[turbofan] Elide no-op adds in x64 index addressing modes

[turbofan] Elide no-op adds in x64 index addressing modes

Before this patch, Loads generated in the CSA on x64 that have a zero offset
displacement will add a zero to the effective address rather than using an
addressing mode that folds away the zero.

This functionality already exists on ia32, but the port wasn't purely mechanical
so it hadn't been done on x64.

R=epertoso@chromium.org
LOG=N

Review-Url: https://codereview.chromium.org/2602893002
Cr-Commit-Position: refs/heads/master@{#41974}
Committed: https://chromium.googlesource.com/v8/v8/+/1d96354714bda107bfef69fbbc1f0ee8f91fe6df

[danno, 2016-12-28 15:48:04]

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

[commit-bot: I haz the power, 2016-12-28 15:48:07]

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

[danno, 2016-12-28 15:49:05]

ptal

[epertoso, 2016-12-28 15:52:31]

lgtm

[commit-bot: I haz the power, 2016-12-28 16:10:44]

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

[commit-bot: I haz the power, 2016-12-28 16:10:45]

Dry run: This issue passed the CQ dry run.

[danno, 2016-12-28 16:11:45]

The CQ bit was checked by danno@chromium.org

[commit-bot: I haz the power, 2016-12-28 16:11:55]

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, 2016-12-28 16:13:32]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1482941505626330, "parent_rev":
"d083833499e2be9518d226d75ee6183ad3adc67b", "commit_rev":
"1d96354714bda107bfef69fbbc1f0ee8f91fe6df"}

[commit-bot: I haz the power, 2016-12-28 16:13:38]

Description was changed from

==========
[turbofan] Elide no-op adds in x64 index addressing modes

Before this patch, Loads generated in the CSA on x64 that have a zero offset
displacement will add a zero to the effective address rather than using an
addressing mode that folds away the zero.

This functionality already exists on ia32, but the port wasn't purely mechanical
so it hadn't been done on x64.

R=epertoso@chromium.org
LOG=N
==========

to

==========
[turbofan] Elide no-op adds in x64 index addressing modes

Before this patch, Loads generated in the CSA on x64 that have a zero offset
displacement will add a zero to the effective address rather than using an
addressing mode that folds away the zero.

This functionality already exists on ia32, but the port wasn't purely mechanical
so it hadn't been done on x64.

R=epertoso@chromium.org
LOG=N

Review-Url: https://codereview.chromium.org/2602893002
Cr-Commit-Position: refs/heads/master@{#41974}
Committed:
https://chromium.googlesource.com/v8/v8/+/1d96354714bda107bfef69fbbc1f0ee8f91...
==========

[commit-bot: I haz the power, 2016-12-28 16:13:39]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/v8/v8/+/1d96354714bda107bfef69fbbc1f0ee8f91...