IV78328: INCONSISTENT RETURN VALUE FOR JAVA/LANG/MATH.LOG ON X86

APAR status

• Closed as program error.

Error description

• Error Message: Value of log(x) changes after java/lang/Math.log
  has been compiled for certain values of x
  .
  Stack Trace:
  .
  This problem is only seen on x86 platforms.
  

Local fix

Problem summary

• The problem happens because the JIT compiler uses special
  inlined assembly code involving floating point operations to
  calculate the value of java/lang/Math.log and the accuracy is
  not consistent with the computation done by the interpreter.
  This results in certain log(x) return values changing after the
  method which computes them gets compiled.
  

Problem conclusion

• The JIT compiler has been updated to calculate the
  java/lang/Math.log value with the same accuracy as the
  interpreter.
  .
  This APAR will be fixed in the following Java Releases:
     7 R1 SR3 FP20  (7.1.3.20)
  .
  Contact your IBM Product's Service Team for these Service
  Refreshes and Fix Packs.
  For those running stand-alone, information about the available
  Service Refreshes and Fix Packs can be found at:
             https://www.ibm.com/developerworks/java/jdk/
  

Temporary fix

Comments

APAR Information

• 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

• R130 PSY

     UP