From fb98c4a4060ee756af41dee7a23472219314d37a Mon Sep 17 00:00:00 2001
From: =?utf8?q?Mattias=20Engdeg=C3=A5rd?= <mattiase@acm.org>
Date: Tue, 16 Aug 2022 19:03:46 +0200
Subject: [PATCH] Improved `null` (alias `not`) optimisation
Take static boolean information of the argument into account.
* lisp/emacs-lisp/byte-opt.el (byte-optimize-not): New.
---
lisp/emacs-lisp/byte-opt.el | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/lisp/emacs-lisp/byte-opt.el b/lisp/emacs-lisp/byte-opt.el
index 74a6523cecb..bbe8135f04a 100644
--- a/lisp/emacs-lisp/byte-opt.el
+++ b/lisp/emacs-lisp/byte-opt.el
@@ -1306,11 +1306,22 @@ See Info node `(elisp) Integer Basics'."
condition
form)))
+(defun byte-optimize-not (form)
+ (and (= (length form) 2)
+ (let ((arg (nth 1 form)))
+ (cond ((null arg) t)
+ ((macroexp-const-p arg) nil)
+ ((byte-compile-nilconstp arg) `(progn ,arg t))
+ ((byte-compile-trueconstp arg) `(progn ,arg nil))
+ (t form)))))
+
(put 'and 'byte-optimizer #'byte-optimize-and)
(put 'or 'byte-optimizer #'byte-optimize-or)
(put 'cond 'byte-optimizer #'byte-optimize-cond)
(put 'if 'byte-optimizer #'byte-optimize-if)
(put 'while 'byte-optimizer #'byte-optimize-while)
+(put 'not 'byte-optimizer #'byte-optimize-not)
+(put 'null 'byte-optimizer #'byte-optimize-not)
;; byte-compile-negation-optimizer lives in bytecomp.el
(put '/= 'byte-optimizer #'byte-compile-negation-optimizer)
--
2.39.5