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-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // UNSUPPORTED: c++03, c++11, c++14, c++17 9 // <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 23 template <typename T> 24 constexpr 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 32 template <typename T> 33 void 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 exactly 43 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 63 int 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