RFR: 8370666: VectorAPI: Add clear comments for vector mask relative code in c2

[Emanuel Peter]

On Fri, 9 Jan 2026 13:26:52 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> The VectorMask implementation in Vector API involves complex interactions between types, nodes, and platform-specific
>> features, making the related code in HotSpot difficult to understand and review.
>> 
>> This patch adds comprehensive comments for vector mask related types, nodes, and methods in C2 to improve code clarity and
>> maintainability.
>> 
>> Note: This patch only adds comments; no functional changes are made.
>
> src/hotspot/share/opto/vectornode.hpp line 1855:
> 
>> 1853: //------------------------------VectorLoadShuffleNode------------------------------
>> 1854: // The target may not directly support the rearrange operation for an element type.
>> 1855: // In those cases, we can transform the rearrange into a different element type.
> 
> Can you  specify a bit more about the inputs and outputs, and what exactly the transformation does?

Is this a memory instruction? Because it is called `Load`. If not: can we rename it?

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PR Review Comment: https://git.openjdk.org/jdk/pull/29130#discussion_r2676197752