75 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// UNSUPPORTED: c++03, c++11, c++14, c++179// <cmath>10 11// constexpr float lerp(float a, float b, float t) noexcept;12// constexpr double lerp(double a, double b, double t) noexcept;13// constexpr long double lerp(long double a, long double b, long double t) noexcept;14 15#include <cmath>16#include <limits>17#include <type_traits>18#include <cassert>19 20#include "test_macros.h"21#include "fp_compare.h"22 23template <typename T>24constexpr bool constexpr_test()25{26 return std::lerp(T( 0), T(12), T(0)) == T(0)27 && std::lerp(T(12), T( 0), T(0.5)) == T(6)28 && std::lerp(T( 0), T(12), T(2)) == T(24);29}30 31 32template <typename T>33void test()34{35 ASSERT_SAME_TYPE(T, decltype(std::lerp(T(), T(), T())));36 LIBCPP_ASSERT_NOEXCEPT( std::lerp(T(), T(), T()));37 38// constexpr T minV = std::numeric_limits<T>::min();39 constexpr T maxV = std::numeric_limits<T>::max();40 constexpr T inf = std::numeric_limits<T>::infinity();41 42// Things that can be compared exactly43 assert((std::lerp(T( 0), T(12), T(0)) == T(0)));44 assert((std::lerp(T( 0), T(12), T(1)) == T(12)));45 assert((std::lerp(T(12), T( 0), T(0)) == T(12)));46 assert((std::lerp(T(12), T( 0), T(1)) == T(0)));47 48 assert((std::lerp(T( 0), T(12), T(0.5)) == T(6)));49 assert((std::lerp(T(12), T( 0), T(0.5)) == T(6)));50 assert((std::lerp(T( 0), T(12), T(2)) == T(24)));51 assert((std::lerp(T(12), T( 0), T(2)) == T(-12)));52 53 assert((std::lerp(maxV, maxV/10, T(0)) == maxV));54 assert((std::lerp(maxV/10, maxV, T(1)) == maxV));55 56 assert((std::lerp(T(2.3), T(2.3), inf) == T(2.3)));57 58 assert(std::lerp(T( 0), T( 0), T(23)) == T(0));59 assert(std::isnan(std::lerp(T( 0), T( 0), inf)));60}61 62 63int main(int, char**)64{65 static_assert(constexpr_test<float>(), "");66 static_assert(constexpr_test<double>(), "");67 static_assert(constexpr_test<long double>(), "");68 69 test<float>();70 test<double>();71 test<long double>();72 73 return 0;74}75