Performance issue when fontifing in compile-mode.

[Oleksandr Gavenko]

I use in log file:

-*- mode: compilation-minor; mode: auto-revert-tail; default-directory: 
"~/devel" -*-

This allow easy and fast go to place where logger function make output 
(in GNU format).

But  logs with >2000 lines take 2-20 sec  on parsing after revert.

I check 'compilation-error-regexp-alist'. It contain pattern in 
alphabetical order!
(like come from 'compilation-error-regexp-alist-alist' ??)

Most of my software produce in 'gnu' format.

As I understand patterns checked in order like in 
'compilation-error-regexp-alist'.

And if string is not match any pattern all pattern in 
'compilation-error-regexp-alist'
used!

I check  which pattern in effect by:

(mapc
 (lambda (item)
   (when (string-match (elt item 1) "  [echo] file.c:45: error gg")
     (message "%s" (elt item 0))
     ))
   compilation-error-regexp-alist-alist
   )

Also I temporary put this code to .emacs:

(mapc
 (lambda (item)
   (when (memq item compilation-error-regexp-alist)
     (setq compilation-error-regexp-alist
           (cons item (assq-delete-all item 
compilation-error-regexp-alist)) )
     ))
 ;; Most latest firstly used.
 '(ant gnu)
 )

I try something like:

(setq compilation-error-regexp-alist '(gnu))

and still get same performance (slow).

When I set

(setq compilation-error-regexp-alist nil)

it match faster parse file!

So I try rewrite this regex (add my-gnu pattern before gnu).

(add-to-list 'compilation-error-regexp-alist-alist '(my-gnu 
"^\\([^:]+\\):\\([[:digit:]]+\\):" 1 2))
(add-to-list 'compilation-error-regexp-alist 'my-gnu)

It is about 2 time faster then my slow case.

With '(setq compilation-error-regexp-alist nil)' I still get blue text 
in start of string before ':'.
Who make this?