[rocPRIM] Make copy_items in rocprim/device/detail /device_batch_memcpy.hpp be compatible with rocThrust iterator for offset parameter

projects/rocprim/rocprim/include/rocprim/device/detail/device_batch_memcpy.hpp

@@ -545,8 +545,14 @@ struct batch_memcpy_impl
                 if(blev_buffer_offset < num_blev_buffers)
                 {
                     auto tile_buffer_id = buffer_by_size_class[blev_buffer_offset].buffer_id;
+                    /* In the case that buffer_size_type is rocthrust::device_reference<T> a static cast to 
+                    / buffer_size_type is needed so that the type passed into ceiling_div is not 
+                    / rocthrust::device_reference<T>. This is possible since rocthrust::device_reference<T>
+                    / can be implicitly cast to type T.
+                    */
+                    buffer_size_type size = static_cast<buffer_size_type>(buffers.sizes[tile_buffer_id]);
                     tile_offsets[i]
-                        = rocprim::detail::ceiling_div(buffers.sizes[tile_buffer_id],
+                        = rocprim::detail::ceiling_div(size,
                                                        blev_block_size * blev_bytes_per_thread);
                 }
                 else
@@ -620,10 +626,15 @@ struct batch_memcpy_impl
                 buffer_offset += warps_per_block)
             {
                 const auto buffer_id = buffers_by_size_class[buffer_offset].buffer_id;
-
+                /* In the case that buffer_size_type is rocthrust::device_reference<T> a static cast to 
+                / buffer_size_type is needed so that the type passed into copy_items is not 
+                / rocthrust::device_reference<T>. This is possible since rocthrust::device_reference<T>
+                / can be implicitly cast to type T.
+                */
+                buffer_size_type size = static_cast<buffer_size_type>(tile_buffers.sizes[buffer_id]);
                 batch_memcpy::copy_items<IsMemCpy>(tile_buffers.srcs[buffer_id],
-                                                   tile_buffers.dsts[buffer_id],
-                                                   tile_buffers.sizes[buffer_id]);
+                            tile_buffers.dsts[buffer_id],
+                            size);
             }
         }