anchor.diff:  
   (defmethod draw-instruction ((instruction get-arg-instruction) stream)
     (format stream "   ~a [label = \"arg\", color = orange];~%"
  -	  (gethash instruction *instruction-table*)))
  +	  (unique-id instruction)))
   
   ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   ;;;
   ;;; Instructions for low-level operators.
  -
  -;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  -;;;
  -;;; Instruction MEMALLOC-INSTRUCTION.
  -;;;
  -;;; FIXME: maybe remove this one, and replace it with a function call
  -;;; (which could be inlined).  The corresponding function would return
  -;;; a fixnum which has a magnitude that is 1/4 or 1/8 of the raw
  -;;; address, which would make it contain exactly the same bits as the
  -;;; raw address itself, provided the tag for fixnums is 0.
  -
  -(defclass memalloc-instruction (instruction)
  -  ())
  -
  -(defun make-memalloc-instruction (input output successor)
  -  (make-instance 'memalloc-instruction
  -    :inputs (list input)
  -    :outputs (list output)
  -    :successors (list successor)))
  -
  -(defmethod draw-instruction ((instruction memalloc-instruction) stream)
  -  (format stream "   ~a [label = \"memalloc\"];~%"
  -	  (gethash instruction *instruction-table*)))
   
   ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   ;;;
  
positive.code: 
  (defmethod draw-instruction ((instruction s<=-instruction) stream)
    (format stream "   ~a [label = \"s<=\"];~%"
  	  (gethash instruction *instruction-table*)))
  
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;
  
negative.code: 
  (defmethod draw-instruction ((instruction funcall-instruction) stream)
    (format stream "   ~a [label = \"funcall\"];~%"
  	  (unique-id instruction)))
  
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;
  