RFR: 8350896: Integer/Long.compress gets wrong type from CompressBitsNode::Value [v5]

[Emanuel Peter]

On Wed, 23 Apr 2025 08:36:50 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Hi All,
>> 
>> This bugfix patch fixes incorrect value computation for Integer/Long. compress APIs.
>> 
>> Problems occur with a constant input and variable mask where the input's value is equal to the lower bound of the mask value., In this case, an erroneous value range estimation results in a constant value. Existing value routine first attempts to constant fold the compression operation if both input and compression mask are constant values; otherwise, it attempts to constrain the value range of result based on the upper and lower bounds of mask type.
>> 
>> New IR test covers the issue reported in the bug report along with a case for value range based logic pruning.
>> 
>> Kindly review and share your feedback.
>> 
>> Best Regards,
>> Jatin
>
> Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Review comments resoultions

>  Let me tune this check and update the test.

For me to approve this code, you will have to do more than that. I will need:
- Proof of the implemented logic.
- More tests.

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PR Comment: https://git.openjdk.org/jdk/pull/23947#issuecomment-2850590832