[turbofan] Revert invalid optimization of flooring division.

[turbofan] Revert invalid optimization of flooring division.

The optimization

  NumberFloor(NumberDivide(lhs, rhs))

to

  NumberToInt32(NumberDivide(lhs, rhs))

for potentially negative lhs is not valid, since Math.floor rounds
towards -infinity, whereas ToInt32 truncates.

BUG=chromium:699282
R=jarin@chromium.org

Review-Url: https://codereview.chromium.org/2743673002
Cr-Commit-Position: refs/heads/master@{#43699}
Committed: https://chromium.googlesource.com/v8/v8/+/18be5d7057d794dbe3b663dfc17d3e512f2b55e3

[Benedikt Meurer, 2017-03-09 12:22:34]

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

[commit-bot: I haz the power, 2017-03-09 12:22:39]

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

[Jarin, 2017-03-09 12:24:28]

lgtm

[Benedikt Meurer, 2017-03-09 12:24:38]

The CQ bit was unchecked by bmeurer@chromium.org

[Benedikt Meurer, 2017-03-09 12:24:42]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2017-03-09 12:24:49]

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

[Michael Achenbach, 2017-03-09 12:55:24]

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

[Michael Achenbach, 2017-03-09 12:55:24]

Is this important enough to require a merge for tomorrow's canary?

[Benedikt Meurer, 2017-03-09 12:57:45]

No, just correctness fix.

[commit-bot: I haz the power, 2017-03-09 13:41:39]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1489062282255450, "parent_rev":
"0ca72de24cc2b697bf8af91d5c3901495bf962d8", "commit_rev":
"18be5d7057d794dbe3b663dfc17d3e512f2b55e3"}

[commit-bot: I haz the power, 2017-03-09 13:41:43]

Description was changed from

==========
[turbofan] Revert invalid optimization of flooring division.

The optimization

  NumberFloor(NumberDivide(lhs, rhs))

to

  NumberToInt32(NumberDivide(lhs, rhs))

for potentially negative lhs is not valid, since Math.floor rounds
towards -infinity, whereas ToInt32 truncates.

BUG=chromium:699282
R=jarin@chromium.org
==========

to

==========
[turbofan] Revert invalid optimization of flooring division.

The optimization

  NumberFloor(NumberDivide(lhs, rhs))

to

  NumberToInt32(NumberDivide(lhs, rhs))

for potentially negative lhs is not valid, since Math.floor rounds
towards -infinity, whereas ToInt32 truncates.

BUG=chromium:699282
R=jarin@chromium.org

Review-Url: https://codereview.chromium.org/2743673002
Cr-Commit-Position: refs/heads/master@{#43699}
Committed:
https://chromium.googlesource.com/v8/v8/+/18be5d7057d794dbe3b663dfc17d3e512f2...
==========

[commit-bot: I haz the power, 2017-03-09 13:41:44]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/v8/v8/+/18be5d7057d794dbe3b663dfc17d3e512f2...