libc/test/src/math/exp_test.cpp

   1 //===-- Unittests for exp -------------------------------------------------===//
   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/exp.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 LlvmLibcExpTest = LIBC_NAMESPACE::testing::FPTest<double>;
  20
  21 namespace mpfr = LIBC_NAMESPACE::testing::mpfr;
  22 using LIBC_NAMESPACE::testing::tlog;
  23
  24 TEST_F(LlvmLibcExpTest, SpecialNumbers) {
  25   EXPECT_FP_EQ(aNaN, LIBC_NAMESPACE::exp(aNaN));
  26   EXPECT_FP_EQ(inf, LIBC_NAMESPACE::exp(inf));
  27   EXPECT_FP_EQ_ALL_ROUNDING(zero, LIBC_NAMESPACE::exp(neg_inf));
  28   EXPECT_FP_EQ_WITH_EXCEPTION(zero, LIBC_NAMESPACE::exp(-0x1.0p20),
  29                               FE_UNDERFLOW);
  30   EXPECT_FP_EQ_WITH_EXCEPTION(inf, LIBC_NAMESPACE::exp(0x1.0p20), FE_OVERFLOW);
  31   EXPECT_FP_EQ_ALL_ROUNDING(1.0, LIBC_NAMESPACE::exp(0.0));
  32   EXPECT_FP_EQ_ALL_ROUNDING(1.0, LIBC_NAMESPACE::exp(-0.0));
  33 }
  34
  35 TEST_F(LlvmLibcExpTest, TrickyInputs) {
  36   constexpr int N = 14;
  37   constexpr uint64_t INPUTS[N] = {
  38       0x3FD79289C6E6A5C0,
  39       0x3FD05DE80A173EA0, // 0x1.05de80a173eap-2
  40       0xbf1eb7a4cb841fcc, // -0x1.eb7a4cb841fccp-14
  41       0xbf19a61fb925970d,
  42       0x3fda7b764e2cf47a, // 0x1.a7b764e2cf47ap-2
  43       0xc04757852a4b93aa, // -0x1.757852a4b93aap+5
  44       0x4044c19e5712e377, // x=0x1.4c19e5712e377p+5
  45       0xbf19a61fb925970d, // x=-0x1.9a61fb925970dp-14
  46       0xc039a74cdab36c28, // x=-0x1.9a74cdab36c28p+4
  47       0xc085b3e4e2e3bba9, // x=-0x1.5b3e4e2e3bba9p+9
  48       0xc086960d591aec34, // x=-0x1.6960d591aec34p+9
  49       0xc086232c09d58d91, // x=-0x1.6232c09d58d91p+9
  50       0xc0874910d52d3051, // x=-0x1.74910d52d3051p9
  51       0xc0867a172ceb0990, // x=-0x1.67a172ceb099p+9
  52   };
  53   for (int i = 0; i < N; ++i) {
  54     double x = FPBits(INPUTS[i]).get_val();
  55     EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Exp, x,
  56                                    LIBC_NAMESPACE::exp(x), 0.5);
  57   }
  58 }
  59
  60 TEST_F(LlvmLibcExpTest, InDoubleRange) {
  61   constexpr uint64_t COUNT = 1'231;
  62   uint64_t START = LIBC_NAMESPACE::fputil::FPBits<double>(0.25).uintval();
  63   uint64_t STOP = LIBC_NAMESPACE::fputil::FPBits<double>(4.0).uintval();
  64   uint64_t STEP = (STOP - START) / COUNT;
  65
  66   auto test = [&](mpfr::RoundingMode rounding_mode) {
  67     mpfr::ForceRoundingMode __r(rounding_mode);
  68     if (!__r.success)
  69       return;
  70
  71     uint64_t fails = 0;
  72     uint64_t count = 0;
  73     uint64_t cc = 0;
  74     double mx, mr = 0.0;
  75     double tol = 0.5;
  76
  77     for (uint64_t i = 0, v = START; i <= COUNT; ++i, v += STEP) {
  78       double x = FPBits(v).get_val();
  79       if (FPBits(v).is_nan() || FPBits(v).is_inf() || x < 0.0)
  80         continue;
  81       LIBC_NAMESPACE::libc_errno = 0;
  82       double result = LIBC_NAMESPACE::exp(x);
  83       ++cc;
  84       if (FPBits(result).is_nan() || FPBits(result).is_inf())
  85         continue;
  86
  87       ++count;
  88       // ASSERT_MPFR_MATCH(mpfr::Operation::Log, x, result, 0.5);
  89       if (!TEST_MPFR_MATCH_ROUNDING_SILENTLY(mpfr::Operation::Exp, x, result,
  90                                              0.5, rounding_mode)) {
  91         ++fails;
  92         while (!TEST_MPFR_MATCH_ROUNDING_SILENTLY(mpfr::Operation::Exp, x,
  93                                                   result, tol, rounding_mode)) {
  94           mx = x;
  95           mr = result;
  96
  97           if (tol > 1000.0)
  98             break;
  99
 100           tol *= 2.0;
 101         }
 102       }
 103     }
 104     tlog << " Exp failed: " << fails << "/" << count << "/" << cc
 105          << " tests.\n";
 106     tlog << "   Max ULPs is at most: " << static_cast<uint64_t>(tol) << ".\n";
 107     if (fails) {
 108       EXPECT_MPFR_MATCH(mpfr::Operation::Exp, mx, mr, 0.5, rounding_mode);
 109     }
 110   };
 111
 112   tlog << " Test Rounding To Nearest...\n";
 113   test(mpfr::RoundingMode::Nearest);
 114
 115   tlog << " Test Rounding Downward...\n";
 116   test(mpfr::RoundingMode::Downward);
 117
 118   tlog << " Test Rounding Upward...\n";
 119   test(mpfr::RoundingMode::Upward);
 120
 121   tlog << " Test Rounding Toward Zero...\n";
 122   test(mpfr::RoundingMode::TowardZero);
 123 }