chore: import upstream snapshot with attribution

paddle/cinn/backends/custom_device/codegen_custom_device_dev.h

@@ -0,0 +1,44 @@
+// Copyright (c) 2026 CINN 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.
+
+#pragma once
+#include "paddle/cinn/backends/codegen_gpu_dev.h"
+
+namespace cinn {
+namespace backends {
+namespace custom_device {
+
+/**
+ * CUSTOMDEVICE device code generator.
+ *
+ * It generates the device function, e.g, the function called "myadd" will have
+ * a __global__ function called "myadd_kernel", different from codegen_c, the
+ * declaration of the "myadd_kernel" function has an expanded argument list,
+ * which finally similar to `__global__ void myadd(float* __restrict__ A, float*
+ * __restrict__ B, int n);`
+ */
+class CodeGenCustomDevice : public CodeGenGpuDev {
+ public:
+  explicit CodeGenCustomDevice(Target target);
+  static const std::string& GetSourceHeader();
+  void PrintIncludes() override;
+  void Visit(const ir::Min* op) override;
+  void Visit(const ir::Max* op) override;
+
+ private:
+};
+
+}  // namespace custom_device
+}  // namespace backends
+}  // namespace cinn