RFR: 8326135: Enhance adlc to report unused operands [v2]

[Vladimir Kozlov]

On Wed, 21 Feb 2024 08:25:11 GMT, kuaiwei <duke at openjdk.org> wrote:

>> Got it. Please, add comment describing this special case for vector and stack operators.
>
> Thanks for suggestion. I added the example in comments.

Good. Please update comment for vectors too (add `only`):

// special generic vector operands only used in Matcher::pd_specialize_generic_vector_operand


I will submit our testing meanwhile.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17910#discussion_r1497841591