.C: Likewise.
>
> libstdc++-v3/ChangeLog:
>
>         * include/bits/cpp_type_traits.h (__is_pointer): Rename to ...
>         (__is_ptr): ... this.
>         * include/bits/deque.tcc: Use __is_ptr instead.
>         * include/bits/stl_algobase.h: Likewise.
>
> 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_pointer.C       | 51 +++++++++++++++++++++
>  gcc/testsuite/g++.dg/tm/pr46567.C           | 22 ++++-----
>  gcc/testsuite/g++.dg/torture/20070621-1.C   |  4 +-
>  gcc/testsuite/g++.dg/torture/pr57107.C      |  4 +-
>  libstdc++-v3/include/bits/cpp_type_traits.h |  6 +--
>  libstdc++-v3/include/bits/deque.tcc         |  6 +--
>  libstdc++-v3/include/bits/stl_algobase.h    |  6 +--
>  11 files changed, 86 insertions(+), 24 deletions(-)
>  create mode 100644 gcc/testsuite/g++.dg/ext/is_pointer.C
>
> diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
> index 8cf0f2d0974..30266204eb5 100644
> --- a/gcc/cp/constraint.cc
> +++ b/gcc/cp/constraint.cc
> @@ -3751,6 +3751,9 @@ diagnose_trait_expr (tree expr, tree args)
>      case CPTK_IS_UNION:
>        inform (loc, "  %qT is not a union", t1);
>        break;
> +    case CPTK_IS_POINTER:
> +      inform (loc, "  %qT is not a pointer", t1);
> +      break;
>      case CPTK_IS_AGGREGATE:
>        inform (loc, "  %qT is not an aggregate", t1);
>        break;
> diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
> index 8b7fece0cc8..b7c263e9a77 100644
> --- a/gcc/cp/cp-trait.def
> +++ b/gcc/cp/cp-trait.def
> @@ -82,6 +82,7 @@ DEFTRAIT_EXPR (IS_TRIVIALLY_ASSIGNABLE, "__is_trivially_assignable", 2)
>  DEFTRAIT_EXPR (IS_TRIVIALLY_CONSTRUCTIBLE, "__is_trivially_constructible", -1)
>  DEFTRAIT_EXPR (IS_TRIVIALLY_COPYABLE, "__is_trivially_copyable", 1)
>  DEFTRAIT_EXPR (IS_UNION, "__is_union", 1)
> +DEFTRAIT_EXPR (IS_POINTER, "__is_pointer", 1)
>  DEFTRAIT_EXPR (REF_CONSTRUCTS_FROM_TEMPORARY, "__reference_constructs_from_temporary", 2)
>  DEFTRAIT_EXPR (REF_CONVERTS_FROM_TEMPORARY, "__reference_converts_from_temporary", 2)
>  /* FIXME Added space to avoid direct usage in GCC 13.  */
> diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
> index 8fb47fd179e..68f8a4fe85b 100644
> --- a/gcc/cp/semantics.cc
> +++ b/gcc/cp/semantics.cc
> @@ -12118,6 +12118,9 @@ trait_expr_value (cp_trait_kind kind, tree type1, tree type2)
>      case CPTK_IS_UNION:
>        return type_code1 == UNION_TYPE;
>
> +    case CPTK_IS_POINTER:
> +      return TYPE_PTR_P (type1);
> +
>      case CPTK_IS_ASSIGNABLE:
>        return is_xible (MODIFY_EXPR, type1, type2);
>
> @@ -12296,6 +12299,7 @@ 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_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..9dace5cbd48 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_pointer)
> +# error "__has_builtin (__is_pointer) failed"
> +#endif
> diff --git a/gcc/testsuite/g++.dg/ext/is_pointer.C b/gcc/testsuite/g++.dg/ext/is_pointer.C
> new file mode 100644
> index 00000000000..d6e39565950
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/ext/is_pointer.C
> @@ -0,0 +1,51 @@
> +// { dg-do compile { target c++11 } }
> +
> +#define SA(X) static_assert((X),#X)
> +
> +SA(!__is_pointer(int));
> +SA(__is_pointer(int*));
> +SA(__is_pointer(int**));
> +
> +SA(__is_pointer(const int*));
> +SA(__is_pointer(const int**));
> +SA(__is_pointer(int* const));
> +SA(__is_pointer(int** const));
> +SA(__is_pointer(int* const* const));
> +
> +SA(__is_pointer(volatile int*));
> +SA(__is_pointer(volatile int**));
> +SA(__is_pointer(int* volatile));
> +SA(__is_pointer(int** volatile));
> +SA(__is_pointer(int* volatile* volatile));
> +
> +SA(__is_pointer(const volatile int*));
> +SA(__is_pointer(const volatile int**));
> +SA(__is_pointer(const int* volatile));
> +SA(__is_pointer(volatile int* const));
> +SA(__is_pointer(int* const volatile));
> +SA(__is_pointer(const int** volatile));
> +SA(__is_pointer(volatile int** const));
> +SA(__is_pointer(int** const volatile));
> +SA(__is_pointer(int* const* const volatile));
> +SA(__is_pointer(int* volatile* const volatile));
> +SA(__is_pointer(int* const volatile* const volatile));
> +
> +SA(!__is_pointer(int&));
> +SA(!__is_pointer(const int&));
> +SA(!__is_pointer(volatile int&));
> +SA(!__is_pointer(const volatile int&));
> +
> +SA(!__is_pointer(int&&));
> +SA(!__is_pointer(const int&&));
> +SA(!__is_pointer(volatile int&&));
> +SA(!__is_pointer(const volatile int&&));
> +
> +SA(!__is_pointer(int[3]));
> +SA(!__is_pointer(const int[3]));
> +SA(!__is_pointer(volatile int[3]));
> +SA(!__is_pointer(const volatile int[3]));
> +
> +SA(!__is_pointer(int(int)));
> +SA(__is_pointer(int(*const)(int)));
> +SA(__is_pointer(int(*volatile)(int)));
> +SA(__is_pointer(int(*const volatile)(int)));
> diff --git a/gcc/testsuite/g++.dg/tm/pr46567.C b/gcc/testsuite/g++.dg/tm/pr46567.C
> index 6d791484448..f08bbf6fd7b 100644
> --- a/gcc/testsuite/g++.dg/tm/pr46567.C
> +++ b/gcc/testsuite/g++.dg/tm/pr46567.C
> @@ -192,13 +192,13 @@ namespace std __attribute__ ((__visibility__ ("default"))) {
>        typedef __true_type __type;
>      };
>    template<typename _Tp>
> -    struct __is_pointer
> +    struct __is_ptr
>      {
>        enum { __value = 0 };
>        typedef __false_type __type;
>      };
>    template<typename _Tp>
> -    struct __is_pointer<_Tp*>
> +    struct __is_ptr<_Tp*>
>      {
>        enum { __value = 1 };
>        typedef __true_type __type;
> @@ -226,7 +226,7 @@ namespace std __attribute__ ((__visibility__ ("default"))) {
>      { };
>    template<typename _Tp>
>      struct __is_scalar
> -    : public __traitor<__is_arithmetic<_Tp>, __is_pointer<_Tp> >
> +    : public __traitor<__is_arithmetic<_Tp>, __is_ptr<_Tp> >
>      { };
>    template<typename _Tp>
>      struct __is_char
> @@ -1202,8 +1202,8 @@ namespace std __attribute__ ((__visibility__ ("default"))) {
>        typedef typename iterator_traits<_OI>::value_type _ValueTypeO;
>        typedef typename iterator_traits<_II>::iterator_category _Category;
>        const bool __simple = (__is_pod(_ValueTypeI)
> -                     && __is_pointer<_II>::__value
> -                     && __is_pointer<_OI>::__value
> +                     && __is_ptr<_II>::__value
> +                     && __is_ptr<_OI>::__value
>         && __are_same<_ValueTypeI, _ValueTypeO>::__value);
>        return std::__copy_move<_IsMove, __simple,
>                        _Category>::__copy_m(__first, __last, __result);
> @@ -1294,8 +1294,8 @@ namespace std __attribute__ ((__visibility__ ("default"))) {
>        typedef typename iterator_traits<_BI2>::value_type _ValueType2;
>        typedef typename iterator_traits<_BI1>::iterator_category _Category;
>        const bool __simple = (__is_pod(_ValueType1)
> -                     && __is_pointer<_BI1>::__value
> -                     && __is_pointer<_BI2>::__value
> +                     && __is_ptr<_BI1>::__value
> +                     && __is_ptr<_BI2>::__value
>         && __are_same<_ValueType1, _ValueType2>::__value);
>        return std::__copy_move_backward<_IsMove, __simple,
>                                 _Category>::__copy_move_b(__first,
> @@ -1426,8 +1426,8 @@ namespace std __attribute__ ((__visibility__ ("default"))) {
>        typedef typename iterator_traits<_II1>::value_type _ValueType1;
>        typedef typename iterator_traits<_II2>::value_type _ValueType2;
>        const bool __simple = (__is_integer<_ValueType1>::__value
> -                     && __is_pointer<_II1>::__value
> -                     && __is_pointer<_II2>::__value
> +                     && __is_ptr<_II1>::__value
> +                     && __is_ptr<_II2>::__value
>         && __are_same<_ValueType1, _ValueType2>::__value);
>        return std::__equal<__simple>::equal(__first1, __last1, __first2);
>      }
> @@ -1515,8 +1515,8 @@ namespace std __attribute__ ((__visibility__ ("default"))) {
>   (__is_byte<_ValueType1>::__value && __is_byte<_ValueType2>::__value
>    && !__gnu_cxx::__numeric_traits<_ValueType1>::__is_signed
>    && !__gnu_cxx::__numeric_traits<_ValueType2>::__is_signed
> -  && __is_pointer<_II1>::__value
> -  && __is_pointer<_II2>::__value);
> +  && __is_ptr<_II1>::__value
> +  && __is_ptr<_II2>::__value);
>        return std::__lexicographical_compare<__simple>::__lc(__first1, __last1,
>            __first2, __last2);
>      }
> diff --git a/gcc/testsuite/g++.dg/torture/20070621-1.C b/gcc/testsuite/g++.dg/torture/20070621-1.C
> index d8a6a76b6b0..b05136163e8 100644
> --- a/gcc/testsuite/g++.dg/torture/20070621-1.C
> +++ b/gcc/testsuite/g++.dg/torture/20070621-1.C
> @@ -18,7 +18,7 @@ namespace std __attribute__ ((__visibility__ ("default"))) {
>          enum {
>    __value = 0 };
>        };
> -    template<typename _Tp>     struct __is_pointer     {
> +    template<typename _Tp>     struct __is_ptr     {
>          enum {
>    __value = 0 };
>        };
> @@ -49,7 +49,7 @@ namespace std __attribute__ ((__visibility__ ("default"))) {
>      template<typename _II1, typename _II2>     inline bool     __equal_aux(_II1 __first1, _II1 __last1, _II2 __first2)     {
>          typedef typename iterator_traits<_II1>::value_type _ValueType1;
>          typedef typename iterator_traits<_II2>::value_type _ValueType2;
> -        const bool __simple = (__is_integer<_ValueType1>::__value                       && __is_pointer<_II1>::__value                       && __is_pointer<_II2>::__value         && __are_same<_ValueType1, _ValueType2>::__value);
> +        const bool __simple = (__is_integer<_ValueType1>::__value                       && __is_ptr<_II1>::__value                       && __is_ptr<_II2>::__value         && __are_same<_ValueType1, _ValueType2>::__value);
>          return std::__equal<__simple>::equal(__first1, __last1, __first2);
>        }
>      template<typename _II1, typename _II2>     inline bool     equal(_II1 __first1, _II1 __last1, _II2 __first2)     {
> diff --git a/gcc/testsuite/g++.dg/torture/pr57107.C b/gcc/testsuite/g++.dg/torture/pr57107.C
> index 4dbd32bd298..be0689096fb 100644
> --- a/gcc/testsuite/g++.dg/torture/pr57107.C
> +++ b/gcc/testsuite/g++.dg/torture/pr57107.C
> @@ -17,7 +17,7 @@ namespace std __attribute__ ((__visibility__ ("default"))) {
>         enum {
>             __value = 0 };
>      };
> -    template<typename _Tp>     struct __is_pointer     {
> +    template<typename _Tp>     struct __is_ptr     {
>         enum {
>             __value = 0 };
>      };
> @@ -27,7 +27,7 @@ namespace std __attribute__ ((__visibility__ ("default"))) {
>      };
>      template<typename _Tp>     struct __is_arithmetic     : public __traitor<__is_integer<_Tp>, __is_floating<_Tp> >     {
>      };
> -    template<typename _Tp>     struct __is_scalar     : public __traitor<__is_arithmetic<_Tp>, __is_pointer<_Tp> >     {
> +    template<typename _Tp>     struct __is_scalar     : public __traitor<__is_arithmetic<_Tp>, __is_ptr<_Tp> >     {
>      };
>  }
>  namespace __gnu_cxx __attribute__ ((__visibility__ ("default"))) {
> diff --git a/libstdc++-v3/include/bits/cpp_type_traits.h b/libstdc++-v3/include/bits/cpp_type_traits.h
> index 4312f32a4e0..3711e4be526 100644
> --- a/libstdc++-v3/include/bits/cpp_type_traits.h
> +++ b/libstdc++-v3/include/bits/cpp_type_traits.h
> @@ -364,14 +364,14 @@ __INT_N(__GLIBCXX_TYPE_INT_N_3)
>    // Pointer types
>    //
>    template<typename _Tp>
> -    struct __is_pointer
> +    struct __is_ptr
>      {
>        enum { __value = 0 };
>        typedef __false_type __type;
>      };
>
>    template<typename _Tp>
> -    struct __is_pointer<_Tp*>
> +    struct __is_ptr<_Tp*>
>      {
>        enum { __value = 1 };
>        typedef __true_type __type;
> @@ -390,7 +390,7 @@ __INT_N(__GLIBCXX_TYPE_INT_N_3)
>    //
>    template<typename _Tp>
>      struct __is_scalar
> -    : public __traitor<__is_arithmetic<_Tp>, __is_pointer<_Tp> >
> +    : public __traitor<__is_arithmetic<_Tp>, __is_ptr<_Tp> >
>      { };
>
>    //
> diff --git a/libstdc++-v3/include/bits/deque.tcc b/libstdc++-v3/include/bits/deque.tcc
> index a212b8a6940..08d888ee8af 100644
> --- a/libstdc++-v3/include/bits/deque.tcc
> +++ b/libstdc++-v3/include/bits/deque.tcc
> @@ -1273,7 +1273,7 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
>      {
>        const bool __simple =
>         (__is_memcmp_ordered_with<_Tp1, _Tp2>::__value
> -        && __is_pointer<_Ptr>::__value
> +        && __is_ptr<_Ptr>::__value
>  #if __cplusplus > 201703L && __cpp_lib_concepts
>          // For C++20 iterator_traits<volatile T*>::value_type is non-volatile
>          // so __is_byte<T> could be true, but we can't use memcmp with
> @@ -1329,8 +1329,8 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
>      {
>        const bool __simple =
>         (__is_memcmp_ordered_with<_Tp1, _Tp2>::__value
> -        && __is_pointer<_Ptr1>::__value
> -        && __is_pointer<_Ptr2>::__value
> +        && __is_ptr<_Ptr1>::__value
> +        && __is_ptr<_Ptr2>::__value
>  #if __cplusplus > 201703L && __cpp_lib_concepts
>          // For C++20 iterator_traits<volatile T*>::value_type is non-volatile
>          // so __is_byte<T> could be true, but we can't use memcmp with
> diff --git a/libstdc++-v3/include/bits/stl_algobase.h b/libstdc++-v3/include/bits/stl_algobase.h
> index dd95e94f7e9..cf21611fa5c 100644
> --- a/libstdc++-v3/include/bits/stl_algobase.h
> +++ b/libstdc++-v3/include/bits/stl_algobase.h
> @@ -1214,7 +1214,7 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
>      {
>        typedef typename iterator_traits<_II1>::value_type _ValueType1;
>        const bool __simple = ((__is_integer<_ValueType1>::__value
> -                             || __is_pointer<_ValueType1>::__value)
> +                             || __is_ptr<_ValueType1>::__value)
>                              && __memcmpable<_II1, _II2>::__value);
>        return std::__equal<__simple>::equal(__first1, __last1, __first2);
>      }
> @@ -1377,8 +1377,8 @@ _GLIBCXX_END_NAMESPACE_CONTAINER
>        typedef typename iterator_traits<_II2>::value_type _ValueType2;
>        const bool __simple =
>         (__is_memcmp_ordered_with<_ValueType1, _ValueType2>::__value
> -        && __is_pointer<_II1>::__value
> -        && __is_pointer<_II2>::__value
> +        && __is_ptr<_II1>::__value
> +        && __is_ptr<_II2>::__value
>  #if __cplusplus > 201703L && __cpp_lib_concepts
>          // For C++20 iterator_traits<volatile T*>::value_type is non-volatile
>          // so __is_byte<T> could be true, but we can't use memcmp with
> --
> 2.41.0
>