LI76044: INCORRECT CALCULATION RESULTS WITH -QHOT

July 2011 Update for XL Fortran for Linux, V13.1
October 2011 Update for XL Fortran for Linux, V13.1
June 2012 Update for XL Fortran for Linux, V13.1
October 2012 Update for XL Fortran for Linux, V13.1
XL Fortran for Linux Fix Pack 8 (June 2013 Update) for 13.1

APAR status

• Closed as program error.

Error description

• When compiling with -qhot or -O3 (which implies -qhot=level=0),
  incorrect values are seen when the compiler performs function
  splitting optimizations.  The function splitting optimizing
  behaviour may be related to the usage of -qarch settings that
  include support for square root instructions.
  
  Values in the function stored as Fortran variables with the SAVE
  attribute, or C/C++ variables with function-scope static
  specifiers may not be stored correctly, resulting in unexpected
  results.
  
  Note:  on Linux, the default -qarch setting, -qarch=ppc64grsq,
  includes support for sqrt instructions.
  

Local fix

• Users may be able to disable the function splitting behaviour in
  some cases by using a -qarch setting that does not include
  support for square root instructions.
  

Problem summary

• PROBLEM DESCRIPTION:
  Incorrect optimization of procedure with function scope static.
  
  USERS AFFECTED:
  Users that compile with optimization and have function scope
  static may encounter this problem.
  

Problem conclusion

• The issue was corrected.
  

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:

  IZ99242

Fix information

• Fixed component name

  XL FORTRAN LINU

• Fixed component ID

  5724X1600

Applicable component levels

• RD10 PSY

     UP