RFR: 8298935: fix cyclic dependency bug in create_pack logic in SuperWord::find_adjacent_refs [v9]

Tue Feb 28 15:31:34 UTC 2023

On Tue, 28 Feb 2023 10:29:32 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> Sounds good.
>
> @jatin-bhateja I now have a first version out of the `test/hotspot/jtreg/compiler/loopopts/superword/TestDependencyOffsets.java`. It seems to work for `sse4.1 ... avx512`. I'm now testing it for `asimd`.
> And then I will proceed to add the features for `-XX:+AlignVector`, with the modulo check.

Update: I cannot use `SuperWordMaxVectorSize`, because it is regulated down on x86 to be at most `MaxVectorSize`. But on `aarch64` the flag `SuperWordMaxVectorSize` does not seem to be adjusted. @fg1417 do you think this is correct / on purpose? Maybe this is just an unfortunate but harmless inconsistency. I guess in `SuperWord::max_vector_size` we first get the info from `Matcher::max_vector_size` (based on `MaxVectorSize`), and then upper bound that based on `SuperWordMaxVectorSize`.

TLDR: I am using `MaxVectorSize` instead of `SuperWordMaxVectorSize` now.

-------------

PR: https://git.openjdk.org/jdk/pull/12350