Add an UnShapeOp opt that remove the shape feature. To enable optimizer_including=UnShapeOpt

theano/tensor/opt.py

@@ -1408,19 +1408,28 @@ class ShapeFeature(object):
 
 class ShapeOptimizer(Optimizer):
     """Optimizer that serves to add ShapeFeature as an fgraph feature."""
-    def __init__(self):
-        Optimizer.__init__(self)
-
     def add_requirements(self, fgraph):
         fgraph.attach_feature(ShapeFeature())
 
     def apply(self, fgraph):
         pass
 
+class UnShapeOptimizer(Optimizer):
+    """Optimizer remove ShapeFeature as an fgraph feature."""
+    def apply(self, fgraph):
+        for feature in fgraph._features:
+            if isinstance(feature, ShapeFeature):
+                fgraph.remove_feature(feature)
+
 # Register it after merge1 optimization at 0. We don't want to track
 # the shape of merged node.
 theano.compile.mode.optdb.register('ShapeOpt', ShapeOptimizer(),
                                    0.1, 'fast_run', 'fast_compile')
+# Not enabled by default for now. Some crossentropy opt use the
+# shape_feature.  They are at step 2.01. uncanonicalize is at step
+# 3. After it goes to 48.5 that move to the gpu. So 10 seem resonable.
+theano.compile.mode.optdb.register('UnShapeOpt', UnShapeOptimizer(),
+                                   10)
 
 
 def local_elemwise_alloc_op(ElemwiseOP, AllocOP, DimShuffleOP):