I'm also having trouble with some cpp files. 

I've got one file
(572 lines, 18560 bytes), that always causes emacs 24 to hang. Emacs
23.3.1 handles this file just fine. 

I am using emacs from git:


commit 6ba3ea4d2625fac8b5fb839f11eeb074d699687e
Author: Christopher
Schmidt <christopher@ch.ristopher.com>
Date: Mon Mar 12 01:31:44 2012
+0800

 * ibuffer.el (ibuffer-redisplay): Remove gratuitous error.


When GDB was hanging I stopped the process with GDB, with this
backtrace: 

http://pastebin.com/ssB96ue4 

I'm not familiar with the
emacs source code, but I do not know this is normal. 

If I can help
investigation the problem more in detail, let me know. 

Unfortunately I
am not allowed to share the source file with you. 

Also I've tried to
decrease font-lock-maximum-decoration to 1, but this didn't have effect.