Re: [PATCH v2 1/3] c++, libstdc++: Implement __is_arithmetic built-in trait

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

On Sun, Jul 16, 2023 at 5:28 AM François Dumont <frs.dumont@gmail.com> wrote:
>
>
> On 15/07/2023 06:55, 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_arithmetic): ... this.
> >       * g++.dg/torture/pr57107.C: Likewise.
> >
> > libstdc++-v3/ChangeLog:
> >
> >       * include/bits/cpp_type_traits.h (__is_arithmetic): Rename to ...
> >       (____is_arithmetic): ... this.
> >       * include/c_global/cmath: Use ____is_arithmetic 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..b16f7b685e7 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_arithmetic
> >       : 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_arithmetic<_Tp> >
> >       { };
> >     template<typename _Tp>
> >       struct __is_scalar
> > -    : public __traitor<__is_arithmetic<_Tp>, __is_pointer<_Tp> >
> > +    : public __traitor<____is_arithmetic<_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..4329a6eb4e1 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_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_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..95c55433c81 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_arithmetic
>
> I think Jonathan's remark about avoiding the 4 '_' also applies here.
>
> So rather '__is_arithmetic_type' or even '__is_arithmetic_t'.
>
Oh, thank you for pointing that out! I will fix it.