anchor.diff:  
   ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
   ;;;
  -;;; Compile a FIXNUM-+-AST.
  +;;; Compile a FIXNUM-ADD-AST.
   
  -(defmethod compile-ast ((ast cleavir-ast:fixnum-+-ast) context)
  +(defmethod compile-ast ((ast cleavir-ast:fixnum-add-ast) context)
     (with-accessors ((results results)
   		   (successors successors))
         context
       (unless (and (= (length results) 1)
   		 (= (length successors) 2))
  -      (error "Invalid context for FIXNUM-+-AST."))
  +      (error "Invalid context for FIXNUM-ADD-AST."))
       (let ((temp1 (make-temp nil))
   	  (temp2 (make-temp nil))
   	  (result (find-or-create-location (cleavir-ast:variable-ast ast))))
  
positive.code: 		(list (compile-ast
  		       (cleavir-ast:arg2-ast ast)
  		       (context (list temp2)
  				(cleavir-mir:make-fixnum-=-instruction
  				 (list temp2 temp1)
  				 successors)))))))))
  
negative.code: 		(list (compile-ast
  		       (cleavir-ast:arg2-ast ast)
  		       (context (list temp2)
  				(cleavir-mir:make-fixnum-not-greater-instruction
  				 (list temp1 temp2)
  				 successors)))))))))
  
  ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
  ;;;
  ;;; Compile a FIXNUM-GREATER-AST.
  
  (defmethod compile-ast ((ast cleavir-ast:fixnum-greater-ast) context)
    (with-accessors ((results results)
  		   (successors successors))
        context
      (unless (and (null results)
  		 (= (length successors) 2))
        (error "Invalid context for FIXNUM-GREATER-AST."))
      (let ((temp1 (make-temp nil))
  	  (temp2 (make-temp nil)))
        (compile-ast
  