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From: Jonathan Wakely <jwakely@redhat.com>
To: Ken Matsui <kmatsui@gcc.gnu.org>
Cc: gcc-patches@gcc.gnu.org, libstdc++@gcc.gnu.org
Subject: Re: [PATCH 1/2] c++, libstdc++: implement __is_signed built-in trait
Date: Wed, 12 Jul 2023 11:19:41 +0100	[thread overview]
Message-ID: <CACb0b4m7=E87oKPmZ-WpxAh2WXN70cupL5sjbFWrUePeYwq_qw@mail.gmail.com> (raw)
In-Reply-To: <20230709084717.20744-1-kmatsui@gcc.gnu.org>

On Sun, 9 Jul 2023 at 09:50, Ken Matsui via Libstdc++
<libstdc++@gcc.gnu.org> wrote:
>
> This patch implements built-in trait for std::is_signed.
>
> gcc/cp/ChangeLog:
>
>         * cp-trait.def: Define __is_signed.
>         * constraint.cc (diagnose_trait_expr): Handle CPTK_IS_SIGNED.
>         * semantics.cc (trait_expr_value): Likewise.
>         (finish_trait_expr): Likewise.
>
> gcc/testsuite/ChangeLog:
>
>         * g++.dg/ext/has-builtin-1.C: Test existence of __is_signed.
>         * g++.dg/ext/is_signed.C: New test.
>         * g++.dg/tm/pr46567.C (__is_signed): Rename to ...
>         (____is_signed): ... this.
>
> libstdc++-v3/ChangeLog:
>
>         * include/ext/numeric_traits.h (__is_signed): Rename to ...
>         (____is_signed): ... this.

Again, please do not use four underscores.

This data member of __numeric_traits_integer could be __signed or
__is_signed_integer. I think I prefer __signed here, since the
"integer" part is redundant with __numeric_traits_integer.




>         * include/bits/charconv.h: Use ____is_signed instead.
>         * include/bits/locale_facets.tcc: Likewise.
>         * include/bits/uniform_int_dist.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_signed.C         | 47 ++++++++++++++++++++
>  gcc/testsuite/g++.dg/tm/pr46567.C            | 12 ++---
>  libstdc++-v3/include/bits/charconv.h         |  2 +-
>  libstdc++-v3/include/bits/locale_facets.tcc  |  6 +--
>  libstdc++-v3/include/bits/uniform_int_dist.h |  4 +-
>  libstdc++-v3/include/ext/numeric_traits.h    | 18 ++++----
>  10 files changed, 79 insertions(+), 21 deletions(-)
>  create mode 100644 gcc/testsuite/g++.dg/ext/is_signed.C
>
> diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
> index 8cf0f2d0974..73fcbfe39e8 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_SIGNED:
> +      inform (loc, "  %qT is not a signed type", 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..576d5528d05 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_SIGNED, "__is_signed", 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..17aad992f96 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_SIGNED:
> +      return ARITHMETIC_TYPE_P (type1) && TYPE_SIGN (type1) == SIGNED;
> +
>      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_SIGNED:
>        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..a43202d0d59 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_signed)
> +# error "__has_builtin (__is_signed) failed"
> +#endif
> diff --git a/gcc/testsuite/g++.dg/ext/is_signed.C b/gcc/testsuite/g++.dg/ext/is_signed.C
> new file mode 100644
> index 00000000000..a04b548105d
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/ext/is_signed.C
> @@ -0,0 +1,47 @@
> +// { 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, X, expect) \
> +  SA(TRAIT(X) == expect);                  \
> +  SA(TRAIT(const X) == expect);            \
> +  SA(TRAIT(volatile X) == expect);         \
> +  SA(TRAIT(const volatile X) == expect)
> +
> +SA_TEST_CATEGORY(__is_signed, void, false);
> +
> +SA_TEST_CATEGORY(__is_signed, bool, bool(-1) < bool(0));
> +SA_TEST_CATEGORY(__is_signed, char, char(-1) < char(0));
> +SA_TEST_CATEGORY(__is_signed, signed char, true);
> +SA_TEST_CATEGORY(__is_signed, unsigned char, false);
> +SA_TEST_CATEGORY(__is_signed, wchar_t, wchar_t(-1) < wchar_t(0));
> +SA_TEST_CATEGORY(__is_signed, short, true);
> +SA_TEST_CATEGORY(__is_signed, unsigned short, false);
> +SA_TEST_CATEGORY(__is_signed, int, true);
> +SA_TEST_CATEGORY(__is_signed, unsigned int, false);
> +SA_TEST_CATEGORY(__is_signed, long, true);
> +SA_TEST_CATEGORY(__is_signed, unsigned long, false);
> +SA_TEST_CATEGORY(__is_signed, long long, true);
> +SA_TEST_CATEGORY(__is_signed, unsigned long long, false);
> +
> +SA_TEST_CATEGORY(__is_signed, float, true);
> +SA_TEST_CATEGORY(__is_signed, double, true);
> +SA_TEST_CATEGORY(__is_signed, long double, true);
> +
> +#ifndef __STRICT_ANSI__
> +// GNU Extensions.
> +#ifdef __SIZEOF_INT128__
> +SA_TEST_CATEGORY(__is_signed, __int128, true);
> +SA_TEST_CATEGORY(__is_signed, unsigned __int128, false);
> +#endif
> +
> +#ifdef _GLIBCXX_USE_FLOAT128
> +SA_TEST_CATEGORY(__is_signed, __float128, true);
> +#endif
> +#endif
> +
> +// Sanity check.
> +SA_TEST_CATEGORY(__is_signed, ClassType, false);
> diff --git a/gcc/testsuite/g++.dg/tm/pr46567.C b/gcc/testsuite/g++.dg/tm/pr46567.C
> index 6d791484448..06400fa1178 100644
> --- a/gcc/testsuite/g++.dg/tm/pr46567.C
> +++ b/gcc/testsuite/g++.dg/tm/pr46567.C
> @@ -403,7 +403,7 @@ namespace __gnu_cxx __attribute__ ((__visibility__ ("default"))) {
>      {
>        static const _Value __min = (((_Value)(-1) < 0) ? (_Value)1 << (sizeof(_Value) * 8 - ((_Value)(-1) < 0)) : (_Value)0);
>        static const _Value __max = (((_Value)(-1) < 0) ? (((((_Value)1 << ((sizeof(_Value) * 8 - ((_Value)(-1) < 0)) - 1)) - 1) << 1) + 1) : ~(_Value)0);
> -      static const bool __is_signed = ((_Value)(-1) < 0);
> +      static const bool ____is_signed = ((_Value)(-1) < 0);
>        static const int __digits = (sizeof(_Value) * 8 - ((_Value)(-1) < 0));
>      };
>    template<typename _Value>
> @@ -411,21 +411,21 @@ namespace __gnu_cxx __attribute__ ((__visibility__ ("default"))) {
>    template<typename _Value>
>      const _Value __numeric_traits_integer<_Value>::__max;
>    template<typename _Value>
> -    const bool __numeric_traits_integer<_Value>::__is_signed;
> +    const bool __numeric_traits_integer<_Value>::____is_signed;
>    template<typename _Value>
>      const int __numeric_traits_integer<_Value>::__digits;
>    template<typename _Value>
>      struct __numeric_traits_floating
>      {
>        static const int __max_digits10 = (2 + (std::__are_same<_Value, float>::__value ? 24 : std::__are_same<_Value, double>::__value ? 53 : 64) * 3010 / 10000);
> -      static const bool __is_signed = true;
> +      static const bool ____is_signed = true;
>        static const int __digits10 = (std::__are_same<_Value, float>::__value ? 6 : std::__are_same<_Value, double>::__value ? 15 : 18);
>        static const int __max_exponent10 = (std::__are_same<_Value, float>::__value ? 38 : std::__are_same<_Value, double>::__value ? 308 : 4932);
>      };
>    template<typename _Value>
>      const int __numeric_traits_floating<_Value>::__max_digits10;
>    template<typename _Value>
> -    const bool __numeric_traits_floating<_Value>::__is_signed;
> +    const bool __numeric_traits_floating<_Value>::____is_signed;
>    template<typename _Value>
>      const int __numeric_traits_floating<_Value>::__digits10;
>    template<typename _Value>
> @@ -1513,8 +1513,8 @@ namespace std __attribute__ ((__visibility__ ("default"))) {
>        typedef typename iterator_traits<_II2>::value_type _ValueType2;
>        const bool __simple =
>   (__is_byte<_ValueType1>::__value && __is_byte<_ValueType2>::__value
> -  && !__gnu_cxx::__numeric_traits<_ValueType1>::__is_signed
> -  && !__gnu_cxx::__numeric_traits<_ValueType2>::__is_signed
> +  && !__gnu_cxx::__numeric_traits<_ValueType1>::____is_signed
> +  && !__gnu_cxx::__numeric_traits<_ValueType2>::____is_signed
>    && __is_pointer<_II1>::__value
>    && __is_pointer<_II2>::__value);
>        return std::__lexicographical_compare<__simple>::__lc(__first1, __last1,
> diff --git a/libstdc++-v3/include/bits/charconv.h b/libstdc++-v3/include/bits/charconv.h
> index 20da8303f7a..c6a4c993c17 100644
> --- a/libstdc++-v3/include/bits/charconv.h
> +++ b/libstdc++-v3/include/bits/charconv.h
> @@ -46,7 +46,7 @@ namespace __detail
>    // This accepts 128-bit integers even in strict mode.
>    template<typename _Tp>
>      constexpr bool __integer_to_chars_is_unsigned
> -      = ! __gnu_cxx::__int_traits<_Tp>::__is_signed;
> +      = ! __gnu_cxx::__int_traits<_Tp>::____is_signed;
>  #endif
>
>    // Generic implementation for arbitrary bases.
> diff --git a/libstdc++-v3/include/bits/locale_facets.tcc b/libstdc++-v3/include/bits/locale_facets.tcc
> index 6bfff7d6289..0e62bc89397 100644
> --- a/libstdc++-v3/include/bits/locale_facets.tcc
> +++ b/libstdc++-v3/include/bits/locale_facets.tcc
> @@ -470,7 +470,7 @@ _GLIBCXX_BEGIN_NAMESPACE_LDBL
>         bool __testfail = false;
>         bool __testoverflow = false;
>         const __unsigned_type __max =
> -         (__negative && __num_traits::__is_signed)
> +         (__negative && __num_traits::____is_signed)
>           ? -static_cast<__unsigned_type>(__num_traits::__min)
>           : __num_traits::__max;
>         const __unsigned_type __smax = __max / __base;
> @@ -573,7 +573,7 @@ _GLIBCXX_BEGIN_NAMESPACE_LDBL
>           }
>         else if (__testoverflow)
>           {
> -           if (__negative && __num_traits::__is_signed)
> +           if (__negative && __num_traits::____is_signed)
>               __v = __num_traits::__min;
>             else
>               __v = __num_traits::__max;
> @@ -914,7 +914,7 @@ _GLIBCXX_BEGIN_NAMESPACE_LDBL
>             if (__v >= 0)
>               {
>                 if (bool(__flags & ios_base::showpos)
> -                   && __gnu_cxx::__numeric_traits<_ValueT>::__is_signed)
> +                   && __gnu_cxx::__numeric_traits<_ValueT>::____is_signed)
>                   *--__cs = __lit[__num_base::_S_oplus], ++__len;
>               }
>             else
> diff --git a/libstdc++-v3/include/bits/uniform_int_dist.h b/libstdc++-v3/include/bits/uniform_int_dist.h
> index 7ccf930a6d4..b8cfa3c1c71 100644
> --- a/libstdc++-v3/include/bits/uniform_int_dist.h
> +++ b/libstdc++-v3/include/bits/uniform_int_dist.h
> @@ -258,8 +258,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>         {
>           using _Up_traits = __gnu_cxx::__int_traits<_Up>;
>           using _Wp_traits = __gnu_cxx::__int_traits<_Wp>;
> -         static_assert(!_Up_traits::__is_signed, "U must be unsigned");
> -         static_assert(!_Wp_traits::__is_signed, "W must be unsigned");
> +         static_assert(!_Up_traits::____is_signed, "U must be unsigned");
> +         static_assert(!_Wp_traits::____is_signed, "W must be unsigned");
>           static_assert(_Wp_traits::__digits == (2 * _Up_traits::__digits),
>                         "W must be twice as wide as U");
>
> diff --git a/libstdc++-v3/include/ext/numeric_traits.h b/libstdc++-v3/include/ext/numeric_traits.h
> index dcbc2d12927..ce7341be785 100644
> --- a/libstdc++-v3/include/ext/numeric_traits.h
> +++ b/libstdc++-v3/include/ext/numeric_traits.h
> @@ -67,15 +67,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>
>        // NB: these two are also available in std::numeric_limits as compile
>        // time constants, but <limits> is big and we can avoid including it.
> -      static const bool __is_signed = (_Value)(-1) < 0;
> +      static const bool ____is_signed = (_Value)(-1) < 0;
>        static const int __digits
> -       = __is_integer_nonstrict<_Value>::__width - __is_signed;
> +       = __is_integer_nonstrict<_Value>::__width - ____is_signed;
>
>        // The initializers must be constants so that __max and __min are too.
> -      static const _Value __max = __is_signed
> +      static const _Value __max = ____is_signed
>         ? (((((_Value)1 << (__digits - 1)) - 1) << 1) + 1)
>         : ~(_Value)0;
> -      static const _Value __min = __is_signed ? -__max - 1 : (_Value)0;
> +      static const _Value __min = ____is_signed ? -__max - 1 : (_Value)0;
>      };
>
>    template<typename _Value>
> @@ -85,7 +85,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>      const _Value __numeric_traits_integer<_Value>::__max;
>
>    template<typename _Value>
> -    const bool __numeric_traits_integer<_Value>::__is_signed;
> +    const bool __numeric_traits_integer<_Value>::____is_signed;
>
>    template<typename _Value>
>      const int __numeric_traits_integer<_Value>::__digits;
> @@ -161,7 +161,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>        static const int __max_digits10 = __glibcxx_max_digits10(_Value);
>
>        // See above comment...
> -      static const bool __is_signed = true;
> +      static const bool ____is_signed = true;
>        static const int __digits10 = __glibcxx_digits10(_Value);
>        static const int __max_exponent10 = __glibcxx_max_exponent10(_Value);
>      };
> @@ -170,7 +170,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>      const int __numeric_traits_floating<_Value>::__max_digits10;
>
>    template<typename _Value>
> -    const bool __numeric_traits_floating<_Value>::__is_signed;
> +    const bool __numeric_traits_floating<_Value>::____is_signed;
>
>    template<typename _Value>
>      const int __numeric_traits_floating<_Value>::__digits10;
> @@ -210,7 +210,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>      struct __numeric_traits_floating<__ibm128>
>      {
>        static const int __max_digits10 = 33;
> -      static const bool __is_signed = true;
> +      static const bool ____is_signed = true;
>        static const int __digits10 = 31;
>        static const int __max_exponent10 = 308;
>      };
> @@ -224,7 +224,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
>      struct __numeric_traits_floating<__ieee128>
>      {
>        static const int __max_digits10 = 36;
> -      static const bool __is_signed = true;
> +      static const bool ____is_signed = true;
>        static const int __digits10 = 33;
>        static const int __max_exponent10 = 4932;
>      };
> --
> 2.41.0
>


  parent reply	other threads:[~2023-07-12 10:19 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-09  8:47 Ken Matsui
2023-07-09  8:47 ` [PATCH 2/2] libstdc++: use new built-in trait __is_signed Ken Matsui
2023-07-12 10:03   ` Jonathan Wakely
2023-07-09  8:54 ` [PATCH 1/2] c++, libstdc++: implement __is_signed built-in trait Ken Matsui
2023-07-12 10:19 ` Jonathan Wakely [this message]
2023-07-13  1:41   ` Ken Matsui
2023-07-13  1:43     ` [PATCH v2 1/2] c++, libstdc++: Implement " Ken Matsui
2023-07-13  1:43       ` [PATCH v2 2/2] libstdc++: Use new built-in trait __is_signed Ken Matsui

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