RFR: 8361892: AArch64: Incorrect matching rule leading to improper oop instruction encoding [v2]

[Andrew Dinn]

On Mon, 14 Jul 2025 10:28:47 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> Yadong Wang has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   8361892: AArch64: Incorrect matching rule leading to improper oop instruction encoding
>
> To be clear, I would very much prefer to remove the special-case handling for card table base in AArch64/RISC-V AD, rather than piling on more special cases into that rule.

@shipilev One other thing. I believe that the only code that creates a RawPtr ConP for the card table base is in the shared C2 card table barrier set assembler. Now that we have moved to late barrier insertion for G1 (along with Shenandoah and Z) is there now any code -- in the dev tree or in jdk25 -- that will create one of these nodes? If not then perhaps the aarch64 immByteMapBase and loadByteMapBase rules are no longer needed and should be deleted?

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PR Comment: https://git.openjdk.org/jdk/pull/26249#issuecomment-3069103564