Bit Operations: P0556, P0553 and P1355. Reviewed as: https://reviews.llvm.org/D51262

llvm-svn: 364862

5 files changed, 843 insertions, 0 deletions

diff --git a/libcxx/test/std/numerics/bit/bitops.count/countl_one.pass.cpp b/libcxx/test/std/numerics/bit/bitops.count/countl_one.pass.cpp
new file mode 100644
index 00000000000..28cb52545c0
--- /dev/null
+++ b/libcxx/test/std/numerics/bit/bitops.count/countl_one.pass.cpp
@@ -0,0 +1,165 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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
+
+}
diff --git a/libcxx/test/std/numerics/bit/bitops.count/countl_zero.pass.cpp b/libcxx/test/std/numerics/bit/bitops.count/countl_zero.pass.cpp
new file mode 100644
index 00000000000..af39dc2905c
--- /dev/null
+++ b/libcxx/test/std/numerics/bit/bitops.count/countl_zero.pass.cpp
@@ -0,0 +1,172 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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_zero(T x) noexcept;
+
+// Returns: The number of consecutive 0 bits, starting from the most significant bit.
+//   [ Note: Returns N if x == 0. ]
+//
+// 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;
+	return std::countl_zero(T(0)) == dig
+	   &&  std::countl_zero(T(1)) == dig - 1
+	   &&  std::countl_zero(T(2)) == dig - 2
+	   &&  std::countl_zero(T(3)) == dig - 2
+	   &&  std::countl_zero(T(4)) == dig - 3
+	   &&  std::countl_zero(T(5)) == dig - 3
+	   &&  std::countl_zero(T(6)) == dig - 3
+	   &&  std::countl_zero(T(7)) == dig - 3
+	   &&  std::countl_zero(T(8)) == dig - 4
+	   &&  std::countl_zero(T(9)) == dig - 4
+	   &&  std::countl_zero(std::numeric_limits<T>::max()) == 0
+	  ;
+}
+
+
+template <typename T>
+void runtime_test()
+{
+	ASSERT_SAME_TYPE(int, decltype(std::countl_zero(T(0))));
+	ASSERT_NOEXCEPT(               std::countl_zero(T(0)));
+	const int dig = std::numeric_limits<T>::digits;
+	
+	assert( std::countl_zero(T(121)) == dig - 7);
+	assert( std::countl_zero(T(122)) == dig - 7);
+	assert( std::countl_zero(T(123)) == dig - 7);
+	assert( std::countl_zero(T(124)) == dig - 7);
+	assert( std::countl_zero(T(125)) == dig - 7);
+	assert( std::countl_zero(T(126)) == dig - 7);
+	assert( std::countl_zero(T(127)) == dig - 7);
+	assert( std::countl_zero(T(128)) == dig - 8);
+	assert( std::countl_zero(T(129)) == dig - 8);
+	assert( std::countl_zero(T(130)) == dig - 8);
+}
+
+int main()
+{
+	
+    {
+    auto lambda = [](auto x) -> decltype(std::countl_zero(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_zero(val-1) == dig - 39);
+	assert( std::countl_zero(val)   == dig - 40);
+	assert( std::countl_zero(val+1) == dig - 40);
+	val <<= 2;
+	assert( std::countl_zero(val-1) == dig - 41);
+	assert( std::countl_zero(val)   == dig - 42);
+	assert( std::countl_zero(val+1) == dig - 42);
+	val <<= 3;
+	assert( std::countl_zero(val-1) == dig - 44);
+	assert( std::countl_zero(val)   == dig - 45);
+	assert( std::countl_zero(val+1) == dig - 45);
+	}
+#endif
+
+}
diff --git a/libcxx/test/std/numerics/bit/bitops.count/countr_one.pass.cpp b/libcxx/test/std/numerics/bit/bitops.count/countr_one.pass.cpp
new file mode 100644
index 00000000000..e82b1f365e1
--- /dev/null
+++ b/libcxx/test/std/numerics/bit/bitops.count/countr_one.pass.cpp
@@ -0,0 +1,170 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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 countr_one(T x) noexcept;
+
+// Returns: The number of consecutive 1 bits, starting from the least 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;
+	return std::countr_one(T(0)) == 0
+	   &&  std::countr_one(T(1)) == 1
+	   &&  std::countr_one(T(2)) == 0
+	   &&  std::countr_one(T(3)) == 2
+	   &&  std::countr_one(T(4)) == 0
+	   &&  std::countr_one(T(5)) == 1
+	   &&  std::countr_one(T(6)) == 0
+	   &&  std::countr_one(T(7)) == 3
+	   &&  std::countr_one(T(8)) == 0
+	   &&  std::countr_one(T(9)) == 1
+	   &&  std::countr_one(std::numeric_limits<T>::max()) == dig
+	  ;
+}
+
+
+template <typename T>
+void runtime_test()
+{
+	ASSERT_SAME_TYPE(int, decltype(std::countr_one(T(0))));
+	ASSERT_NOEXCEPT(               std::countr_one(T(0)));
+	
+	assert( std::countr_one(T(121)) == 1);
+	assert( std::countr_one(T(122)) == 0);
+	assert( std::countr_one(T(123)) == 2);
+	assert( std::countr_one(T(124)) == 0);
+	assert( std::countr_one(T(125)) == 1);
+	assert( std::countr_one(T(126)) == 0);
+	assert( std::countr_one(T(127)) == 7);
+	assert( std::countr_one(T(128)) == 0);
+	assert( std::countr_one(T(129)) == 1);
+	assert( std::countr_one(T(130)) == 0);
+}
+
+int main()
+{
+	
+    {
+    auto lambda = [](auto x) -> decltype(std::countr_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>();
+
+	{
+	__uint128_t val = 128;
+
+	val <<= 32;
+	assert( std::countr_one(val-1) == 39);
+	assert( std::countr_one(val)   ==  0);
+	assert( std::countr_one(val+1) ==  1);
+	val <<= 2;
+	assert( std::countr_one(val-1) == 41);
+	assert( std::countr_one(val)   ==  0);
+	assert( std::countr_one(val+1) ==  1);
+	val <<= 3;
+	assert( std::countr_one(val-1) == 44);
+	assert( std::countr_one(val)   ==  0);
+	assert( std::countr_one(val+1) ==  1);
+	}
+#endif
+
+}
diff --git a/libcxx/test/std/numerics/bit/bitops.count/countr_zero.pass.cpp b/libcxx/test/std/numerics/bit/bitops.count/countr_zero.pass.cpp
new file mode 100644
index 00000000000..8d355bfb51b
--- /dev/null
+++ b/libcxx/test/std/numerics/bit/bitops.count/countr_zero.pass.cpp
@@ -0,0 +1,169 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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 countr_zero(T x) noexcept;
+
+// Returns: The number of consecutive 0 bits, starting from the most significant bit.
+//   [ Note: Returns N if x == 0. ]
+//
+// 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;
+	return std::countr_zero(T(0)) == dig
+	   &&  std::countr_zero(T(1)) == 0
+	   &&  std::countr_zero(T(2)) == 1
+	   &&  std::countr_zero(T(3)) == 0
+	   &&  std::countr_zero(T(4)) == 2
+	   &&  std::countr_zero(T(5)) == 0
+	   &&  std::countr_zero(T(6)) == 1
+	   &&  std::countr_zero(T(7)) == 0
+	   &&  std::countr_zero(T(8)) == 3
+	   &&  std::countr_zero(T(9)) == 0
+	   &&  std::countr_zero(std::numeric_limits<T>::max()) == 0
+	  ;
+}
+
+
+template <typename T>
+void runtime_test()
+{
+	ASSERT_SAME_TYPE(int, decltype(std::countr_zero(T(0))));
+	ASSERT_NOEXCEPT(               std::countr_zero(T(0)));
+	
+	assert( std::countr_zero(T(121)) == 0);
+	assert( std::countr_zero(T(122)) == 1);
+	assert( std::countr_zero(T(123)) == 0);
+	assert( std::countr_zero(T(124)) == 2);
+	assert( std::countr_zero(T(125)) == 0);
+	assert( std::countr_zero(T(126)) == 1);
+	assert( std::countr_zero(T(127)) == 0);
+	assert( std::countr_zero(T(128)) == 7);
+	assert( std::countr_zero(T(129)) == 0);
+	assert( std::countr_zero(T(130)) == 1);
+}
+
+int main()
+{
+	
+    {
+    auto lambda = [](auto x) -> decltype(std::countr_zero(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>();
+
+	{
+	__uint128_t val = 128;
+
+	val <<= 32;
+	assert( std::countr_zero(val-1) ==  0);
+	assert( std::countr_zero(val)   == 39);
+	assert( std::countr_zero(val+1) ==  0);
+	val <<= 2;
+	assert( std::countr_zero(val-1) ==  0);
+	assert( std::countr_zero(val)   == 41);
+	assert( std::countr_zero(val+1) ==  0);
+	val <<= 3;
+	assert( std::countr_zero(val-1) ==  0);
+	assert( std::countr_zero(val)   == 44);
+	assert( std::countr_zero(val+1) ==  0);
+	}
+#endif
+
+}
diff --git a/libcxx/test/std/numerics/bit/bitops.count/popcount.pass.cpp b/libcxx/test/std/numerics/bit/bitops.count/popcount.pass.cpp
new file mode 100644
index 00000000000..e3934a1318d
--- /dev/null
+++ b/libcxx/test/std/numerics/bit/bitops.count/popcount.pass.cpp
@@ -0,0 +1,167 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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 popcount(T x) noexcept;
+
+// Returns: The number of bits set to one in the value of x.
+//
+// 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()
+{
+	return std::popcount(T(0)) == 0
+	   &&  std::popcount(T(1)) == 1
+	   &&  std::popcount(T(2)) == 1
+	   &&  std::popcount(T(3)) == 2
+	   &&  std::popcount(T(4)) == 1
+	   &&  std::popcount(T(5)) == 2
+	   &&  std::popcount(T(6)) == 2
+	   &&  std::popcount(T(7)) == 3
+	   &&  std::popcount(T(8)) == 1
+	   &&  std::popcount(T(9)) == 2
+	   &&  std::popcount(std::numeric_limits<T>::max()) == std::numeric_limits<T>::digits
+	  ;
+}
+
+
+template <typename T>
+void runtime_test()
+{
+	ASSERT_SAME_TYPE(int, decltype(std::popcount(T(0))));
+	ASSERT_NOEXCEPT(               std::popcount(T(0)));
+	
+	assert( std::popcount(T(121)) == 5);
+	assert( std::popcount(T(122)) == 5);
+	assert( std::popcount(T(123)) == 6);
+	assert( std::popcount(T(124)) == 5);
+	assert( std::popcount(T(125)) == 6);
+	assert( std::popcount(T(126)) == 6);
+	assert( std::popcount(T(127)) == 7);
+	assert( std::popcount(T(128)) == 1);
+	assert( std::popcount(T(129)) == 2);
+	assert( std::popcount(T(130)) == 2);
+}
+
+int main()
+{
+	
+    {
+    auto lambda = [](auto x) -> decltype(std::popcount(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>();
+
+	{
+	__uint128_t val = 128;
+
+	val <<= 32;
+	assert( std::popcount(val-1) == 39);
+	assert( std::popcount(val)   ==  1);
+	assert( std::popcount(val+1) ==  2);
+	val <<= 2;
+	assert( std::popcount(val-1) == 41);
+	assert( std::popcount(val)   ==  1);
+	assert( std::popcount(val+1) ==  2);
+	val <<= 3;
+	assert( std::popcount(val-1) == 44);
+	assert( std::popcount(val)   ==  1);
+	assert( std::popcount(val+1) ==  2);
+	}
+#endif
+}