IZ91493: LONG COMPILE TIME IN XLCCODE WITH -O3

January 2011 PTF for XL C/C++ for AIX, V11.1
May 2011 PTF for XL C for AIX, V11.1
May 2011 PTF for XL C/C++ for AIX, V11.1
August 2011 PTF for XL C/C++ for AIX, V11.1
November 2011 PTF for XL C/C++ for AIX, V11.1
January 2012 PTF for XL C for AIX, V11.1
January 2012 PTF for XL C/C++ for AIX, V11.1
April 2012 PTF for XL C for AIX, V11.1
April 2012 PTF for XL C/C++ for AIX, V11.1
July 2012 PTF for XL C/C++ for AIX, V11.1
October 2012 PTF for XL C for AIX, V11.1
October 2012 PTF for XL C/C++ for AIX, V11.1
February 2013 PTF for XL C for AIX, V11.1
February 2013 PTF for XL C/C++ for AIX, V11.1
XL C/C++ for AIX Fix Pack 14 (May 2013 PTF) for 11.1
XL C for AIX Fix Pack 14 (May 2013 PTF) for 11.1
XL C/C++ for AIX Fix Pack 15 (August 2013 PTF) for 11.1
XL C for AIX Fix Pack 15 (August 2013 PTF) for 11.1
XL C/C++ for AIX Fix Pack 16 (November 2013 PTF) for 11.1
XL C for AIX Fix Pack 17 (February 2014 PTF) for 11.1
XL C/C++ for AIX Fix Pack 17 (February 2014 PTF) for 11.1
XL C/C++ for AIX Fix Pack 18 (May 2014 PTF) for 11.1
XL C/C++ for AIX Fix Pack 19 (August 2014 PTF) for 11.1
XL C/C++ for AIX Fix Pack 20 (November 2014 PTF) for 11.1
XL C for AIX Fix Pack 21 (April 2015 PTF) for 11.1
XL C/C++ for AIX Fix Pack 21 (April 2015 PTF) for 11.1
XL C/C++ for AIX Fix Pack 22 (September 2015 PTF) for 11.1
XL C for AIX Fix Pack 23 (March 2016 PTF) for 11.1
XL C/C++ for AIX Fix Pack 23 (March 2016 PTF) for 11.1
XL C for AIX Fix Pack 24 (September 2016 PTF) for 11.1
XL C/C++ for AIX Fix Pack 24 (September 2016 PTF) for 11.1
January 2011 PTF for XL C for AIX, V11.1
August 2011 PTF for XL C for AIX, V11.1
November 2011 PTF for XL C for AIX, V11.1
July 2012 PTF for XL C for AIX, V11.1
XL C for AIX Fix Pack 16 (November 2013 PTF) for 11.1
XL C for AIX Fix Pack 18 (May 2014 PTF) for 11.1
XL C for AIX Fix Pack 19 (August 2014 PTF) for 11.1
XL C for AIX Fix Pack 20 (November 2014 PTF) for 11.1
XL C for AIX Fix Pack 22 (September 2015 PTF) for 11.1

APAR status

• Closed as program error.

Error description

• When compiling a large program using -O3, the complile time
  drastically increases than compared to compiling t -O2 or
  without any optimizations.
  
  eg: When using -qphsinfo, the detailed compile time output can
  be observed:
  $xlC_r -qoptimize=3 -qphsinfo
  -qtmplparse=warn -q64 -qfuncsect -qrtti=all
  -qlanglvl=newexcp -qeh=v6 -qutf -qtabsize=4 -D__IBMCPP_TR1__
  -qtbtable=full -c -o BulkImport.o BulkImport.i -+
  
  Front End - Phase Ends;   8.405/  8.413
  IPA       - Phase Ends;  74.070/ 74.250
  W-TRANS   - Phase Ends;  10.480/ 10.490
  OPTIMIZ   - Phase Ends; 6636.230/6692.010
  REGALLO   - Phase Ends; 186.540/249.420
  AS        - Phase Ends;   0.130/  0.140
  IPA       - Phase Ends;  74.070/ 74.250
  $
  

Local fix

• N/A
  

Problem summary

• USERS AFFECTED:
  User compiling a large program with optimization may be
  affected by this issue.
  
  PROBLEM DESCRIPTION:
  The compile time problem was caused by the alias information
  generation for the function descriptor during a specific
  optimization within xlCcode.
  

Problem conclusion

• The compiler has been fixed to reduce some overheads in the
  computation of the aliasing of the function descriptor.
  

Temporary fix

Comments

APAR Information

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

  IZ83459

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

Fix information

• Fixed component name

  XL C FOR AIX

• Fixed component ID

  5724X1200

Applicable component levels