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
TEST_F(LlvmLibcLog2Test,SpecialNumbers)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
TEST_F(LlvmLibcLog2Test,TrickyInputs)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
TEST_F(LlvmLibcLog2Test,AllExponents)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
TEST_F(LlvmLibcLog2Test,InDoubleRange)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