[jdk21u-dev] RFR: 8318509: x86 count_positives intrinsic broken for -XX:AVX3Threshold=0

Wed Apr 30 23:12:26 UTC 2025

Backporting JDK-8318509: x86 count_positives intrinsic broken for -XX:AVX3Threshold=0. Fix pulls the value from tmp1, which contains the correct value. Adds test. Ran GHA Sanity Checks, local Tier 1 and 2, and new `test/hotspot/jtreg/compiler/intrinsics/string/TestCountPositives.java` tests. Patch is clean.

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Commit messages:
 - Backport e67550cfec4dbd1c8c2c9869dda34fa09a5c274b

Changes: https://git.openjdk.org/jdk21u-dev/pull/1726/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1726&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8318509
  Stats: 193 lines in 3 files changed: 100 ins; 40 del; 53 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1726.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1726/head:pull/1726

PR: https://git.openjdk.org/jdk21u-dev/pull/1726