RFR: 8283726: x86_64 intrinsics for compareUnsigned method in Integer and Long [v3]

[Jatin Bhateja]

On Wed, 29 Jun 2022 02:22:02 GMT, Quan Anh Mai <duke at openjdk.org> wrote:

>> I do not follow your comment, allocation decisions purely based on LRGs interferences and data flow attributes attached to operands and is agnostic to encoding block contents.
>
> Your suggestion requires us having additional `TEMP dst` for the match rule. Thanks.

Yes, macro fusion is a fine microarchitectural optimization which can reduce load on entire execution pipeline and is **deterministic** for specific pair of cmp + jump instructions, you have aggregated destination's defs and its usages towards the tail which can save TEMP attribution on destination operand and may save a redundant spill only for high register pressure blocks. I am ok with existing handling.

Thanks for your explanations.

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PR: https://git.openjdk.org/jdk/pull/9068