On Fri, Oct 1, 2021 at 8:56 PM Jie Meng <jmeng@xxxxxx> wrote: > > Instead of unconditionally performing push/pop on rax/rdx in case of > division/modulo, 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. > > Also, we do not need to copy src to r11 unless src is either rax, rdx > or an immediate. > > For example, before the patch: > 22: push %rax > 23: push %rdx > 24: mov %rsi,%r11 > 27: xor %edx,%edx > 29: div %r11 > 2c: mov %rax,%r11 > 2f: pop %rdx > 30: pop %rax > 31: mov %r11,%rax > 34: leaveq > 35: retq > > After: > 22: push %rdx > 23: xor %edx,%edx > 25: div %rsi > 28: pop %rdx > 29: leaveq > 2a: retq > > Signed-off-by: Jie Meng <jmeng@xxxxxx> Applied. Thanks
