Cloning within a single source file

Cloning replaces a call to a routine by calling a clone of that routine. The clone is optimized differently than the original routine.

Cloning can expose additional opportunities for interprocedural optimization. At +O3, cloning is performed within a file, and at +O4, cloning is performed across files. Cloning is enabled by default, and is disabled by specifying the +Onoinline command-line option.