IV50061: AND/OR/XOR WITH ONE OF THE OPERANDS SHIFTED BY 32 MIGHT PRODUCE INCORRECT RESULT

APAR status

• Closed as program error.

Error description

• Error Message: N/A
  .
  Stack Trace: N/A
  .
  A Java program performing bitwise and/or arithmetic operations
  on long variables produces incorrect result.
  

Local fix

• This problem can be avoided by setting the JVM option
  -Xjit:exclude={full method name} for the method that is causing
  the issue. However, this may cause some performance degradation.
  

Problem summary

• The issue happens only on 64-bit System z with AND, OR and XOR
  operations where one of the operands is a long variable that is
  right-shifted by 32. The JIT compiler incorrectly generates code
  that uses only the low half of the long instead of the whole
  64-bit value. The problem could potentially affect arithmetic
  expressions that do not explicitly involve bitwise operations,
  since certain arithmetic operations could be optimized into
  bitwise ones.
  

Problem conclusion

• This defect will be fixed in:
  7.0.0 SR6
  6.0.1 SR7
  6.0.0 SR15
  5.0.0 SR16 FP4
  .
  The JIT compiler has been updated to compile bitwise operations
  of shifted long values correctly.
  

Temporary fix

Comments

APAR Information

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

  IV50060

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

Fix information

• Fixed component name

  JAVA 5 JIT

• Fixed component ID

  620500124

Applicable component levels

• R500 PSY

     UP