PH18274: INCORRECT LOOP EXECUTION WHEN COMPILING WITH Z/OS COMPILER

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• When going through the assembler code of the while loop
  condition, the problem is that the assignment is performed
  twice, so the first element of t is skipped. If t has more
  elements, the 1st, 3rd, etc. elements are skipped.
  
  The following test case demonstrates this issue:
  
  ===== COMPILE COMMAND:
  c++ test.cpp
  
  
  ===== TESTCASE:
  $cat test.cpp
  #include <stdio.h>
  int main()
  {
      int i = 0;
      const int t[2] = { 1 };
      while (const int x = t[i++])
     {
          printf("In loop: i=%d\n", i);
     }
     printf("After loop: i=%d\n", i);
  
    return 0;
  }
  $
  
  
  ===== ACTUAL OUTPUT:
  $./a.out
  After loop: i=2
  $
  
  
  
  ===== EXPECTED OUTPUT:
  $ ./a.out
  In loop: i=1
  After loop: i=2
  $
  

Local fix

• N/A
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: Users of the zosv2r4 C/C++ compiler          *
  ****************************************************************
  When going through the assembler code of the while loop
  condition, the problem is that the assignment is performed
  twice, so the first element of t is skipped. If it has more
  elements, the 1st, 3rd, etc. elements are skipped.
  

Problem conclusion

• Apply service provided.
  

Temporary fix

Comments

APAR Information

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

  PH18051

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

  PH40309

Modules/Macros

• CCN$P00  CCN$P0X  CCNECICS CCNECWI  CCNED240 CCNEDSCT CCNEDWRT
  CCNEFILT CCNEHIFC CCNEIPA3 CCNEIPAO CCNEMDEP CCNEOPTP CCNEP
  CCNEPP   CCNETBY  CCNLMP00 CCNLMP01 CCNLMP02 CCNLMP03 CCNLMP04
  CCNLMP05 CCNLMP06 CCNLMP07 CCNLMP08 CCNLMP09 CCNLMP0A CCNLMP0B
  CCNLMP0C CCNLMP0D CCNLMP0E CCNLMP0F CCNLMP20 CCNLMP21 CCNLMP22
  CCNLMP23 CCNLMP24 CCNLMP25 CCNLMP26 CCNLMP27 CCNMSGE  CCNMSGT
  CCNPDF00 CCNPDF01 CCNPDF02 CCNPDF03 CCNPDF04 CCNPDF05 CCNPDF06
  CCNPDF07 CCNPDF08 CCNPDF09 CCNPDF0A CCNPDF0B CCNPDF0C CCNPDF0D
  CCNPDF0E CCNPDF0F CCNPDF10 CCNPDF11 CCNPDF12 CCNPDF13 CCNPDF14
  CCNPDF15 CCNPDF16 CCNPDF17 CCNPDF18 CCNPDF19 CCNPDF1A CCNPDF1B
  CCNPDF1C CCNPDF1D CCNPDF1E CCNPDF1F CCNPDF20 CCNPDF21 CCNPDF22
  CCNPDF23 CCNPDF24 CCNPDF25 CCNQIPA
  

Fix information

• Fixed component name

  C/C++ FOR MVS

• Fixed component ID

  56551210A

Applicable component levels

• R7C0 PSY UI65848

     UP19/11/14 P F911

Fix is available

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