[turbofan] fix another divergence in escape analysis

[turbofan] fix another divergence in escape analysis

This divergence bug is very similar to the one fixed in https://codereview.chromium.org/2522253002/, this time it is an oscillation between a cleared field and a new phi node. The page http://www.sears.com/clothing-shoes-jewelry-clothing-men-s-clothing-men-s-jeans/b-1325287370?Brand=LEE&filterList=Brand&sortOption=UNITS_HIGH_TO_LOW allows for a reliable reproduction.

This fix makes sure that once a field that generated a phi gets cleared, it always stays cleared.

BUG=chromium:670202
R=bmeurer@chromium.org

Review-Url: https://codereview.chromium.org/2599793002
Cr-Commit-Position: refs/heads/master@{#41922}
Committed: https://chromium.googlesource.com/v8/v8/+/8435cc852672c504d5899cc2765c5b895e658efe

[Benedikt Meurer, 2016-12-22 13:56:16]

The CQ bit was checked by bmeurer@chromium.org

[Benedikt Meurer, 2016-12-22 13:56:16]

lgtm

Woohoo

[commit-bot: I haz the power, 2016-12-22 13:56:24]

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, 2016-12-22 14:21:25]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1482414976515670, "parent_rev":
"f73973092c780ba6c2c6988fce777472eb95a58f", "commit_rev":
"8435cc852672c504d5899cc2765c5b895e658efe"}

[commit-bot: I haz the power, 2016-12-22 14:21:31]

Description was changed from

==========
[turbofan] fix another divergence in escape analysis

This divergence bug is very similar to the one fixed in
https://codereview.chromium.org/2522253002/, this time it is an oscillation
between a cleared field and a new phi node. The page
http://www.sears.com/clothing-shoes-jewelry-clothing-men-s-clothing-men-s-jea...
allows for a reliable reproduction.

This fix makes sure that once a field that generated a phi gets cleared, it
always stays cleared.

BUG=chromium:670202

R=bmeurer@chromium.org
==========

to

==========
[turbofan] fix another divergence in escape analysis

This divergence bug is very similar to the one fixed in
https://codereview.chromium.org/2522253002/, this time it is an oscillation
between a cleared field and a new phi node. The page
http://www.sears.com/clothing-shoes-jewelry-clothing-men-s-clothing-men-s-jea...
allows for a reliable reproduction.

This fix makes sure that once a field that generated a phi gets cleared, it
always stays cleared.

BUG=chromium:670202

R=bmeurer@chromium.org

Review-Url: https://codereview.chromium.org/2599793002
Cr-Commit-Position: refs/heads/master@{#41922}
Committed:
https://chromium.googlesource.com/v8/v8/+/8435cc852672c504d5899cc2765c5b895e6...
==========

[commit-bot: I haz the power, 2016-12-22 14:21:32]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/v8/v8/+/8435cc852672c504d5899cc2765c5b895e6...

[Tobias Tebbi, 2017-01-03 09:36:08]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/2611623002/ by tebbi@chromium.org.

The reason for reverting is: Caused memory corruption.

BUG=chromium:676767.