Small modif to make the output of get_canonical_form_slice() simpler<

theano/tensor/subtensor.py

@@ -100,6 +100,7 @@ def get_canonical_form_slice(theslice, length):
 
         if step is None:
             step = 1
+            is_step_constant = True
 
         # First handle the easier and common case where `step` is 1 and
         # either `start` or `stop` is a range boundary. More specializations

theano/tensor/tests/test_opt.py

@@ -2408,10 +2408,10 @@ def test_local_subtensor_of_alloc():
             for slices in slicess:
                 z = yx.__getitem__(slices)
                 f = theano.function([x], z)
-#                theano.printing.debugprint(f)
-#                if theano.config.mode != 'FAST_COMPILE':
-#                    assert not any([isinstance(node.op, Subtensor)
-#                                    for node in f.maker.fgraph.toposort()])
+                if theano.config.mode != 'FAST_COMPILE':
+                    # Subtensor can be in the input of Alloc
+                    assert not isinstance(f.maker.fgraph.toposort()[-1].op,
+                                          Subtensor)
                 val = f(xval)
                 assert xval.__getitem__(slices).shape == val.shape