RFR: 8353345: C2 asserts because maskShiftAmount modifies node without deleting the hash [v3]

[Marc Chevalier]

On Thu, 3 Apr 2025 09:34:42 GMT, Marc Chevalier <mchevalier at openjdk.org> wrote:

>> First delete the hash, then `set_req`. This way, we avoid changing the node (a non-`this` node) without deleting the hash. This wrong ordering is not new from [JDK-8347459](https://bugs.openjdk.org/browse/JDK-8347459), but before that, only `this` was going through this function, so it was ok. But since, it is used with other nodes, hence the need to remove the hash.
>> 
>> Also, not do any of that outside IGVN, but requires to register nested shifts for IGVN in parsing not to miss them later.
>> 
>> Thanks,
>> Marc
>
> Marc Chevalier has updated the pull request incrementally with one additional commit since the last revision:
> 
>   address review comments

Requested changes done! Ready for more review.

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PR Comment: https://git.openjdk.org/jdk/pull/24355#issuecomment-2775259754