1 //===-- Unittests for exp2f -----------------------------------------------===//
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 "include/errno.h"
10 #include "include/math.h"
11 #include "src/errno/llvmlibc_errno.h"
12 #include "src/math/exp2f.h"
13 #include "utils/FPUtil/BitPatterns.h"
14 #include "utils/FPUtil/ClassificationFunctions.h"
15 #include "utils/FPUtil/FloatOperations.h"
16 #include "utils/FPUtil/FloatProperties.h"
17 #include "utils/MPFRWrapper/MPFRUtils.h"
18 #include "utils/UnitTest/Test.h"
19 
20 #include <stdint.h>
21 
22 using __llvm_libc::fputil::isNegativeQuietNaN;
23 using __llvm_libc::fputil::isQuietNaN;
24 using __llvm_libc::fputil::valueAsBits;
25 using __llvm_libc::fputil::valueFromBits;
26 
27 using BitPatterns = __llvm_libc::fputil::BitPatterns<float>;
28 
29 namespace mpfr = __llvm_libc::testing::mpfr;
30 
31 // 12 additional bits of precision over the base precision of a |float|
32 // value.
33 static constexpr mpfr::Tolerance tolerance{mpfr::Tolerance::floatPrecision, 12,
34                                            0xFFF};
35 
36 TEST(exp2fTest, SpecialNumbers) {
37   llvmlibc_errno = 0;
38 
39   EXPECT_TRUE(
40       isQuietNaN(__llvm_libc::exp2f(valueFromBits(BitPatterns::aQuietNaN))));
41   EXPECT_EQ(llvmlibc_errno, 0);
42 
43   EXPECT_TRUE(isNegativeQuietNaN(
44       __llvm_libc::exp2f(valueFromBits(BitPatterns::aNegativeQuietNaN))));
45   EXPECT_EQ(llvmlibc_errno, 0);
46 
47   EXPECT_TRUE(isQuietNaN(
48       __llvm_libc::exp2f(valueFromBits(BitPatterns::aSignallingNaN))));
49   EXPECT_EQ(llvmlibc_errno, 0);
50 
51   EXPECT_TRUE(isNegativeQuietNaN(
52       __llvm_libc::exp2f(valueFromBits(BitPatterns::aNegativeSignallingNaN))));
53   EXPECT_EQ(llvmlibc_errno, 0);
54 
55   EXPECT_EQ(BitPatterns::inf,
56             valueAsBits(__llvm_libc::exp2f(valueFromBits(BitPatterns::inf))));
57   EXPECT_EQ(llvmlibc_errno, 0);
58 
59   EXPECT_EQ(BitPatterns::zero, valueAsBits(__llvm_libc::exp2f(
60                                    valueFromBits(BitPatterns::negInf))));
61   EXPECT_EQ(llvmlibc_errno, 0);
62 
63   EXPECT_EQ(BitPatterns::one,
64             valueAsBits(__llvm_libc::exp2f(valueFromBits(BitPatterns::zero))));
65   EXPECT_EQ(llvmlibc_errno, 0);
66 
67   EXPECT_EQ(BitPatterns::one, valueAsBits(__llvm_libc::exp2f(
68                                   valueFromBits(BitPatterns::negZero))));
69   EXPECT_EQ(llvmlibc_errno, 0);
70 }
71 
72 TEST(ExpfTest, Overflow) {
73   llvmlibc_errno = 0;
74   EXPECT_EQ(BitPatterns::inf,
75             valueAsBits(__llvm_libc::exp2f(valueFromBits(0x7f7fffffU))));
76   EXPECT_EQ(llvmlibc_errno, ERANGE);
77 
78   llvmlibc_errno = 0;
79   EXPECT_EQ(BitPatterns::inf,
80             valueAsBits(__llvm_libc::exp2f(valueFromBits(0x43000000U))));
81   EXPECT_EQ(llvmlibc_errno, ERANGE);
82 
83   llvmlibc_errno = 0;
84   EXPECT_EQ(BitPatterns::inf,
85             valueAsBits(__llvm_libc::exp2f(valueFromBits(0x43000001U))));
86   EXPECT_EQ(llvmlibc_errno, ERANGE);
87 }
88 
89 // Test with inputs which are the borders of underflow/overflow but still
90 // produce valid results without setting errno.
91 TEST(ExpfTest, Borderline) {
92   float x;
93 
94   llvmlibc_errno = 0;
95   x = valueFromBits(0x42fa0001U);
96   EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), tolerance);
97   EXPECT_EQ(llvmlibc_errno, 0);
98 
99   x = valueFromBits(0x42ffffffU);
100   EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), tolerance);
101   EXPECT_EQ(llvmlibc_errno, 0);
102 
103   x = valueFromBits(0xc2fa0001U);
104   EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), tolerance);
105   EXPECT_EQ(llvmlibc_errno, 0);
106 
107   x = valueFromBits(0xc2fc0000U);
108   EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), tolerance);
109   EXPECT_EQ(llvmlibc_errno, 0);
110 
111   x = valueFromBits(0xc2fc0001U);
112   EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), tolerance);
113   EXPECT_EQ(llvmlibc_errno, 0);
114 
115   x = valueFromBits(0xc3150000U);
116   EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), tolerance);
117   EXPECT_EQ(llvmlibc_errno, 0);
118 }
119 
120 TEST(ExpfTest, Underflow) {
121   llvmlibc_errno = 0;
122   EXPECT_EQ(BitPatterns::zero,
123             valueAsBits(__llvm_libc::exp2f(valueFromBits(0xff7fffffU))));
124   EXPECT_EQ(llvmlibc_errno, ERANGE);
125 
126   llvmlibc_errno = 0;
127   float x = valueFromBits(0xc3158000U);
128   EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), tolerance);
129   EXPECT_EQ(llvmlibc_errno, ERANGE);
130 
131   llvmlibc_errno = 0;
132   x = valueFromBits(0xc3165432U);
133   EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), tolerance);
134   EXPECT_EQ(llvmlibc_errno, ERANGE);
135 }
136 
137 TEST(exp2fTest, InFloatRange) {
138   constexpr uint32_t count = 1000000;
139   constexpr uint32_t step = UINT32_MAX / count;
140   for (uint32_t i = 0, v = 0; i <= count; ++i, v += step) {
141     float x = valueFromBits(v);
142     if (isnan(x) || isinf(x))
143       continue;
144     llvmlibc_errno = 0;
145     float result = __llvm_libc::exp2f(x);
146 
147     // If the computation resulted in an error or did not produce valid result
148     // in the single-precision floating point range, then ignore comparing with
149     // MPFR result as MPFR can still produce valid results because of its
150     // wider precision.
151     if (isnan(result) || isinf(result) || llvmlibc_errno != 0)
152       continue;
153     ASSERT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x),
154                       tolerance);
155   }
156 }
157