[turbofan] Insert sigma nodes for loop variable backedge.

[turbofan] Insert sigma nodes for loop variable backedge.

If we infer loop variable bounds, we need to insert a type rename node
(sigma) to make sure that simplified lowering can choose representations
consistently.

Committed: https://crrev.com/e144335fe31e6700080103b468c6392fe49edcc3
Cr-Commit-Position: refs/heads/master@{#38391}

[Jarin, 2016-08-05 12:25:50]

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

[Jarin, 2016-08-05 12:25:50]

Could you take a look, please?

[Benedikt Meurer, 2016-08-05 12:45:06]

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

[commit-bot: I haz the power, 2016-08-05 12:45:10]

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, 2016-08-05 12:46:40]

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

[commit-bot: I haz the power, 2016-08-05 12:46:40]

Dry run: Try jobs failed on following builders:
  v8_linux64_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_rel_ng/builds/10426)
  v8_linux_mipsel_compile_rel on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_mipsel_compile_rel...)
  v8_linux_nodcheck_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_nodcheck_rel_ng/bu...)

[Benedikt Meurer, 2016-08-05 12:54:21]

LGTM modulo compile errors and nits.

https://codereview.chromium.org/2222513002/diff/1/src/compiler/common-operator.h
File src/compiler/common-operator.h (right):

https://codereview.chromium.org/2222513002/diff/1/src/compiler/common-operato...
src/compiler/common-operator.h:186: Type* SigmaTypeOf(Operator const*)
WARN_UNUSED_RESULT;
Nit: Rename to TypeOf

https://codereview.chromium.org/2222513002/diff/1/src/compiler/common-operato...
src/compiler/common-operator.h:253: const Operator* Sigma(Type* type);
Nit: Rename to TypeGuard

https://codereview.chromium.org/2222513002/diff/1/src/compiler/simplified-low...
File src/compiler/simplified-lowering.cc (right):

https://codereview.chromium.org/2222513002/diff/1/src/compiler/simplified-low...
src/compiler/simplified-lowering.cc:2466: ProcessInput(node, 1,
UseInfo::None());
Nit: You could use VisitUnop here.

[Jarin, 2016-08-05 13:00:58]

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

[commit-bot: I haz the power, 2016-08-05 13:01:07]

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, 2016-08-05 13:26:28]

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

[commit-bot: I haz the power, 2016-08-05 13:26:29]

Dry run: This issue passed the CQ dry run.

[Jarin, 2016-08-05 13:29:13]

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

[commit-bot: I haz the power, 2016-08-05 13:29:16]

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, 2016-08-05 13:52:43]

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

[commit-bot: I haz the power, 2016-08-05 13:52:44]

Dry run: This issue passed the CQ dry run.

[Jarin, 2016-08-05 14:05:08]

The CQ bit was checked by jarin@chromium.org

[Jarin, 2016-08-05 14:05:09]

The patchset sent to the CQ was uploaded after l-g-t-m from bmeurer@chromium.org
Link to the patchset: https://codereview.chromium.org/2222513002/#ps40001
(title: "Address comments")

[commit-bot: I haz the power, 2016-08-05 14:05:12]

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, 2016-08-05 14:32:09]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-08-05 14:34:19]

Description was changed from

==========
[turbofan] Insert sigma nodes for loop variable backedge.

If we infer loop variable bounds, we need to insert a type rename node
(sigma) to make sure that simplified lowering can choose representations
consistently.
==========

to

==========
[turbofan] Insert sigma nodes for loop variable backedge.

If we infer loop variable bounds, we need to insert a type rename node
(sigma) to make sure that simplified lowering can choose representations
consistently.

Committed: https://crrev.com/e144335fe31e6700080103b468c6392fe49edcc3
Cr-Commit-Position: refs/heads/master@{#38391}
==========

[commit-bot: I haz the power, 2016-08-05 14:34:20]

Patchset 3 (id:??) landed as
https://crrev.com/e144335fe31e6700080103b468c6392fe49edcc3
Cr-Commit-Position: refs/heads/master@{#38391}