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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 "src/__support/CPP/limits.h" // INT_MAX
13 #include "src/__support/FPUtil/FPBits.h"
14 #include "src/__support/FPUtil/ManipulationFunctions.h"
15 #include "test/UnitTest/FEnvSafeTest.h"
16 #include "test/UnitTest/Test.h"
17 
18 template <typename OutType, typename InType>
19 class LlvmLibcILogbTest : public LIBC_NAMESPACE::testing::FEnvSafeTest {
20   using FPBits = LIBC_NAMESPACE::fputil::FPBits<InType>;
21   using StorageType = typename FPBits::StorageType;
22 
23 public:
24   typedef OutType (*Func)(InType);
25 
test_special_numbers(Func func)26   void test_special_numbers(Func func) {
27     EXPECT_EQ(LIBC_NAMESPACE::fputil::IntLogbConstants<OutType>::FP_LOGB0,
28               func(FPBits::zero(Sign::POS).get_val()));
29     EXPECT_EQ(LIBC_NAMESPACE::fputil::IntLogbConstants<OutType>::FP_LOGB0,
30               func(FPBits::zero(Sign::NEG).get_val()));
31     EXPECT_EQ(LIBC_NAMESPACE::fputil::IntLogbConstants<OutType>::FP_LOGBNAN,
32               func(FPBits::quiet_nan().get_val()));
33     EXPECT_EQ(LIBC_NAMESPACE::fputil::IntLogbConstants<OutType>::T_MAX,
34               func(FPBits::inf(Sign::POS).get_val()));
35     EXPECT_EQ(LIBC_NAMESPACE::fputil::IntLogbConstants<OutType>::T_MAX,
36               func(FPBits::inf(Sign::NEG).get_val()));
37   }
38 
test_powers_of_two(Func func)39   void test_powers_of_two(Func func) {
40     EXPECT_EQ(OutType(0), func(InType(1.0)));
41     EXPECT_EQ(OutType(0), func(InType(-1.0)));
42 
43     EXPECT_EQ(OutType(1), func(InType(2.0)));
44     EXPECT_EQ(OutType(1), func(InType(-2.0)));
45 
46     EXPECT_EQ(OutType(2), func(InType(4.0)));
47     EXPECT_EQ(OutType(2), func(InType(-4.0)));
48 
49     EXPECT_EQ(OutType(3), func(InType(8.0)));
50     EXPECT_EQ(OutType(3), func(-8.0));
51 
52     EXPECT_EQ(OutType(4), func(16.0));
53     EXPECT_EQ(OutType(4), func(-16.0));
54 
55     EXPECT_EQ(OutType(5), func(32.0));
56     EXPECT_EQ(OutType(5), func(-32.0));
57   }
58 
test_some_integers(Func func)59   void test_some_integers(Func func) {
60     EXPECT_EQ(OutType(1), func(InType(3.0)));
61     EXPECT_EQ(OutType(1), func(InType(-3.0)));
62 
63     EXPECT_EQ(OutType(2), func(InType(7.0)));
64     EXPECT_EQ(OutType(2), func(InType(-7.0)));
65 
66     EXPECT_EQ(OutType(3), func(InType(10.0)));
67     EXPECT_EQ(OutType(3), func(InType(-10.0)));
68 
69     EXPECT_EQ(OutType(4), func(InType(31.0)));
70     EXPECT_EQ(OutType(4), func(-31.0));
71 
72     EXPECT_EQ(OutType(5), func(55.0));
73     EXPECT_EQ(OutType(5), func(-55.0));
74   }
75 
test_subnormal_range(Func func)76   void test_subnormal_range(Func func) {
77     constexpr StorageType MIN_SUBNORMAL = FPBits::min_subnormal().uintval();
78     constexpr StorageType MAX_SUBNORMAL = FPBits::max_subnormal().uintval();
79     constexpr StorageType COUNT = 10'001;
80     constexpr StorageType STEP = (MAX_SUBNORMAL - MIN_SUBNORMAL) / COUNT;
81     for (StorageType v = MIN_SUBNORMAL; v <= MAX_SUBNORMAL; v += STEP) {
82       FPBits x_bits = FPBits(v);
83       if (x_bits.is_zero() || x_bits.is_inf_or_nan())
84         continue;
85 
86       InType x = x_bits.get_val();
87 
88       int exponent;
89       LIBC_NAMESPACE::fputil::frexp(x, exponent);
90       ASSERT_EQ(static_cast<OutType>(exponent), func(x) + OutType(1));
91     }
92   }
93 
94   void test_normal_range(Func func) {
95     constexpr StorageType MIN_NORMAL = FPBits::min_normal().uintval();
96     constexpr StorageType MAX_NORMAL = FPBits::max_normal().uintval();
97     constexpr StorageType COUNT = 10'001;
98     constexpr StorageType STEP = (MAX_NORMAL - MIN_NORMAL) / COUNT;
99     for (StorageType v = MIN_NORMAL; v <= MAX_NORMAL; v += STEP) {
100       FPBits x_bits = FPBits(v);
101       if (x_bits.is_zero() || x_bits.is_inf_or_nan())
102         continue;
103 
104       InType x = x_bits.get_val();
105 
106       int exponent;
107       LIBC_NAMESPACE::fputil::frexp(x, exponent);
108       ASSERT_EQ(static_cast<OutType>(exponent), func(x) + OutType(1));
109     }
110   }
111 };
112 
113 #define LIST_INTLOGB_TESTS(OutType, InType, Func)                              \
114   using LlvmLibcIntLogbTest = LlvmLibcILogbTest<OutType, InType>;              \
115   TEST_F(LlvmLibcIntLogbTest, SpecialNumbers) { test_special_numbers(&Func); } \
116   TEST_F(LlvmLibcIntLogbTest, PowersOfTwo) { test_powers_of_two(&Func); }      \
117   TEST_F(LlvmLibcIntLogbTest, SomeIntegers) { test_some_integers(&Func); }     \
118   TEST_F(LlvmLibcIntLogbTest, SubnormalRange) { test_subnormal_range(&Func); } \
119   TEST_F(LlvmLibcIntLogbTest, NormalRange) { test_normal_range(&Func); }       \
120   static_assert(true)
121 
122 #endif // LLVM_LIBC_TEST_SRC_MATH_ILOGBTEST_H
123