Colin wrote: > Julien Cayzac wrote: > >> On 5/24/05, Robert Crawford <[EMAIL PROTECTED]> wrote: >> >> >>> For what it's worth, according to man gcc, -O2 turns on >>> -funit-at-a-time. >>> >> >> >> Yup. Too bad every single Makefile in the world compiles c/c++ source >> files one by one :-/ >> >> > Wouldn't MAKEOPTS set to at least -j2 attempt to compile in parallel? >
How is that supposed to help -funit-at-a-time? From "info gcc": ---- The compiler performs optimization based on the knowledge it has of the program. Using the `-funit-at-a-time' flag will allow the compiler to consider information gained from later functions in the file when compiling a function. Compiling multiple files at once to a single output file (and using `-funit-at-a-time') will allow the compiler to use information gained from all of the files when compiling each of them. ---- So -funit-at-a-time performs best when multiple C/C++ files are compiled by a single invocation of GCC. As Julien said, no makefiles in use today (AFAIK) support this. -Richard -- [email protected] mailing list
