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  1. JDK
  2. JDK-8285973

x86_64: Improve fp comparison and cmove for eq/ne

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    Details

    • Type: Enhancement
    • Status: Resolved
    • Priority: P4
    • Resolution: Fixed
    • Affects Version/s: 19
    • Fix Version/s: 19
    • Component/s: hotspot
    • Labels:
    • Subcomponent:
    • Resolved In Build:
      b24
    • CPU:
      x86

      Description

      - Fp comparison with eq/ne does not have to process ZF when both inputs of the comparison are the same.
      - CMove nodes lack the match rules for cmpOpUCF2, leading to those with eq/ne falling to cmpOpU, which has a really high overhead of fixing the flags.
      - Use Math.abs(v) == POSITIVE_INFINITY for Double/Float.isInfinite, which reduces 1 comparison and 1 branch.

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              Assignee:
              sviswanathan Sandhya Viswanathan
              Reporter:
              qamai Quan Anh Mai
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                Updated:
                Resolved: