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Strength-reduce apply with (list ...) as tail argument

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* lisp/emacs-lisp/byte-opt.el (byte-optimize-apply):
Transform (apply F ... (list X ...)) -> (funcall F ... X ...)
This commit is contained in:
Mattias Engdegård 2022-08-12 15:04:51 +02:00
parent e99d7c4d62
commit 1d8712bcc9
1 changed files with 19 additions and 18 deletions
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37
lisp/emacs-lisp/byte-opt.el
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@ -1207,25 +1207,26 @@ See Info node `(elisp) Integer Basics'."
form)))
(defun byte-optimize-apply (form)
;; If the last arg is a literal constant, turn this into a funcall.
;; The funcall optimizer can then transform (funcall 'foo ...) -> (foo ...).
(if (= (length form) 2)
;; single-argument `apply' is not worth optimizing (bug#40968)
form
(let ((fn (nth 1 form))
(last (nth (1- (length form)) form))) ; I think this really is fastest
(or (if (or (null last)
(eq (car-safe last) 'quote))
(if (listp (nth 1 last))
(let ((butlast (nreverse (cdr (reverse (cdr (cdr form)))))))
(nconc (list 'funcall fn) butlast
(mapcar (lambda (x) (list 'quote x)) (nth 1 last))))
(let ((len (length form)))
(if (>= len 2)
(let ((fn (nth 1 form))
(last (nth (1- len) form)))
(cond
;; (apply F ... '(X Y ...)) -> (funcall F ... 'X 'Y ...)
((or (null last)
(eq (car-safe last) 'quote))
(let ((last-value (nth 1 last)))
(if (listp last-value)
`(funcall ,fn ,@(butlast (cddr form))
,@(mapcar (lambda (x) (list 'quote x)) last-value))
(byte-compile-warn-x
last
"last arg to apply can't be a literal atom: `%s'"
last)
nil))
form))))
last "last arg to apply can't be a literal atom: `%s'" last)
nil)))
;; (apply F ... (list X Y ...)) -> (funcall F ... X Y ...)
((eq (car-safe last) 'list)
`(funcall ,fn ,@(butlast (cddr form)) ,@(cdr last)))
(t form)))
form)))
(put 'funcall 'byte-optimizer #'byte-optimize-funcall)
(put 'apply 'byte-optimizer #'byte-optimize-apply)