bug#56682: Fix the long lines font locking related slowdowns

[Dmitry Gutov]

On 15.08.2022 17:06, Eli Zaretskii wrote:
> > Date: Sun, 14 Aug 2022 23:46:13 +0300
> > Cc: 56682@debbugs.gnu.org, gregory@heytings.org, monnier@iro.umontreal.ca
> > From: Dmitry Gutov <dgutov@yandex.ru>
> >
> > I've also run this test on master now, and M-> is not instant there
> > either.
>
> It's instantaneous here, so I'm not sure why you see something
> different.

No idea. Size of file, or even the contents might the reason.

Here's the profiler output anyway:

        1067  85% - command-execute
        1067  85%  - call-interactively
        1023  82%   - funcall-interactively
        1012  81%    - end-of-buffer
        1008  81%     - recenter
        1008  81%      - jit-lock-function
        1008  81%       - jit-lock-fontify-now
        1008  81%        - jit-lock--run-functions
        1008  81%         - run-hook-wrapped
        1008  81%          - #<compiled -0x149e7c2f08a063c3>
        1008  81%           - font-lock-fontify-region
        1008  81%            - font-lock-default-fontify-region
        1008  81%             - nxml-extend-region
         720  57%              - skip-syntax-forward
         720  57%               - internal--syntax-propertize
         720  57%                - syntax-propertize
         720  57%                 - nxml-syntax-propertize
         720  57%                  - sgml-syntax-propertize
         378  30%                     #<compiled -0x12505696cac83570>
         294  23%                     sgml--syntax-propertize-ppss
         288  23%              - nxml-move-outside-backwards
         288  23%               - nxml-inside-start
         288  23%                  syntax-ppss
          11   0%    + execute-extended-command
          44   3%   + byte-code
         171  13% - ...
         171  13%    Automatic GC
           5   0% + timer-event-handler