(defun ir1-optimize-return (node)
(declare (type creturn node))
(let* ((tails (lambda-tail-set (return-lambda node)))
(defun ir1-optimize-return (node)
(declare (type creturn node))
(let* ((tails (lambda-tail-set (return-lambda node)))
;;; changes. We look at each changed argument. If the corresponding
;;; variable is set, then we call PROPAGATE-FROM-SETS. Otherwise, we
;;; consider substituting for the variable, and also propagate
;;; changes. We look at each changed argument. If the corresponding
;;; variable is set, then we call PROPAGATE-FROM-SETS. Otherwise, we
;;; consider substituting for the variable, and also propagate
;;;
;;; Substitution is inhibited when the arg leaf's derived type isn't a
;;; subtype of the argument's asserted type. This prevents type
;;;
;;; Substitution is inhibited when the arg leaf's derived type isn't a
;;; subtype of the argument's asserted type. This prevents type
;;; are done, then we delete the LET.
;;;
;;; Note that we are responsible for clearing the
;;; are done, then we delete the LET.
;;;
;;; Note that we are responsible for clearing the
(defun propagate-let-args (call fun)
(declare (type combination call) (type clambda fun))
(loop for arg in (combination-args call)
(defun propagate-let-args (call fun)
(declare (type combination call) (type clambda fun))
(loop for arg in (combination-args call)
(lambda-optional-dispatch fun))
(let* ((vars (lambda-vars fun))
(union (mapcar #'(lambda (arg var)
(lambda-optional-dispatch fun))
(let* ((vars (lambda-vars fun))
(union (mapcar #'(lambda (arg var)