vim is very very slow to open and modify lilypond files

[Frédéric Bron]

Some months ago, vim became very very slow to open a lilypond file
(4-5 seconds). This is clearly due to syntax highlighting because when
turn it off (:syntax off) the files are opened instantaneously. Also
when I add an opening {, it takes a long time (1 second or more) to
update the file which is very annoying.

I looked at the 'vim' directory in the source and saw that the only
modification in the last year is very minor (commit 24e1aa563,
1/1/2014). Other modifications date to 2011. Is there any other
locations where I should look for vim files?

Has anyone else the same issue?

I am using lilypond and vim 7.4.475 on linux fedora 20.

Kind regards,

Frédéric