[Bug fortran/51727] Changing module files

[Joost.VandeVondele at mat dot ethz.ch]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51727

--- Comment #25 from Joost VandeVondele <Joost.VandeVondele at mat dot ethz.ch> 2012-10-15 14:14:12 UTC ---
Just to provide some additional numbers on how important this patch is for
practical development (and of course to +1 on backports).... for a 'typical
code change' on a CP2K tree (add an unused local variable to a subroutine) the
speedup due to avoided recompilation (on a 32 core server) can be obtained from
the following compile timings (repeatable for various tries):

4.6(unpatched)
real    1m45.064s

4.7(patched)
real    0m14.958s

I really think this is a pretty substantial bug fix of an existing feature.