RFR: JDK-8221766: Load-reference barriers for Shenandoah

Vladimir Kozlov vladimir.kozlov at oracle.com
Wed Apr 3 16:45:42 UTC 2019


I don't think it should be part of this cleanup.

Please, file separate RFE to push this change with separate review and testing.

Thanks,
Vladimir

On 4/3/19 4:18 AM, Roland Westrelin wrote:
> 
> Hi Vladimir,
> 
>> opto/loopnode.cpp new is_Phi check was added. Please, explain.
> 
> When we expand barriers, if we find a null check nearby we move the
> barrier close to the null check so there's a better chance of converting
> it to an implicit null check. That happens as part of a pass of loop
> opts. I think that's where that change comes from but I don't remember
> the details. In general we need the control that's assigned to a load to
> not be too conservative.
> 
> Anyway, that change is not required for correctness. But it looks
> reasonable to me.
> 
> Roland.
> 


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