Port the __SSE2__ code to Visual C++.

Port the __SSE2__ code to Visual C++.

R=thakis@chromium.org
BUG=none

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=282773

[wtc, 2014-07-09 22:51:52]

https://codereview.chromium.org/383543003/diff/1/net/tools/balsa/balsa_frame.cc
File net/tools/balsa/balsa_frame.cc (right):

https://codereview.chromium.org/383543003/diff/1/net/tools/balsa/balsa_frame....
net/tools/balsa/balsa_frame.cc:7: #if !defined(__SSE2__) && _M_IX86_FP == 2

_M_IX86_FP is 2 if the /arch:SSE2 compiler option is used. See
http://msdn.microsoft.com/en-us/library/b0084kay.aspx

https://codereview.chromium.org/383543003/diff/1/net/tools/balsa/balsa_frame....
net/tools/balsa/balsa_frame.cc:40: return _BitScanForward(&index, i) ? index + 1
: 0;

For ffs(), the index of the least significant bit is 1. For _BitScanForward, it
is 0. So we need to add 1 to |index|.

https://codereview.chromium.org/383543003/diff/1/net/tools/balsa/balsa_frame....
net/tools/balsa/balsa_frame.cc:519: const __m128i colons = _mm_set1_epi8(':');

Visual C++ doesn't have the __v16qi type. I think the new code is better anyway.

[Nico, 2014-07-09 22:57:19]

How about you just delete the  #if __SSE2__ blocks? That makes the code shorter,
and it's not performance-critical.

[wtc, 2014-07-09 23:02:38]

This file is shared with the internal server code, so it is better to minimize
the differences. I think the _mm_set1_epi8 changes are good and worth merging
back to the internal repository.

I am also willing to solve the problem by changing

  #if __SSE2__

to

  #if __SSE2__ && defined(__GNUC__)

or

  #if __SSE2__ && defined(__linux__)

Please let me know which solution you prefer. Thanks.

[Nico, 2014-07-09 23:17:33]

If speed is important for the internal server code, this lgtm. Else I'd delete
it there too :-)

Thanks!

[wtc, 2014-07-11 19:53:06]

The CQ bit was checked by wtc@chromium.org

[commit-bot: I haz the power, 2014-07-11 19:54:05]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/wtc@chromium.org/383543003/20001

[commit-bot: I haz the power, 2014-07-12 01:33:07]

Change committed as 282773