bug#45379: 28.0.50; Degraded Performance of describe-buffer-bindings

[Stefan Kangas]

tags 45379 + patch
thanks

Stefan Kangas <stefan@marxist.se> writes:

> "Sheng Yang" <styang@fastmail.com> writes:
>
>> Hi Juri,
>>
>> I recently came across a regression of performance in Emacs for
>> describe bindings, which I have reported as bug#45379. After
>> bisection, the offending seems to be a commit a649034336 you pushed in
>> November 2020, to fix bug#5423. [...]
>>
>> a649034336 * bad Don't show key ranges if shadowed by different commands
>
> BTW, the offending commit is not Juri's.  It is mine:
>
>     Author: Stefan Kangas <stefan@marxist.se>
>     Date:   Fri Nov 13 15:28:29 2020 +0100
>
>         Don't show key ranges if shadowed by different commands

Please try the attached patch and see that it fixes this performance
regression.

It turns out that we were doing unnecessary looping due to the above
mentioned commit.  While working on this, I also found that we can get
rid of an unnecessary call to char_table_ref_and_range, which should
make this function run even faster.

I'm also copying in Kenichi Handa, who was the last to touch this code.
Handa-san, please let us know if you have any comments on this patch.
Thanks in advance.

0001-Fix-describe-buffer-bindings-performance-regression.patch
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