RFR: 8279282: [vectorapi] Matcher::supports_vector_comparison_unsigned is not needed on x86

Wed Jan 5 10:37:33 UTC 2022

Hi,

Currently, unsigned comparison on AVX is implemented by zero extending elements and comparing the results. This leads to unnecessary complexity. This patch changes the implementation to use the identity existing in `Integer/Long.compareUnsigned`, that is `compareUnsigned(x, y) == compare(x ^ min_value, y ^ min_value)`.

Thank you very much.

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Commit messages:
 - unsigned comparison enhancement

Changes: https://git.openjdk.java.net/jdk/pull/6966/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=6966&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8279282
  Stats: 171 lines in 6 files changed: 38 ins; 99 del; 34 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6966.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6966/head:pull/6966

PR: https://git.openjdk.java.net/jdk/pull/6966