1 files changed, 67 insertions, 2 deletions

diff --git a/intern/cycles/device/device_memory.h b/intern/cycles/device/device_memory.h
index 00b2aa864aa..1f63a152458 100644
--- a/intern/cycles/device/device_memory.h
+++ b/intern/cycles/device/device_memory.h
@@ -259,6 +259,8 @@ class device_memory {
   device_ptr original_device_ptr;
   size_t original_device_size;
   Device *original_device;
+  bool need_realloc_;
+  bool modified;
 };
 
 /* Device Only Memory
@@ -329,6 +331,8 @@ template<typename T> class device_vector : public device_memory {
   {
     data_type = device_type_traits<T>::data_type;
     data_elements = device_type_traits<T>::num_elements;
+    modified = true;
+    need_realloc_ = true;
 
     assert(data_elements > 0);
   }
@@ -347,6 +351,7 @@ template<typename T> class device_vector : public device_memory {
       device_free();
       host_free();
       host_pointer = host_alloc(sizeof(T) * new_size);
+      modified = true;
       assert(device_pointer == 0);
     }
 
@@ -400,6 +405,19 @@ template<typename T> class device_vector : public device_memory {
     assert(device_pointer == 0);
   }
 
+  void give_data(array<T> &to)
+  {
+    device_free();
+
+    to.set_data((T *)host_pointer, data_size);
+    data_size = 0;
+    data_width = 0;
+    data_height = 0;
+    data_depth = 0;
+    host_pointer = 0;
+    assert(device_pointer == 0);
+  }
+
   /* Free device and host memory. */
   void free()
   {
@@ -411,10 +429,40 @@ template<typename T> class device_vector : public device_memory {
     data_height = 0;
     data_depth = 0;
     host_pointer = 0;
+    modified = true;
+    need_realloc_ = true;
     assert(device_pointer == 0);
   }
 
-  size_t size()
+  void free_if_need_realloc(bool force_free)
+  {
+    if (need_realloc_ || force_free) {
+      free();
+    }
+  }
+
+  bool is_modified() const
+  {
+    return modified;
+  }
+
+  bool need_realloc()
+  {
+    return need_realloc_;
+  }
+
+  void tag_modified()
+  {
+    modified = true;
+  }
+
+  void tag_realloc()
+  {
+    need_realloc_ = true;
+    tag_modified();
+  }
+
+  size_t size() const
   {
     return data_size;
   }
@@ -432,7 +480,24 @@ template<typename T> class device_vector : public device_memory {
 
   void copy_to_device()
   {
-    device_copy_to();
+    if (data_size != 0) {
+      device_copy_to();
+    }
+  }
+
+  void copy_to_device_if_modified()
+  {
+    if (!modified) {
+      return;
+    }
+
+    copy_to_device();
+  }
+
+  void clear_modified()
+  {
+    modified = false;
+    need_realloc_ = false;
   }
 
   void copy_from_device()