The -ipo_c and -ipo_S options are useful for analyzing the effects of multifile IPO, or when experimenting with multifile IPO between modules that do not make up a complete program.
Use the -ipo_c option to optimize across files and produce an object file. This option performs optimizations as described for -ipo, but stops prior to the final link stage, leaving an optimized object file. The default name for this file is ipo_out.o.
Use the -ipo_S option to optimize across files and produce an assemblable file. This option performs optimizations as described for -ipo, but stops prior to the final link stage, leaving an optimized assemblable file. The default name for this file is ipo_out.s.
See also Inline Expansion of Functions.