xref: /aosp_15_r20/external/llvm-libc/test/src/stdfix/ExpTest.h (revision 71db0c75aadcf003ffe3238005f61d7618a3fead)
1 //===-- Utility class to test integer sqrt ----------------------*- 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 #include "test/UnitTest/FPMatcher.h"
10 #include "test/UnitTest/Test.h"
11 
12 #include "src/__support/CPP/bit.h"
13 #include "src/__support/FPUtil/BasicOperations.h"
14 #include "src/__support/fixed_point/fx_rep.h"
15 #include "src/__support/fixed_point/sqrt.h"
16 
17 #include "src/math/exp.h"
18 
19 template <typename T> class ExpTest : public LIBC_NAMESPACE::testing::Test {
20 
21   using FXRep = LIBC_NAMESPACE::fixed_point::FXRep<T>;
22   static constexpr T zero = FXRep::ZERO();
23   static constexpr T one = static_cast<T>(1);
24   static constexpr T eps = FXRep::EPS();
25 
26 public:
27   typedef T (*ExpFunc)(T);
28 
test_special_numbers(ExpFunc func)29   void test_special_numbers(ExpFunc func) {
30     EXPECT_EQ(one, func(T(0)));
31     EXPECT_EQ(FXRep::MAX(), func(T(30)));
32     EXPECT_EQ(zero, func(T(-30)));
33   }
34 
test_range_with_step(ExpFunc func,T step,bool rel_error)35   void test_range_with_step(ExpFunc func, T step, bool rel_error) {
36     constexpr int COUNT = 255;
37     constexpr double ERR = 3.0 * static_cast<double>(eps);
38     double x_d = 0.0;
39     T x = step;
40     for (int i = 0; i < COUNT; ++i) {
41       x += step;
42       x_d = static_cast<double>(x);
43       double y_d = static_cast<double>(func(x));
44       double result = LIBC_NAMESPACE::exp(x_d);
45       double errors = rel_error
46                           ? LIBC_NAMESPACE::fputil::abs((y_d / result) - 1.0)
47                           : LIBC_NAMESPACE::fputil::abs(y_d - result);
48       if (errors > ERR) {
49         // Print out the failure input and output.
50         EXPECT_EQ(x, T(0));
51         EXPECT_EQ(func(x), zero);
52       }
53       ASSERT_TRUE(errors <= ERR);
54     }
55   }
56 
test_positive_range(ExpFunc func)57   void test_positive_range(ExpFunc func) {
58     test_range_with_step(func, T(0x1.0p-6), /*rel_error*/ true);
59   }
60 
test_negative_range(ExpFunc func)61   void test_negative_range(ExpFunc func) {
62     test_range_with_step(func, T(-0x1.0p-6), /*rel_error*/ false);
63   }
64 };
65 
66 #define LIST_EXP_TESTS(Name, T, func)                                          \
67   using LlvmLibcExp##Name##Test = ExpTest<T>;                                  \
68   TEST_F(LlvmLibcExp##Name##Test, SpecialNumbers) {                            \
69     test_special_numbers(&func);                                               \
70   }                                                                            \
71   TEST_F(LlvmLibcExp##Name##Test, PositiveRange) {                             \
72     test_positive_range(&func);                                                \
73   }                                                                            \
74   TEST_F(LlvmLibcExp##Name##Test, NegativeRange) {                             \
75     test_negative_range(&func);                                                \
76   }                                                                            \
77   static_assert(true, "Require semicolon.")
78