Don't always instantiate new object.

theano/tensor/subtensor.py

@@ -1847,6 +1847,7 @@ class AdvancedSubtensor(Op):
         return [advanced_inc_subtensor(theano.tensor.zeros_like(x), gz,
                                        *rest)] + \
             [DisconnectedType()()] * len(rest)
+advanced_subtensor = AdvancedSubtensor()
 
 
 class AdvancedIncSubtensor(Op):

theano/tensor/var.py

@@ -378,7 +378,7 @@ class _tensor_py_operators:
                         theano.tensor.sharedvar.TensorSharedVariable))):
                 return self.take(arg, axis)
             else:
-                return theano.tensor.subtensor.AdvancedSubtensor()(self, *args)
+                return theano.tensor.subtensor.advanced_subtensor(self, *args)
         else:
             if numpy.newaxis in args:
                 # None (aka np.newaxis) in numpy indexing means to add a