bug#25706: 26.0.50; Slow C file fontification

[Mattias Engdegård]

4 dec. 2020 kl. 22.04 skrev Alan Mackenzie <acm@muc.de>:

> I think you'll like my latest provisional patch!
> 
> I've tracked down and eliminated a ~0.5s delay when typing characters
> into a "monster" buffer near the end.

That's nice, thank you! It seems to be about 19 % faster than the previous 
patch on this particular file, which is not bad at all.

Somehow, the delay when inserting a newline (pressing return) at line 83610 of 
osprey_reg_map_macro.h becomes longer with the patch. Of course this is more 
than compensated by the speed-up in general, but it may be worth taking a look 
at.

There is also a new and noticeable delay (0.5-1 s) in the very beginning when 
scrolling through the file. (This is with the frame sized to show 41 lines of 
80 chars of a window, excluding mode line and echo area.)