Why is WPO(whole-program optimization) not doing any improvements in my program size? (FPC 2.4.0)

Question

I use FPC 2.4.0 for WinXP(binary from the official page), also tryed with same version but compiled from source on my comp. I put something like this:

I:\pascal\fpc-2.4.0.source\fpc-2.4.0\compiler\ppc386 -FWserver-1.wpo -OWsymbolliveness -CX -XX -Xs- -al -Os -oServer1.o Server
I:\pascal\fpc-2.4.0.source\fpc-2.4.0\compiler\ppc386 -FWserver-2.wpo -OWsymbolliveness -Fwserver-1.wpo -Owsymbolliveness -CX -XX -Xs- -al -Os -oServer2.o Server
..(up to 100 times)

but always same .wpo files, and same .o sizes(.s, assembly files change intermittently)

I also not(through compiler messages), that not used variables are still alive. Also tryed -OWall -owall What am i doing wrong?

Answer 1

Make the second one -Fw and -Ow (lowercase second letter) as in the documentation for WPO

http://wiki.freepascal.org/Whole_Program_Optimization