[turbofan] Use bounds checks to eliminate subsequent inc/dec overflow checks.

[turbofan] Use bounds checks to eliminate subsequent inc/dec overflow checks.

This has two parts:
- in redundancy elimination, if we see addition with left hand side that
  was bounds-checked, we reconnect the lhs to the bounds check if it has better
  type.
- in representation inference, eliminate overflow checks if the input types
  guarantee no overflow.

Committed: https://crrev.com/cd0c259260d1b314e9983972114612f34f37274b
Cr-Commit-Position: refs/heads/master@{#41260}

[Jarin, 2016-11-24 10:06:50]

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

[commit-bot: I haz the power, 2016-11-24 10:06:59]

Dry run: 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, 2016-11-24 10:12:28]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-24 10:12:28]

Dry run: Try jobs failed on following builders:
  v8_linux64_gyp_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_gyp_rel_ng/build...)

[Jarin, 2016-11-24 10:26:25]

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

[commit-bot: I haz the power, 2016-11-24 10:26:27]

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

[Jarin, 2016-11-24 10:29:08]

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

[commit-bot: I haz the power, 2016-11-24 10:29:16]

Dry run: 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, 2016-11-24 10:52:51]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-24 10:52:52]

Dry run: This issue passed the CQ dry run.

[Jarin, 2016-11-24 10:56:58]

jarin@chromium.org changed reviewers:
+ bmeurer@chromium.org

[Jarin, 2016-11-24 10:56:59]

Could you take a look, please? 

This helps Octane/crypto a bit by eliminating couple of overflow checks from the
hot loop.

[Benedikt Meurer, 2016-11-24 12:30:46]

As per offline discussion, I'd do this for both inputs, and maybe apply the
simplified lowering magic to multiply as well.

[Benedikt Meurer, 2016-11-24 12:30:53]

Otherwise LGTM.

[Jarin, 2016-11-24 12:56:24]

The CQ bit was checked by jarin@chromium.org

[commit-bot: I haz the power, 2016-11-24 12:56:32]

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, 2016-11-24 12:58:03]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1479992184128540,
"parent_rev": "7c03250ca3ca25c9b3d65324083a08344ec1a78b", "commit_rev":
"c7ab77fb9ac47dd6ea87b21aaa7d7b11155d243d"}

[commit-bot: I haz the power, 2016-11-24 12:58:08]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-11-24 12:58:29]

Description was changed from

==========
[turbofan] Use bounds checks to eliminate subsequent inc/dec overflow checks.

This has two parts:
- in redundancy elimination, if we see addition with left hand side that
  was bounds-checked, we reconnect the lhs to the bounds check if it has better
  type.
- in representation inference, eliminate overflow checks if the input types
  guarantee no overflow.
==========

to

==========
[turbofan] Use bounds checks to eliminate subsequent inc/dec overflow checks.

This has two parts:
- in redundancy elimination, if we see addition with left hand side that
  was bounds-checked, we reconnect the lhs to the bounds check if it has better
  type.
- in representation inference, eliminate overflow checks if the input types
  guarantee no overflow.

Committed: https://crrev.com/cd0c259260d1b314e9983972114612f34f37274b
Cr-Commit-Position: refs/heads/master@{#41260}
==========

[commit-bot: I haz the power, 2016-11-24 12:58:30]

Patchset 2 (id:??) landed as
https://crrev.com/cd0c259260d1b314e9983972114612f34f37274b
Cr-Commit-Position: refs/heads/master@{#41260}