More utility code caching.

Cython/Compiler/Code.py

@@ -318,6 +318,8 @@ class ContentHashingUtilityCode(UtilityCode):
         return hash((self.proto, self.impl))
 
     def __eq__(self, other):
+        if self is other:
+            return True
         if not isinstance(other, type(self)):
             return False
 

Cython/Compiler/Optimize.py

@@ -32,8 +32,11 @@ try:
 except ImportError:
     basestring = str # Python 3
 
+_utility_cache = {}
 def load_c_utility(name):
-    return ContentHashingUtilityCode.load(name, "Optimize.c")
+    if name not in _utility_cache:
+      _utility_cache[name] = ContentHashingUtilityCode.load(name, "Optimize.c")
+    return _utility_cache[name]
 
 class FakePythonEnv(object):
     "A fake environment for creating type test nodes etc."