LI78299: USAGE OF OMP MAX/MIN REDUCTION OPERATORS CAUSING SYNTAX ERROR IN _PRAGMA

XL C/C++ for Blue Gene/Q Fix Pack 12 (May 2015 Update) for 12.1
XL C/C++ for Blue Gene/Q Fix Pack 14 (May 2016 Update) for 12.1
XL C/C++ for Blue Gene/Q Fix Pack 15 (October 2017 Update) for 12.1
XL C/C++ for Blue Gene/Q Fix Pack 11 (February 2015 Update) for 12.1
XL C/C++ for Blue Gene/Q Fix Pack 13 (August 2015 Update) for 12.1

APAR status

• Closed as program error.

Error description

• The OMP 3.1 reduction operators 'max' and 'min' are causing an
  unexpected syntax error when they are used in a _Pragma
  preprocessing operator.  Usage of the reduction operators in a
  "#pragma" works without issue.
  
  The issue only occurs with the xlc invocation.  The C++ xlC
  invocation is not affected.
  
  
  
     ==== TEST CASE ====
  
  int main()
  {
   int i;
   int N=5;
   double bmax;
  
   _Pragma("omp parallel for private(i) reduction(max:bmax)")
   for(i=0;i<N;i++){}
  
   _Pragma("omp parallel for private(i) reduction(min:bmax)")
   for(i=0;i<N;i++){}
  
   #pragma omp parallel for private(i) reduction(max:bmax)
   for(i=0;i<N;i++){}
  }
  
  
  $ xlc_r -qsmp testcase.c
  "testcase.c", line 7.105: 1506-046 (S) Syntax error.
  "testcase.c", line 10.105: 1506-046 (S) Syntax error.
  $
  

Local fix

• Use #pragma syntax
  

Problem summary

• PROBLEM DESCRIPTION:
  Invalid syntax error for OMP reduction operators max and min
  when used in a _Pragma statement.
  
  USERS AFFECTED:
  Users of the _Pragma syntax and the OMP reduction operators max
  and min.
  

Problem conclusion

• The issue has now been 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:

Fix information

• Fixed component name

  XL C/C++ FOR BG

• Fixed component ID

  5799AG100

Applicable component levels