On Thu, Dec 4, 2014 at 3:00 PM, Joe Perches <j...@perches.com> wrote: > Use the (1 << reg) & mask trick to reduce code size. > > x86-64 size difference -O2 without profiling for various > gcc versions: > > $ size arch/x86/net/bpf_jit_comp.o* > text data bss dec hex filename > 9266 4 0 9270 2436 arch/x86/net/bpf_jit_comp.o.4.4.new > 10042 4 0 10046 273e arch/x86/net/bpf_jit_comp.o.4.4.old > 9109 4 0 9113 2399 arch/x86/net/bpf_jit_comp.o.4.6.new > 9717 4 0 9721 25f9 arch/x86/net/bpf_jit_comp.o.4.6.old > 8789 4 0 8793 2259 arch/x86/net/bpf_jit_comp.o.4.7.new > 10245 4 0 10249 2809 arch/x86/net/bpf_jit_comp.o.4.7.old > 9671 4 0 9675 25cb arch/x86/net/bpf_jit_comp.o.4.9.new > 10679 4 0 10683 29bb arch/x86/net/bpf_jit_comp.o.4.9.old > > Signed-off-by: Joe Perches <j...@perches.com>
probably it was worth noting in comment that reg is 4-bit value and AUX_REG==12, so it won't overflow. Dave, it's for net-next of course. Suggested-by: Alexei Starovoitov <a...@plumgrid.com> Tested-by: Alexei Starovoitov <a...@plumgrid.com> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
