RFR: 8340141: C1: rework ciMethod::equals following 8338471

[Dean Long]

On Wed, 25 Sep 2024 22:52:18 GMT, Dean Long <dlong at openjdk.org> wrote:

>> Instead of bailout in alternative approach we can change `cha_monomorphic_target` to `nullptr` in code which is looking for it in previous lines. `target` will be used for call  and we will loose a little performance when JVMTI is used instead of skipping compilation. Am I missing something?
>
> @vnkozlov , I like the alternative approach better.  I went with the current approach because I was thinking it would be simpler than the bailout, but I changed my mind after writing both out.
> 
> Yes, we can change cha_monomorphic_target to nullptr instead of bailing out.  But my understanding is any use of old/redefined methods will cause the compilation to be thrown out when we try to create the nmethod, so we are avoiding wasted work by bailing out early.

> @dean-long, may be I misunderstand your statement. Are you re-writing the fix or keep current?

Either one is fine with me.  I could make a separate draft PR with the alternative solution if that helps reviewers decide.

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PR Comment: https://git.openjdk.org/jdk/pull/21148#issuecomment-2400626113