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  1. JDK
  2. JDK-8267726

ZGC: array_copy_requires_gc_barriers too strict

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    Details

    • Type: Enhancement
    • Status: Resolved
    • Priority: P4
    • Resolution: Fixed
    • Affects Version/s: 17
    • Fix Version/s: 17
    • Component/s: hotspot
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    • Resolved In Build:
      b25

      Description

      While doing the c2 TOI for the GC team I was surprised by an arraycopy clone that was eliminated with G1 but not with ZGC.

      Further investigation revealed that array_copy_requires_gc_barriers has been interpreted too strict. During parse and optimization phase it should return false - no special handling is needed. When deconstructing an arraycopy the proper barriers are added to the loads.

      Only during expansion, when the the correct arraycopy call must be used, must array_copy_requires_gc_barriers return true.

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              Assignee:
              neliasso Nils Eliasson
              Reporter:
              neliasso Nils Eliasson
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