libc/test/src/math/ILogbTest.h

   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>
  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>
  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>
  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>
  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