RFR(S): 8241675: Shenandoah: assert(n->outcnt() > 0) at shenandoahSupport.cpp:2858 with java/util/Collections/FindSubList.java

[Roman Kennke]

Ok. Thank you!

Roman

> 
> http://cr.openjdk.java.net/~roland/8241675/webrev.00/
> 
> When the LRB is expanded, raw memory around the barrier has to be
> correctly rewired. for this to happen regions that can be reached from
> the point where the barrier is expanded must have a raw memory
> Phi. There are cases where the new Phis will prove useless and optimize
> out. Current code has logic to not create Phis where they are expected
> to optimize out. This is done to save on compile time. That logic is
> broken and skips a region that shouldn't be skipped (an early exit from
> a loop). Rather than try to fix it, I propose dropping most of it. I ran
> specjvm2008 and looked at compile time with and without it and it
> doesn't seem to be affected or at least not in a way that appears to be
> significant compared to the overall compile time.
> 
> Roland.
>