1 //===-- Unittests for expf ------------------------------------------------===//
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/expf.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(LlvmLibcExpfTest, SpecialNumbers) {
31   errno = 0;
32 
33   EXPECT_TRUE(
34       isQuietNaN(__llvm_libc::expf(valueFromBits(BitPatterns::aQuietNaN))));
35   EXPECT_EQ(errno, 0);
36 
37   EXPECT_TRUE(isNegativeQuietNaN(
38       __llvm_libc::expf(valueFromBits(BitPatterns::aNegativeQuietNaN))));
39   EXPECT_EQ(errno, 0);
40 
41   EXPECT_TRUE(isQuietNaN(
42       __llvm_libc::expf(valueFromBits(BitPatterns::aSignallingNaN))));
43   EXPECT_EQ(errno, 0);
44 
45   EXPECT_TRUE(isNegativeQuietNaN(
46       __llvm_libc::expf(valueFromBits(BitPatterns::aNegativeSignallingNaN))));
47   EXPECT_EQ(errno, 0);
48 
49   EXPECT_EQ(BitPatterns::inf,
50             valueAsBits(__llvm_libc::expf(valueFromBits(BitPatterns::inf))));
51   EXPECT_EQ(errno, 0);
52 
53   EXPECT_EQ(BitPatterns::zero,
54             valueAsBits(__llvm_libc::expf(valueFromBits(BitPatterns::negInf))));
55   EXPECT_EQ(errno, 0);
56 
57   EXPECT_EQ(BitPatterns::one,
58             valueAsBits(__llvm_libc::expf(valueFromBits(BitPatterns::zero))));
59   EXPECT_EQ(errno, 0);
60 
61   EXPECT_EQ(BitPatterns::one, valueAsBits(__llvm_libc::expf(
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::expf(valueFromBits(0x7f7fffffU))));
70   EXPECT_EQ(errno, ERANGE);
71 
72   errno = 0;
73   EXPECT_EQ(BitPatterns::inf,
74             valueAsBits(__llvm_libc::expf(valueFromBits(0x42cffff8U))));
75   EXPECT_EQ(errno, ERANGE);
76 
77   errno = 0;
78   EXPECT_EQ(BitPatterns::inf,
79             valueAsBits(__llvm_libc::expf(valueFromBits(0x42d00008U))));
80   EXPECT_EQ(errno, ERANGE);
81 }
82 
83 TEST(LlvmLibcExpfTest, Underflow) {
84   errno = 0;
85   EXPECT_EQ(BitPatterns::zero,
86             valueAsBits(__llvm_libc::expf(valueFromBits(0xff7fffffU))));
87   EXPECT_EQ(errno, ERANGE);
88 
89   errno = 0;
90   EXPECT_EQ(BitPatterns::zero,
91             valueAsBits(__llvm_libc::expf(valueFromBits(0xc2cffff8U))));
92   EXPECT_EQ(errno, ERANGE);
93 
94   errno = 0;
95   EXPECT_EQ(BitPatterns::zero,
96             valueAsBits(__llvm_libc::expf(valueFromBits(0xc2d00008U))));
97   EXPECT_EQ(errno, ERANGE);
98 }
99 
100 // Test with inputs which are the borders of underflow/overflow but still
101 // produce valid results without setting errno.
102 TEST(LlvmLibcExpfTest, Borderline) {
103   float x;
104 
105   errno = 0;
106   x = valueFromBits(0x42affff8U);
107   ASSERT_MPFR_MATCH(mpfr::Operation::Exp, x, __llvm_libc::expf(x), 1.0);
108   EXPECT_EQ(errno, 0);
109 
110   x = valueFromBits(0x42b00008U);
111   ASSERT_MPFR_MATCH(mpfr::Operation::Exp, x, __llvm_libc::expf(x), 1.0);
112   EXPECT_EQ(errno, 0);
113 
114   x = valueFromBits(0xc2affff8U);
115   ASSERT_MPFR_MATCH(mpfr::Operation::Exp, x, __llvm_libc::expf(x), 1.0);
116   EXPECT_EQ(errno, 0);
117 
118   x = valueFromBits(0xc2b00008U);
119   ASSERT_MPFR_MATCH(mpfr::Operation::Exp, x, __llvm_libc::expf(x), 1.0);
120   EXPECT_EQ(errno, 0);
121 }
122 
123 TEST(LlvmLibcExpfTest, InFloatRange) {
124   constexpr uint32_t count = 1000000;
125   constexpr uint32_t step = UINT32_MAX / count;
126   for (uint32_t i = 0, v = 0; i <= count; ++i, v += step) {
127     float x = valueFromBits(v);
128     if (isnan(x) || isinf(x))
129       continue;
130     errno = 0;
131     float result = __llvm_libc::expf(x);
132 
133     // If the computation resulted in an error or did not produce valid result
134     // in the single-precision floating point range, then ignore comparing with
135     // MPFR result as MPFR can still produce valid results because of its
136     // wider precision.
137     if (isnan(result) || isinf(result) || errno != 0)
138       continue;
139     ASSERT_MPFR_MATCH(mpfr::Operation::Exp, x, __llvm_libc::expf(x), 1.0);
140   }
141 }
142