move loop invariant write barrier before loop during loop opts

[Roman Kennke]

Ok!

Roman

Am Montag, den 12.09.2016, 18:04 +0200 schrieb Roland Westrelin:
> http://cr.openjdk.java.net/~roland/shenandoah/wb-before-loops/webrev/
> 
> This moves a write barrier that operates on a value that is loop
> invariant but is kept in a loop because of memory edges before the
> loop
> during loop optimizations. This should allow further optimizations.
> 
> Roland.