Hi, On 2011-06-06, at 4:59 PM, Dmitry Gorbachev wrote:
>> How does -Ofast increase size compared to -O3? > > I had in mind -Ofast or -O3 versus -Os (which is used by default when > building ReactOS). Now I realise you probably meant -- consider > replacing -O3 by -Ofast... Yes, I thought -O3 was the default on CMAKE builds. So I was recommending -Ofast instead of -O3, indeed. > > BTW, will it be possible to compile kernel-mode code and user-mode > code with different sets of options? Somebody might want to build > user-mode stuff with more optimization then it's allowed for the > kernel. In fact, with GCC 4.6.0 it's even possible to do this at the function-level. I'm not sure why you would want kernel code to be "smaller" instead of "faster" though -- on modern processors for cases like interrupts and such, large-but-correctly-aligned-and-optimized code is faster than less-bytes-per-instruction/opcode-packed code. ie: mov eax, [foo] add eax, 1 mov [foo], eax is faster than inc [foo] -- Best regards, Alex Ionescu > > _______________________________________________ > Ros-dev mailing list > [email protected] > http://www.reactos.org/mailman/listinfo/ros-dev _______________________________________________ Ros-dev mailing list [email protected] http://www.reactos.org/mailman/listinfo/ros-dev
