David Miller wrote:
From: Jeff Garzik <[EMAIL PROTECTED]>
Date: Fri, 21 Dec 2007 06:26:48 -0500
YOSHIFUJI Hideaki / 吉藤英明 wrote:
In article <[EMAIL PROTECTED]> (at Fri, 21 Dec 2007 07:03:58 +0100), Eric Dumazet
<[EMAIL PROTECTED]> 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.
Quite true -- thus it is a matter of taste to the programmer.
Not true, the code output does change, check your optimize-for-size
kernel config setting.
This was discussed and explained later in this thread, and I also
explained it to you on IRC Jeff ;-)
[looks]
For signed integers, this is true.
For unsigned integers, the code output is the same, regardless of
optimization setting.
Jeff
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