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 "src/math/exp2f.h"
10 #include "utils/FPUtil/BitPatterns.h"
11 #include "utils/FPUtil/ClassificationFunctions.h"
12 #include "utils/FPUtil/FloatOperations.h"
13 #include "utils/FPUtil/FloatProperties.h"
14 #include "utils/MPFRWrapper/MPFRUtils.h"
15 #include "utils/UnitTest/Test.h"
16 #include <math.h>
17 
18 #include <errno.h>
19 #include <stdint.h>
20 
21 using __llvm_libc::fputil::isNegativeQuietNaN;
22 using __llvm_libc::fputil::isQuietNaN;
23 using __llvm_libc::fputil::valueAsBits;
24 using __llvm_libc::fputil::valueFromBits;
25 
26 using BitPatterns = __llvm_libc::fputil::BitPatterns<float>;
27 
28 namespace mpfr = __llvm_libc::testing::mpfr;
29 
30 TEST(LlvmLibcexp2fTest, SpecialNumbers) {
31   errno = 0;
32 
33   EXPECT_TRUE(
34       isQuietNaN(__llvm_libc::exp2f(valueFromBits(BitPatterns::aQuietNaN))));
35   EXPECT_EQ(errno, 0);
36 
37   EXPECT_TRUE(isNegativeQuietNaN(
38       __llvm_libc::exp2f(valueFromBits(BitPatterns::aNegativeQuietNaN))));
39   EXPECT_EQ(errno, 0);
40 
41   EXPECT_TRUE(isQuietNaN(
42       __llvm_libc::exp2f(valueFromBits(BitPatterns::aSignallingNaN))));
43   EXPECT_EQ(errno, 0);
44 
45   EXPECT_TRUE(isNegativeQuietNaN(
46       __llvm_libc::exp2f(valueFromBits(BitPatterns::aNegativeSignallingNaN))));
47   EXPECT_EQ(errno, 0);
48 
49   EXPECT_EQ(BitPatterns::inf,
50             valueAsBits(__llvm_libc::exp2f(valueFromBits(BitPatterns::inf))));
51   EXPECT_EQ(errno, 0);
52 
53   EXPECT_EQ(BitPatterns::zero, valueAsBits(__llvm_libc::exp2f(
54                                    valueFromBits(BitPatterns::negInf))));
55   EXPECT_EQ(errno, 0);
56 
57   EXPECT_EQ(BitPatterns::one,
58             valueAsBits(__llvm_libc::exp2f(valueFromBits(BitPatterns::zero))));
59   EXPECT_EQ(errno, 0);
60 
61   EXPECT_EQ(BitPatterns::one, valueAsBits(__llvm_libc::exp2f(
62                                   valueFromBits(BitPatterns::negZero))));
63   EXPECT_EQ(errno, 0);
64 }
65 
66 TEST(LlvmLibcExpfTest, Overflow) {
67   errno = 0;
68   EXPECT_EQ(BitPatterns::inf,
69             valueAsBits(__llvm_libc::exp2f(valueFromBits(0x7f7fffffU))));
70   EXPECT_EQ(errno, ERANGE);
71 
72   errno = 0;
73   EXPECT_EQ(BitPatterns::inf,
74             valueAsBits(__llvm_libc::exp2f(valueFromBits(0x43000000U))));
75   EXPECT_EQ(errno, ERANGE);
76 
77   errno = 0;
78   EXPECT_EQ(BitPatterns::inf,
79             valueAsBits(__llvm_libc::exp2f(valueFromBits(0x43000001U))));
80   EXPECT_EQ(errno, ERANGE);
81 }
82 
83 // Test with inputs which are the borders of underflow/overflow but still
84 // produce valid results without setting errno.
85 TEST(LlvmLibcExpfTest, Borderline) {
86   float x;
87 
88   errno = 0;
89   x = valueFromBits(0x42fa0001U);
90   EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), 1.0);
91   EXPECT_EQ(errno, 0);
92 
93   x = valueFromBits(0x42ffffffU);
94   EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), 1.0);
95   EXPECT_EQ(errno, 0);
96 
97   x = valueFromBits(0xc2fa0001U);
98   EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), 1.0);
99   EXPECT_EQ(errno, 0);
100 
101   x = valueFromBits(0xc2fc0000U);
102   EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), 1.0);
103   EXPECT_EQ(errno, 0);
104 
105   x = valueFromBits(0xc2fc0001U);
106   EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), 1.0);
107   EXPECT_EQ(errno, 0);
108 
109   x = valueFromBits(0xc3150000U);
110   EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), 1.0);
111   EXPECT_EQ(errno, 0);
112 }
113 
114 TEST(LlvmLibcExpfTest, Underflow) {
115   errno = 0;
116   EXPECT_EQ(BitPatterns::zero,
117             valueAsBits(__llvm_libc::exp2f(valueFromBits(0xff7fffffU))));
118   EXPECT_EQ(errno, ERANGE);
119 
120   errno = 0;
121   float x = valueFromBits(0xc3158000U);
122   EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), 1.0);
123   EXPECT_EQ(errno, ERANGE);
124 
125   errno = 0;
126   x = valueFromBits(0xc3165432U);
127   EXPECT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), 1.0);
128   EXPECT_EQ(errno, ERANGE);
129 }
130 
131 TEST(LlvmLibcexp2fTest, InFloatRange) {
132   constexpr uint32_t count = 1000000;
133   constexpr uint32_t step = UINT32_MAX / count;
134   for (uint32_t i = 0, v = 0; i <= count; ++i, v += step) {
135     float x = valueFromBits(v);
136     if (isnan(x) || isinf(x))
137       continue;
138     errno = 0;
139     float result = __llvm_libc::exp2f(x);
140 
141     // If the computation resulted in an error or did not produce valid result
142     // in the single-precision floating point range, then ignore comparing with
143     // MPFR result as MPFR can still produce valid results because of its
144     // wider precision.
145     if (isnan(result) || isinf(result) || errno != 0)
146       continue;
147     ASSERT_MPFR_MATCH(mpfr::Operation::Exp2, x, __llvm_libc::exp2f(x), 1.0);
148   }
149 }
150