[turbofan] Avoid -0 checks for truncating word32 uses.

[turbofan] Avoid -0 checks for truncating word32 uses.

The CheckBounds operator identifies zeros, but we ignore these bits in
the representation selector, which generates unnecessary -0 checks for
array accesses.

R=jarin@chromium.org
BUG=v8:5267
Review-Url: https://codereview.chromium.org/2823203002
Cr-Commit-Position: refs/heads/master@{#44680}
Committed: https://chromium.googlesource.com/v8/v8/+/bd72be6f43e010e59c28c71f2d571c63cf9282a3

[Benedikt Meurer, 2017-04-18 11:23:10]

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

[commit-bot: I haz the power, 2017-04-18 11:23:12]

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

[Jarin, 2017-04-18 11:24:50]

lgtm

[Benedikt Meurer, 2017-04-18 11:27:00]

The CQ bit was unchecked by bmeurer@chromium.org

[Benedikt Meurer, 2017-04-18 11:27:02]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2017-04-18 11:27:12]

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, 2017-04-18 11:48:04]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1492514822876420, "parent_rev":
"5d2c6ec33d826d6d6aed3697c676301e3f3f9d37", "commit_rev":
"bd72be6f43e010e59c28c71f2d571c63cf9282a3"}

[commit-bot: I haz the power, 2017-04-18 11:48:09]

Description was changed from

==========
[turbofan] Avoid -0 checks for truncating word32 uses.

The CheckBounds operator identifies zeros, but we ignore these bits in
the representation selector, which generates unnecessary -0 checks for
array accesses.

R=jarin@chromium.org
BUG=v8:5267
==========

to

==========
[turbofan] Avoid -0 checks for truncating word32 uses.

The CheckBounds operator identifies zeros, but we ignore these bits in
the representation selector, which generates unnecessary -0 checks for
array accesses.

R=jarin@chromium.org
BUG=v8:5267

Review-Url: https://codereview.chromium.org/2823203002
Cr-Commit-Position: refs/heads/master@{#44680}
Committed:
https://chromium.googlesource.com/v8/v8/+/bd72be6f43e010e59c28c71f2d571c63cf9...
==========

[commit-bot: I haz the power, 2017-04-18 11:48:10]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/v8/v8/+/bd72be6f43e010e59c28c71f2d571c63cf9...