RFR(S): 8217990: C2 UseOptoBiasInlining: load of markword optimized to 0 if running with -XX:-EliminateLocks

Roland Westrelin rwestrel at redhat.com
Thu Feb 7 16:00:50 UTC 2019

Hi Richard,

> I noticed that the markword load is still pinned. Is this necessary?

I suspect it's not but I went with the most conservative fix.

> I guess so, because without pinning it could possibly be scheduled
> before a safepoint as it loads from a known instance which does not
> interfere memory wise with the safepoint. Or in other words: if the
> safepoint is a call, the load does not depend on the memory state
> produced by the call, because it refers to a known instance which is
> not passed as parameter.

Why would that be a problem? If the allocation is non escaping then it
wouldn't be used in a non inlined call.


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