IV31756: APPLICATION SEGFAULT AT -O3

November 2012 PTF for XL C for AIX, V12.1
November 2012 PTF for XL C/C++ for AIX, V12.1
March 2013 PTF for XL C for AIX, V12.1
March 2013 PTF for XL C/C++ for AIX, V12.1

APAR status

• Closed as program error.

Error description

• When compiling a large application with -O3, the resulting
  binary segfaults at runtime. The issue appears to be related to
  the -O3 optimization level; as when decresing the optimization
  to -O2 avoid the issue.
  

Local fix

• Use -O2 instead of -O3 to avoid the issue.
  

Problem summary

• USERS AFFECTED:
  Users who compile at PPC 64 bit and at -O3 can be affected by
  this issue.
  
  PROBLEM DESCRIPTION:
  The max and min builtin functions for unsigned 32 bit quantities
  fails for expressions that have non zero values in the upper
  bits.
  

Problem conclusion

• The compiler has been fixed by cleaning the upper bits of the
  expression before generating the code sequence for unsigned 32
  bit min and max when -q64 is specified.
  

Temporary fix

Comments

APAR Information

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

  LI77090

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

Fix information

• Fixed component name

  XL C FOR AIX

• Fixed component ID

  5725C7100

Applicable component levels

• RC10 PSN U856101

     UP06/09/13 C