libc/test/src/math/smoke/expm1_test.cpp

//===-- Unittests for e^x - 1 ---------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "hdr/errno_macros.h"
#include "hdr/math_macros.h"
#include "hdr/stdint_proxy.h"
#include "src/__support/FPUtil/FPBits.h"
#include "src/math/expm1.h"
#include "test/UnitTest/FPMatcher.h"
#include "test/UnitTest/Test.h"

using LlvmLibcExpm1Test = LIBC_NAMESPACE::testing::FPTest<double>;

TEST_F(LlvmLibcExpm1Test, SpecialNumbers) {
  EXPECT_FP_EQ_WITH_EXCEPTION(aNaN, LIBC_NAMESPACE::expm1(sNaN), FE_INVALID);
  EXPECT_MATH_ERRNO(0);

  EXPECT_FP_EQ(aNaN, LIBC_NAMESPACE::expm1(aNaN));
  EXPECT_MATH_ERRNO(0);
  EXPECT_FP_EQ(inf, LIBC_NAMESPACE::expm1(inf));
  EXPECT_MATH_ERRNO(0);
  EXPECT_FP_EQ_ALL_ROUNDING(-1.0, LIBC_NAMESPACE::expm1(neg_inf));
  EXPECT_MATH_ERRNO(0);

  EXPECT_FP_EQ_WITH_EXCEPTION(inf, LIBC_NAMESPACE::expm1(0x1.0p20),
                              FE_OVERFLOW);
  EXPECT_MATH_ERRNO(ERANGE);

  EXPECT_FP_EQ_ALL_ROUNDING(zero, LIBC_NAMESPACE::expm1(zero));
  EXPECT_FP_EQ_ALL_ROUNDING(neg_zero, LIBC_NAMESPACE::expm1(neg_zero));
  // |x| < 2^-53, expm1(x) = x
  EXPECT_FP_EQ(-0x1.23456789abcdep-55,
               LIBC_NAMESPACE::expm1(-0x1.23456789abcdep-55));
  EXPECT_FP_EQ(0x1.23456789abcdep-55,
               LIBC_NAMESPACE::expm1(0x1.23456789abcdep-55));
  // log(2^-54)
  EXPECT_FP_EQ(-1.0, LIBC_NAMESPACE::expm1(-0x1.2b708872320e2p5));
}

#ifdef LIBC_TEST_FTZ_DAZ

using namespace LIBC_NAMESPACE::testing;

TEST_F(LlvmLibcExpm1Test, FTZMode) {
  ModifyMXCSR mxcsr(FTZ);

  EXPECT_FP_EQ(0.0, LIBC_NAMESPACE::expm1(min_denormal));
  EXPECT_FP_EQ(0.0, LIBC_NAMESPACE::expm1(max_denormal));
}

TEST_F(LlvmLibcExpm1Test, DAZMode) {
  ModifyMXCSR mxcsr(DAZ);

  EXPECT_FP_EQ(0.0, LIBC_NAMESPACE::expm1(min_denormal));
  EXPECT_FP_EQ(0.0, LIBC_NAMESPACE::expm1(max_denormal));
}

TEST_F(LlvmLibcExpm1Test, FTZDAZMode) {
  ModifyMXCSR mxcsr(FTZ | DAZ);

  EXPECT_FP_EQ(0.0, LIBC_NAMESPACE::expm1(min_denormal));
  EXPECT_FP_EQ(0.0, LIBC_NAMESPACE::expm1(max_denormal));
}

#endif