[turbofan] Make FindFrameStateBefore handle dead paths.

[turbofan] Make FindFrameStateBefore handle dead paths.

This makes sure {NodeProperties::FindFrameStateBefore} can deal with
effect chains that are marked as dead. This can happen when reducers
looking for frame states run together with other reducers killing some
execution paths within the same reduction phase.

R=bmeurer@chromium.org
TEST=mjsunit/regress/regress-crbug-617567
BUG=chromium:617567, chromium:617224
Committed: https://crrev.com/826627d9fd0e452a423948536076027c2b22a49b
Cr-Commit-Position: refs/heads/master@{#36743}

[titzer, 2016-06-06 12:14:30]

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

[titzer, 2016-06-06 12:14:31]

lgtm

[Michael Starzinger, 2016-06-06 12:22:10]

The CQ bit was checked by mstarzinger@chromium.org

[commit-bot: I haz the power, 2016-06-06 12:22:15]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2041833002/1

[commit-bot: I haz the power, 2016-06-06 12:32:00]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-06-06 12:34:59]

Description was changed from

==========
[turbofan] Make FindFrameStateBefore handle dead paths.

This makes sure {NodeProperties::FindFrameStateBefore} can deal with
effect chains that are marked as dead. This can happen when reducers
looking for frame states run together with other reducers killing some
execution paths within the same reduction phase.

R=bmeurer@chromium.org
TEST=mjsunit/regress/regress-crbug-617567
BUG=chromium:617567,chromium:617224
==========

to

==========
[turbofan] Make FindFrameStateBefore handle dead paths.

This makes sure {NodeProperties::FindFrameStateBefore} can deal with
effect chains that are marked as dead. This can happen when reducers
looking for frame states run together with other reducers killing some
execution paths within the same reduction phase.

R=bmeurer@chromium.org
TEST=mjsunit/regress/regress-crbug-617567
BUG=chromium:617567,chromium:617224

Committed: https://crrev.com/826627d9fd0e452a423948536076027c2b22a49b
Cr-Commit-Position: refs/heads/master@{#36743}
==========

[commit-bot: I haz the power, 2016-06-06 12:35:00]

Patchset 1 (id:??) landed as
https://crrev.com/826627d9fd0e452a423948536076027c2b22a49b
Cr-Commit-Position: refs/heads/master@{#36743}