RFR: 8274145: C2: Incorrect computation after JDK-8269752

[Vladimir Kozlov]

On Mon, 27 Sep 2021 08:57:25 GMT, Roland Westrelin <roland at openjdk.org> wrote:

> The bug happens because an If node that follows a CountedLoop is
> replaced by the CountedLoopEnd node of the main loop. Further
> unrolling happens after the If is replaced which causes the condition
> of the CountedLoopEnd node to change. This is made possible by
> JDK-8269752. The fix I propose is to detect that corner case and
> prevent the If to be replaced in that case.

Good.

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Marked as reviewed by kvn (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/5712