Re: [PATCH] x86: bpf_jit_comp: Reduce is_ereg() code size

From: Eric Dumazet
Date: Thu Dec 04 2014 - 18:14:59 EST


On Thu, 2014-12-04 at 15:00 -0800, Joe Perches wrote:
> Use the (1 << reg) & mask trick to reduce code size.
>
> x86-64 size difference -O2 without profiling for various
> gcc versions:

>
> Signed-off-by: Joe Perches <joe@xxxxxxxxxxx>
> ---
>
> compiled, untested by me, but per Alexei Starovoitov this passes
> the test_bpf suite

Really, the root cause of this is the 'inline' abuse in non fast paths
for non trivial functions.


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