[turbofan] Don't eliminate FinishRegion nodes.

[turbofan] Don't eliminate FinishRegion nodes.

The way we use FinishRegion for transitioning stores makes them eligible
for elimination by TypedOptimization, which is unintended and removes
the atomicity of the transitioning stores. This is a quickfix to ensure
that we don't remove the FinishRegion nodes during TypedOptimization;
the real fix is probably to have separate region operators for value
(producing) regions (i.e. allocations) and for effect-only regions (i.e.
transitioning stores).

R=jarin@chromium.org
BUG=v8:5303
Committed: https://crrev.com/a45da58b41c3a5086c7001e598fecefa60ebae1b
Cr-Commit-Position: refs/heads/master@{#39033}

[Benedikt Meurer, 2016-08-31 03:25:53]

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

[commit-bot: I haz the power, 2016-08-31 03:26:00]

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

[Benedikt Meurer, 2016-08-31 03:26:29]

Hey Jaro,

Here's a quickfix for the FinishRegion issue. Afterwards the separation of
regions can indeed be a starter project.
Please take a look.

Thanks,
Benedikt

[commit-bot: I haz the power, 2016-08-31 04:01:53]

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

[commit-bot: I haz the power, 2016-08-31 04:01:55]

Dry run: This issue passed the CQ dry run.

[Jarin, 2016-08-31 05:45:32]

lgtm

[Benedikt Meurer, 2016-08-31 05:45:49]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2016-08-31 05:45:53]

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, 2016-08-31 05:49:26]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-08-31 05:50:05]

Description was changed from

==========
[turbofan] Don't eliminate FinishRegion nodes.

The way we use FinishRegion for transitioning stores makes them eligible
for elimination by TypedOptimization, which is unintended and removes
the atomicity of the transitioning stores. This is a quickfix to ensure
that we don't remove the FinishRegion nodes during TypedOptimization;
the real fix is probably to have separate region operators for value
(producing) regions (i.e. allocations) and for effect-only regions (i.e.
transitioning stores).

R=jarin@chromium.org
BUG=v8:5303
==========

to

==========
[turbofan] Don't eliminate FinishRegion nodes.

The way we use FinishRegion for transitioning stores makes them eligible
for elimination by TypedOptimization, which is unintended and removes
the atomicity of the transitioning stores. This is a quickfix to ensure
that we don't remove the FinishRegion nodes during TypedOptimization;
the real fix is probably to have separate region operators for value
(producing) regions (i.e. allocations) and for effect-only regions (i.e.
transitioning stores).

R=jarin@chromium.org
BUG=v8:5303

Committed: https://crrev.com/a45da58b41c3a5086c7001e598fecefa60ebae1b
Cr-Commit-Position: refs/heads/master@{#39033}
==========

[commit-bot: I haz the power, 2016-08-31 05:50:05]

Patchset 1 (id:??) landed as
https://crrev.com/a45da58b41c3a5086c7001e598fecefa60ebae1b
Cr-Commit-Position: refs/heads/master@{#39033}