Alloc OpRemove to accept a class to remove. Tested by test_gradien.py:test_grad_clip

theano/gof/opt.py

@@ -1542,8 +1542,10 @@ class OpRemove(LocalOptimizer):
         return [self.op]
 
     def transform(self, node):
-        if node.op != self.op:
-            return False
+        if inspect.isclass(self.op):
+            if isinstance(node.op, self.op):
+                return node.inputs
+        elif node.op == self.op:
             return node.inputs
 
     def __str__(self):

theano/tensor/opt.py

@@ -7502,11 +7502,9 @@ register_canonicalize(gof.OpRemove(theano.gradient.disconnected_grad_),
                       name='remove_disconnected_grad')
 
 
-@register_canonicalize
-@gof.local_optimizer([theano.gradient.GradClip])
-def local_grad_clip(node):
-    if isinstance(node.op, theano.gradient.GradClip):
-        return node.inputs
+register_canonicalize(gof.OpRemove(theano.gradient.GradClip),
+                      'fast_compile', 'fast_run',
+                      name='remove_grad_clip')
 
 
 @register_useless