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  1. JDK
  2. JDK-8080588 VarHandles development
  3. JDK-8130923

C1 trouble in VarHandle.getObject tests

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    • Sub-task
    • Resolution: Fixed
    • P4
    • 9
    • None
    • core-libs
    • None

    Description

      It seems that in addition to JDK-8130920, getObject pays additional cost with C1:
      http://cr.openjdk.java.net/~shade/8130923/ObjectTest.java

      o.o.v.get.acc.ObjectTest.plain avgt 15 16.382 ± 0.009 ns/op
      o.o.v.get.acc.ObjectTest.unsafe avgt 15 18.902 ± 0.009 ns/op
      o.o.v.get.acc.ObjectTest.varHandle avgt 15 104.206 ± 5.003 ns/op

      The disassembly shows additional Class.cast dance:
       http://cr.openjdk.java.net/~shade/8130923/c1.perfasm
       http://cr.openjdk.java.net/~shade/8130923/c2.perfasm

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          is blocked by

          Enhancement - null JDK-8131782 C1 Class.cast optimization breaks when Class is loaded from static final

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

          Enhancement - null JDK-8135033 C1 should fast-path Object.class.isInstance(obj) to null check

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

          Enhancement - null JDK-8131682 C1 should use multibyte nops everywhere

          • P3 - Major loss of function.
          • Resolved

          Enhancement - null JDK-8131782 C1 Class.cast optimization breaks when Class is loaded from static final

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

          Sub-task - The sub-task of the issue JDK-8130920 C1 trouble in VarHandle.get tests

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

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              shade Aleksey Shipilev
              shade Aleksey Shipilev
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              Dates

                Created:
                Updated:
                Resolved: