RFR: 8341611: [REDO] AArch64: Clean up IndOffXX type and let legitimize_address() fix out-of-range operands [v3]

[Fei Gao]

On Wed, 26 Feb 2025 16:14:10 GMT, Andrew Haley <aph at openjdk.org> wrote:

>>> The reason being: this patch cleans up and simplifies memory ops on AArch64. That's nice, but it doesn't fix any bug. If we could do it in a self-contained way, and it's beginning to look that we can't, then that would be fine. But I don't think it's worth the possibility of regressions. I've seen too many "cleanups" that have broken things.
>> 
>> @theRealAph yes, I agree. I'll stop processing this pull request and close it. Thanks for your quick response. 
>> 
>> BTW, now for [indOffIN/indOffLN](https://github.com/openjdk/jdk/blob/75420e9314c54adc5b45f9b274a87af54dd6b5a8/src/hotspot/cpu/aarch64/aarch64.ad#L5466), `legitimize_address()` fixes some out-of-range offsets. It looks like there is still possibility of breaking `implicit null check`, isn't there? Do you think if it's worthwhile to move to this original idea: [adding more memory operands for compressed pointers](https://github.com/openjdk/jdk/pull/16991/commits/1895cf3112d341b0ae8beb6dd9d332f6a2c5d5fc)? Thanks.
>
>> BTW, now for [indOffIN/indOffLN](https://github.com/openjdk/jdk/blob/75420e9314c54adc5b45f9b274a87af54dd6b5a8/src/hotspot/cpu/aarch64/aarch64.ad#L5466), `legitimize_address()` fixes some out-of-range offsets. It looks like there is still possibility of breaking `implicit null check`, isn't there? Do you think if it's worthwhile to move to this original idea: [adding more memory operands for compressed pointers](https://github.com/openjdk/jdk/pull/16991/commits/1895cf3112d341b0ae8beb6dd9d332f6a2c5d5fc)? Thanks.
> 
> I can't think of a better alternative.

Thanks @theRealAph .

Work will be continued in a new pull request.

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PR Comment: https://git.openjdk.org/jdk/pull/22862#issuecomment-2685620128