PH18051: INCORRECT LOOP EXECUTION WHEN COMPILING WITH Z/OS COMPILER

APAR status

• Closed as fixed if next.

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

• This issue has been fixed in the latest V2R4 November 2019 PTF.
  

Problem conclusion

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:

  PH18274

Fix information

Applicable component levels