[turbofan] Try harder to avoid write barriers when writing Smis.

[turbofan] Try harder to avoid write barriers when writing Smis.

This avoids write barrier when writing smis to tagged fields.

This includes writing to contexts, see example below:

var f = (function() {
  var i = 0;
  return function f() {
    return i++;  // Write barrier when writing to context.
  }
})();

f(); f(); %OptimizeFunctionOnNextCall(f);
f();

Review-Url: https://codereview.chromium.org/2925793002
Cr-Commit-Position: refs/heads/master@{#45723}
Committed: https://chromium.googlesource.com/v8/v8/+/c22ca7f73ba92f22d0cd29b06bb2944a545a8d3e

[Jarin, 2017-06-06 09:55:08]

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

[commit-bot: I haz the power, 2017-06-06 09:55:17]

Dry run: CQ is trying da patch.

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

[Jarin, 2017-06-06 09:55:56]

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

[Jarin, 2017-06-06 09:55:57]

Could you take a look, please?

[commit-bot: I haz the power, 2017-06-06 10:23:41]

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

[commit-bot: I haz the power, 2017-06-06 10:23:42]

Dry run: This issue passed the CQ dry run.

[Benedikt Meurer, 2017-06-06 10:32:47]

LGTM modulo nit.

https://codereview.chromium.org/2925793002/diff/1/src/compiler/simplified-low...
File src/compiler/simplified-lowering.cc (right):

https://codereview.chromium.org/2925793002/diff/1/src/compiler/simplified-low...
src/compiler/simplified-lowering.cc:2486: access.type,
input_info->representation(), node->InputAt(1));
Please give the node->InputAt(1) a name. (Same below)

[Jarin, 2017-06-06 10:37:00]

The CQ bit was checked by jarin@chromium.org

[Jarin, 2017-06-06 10:37:00]

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/2925793002/#ps20001
(title: "Address reviewer comments")

[commit-bot: I haz the power, 2017-06-06 10:37:10]

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, 2017-06-06 11:05:20]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1496745420217770,
"parent_rev": "0897efb86b3c5a512d65fb428598609ef1e77d08", "commit_rev":
"c22ca7f73ba92f22d0cd29b06bb2944a545a8d3e"}

[commit-bot: I haz the power, 2017-06-06 11:05:28]

Description was changed from

==========
[turbofan] Try harder to avoid write barriers when writing Smis.

This avoids write barrier when writing smis to tagged fields.

This includes writing to contexts, see example below:

var f = (function() {
  var i = 0;
  return function f() {
    return i++;  // Write barrier when writing to context.
  }
})();

f(); f(); %OptimizeFunctionOnNextCall(f);
f();
==========

to

==========
[turbofan] Try harder to avoid write barriers when writing Smis.

This avoids write barrier when writing smis to tagged fields.

This includes writing to contexts, see example below:

var f = (function() {
  var i = 0;
  return function f() {
    return i++;  // Write barrier when writing to context.
  }
})();

f(); f(); %OptimizeFunctionOnNextCall(f);
f();

Review-Url: https://codereview.chromium.org/2925793002
Cr-Commit-Position: refs/heads/master@{#45723}
Committed:
https://chromium.googlesource.com/v8/v8/+/c22ca7f73ba92f22d0cd29b06bb2944a545...
==========

[commit-bot: I haz the power, 2017-06-06 11:05:29]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/v8/v8/+/c22ca7f73ba92f22d0cd29b06bb2944a545...