Fix UBSan errors (left shift of negative value)

Fix UBSan errors (left shift of negative value)

I've settled on replacing x << n with x * (1 << n); this gets rid of
the "left shift of negative value" warning, but will still trigger
undefined behavior if the multiplication overflows. It also still
looks like a left shift, which is good for the readability of the
fixed-point code.

(The compiler is smart enough to recognize that the
multiplication+shift is just a shift, for both variable and constant
shift amounts, so the generated code should not change.)

BUG=chromium:603491
Committed: https://crrev.com/64208e55232fba0a81b846091197cc68a431ee77
Cr-Commit-Position: refs/heads/master@{#12845}

[kwiberg-webrtc, 2016-05-18 11:47:01]

Patchset #1 (id:1) has been deleted

[kwiberg-webrtc, 2016-05-18 13:29:10]

kwiberg@webrtc.org changed reviewers:
+ tina.legrand@webrtc.org

[tlegrand-webrtc, 2016-05-20 10:39:30]

LGTM

[kwiberg-webrtc, 2016-05-20 11:34:55]

The CQ bit was checked by kwiberg@webrtc.org

[commit-bot: I haz the power, 2016-05-20 11:35:07]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1989803002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1989803002/20001

[commit-bot: I haz the power, 2016-05-20 13:35:33]

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

[commit-bot: I haz the power, 2016-05-20 13:35:34]

Try jobs failed on following builders:
  android_arm64_rel on tryserver.webrtc (JOB_TIMED_OUT, no build URL)
  android_rel on tryserver.webrtc (JOB_TIMED_OUT, no build URL)

[kwiberg-webrtc, 2016-05-23 08:24:46]

The CQ bit was checked by kwiberg@webrtc.org

[commit-bot: I haz the power, 2016-05-23 08:24:52]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1989803002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1989803002/20001

[commit-bot: I haz the power, 2016-05-23 10:28:33]

Committed patchset #1 (id:20001)

[commit-bot: I haz the power, 2016-05-23 10:28:44]

Description was changed from

==========
Fix UBSan errors (left shift of negative value)

I've settled on replacing x << n with x * (1 << n); this gets rid of
the "left shift of negative value" warning, but will still trigger
undefined behavior if the multiplication overflows. It also still
looks like a left shift, which is good for the readability of the
fixed-point code.

(The compiler is smart enough to recognize that the
multiplication+shift is just a shift, for both variable and constant
shift amounts, so the generated code should not change.)

BUG=chromium:603491
==========

to

==========
Fix UBSan errors (left shift of negative value)

I've settled on replacing x << n with x * (1 << n); this gets rid of
the "left shift of negative value" warning, but will still trigger
undefined behavior if the multiplication overflows. It also still
looks like a left shift, which is good for the readability of the
fixed-point code.

(The compiler is smart enough to recognize that the
multiplication+shift is just a shift, for both variable and constant
shift amounts, so the generated code should not change.)

BUG=chromium:603491

Committed: https://crrev.com/64208e55232fba0a81b846091197cc68a431ee77
Cr-Commit-Position: refs/heads/master@{#12845}
==========

[commit-bot: I haz the power, 2016-05-23 10:28:46]

Patchset 1 (id:??) landed as
https://crrev.com/64208e55232fba0a81b846091197cc68a431ee77
Cr-Commit-Position: refs/heads/master@{#12845}