[turbofan] Add Symbol feedback to Equal/StrictEqual.

[turbofan] Add Symbol feedback to Equal/StrictEqual.

Introduce a new Symbol comparison feedback bit in the lattice and
collect that feedback on Equal/StrictEqual in Ignition. Utilize this
feedback in TurboFan by adding a dedicated CheckSymbol operator to
check for symbol inputs. This way we can optimize Symbol comparison
where TurboFan doesn't know anything statically about either side, or
abstract equality comparisons where TurboFan doesn't statically know
anything about one side.

BUG=v8:6278, v8:6344, v8:6423
R=jarin@chromium.org

Review-Url: https://codereview.chromium.org/2893263002
Cr-Commit-Position: refs/heads/master@{#45455}
Committed: https://chromium.googlesource.com/v8/v8/+/d9e432973b4d7d2fe7a8c9b465b83a6f34f566ef

[Benedikt Meurer, 2017-05-22 11:34:50]

The CQ bit was checked by bmeurer@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-05-22 11:35:00]

Dry run: CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[Jarin, 2017-05-22 11:49:07]

lgtm

[Benedikt Meurer, 2017-05-22 11:50:05]

The CQ bit was unchecked by bmeurer@chromium.org

[Benedikt Meurer, 2017-05-22 11:50:10]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2017-05-22 11:50:20]

CQ is trying da patch.

Follow status at:
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-05-22 12:07:41]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1495453810561050, "parent_rev":
"b5e610c19208ef854755eec67011ca7aff008bf4", "commit_rev":
"d9e432973b4d7d2fe7a8c9b465b83a6f34f566ef"}

[commit-bot: I haz the power, 2017-05-22 12:07:48]

Description was changed from

==========
[turbofan] Add Symbol feedback to Equal/StrictEqual.

Introduce a new Symbol comparison feedback bit in the lattice and
collect that feedback on Equal/StrictEqual in Ignition. Utilize this
feedback in TurboFan by adding a dedicated CheckSymbol operator to
check for symbol inputs. This way we can optimize Symbol comparison
where TurboFan doesn't know anything statically about either side, or
abstract equality comparisons where TurboFan doesn't statically know
anything about one side.

BUG=v8:6278,v8:6344,v8:6423
R=jarin@chromium.org
==========

to

==========
[turbofan] Add Symbol feedback to Equal/StrictEqual.

Introduce a new Symbol comparison feedback bit in the lattice and
collect that feedback on Equal/StrictEqual in Ignition. Utilize this
feedback in TurboFan by adding a dedicated CheckSymbol operator to
check for symbol inputs. This way we can optimize Symbol comparison
where TurboFan doesn't know anything statically about either side, or
abstract equality comparisons where TurboFan doesn't statically know
anything about one side.

BUG=v8:6278,v8:6344,v8:6423
R=jarin@chromium.org

Review-Url: https://codereview.chromium.org/2893263002
Cr-Commit-Position: refs/heads/master@{#45455}
Committed:
https://chromium.googlesource.com/v8/v8/+/d9e432973b4d7d2fe7a8c9b465b83a6f34f...
==========

[commit-bot: I haz the power, 2017-05-22 12:07:49]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/v8/v8/+/d9e432973b4d7d2fe7a8c9b465b83a6f34f...