[turbofan] Improve lowering of ObjectIs<Type> somewhat.

[turbofan] Improve lowering of ObjectIs<Type> somewhat.

If we already know that the input to one of the ObjectIs<Type> nodes is
TaggedPointer, we don't need to perform the Smi check at runtime.

R=jarin@chromium.org

Committed: https://crrev.com/4fc4978cee0bb7ad2ae8681a67b7032eba6a7d11
Cr-Commit-Position: refs/heads/master@{#35368}

[Benedikt Meurer, 2016-04-09 17:55:17]

Hey Jaro,

Simple improvement, helps Richards.
Please take a look.

Thanks,
Benedikt

[Jarin, 2016-04-10 10:09:19]

lgtm

[Benedikt Meurer (Google), 2016-04-10 15:13:56]

The CQ bit was checked by bmeurer@google.com

[commit-bot: I haz the power, 2016-04-10 15:14:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1872143002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1872143002/1

[commit-bot: I haz the power, 2016-04-10 15:31:08]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-04-10 15:31:47]

Description was changed from

==========
[turbofan] Improve lowering of ObjectIs<Type> somewhat.

If we already know that the input to one of the ObjectIs<Type> nodes is
TaggedPointer, we don't need to perform the Smi check at runtime.

R=jarin@chromium.org
==========

to

==========
[turbofan] Improve lowering of ObjectIs<Type> somewhat.

If we already know that the input to one of the ObjectIs<Type> nodes is
TaggedPointer, we don't need to perform the Smi check at runtime.

R=jarin@chromium.org

Committed: https://crrev.com/4fc4978cee0bb7ad2ae8681a67b7032eba6a7d11
Cr-Commit-Position: refs/heads/master@{#35368}
==========

[commit-bot: I haz the power, 2016-04-10 15:31:48]

Patchset 1 (id:??) landed as
https://crrev.com/4fc4978cee0bb7ad2ae8681a67b7032eba6a7d11
Cr-Commit-Position: refs/heads/master@{#35368}

[Benedikt Meurer, 2016-04-16 19:00:35]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1893123002/ by bmeurer@chromium.org.

The reason for reverting is: Looking at types in ChangeLowering is generally
unsafe..