RFR (11): Revert MachMemBarNode related diffs vs. upstream

[Aleksey Shipilev]

On 5/29/19 4:43 PM, Roman Kennke wrote:
> Back when we had membars in our barriers (acmp I think), we needed some
> extra fluff to deal with those. We can revert this in 11 now:
> http://cr.openjdk.java.net/~rkennke/jdk11-revert-machmembarnode/webrev.00/
> 
> This is mostly a reversal of the upstream change (>11):
> http://hg.openjdk.java.net/jdk/jdk/rev/904cf5407ac7
Yes, the reversal looks good.

Thanks,
-Aleksey