[libc++] Some fixes to the <bit> utilities.
Fix __bitop_unsigned_integer and rename to __libcpp_is_unsigned_integer.
There are only five unsigned integer types, so we should just list them out.
Also provide `__libcpp_is_signed_integer`, even though the Standard doesn't
consume that trait anywhere yet.
Notice that `concept uniform_random_bit_generator` is specifically specified
to rely on `concept unsigned_integral` and *not* `__is_unsigned_integer`.
Instantiating `std::ranges::sample` with a type `U` satisfying
`uniform_random_bit_generator` where `unsigned_integral<U::result_type>`
and not `__is_unsigned_integer<U::result_type>` is simply IFNDR.
Orthogonally, fix an undefined behavior in std::countr_zero(__uint128_t).
Orthogonally, improve tests for the <bit> manipulation functions.
It was these new tests that detected the bug in countr_zero.
Differential Revision: https://reviews.llvm.org/D102328
NOKEYCHECK=True
GitOrigin-RevId: e130fbe24e5801feba4526ef5b190acbefba7d91
diff --git a/include/bit b/include/bit
index f8c37c3..12c90bb 100644
--- a/include/bit
+++ b/include/bit
@@ -77,49 +77,33 @@
_LIBCPP_BEGIN_NAMESPACE_STD
-
-template <class _Tp>
-using __bitop_unsigned_integer _LIBCPP_NODEBUG_TYPE = integral_constant<bool,
- is_integral<_Tp>::value &&
- is_unsigned<_Tp>::value &&
- _IsNotSame<typename remove_cv<_Tp>::type, bool>::value &&
- _IsNotSame<typename remove_cv<_Tp>::type, signed char>::value &&
- _IsNotSame<typename remove_cv<_Tp>::type, wchar_t>::value &&
- _IsNotSame<typename remove_cv<_Tp>::type, char16_t>::value &&
- _IsNotSame<typename remove_cv<_Tp>::type, char32_t>::value
- >;
-
-
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
_Tp __rotl(_Tp __t, unsigned int __cnt) _NOEXCEPT
{
- static_assert(__bitop_unsigned_integer<_Tp>::value, "__rotl requires unsigned");
+ static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__rotl requires an unsigned integer type");
const unsigned int __dig = numeric_limits<_Tp>::digits;
if ((__cnt % __dig) == 0)
return __t;
return (__t << (__cnt % __dig)) | (__t >> (__dig - (__cnt % __dig)));
}
-
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
_Tp __rotr(_Tp __t, unsigned int __cnt) _NOEXCEPT
{
- static_assert(__bitop_unsigned_integer<_Tp>::value, "__rotr requires unsigned");
+ static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__rotr requires an unsigned integer type");
const unsigned int __dig = numeric_limits<_Tp>::digits;
if ((__cnt % __dig) == 0)
return __t;
return (__t >> (__cnt % __dig)) | (__t << (__dig - (__cnt % __dig)));
}
-
-
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
int __countr_zero(_Tp __t) _NOEXCEPT
{
- static_assert(__bitop_unsigned_integer<_Tp>::value, "__countr_zero requires unsigned");
+ static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__countr_zero requires an unsigned integer type");
if (__t == 0)
return numeric_limits<_Tp>::digits;
@@ -132,14 +116,13 @@
else
{
int __ret = 0;
- int __iter = 0;
const unsigned int __ulldigits = numeric_limits<unsigned long long>::digits;
- while ((__iter = __libcpp_ctz(static_cast<unsigned long long>(__t))) == __ulldigits)
+ while (static_cast<unsigned long long>(__t) == 0uLL)
{
- __ret += __iter;
+ __ret += __ulldigits;
__t >>= __ulldigits;
}
- return __ret + __iter;
+ return __ret + __libcpp_ctz(static_cast<unsigned long long>(__t));
}
}
@@ -147,7 +130,7 @@
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
int __countl_zero(_Tp __t) _NOEXCEPT
{
- static_assert(__bitop_unsigned_integer<_Tp>::value, "__countl_zero requires unsigned");
+ static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__countl_zero requires an unsigned integer type");
if (__t == 0)
return numeric_limits<_Tp>::digits;
@@ -179,30 +162,27 @@
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
int __countl_one(_Tp __t) _NOEXCEPT
{
- static_assert(__bitop_unsigned_integer<_Tp>::value, "__countl_one requires unsigned");
+ static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__countl_one requires an unsigned integer type");
return __t != numeric_limits<_Tp>::max()
? __countl_zero(static_cast<_Tp>(~__t))
: numeric_limits<_Tp>::digits;
}
-
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
int __countr_one(_Tp __t) _NOEXCEPT
{
- static_assert(__bitop_unsigned_integer<_Tp>::value, "__countr_one requires unsigned");
+ static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__countr_one requires an unsigned integer type");
return __t != numeric_limits<_Tp>::max()
? __countr_zero(static_cast<_Tp>(~__t))
: numeric_limits<_Tp>::digits;
}
-
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
-int
-__popcount(_Tp __t) _NOEXCEPT
+int __popcount(_Tp __t) _NOEXCEPT
{
- static_assert(__bitop_unsigned_integer<_Tp>::value, "__libcpp_popcount requires unsigned");
+ static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__popcount requires an unsigned integer type");
if (sizeof(_Tp) <= sizeof(unsigned int))
return __libcpp_popcount(static_cast<unsigned int>(__t));
else if (sizeof(_Tp) <= sizeof(unsigned long))
@@ -221,13 +201,12 @@
}
}
-
// integral log base 2
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX11
unsigned __bit_log2(_Tp __t) _NOEXCEPT
{
- static_assert(__bitop_unsigned_integer<_Tp>::value, "__bit_log2 requires unsigned");
+ static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__bit_log2 requires an unsigned integer type");
return numeric_limits<_Tp>::digits - 1 - __countl_zero(__t);
}
@@ -235,80 +214,71 @@
_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR
bool __has_single_bit(_Tp __t) _NOEXCEPT
{
- static_assert(__bitop_unsigned_integer<_Tp>::value, "__has_single_bit requires unsigned");
+ static_assert(__libcpp_is_unsigned_integer<_Tp>::value, "__has_single_bit requires an unsigned integer type");
return __t != 0 && (((__t & (__t - 1)) == 0));
}
-
#if _LIBCPP_STD_VER > 17
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
-enable_if_t<__bitop_unsigned_integer<_Tp>::value, _Tp>
+_EnableIf<__libcpp_is_unsigned_integer<_Tp>::value, _Tp>
rotl(_Tp __t, unsigned int __cnt) noexcept
{
return __rotl(__t, __cnt);
}
-
-// rotr
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
-enable_if_t<__bitop_unsigned_integer<_Tp>::value, _Tp>
+_EnableIf<__libcpp_is_unsigned_integer<_Tp>::value, _Tp>
rotr(_Tp __t, unsigned int __cnt) noexcept
{
return __rotr(__t, __cnt);
}
-
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
-enable_if_t<__bitop_unsigned_integer<_Tp>::value, int>
+_EnableIf<__libcpp_is_unsigned_integer<_Tp>::value, int>
countl_zero(_Tp __t) noexcept
{
return __countl_zero(__t);
}
-
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
-enable_if_t<__bitop_unsigned_integer<_Tp>::value, int>
+_EnableIf<__libcpp_is_unsigned_integer<_Tp>::value, int>
countl_one(_Tp __t) noexcept
{
return __countl_one(__t);
}
-
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
-enable_if_t<__bitop_unsigned_integer<_Tp>::value, int>
+_EnableIf<__libcpp_is_unsigned_integer<_Tp>::value, int>
countr_zero(_Tp __t) noexcept
{
return __countr_zero(__t);
}
-
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
-enable_if_t<__bitop_unsigned_integer<_Tp>::value, int>
+_EnableIf<__libcpp_is_unsigned_integer<_Tp>::value, int>
countr_one(_Tp __t) noexcept
{
return __countr_one(__t);
}
-
template<class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
-enable_if_t<__bitop_unsigned_integer<_Tp>::value, int>
+_EnableIf<__libcpp_is_unsigned_integer<_Tp>::value, int>
popcount(_Tp __t) noexcept
{
return __popcount(__t);
}
-
template <class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
-enable_if_t<__bitop_unsigned_integer<_Tp>::value, bool>
+_EnableIf<__libcpp_is_unsigned_integer<_Tp>::value, bool>
has_single_bit(_Tp __t) noexcept
{
return __has_single_bit(__t);
@@ -316,7 +286,7 @@
template <class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
-enable_if_t<__bitop_unsigned_integer<_Tp>::value, _Tp>
+_EnableIf<__libcpp_is_unsigned_integer<_Tp>::value, _Tp>
bit_floor(_Tp __t) noexcept
{
return __t == 0 ? 0 : _Tp{1} << __bit_log2(__t);
@@ -324,7 +294,7 @@
template <class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
-enable_if_t<__bitop_unsigned_integer<_Tp>::value, _Tp>
+_EnableIf<__libcpp_is_unsigned_integer<_Tp>::value, _Tp>
bit_ceil(_Tp __t) noexcept
{
if (__t < 2) return 1;
@@ -343,7 +313,7 @@
template <class _Tp>
_LIBCPP_INLINE_VISIBILITY constexpr
-enable_if_t<__bitop_unsigned_integer<_Tp>::value, _Tp>
+_EnableIf<__libcpp_is_unsigned_integer<_Tp>::value, _Tp>
bit_width(_Tp __t) noexcept
{
return __t == 0 ? 0 : __bit_log2(__t) + 1;
diff --git a/include/type_traits b/include/type_traits
index 3d0ac45..4e5a6ba 100644
--- a/include/type_traits
+++ b/include/type_traits
@@ -789,6 +789,33 @@
#endif // __has_keyword(__is_integral)
+// __libcpp_is_signed_integer, __libcpp_is_unsigned_integer
+
+// [basic.fundamental] defines five standard signed integer types;
+// __int128_t is an extended signed integer type.
+// The signed and unsigned integer types, plus bool and the
+// five types with "char" in their name, compose the "integral" types.
+
+template <class _Tp> struct __libcpp_is_signed_integer : public false_type {};
+template <> struct __libcpp_is_signed_integer<signed char> : public true_type {};
+template <> struct __libcpp_is_signed_integer<signed short> : public true_type {};
+template <> struct __libcpp_is_signed_integer<signed int> : public true_type {};
+template <> struct __libcpp_is_signed_integer<signed long> : public true_type {};
+template <> struct __libcpp_is_signed_integer<signed long long> : public true_type {};
+#ifndef _LIBCPP_HAS_NO_INT128
+template <> struct __libcpp_is_signed_integer<__int128_t> : public true_type {};
+#endif
+
+template <class _Tp> struct __libcpp_is_unsigned_integer : public false_type {};
+template <> struct __libcpp_is_unsigned_integer<unsigned char> : public true_type {};
+template <> struct __libcpp_is_unsigned_integer<unsigned short> : public true_type {};
+template <> struct __libcpp_is_unsigned_integer<unsigned int> : public true_type {};
+template <> struct __libcpp_is_unsigned_integer<unsigned long> : public true_type {};
+template <> struct __libcpp_is_unsigned_integer<unsigned long long> : public true_type {};
+#ifndef _LIBCPP_HAS_NO_INT128
+template <> struct __libcpp_is_unsigned_integer<__uint128_t> : public true_type {};
+#endif
+
// is_floating_point
template <class _Tp> struct __libcpp_is_floating_point : public false_type {};