fix gh-1381 c linker crash with not used inputs.

theano/gof/cc.py

@@ -450,8 +450,13 @@ class CLinker(link.Linker):
         fgraph = self.fgraph
         self.inputs = fgraph.inputs
         self.outputs = fgraph.outputs
+
         # list(fgraph.variables)
-        self.variables = graph.variables(self.inputs, self.outputs)
+        # We need to include the not used inputs in our variables,
+        # otherwise we can't pass them to the module.
+        self.variables = [var for var in self.inputs if not len(var.clients)]
+        self.variables += graph.variables(self.inputs, self.outputs)
+
         # The orphans field is listified to ensure a consistent order.
         #list(fgraph.orphans.difference(self.outputs))
         self.orphans = list(r for r in self.variables
@@ -1180,6 +1185,11 @@ class CLinker(link.Linker):
             op_pos[node] = node_pos
             fgraph_computed_set.update(node.outputs)
 
+        # Add not used input in the key
+        for ipos, var in [(i, var) for i, var in enumerate(fgraph.inputs)
+                          if not len(var.clients)]:
+            sig.append((var.type, in_sig(var, node_pos, ipos)))
+
         #crystalize the signature and version
         sig = tuple(sig)
         version = tuple(version)

theano/gof/tests/test_cc.py

@@ -227,6 +227,18 @@ def test_clinker_dups():
     # note: for now the behavior of fn(2.0, 7.0) is undefined
 
 
+def test_clinker_not_used_inputs():
+    if not theano.config.cxx:
+        raise SkipTest("G++ not available, so we need to skip this test.")
+    # Testing that duplicate inputs are allowed.
+    x, y, z = inputs()
+    e = add(x, y)
+    lnk = CLinker().accept(Env([x, y, z], [e]))
+    fn = lnk.make_function()
+    assert fn(2.0, 1.5, 1.0) == 3.5
+    # note: for now the behavior of fn(2.0, 7.0) is undefined
+
+
 def test_clinker_dups_inner():
     if not theano.config.cxx:
         raise SkipTest("G++ not available, so we need to skip this test.")