RFR: 8342662: C2: Add new phase for backend-specific lowering [v6]

[Quan Anh Mai]

On Tue, 7 Jan 2025 22:47:58 GMT, Vladimir Ivanov <vlivanov at openjdk.org> wrote:

>> Jasmine Karthikeyan has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Implement apply_identity
>
> Were there any experiments conducted to port existing lowering transformations to the new pass? 
> 
> As we discussed before, there are multiple places in the code where lowering takes place. It is still not clear to me how much proposed solution unifies across existing use cases. What I'd really like to avoid is yet another peculiar way to perform lowering transformations in C2.

@iwanowww Gentle ping on this
@jaskarth I think you should merge master to keep the branch reasonably up-to-date

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PR Comment: https://git.openjdk.org/jdk/pull/21599#issuecomment-2707315180