xref: /aosp_15_r20/external/llvm-libc/test/src/math/ILogbTest.h (revision 71db0c75aadcf003ffe3238005f61d7618a3fead)
1 //===-- Utility class to test different flavors of ilogb --------*- C++ -*-===//
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 #ifndef LLVM_LIBC_TEST_SRC_MATH_ILOGBTEST_H
10 #define LLVM_LIBC_TEST_SRC_MATH_ILOGBTEST_H
11 
12 #include "hdr/math_macros.h"
13 #include "src/__support/CPP/limits.h" // INT_MAX
14 #include "src/__support/FPUtil/FPBits.h"
15 #include "src/__support/FPUtil/ManipulationFunctions.h"
16 #include "test/UnitTest/FEnvSafeTest.h"
17 #include "test/UnitTest/Test.h"
18 
19 using LIBC_NAMESPACE::Sign;
20 
21 class LlvmLibcILogbTest : public LIBC_NAMESPACE::testing::FEnvSafeTest {
22 public:
23   template <typename T> struct ILogbFunc {
24     typedef int (*Func)(T);
25   };
26 
27   template <typename T>
test_special_numbers(typename ILogbFunc<T>::Func func)28   void test_special_numbers(typename ILogbFunc<T>::Func func) {
29     using FPBits = LIBC_NAMESPACE::fputil::FPBits<T>;
30 
31     EXPECT_EQ(FP_ILOGB0, func(FPBits::zero(Sign::POS).get_val()));
32     EXPECT_EQ(FP_ILOGB0, func(FPBits::zero(Sign::NEG).get_val()));
33     EXPECT_EQ(FP_ILOGBNAN, func(FPBits::quiet_nan().get_val()));
34     EXPECT_EQ(INT_MAX, func(FPBits::inf(Sign::POS).get_val()));
35     EXPECT_EQ(INT_MAX, func(FPBits::inf(Sign::NEG).get_val()));
36   }
37 
38   template <typename T>
test_powers_of_two(typename ILogbFunc<T>::Func func)39   void test_powers_of_two(typename ILogbFunc<T>::Func func) {
40     EXPECT_EQ(0, func(T(1.0)));
41     EXPECT_EQ(0, func(T(-1.0)));
42 
43     EXPECT_EQ(1, func(T(2.0)));
44     EXPECT_EQ(1, func(T(-2.0)));
45 
46     EXPECT_EQ(2, func(T(4.0)));
47     EXPECT_EQ(2, func(T(-4.0)));
48 
49     EXPECT_EQ(3, func(T(8.0)));
50     EXPECT_EQ(3, func(-8.0));
51 
52     EXPECT_EQ(4, func(16.0));
53     EXPECT_EQ(4, func(-16.0));
54 
55     EXPECT_EQ(5, func(32.0));
56     EXPECT_EQ(5, func(-32.0));
57   }
58 
59   template <typename T>
test_some_integers(typename ILogbFunc<T>::Func func)60   void test_some_integers(typename ILogbFunc<T>::Func func) {
61     EXPECT_EQ(1, func(T(3.0)));
62     EXPECT_EQ(1, func(T(-3.0)));
63 
64     EXPECT_EQ(2, func(T(7.0)));
65     EXPECT_EQ(2, func(T(-7.0)));
66 
67     EXPECT_EQ(3, func(T(10.0)));
68     EXPECT_EQ(3, func(T(-10.0)));
69 
70     EXPECT_EQ(4, func(T(31.0)));
71     EXPECT_EQ(4, func(-31.0));
72 
73     EXPECT_EQ(5, func(55.0));
74     EXPECT_EQ(5, func(-55.0));
75   }
76 
77   template <typename T>
test_subnormal_range(typename ILogbFunc<T>::Func func)78   void test_subnormal_range(typename ILogbFunc<T>::Func func) {
79     using FPBits = LIBC_NAMESPACE::fputil::FPBits<T>;
80     using StorageType = typename FPBits::StorageType;
81     constexpr StorageType MIN_SUBNORMAL = FPBits::min_subnormal().uintval();
82     constexpr StorageType MAX_SUBNORMAL = FPBits::max_subnormal().uintval();
83     constexpr StorageType COUNT = 10'001;
84     constexpr StorageType STEP = (MAX_SUBNORMAL - MIN_SUBNORMAL) / COUNT;
85     for (StorageType v = MIN_SUBNORMAL; v <= MAX_SUBNORMAL; v += STEP) {
86       T x = FPBits(v).get_val();
87       if (FPBits(v).is_nan() || FPBits(v).is_inf() || x == 0.0)
88         continue;
89 
90       int exponent;
91       LIBC_NAMESPACE::fputil::frexp(x, exponent);
92       ASSERT_EQ(exponent, func(x) + 1);
93     }
94   }
95 
96   template <typename T>
97   void test_normal_range(typename ILogbFunc<T>::Func func) {
98     using FPBits = LIBC_NAMESPACE::fputil::FPBits<T>;
99     using StorageType = typename FPBits::StorageType;
100     constexpr StorageType MIN_NORMAL = FPBits::min_normal().uintval();
101     constexpr StorageType MAX_NORMAL = FPBits::max_normal().uintval();
102     constexpr StorageType COUNT = 10'001;
103     constexpr StorageType STEP = (MAX_NORMAL - MIN_NORMAL) / COUNT;
104     for (StorageType v = MIN_NORMAL; v <= MAX_NORMAL; v += STEP) {
105       T x = FPBits(v).get_val();
106       if (FPBits(v).is_nan() || FPBits(v).is_inf() || x == 0.0)
107         continue;
108 
109       int exponent;
110       LIBC_NAMESPACE::fputil::frexp(x, exponent);
111       ASSERT_EQ(exponent, func(x) + 1);
112     }
113   }
114 };
115 
116 #endif // LLVM_LIBC_TEST_SRC_MATH_ILOGBTEST_H
117