countl_one.pass.cpp
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//===----------------------------------------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
// template <class T>
// constexpr int countl_one(T x) noexcept;
// The number of consecutive 1 bits, starting from the most significant bit.
// [ Note: Returns N if x == std::numeric_limits<T>::max(). ]
//
// Remarks: This function shall not participate in overload resolution unless
// T is an unsigned integer type
#include <bit>
#include <cstdint>
#include <type_traits>
#include <cassert>
#include "test_macros.h"
class A{};
enum E1 : unsigned char { rEd };
enum class E2 : unsigned char { red };
template <typename T>
constexpr bool constexpr_test()
{
const int dig = std::numeric_limits<T>::digits;
const T max = std::numeric_limits<T>::max();
return std::countl_one(max) == dig
&& std::countl_one(T(max - 1)) == dig - 1
&& std::countl_one(T(max - 2)) == dig - 2
&& std::countl_one(T(max - 3)) == dig - 2
&& std::countl_one(T(max - 4)) == dig - 3
&& std::countl_one(T(max - 5)) == dig - 3
&& std::countl_one(T(max - 6)) == dig - 3
&& std::countl_one(T(max - 7)) == dig - 3
&& std::countl_one(T(max - 8)) == dig - 4
&& std::countl_one(T(max - 9)) == dig - 4
;
}
template <typename T>
void runtime_test()
{
ASSERT_SAME_TYPE(int, decltype(std::countl_one(T(0))));
ASSERT_NOEXCEPT( std::countl_one(T(0)));
const int dig = std::numeric_limits<T>::digits;
assert( std::countl_one(T(~121)) == dig - 7);
assert( std::countl_one(T(~122)) == dig - 7);
assert( std::countl_one(T(~123)) == dig - 7);
assert( std::countl_one(T(~124)) == dig - 7);
assert( std::countl_one(T(~125)) == dig - 7);
assert( std::countl_one(T(~126)) == dig - 7);
assert( std::countl_one(T(~127)) == dig - 7);
assert( std::countl_one(T(~128)) == dig - 8);
assert( std::countl_one(T(~129)) == dig - 8);
assert( std::countl_one(T(~130)) == dig - 8);
}
int main()
{
{
auto lambda = [](auto x) -> decltype(std::countl_one(x)) {};
using L = decltype(lambda);
static_assert( std::is_invocable_v<L, unsigned char>, "");
static_assert( std::is_invocable_v<L, unsigned int>, "");
static_assert( std::is_invocable_v<L, unsigned long>, "");
static_assert( std::is_invocable_v<L, unsigned long long>, "");
static_assert( std::is_invocable_v<L, uint8_t>, "");
static_assert( std::is_invocable_v<L, uint16_t>, "");
static_assert( std::is_invocable_v<L, uint32_t>, "");
static_assert( std::is_invocable_v<L, uint64_t>, "");
static_assert( std::is_invocable_v<L, size_t>, "");
static_assert( std::is_invocable_v<L, uintmax_t>, "");
static_assert( std::is_invocable_v<L, uintptr_t>, "");
static_assert(!std::is_invocable_v<L, int>, "");
static_assert(!std::is_invocable_v<L, signed int>, "");
static_assert(!std::is_invocable_v<L, long>, "");
static_assert(!std::is_invocable_v<L, long long>, "");
static_assert(!std::is_invocable_v<L, int8_t>, "");
static_assert(!std::is_invocable_v<L, int16_t>, "");
static_assert(!std::is_invocable_v<L, int32_t>, "");
static_assert(!std::is_invocable_v<L, int64_t>, "");
static_assert(!std::is_invocable_v<L, ptrdiff_t>, "");
static_assert(!std::is_invocable_v<L, bool>, "");
static_assert(!std::is_invocable_v<L, signed char>, "");
static_assert(!std::is_invocable_v<L, char16_t>, "");
static_assert(!std::is_invocable_v<L, char32_t>, "");
#ifndef _LIBCPP_HAS_NO_INT128
static_assert( std::is_invocable_v<L, __uint128_t>, "");
static_assert(!std::is_invocable_v<L, __int128_t>, "");
#endif
static_assert(!std::is_invocable_v<L, A>, "");
static_assert(!std::is_invocable_v<L, E1>, "");
static_assert(!std::is_invocable_v<L, E2>, "");
}
static_assert(constexpr_test<unsigned char>(), "");
static_assert(constexpr_test<unsigned short>(), "");
static_assert(constexpr_test<unsigned>(), "");
static_assert(constexpr_test<unsigned long>(), "");
static_assert(constexpr_test<unsigned long long>(), "");
static_assert(constexpr_test<uint8_t>(), "");
static_assert(constexpr_test<uint16_t>(), "");
static_assert(constexpr_test<uint32_t>(), "");
static_assert(constexpr_test<uint64_t>(), "");
static_assert(constexpr_test<size_t>(), "");
static_assert(constexpr_test<uintmax_t>(), "");
static_assert(constexpr_test<uintptr_t>(), "");
#ifndef _LIBCPP_HAS_NO_INT128
static_assert(constexpr_test<__uint128_t>(), "");
#endif
runtime_test<unsigned char>();
runtime_test<unsigned>();
runtime_test<unsigned short>();
runtime_test<unsigned long>();
runtime_test<unsigned long long>();
runtime_test<uint8_t>();
runtime_test<uint16_t>();
runtime_test<uint32_t>();
runtime_test<uint64_t>();
runtime_test<size_t>();
runtime_test<uintmax_t>();
runtime_test<uintptr_t>();
#ifndef _LIBCPP_HAS_NO_INT128
runtime_test<__uint128_t>();
{
const int dig = std::numeric_limits<__uint128_t>::digits;
__uint128_t val = 128;
val <<= 32;
assert( std::countl_one(~val) == dig - 40);
val <<= 2;
assert( std::countl_one(~val) == dig - 42);
val <<= 3;
assert( std::countl_one(~val) == dig - 45);
}
#endif
}