missing memory barrier in acmp with C2

[Roman Kennke]

Am Mittwoch, den 26.10.2016, 13:24 +0200 schrieb Roland Westrelin:
> http://cr.openjdk.java.net/~roland/shenandoah/membar-acmp/webrev.00/
> 
> The code generated for acmp is missing a memory barrier.

Great!

> Should it be a loadstore + loadload as in
> ShenandoahBarrierSet::asm_acmp_barrier() on aarch64 or simply a
> loadload?

I can come up with a reason for loadload, but not for loadstore, I
think loadstore is not necessary there. I'd go for the less restrictive
fence unless we come up with a good reason not to.

Roman