Use of vector instructions in memmov/memset expanding

[Jan Hubicka]

> > Do you know glibc version numbers when
> > the optimized string functions was introduced?
> 
> Afaik, it's 2.13.
> I also compared my implementation to 2.13.

I wonder if we can assume that most of GCC 4.7 based systems will be glibc 2.13
based, too.  I would tend to say that yes and thus would suggest to tamn down
inlining that is no longer profitable on newer glibcs with a note in
changes.html...

(I worry about the tables in i386.c deciding what strategy to use for block of
given size. This is more or less unrelated to the actual patch)

Honza