bpf, x64: save several bytes when mul dest is r0/r3 anyway

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Instead of unconditionally performing push/pop on rax/rdx
in case of multiplication, we can save a few bytes in case
of dest register being either BPF r0 (rax) or r3 (rdx)
since the result is written in there anyway.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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Daniel Borkmann 2018-02-24 01:08:00 +01:00 • committed by Alexei Starovoitov

parent 6fe8b9c1f4

commit d806a0cf2a

1 changed files with 11 additions and 10 deletions

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arch/x86/net/bpf_jit_comp.c

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