bug#58558: 29.0.50; re-search-forward is slow in some buffers

[Ihor Radchenko]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> If you switch the buffer to `clean-mode' (which should remove all text
> props), does the slowdown disappear?  In that case, it seems likely that
> the slowdown is connected to text properties, somehow.

The slowdown becomes slightly better, but nowhere close to Emacs 28:

;; Emacs 29
;; Elapsed time: 16.953404s
;; Emacs 29 + clean-mode
;; Elapsed time: 13.290568s
;; Emacs 28
;; Elapsed time: 0.869748s

I did

(setq yant/re "\\(?:\\(?:\\<DEADLINE: 
*\\(\\(?:<\\(?:[[:digit:]]\\{4\\}-[[:digit:]]\\{2\\}-[[:digit:]]\\{2\\}\\(?: 
[[:alpha:]]+\\)?\\)\\(?: 
[[:digit:]]\\{1,2\\}:[[:digit:]]\\{2\\}\\(?:-[[:digit:]]\\{1,2\\}:[[:digit:]]\\{2\\}\\)?\\)?\\(?:\\(?:
 
[+.:-]\\{1,2\\}[[:digit:]]+[dhmwy]\\(?:/[[:digit:]]+[dhmwy]\\)?\\)\\{1,2\\}\\)?>\\)\\)\\)\\|\\(?:\\(?:<\\(?:[[:digit:]]\\{4\\}-[[:digit:]]\\{2\\}-[[:digit:]]\\{2\\}\\(?:
 [[:alpha:]]+\\)?\\)\\(?: 
[[:digit:]]\\{1,2\\}:[[:digit:]]\\{2\\}\\(?:-[[:digit:]]\\{1,2\\}:[[:digit:]]\\{2\\}\\)?\\)?\\(?:\\(?:
 
[+.:-]\\{1,2\\}[[:digit:]]+[dhmwy]\\(?:/[[:digit:]]+[dhmwy]\\)?\\)\\{1,2\\}\\)?>\\)\\|^\\*+[[:blank:]]+\\(?:[[:upper:]]+[[:blank:]]+\\)?\\[#A]\\|^[[:space:]]*:STYLE:[[:space:]]+habit[[:space:]]*$\\)\\)")
(benchmark-progn (goto-char (point-min)) (while (re-search-forward yant/re nil 
t)))

-- 
Ihor Radchenko // yantar92,
Org mode contributor,
Learn more about Org mode at <https://orgmode.org/>.
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