[turbofan][x64] Use the root register for comparisons with certain roots.

[turbofan][x64] Use the root register for comparisons with certain roots.

Emit code like this

  cmpq reg, [kRootRegister + offset]

when selecting instructions for comparisons with immortal, immovable
roots. This reduces register pressure as we don't need to load those
roots into registers first.

R=jarin@chromium.org
TBR=hpayer@chromium.org

Committed: https://crrev.com/e17ea8ddf2b1d4e45d8d010638684850460b2e47
Cr-Commit-Position: refs/heads/master@{#40022}

[Benedikt Meurer, 2016-10-06 06:50:42]

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

[commit-bot: I haz the power, 2016-10-06 06:50:49]

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

[Benedikt Meurer, 2016-10-06 06:51:32]

Hey Jaro, Hannes,

This gives a small boost in some cases, and in general reduces register pressure
somewhat.
Please take a look.

Thanks,
Benedikt

[Jarin, 2016-10-06 07:14:57]

lgtm

[commit-bot: I haz the power, 2016-10-06 07:16:46]

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

[commit-bot: I haz the power, 2016-10-06 07:16:47]

Dry run: This issue passed the CQ dry run.

[Benedikt Meurer, 2016-10-06 08:16:33]

Description was changed from

==========
[turbofan][x64] Use the root register for comparisons with certain roots.

Emit code like this

  cmpq reg, [kRootRegister + offset]

when selecting instructions for comparisons with immortal, immovable
roots. This reduces register pressure as we don't need to load those
roots into registers first.

R=jarin@chromium.org,hpayer@chromium.org
==========

to

==========
[turbofan][x64] Use the root register for comparisons with certain roots.

Emit code like this

  cmpq reg, [kRootRegister + offset]

when selecting instructions for comparisons with immortal, immovable
roots. This reduces register pressure as we don't need to load those
roots into registers first.

R=jarin@chromium.org
TBR=hpayer@chromium.org
==========

[Benedikt Meurer, 2016-10-06 08:16:38]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2016-10-06 08:16:41]

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, 2016-10-06 08:19:04]

Description was changed from

==========
[turbofan][x64] Use the root register for comparisons with certain roots.

Emit code like this

  cmpq reg, [kRootRegister + offset]

when selecting instructions for comparisons with immortal, immovable
roots. This reduces register pressure as we don't need to load those
roots into registers first.

R=jarin@chromium.org
TBR=hpayer@chromium.org
==========

to

==========
[turbofan][x64] Use the root register for comparisons with certain roots.

Emit code like this

  cmpq reg, [kRootRegister + offset]

when selecting instructions for comparisons with immortal, immovable
roots. This reduces register pressure as we don't need to load those
roots into registers first.

R=jarin@chromium.org
TBR=hpayer@chromium.org
==========

[commit-bot: I haz the power, 2016-10-06 08:19:05]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-10-06 08:19:22]

Description was changed from

==========
[turbofan][x64] Use the root register for comparisons with certain roots.

Emit code like this

  cmpq reg, [kRootRegister + offset]

when selecting instructions for comparisons with immortal, immovable
roots. This reduces register pressure as we don't need to load those
roots into registers first.

R=jarin@chromium.org
TBR=hpayer@chromium.org
==========

to

==========
[turbofan][x64] Use the root register for comparisons with certain roots.

Emit code like this

  cmpq reg, [kRootRegister + offset]

when selecting instructions for comparisons with immortal, immovable
roots. This reduces register pressure as we don't need to load those
roots into registers first.

R=jarin@chromium.org
TBR=hpayer@chromium.org

Committed: https://crrev.com/e17ea8ddf2b1d4e45d8d010638684850460b2e47
Cr-Commit-Position: refs/heads/master@{#40022}
==========

[commit-bot: I haz the power, 2016-10-06 08:19:22]

Patchset 1 (id:??) landed as
https://crrev.com/e17ea8ddf2b1d4e45d8d010638684850460b2e47
Cr-Commit-Position: refs/heads/master@{#40022}