RFR: 8305637: Remove Opaque1 nodes for Parse Predicates and clean up useless predicate elimination [v2]

[Roland Westrelin]

On Tue, 29 Aug 2023 08:41:57 GMT, Christian Hagedorn <chagedorn at openjdk.org> wrote:

> > Opaque1 nodes fold away after loop opts which guarantees the parse predicate are removed too after loop opts. In the new code, without the Opaque1 nodes, what causes the parse predicate to be removed after loop opts?
> 
> When creating a new `ParsePredicateNode`, we are registering it for post loop opts IGVN:

Makes sense. Thanks for the details.

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PR Comment: https://git.openjdk.org/jdk/pull/15449#issuecomment-1699305470