[turbofan] Also eliminate branches during load elimination.

[turbofan] Also eliminate branches during load elimination.

Also run the BranchElimination (plus CommonOperatorReducer and the
DeadCodeElimination) during the load elimination phase, so we can
elminate some Phi nodes early on that would otherwise confuse the
truncation analysis and/or representation selection, i.e. if there's a
branch that is never taken, that would yield undefined, we'd have to
choose tagged representation for the Phi, even if the always taken
branch yields an integer.

R=epertoso@chromium.org
BUG=v8:4930, v8:5141
Committed: https://crrev.com/14e2bcda857ba7d2307f0514cccb76b496721369
Cr-Commit-Position: refs/heads/master@{#38088}

[Benedikt Meurer, 2016-07-27 09:02:21]

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

[commit-bot: I haz the power, 2016-07-27 09:02:29]

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

[Benedikt Meurer, 2016-07-27 09:03:26]

Hey Enrico,

Here's a simple improvement for the pipeline.
Please take a look.

Thanks,
Benedikt

[epertoso, 2016-07-27 09:04:54]

lgtm

Nice.

[Benedikt Meurer, 2016-07-27 09:05:03]

The CQ bit was unchecked by bmeurer@chromium.org

[Benedikt Meurer, 2016-07-27 09:05:07]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2016-07-27 09:05:09]

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, 2016-07-27 09:25:09]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-07-27 09:29:02]

Description was changed from

==========
[turbofan] Also eliminate branches during load elimination.

Also run the BranchElimination (plus CommonOperatorReducer and the
DeadCodeElimination) during the load elimination phase, so we can
elminate some Phi nodes early on that would otherwise confuse the
truncation analysis and/or representation selection, i.e. if there's a
branch that is never taken, that would yield undefined, we'd have to
choose tagged representation for the Phi, even if the always taken
branch yields an integer.

R=epertoso@chromium.org
BUG=v8:4930,v8:5141
==========

to

==========
[turbofan] Also eliminate branches during load elimination.

Also run the BranchElimination (plus CommonOperatorReducer and the
DeadCodeElimination) during the load elimination phase, so we can
elminate some Phi nodes early on that would otherwise confuse the
truncation analysis and/or representation selection, i.e. if there's a
branch that is never taken, that would yield undefined, we'd have to
choose tagged representation for the Phi, even if the always taken
branch yields an integer.

R=epertoso@chromium.org
BUG=v8:4930,v8:5141

Committed: https://crrev.com/14e2bcda857ba7d2307f0514cccb76b496721369
Cr-Commit-Position: refs/heads/master@{#38088}
==========

[commit-bot: I haz the power, 2016-07-27 09:29:03]

Patchset 1 (id:??) landed as
https://crrev.com/14e2bcda857ba7d2307f0514cccb76b496721369
Cr-Commit-Position: refs/heads/master@{#38088}