RFR: 8350459: MontgomeryIntegerPolynomialP256 multiply intrinsic with AVX2 on x86_64 [v4]

[Anthony Scarpino]

On Mon, 10 Mar 2025 23:05:10 GMT, Volodymyr Paprotski <vpaprotski at openjdk.org> wrote:

>> test/jdk/com/sun/security/util/math/intpoly/MontgomeryPolynomialFuzzTest.java line 123:
>> 
>>> 121:         }
>>> 122: 
>>> 123:         if (rnd.nextBoolean()) {
>> 
>> Why is this done randomly?  Wouldn't we want to check these situations every time?
>
> I was mostly attempting to test 'random paths' through the code, and this was a way to pseudo-randomly accomplish that. (i.e. a product of a difference, a product of a product.. and so on..)
> 
> Since this is looping, we got 50% chance of getting both, without me having to write/think-through all the many permutations of what input/outputs to each operations can be.
> 
> (Extend the loop count to run for several hours during development.. and it does wonders to testing corner cases. Have been following this 'template' in most my PRs)

Randomness isn't idea for reproducibility.  If a failure occurs, is it obvious what operations were done?  I don't see any stdout or stderr messages to know what operations happen to bring about a possible failure.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23719#discussion_r2004074368