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 <errno.h>
18#include <stdint.h>
19
20using LlvmLibcLog2Test = LIBC_NAMESPACE::testing::FPTest<double>;
21
22namespace mpfr = LIBC_NAMESPACE::testing::mpfr;
23using LIBC_NAMESPACE::testing::tlog;
24
25TEST_F(LlvmLibcLog2Test, SpecialNumbers) {
26 EXPECT_FP_EQ(aNaN, LIBC_NAMESPACE::log2(aNaN));
27 EXPECT_FP_EQ(inf, LIBC_NAMESPACE::log2(inf));
28 EXPECT_FP_IS_NAN_WITH_EXCEPTION(LIBC_NAMESPACE::log2(neg_inf), FE_INVALID);
29 EXPECT_FP_EQ_WITH_EXCEPTION(neg_inf, LIBC_NAMESPACE::log2(0.0), FE_DIVBYZERO);
30 EXPECT_FP_EQ_WITH_EXCEPTION(neg_inf, LIBC_NAMESPACE::log2(-0.0),
31 FE_DIVBYZERO);
32 EXPECT_FP_IS_NAN_WITH_EXCEPTION(LIBC_NAMESPACE::log2(-1.0), FE_INVALID);
33 EXPECT_FP_EQ_ALL_ROUNDING(zero, LIBC_NAMESPACE::log2(1.0));
34}
35
36TEST_F(LlvmLibcLog2Test, TrickyInputs) {
37 constexpr int N = 30;
38 constexpr uint64_t INPUTS[N] = {
39 0x3ff0000000000000, // x = 1.0
40 0x4024000000000000, // x = 10.0
41 0x4059000000000000, // x = 10^2
42 0x408f400000000000, // x = 10^3
43 0x40c3880000000000, // x = 10^4
44 0x40f86a0000000000, // x = 10^5
45 0x412e848000000000, // x = 10^6
46 0x416312d000000000, // x = 10^7
47 0x4197d78400000000, // x = 10^8
48 0x41cdcd6500000000, // x = 10^9
49 0x4202a05f20000000, // x = 10^10
50 0x42374876e8000000, // x = 10^11
51 0x426d1a94a2000000, // x = 10^12
52 0x42a2309ce5400000, // x = 10^13
53 0x42d6bcc41e900000, // x = 10^14
54 0x430c6bf526340000, // x = 10^15
55 0x4341c37937e08000, // x = 10^16
56 0x4376345785d8a000, // x = 10^17
57 0x43abc16d674ec800, // x = 10^18
58 0x43e158e460913d00, // x = 10^19
59 0x4415af1d78b58c40, // x = 10^20
60 0x444b1ae4d6e2ef50, // x = 10^21
61 0x4480f0cf064dd592, // x = 10^22
62 0x3fefffffffef06ad, 0x3fefde0f22c7d0eb, 0x225e7812faadb32f,
63 0x3fee1076964c2903, 0x3fdfe93fff7fceb0, 0x3ff012631ad8df10,
64 0x3fefbfdaa448ed98,
65 };
66 for (int i = 0; i < N; ++i) {
67 double x = FPBits(INPUTS[i]).get_val();
68 EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Log2, x,
69 LIBC_NAMESPACE::log2(x), 0.5);
70 }
71}
72
73TEST_F(LlvmLibcLog2Test, AllExponents) {
74 double x = 0x1.0p-1074;
75 for (int i = -1074; i < 1024; ++i, x *= 2.0) {
76 ASSERT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Log2, x,
77 LIBC_NAMESPACE::log2(x), 0.5);
78 }
79}
80
81TEST_F(LlvmLibcLog2Test, InDoubleRange) {
82 constexpr uint64_t COUNT = 1'001;
83 constexpr uint64_t START = 0x3FD0'0000'0000'0000ULL; // 0.25
84 constexpr uint64_t STOP = 0x4010'0000'0000'0000ULL; // 4.0
85 // constexpr uint64_t START = 0x3FF0'0000'0000'0000ULL; // 1.0
86 // constexpr uint64_t STOP = 0x4000'0000'0000'0000ULL; // 2.0
87 constexpr uint64_t STEP = (STOP - START) / COUNT;
88
89 auto test = [&](mpfr::RoundingMode rounding_mode) {
90 mpfr::ForceRoundingMode __r(rounding_mode);
91 if (!__r.success)
92 return;
93
94 uint64_t fails = 0;
95 uint64_t count = 0;
96 uint64_t cc = 0;
97 double mx, mr = 0.0;
98 double tol = 0.5;
99
100 for (uint64_t i = 0, v = START; i <= COUNT; ++i, v += STEP) {
101 double x = FPBits(v).get_val();
102 if (isnan(x: x) || isinf(x: x) || x < 0.0)
103 continue;
104 LIBC_NAMESPACE::libc_errno = 0;
105 double result = LIBC_NAMESPACE::log2(x);
106 ++cc;
107 if (isnan(x: result) || isinf(x: result))
108 continue;
109
110 ++count;
111 // ASSERT_MPFR_MATCH(mpfr::Operation::Log2, x, result, 0.5);
112 if (!TEST_MPFR_MATCH_ROUNDING_SILENTLY(mpfr::Operation::Log2, x, result,
113 0.5, rounding_mode)) {
114 ++fails;
115 while (!TEST_MPFR_MATCH_ROUNDING_SILENTLY(mpfr::Operation::Log2, x,
116 result, tol, rounding_mode)) {
117 mx = x;
118 mr = result;
119 tol *= 2.0;
120 }
121 }
122 }
123 tlog << " Log2 failed: " << fails << "/" << count << "/" << cc
124 << " tests.\n";
125 tlog << " Max ULPs is at most: " << static_cast<uint64_t>(tol) << ".\n";
126 if (fails) {
127 EXPECT_MPFR_MATCH(mpfr::Operation::Log2, mx, mr, 0.5, rounding_mode);
128 }
129 };
130
131 tlog << " Test Rounding To Nearest...\n";
132 test(mpfr::RoundingMode::Nearest);
133
134 tlog << " Test Rounding Downward...\n";
135 test(mpfr::RoundingMode::Downward);
136
137 tlog << " Test Rounding Upward...\n";
138 test(mpfr::RoundingMode::Upward);
139
140 tlog << " Test Rounding Toward Zero...\n";
141 test(mpfr::RoundingMode::TowardZero);
142}
143

source code of libc/test/src/math/log2_test.cpp