xref: /aosp_15_r20/external/llvm-libc/test/src/stdfix/ISqrtTest.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/FPUtil/sqrt.h"
15 #include "src/__support/fixed_point/fx_rep.h"
16 #include "src/__support/fixed_point/sqrt.h"
17 
18 template <typename T> class ISqrtTest : public LIBC_NAMESPACE::testing::Test {
19 
20   using OutType =
21       typename LIBC_NAMESPACE::fixed_point::internal::SqrtConfig<T>::OutType;
22   using FXRep = LIBC_NAMESPACE::fixed_point::FXRep<OutType>;
23   static constexpr OutType zero = FXRep::ZERO();
24   static constexpr OutType one = static_cast<OutType>(1);
25   static constexpr OutType eps = FXRep::EPS();
26 
27 public:
28   typedef OutType (*SqrtFunc)(T);
29 
testSpecificInput(T input,OutType result,double expected,double tolerance)30   void testSpecificInput(T input, OutType result, double expected,
31                          double tolerance) {
32     double y_d = static_cast<double>(result);
33     double errors = LIBC_NAMESPACE::fputil::abs((y_d / expected) - 1.0);
34     if (errors > tolerance) {
35       // Print out the failure input and output.
36       EXPECT_EQ(input, T(0));
37       EXPECT_EQ(result, zero);
38     }
39     ASSERT_TRUE(errors <= tolerance);
40   }
41 
testSpecialNumbers(SqrtFunc func)42   void testSpecialNumbers(SqrtFunc func) {
43     EXPECT_EQ(zero, func(T(0)));
44 
45     EXPECT_EQ(one, func(T(1)));
46     EXPECT_EQ(static_cast<OutType>(2.0), func(T(4)));
47     EXPECT_EQ(static_cast<OutType>(4.0), func(T(16)));
48     EXPECT_EQ(static_cast<OutType>(16.0), func(T(256)));
49 
50     constexpr int COUNT = 255;
51     constexpr double ERR = 3.0 * static_cast<double>(eps);
52     double x_d = 0.0;
53     T x = 0;
54     for (int i = 0; i < COUNT; ++i) {
55       x_d += 1.0;
56       ++x;
57       OutType result = func(x);
58       double expected = LIBC_NAMESPACE::fputil::sqrt<double>(x_d);
59       testSpecificInput(x, result, expected, ERR);
60     }
61   }
62 };
63 
64 #define LIST_ISQRT_TESTS(Name, T, func)                                        \
65   using LlvmLibcISqrt##Name##Test = ISqrtTest<T>;                              \
66   TEST_F(LlvmLibcISqrt##Name##Test, SpecialNumbers) {                          \
67     testSpecialNumbers(&func);                                                 \
68   }                                                                            \
69   static_assert(true, "Require semicolon.")
70