[for-in] Sanitize for-in optimizations and fix bailout points.

[for-in] Sanitize for-in optimizations and fix bailout points.

The PrepareId bailout location was used incorrectly in Crankshaft and,
as it turns out, is not required anyway (once you do it right). Also
there was some premature optimization going on with the CheckEnumCache
(trying to load null from roots only once), plus we can be smarter about
the null/undefined check anyway.

The idea behind this changes is to prepare unification of the two
different ForInPrepare implementations that we now have, with the end
result being that we only use the new implementation that was recently
added for the interpreter.

R=jarin@chromium.org
BUG=v8:3650
LOG=n

Committed: https://crrev.com/f48bf12f5ea99a9d01d390c0c7f51dc85a87f1cd
Cr-Commit-Position: refs/heads/master@{#33426}

[Benedikt Meurer, 2016-01-21 08:09:11]

Hey Jaro,

Here's the first set of changes to for-in. Please appreciate the initial
awesomefication. :-)
Please take a look.

Thanks,
Benedikt

[Jarin, 2016-01-21 08:41:03]

lgtm

[Benedikt Meurer, 2016-01-21 08:42:07]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2016-01-21 08:42:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1618613002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1618613002/1

[commit-bot: I haz the power, 2016-01-21 08:43:52]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-01-21 08:44:25]

Description was changed from

==========
[for-in] Sanitize for-in optimizations and fix bailout points.

The PrepareId bailout location was used incorrectly in Crankshaft and,
as it turns out, is not required anyway (once you do it right). Also
there was some premature optimization going on with the CheckEnumCache
(trying to load null from roots only once), plus we can be smarter about
the null/undefined check anyway.

The idea behind this changes is to prepare unification of the two
different ForInPrepare implementations that we now have, with the end
result being that we only use the new implementation that was recently
added for the interpreter.

R=jarin@chromium.org
BUG=v8:3650
LOG=n
==========

to

==========
[for-in] Sanitize for-in optimizations and fix bailout points.

The PrepareId bailout location was used incorrectly in Crankshaft and,
as it turns out, is not required anyway (once you do it right). Also
there was some premature optimization going on with the CheckEnumCache
(trying to load null from roots only once), plus we can be smarter about
the null/undefined check anyway.

The idea behind this changes is to prepare unification of the two
different ForInPrepare implementations that we now have, with the end
result being that we only use the new implementation that was recently
added for the interpreter.

R=jarin@chromium.org
BUG=v8:3650
LOG=n

Committed: https://crrev.com/f48bf12f5ea99a9d01d390c0c7f51dc85a87f1cd
Cr-Commit-Position: refs/heads/master@{#33426}
==========

[commit-bot: I haz the power, 2016-01-21 08:44:26]

Patchset 1 (id:??) landed as
https://crrev.com/f48bf12f5ea99a9d01d390c0c7f51dc85a87f1cd
Cr-Commit-Position: refs/heads/master@{#33426}