--- a/python/transform.py	Fri Apr 19 12:42:21 2013 +0200
+++ b/python/transform.py	Fri Apr 19 19:22:52 2013 +0200
@@ -20,7 +20,7 @@
       
 class InstructionPass(BasicBlockPass):
    def onBasicBlock(self, bb):
-      for ins in bb.Instructions:
+      for ins in iter(bb.Instructions):
          self.onInstruction(ins)
    def onInstruction(self, ins):
       """ Override this virtual method """
@@ -50,9 +50,15 @@
                print(i2)
                i.Parent.replaceInstruction(i, i2)
 
-class DeadCodeDeleter(InstructionPass):
-   def onInstruction(self, ins):
-      print(ins, ins.Users)
-      if not ins.defs in ins.live_out:
-         ins.Parent.removeInstruction(ins)
+class DeadCodeDeleter(BasicBlockPass):
+   def onBasicBlock(self, bb):
+      def instructionUsed(ins):
+         if len(ins.defs) == 0:
+            # In case this instruction does not define any variables, assume it is usefull.
+            return True
+         for d in ins.defs:
+            if d.IsUsed:
+               return True
+         return False
+      bb.Instructions = list(filter(instructionUsed, bb.Instructions))