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

llvm-svn: 364862
diff --git a/libcxx/test/std/numerics/bit/bit.pow.two/ispow2.pass.cpp b/libcxx/test/std/numerics/bit/bit.pow.two/ispow2.pass.cpp
new file mode 100644
index 0000000..d65f818
--- /dev/null
+++ b/libcxx/test/std/numerics/bit/bit.pow.two/ispow2.pass.cpp
@@ -0,0 +1,162 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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 bool ispow2(T x) noexcept;
+
+// 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::ispow2(T(1))
+	   &&   std::ispow2(T(2))
+	   &&  !std::ispow2(T(3))
+	   &&   std::ispow2(T(4))
+	   &&  !std::ispow2(T(5))
+	   &&  !std::ispow2(T(6))
+	   &&  !std::ispow2(T(7))
+	   &&   std::ispow2(T(8))
+	   &&  !std::ispow2(T(9))
+	   ;
+}
+
+
+template <typename T>
+void runtime_test()
+{
+	ASSERT_SAME_TYPE(bool, decltype(std::ispow2(T(0))));
+	ASSERT_NOEXCEPT(                std::ispow2(T(0)));
+	
+	assert(!std::ispow2(T(121)));
+	assert(!std::ispow2(T(122)));
+	assert(!std::ispow2(T(123)));
+	assert(!std::ispow2(T(124)));
+	assert(!std::ispow2(T(125)));
+	assert(!std::ispow2(T(126)));
+	assert(!std::ispow2(T(127)));
+	assert( std::ispow2(T(128)));
+	assert(!std::ispow2(T(129)));
+	assert(!std::ispow2(T(130)));
+}
+
+int main()
+{
+	
+    {
+    auto lambda = [](auto x) -> decltype(std::ispow2(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::ispow2(val-1));
+	assert( std::ispow2(val));
+	assert(!std::ispow2(val+1));
+	val <<= 2;
+	assert(!std::ispow2(val-1));
+	assert( std::ispow2(val));
+	assert(!std::ispow2(val+1));
+	val <<= 3;
+	assert(!std::ispow2(val-1));
+	assert( std::ispow2(val));
+	assert(!std::ispow2(val+1));
+	}
+#endif
+	
+}