RFR: 8345296: AArch64: VM crashes with SIGILL when prctl is disallowed [v3]

[Evgeny Astigeevich]

On Mon, 2 Dec 2024 17:24:04 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

>> src/hotspot/cpu/aarch64/vm_version_aarch64.cpp line 452:
>> 
>>> 450:               "Disabling SVE. Specify -XX:UseSVE=0 to shun this warning.");
>>> 451:       FLAG_SET_DEFAULT(UseSVE, 0);
>>> 452:     } else if (vl < FloatRegister::sve_vl_min || ((vl % FloatRegister::sve_vl_min) != 0) || !is_power_of_2(vl)) {
>> 
>> I think `vl < FloatRegister::sve_vl_min` is redundant.
>> It is covered by `vl % FloatRegister::sve_vl_min) != 0`.
>
> I thought so too, but it is not, if `vl == 0`?

It covers the case: `vl == 0`.

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PR Review Comment: https://git.openjdk.org/jdk/pull/22479#discussion_r1866291313