RFR: 8366357: C2 SuperWord: refactor VTransformNode::apply with VTransformApplyState [v3]

[Emanuel Peter]

On Thu, 28 Aug 2025 14:42:46 GMT, Manuel Hässig <mhaessig at openjdk.org> wrote:

>> Emanuel Peter has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   For Christian: use phase->intcon instead
>
> src/hotspot/share/opto/superword.cpp line 3072:
> 
>> 3070: 
>> 3071:   // 1.1: con
>> 3072:   Node* xbic = phase()->intcon(is_sub ? -con : con);
> 
> What changed that you need/want `PhaseIdealLoop*` here instead of `PhaseIterGVN*`?

@chhagedorn Suggested it here: https://github.com/openjdk/jdk/pull/26987#discussion_r2307425745

That way, we set the control of the new constant. It was not strictly necessary, but good practice.

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PR Review Comment: https://git.openjdk.org/jdk/pull/26987#discussion_r2307649223