LI77249: SIMD_UTIL.CPP:102 ASSERTION ERROR AT -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
May 2013 Update for XL C/C++ for Blue Gene/Q, V12.1
XL C/C++ for Blue Gene/Q Fix Pack 5 (August 2013 Update) for 12.1
XL C/C++ for Blue Gene/Q Fix Pack 6 (November 2013 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 compiler may issue internal compiler error while using -O3
  optimization.
  
  xlC -O3 -I. -c test.cc
  ipa: simd_util.cpp:102: int log2_int(int): Assertion ´x != 0'
  failed.
  Calling signal handler...
  1586-494 (U) INTERNAL COMPILER ERROR: Signal 6.
  /gsa/tlbgsa/projects/x/xlcmpbld/run/vacpp/121_com/bgq/daily/1302
  25/opt/ibmcmp/vacpp/bg/12.1/bin/.orig/xlC: 1501-230 (S)
  Internal compiler error; please contact your Service
  Representative. For more information visit:
  http://www.ibm.com/support/docview.wss?uid=swg21110810
  

Local fix

• Use either noopt or any optimization other than -O3, also -O3
  together with -qhot or -qhot=nosimd
  

Problem summary

• Compiler optimizer is trying to perform SIMD optimizations for
  architectures that do not support vector instructions.
  

Problem conclusion

• Fixed the ICE by disabling SIMD for archs that do not support
  vector instructions.
  

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