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[libc++] Extend is_trivially_equality_comparable to integral types with the same signedness and size #70344

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Merged
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Nov 15, 2023
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[libc++] Extend is_trivially_equality_comparable to integral types with the same signedness and size #70344

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11 changes: 10 additions & 1 deletion libcxx/include/__type_traits/is_equality_comparable.h
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Original file line number Diff line number Diff line change
Expand Up @@ -10,9 +10,11 @@
#define _LIBCPP___TYPE_TRAITS_IS_EQUALITY_COMPARABLE_H

#include <__config>
#include <__type_traits/enable_if.h>
#include <__type_traits/integral_constant.h>
#include <__type_traits/is_integral.h>
#include <__type_traits/is_same.h>
#include <__type_traits/is_signed.h>
#include <__type_traits/is_void.h>
#include <__type_traits/remove_cv.h>
#include <__type_traits/remove_cvref.h>
Expand Down Expand Up @@ -44,7 +46,7 @@ struct __is_equality_comparable<_Tp, _Up, __void_t<decltype(std::declval<_Tp>()
// but don't have the same bit-pattern. An exception to this is comparing to a void-pointer. There the bit-pattern is
// always compared.

template <class _Tp, class _Up>
template <class _Tp, class _Up, class = void>
struct __libcpp_is_trivially_equality_comparable_impl : false_type {};

template <class _Tp>
Expand All @@ -57,6 +59,13 @@ struct __libcpp_is_trivially_equality_comparable_impl<_Tp, _Tp>
};
#endif // __has_builtin(__is_trivially_equality_comparable)

template <class _Tp, class _Up>
struct __libcpp_is_trivially_equality_comparable_impl<
_Tp,
_Up,
__enable_if_t<is_integral<_Tp>::value && is_integral<_Up>::value && !is_same<_Tp, _Up>::value &&
is_signed<_Tp>::value == is_signed<_Up>::value && sizeof(_Tp) == sizeof(_Up)> > : true_type {};

template <class _Tp>
struct __libcpp_is_trivially_equality_comparable_impl<_Tp*, _Tp*> : true_type {};

Expand Down
13 changes: 11 additions & 2 deletions libcxx/test/libcxx/type_traits/is_trivially_comparable.compile.pass.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,10 @@
//
//===----------------------------------------------------------------------===//

#include <__type_traits/conditional.h>
#include <__type_traits/is_equality_comparable.h>
#include <__type_traits/is_signed.h>
#include <cstdint>

enum Enum : int {};
enum class EnumClass : int {};
Expand All @@ -19,8 +22,8 @@ static_assert(std::__libcpp_is_trivially_equality_comparable<unsigned int, unsig
static_assert(std::__libcpp_is_trivially_equality_comparable<const unsigned int, unsigned int>::value, "");
static_assert(!std::__libcpp_is_trivially_equality_comparable<unsigned int, int>::value, "");

static_assert(!std::__libcpp_is_trivially_equality_comparable<long, int>::value, "");
static_assert(!std::__libcpp_is_trivially_equality_comparable<int, long>::value, "");
static_assert(!std::__libcpp_is_trivially_equality_comparable<std::int32_t, std::int64_t>::value, "");
static_assert(!std::__libcpp_is_trivially_equality_comparable<std::int64_t, std::int32_t>::value, "");

static_assert(std::__libcpp_is_trivially_equality_comparable<int*, int*>::value, "");
static_assert(std::__libcpp_is_trivially_equality_comparable<int*, void*>::value, "");
Expand All @@ -38,6 +41,12 @@ static_assert(!std::__libcpp_is_trivially_equality_comparable<float, float>::val
static_assert(!std::__libcpp_is_trivially_equality_comparable<double, double>::value, "");
static_assert(!std::__libcpp_is_trivially_equality_comparable<long double, long double>::value, "");

static_assert(std::__libcpp_is_trivially_equality_comparable<
char,
typename std::conditional<std::is_signed<char>::value, signed char, unsigned char>::type>::value,
"");
static_assert(std::__libcpp_is_trivially_equality_comparable<char16_t, std::uint_least16_t>::value, "");

struct S {
char c;
};
Expand Down
21 changes: 21 additions & 0 deletions libcxx/test/std/algorithms/alg.nonmodifying/alg.equal/equal.pass.cpp
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Expand Up @@ -18,6 +18,9 @@
// constexpr bool // constexpr after c++17
// equal(Iter1 first1, Iter1 last1, Iter2 first2, Iter2 last2);

// We test the cartesian product, so we somethimes compare differently signed types
// ADDITIONAL_COMPILE_FLAGS: -Wno-sign-compare

#include <algorithm>
#include <cassert>
#include <functional>
Expand Down Expand Up @@ -131,12 +134,30 @@ TEST_CONSTEXPR_CXX20 bool test() {
struct Base {};
struct Derived : virtual Base {};

struct TestTypes {
template <class T>
struct Test {
template <class U>
void operator()() {
T a[] = {1, 2, 3, 4, 5, 6};
U b[] = {1, 2, 3, 4, 5, 6};
assert(std::equal(a, a + 6, b));
}
};

template <class T>
void operator()() {
types::for_each(types::integer_types(), Test<T>());
}
};

int main(int, char**) {
test();
#if TEST_STD_VER >= 20
static_assert(test());
#endif

types::for_each(types::integer_types(), TestTypes());
types::for_each(types::as_pointers<types::cv_qualified_versions<int> >(),
TestIter2<int, types::as_pointers<types::cv_qualified_versions<int> > >());
types::for_each(types::as_pointers<types::cv_qualified_versions<char> >(),
Expand Down