make get_constant_value return constant in one more case needed for a futur test.

theano/tensor/basic.py

@@ -367,8 +367,16 @@ def get_constant_value(v):
             ret = [[None]]
             v.owner.op.perform(v.owner, [const], ret)
             return ret[0][0]
-        if isinstance(v.owner.op, Subtensor) and v.ndim==0 and isinstance(v.owner.inputs[0], TensorConstant):
-            return v.owner.inputs[0].data[v.owner.op.idx_list[0]]
+        if isinstance(v.owner.op, Subtensor) and v.ndim==0:
+            if isinstance(v.owner.inputs[0], TensorConstant):
+                return v.owner.inputs[0].data[v.owner.op.idx_list[0]]
+            #Needed to make better graph in this test.
+            #theano/tensor/tests/test_sharedvar.py:test_shared_options.test_specify_shape_partial
+            if v.owner.inputs[0].owner and isinstance(v.owner.inputs[0].owner.op, Join):
+                ret = v.owner.inputs[0].owner.inputs[v.owner.op.idx_list[0]+1]
+                ret = get_constant_value(ret)
+                #join can cast implicitly its input in some case.
+                return numpy.asarray(ret, dtype=v.type.dtype)
     raise TypeError(v)