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  1. JDK
  2. JDK-8285695

Performance regression in C2 loop unrolling

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    • Bug
    • Resolution: Not an Issue
    • P3
    • None
    • 19
    • hotspot

    Description

      Several changes to code controlling C2's loop unrolling optimizations appear to have caused it to miss many unrolling opportunities at runtime in recent builds. https://github.com/openjdk/jdk/pull/7822 is currently a suspect for causing this performance regression

      Discussion: https://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2022-April/054780.html

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          relates to

          Bug - A problem which impairs or prevents the functions of the product. JDK-8283187 C2: loop candidate for superword not always unrolled fully if superword fails

          • P4 - Minor loss of function, or other problem where easy workaround is present.
          • Resolved

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              Unassigned Unassigned
              jwaters Julian Waters
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                Resolved: