let convert_binop = function
    CTTbinTimes        -> PbinTimes       
  | CTTbinDiv          -> PbinDiv         
  | CTTbinPlusVV       -> PbinPlus
  | CTTbinMinusVV      -> PbinMinus
  | CTTbinPostPlusVV   -> assert false
  | CTTbinPostMinusVV  -> assert false
  | CTTbinPlusPV       -> PbinPlus 
  | CTTbinMinusPP      -> PbinMinus
  | CTTbinMinusPV      -> PbinMinus
  | CTTbinPostPlusPV   -> assert false
  | CTTbinPostMinusPV  -> assert false
  | CTTbinModulo       -> PbinModulo      
  | CTTbinLshift       -> PbinLshift      
  | CTTbinRshift       -> PbinRshift      
  | CTTbinLogAnd       -> PbinLogAnd
  | CTTbinLogOr        -> PbinLogOr
  | CTTbinIntAnd       -> PbinIntAnd      
  | CTTbinIntOr        -> PbinIntOr       
  | CTTbinIntXor       -> PbinIntXor      
  | CTTbinLessThan     -> PbinLessThan    
  | CTTbinLessEqual    -> PbinLessEqual   
  | CTTbinGtrThan      -> PbinGtrThan     
  | CTTbinGtrEqual     -> PbinGtrEqual    
  | CTTbinEqual        -> PbinEqual       
  | CTTbinNotEqual     -> PbinNotEqual