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IV32630: UNEXPECTED INCOMPATIBLECLASSCHANGEERROR

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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
    • 








      
              
                            

              

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Document Information


            

            


                        

            Modified date:
            

            16 October 2013
            

            
                      

        


        

        


      

    

  



    

  

  
    
            

          
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