c6b2aa1896
## Why
Following up on https://github.com/llvm/llvm-project/pull/105946, this
patch provides the floating point overloads for `std::signbit` as
defined by
[P0533R9](https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p0533r9.pdf).
## What
* Test and add overloads for cv-unqualified floating point types
* Remove constrained overload as it is not needed anymore
* Make use of `template<class = void>` as the universal C runtime (UCRT)
needed for Clang-Cl comes with overloads for all cv-unqualified floating
point types (float, double, long double) for `std::signbit()` by itself
[in the
WinSDK](e012b29924/generation/WinSDK/RecompiledIdlHeaders/ucrt/corecrt_math.h (L309-L322)).
In a certain way, this can be seen as a deviation from the C standard.
We need to work around it as the compilation would otherwise error out
due to duplicated definitions.
92 lines
2.6 KiB
C++
92 lines
2.6 KiB
C++
//===----------------------------------------------------------------------===//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
// bool signbit(floating-point-type x); // constexpr since C++23
|
|
|
|
// We don't control the implementation on windows
|
|
// UNSUPPORTED: windows
|
|
|
|
// These compilers don't support constexpr `__builtin_signbit` yet.
|
|
// UNSUPPORTED: clang-17, clang-18, clang-19, apple-clang-15, apple-clang-16
|
|
|
|
#include <cassert>
|
|
#include <cmath>
|
|
#include <limits>
|
|
|
|
#include "test_macros.h"
|
|
#include "type_algorithms.h"
|
|
|
|
struct TestFloat {
|
|
template <class T>
|
|
static TEST_CONSTEXPR_CXX23 bool test() {
|
|
assert(!std::signbit(T(0)));
|
|
assert(!std::signbit(std::numeric_limits<T>::min()));
|
|
assert(!std::signbit(std::numeric_limits<T>::denorm_min()));
|
|
assert(!std::signbit(std::numeric_limits<T>::max()));
|
|
assert(!std::signbit(std::numeric_limits<T>::infinity()));
|
|
assert(!std::signbit(std::numeric_limits<T>::quiet_NaN()));
|
|
assert(!std::signbit(std::numeric_limits<T>::signaling_NaN()));
|
|
assert(std::signbit(-T(0)));
|
|
assert(std::signbit(-std::numeric_limits<T>::infinity()));
|
|
assert(std::signbit(std::numeric_limits<T>::lowest()));
|
|
|
|
return true;
|
|
}
|
|
|
|
template <class T>
|
|
TEST_CONSTEXPR_CXX23 void operator()() {
|
|
test<T>();
|
|
#if TEST_STD_VER >= 23
|
|
static_assert(test<T>());
|
|
#endif
|
|
}
|
|
};
|
|
|
|
struct TestInt {
|
|
template <class T>
|
|
static TEST_CONSTEXPR_CXX23 bool test() {
|
|
assert(!std::signbit(std::numeric_limits<T>::max()));
|
|
assert(!std::signbit(T(0)));
|
|
if (std::is_unsigned<T>::value) {
|
|
assert(!std::signbit(std::numeric_limits<T>::lowest()));
|
|
} else {
|
|
assert(std::signbit(std::numeric_limits<T>::lowest()));
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
template <class T>
|
|
TEST_CONSTEXPR_CXX23 void operator()() {
|
|
test<T>();
|
|
#if TEST_STD_VER >= 23
|
|
static_assert(test<T>());
|
|
#endif
|
|
}
|
|
};
|
|
|
|
template <typename T>
|
|
struct ConvertibleTo {
|
|
operator T() const { return T(); }
|
|
};
|
|
|
|
int main(int, char**) {
|
|
types::for_each(types::floating_point_types(), TestFloat());
|
|
types::for_each(types::integral_types(), TestInt());
|
|
|
|
// Make sure we can call `std::signbit` with convertible types. This checks
|
|
// whether overloads for all cv-unqualified floating-point types are working
|
|
// as expected.
|
|
{
|
|
assert(!std::signbit(ConvertibleTo<float>()));
|
|
assert(!std::signbit(ConvertibleTo<double>()));
|
|
assert(!std::signbit(ConvertibleTo<long double>()));
|
|
}
|
|
return 0;
|
|
}
|