1 //===-- Unittests for log2 ------------------------------------------------===// 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 9 #include "hdr/math_macros.h" 10 #include "src/__support/FPUtil/FPBits.h" 11 #include "src/errno/libc_errno.h" 12 #include "src/math/log2.h" 13 #include "test/UnitTest/FPMatcher.h" 14 #include "test/UnitTest/Test.h" 15 #include "utils/MPFRWrapper/MPFRUtils.h" 16 17 #include <stdint.h> 18 19 using LlvmLibcLog2Test = LIBC_NAMESPACE::testing::FPTest<double>; 20 21 namespace mpfr = LIBC_NAMESPACE::testing::mpfr; 22 using LIBC_NAMESPACE::testing::tlog; 23 24 TEST_F(LlvmLibcLog2Test, SpecialNumbers) { 25 EXPECT_FP_EQ(aNaN, LIBC_NAMESPACE::log2(aNaN)); 26 EXPECT_FP_EQ(inf, LIBC_NAMESPACE::log2(inf)); 27 EXPECT_FP_IS_NAN_WITH_EXCEPTION(LIBC_NAMESPACE::log2(neg_inf), FE_INVALID); 28 EXPECT_FP_EQ_WITH_EXCEPTION(neg_inf, LIBC_NAMESPACE::log2(0.0), FE_DIVBYZERO); 29 EXPECT_FP_EQ_WITH_EXCEPTION(neg_inf, LIBC_NAMESPACE::log2(-0.0), 30 FE_DIVBYZERO); 31 EXPECT_FP_IS_NAN_WITH_EXCEPTION(LIBC_NAMESPACE::log2(-1.0), FE_INVALID); 32 EXPECT_FP_EQ_ALL_ROUNDING(zero, LIBC_NAMESPACE::log2(1.0)); 33 } 34 35 TEST_F(LlvmLibcLog2Test, TrickyInputs) { 36 constexpr int N = 30; 37 constexpr uint64_t INPUTS[N] = { 38 0x3ff0000000000000, // x = 1.0 39 0x4024000000000000, // x = 10.0 40 0x4059000000000000, // x = 10^2 41 0x408f400000000000, // x = 10^3 42 0x40c3880000000000, // x = 10^4 43 0x40f86a0000000000, // x = 10^5 44 0x412e848000000000, // x = 10^6 45 0x416312d000000000, // x = 10^7 46 0x4197d78400000000, // x = 10^8 47 0x41cdcd6500000000, // x = 10^9 48 0x4202a05f20000000, // x = 10^10 49 0x42374876e8000000, // x = 10^11 50 0x426d1a94a2000000, // x = 10^12 51 0x42a2309ce5400000, // x = 10^13 52 0x42d6bcc41e900000, // x = 10^14 53 0x430c6bf526340000, // x = 10^15 54 0x4341c37937e08000, // x = 10^16 55 0x4376345785d8a000, // x = 10^17 56 0x43abc16d674ec800, // x = 10^18 57 0x43e158e460913d00, // x = 10^19 58 0x4415af1d78b58c40, // x = 10^20 59 0x444b1ae4d6e2ef50, // x = 10^21 60 0x4480f0cf064dd592, // x = 10^22 61 0x3fefffffffef06ad, 0x3fefde0f22c7d0eb, 0x225e7812faadb32f, 62 0x3fee1076964c2903, 0x3fdfe93fff7fceb0, 0x3ff012631ad8df10, 63 0x3fefbfdaa448ed98, 64 }; 65 for (int i = 0; i < N; ++i) { 66 double x = FPBits(INPUTS[i]).get_val(); 67 EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Log2, x, 68 LIBC_NAMESPACE::log2(x), 0.5); 69 } 70 } 71 72 TEST_F(LlvmLibcLog2Test, AllExponents) { 73 double x = 0x1.0p-1074; 74 for (int i = -1074; i < 1024; ++i, x *= 2.0) { 75 ASSERT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Log2, x, 76 LIBC_NAMESPACE::log2(x), 0.5); 77 } 78 } 79 80 TEST_F(LlvmLibcLog2Test, InDoubleRange) { 81 constexpr uint64_t COUNT = 1'001; 82 constexpr uint64_t START = 0x3FD0'0000'0000'0000ULL; // 0.25 83 constexpr uint64_t STOP = 0x4010'0000'0000'0000ULL; // 4.0 84 // constexpr uint64_t START = 0x3FF0'0000'0000'0000ULL; // 1.0 85 // constexpr uint64_t STOP = 0x4000'0000'0000'0000ULL; // 2.0 86 constexpr uint64_t STEP = (STOP - START) / COUNT; 87 88 auto test = [&](mpfr::RoundingMode rounding_mode) { 89 mpfr::ForceRoundingMode __r(rounding_mode); 90 if (!__r.success) 91 return; 92 93 uint64_t fails = 0; 94 uint64_t count = 0; 95 uint64_t cc = 0; 96 double mx, mr = 0.0; 97 double tol = 0.5; 98 99 for (uint64_t i = 0, v = START; i <= COUNT; ++i, v += STEP) { 100 double x = FPBits(v).get_val(); 101 if (FPBits(v).is_nan() || FPBits(v).is_inf() || x < 0.0) 102 continue; 103 LIBC_NAMESPACE::libc_errno = 0; 104 double result = LIBC_NAMESPACE::log2(x); 105 ++cc; 106 if (FPBits(result).is_nan() || FPBits(result).is_inf()) 107 continue; 108 109 ++count; 110 // ASSERT_MPFR_MATCH(mpfr::Operation::Log2, x, result, 0.5); 111 if (!TEST_MPFR_MATCH_ROUNDING_SILENTLY(mpfr::Operation::Log2, x, result, 112 0.5, rounding_mode)) { 113 ++fails; 114 while (!TEST_MPFR_MATCH_ROUNDING_SILENTLY(mpfr::Operation::Log2, x, 115 result, tol, rounding_mode)) { 116 mx = x; 117 mr = result; 118 tol *= 2.0; 119 } 120 } 121 } 122 tlog << " Log2 failed: " << fails << "/" << count << "/" << cc 123 << " tests.\n"; 124 tlog << " Max ULPs is at most: " << static_cast<uint64_t>(tol) << ".\n"; 125 if (fails) { 126 EXPECT_MPFR_MATCH(mpfr::Operation::Log2, mx, mr, 0.5, rounding_mode); 127 } 128 }; 129 130 tlog << " Test Rounding To Nearest...\n"; 131 test(mpfr::RoundingMode::Nearest); 132 133 tlog << " Test Rounding Downward...\n"; 134 test(mpfr::RoundingMode::Downward); 135 136 tlog << " Test Rounding Upward...\n"; 137 test(mpfr::RoundingMode::Upward); 138 139 tlog << " Test Rounding Toward Zero...\n"; 140 test(mpfr::RoundingMode::TowardZero); 141 } 142