RFR: 8354242: VectorAPI: combine vector not operation with compare [v9]

[erifan]

On Tue, 8 Jul 2025 08:56:44 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

> predicate cannot be negated AND the vector is all ones. Can you explain this condition?

Ok, I'll add a comment for it.

> Why do you guard against VectorNode::is_all_ones_vector(in2) at all?

Because one of the nodes in the supported patterns by this PR needs to be `MaskAll` or `Replicate`. And this function `VectorNode::is_all_ones_vector` just meets our check for `MaskAll` and `Replicate`. Actually I don't quite understand your question. I have two understandings:
1. Not all nodes that `VectorNode::is_all_ones_vector` returns true are `MaskAll` or `Replicate`, but other nodes that do not meet the conditions.
2. Here, it does not need to be a vector with every bit 1, it only needs to be an `all true` mask.

Which one do you mean? Or something else? Thanks~

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PR Review Comment: https://git.openjdk.org/jdk/pull/24674#discussion_r2192019309