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IV32630: UNEXPECTED INCOMPATIBLECLASSCHANGEERROR

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • Error Message: An unexpected IncompatibleClassChangeError is
    thrown from a JIT-compiled method. In a different manifestation,
    an incorrect ArrayIndexOutOfBoundsException is also thrown.
    .
    Stack Trace: N/A
    .
    Methods with loops in them are susceptible to this problem.
    

Local fix

  • -Xjit:disableLoopVersioner
    

Problem summary

  • During the JIT compilation of a method with hot loops, an
    optimization called loop versioning incorrectly moves some code
    outside of a loop, along with variables that are loop-variant.
    This causes the resulting compiled method to behave in an
    unexpected manner.
    

Problem conclusion

  • This defect will be fixed in:
    7.0.0 SR4
    6.0.1 SR5
    6.0.0 SR13
    5.0.0 SR16
    .
    The JIT compiler has been modified to correctly identify the
    code paths and variables which qualify for moving outside of the
    loop.
    

Temporary fix

  • -Xjit:disableLoopVersioner
    

Comments

APAR Information

  • APAR number

    IV32630

  • Reported component name

    JIT

  • Reported component ID

    620700124

  • Reported release

    600

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-11-27

  • Closed date

    2012-12-06

  • Last modified date

    2013-10-16

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

    IV37329 IV37513

Fix information

  • Fixed component name

    JIT

  • Fixed component ID

    620700124

Applicable component levels

  • R600 PSY

       UP



Document information

More support for: Runtimes for Java Technology
Just In Time (JIT) Compiler

Software version: 6.0

Reference #: IV32630

Modified date: 16 October 2013