From: Mattias Engdegård Date: Sat, 11 Dec 2021 21:11:08 +0000 (+0100) Subject: Constant-propagate access to captured variables X-Git-Tag: emacs-29.0.90~3600^2~2 X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=8716f21d94bfda0072843e087833fedb38dcf13e;p=emacs.git Constant-propagate access to captured variables * lisp/emacs-lisp/byte-opt.el (byte-optimize--substitutable-p): Treat (internal-get-closed-var N) as constants for propagation purposes, because that is effectively what such forms will be compiled to. This allows for the elimination of some lexical variables. * test/lisp/emacs-lisp/bytecomp-tests.el (bytecomp-tests--test-cases): Add test case. --- diff --git a/lisp/emacs-lisp/byte-opt.el b/lisp/emacs-lisp/byte-opt.el index f6db803b78e..2bdf1f55111 100644 --- a/lisp/emacs-lisp/byte-opt.el +++ b/lisp/emacs-lisp/byte-opt.el @@ -342,8 +342,12 @@ for speeding up processing.") (numberp expr) (stringp expr) (and (consp expr) - (memq (car expr) '(quote function)) - (symbolp (cadr expr))) + (or (and (memq (car expr) '(quote function)) + (symbolp (cadr expr))) + ;; (internal-get-closed-var N) can be considered constant for + ;; const-prop purposes. + (and (eq (car expr) 'internal-get-closed-var) + (integerp (cadr expr))))) (keywordp expr))) (defmacro byte-optimize--pcase (exp &rest cases) diff --git a/test/lisp/emacs-lisp/bytecomp-tests.el b/test/lisp/emacs-lisp/bytecomp-tests.el index 7e51f820b70..a442eb473be 100644 --- a/test/lisp/emacs-lisp/bytecomp-tests.el +++ b/test/lisp/emacs-lisp/bytecomp-tests.el @@ -686,6 +686,12 @@ inner loops respectively." (let* ((x 'a)) (list x (funcall g) (funcall h))))))) (funcall (funcall f 'b))) + + ;; Test constant-propagation of access to captured variables. + (let* ((x 2) + (f (lambda () + (let ((y x)) (list y 3 y))))) + (funcall f)) ) "List of expressions for cross-testing interpreted and compiled code.")