[crankshaft] Properly optimize strict equality with constants.

[crankshaft] Properly optimize strict equality with constants.

For values with canonical representation (i.e. not Number, Simd128Value
or Number) we can turn a strict equality comparison to a direct pointer
comparison. This removes the weird performance cliff when using a null
or undefined constant instead of the literals.

R=jarin@chromium.org
BUG=v8:5042
Committed: https://crrev.com/1f51868401a61b2fa19798e866a5a184e0226948
Cr-Commit-Position: refs/heads/master@{#36612}

[Benedikt Meurer, 2016-05-31 11:30:27]

Hey Jaro,

Quick fix for the strict equality with know compile time constant issue.
Please take a look.

Thanks,
Benedikt

[Jarin, 2016-05-31 11:35:24]

lgtm

[Benedikt Meurer, 2016-05-31 11:35:26]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2016-05-31 11:35:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2027603002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/2027603002/1

[commit-bot: I haz the power, 2016-05-31 11:58:53]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-05-31 11:59:18]

Description was changed from

==========
[crankshaft] Properly optimize strict equality with constants.

For values with canonical representation (i.e. not Number, Simd128Value
or Number) we can turn a strict equality comparison to a direct pointer
comparison. This removes the weird performance cliff when using a null
or undefined constant instead of the literals.

R=jarin@chromium.org
BUG=v8:5042
==========

to

==========
[crankshaft] Properly optimize strict equality with constants.

For values with canonical representation (i.e. not Number, Simd128Value
or Number) we can turn a strict equality comparison to a direct pointer
comparison. This removes the weird performance cliff when using a null
or undefined constant instead of the literals.

R=jarin@chromium.org
BUG=v8:5042

Committed: https://crrev.com/1f51868401a61b2fa19798e866a5a184e0226948
Cr-Commit-Position: refs/heads/master@{#36612}
==========

[commit-bot: I haz the power, 2016-05-31 11:59:18]

Patchset 1 (id:??) landed as
https://crrev.com/1f51868401a61b2fa19798e866a5a184e0226948
Cr-Commit-Position: refs/heads/master@{#36612}