Architecture and processor support

The -qarch and -qtune compiler options control the code generated by the compiler. These compiler options adjust the instructions, scheduling, and other optimizations to give the best performance for a specified target processor or range of processors.

New default setting for -qtune

The new default -qtune setting is:
  • -qtune=balanced

The -qtune=balanced suboption is new for this release, and becomes the default -qtune setting when certain -qarch settings are specified. Using -qtune=balanced instructs the compiler to tune generated code for optimal performance across a range of recent processor architectures, including POWER6™.

New support for POWER6 processors

XL C/C++ Version 9.0 expanded the list of -qarch and -qtune suboptions to support the newly-available POWER6 processors.

The following -qarch and -qtune options are now available:
  • -qarch=pwr6
  • -qarch=pwr6e
  • -qtune=pwr6