[ignition] Use Smis directly for type feedback

[ignition] Use Smis directly for type feedback

Since type feedback is stored as Smis, we can avoid a few shift
instructions per bytecode handler by performing type feedback updates
on Smis directly, rather than converting between Smi and Word32.

Review-Url: https://codereview.chromium.org/2624753002
Cr-Commit-Position: refs/heads/master@{#42236}
Committed: https://chromium.googlesource.com/v8/v8/+/1f55c1b5aec2bcceba4b8d3a25bcf9cccce1a59b

[Leszek Swirski, 2017-01-10 13:54:35]

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

[commit-bot: I haz the power, 2017-01-10 13:54:47]

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, 2017-01-10 14:23:25]

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

[commit-bot: I haz the power, 2017-01-10 14:23:26]

Dry run: This issue passed the CQ dry run.

[Leszek Swirski, 2017-01-10 14:24:46]

leszeks@chromium.org changed reviewers:
+ mythria@chromium.org, rmcilroy@chromium.org

[Leszek Swirski, 2017-01-10 14:24:46]

Hi Ross and Mythri,

Here's a low impact (both in terms of code change and performance improvement)
patch to get rid of those pesky shifts in type feedback updates.

[rmcilroy, 2017-01-10 15:05:50]

LGTM with a suggestion.

https://codereview.chromium.org/2624753002/diff/1/src/code-stub-assembler.h
File src/code-stub-assembler.h (right):

https://codereview.chromium.org/2624753002/diff/1/src/code-stub-assembler.h#n...
src/code-stub-assembler.h:236: Node* SelectSmiConstant(Node* condition, Smi*
true_value, Smi* false_value);
nit - I would prefer just to have the Smi version of this function and always do
Smi::FromInt explicitly in the caller.

[mythria, 2017-01-10 15:49:14]

lgtm.

[Leszek Swirski, 2017-01-11 10:10:03]

https://codereview.chromium.org/2624753002/diff/1/src/code-stub-assembler.h
File src/code-stub-assembler.h (right):

https://codereview.chromium.org/2624753002/diff/1/src/code-stub-assembler.h#n...
src/code-stub-assembler.h:236: Node* SelectSmiConstant(Node* condition, Smi*
true_value, Smi* false_value);
On 2017/01/10 15:05:50, rmcilroy wrote:
> nit - I would prefer just to have the Smi version of this function and always
do
> Smi::FromInt explicitly in the caller.

I'd rather keep this as is, for consistency with SmiConstant, and since the
whole point is to be a convenience method (currently used in 9 places). I could
move the implementations to .cc though?

[rmcilroy, 2017-01-11 14:56:54]

On 2017/01/11 10:10:03, Leszek Swirski wrote:
> https://codereview.chromium.org/2624753002/diff/1/src/code-stub-assembler.h
> File src/code-stub-assembler.h (right):
> 
>
https://codereview.chromium.org/2624753002/diff/1/src/code-stub-assembler.h#n...
> src/code-stub-assembler.h:236: Node* SelectSmiConstant(Node* condition, Smi*
> true_value, Smi* false_value);
> On 2017/01/10 15:05:50, rmcilroy wrote:
> > nit - I would prefer just to have the Smi version of this function and
always
> do
> > Smi::FromInt explicitly in the caller.
> 
> I'd rather keep this as is, for consistency with SmiConstant, and since the
> whole point is to be a convenience method (currently used in 9 places). I
could
> move the implementations to .cc though?

Ok, I'm fine with this. Still LGTM.

[Leszek Swirski, 2017-01-11 14:57:46]

The CQ bit was checked by leszeks@chromium.org

[commit-bot: I haz the power, 2017-01-11 14:57:49]

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, 2017-01-11 15:28:15]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1484146666311790, "parent_rev":
"ec45e6ed2e11698c713e664b1510bc31bcdbbdba", "commit_rev":
"1f55c1b5aec2bcceba4b8d3a25bcf9cccce1a59b"}

[commit-bot: I haz the power, 2017-01-11 15:28:19]

Description was changed from

==========
[ignition] Use Smis directly for type feedback

Since type feedback is stored as Smis, we can avoid a few shift
instructions per bytecode handler by performing type feedback updates
on Smis directly, rather than converting between Smi and Word32.
==========

to

==========
[ignition] Use Smis directly for type feedback

Since type feedback is stored as Smis, we can avoid a few shift
instructions per bytecode handler by performing type feedback updates
on Smis directly, rather than converting between Smi and Word32.

Review-Url: https://codereview.chromium.org/2624753002
Cr-Commit-Position: refs/heads/master@{#42236}
Committed:
https://chromium.googlesource.com/v8/v8/+/1f55c1b5aec2bcceba4b8d3a25bcf9cccce...
==========

[commit-bot: I haz the power, 2017-01-11 15:28:20]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/v8/v8/+/1f55c1b5aec2bcceba4b8d3a25bcf9cccce...