Still merge identical Asserts while Assert merging is disabled.

theano/gof/opt.py

@@ -615,6 +615,7 @@ class MergeFeature(object):
 
             # Put all clients of Assert inputs (if exist) into merge_candidates
             # TODO: Deactivated for now as this cause cycle in the graph.
+            # (There is a second deactivation part below.)
             for i in []:  # node.inputs:
                 if i.owner and isinstance(i.owner.op,
                                           theano.tensor.opt.Assert):
@@ -647,7 +648,8 @@ class MergeFeature(object):
 
             # Get input list of the candidate with assert removed
             cand_inputs_assert_removed = []
-            for i in candidate.inputs:
+            # TODO: Deactivated while Assert merging is disabled. (See above and below.)
+            for i in []:  # candidate.inputs:
                 if i.owner and isinstance(i.owner.op,
                                           theano.tensor.opt.Assert):
                     cand_has_assert = True
@@ -655,6 +657,11 @@ class MergeFeature(object):
                 else:
                     cand_inputs_assert_removed.append(i)
 
+            # TODO: Remove this when Assert merging is re-enabled. (See above.)
+            # Without Assert merging we can still look for identical Asserts,
+            # so we should not treat Asserts separately for now.
+            cand_inputs_assert_removed = candidate.inputs
+
             # Get input list of the node with assert removed
             if node_has_assert:
                 node_inputs_assert_removed = []

theano/gof/tests/test_opt.py

@@ -399,6 +399,30 @@ class TestMergeOptimizer:
 '''
         assert strg == strref, (strg, strref)
 
+    def test_both_assert_merge_identical(self):
+        # Merge two nodes, both have assert on the same node
+        # with the same conditions.
+        x1 = T.matrix('x1')
+        x2 = T.matrix('x2')
+        e = T.dot(T.opt.assert_op(x1, (x1 > x2).all()), x2) +\
+            T.dot(T.opt.assert_op(x1, (x1 > x2).all()), x2)
+        g = FunctionGraph([x1, x2], [e])
+        MergeOptimizer().optimize(g)
+        strg = theano.printing.debugprint(g, file='str')
+        strref = '''Elemwise{add,no_inplace} [id A] ''   4
+ |dot [id B] ''   3
+ | |Assert{msg='Theano Assert failed!'} [id C] ''   2
+ | | |x1 [id D]
+ | | |All [id E] ''   1
+ | |   |Elemwise{gt,no_inplace} [id F] ''   0
+ | |     |x1 [id D]
+ | |     |x2 [id G]
+ | |x2 [id G]
+ |dot [id B] ''   3
+'''
+        # print(strg)
+        assert strg == strref, (strg, strref)
+
     def est_both_assert_merge_1(self):
         # Merge two nodes, both have assert on the same node
         # with different conditions.