[8u] RFR: 8221355: Performance regression after JDK-8155635 backport into 8u

[Aleksey Shipilev]

On 4/10/19 2:42 PM, Severin Gehwolf wrote:
> Is there a reason to keep unused local variable 'can_access_non_heap'
> around in JDK 8? It makes sense for the JDK 9 change as its being used
> further down in the same function:
> http://hg.openjdk.java.net/jdk-updates/jdk9u/hotspot/file/22d7a88dbe78/src/share/vm/opto/library_call.cpp#l2493
> 
> That's not the case for JDK 8u, though. Thoughts?

Right. I don't think there is a reason to keep the can_access_non_heap.

> The left over comment is misleading, though, which I've now removed:
> http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8221355/02/webrev/

...but now I am confused how that patch is supposed to work. It seems to me it accepts the accesses
to off-heap when object passed it is actually null, but not transparently-null for the compiler?
That is probably acceptable, but maybe someone savvy in this code can take a look? Vladimir I, Roland?

-- 
Thanks,
-Aleksey


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