libc/test/src/math/log2f_test.cpp

   1 //===-- Unittests for log2f -----------------------------------------------===//
   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 "hdr/math_macros.h"
  10 #include "src/__support/FPUtil/FPBits.h"
  11 #include "src/errno/libc_errno.h"
  12 #include "src/math/log2f.h"
  13 #include "test/UnitTest/FPMatcher.h"
  14 #include "test/UnitTest/Test.h"
  15 #include "utils/MPFRWrapper/MPFRUtils.h"
  16
  17 #include <stdint.h>
  18
  19 using LlvmLibcLog2fTest = LIBC_NAMESPACE::testing::FPTest<float>;
  20
  21 namespace mpfr = LIBC_NAMESPACE::testing::mpfr;
  22
  23 TEST_F(LlvmLibcLog2fTest, SpecialNumbers) {
  24   EXPECT_FP_EQ(aNaN, LIBC_NAMESPACE::log2f(aNaN));
  25   EXPECT_FP_EQ(inf, LIBC_NAMESPACE::log2f(inf));
  26   EXPECT_FP_IS_NAN_WITH_EXCEPTION(LIBC_NAMESPACE::log2f(neg_inf), FE_INVALID);
  27   EXPECT_FP_EQ_WITH_EXCEPTION(neg_inf, LIBC_NAMESPACE::log2f(0.0f),
  28                               FE_DIVBYZERO);
  29   EXPECT_FP_EQ_WITH_EXCEPTION(neg_inf, LIBC_NAMESPACE::log2f(-0.0f),
  30                               FE_DIVBYZERO);
  31   EXPECT_FP_IS_NAN_WITH_EXCEPTION(LIBC_NAMESPACE::log2f(-1.0f), FE_INVALID);
  32   EXPECT_FP_EQ_ALL_ROUNDING(zero, LIBC_NAMESPACE::log2f(1.0f));
  33 }
  34
  35 TEST_F(LlvmLibcLog2fTest, TrickyInputs) {
  36   constexpr int N = 10;
  37   constexpr uint32_t INPUTS[N] = {
  38       0x3f7d57f5U, 0x3f7e3274U, 0x3f7ed848U, 0x3f7fd6ccU, 0x3f7fffffU,
  39       0x3f80079bU, 0x3f81d0b5U, 0x3f82e602U, 0x3f83c98dU, 0x3f8cba39U};
  40
  41   for (int i = 0; i < N; ++i) {
  42     float x = FPBits(INPUTS[i]).get_val();
  43     EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Log2, x,
  44                                    LIBC_NAMESPACE::log2f(x), 0.5);
  45   }
  46 }
  47
  48 TEST_F(LlvmLibcLog2fTest, InFloatRange) {
  49   constexpr uint32_t COUNT = 100'000;
  50   constexpr uint32_t STEP = UINT32_MAX / COUNT;
  51   for (uint32_t i = 0, v = 0; i <= COUNT; ++i, v += STEP) {
  52     float x = FPBits(v).get_val();
  53     if (FPBits(v).is_nan() || FPBits(v).is_inf())
  54       continue;
  55     LIBC_NAMESPACE::libc_errno = 0;
  56     float result = LIBC_NAMESPACE::log2f(x);
  57     // If the computation resulted in an error or did not produce valid result
  58     // in the single-precision floating point range, then ignore comparing with
  59     // MPFR result as MPFR can still produce valid results because of its
  60     // wider precision.
  61     if (FPBits(result).is_nan() || FPBits(result).is_inf() ||
  62         LIBC_NAMESPACE::libc_errno != 0)
  63       continue;
  64     ASSERT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Log2, x,
  65                                    LIBC_NAMESPACE::log2f(x), 0.5);
  66   }
  67 }