IBM Support

IV47767: ARRAY ELEMENT INITIALIZED INCORRECTLY BY DOWNWARD COUNTING LOOP

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APAR status

  • Closed as program error.

Error description

  • Error Message: N/A
    .
    Stack Trace: N/A
    .
    In a compiled Java method, a loop that writes a constant value
    to consecutive elements of an array in reverse order may leave
    some of the elements with incorrect values. For example, the
    code below may trigger the incorrect behaviour:
    do {
     i--;
     a<OSB>i<CSB> = CONSTANT;
    } while (i > N);
    

Local fix

  • This issue can be worked around with the
    -Xjit:disableIdiomRecognition option.
    

Problem summary

  • The problem is caused by a JIT optimization which recognizes the
    array initialization loop, but incorrectly calculates the number
    of elements to be initialized.
    

Problem conclusion

  • This defect will be fixed in:
    6.0.1 SR7
    7.0.0 SR6
    6.0.0 SR15
    .
    The JIT compiler has been updated to correctly calculate the
    number of elements to be initialized.
    

Temporary fix

Comments

APAR Information

  • APAR number

    IV47767

  • Reported component name

    JIT

  • Reported component ID

    620700124

  • Reported release

    260

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-08-30

  • Closed date

    2013-09-23

  • Last modified date

    2013-09-23

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

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

Fix information

  • Fixed component name

    JIT

  • Fixed component ID

    620700124

Applicable component levels

  • R260 PSY

       UP

  • R600 PSY

       UP



Document information

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

Software version: 260

Reference #: IV47767

Modified date: 23 September 2013