abstract:Interprocedural optimization (IPO) is a collection of compiler techniques used in computer programming to improve performance in programs containing many frequently used functions of small or medium length. IPO differs from other compiler optimization because it analyzes the entire program; other optimizations look at only a single function, or even a single block of code.
Stepping up to the -o4optimizationflag will buy incremental performance derived from chip-specificoptimizations, interproceduralanalysis, andhigh-ordertransformationroutines.