nnet opt - added local optimizer to merge softmax with crossentropy_softmax

theano/tensor/nnet.py

@@ -1251,6 +1251,18 @@ def local_advanced_indexing_crossentropy_onehot_grad(node):
     else:
         return
 
+@opt.register_specialize
+@gof.local_optimizer([softmax_with_bias])
+def graph_merge_softmax_with_crossentropy_softmax(node):
+    if node.op == softmax_with_bias:
+        x, b = node.inputs
+        for x_client in x.clients:
+            if x_client[0].op == crossentropy_softmax_argmax_1hot_with_bias:
+                big_client = x_client[0]
+                if big_client in [b_client[0] for b_client in b.clients]:
+                    xx, bb, ll = big_client.inputs
+                    mergeable_client = big_client.op(x, b, ll)
+                    return [mergeable_client[1]]
 
 
 def binary_crossentropy(output, target):