Re: [TCP] IPV6 : Change a divide into a right shift in tcp_v6_send_ack()

In article [ref] (at Fri, 21 Dec 2007 07:03:58 +0100), Eric Dumazet [off-list ref] says:

Because tot_len is signed in tcp_v6_send_ack(), tot_len/4 forces compiler
to emit an integer divide, while we can help it to use a right shift,
less expensive.

Are you really sure?
At least, gcc-4.1.2-20061115 (debian) does not make any difference.

And, IMHO, because shift for signed variable is fragile, so we should
avoid using it.

--yoshfuji