RFR(S): 8244086: Following 8241492, strip mined loop may run extra iterations

[Roland Westrelin]

Hi Martin,

> Given the huge amount of problems related to LSM I wonder if it's worth maintaining it. It comes with a high price.

And default back to a safepoint in every loop iteration for latency
sensitive gcs? People involved with gcs would need to comment on whether
they think it's acceptable.

Anyway, I disagree with the "huge amount of problems" comment. All non
trivial C2 changes that I've been involved with have had a long bug
tail. I don't think LSM is better or worse in that regard.

> Nevertheless, your version looks at least correct to me.

Thanks for the review.

> loopnode.cpp:
> Please add your formula to the comment.

Actually in the review thread for 8223051, John suggested some
refactoring that would apply here as well. I'll update this webrev.

> TestStripMinedLimitBelowInit.java:
> I suggest to use -XX:-TieredCompilation

Why that?

Roland.