IV14086: JAVA METHOD MISBEHAVES WHEN JIT-COMPILED

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • Error Message: When a Java method with unusual characteristics
    has been JIT-compiled, it may produce incorrect I/O, cause an
    ABEND or unexpected exception, or crash.
    .
    Stack Trace: N/A
    .
    This issue will most likely affect a Java method with a
    combination of branches, method calls, loops, and unusual
    definitions and uses of loop induction variables.
    

Local fix

  • This issue can be avoided using the -Xjit:disableGlobalVP
    option. Note that this option prevents the JIT compiler from
    performing many types of optimization. This will cause a
    significant impact on performance.
    

Problem summary

  • The problem is caused when the JIT compiler performs an
    optimization known as value propagation, and mistakenly
    concludes that a definition of a variable is unreachable code.
    As a result, it propagates an incorrect alternative definition
    of the variable to a use later on in the method, causing
    unexpected behaviour.
    

Problem conclusion

  • This defect will be fixed in:
    6.0.0 SR11
    6.0.1 SR2
    7.0.0 SR1
    .
    The JIT compiler has been updated to prevent the incorrect
    propagation.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IV14086

  • Reported component name

    JIT

  • Reported component ID

    620700124

  • Reported release

    600

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-01-27

  • Closed date

    2012-01-27

  • Last modified date

    2012-06-01

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

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

    PM57142

Fix information

  • Fixed component name

    JIT

  • Fixed component ID

    620700124

Applicable component levels

  • R600 PSY

       UP

  • R260 PSY

       UP



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Document information


More support for:

Runtimes for Java Technology
Just In Time (JIT) Compiler

Software version:

6.0

Reference #:

IV14086

Modified date:

2012-06-01

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