bug#21028: Performance regression in revision af1a69f4d17a482c359d98c00ef86fac835b5fac (Apr 2014).

[Eli Zaretskii]

> Date: Fri, 10 Jul 2015 03:34:23 -0700
> From: Clément Pit--Claudel <clement.pitclaudel@live.com>
> 
> I tried to pinpoint the commit that introduced the bug, and found revision 
> af1a69f4d17a482c359d98c00ef86fac835b5fac by bisecting between 24.3 and 
> master. Here's the commit in question:
> 
>   af1a69f4d17a482c359d98c00ef86fac835b5fac is the first bad commit
>   commit af1a69f4d17a482c359d98c00ef86fac835b5fac
>   Author: Dmitry Antipov <dmantipov@yandex.ru>
>   Date:   Wed Apr 2 17:24:19 2014 +0400
> 
>       * font.c (font_list_entities): Do not add empty vector to font cache.
>       (font_matching_entity): Likewise.  If matching entity is found, insert
>       1-item vector with this entity instead of entity itself (Bug#17125).

Maybe I'm blind, but I don't see anything in that changeset that could
explain a performance hit.  The modified code seems to do
approximately the same amount of work, and create the same data
structures, as the original one.  Are you sure that backing out those
changes fixes your problem?