--- a/python/ir/instruction.py	Sun Aug 04 18:34:06 2013 +0200
+++ b/python/ir/instruction.py	Mon Aug 05 19:46:11 2013 +0200
@@ -32,6 +32,9 @@
                 return False
         return True
 
+    def lastUse(self, ins):
+        assert ins in self.used_by
+        return all(not ins.precedes(ub) for ub in self.used_by)
 
 class Variable(Value):
     pass
@@ -97,7 +100,13 @@
 
     @property
     def Position(self):
-        return self.parent.Instructions.index(self)
+        return self.Block.Instructions.index(self)
+
+    def precedes(self, other):
+        assert isinstance(other, Instruction)
+        if self.Block is other.Block:
+            return other.Position > self.Position
+        return self.Block.precedes(other.Block)
 
     @property
     def Function(self):