xref: /aosp_15_r20/external/llvm-libc/test/src/math/NearbyIntTest.h (revision 71db0c75aadcf003ffe3238005f61d7618a3fead)
1 //===-- Utility class to test different flavors of nearbyint ----*- 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_NEARBYINTTEST_H
10 #define LLVM_LIBC_TEST_SRC_MATH_NEARBYINTTEST_H
11 
12 #include "src/__support/CPP/algorithm.h"
13 #include "src/__support/CPP/array.h"
14 #include "test/UnitTest/FEnvSafeTest.h"
15 #include "test/UnitTest/FPMatcher.h"
16 #include "test/UnitTest/Test.h"
17 #include "utils/MPFRWrapper/MPFRUtils.h"
18 
19 using namespace LIBC_NAMESPACE::fputil::testing;
20 
21 namespace mpfr = LIBC_NAMESPACE::testing::mpfr;
22 
23 template <typename T>
24 class NearbyIntTestTemplate : public LIBC_NAMESPACE::testing::FEnvSafeTest {
25 
26   DECLARE_SPECIAL_CONSTANTS(T)
27 
28   static constexpr LIBC_NAMESPACE::cpp::array<RoundingMode, 4> ROUNDING_MODES =
29       {
30           RoundingMode::Upward,
31           RoundingMode::Downward,
32           RoundingMode::TowardZero,
33           RoundingMode::Nearest,
34       };
35 
36   static constexpr StorageType MIN_SUBNORMAL =
37       FPBits::min_subnormal().uintval();
38   static constexpr StorageType MAX_SUBNORMAL =
39       FPBits::max_subnormal().uintval();
40   static constexpr StorageType MIN_NORMAL = FPBits::min_normal().uintval();
41   static constexpr StorageType MAX_NORMAL = FPBits::max_normal().uintval();
42 
43 public:
44   using NearbyIntFunc = T (*)(T);
45 
test_round_numbers(NearbyIntFunc func)46   void test_round_numbers(NearbyIntFunc func) {
47     for (RoundingMode mode : ROUNDING_MODES) {
48       if (ForceRoundingMode r(mode); r.success) {
49         EXPECT_FP_EQ(func(T(1.0)), mpfr::round(T(1.0), mode));
50         EXPECT_FP_EQ(func(T(-1.0)), mpfr::round(T(-1.0), mode));
51         EXPECT_FP_EQ(func(T(10.0)), mpfr::round(T(10.0), mode));
52         EXPECT_FP_EQ(func(T(-10.0)), mpfr::round(T(-10.0), mode));
53         EXPECT_FP_EQ(func(T(1234.0)), mpfr::round(T(1234.0), mode));
54         EXPECT_FP_EQ(func(T(-1234.0)), mpfr::round(T(-1234.0), mode));
55       }
56     }
57   }
58 
test_fractions(NearbyIntFunc func)59   void test_fractions(NearbyIntFunc func) {
60     for (RoundingMode mode : ROUNDING_MODES) {
61       if (ForceRoundingMode r(mode); r.success) {
62         EXPECT_FP_EQ(func(T(0.5)), mpfr::round(T(0.5), mode));
63         EXPECT_FP_EQ(func(T(-0.5)), mpfr::round(T(-0.5), mode));
64         EXPECT_FP_EQ(func(T(0.115)), mpfr::round(T(0.115), mode));
65         EXPECT_FP_EQ(func(T(-0.115)), mpfr::round(T(-0.115), mode));
66         EXPECT_FP_EQ(func(T(0.715)), mpfr::round(T(0.715), mode));
67         EXPECT_FP_EQ(func(T(-0.715)), mpfr::round(T(-0.715), mode));
68       }
69     }
70   }
71 
test_subnormal_range(NearbyIntFunc func)72   void test_subnormal_range(NearbyIntFunc func) {
73     constexpr int COUNT = 100'001;
74     const StorageType STEP = LIBC_NAMESPACE::cpp::max(
75         static_cast<StorageType>((MAX_SUBNORMAL - MIN_SUBNORMAL) / COUNT),
76         StorageType(1));
77     for (StorageType i = MIN_SUBNORMAL; i <= MAX_SUBNORMAL; i += STEP) {
78       T x = FPBits(i).get_val();
79       for (RoundingMode mode : ROUNDING_MODES) {
80         if (ForceRoundingMode r(mode); r.success) {
81           EXPECT_FP_EQ(func(x), mpfr::round(x, mode));
82         }
83       }
84     }
85   }
86 
87   void test_normal_range(NearbyIntFunc func) {
88     constexpr int COUNT = 100'001;
89     const StorageType STEP = LIBC_NAMESPACE::cpp::max(
90         static_cast<StorageType>((MAX_NORMAL - MIN_NORMAL) / COUNT),
91         StorageType(1));
92     for (StorageType i = MIN_NORMAL; i <= MAX_NORMAL; i += STEP) {
93       FPBits xbits(i);
94       T x = xbits.get_val();
95       // In normal range on x86 platforms, the long double implicit 1 bit can be
96       // zero making the numbers NaN. We will skip them.
97       if (xbits.is_nan())
98         continue;
99 
100       for (RoundingMode mode : ROUNDING_MODES) {
101         if (ForceRoundingMode r(mode); r.success) {
102           EXPECT_FP_EQ(func(x), mpfr::round(x, mode));
103         }
104       }
105     }
106   }
107 };
108 
109 #define LIST_NEARBYINT_TESTS(F, func)                                          \
110   using LlvmLibcNearbyIntTest = NearbyIntTestTemplate<F>;                      \
111   TEST_F(LlvmLibcNearbyIntTest, RoundNumbers) { test_round_numbers(&func); }   \
112   TEST_F(LlvmLibcNearbyIntTest, Fractions) { test_fractions(&func); }          \
113   TEST_F(LlvmLibcNearbyIntTest, SubnormalRange) {                              \
114     test_subnormal_range(&func);                                               \
115   }                                                                            \
116   TEST_F(LlvmLibcNearbyIntTest, NormalRange) { test_normal_range(&func); }
117 
118 #endif // LLVM_LIBC_TEST_SRC_MATH_NEARBYINTTEST_H
119