RFR(XS): 8211451: ~2.5% regression on compression benchmark starting with 12-b11

Roland Westrelin rwestrel at redhat.com
Tue Oct 23 15:30:30 UTC 2018

Hi Vladimir,

Vladimir Kozlov <vladimir.kozlov at oracle.com> writes:

> You are saying that don't do that check since this condition will not help to avoid overflow anyway. Right?


> And to make this regression go away we need to convert test's loop into counted loop and unroll it even with 'ne' 
> condition. Right?


> Can we strengthen code by adding runtime check (predicate) for 'ne' case that init < limit? We do this for limit today.

Would it share the uncommon trap call with the loop limit check or would
that be an entirely new Deoptimization::Reason_XXX?

While we're doing it why not convert:

init_t->_hi > max_jint - stride_con

into a runtime check as well?


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