[turbofan] Eliminate unnecessary hole to undefined conversion.

[turbofan] Eliminate unnecessary hole to undefined conversion.

Add simplified operator reduction rule that reduces

  CheckedTaggedSignedToInt32(ConvertTaggedHoleToUndefined(x))

to

  CheckedTaggedSignedToInt32(x)

which avoids the unnecessary hole to undefined conversion, as the check
operation will fail equally on either hole or undefined.

BUG=v8:5267
R=jarin@chromium.org

Committed: https://crrev.com/cb0de11d800ffb0aa6ca26b54e97fd0f8b93d558
Cr-Commit-Position: refs/heads/master@{#39863}

[Benedikt Meurer, 2016-09-29 12:24:04]

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

[commit-bot: I haz the power, 2016-09-29 12:24:07]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[epertoso, 2016-09-29 12:31:17]

epertoso@chromium.org changed reviewers:
+ epertoso@chromium.org

[epertoso, 2016-09-29 12:31:18]

lgtm

[Jarin, 2016-09-29 12:31:54]

lgtm

[Benedikt Meurer, 2016-09-29 12:32:18]

The CQ bit was unchecked by bmeurer@chromium.org

[Benedikt Meurer, 2016-09-29 12:32:27]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2016-09-29 12:32:34]

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, 2016-09-29 12:51:51]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-09-29 12:52:11]

Description was changed from

==========
[turbofan] Eliminate unnecessary hole to undefined conversion.

Add simplified operator reduction rule that reduces

  CheckedTaggedSignedToInt32(ConvertTaggedHoleToUndefined(x))

to

  CheckedTaggedSignedToInt32(x)

which avoids the unnecessary hole to undefined conversion, as the check
operation will fail equally on either hole or undefined.

BUG=v8:5267
R=jarin@chromium.org
==========

to

==========
[turbofan] Eliminate unnecessary hole to undefined conversion.

Add simplified operator reduction rule that reduces

  CheckedTaggedSignedToInt32(ConvertTaggedHoleToUndefined(x))

to

  CheckedTaggedSignedToInt32(x)

which avoids the unnecessary hole to undefined conversion, as the check
operation will fail equally on either hole or undefined.

BUG=v8:5267
R=jarin@chromium.org

Committed: https://crrev.com/cb0de11d800ffb0aa6ca26b54e97fd0f8b93d558
Cr-Commit-Position: refs/heads/master@{#39863}
==========

[commit-bot: I haz the power, 2016-09-29 12:52:12]

Patchset 1 (id:??) landed as
https://crrev.com/cb0de11d800ffb0aa6ca26b54e97fd0f8b93d558
Cr-Commit-Position: refs/heads/master@{#39863}