LI77528: INTERNAL COMPILER ERROR WITH -O3

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 7 (February 2014 Update) for 12.1
XL C/C++ for Blue Gene/Q Fix Pack 8 (May 2014 Update) for 12.1
XL C/C++ for Blue Gene/Q Fix Pack 9 (August 2014 Update) for 12.1
XL C/C++ for Blue Gene/Q Fix Pack 10 (November 2014 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 following test case causes the compiler to produce an
  internal compiler error at -O3. It works fine with -O2.
  
  ===== COMPILE COMMAND:
  bgxlc++ -O3 -c test.cpp
  
  ===== TESTCASE:
  $ cat test.cpp
  volatile tmp;
  
  
  
  void
  
  set_b(bool *b) {
  
     *b=true;
  
  }
  
  
  
  void foo()
  
  {
  
     double l_data[2], g_data[2];
  
     bool rho_upd, e_upd;
  
  
  
     set_b(&rho_upd);
  
     set_b(&e_upd);
  
  
  
     l_data[0] = 0.0;
  
     // The internal compiler error occurs when trying to compile
  the line below
  
     l_data[1] = (rho_upd || e_upd) ? 1.0 : 0.0;
  
  
  
     tmp += (l_data[0] + l_data[1]);
  
  }
  $
  
  
  
  ===== ACTUAL OUTPUT:
  Compiler produces an internal compiler error.
  
  
  ===== EXPECTED OUTPUT:
  Internal compiler error should not occur.
  

Local fix

• Use -O2
  

Problem summary

• Clients who compile with -O3 may be affected by this issue.
  
  The compiler produces an internal compiler error due to a
  type mismatch caused during simplification of an if-conversion.
  

Problem conclusion

• The compiler has been fixed to handle the above scenario.
  

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