bug#23476: Slowdown in C Mode fontification [Was: bug#23476: 25.0.93; Visiting C files on master signals an error]

[Alan Mackenzie]

Hello, Eli.

On Tue, May 10, 2016 at 07:51:32AM +0000, Alan Mackenzie wrote:
> On Mon, May 09, 2016 at 10:11:14PM +0300, Eli Zaretskii wrote:

> [ .... ]

> > Btw, I noticed that CC Mode is quite a bit slower on master than it is
> > on emacs-25 (try searching for "IF_LINT" in xdisp.c), is that related
> > to these changes in any way?

> Whoops!  No, this slowdown is caused by commit
> 89d1776b81ab552192ee41f13ce84ff86bda4556 on 2016-04-25, a fix for bug
> #7918.  The bug was the spurious fontification of something like "for (;
> a * b;)".

> I'll see if I can find a better fix; if not, it would probably be best to
> remove the commit and leave the bug unfixed.

I've reverted that commit, and reopened bug #7918.  It's going to be
difficult to fix in a manner which doesn't slow down CC Mode's
fontification.  :-(

-- 
Alan Mackenzie (Nuremberg, Germany).