RFR: 8253524: C2: Refactor code that clones predicates during loop unswitching [v4]

[Christian Hagedorn]

On Thu, 24 Sep 2020 08:35:42 GMT, Roland Westrelin <roland at openjdk.org> wrote:

>> During unswitching, PhaseIdealLoop::create_slow_version_of_loop()
>> calls PhaseIdealLoop::clone_predicates_to_unswitched_loop() twice, one
>> for each loops, to clone some predicates above each loop. That code is
>> fragile as it (implicitly) requires the fast loop to be processed
>> first. I propose calling
>> PhaseIdealLoop::clone_predicates_to_unswitched_loop() a single time
>> and have it handle both loops in a single pass.
>
> Roland Westrelin has refreshed the contents of this pull request, and previous commits have been removed. The
> incremental views will show differences compared to the previous content of the PR.

Marked as reviewed by chagedorn (Reviewer).

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PR: https://git.openjdk.java.net/jdk/pull/317