Faster trivial equality checks

lib/iris/coords.py

@@ -582,6 +582,9 @@ def __repr__(self):
         return self.summary(shorten=True)
 
     def __eq__(self, other):
+        if other is self:
+            return True
+
         # Note: this method includes bounds handling code, but it only runs
         #  within Coord type instances, as only these allow bounds to be set.
 

lib/iris/cube.py

@@ -3826,6 +3826,9 @@ def _deepcopy(self, memo, data=None):
 
     # START OPERATOR OVERLOADS
     def __eq__(self, other):
+        if other is self:
+            return True
+
         result = NotImplemented
 
         if isinstance(other, Cube):

lib/iris/util.py

@@ -371,6 +371,8 @@ def array_equal(array1, array2, withnans=False):
     This function maintains laziness when called; it does not realise data.
     See more at :doc:`/userguide/real_and_lazy_data`.
     """
+    if withnans and (array1 is array2):
+        return True
 
     def normalise_array(array):
         if not is_lazy_data(array):