[turbofan] Introduce TruncateTaggedPointerToBit operator.

[turbofan] Introduce TruncateTaggedPointerToBit operator.

Oftentimes we can avoid the Smi check for ToBoolean truncations, since
we already know that the input is always going to be a HeapObject. So
introduce a dedicated TruncateTaggedPointerToBit operator, which uses
the fact that the input is known to be a HeapObject.

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

Review-Url: https://codereview.chromium.org/2738483002
Cr-Commit-Position: refs/heads/master@{#43629}
Committed: https://chromium.googlesource.com/v8/v8/+/95d808670e37d660f9eb8d76546587c8fe52167d

[Benedikt Meurer, 2017-03-06 19:23:16]

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

[commit-bot: I haz the power, 2017-03-06 19:23:24]

Dry run: 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, 2017-03-06 19:48:54]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-03-06 19:48:55]

Dry run: This issue passed the CQ dry run.

[Jarin, 2017-03-07 10:08:13]

lgtm, even though I am getting worried about this piling up of code here without
any indication of benefit.

[Benedikt Meurer, 2017-03-07 10:09:27]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2017-03-07 10:09:37]

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, 2017-03-07 10:11:18]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1488881367077080, "parent_rev":
"f3d0bda8019bcf656f9c8a7d75473c32b1e56dd9", "commit_rev":
"95d808670e37d660f9eb8d76546587c8fe52167d"}

[commit-bot: I haz the power, 2017-03-07 10:11:22]

Description was changed from

==========
[turbofan] Introduce TruncateTaggedPointerToBit operator.

Oftentimes we can avoid the Smi check for ToBoolean truncations, since
we already know that the input is always going to be a HeapObject. So
introduce a dedicated TruncateTaggedPointerToBit operator, which uses
the fact that the input is known to be a HeapObject.

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

to

==========
[turbofan] Introduce TruncateTaggedPointerToBit operator.

Oftentimes we can avoid the Smi check for ToBoolean truncations, since
we already know that the input is always going to be a HeapObject. So
introduce a dedicated TruncateTaggedPointerToBit operator, which uses
the fact that the input is known to be a HeapObject.

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

Review-Url: https://codereview.chromium.org/2738483002
Cr-Commit-Position: refs/heads/master@{#43629}
Committed:
https://chromium.googlesource.com/v8/v8/+/95d808670e37d660f9eb8d76546587c8fe5...
==========

[commit-bot: I haz the power, 2017-03-07 10:11:23]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/v8/v8/+/95d808670e37d660f9eb8d76546587c8fe5...