RFR: 8330165: C2: make superword consistently use PhaseIdealLoop::register_new_node() [v2]

[Vladimir Kozlov]

On Fri, 12 Apr 2024 14:58:56 GMT, Roland Westrelin <roland at openjdk.org> wrote:

>> Another set of changes from 8275202. There are cases in superword
>> where new nodes are not assigned control. I believe they are harmless
>> currently because superword is the last pass of optimizations. I also
>> cleaned up the code so it always uses `register_new_node()`. There are
>> a couple places where `intcon()` should be used.
>
> Roland Westrelin has updated the pull request incrementally with one additional commit since the last revision:
> 
>   review

Good.

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Marked as reviewed by kvn (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/18760#pullrequestreview-2001690210