RFC (S) 8140483: Atomic*FieldUpdaters final fields should be trusted

Aleksey Shipilev aleksey.shipilev at oracle.com
Tue Oct 27 00:04:08 UTC 2015

On 10/27/2015 02:52 AM, Vitaly Davidovich wrote:
> In this particular case, A*FU is doing obj.getClass() == tclass as a
> cheaper check than what fullCheck() does, which is
> tclass.isInstance(obj).  However, theoretically speaking, if A*FU op is
> inlined into an instance method where `this` is passed, it should be
> able to determine at JIT time whether `this` is tclass or subtype of
> it.  Then that whole type check could be removed.

Yes, I get that. It may be profitable to check Class.isInstance, instead
of the exact match, so that subclasses are also acceptable. And it
indeed does help to eliminate the type check.


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