RFR: 8308994: C2: Re-implement experimental post loop vectorization [v4]

[Pengfei Li]

On Tue, 4 Jul 2023 02:23:32 GMT, Pengfei Li <pli at openjdk.org> wrote:

>> Suggested solution: track the last memory state per slice, just like I recently did in `SuperWord::schedule_reorder_memops` with `current_state_in_slice`.
>
> I'm not quite familiar with memory slice. Will do more investigation and come back later.

After some study, I know my current approach does create some unnecessary memory dependence. Will fix this after some refactoring work.

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PR Review Comment: https://git.openjdk.org/jdk/pull/14581#discussion_r1338286246