54 lines · cpp
1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9// UNSUPPORTED: c++03, c++11, c++14, c++1710 11// <type_traits>12 13// constexpr bool is_constant_evaluated() noexcept; // C++2014 15#include <type_traits>16#include <cassert>17 18#include "test_macros.h"19 20#ifndef __cpp_lib_is_constant_evaluated21#if TEST_HAS_BUILTIN(__builtin_is_constant_evaluated)22# error __cpp_lib_is_constant_evaluated should be defined23#endif24#endif25 26// Disable the tautological constant evaluation warnings for this test,27// because it's explicitly testing those cases.28TEST_CLANG_DIAGNOSTIC_IGNORED("-Wconstant-evaluated")29TEST_MSVC_DIAGNOSTIC_IGNORED(5063)30 31template <bool> struct InTemplate {};32 33int main(int, char**)34{35 // Test the signature36 {37 ASSERT_SAME_TYPE(decltype(std::is_constant_evaluated()), bool);38 ASSERT_NOEXCEPT(std::is_constant_evaluated());39 constexpr bool p = std::is_constant_evaluated();40 assert(p);41 }42 // Test the return value of the builtin for basic sanity only. It's the43 // compiler's job to test the builtin for correctness.44 {45 static_assert(std::is_constant_evaluated(), "");46 bool p = std::is_constant_evaluated();47 assert(!p);48 ASSERT_SAME_TYPE(InTemplate<std::is_constant_evaluated()>, InTemplate<true>);49 static int local_static = std::is_constant_evaluated() ? 42 : -1;50 assert(local_static == 42);51 }52 return 0;53}54