RFR: 8279560: AArch64: generate_compare_long_string_same_encoding and LARGE_LOOP_PREFETCH alignment

[Andrew Haley]

On Mon, 10 Jan 2022 16:34:00 GMT, Andrew Haley <aph at openjdk.org> wrote:

> > > This looks fine to me, but someone else should take a look too.
> > > Are there any benchmark affected by this change? A targeted String microbenchmark run would be enough.
> > 
> > 
> > Thank you for your comment. The fixed version has been tested on Apple M1 (using #5129 's benchmark) without performance degradation.
> 
> It'd be nice to see an improvement. I suspect (but don't know) that this doesn't affect AArch64.

Actually, it's probably worth doing anyway, even if no AArch64 port has the weird Intel code alignment stall, just because it makes the loop sit nicely on cache lines.

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PR: https://git.openjdk.java.net/jdk/pull/7007