chore: import upstream snapshot with attribution

paddle/phi/kernels/cpu/rrelu_grad_kernel.cc

@@ -0,0 +1,44 @@
+// 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/kernels/rrelu_grad_kernel.h"
+
+#include "paddle/phi/backends/cpu/cpu_context.h"
+#include "paddle/phi/core/kernel_registry.h"
+
+namespace phi {
+
+template <typename T, typename Context>
+void RReluGradKernel(const Context& dev_ctx,
+                     const DenseTensor& x,
+                     const DenseTensor& noise,
+                     const DenseTensor& out_grad,
+                     DenseTensor* x_grad) {
+  const T* n_ptr = noise.data<T>();
+  const T* x_ptr = x.data<T>();
+  const T* out_grad_ptr = out_grad.data<T>();
+  int numel = static_cast<int>(x.numel());
+  if (!x_grad) return;
+
+  int i = 0;
+  T* x_grad_ptr = dev_ctx.template Alloc<T>(x_grad);
+  for (i = 0; i < numel; i++) {
+    x_grad_ptr[i] = x_ptr[i] > 0 ? out_grad_ptr[i] : n_ptr[i] * out_grad_ptr[i];
+  }
+}
+
+}  // namespace phi
+
+PD_REGISTER_KERNEL(
+    rrelu_grad, CPU, ALL_LAYOUT, phi::RReluGradKernel, float, double) {}