// Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
//
// 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.

#include "paddle/phi/api/ext/dispatch.h"
#include "paddle/phi/backends/cpu/cpu_context.h"
#include "paddle/phi/common/bfloat16.h"
#include "paddle/phi/common/complex.h"
#include "paddle/phi/core/kernel_registry.h"
#include "paddle/phi/kernels/cpu/elementwise.h"
#include "paddle/phi/kernels/impl/elementwise_kernel_impl.h"

namespace phi {

template <typename T, typename Context>
void SubtractKernel(const Context& dev_ctx,
                    const DenseTensor& x,
                    const DenseTensor& y,
                    DenseTensor* out) {
  dev_ctx.template Alloc<T>(out);
  if (x.dims() == y.dims()) {
    SameDimsElementwiseCompute<SameDimsSubtractFunctor<CPUContext, T>>()(
        dev_ctx, x, y, out);
  } else {
    auto x_dims = x.dims();
    auto y_dims = y.dims();
    if (x_dims.size() >= y_dims.size()) {
      funcs::ElementwiseCompute<funcs::SubtractFunctor<T>, T>(
          dev_ctx, x, y, funcs::SubtractFunctor<T>(), out, -1);
    } else {
      funcs::ElementwiseCompute<funcs::InverseSubtractFunctor<T>, T>(
          dev_ctx, x, y, funcs::InverseSubtractFunctor<T>(), out, -1);
    }
  }
}
}  // namespace phi

using complex64 = ::phi::dtype::complex<float>;
using complex128 = ::phi::dtype::complex<double>;

// NOTE(chenweihang): using bfloat16 will cause redefine with xpu bfloat16
// using bfloat16 = ::phi::dtype::bfloat16;

PD_REGISTER_KERNEL(subtract,
                   CPU,
                   ALL_LAYOUT,
                   phi::SubtractKernel,
                   float,
                   double,
                   int16_t,
                   int,
                   int64_t,
                   complex64,
                   complex128,
                   phi::dtype::bfloat16) {}