Merge pull request #5058 from xoltar/careful-insert_deepcopy

theano/compile/function_module.py

@@ -1044,7 +1044,6 @@ copyreg.pickle(Function, _pickle_Function)
 ###
 # FunctionMaker
 ###
-
 def insert_deepcopy(fgraph, wrapped_inputs, wrapped_outputs):
     """
     Insert deepcopy in the fgraph to break aliasing of outputs
@@ -1060,17 +1059,18 @@ def insert_deepcopy(fgraph, wrapped_inputs, wrapped_outputs):
     # memory contract
 
     # We don't insert deep copy when the output.borrow is True for all
-    # conserned outputs.
+    # concerned outputs.
 
     assert len(wrapped_inputs) == len(fgraph.inputs)
     assert len(wrapped_outputs) == len(fgraph.outputs)
     reason = "insert_deepcopy"
-    updated_fgraph_inputs = [fgraph_i for i, fgraph_i in
-                             zip(wrapped_inputs, fgraph.inputs)
-                             if getattr(i, 'update', False)]
+    updated_fgraph_inputs = set([fgraph_i for i, fgraph_i in
+                                zip(wrapped_inputs, fgraph.inputs)
+                                if getattr(i, 'update', False)])
 
     # We can't use fgraph.inputs as this don't include Constant Value.
     all_graph_inputs = gof.graph.inputs(fgraph.outputs)
+    has_destroyers = hasattr(fgraph, 'get_destroyers_of')
 
     for i in xrange(len(fgraph.outputs)):
         views_of_output_i = set()
@@ -1099,12 +1099,9 @@ def insert_deepcopy(fgraph, wrapped_inputs, wrapped_outputs):
                 #    e.g. in-place computations
                 # b) that j'th input is a shared variable that is also
                 #    being updated
-                if (hasattr(fgraph, 'get_destroyers_of') and
-                        fgraph.get_destroyers_of(input_j)):
-                    continue
                 if input_j in updated_fgraph_inputs:
                     continue
-                if input_j in views_of_output_i:
+                if input_j in views_of_output_i and not (has_destroyers and fgraph.get_destroyers_of(input_j)):
                     # We don't put deep_copy_op if the input and the
                     # output have borrow==True
                     if input_j in fgraph.inputs: