IY39852: INCORRECT OUTPUT(INFINITE LOOP) WITH -O3 AND -QPDF1.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• When compiling test case with -O3 and -qpdf1, the compiler
  generates an executable that contains a infinite loop, which
  causes it to hang.
  .
  $ xlC -O3 -qpdf1 t2.cpp
        19  1500-010: (W) WARNING in main: Infinite loop.
   Program may not stop.
  $ a.out
  [hangs]
  .
  Following the logistics of the test case, there should not
  be any infinite loops. This may be caused by incorrect
  code rearrangement during the optimization phase.
  .
  This problem seems to during in -O2 as well.
  .
  I did not run the program through any debuggers because it
  involves optimization.
  .
  ENVIRONMENT:
  ------------
  AIX4L,5L
  VAC++ 600
  .
  TESTCASE:
  ---------
  // test.cpp
  #define FALSE 0
  #define TRUE  1
  .
  int main(void)
  {
  int status;
  .
  if ( FALSE )
   do {
    printf("Should not be here\n");
   } while ( *(&status) == 0 && 1 );
  .
  if ( FALSE ) ;
  else if ( TRUE )
  {
   do_again:
   printf("You are in else-if block\n");
   if ( FALSE )
    goto do_again;
  }
  if ( FALSE )
   goto do_again;
  .
  printf("Exit from the function\n");
  return(0);
  .
  }
  .
  COMPILE COMMAND:
  ----------------
  xlC -O3 -qpdf1 test.cpp
  .
  WORKAROUND:
  -----------
  Don't compile with -O3 and -qpdf1 together.
  .
  EXPECTED RESULTS:
  -----------------
  Clean compile without warning message.
  An executable without infinite loops.
  .
  ACTUAL RESULTS:
  ---------------
  19  1500-010: (W) WARNING in main: Infinite loop.  Program may
  not stop.
  An executable that hangs.
  

Local fix

• Don't compile with -O3 and -qpdf1 together.
  

Problem summary

• Same as submitter's text.
  

Problem conclusion

• Development checked in a fix that resolved customer's problem.
  

Temporary fix

Comments

APAR Information

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

  IY36719

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

Fix information

• Fixed component name

  XL FORTRAN AIX

• Fixed component ID

  5765F7000

Applicable component levels

• R810 PSN U487189

     UP03/02/13 I 1000

Fix is available

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