shyokou: this is not exactly what Git was refering to. IDA introduced that feature because some compilers (optimization?) break a single function into several chunks and do not place them in a contiguous area. Sometimes these chunks are re-used by more than one function.

It is a function of IDA to actually recognize the chunks - earlier versions did not - but it is the compiler/linker that actually generates code that way. Look at most of Windows' DLL (kernel32, ntdll, ...) for live examples.