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

[Eli Zaretskii]

> From: Ihor Radchenko <yantar92@posteo.net>
> Cc: larsi@gnus.org, monnier@iro.umontreal.ca, 58558@debbugs.gnu.org
> Date: Tue, 13 Dec 2022 18:03:49 +0000
> 
> > Calling xbacktrace will show a Lisp backtrace, which could be
> > educational here.
> 
> (gdb) xbacktrace
> Undefined command: "xbacktrace".  Try "help".
> 
> I am not sure what you mean by xbacktrace.

It's a command we define in src/.gdbinit.  Try this:

  (gdb) source /path/to/emacs/src/.gdbinit
  (gdb) xbacktrace

But do that after catching Fmake_marker call from Fmatch_data, like
you did before.