[turbofan] second attempt to fix second divergence in escape analysis

[turbofan] second attempt to fix second divergence in escape analysis

The previous patch for this bug (https://codereview.chromium.org/2599793002/) was wrong because it changed the behavior of isCreatedPhi() in an incompatible way. The actual source of the bug is that escape analysis propagates information along cycles without considering the previous analysis value. This fix makes sure that if a previous merge cleared a field, then it stays cleared.

R=bmeurer@chromium.org

BUG=chromium:670202
Review-Url: https://codereview.chromium.org/2610703002
Cr-Commit-Position: refs/heads/master@{#42045}
Committed: https://chromium.googlesource.com/v8/v8/+/199af0abb2bd2749673175e30389f9371041f737

[Benedikt Meurer, 2017-01-03 18:18:31]

lgtm

[Tobias Tebbi, 2017-01-03 18:56:46]

The CQ bit was checked by tebbi@chromium.org

[commit-bot: I haz the power, 2017-01-03 18:56:55]

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, 2017-01-03 19:21:55]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1483469806928900, "parent_rev":
"d75023f3a1f24498b05c361a62a7513e0918edcb", "commit_rev":
"199af0abb2bd2749673175e30389f9371041f737"}

[commit-bot: I haz the power, 2017-01-03 19:22:00]

Description was changed from

==========
[turbofan] second attempt to fix second divergence in escape analysis

The previous patch for this bug (https://codereview.chromium.org/2599793002/)
was wrong because it changed the behavior of isCreatedPhi() in an incompatible
way. The actual source of the bug is that escape analysis propagates information
along cycles without considering the previous analysis value. This fix makes
sure that if a previous merge cleared a field, then it stays cleared.

R=bmeurer@chromium.org

BUG=chromium:670202
==========

to

==========
[turbofan] second attempt to fix second divergence in escape analysis

The previous patch for this bug (https://codereview.chromium.org/2599793002/)
was wrong because it changed the behavior of isCreatedPhi() in an incompatible
way. The actual source of the bug is that escape analysis propagates information
along cycles without considering the previous analysis value. This fix makes
sure that if a previous merge cleared a field, then it stays cleared.

R=bmeurer@chromium.org

BUG=chromium:670202

Review-Url: https://codereview.chromium.org/2610703002
Cr-Commit-Position: refs/heads/master@{#42045}
Committed:
https://chromium.googlesource.com/v8/v8/+/199af0abb2bd2749673175e30389f937104...
==========

[commit-bot: I haz the power, 2017-01-03 19:22:01]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/v8/v8/+/199af0abb2bd2749673175e30389f937104...