RFR(M): 8209420: Track membars for volatile accesses so they can be properly optimized

[Andrew Dinn]

On 14/08/18 09:20, Roland Westrelin wrote:
> Thanks for looking at this.
> 
>> I think we need to be consistent about how we handle these operations.
> 
> Covering all volatile operations would have to be done as a separate
> change, right?
If this is needed then I think that makes sense.

Note that the existing transformation only applies to volatile reads and
writes and CASes and Roland's proposed patch merely re-implements the
status quo. Up to now all other operations requiring barriers, i.e.
unsafe putXXXRelease, getXXXAcquire, getAndIncrement etc, have relied on
a combination of dmb ish and/or dmb ishld instructions being planted
adjacent to or bracketing the associated load/store instructions.

regards,


Andrew Dinn
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