Re: [PATCH v3 1/3] c++, libstdc++: Implement __is_arithmetic built-in trait

["François Dumont" <frs.dumont@gmail.com>]

On 18/07/2023 08:27, Ken Matsui via Libstdc++ wrote:
> This patch implements built-in trait for std::is_arithmetic.
>
> gcc/cp/ChangeLog:
>
> 	* cp-trait.def: Define __is_arithmetic.
> 	* constraint.cc (diagnose_trait_expr): Handle CPTK_IS_ARITHMETIC.
> 	* semantics.cc (trait_expr_value): Likewise.
> 	(finish_trait_expr): Likewise.
>
> gcc/testsuite/ChangeLog:
>
> 	* g++.dg/ext/has-builtin-1.C: Test existence of __is_arithmetic.
> 	* g++.dg/ext/is_arithmetic.C: New test.
> 	* g++.dg/tm/pr46567.C (__is_arithmetic): Rename to ...
> 	(__is_arith): ... this.
> 	* g++.dg/torture/pr57107.C: Likewise.
>
> libstdc++-v3/ChangeLog:
>
> 	* include/bits/cpp_type_traits.h (__is_arithmetic): Rename to ...
> 	(__is_arith): ... this.
> 	* include/c_global/cmath: Use __is_arith instead.
> 	* include/c_std/cmath: Likewise.
> 	* include/tr1/cmath: 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_arithmetic.C    | 33 ++++++++++++++
>   gcc/testsuite/g++.dg/tm/pr46567.C           |  6 +--
>   gcc/testsuite/g++.dg/torture/pr57107.C      |  4 +-
>   libstdc++-v3/include/bits/cpp_type_traits.h |  4 +-
>   libstdc++-v3/include/c_global/cmath         | 48 ++++++++++-----------
>   libstdc++-v3/include/c_std/cmath            | 24 +++++------
>   libstdc++-v3/include/tr1/cmath              | 24 +++++------
>   11 files changed, 99 insertions(+), 55 deletions(-)
>   create mode 100644 gcc/testsuite/g++.dg/ext/is_arithmetic.C
>
> diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
> index 8cf0f2d0974..bd517d08843 100644
> --- a/gcc/cp/constraint.cc
> +++ b/gcc/cp/constraint.cc
> @@ -3754,6 +3754,9 @@ diagnose_trait_expr (tree expr, tree args)
>       case CPTK_IS_AGGREGATE:
>         inform (loc, "  %qT is not an aggregate", t1);
>         break;
> +    case CPTK_IS_ARITHMETIC:
> +      inform (loc, "  %qT is not an arithmetic type", t1);
> +      break;
>       case CPTK_IS_TRIVIALLY_COPYABLE:
>         inform (loc, "  %qT is not trivially copyable", t1);
>         break;
> diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
> index 8b7fece0cc8..a95aeeaf778 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_ARITHMETIC, "__is_arithmetic", 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..4531f047d73 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_ARITHMETIC:
> +      return ARITHMETIC_TYPE_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_ARITHMETIC:
>         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..3d63b0101d1 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_arithmetic)
> +# error "__has_builtin (__is_arithmetic) failed"
> +#endif
> diff --git a/gcc/testsuite/g++.dg/ext/is_arithmetic.C b/gcc/testsuite/g++.dg/ext/is_arithmetic.C
> new file mode 100644
> index 00000000000..fd35831f646
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/ext/is_arithmetic.C
> @@ -0,0 +1,33 @@
> +// { dg-do compile { target c++11 } }
> +
> +#include <testsuite_tr1.h>
> +
> +using namespace __gnu_test;
> +
> +#define SA(X) static_assert((X),#X)
> +#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_arithmetic, void, false);
> +
> +SA_TEST_CATEGORY(__is_arithmetic, char, true);
> +SA_TEST_CATEGORY(__is_arithmetic, signed char, true);
> +SA_TEST_CATEGORY(__is_arithmetic, unsigned char, true);
> +SA_TEST_CATEGORY(__is_arithmetic, wchar_t, true);
> +SA_TEST_CATEGORY(__is_arithmetic, short, true);
> +SA_TEST_CATEGORY(__is_arithmetic, unsigned short, true);
> +SA_TEST_CATEGORY(__is_arithmetic, int, true);
> +SA_TEST_CATEGORY(__is_arithmetic, unsigned int, true);
> +SA_TEST_CATEGORY(__is_arithmetic, long, true);
> +SA_TEST_CATEGORY(__is_arithmetic, unsigned long, true);
> +SA_TEST_CATEGORY(__is_arithmetic, long long, true);
> +SA_TEST_CATEGORY(__is_arithmetic, unsigned long long, true);
> +SA_TEST_CATEGORY(__is_arithmetic, float, true);
> +SA_TEST_CATEGORY(__is_arithmetic, double, true);
> +SA_TEST_CATEGORY(__is_arithmetic, long double, true);
> +
> +// Sanity check.
> +SA_TEST_CATEGORY(__is_arithmetic, ClassType, false);
> diff --git a/gcc/testsuite/g++.dg/tm/pr46567.C b/gcc/testsuite/g++.dg/tm/pr46567.C
> index 6d791484448..8d2d3eb6c5a 100644
> --- a/gcc/testsuite/g++.dg/tm/pr46567.C
> +++ b/gcc/testsuite/g++.dg/tm/pr46567.C
> @@ -217,16 +217,16 @@ namespace std __attribute__ ((__visibility__ ("default"))) {
>         typedef __true_type __type;
>       };
>     template<typename _Tp>
> -    struct __is_arithmetic
> +    struct __is_arith
>       : public __traitor<__is_integer<_Tp>, __is_floating<_Tp> >
>       { };
>     template<typename _Tp>
>       struct __is_fundamental
> -    : public __traitor<__is_void<_Tp>, __is_arithmetic<_Tp> >
> +    : public __traitor<__is_void<_Tp>, __is_arith<_Tp> >
>       { };
>     template<typename _Tp>
>       struct __is_scalar
> -    : public __traitor<__is_arithmetic<_Tp>, __is_pointer<_Tp> >
> +    : public __traitor<__is_arith<_Tp>, __is_pointer<_Tp> >
>       { };
>     template<typename _Tp>
>       struct __is_char
> diff --git a/gcc/testsuite/g++.dg/torture/pr57107.C b/gcc/testsuite/g++.dg/torture/pr57107.C
> index 4dbd32bd298..ecbe99db4f8 100644
> --- a/gcc/testsuite/g++.dg/torture/pr57107.C
> +++ b/gcc/testsuite/g++.dg/torture/pr57107.C
> @@ -25,9 +25,9 @@ namespace std __attribute__ ((__visibility__ ("default"))) {
>   	enum {
>   	    __value = 0 };
>       };
> -    template<typename _Tp>     struct __is_arithmetic     : public __traitor<__is_integer<_Tp>, __is_floating<_Tp> >     {
> +    template<typename _Tp>     struct __is_arith     : 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_arith<_Tp>, __is_pointer<_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..d00d1ea8d75 100644
> --- a/libstdc++-v3/include/bits/cpp_type_traits.h
> +++ b/libstdc++-v3/include/bits/cpp_type_traits.h
> @@ -381,7 +381,7 @@ __INT_N(__GLIBCXX_TYPE_INT_N_3)
>     // An arithmetic type is an integer type or a floating point type
>     //
>     template<typename _Tp>
> -    struct __is_arithmetic
> +    struct __is_arith
>       : public __traitor<__is_integer<_Tp>, __is_floating<_Tp> >
>       { };

'ptr' is a well known alias of 'pointer', I wouldn't say the same for 
'arith' and 'arithmetic'.

But wait for a native-english feedback to change anything.