diff -r 78145e6ffb40 Lib/enum.py
--- a/Lib/enum.py	Wed Feb 18 08:56:33 2015 -0500
+++ b/Lib/enum.py	Fri Feb 20 01:28:10 2015 -0800
@@ -159,20 +159,24 @@ class EnumMeta(type):
             # If another member with the same value was already defined, the
             # new member becomes an alias to the existing one.
             for name, canonical_member in enum_class._member_map_.items():
                 if canonical_member._value_ == enum_member._value_:
                     enum_member = canonical_member
                     break
             else:
                 # Aliases don't appear in member names (only in __members__).
                 enum_class._member_names_.append(member_name)
             enum_class._member_map_[member_name] = enum_member
+            # performance boost for any member that would not shadow
+            # a DynamicClassAttribute
+            if not hasattr(enum_class, member_name):
+                setattr(enum_class, member_name, enum_member)
             try:
                 # This may fail if value is not hashable. We can't add the value
                 # to the map, and by-value lookups for this value will be
                 # linear.
                 enum_class._value2member_map_[value] = enum_member
             except TypeError:
                 pass
 
         # double check that repr and friends are not the mixin's or various
         # things break (such as pickle)
@@ -461,21 +465,21 @@ class Enum(metaclass=EnumMeta):
                 self.__class__.__name__, self._name_, self._value_)
 
     def __str__(self):
         return "%s.%s" % (self.__class__.__name__, self._name_)
 
     def __dir__(self):
         added_behavior = [
                 m
                 for cls in self.__class__.mro()
                 for m in cls.__dict__
-                if m[0] != '_'
+                if m[0] != '_' and m not in self._member_map_
                 ]
         return (['__class__', '__doc__', '__module__', 'name', 'value'] +
                 added_behavior)
 
     def __format__(self, format_spec):
         # mixed-in Enums should use the mixed-in type's __format__, otherwise
         # we can get strange results with the Enum name showing up instead of
         # the value
 
         # pure Enum branch