RFR: Add missing case for CAE to ShLRB::needs_barrier_impl()

[Roman Kennke]

Am 22. Februar 2019 12:24:57 MEZ schrieb Aleksey Shipilev <shade at redhat.com>:
>On 2/22/19 12:23 PM, Roman Kennke wrote:
>> We need a case for CompareAndExchangeP|N in
>> ShenandoahLoadReferenceBarrierNode::needs_barrier_impl(), otherwise
>we
>> crash in the ShouldNotReachHere() below (in debug builds). This
>happened
>> in CI.
>> 
>> Testing: hotspot_gc_shenandoah
>> 
>> http://cr.openjdk.java.net/~rkennke/lrb-cae-2/webrev.00/
>
>But wait, how do we even get these nodes with Shenandoah enabled? Isn't
>that basically a bug
>somewhere else?

We replace the Shenandoah variants by the barrier-free variants when cmpval input is known NULL, in which case we don't need the barrier loop, and it's fairly common, too.

Roman

>-Aleksey

-- 
Diese Nachricht wurde von meinem Android-Gerät mit K-9 Mail gesendet.