// Copyright 2020 Google LLC
// SPDX-License-Identifier: Apache-2.0
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// Example of unit test for the "skeleton" library.

#include "third_party/highway/hwy/examples/skeleton.h"

#include <stdint.h>
#include <stdio.h>

#undef HWY_TARGET_INCLUDE
#define HWY_TARGET_INCLUDE "examples/skeleton_test.cc"
#include "third_party/highway/hwy/foreach_target.h"  // IWYU pragma: keep

// Must come after foreach_target.h to avoid redefinition errors.
#include "third_party/highway/hwy/highway.h"
#include "third_party/highway/hwy/nanobenchmark.h"  // Unpredictable1
#include "third_party/highway/hwy/tests/test_util-inl.h"

// Optional: factor out parts of the implementation into *-inl.h
// (must also come after foreach_target.h to avoid redefinition errors)
#include "third_party/highway/hwy/examples/skeleton-inl.h"

HWY_BEFORE_NAMESPACE();
namespace skeleton {
namespace HWY_NAMESPACE {
namespace {

namespace hn = hwy::HWY_NAMESPACE;

// Calls function defined in skeleton.cc.
struct TestFloorLog2 {
  template <class T, class DF>
  HWY_NOINLINE void operator()(T /*unused*/, DF df) {
    const size_t count = 5 * hn::Lanes(df);
    auto in = hwy::AllocateAligned<uint8_t>(count);
    auto expected = hwy::AllocateAligned<uint8_t>(count);
    auto out = hwy::AllocateAligned<uint8_t>(count);
    HWY_ASSERT(in && expected && out);

    hwy::RandomState rng;
    for (size_t i = 0; i < count; ++i) {
      expected[i] = Random32(&rng) & 7;
      in[i] = static_cast<uint8_t>(1u << expected[i]);
    }
    CallFloorLog2(in.get(), count, out.get());
    int sum = 0;
    for (size_t i = 0; i < count; ++i) {
      HWY_ASSERT_EQ(expected[i], out[i]);
      sum += out[i];
    }

    for (size_t i = 0; i < count; ++i) {
      out[i] = static_cast<uint8_t>(hwy::Unpredictable1());
    }

    SavedCallFloorLog2(in.get(), count, out.get());
    for (size_t i = 0; i < count; ++i) {
      HWY_ASSERT_EQ(expected[i], out[i]);
      sum += out[i];
    }

    hwy::PreventElision(sum);
  }
};

HWY_NOINLINE void TestAllFloorLog2() {
  hn::ForPartialVectors<TestFloorLog2>()(float());
}

// Calls function defined in skeleton-inl.h.
struct TestSumMulAdd {
  template <class T, class D>
  HWY_NOINLINE void operator()(T /*unused*/, D d) {
    hwy::RandomState rng;
    const size_t count = 4096;
    HWY_ASSERT_EQ(size_t{0}, count % hn::Lanes(d));
    auto mul = hwy::AllocateAligned<T>(count);
    auto x = hwy::AllocateAligned<T>(count);
    auto add = hwy::AllocateAligned<T>(count);
    HWY_ASSERT(mul && x && add);

    for (size_t i = 0; i < count; ++i) {
      mul[i] = hwy::ConvertScalarTo<T>(Random32(&rng) & 0xF);
      x[i] = hwy::ConvertScalarTo<T>(Random32(&rng) & 0xFF);
      add[i] = hwy::ConvertScalarTo<T>(Random32(&rng) & 0xFF);
    }
    double expected_sum = 0.0;
    for (size_t i = 0; i < count; ++i) {
      expected_sum += hwy::ConvertScalarTo<double>(mul[i]) *
                          hwy::ConvertScalarTo<double>(x[i]) +
                      hwy::ConvertScalarTo<double>(add[i]);
    }

    MulAddLoop(d, mul.get(), add.get(), count, x.get());
    double vector_sum = 0.0;
    for (size_t i = 0; i < count; ++i) {
      vector_sum += hwy::ConvertScalarTo<double>(x[i]);
    }

    if (hwy::IsSame<T, hwy::float16_t>()) {
      // The expected value for float16 will vary based on the underlying
      // implementation (compiler emulation, ARM ACLE __fp16 vs _Float16, etc).
      // In some cases the scalar and vector paths will have different results;
      // we check them against known values where possible, else we ignore them.
#if HWY_COMPILER_CLANG && HWY_NEON_HAVE_F16C
      HWY_ASSERT_EQ(4344240.0, expected_sum);  // Full-width float
      HWY_ASSERT_EQ(4344235.0, vector_sum);    // __fp16
#endif
      return;
    }
    HWY_ASSERT_EQ(4344240.0, expected_sum);
    HWY_ASSERT_EQ(expected_sum, vector_sum);
  }
};

HWY_NOINLINE void TestAllSumMulAdd() {
  hn::ForFloatTypes(hn::ForPartialVectors<TestSumMulAdd>());
}

}  // namespace
// NOLINTNEXTLINE(google-readability-namespace-comments)
}  // namespace HWY_NAMESPACE
}  // namespace skeleton
HWY_AFTER_NAMESPACE();

#if HWY_ONCE
namespace skeleton {
namespace {
HWY_BEFORE_TEST(SkeletonTest);
HWY_EXPORT_AND_TEST_P(SkeletonTest, TestAllFloorLog2);
HWY_EXPORT_AND_TEST_P(SkeletonTest, TestAllSumMulAdd);
HWY_AFTER_TEST();
}  // namespace
}  // namespace skeleton
HWY_TEST_MAIN();
#endif  // HWY_ONCE