scan_pushout_seq : avoid removing computation unrelated to sequences

theano/scan_module/scan_opt.py

@@ -426,15 +426,19 @@ class PushOutSeqScan(gof.Optimizer):
                     not nd in to_remove):
                     to_remove.append(nd)
                     outside_ins = []
+                    depends_on_seqs = False
+
                     for x in nd.inputs:
                         if x in inner_non_seqs:
                             _idx = inner_non_seqs.index(x)
                             outside_ins += [outer_non_seqs[_idx]]
                         elif x in inner_seqs:
                             outside_ins += [outer_seqs[inner_seqs.index(x)]]
+                            depends_on_seqs = True
                         elif x in to_replace:
                             outside_ins += [replace_with_out[
                                 to_replace.index(x)]]
+                            depends_on_seqs = True
                         elif isinstance(x, theano.Constant):
                             outside_ins += [x.clone()]
                         else:
@@ -444,6 +448,15 @@ class PushOutSeqScan(gof.Optimizer):
                                  'to move some computation fron scan '
                                  'which is not allowed to move. Report '
                                  'this on theano-users list'), x)
+
+                    if not depends_on_seqs:
+                        # Removing this node from the inner graph of scan
+                        # should be handled by the PushOutNonSeqScan
+                        # optimization. The current optimization only tries
+                        # to pull sequence-dependant computation out of
+                        # scan.
+                        continue
+
                     # Do not call make_node for test_value
                     nw_outer_node = nd.op(*outside_ins,
                                           **dict(return_list=True))[0].owner