chore: import upstream snapshot with attribution

paddle/phi/kernels/gpu/trunc_kernel.cu

@@ -0,0 +1,94 @@
+// 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/trunc_kernel.h"
+#include "paddle/phi/backends/gpu/gpu_context.h"
+#include "paddle/phi/backends/gpu/gpu_info.h"
+#include "paddle/phi/backends/gpu/gpu_launch_config.h"
+#include "paddle/phi/backends/gpu/gpu_primitives.h"
+#include "paddle/phi/common/amp_type_traits.h"
+#include "paddle/phi/core/kernel_registry.h"
+
+namespace phi {
+
+template <typename T>
+class TruncFunctor {
+ public:
+  __device__ TruncFunctor(const T x) : x_(x) {}
+  __device__ T operator()() {
+    using MT = typename MPTypeTrait<T>::Type;
+    return static_cast<T>(trunc(static_cast<MT>(x_)));
+  }
+
+ public:
+  const T x_;
+};
+
+template <>
+class TruncFunctor<int> {
+ public:
+  __device__ TruncFunctor(const int x) : x_(x) {}
+  __device__ int operator()() { return x_; }
+
+ public:
+  const int x_;
+};
+
+template <>
+class TruncFunctor<int64_t> {
+ public:
+  __device__ TruncFunctor(const int64_t x) : x_(x) {}
+  __device__ int64_t operator()() { return x_; }
+
+ public:
+  const int64_t x_;
+};
+
+template <typename T>
+__global__ void Trunc(const T* x, T* out, int64_t N) {
+  CUDA_KERNEL_LOOP_TYPE(index, N, int64_t) {
+    TruncFunctor<T> functor(x[index]);
+    out[index] = functor();
+  }
+}
+
+template <typename T, typename Context>
+void TruncKernel(const Context& dev_ctx,
+                 const DenseTensor& x,
+                 DenseTensor* out) {
+  const auto* x_data = x.data<T>();
+  auto* out_data = dev_ctx.template Alloc<T>(out);
+  if (x.numel() == 0) {
+    return;
+  }
+
+  int64_t numel = x.numel();
+  auto config = backends::gpu::GetGpuLaunchConfig1D(dev_ctx, numel);
+
+  Trunc<<<config.block_per_grid, config.thread_per_block>>>(
+      x_data, out_data, numel);
+}
+
+}  // namespace phi
+
+PD_REGISTER_KERNEL(trunc,
+                   GPU,
+                   ALL_LAYOUT,
+                   phi::TruncKernel,
+                   float,
+                   double,
+                   int,
+                   int64_t,
+                   phi::float16,
+                   phi::bfloat16) {}