[turbofan] Tentative fix for ControlEquivalence crasher.

[turbofan] Tentative fix for ControlEquivalence crasher.

The ControlEquivalence cannot deal with new nodes inserted by the
Scheduler due to Node splitting. Rather when the ControlEquivalence
sees such a new Node, it'll likely crash on an out-of-bounds access.

This is a speculative fix to make the crash disappear, as there's no
100% reliable repro currently.

BUG=chromium:629398
TBR=jochen@chromium.org

Review-Url: https://codereview.chromium.org/2611603002
Cr-Commit-Position: refs/heads/master@{#42016}
Committed: https://chromium.googlesource.com/v8/v8/+/64e5143dfe25ba80ad092f52f99460a825188c06

[Benedikt Meurer, 2017-01-03 05:27:08]

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

[commit-bot: I haz the power, 2017-01-03 05:27:11]

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

[Benedikt Meurer, 2017-01-03 05:27:17]

The CQ bit was unchecked by bmeurer@chromium.org

[Benedikt Meurer, 2017-01-03 05:27:21]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2017-01-03 05:27:31]

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 05:52:27]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1483421241323290, "parent_rev":
"589ecbfa85a7e1b3e80d85a6af2f3488009982bc", "commit_rev":
"64e5143dfe25ba80ad092f52f99460a825188c06"}

[commit-bot: I haz the power, 2017-01-03 05:52:32]

Description was changed from

==========
[turbofan] Tentative fix for ControlEquivalence crasher.

The ControlEquivalence cannot deal with new nodes inserted by the
Scheduler due to Node splitting. Rather when the ControlEquivalence
sees such a new Node, it'll likely crash on an out-of-bounds access.

This is a speculative fix to make the crash disappear, as there's no
100% reliable repro currently.

BUG=chromium:629398
TBR=jochen@chromium.org
==========

to

==========
[turbofan] Tentative fix for ControlEquivalence crasher.

The ControlEquivalence cannot deal with new nodes inserted by the
Scheduler due to Node splitting. Rather when the ControlEquivalence
sees such a new Node, it'll likely crash on an out-of-bounds access.

This is a speculative fix to make the crash disappear, as there's no
100% reliable repro currently.

BUG=chromium:629398
TBR=jochen@chromium.org

Review-Url: https://codereview.chromium.org/2611603002
Cr-Commit-Position: refs/heads/master@{#42016}
Committed:
https://chromium.googlesource.com/v8/v8/+/64e5143dfe25ba80ad092f52f99460a8251...
==========

[commit-bot: I haz the power, 2017-01-03 05:52:33]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/v8/v8/+/64e5143dfe25ba80ad092f52f99460a8251...

[jochen (gone - plz use gerrit), 2017-01-03 08:31:45]

while this will fix the crash, I'm not sure whether the resulting schedule is
still correct

A more heavy-handed approach would wipe the entire node_data_ vector in Run() if
the graph has changed in size.