RFR: 8365991: AArch64: Ignore BlockZeroingLowLimit when UseBlockZeroing is false [v4]

[Andrew Haley]

On Tue, 28 Oct 2025 07:55:42 GMT, Patrick Zhang <qpzhang at openjdk.org> wrote:

> I would like to reiterate that I have no objection to the functions when the `-XX:+UseBlockZeroing` option is set, everything can keep as is. My point is that `BlockZeroingLowLimit` serves literally/specifically as a switch to control whether DC ZVA instructions are generated for clearing instances under a specified bytes size limitation, rather than for deciding between unrolling and callout. Therefore, it should NOT affect the code-gen results any longer when `-XX:-UseBlockZeroing` is set, should it?

It does not. When `-XX:-UseBlockZeroing` is set,  `BlockZeroingLowLimit` is ignored.

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PR Comment: https://git.openjdk.org/jdk/pull/26917#issuecomment-3455117311