R operator for specify shape

theano/tensor/basic.py

@@ -1782,6 +1782,9 @@ class SpecifyShape(Op):
         return [gz, None]
         return [specify_shape(gz,s), None]
 
+    def R_op(self, inputs, eval_points):
+        return [zeros_like(x) for x in self.make_node(*inputs).outputs ]
+
 specify_shape = SpecifyShape()
 
 class MaxAndArgmax(Op):