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 "include/errno.h"
10 #include "include/math.h"
11 #include "src/errno/llvmlibc_errno.h"
12 #include "src/math/expf.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 TEST(ExpfTest, SpecialNumbers) {
32   llvmlibc_errno = 0;
33 
34   EXPECT_TRUE(
35       isQuietNaN(__llvm_libc::expf(valueFromBits(BitPatterns::aQuietNaN))));
36   EXPECT_EQ(llvmlibc_errno, 0);
37 
38   EXPECT_TRUE(isNegativeQuietNaN(
39       __llvm_libc::expf(valueFromBits(BitPatterns::aNegativeQuietNaN))));
40   EXPECT_EQ(llvmlibc_errno, 0);
41 
42   EXPECT_TRUE(isQuietNaN(
43       __llvm_libc::expf(valueFromBits(BitPatterns::aSignallingNaN))));
44   EXPECT_EQ(llvmlibc_errno, 0);
45 
46   EXPECT_TRUE(isNegativeQuietNaN(
47       __llvm_libc::expf(valueFromBits(BitPatterns::aNegativeSignallingNaN))));
48   EXPECT_EQ(llvmlibc_errno, 0);
49 
50   EXPECT_EQ(BitPatterns::inf,
51             valueAsBits(__llvm_libc::expf(valueFromBits(BitPatterns::inf))));
52   EXPECT_EQ(llvmlibc_errno, 0);
53 
54   EXPECT_EQ(BitPatterns::zero,
55             valueAsBits(__llvm_libc::expf(valueFromBits(BitPatterns::negInf))));
56   EXPECT_EQ(llvmlibc_errno, 0);
57 
58   EXPECT_EQ(BitPatterns::one,
59             valueAsBits(__llvm_libc::expf(valueFromBits(BitPatterns::zero))));
60   EXPECT_EQ(llvmlibc_errno, 0);
61 
62   EXPECT_EQ(BitPatterns::one, valueAsBits(__llvm_libc::expf(
63                                   valueFromBits(BitPatterns::negZero))));
64   EXPECT_EQ(llvmlibc_errno, 0);
65 }
66 
67 TEST(ExpfTest, Overflow) {
68   llvmlibc_errno = 0;
69   EXPECT_EQ(BitPatterns::inf,
70             valueAsBits(__llvm_libc::expf(valueFromBits(0x7f7fffffU))));
71   EXPECT_EQ(llvmlibc_errno, ERANGE);
72 
73   llvmlibc_errno = 0;
74   EXPECT_EQ(BitPatterns::inf,
75             valueAsBits(__llvm_libc::expf(valueFromBits(0x42cffff8U))));
76   EXPECT_EQ(llvmlibc_errno, ERANGE);
77 
78   llvmlibc_errno = 0;
79   EXPECT_EQ(BitPatterns::inf,
80             valueAsBits(__llvm_libc::expf(valueFromBits(0x42d00008U))));
81   EXPECT_EQ(llvmlibc_errno, ERANGE);
82 }
83 
84 TEST(ExpfTest, Underflow) {
85   llvmlibc_errno = 0;
86   EXPECT_EQ(BitPatterns::zero,
87             valueAsBits(__llvm_libc::expf(valueFromBits(0xff7fffffU))));
88   EXPECT_EQ(llvmlibc_errno, ERANGE);
89 
90   llvmlibc_errno = 0;
91   EXPECT_EQ(BitPatterns::zero,
92             valueAsBits(__llvm_libc::expf(valueFromBits(0xc2cffff8U))));
93   EXPECT_EQ(llvmlibc_errno, ERANGE);
94 
95   llvmlibc_errno = 0;
96   EXPECT_EQ(BitPatterns::zero,
97             valueAsBits(__llvm_libc::expf(valueFromBits(0xc2d00008U))));
98   EXPECT_EQ(llvmlibc_errno, ERANGE);
99 }
100 
101 // Test with inputs which are the borders of underflow/overflow but still
102 // produce valid results without setting errno.
103 TEST(ExpfTest, Borderline) {
104   float x;
105 
106   llvmlibc_errno = 0;
107   x = valueFromBits(0x42affff8U);
108   ASSERT_MPFR_MATCH(mpfr::Operation::Exp, x, __llvm_libc::expf(x), 1.0);
109   EXPECT_EQ(llvmlibc_errno, 0);
110 
111   x = valueFromBits(0x42b00008U);
112   ASSERT_MPFR_MATCH(mpfr::Operation::Exp, x, __llvm_libc::expf(x), 1.0);
113   EXPECT_EQ(llvmlibc_errno, 0);
114 
115   x = valueFromBits(0xc2affff8U);
116   ASSERT_MPFR_MATCH(mpfr::Operation::Exp, x, __llvm_libc::expf(x), 1.0);
117   EXPECT_EQ(llvmlibc_errno, 0);
118 
119   x = valueFromBits(0xc2b00008U);
120   ASSERT_MPFR_MATCH(mpfr::Operation::Exp, x, __llvm_libc::expf(x), 1.0);
121   EXPECT_EQ(llvmlibc_errno, 0);
122 }
123 
124 TEST(ExpfTest, InFloatRange) {
125   constexpr uint32_t count = 1000000;
126   constexpr uint32_t step = UINT32_MAX / count;
127   for (uint32_t i = 0, v = 0; i <= count; ++i, v += step) {
128     float x = valueFromBits(v);
129     if (isnan(x) || isinf(x))
130       continue;
131     llvmlibc_errno = 0;
132     float result = __llvm_libc::expf(x);
133 
134     // If the computation resulted in an error or did not produce valid result
135     // in the single-precision floating point range, then ignore comparing with
136     // MPFR result as MPFR can still produce valid results because of its
137     // wider precision.
138     if (isnan(result) || isinf(result) || llvmlibc_errno != 0)
139       continue;
140     ASSERT_MPFR_MATCH(mpfr::Operation::Exp, x, __llvm_libc::expf(x), 1.0);
141   }
142 }
143