GCC have a many intresting options, that is not currently support CB.
Please, add these options to opt window.
-flto(link time codegeneration)
-Ofast(-O3 with --fash-math and other improvements)
-momit-leaf-frame-pointer(omit frame pointer from leaf functions)
-msse(using SSE instruction set) --- it's needed because in my test i found, that with -march=pentium3(mmx, sse) gcc produces bad code rather than i use -mmmx & -msse
... and many others, i can lead list of important options
Also there is a bug in codeblocks. If i type by myself option, that CB supports, to compiler options(for example, -O3) and click OK, then codeblocks removes it from compiler options and
does not add to compiler flags.
Also i'm tested and found, that it's need to add some compiler options to linker flags too. CB only adds -s to linker options, if i specify it in compiler flags. I think, codeblocks
should duplicate all the options from compiler command line to linker. There is no options, that linker say it's invalid. But in some cases it important to duplicate options to gcc linker.
Also there is vary bad situation with ICC compiler. I have ICC 12.
It doesn't support now options such as /QxK, /QxB, ... There is now similiar options like: /arch:IA32(uses mmx & sse), /arch:SSE2(uses SSE2) and so on.
Also sorry for my Eng, i'm Ru.