anchor.diff:  	  ; Remove code after label until next tag.
   	  ((and (consp a)
   			(eq 'vm-go a.))
  -		 (cons a (opt-peephole-remove-void (opt-peephole-find-next-tag d))))
  -
  -	  ; Shorten (%setq expexsym sth) (%setq sth expexsym).
  -	  ((and (%setq? a) (%setq? d.)
  -	        (expex-sym? .a.)
  -		    (eq .a. (third d.)))
  -	     (cons `(%setq ,(second d.) ,..a.)
  -			   (opt-peephole-remove-void .d)))))
  +		 (cons a (opt-peephole-remove-void (opt-peephole-find-next-tag d))))))
   
   (defun opt-peephole-will-be-set-again? (x v)
     (if x
  
positive.code: 					             x))
  					   (funcall
  						 (compose ;#'reduce-tags
  								  #'remove-code
  								  #'opt-peephole-remove-void)
  						 x))))
  
  
negative.code: 
        ; Remove second of (setf x y y x).
  	  ((and (%setq? a)
  			(%setq? d.)
  			(eq .a. (third d.))
  			(eq (second d.) ..a.))
  