1 //===-- Unittests for 2^x -------------------------------------------------===//
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/exp2.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
20 using LlvmLibcExp2Test = LIBC_NAMESPACE::testing::FPTest<double>;
21
22 namespace mpfr = LIBC_NAMESPACE::testing::mpfr;
23 using LIBC_NAMESPACE::testing::tlog;
24
TEST_F(LlvmLibcExp2Test,SpecialNumbers)25 TEST_F(LlvmLibcExp2Test, SpecialNumbers) {
26 EXPECT_FP_EQ(aNaN, LIBC_NAMESPACE::exp2(aNaN));
27 EXPECT_FP_EQ(inf, LIBC_NAMESPACE::exp2(inf));
28 EXPECT_FP_EQ_ALL_ROUNDING(zero, LIBC_NAMESPACE::exp2(neg_inf));
29 EXPECT_FP_EQ_WITH_EXCEPTION(zero, LIBC_NAMESPACE::exp2(-0x1.0p20),
30 FE_UNDERFLOW);
31 EXPECT_FP_EQ_WITH_EXCEPTION(inf, LIBC_NAMESPACE::exp2(0x1.0p20), FE_OVERFLOW);
32 EXPECT_FP_EQ_ALL_ROUNDING(1.0, LIBC_NAMESPACE::exp2(0.0));
33 EXPECT_FP_EQ_ALL_ROUNDING(1.0, LIBC_NAMESPACE::exp2(-0.0));
34 }
35
TEST_F(LlvmLibcExp2Test,TrickyInputs)36 TEST_F(LlvmLibcExp2Test, TrickyInputs) {
37 constexpr int N = 16;
38 constexpr uint64_t INPUTS[N] = {
39 0x3FD79289C6E6A5C0,
40 0x3FD05DE80A173EA0, // 0x1.05de80a173eap-2
41 0xbf1eb7a4cb841fcc, // -0x1.eb7a4cb841fccp-14
42 0xbf19a61fb925970d,
43 0x3fda7b764e2cf47a, // 0x1.a7b764e2cf47ap-2
44 0xc04757852a4b93aa, // -0x1.757852a4b93aap+5
45 0x4044c19e5712e377, // x=0x1.4c19e5712e377p+5
46 0xbf19a61fb925970d, // x=-0x1.9a61fb925970dp-14
47 0xc039a74cdab36c28, // x=-0x1.9a74cdab36c28p+4
48 0xc085b3e4e2e3bba9, // x=-0x1.5b3e4e2e3bba9p+9
49 0xc086960d591aec34, // x=-0x1.6960d591aec34p+9
50 0xc086232c09d58d91, // x=-0x1.6232c09d58d91p+9
51 0xc0874910d52d3051, // x=-0x1.74910d52d3051p9
52 0xc0867a172ceb0990, // x=-0x1.67a172ceb099p+9
53 0xc08ff80000000000, // x=-0x1.ff8p+9
54 0xbc971547652b82fe, // x=-0x1.71547652b82fep-54
55 };
56 for (int i = 0; i < N; ++i) {
57 double x = FPBits(INPUTS[i]).get_val();
58 EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Exp2, x,
59 LIBC_NAMESPACE::exp2(x), 0.5);
60 }
61 }
62
TEST_F(LlvmLibcExp2Test,InDoubleRange)63 TEST_F(LlvmLibcExp2Test, InDoubleRange) {
64 constexpr uint64_t COUNT = 1'231;
65 uint64_t START = LIBC_NAMESPACE::fputil::FPBits<double>(0.25).uintval();
66 uint64_t STOP = LIBC_NAMESPACE::fputil::FPBits<double>(4.0).uintval();
67 uint64_t STEP = (STOP - START) / COUNT;
68
69 auto test = [&](mpfr::RoundingMode rounding_mode) {
70 mpfr::ForceRoundingMode __r(rounding_mode);
71 if (!__r.success)
72 return;
73
74 uint64_t fails = 0;
75 uint64_t count = 0;
76 uint64_t cc = 0;
77 double mx, mr = 0.0;
78 double tol = 0.5;
79
80 for (uint64_t i = 0, v = START; i <= COUNT; ++i, v += STEP) {
81 double x = FPBits(v).get_val();
82 if (isnan(x) || isinf(x) || x < 0.0)
83 continue;
84 LIBC_NAMESPACE::libc_errno = 0;
85 double result = LIBC_NAMESPACE::exp2(x);
86 ++cc;
87 if (isnan(result) || isinf(result))
88 continue;
89
90 ++count;
91
92 if (!TEST_MPFR_MATCH_ROUNDING_SILENTLY(mpfr::Operation::Exp2, x, result,
93 0.5, rounding_mode)) {
94 ++fails;
95 while (!TEST_MPFR_MATCH_ROUNDING_SILENTLY(mpfr::Operation::Exp2, x,
96 result, tol, rounding_mode)) {
97 mx = x;
98 mr = result;
99
100 if (tol > 1000.0)
101 break;
102
103 tol *= 2.0;
104 }
105 }
106 }
107 tlog << " Exp2 failed: " << fails << "/" << count << "/" << cc
108 << " tests.\n";
109 tlog << " Max ULPs is at most: " << static_cast<uint64_t>(tol) << ".\n";
110 if (fails) {
111 EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, mx, mr, 0.5, rounding_mode);
112 }
113 };
114
115 tlog << " Test Rounding To Nearest...\n";
116 test(mpfr::RoundingMode::Nearest);
117
118 tlog << " Test Rounding Downward...\n";
119 test(mpfr::RoundingMode::Downward);
120
121 tlog << " Test Rounding Upward...\n";
122 test(mpfr::RoundingMode::Upward);
123
124 tlog << " Test Rounding Toward Zero...\n";
125 test(mpfr::RoundingMode::TowardZero);
126 }
127