Avoid left-shifting negative values in a number of places

Avoid left-shifting negative values in a number of places

This is undefined behavior, according to specification.

BUG=chromium:661133
Committed: https://crrev.com/79dfdadbc861a56596a42ba9f40c8bcbf30e4d75
Cr-Commit-Position: refs/heads/master@{#15078}

[hlundin-webrtc, 2016-11-15 07:21:22]

henrik.lundin@webrtc.org changed reviewers:
+ kwiberg@webrtc.org

[hlundin-webrtc, 2016-11-15 07:21:22]

PTAL

[hlundin-webrtc, 2016-11-15 07:49:31]

The CQ bit was checked by henrik.lundin@webrtc.org to run a CQ dry run

[commit-bot: I haz the power, 2016-11-15 07:49:40]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.webrtc.org/...

[commit-bot: I haz the power, 2016-11-15 08:09:43]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-15 08:09:44]

Dry run: This issue passed the CQ dry run.

[hlundin-webrtc, 2016-11-15 08:21:23]

henrik.lundin@webrtc.org changed reviewers:
+ ivoc@webrtc.org

[hlundin-webrtc, 2016-11-15 08:21:24]

Ivo, PTAL.

[ivoc, 2016-11-15 09:39:08]

LGTM, but I think that right-shifts of negative numbers (happens many times in
these files) may also be undefined behavior.

[hlundin-webrtc, 2016-11-15 09:44:04]

On 2016/11/15 09:39:08, ivoc wrote:
> LGTM, but I think that right-shifts of negative numbers (happens many times in
> these files) may also be undefined behavior.

Acknowledged.

Thanks!

[hlundin-webrtc, 2016-11-15 09:44:12]

The CQ bit was checked by henrik.lundin@webrtc.org

[commit-bot: I haz the power, 2016-11-15 09:44:19]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.webrtc.org/...

[commit-bot: I haz the power, 2016-11-15 09:45:55]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-11-15 09:46:04]

Description was changed from

==========
Avoid left-shifting negative values in a number of places

This is undefined behavior, according to specification.

BUG=chromium:661133
==========

to

==========
Avoid left-shifting negative values in a number of places

This is undefined behavior, according to specification.

BUG=chromium:661133

Committed: https://crrev.com/79dfdadbc861a56596a42ba9f40c8bcbf30e4d75
Cr-Commit-Position: refs/heads/master@{#15078}
==========

[commit-bot: I haz the power, 2016-11-15 09:46:05]

Patchset 1 (id:??) landed as
https://crrev.com/79dfdadbc861a56596a42ba9f40c8bcbf30e4d75
Cr-Commit-Position: refs/heads/master@{#15078}

[kwiberg-webrtc, 2016-11-15 13:26:46]

On 2016/11/15 09:44:04, hlundin-webrtc wrote:
> On 2016/11/15 09:39:08, ivoc wrote:
> > LGTM, but I think that right-shifts of negative numbers (happens many times
in
> > these files) may also be undefined behavior.
> 
> Acknowledged.

I think that's implementation-defined, not undefined. And every 2's complement
implementation (i.e., pretty much all of them) will probably do the obvious
thing.

[ivoc, 2016-11-15 13:41:42]

On 2016/11/15 13:26:46, kwiberg-webrtc wrote:
> On 2016/11/15 09:44:04, hlundin-webrtc wrote:
> > On 2016/11/15 09:39:08, ivoc wrote:
> > > LGTM, but I think that right-shifts of negative numbers (happens many
times
> in
> > > these files) may also be undefined behavior.
> > 
> > Acknowledged.
> 
> I think that's implementation-defined, not undefined. And every 2's complement
> implementation (i.e., pretty much all of them) will probably do the obvious
> thing.

Would it be a good idea to make a unit test for this?