[turbofan] Keep the next bytecode liveness when analysing

[turbofan] Keep the next bytecode liveness when analysing

Since the majority of bytecodes have a next instruction, and we iterate
over the bytecodes backwards, we can keep the previous seen (i.e.
sequentially next) bytecode's liveness on a variable instead of looking
it up again.

Committed: https://crrev.com/9b5962720ac5b05e2b751ddb46bb892bf323f7e9
Cr-Commit-Position: refs/heads/master@{#41361}

[Leszek Swirski, 2016-11-29 13:00:53]

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

[commit-bot: I haz the power, 2016-11-29 13:01:01]

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, 2016-11-29 13:25:52]

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

[commit-bot: I haz the power, 2016-11-29 13:25:53]

Dry run: This issue passed the CQ dry run.

[Leszek Swirski, 2016-11-29 13:57:58]

leszeks@chromium.org changed reviewers:
+ jarin@chromium.org

[Leszek Swirski, 2016-11-29 13:57:58]

Hi Jaro,

Can you take a look at this? I think this is a no-brainer optimisation.

[Jarin, 2016-11-29 14:10:02]

lgtm

[Leszek Swirski, 2016-11-29 14:10:32]

The CQ bit was checked by leszeks@chromium.org

[commit-bot: I haz the power, 2016-11-29 14:10:34]

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, 2016-11-29 14:12:08]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1480428632902080, "parent_rev":
"13d01e318288f5e0e7dfc7f9ea51484cfd40d289", "commit_rev":
"90f8e412dd5b0ab7d5a0c367f5999d2f1bf09a17"}

[commit-bot: I haz the power, 2016-11-29 14:12:13]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-11-29 14:12:44]

Description was changed from

==========
[turbofan] Keep the next bytecode liveness when analysing

Since the majority of bytecodes have a next instruction, and we iterate
over the bytecodes backwards, we can keep the previous seen (i.e.
sequentially next) bytecode's liveness on a variable instead of looking
it up again.
==========

to

==========
[turbofan] Keep the next bytecode liveness when analysing

Since the majority of bytecodes have a next instruction, and we iterate
over the bytecodes backwards, we can keep the previous seen (i.e.
sequentially next) bytecode's liveness on a variable instead of looking
it up again.

Committed: https://crrev.com/9b5962720ac5b05e2b751ddb46bb892bf323f7e9
Cr-Commit-Position: refs/heads/master@{#41361}
==========

[commit-bot: I haz the power, 2016-11-29 14:12:44]

Patchset 1 (id:??) landed as
https://crrev.com/9b5962720ac5b05e2b751ddb46bb892bf323f7e9
Cr-Commit-Position: refs/heads/master@{#41361}