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 "src/__support/FPUtil/FPBits.h"
  10 #include "src/math/log2f.h"
  11 #include "test/UnitTest/FPMatcher.h"
  12 #include "test/UnitTest/Test.h"
  13 #include "utils/MPFRWrapper/MPFRUtils.h"
  14 #include <math.h>
  15
  16 #include <errno.h>
  17 #include <stdint.h>
  18
  19 namespace mpfr = __llvm_libc::testing::mpfr;
  20
  21 DECLARE_SPECIAL_CONSTANTS(float)
  22
  23 TEST(LlvmLibcLog2fTest, SpecialNumbers) {
  24   EXPECT_FP_EQ(aNaN, __llvm_libc::log2f(aNaN));
  25   EXPECT_FP_EQ(inf, __llvm_libc::log2f(inf));
  26   EXPECT_FP_IS_NAN_WITH_EXCEPTION(__llvm_libc::log2f(neg_inf), FE_INVALID);
  27   EXPECT_FP_EQ_WITH_EXCEPTION(neg_inf, __llvm_libc::log2f(0.0f), FE_DIVBYZERO);
  28   EXPECT_FP_EQ_WITH_EXCEPTION(neg_inf, __llvm_libc::log2f(-0.0f), FE_DIVBYZERO);
  29   EXPECT_FP_IS_NAN_WITH_EXCEPTION(__llvm_libc::log2f(-1.0f), FE_INVALID);
  30   EXPECT_FP_EQ(zero, __llvm_libc::log2f(1.0f));
  31 }
  32
  33 TEST(LlvmLibcLog2fTest, TrickyInputs) {
  34   constexpr int N = 10;
  35   constexpr uint32_t INPUTS[N] = {
  36       0x3f7d57f5U, 0x3f7e3274U, 0x3f7ed848U, 0x3f7fd6ccU, 0x3f7fffffU,
  37       0x3f80079bU, 0x3f81d0b5U, 0x3f82e602U, 0x3f83c98dU, 0x3f8cba39U};
  38
  39   for (int i = 0; i < N; ++i) {
  40     float x = float(FPBits(INPUTS[i]));
  41     EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Log2, x,
  42                                    __llvm_libc::log2f(x), 0.5);
  43   }
  44 }
  45
  46 TEST(LlvmLibcLog2fTest, InFloatRange) {
  47   constexpr uint32_t COUNT = 1000000;
  48   constexpr uint32_t STEP = UINT32_MAX / COUNT;
  49   for (uint32_t i = 0, v = 0; i <= COUNT; ++i, v += STEP) {
  50     float x = float(FPBits(v));
  51     if (isnan(x) || isinf(x))
  52       continue;
  53     errno = 0;
  54     float result = __llvm_libc::log2f(x);
  55     // If the computation resulted in an error or did not produce valid result
  56     // in the single-precision floating point range, then ignore comparing with
  57     // MPFR result as MPFR can still produce valid results because of its
  58     // wider precision.
  59     if (isnan(result) || isinf(result) || errno != 0)
  60       continue;
  61     ASSERT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Log2, x,
  62                                    __llvm_libc::log2f(x), 0.5);
  63   }
  64 }