IZ94357: COMPILING WITH IPA LEADS TO INCORRECT OUTPUT

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
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

• The following test case demonstrates the inocorrect output:
  
  $cat test.c
  #include <stdio.h>
  
  int c;
  int cia();
  int check1();
  int check2();
  
  int foo() {
    unsigned g1=0, g2=0;
  
    if (check1()) { g1=1;}
    if (check2()) { g2=1;}
  
    unsigned char f1 = cia();
  
    if ((( (c?1:0) || g1 || g2) && (f1 ))) return 1;
    return 0;
  }
  
  
  int cia() { return 1; }
  int check1() { return 0;}
  int check2() { return 0;}
  
  int main() {
    c=1;
    printf("foo =  %d\n", foo());
  
    return 0;
  }
  
  ======ACTUAL OUTPUT:
  $xlc -+ test.c -q64 -qhot -qlist -qnoinline ; ./a.out
  foo =  0
  $
  
  ======EXPECTED OUTPUT:
  $./a.out
  foo =  1
  

Local fix

• n/a
  

Problem summary

• USERS AFFECTED:
  Users compiling the applications with ipa maybe affected by
  this issue.
  
  PROBLEM DESCRIPTION:
  A specific internal branching optimization was not merging the
  branches correctly while handling the first jump label.
  

Problem conclusion

• The fix was to check if there is any jump to the label from
  outside of the predicate group when grouping the predicates
  with branch collapsing.
  

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:

  IZ97868 LI76135 LI76215 LI76237 IV02131 LI76380 LI76396

Fix information

• Fixed component name

  XL C FOR AIX

• Fixed component ID

  5724X1200

Applicable component levels