[ARM] Implement widening and narrowing integer moves, vmovl, vqmovn.

[ARM] Implement widening and narrowing integer moves, vmovl, vqmovn.
- Fixes vmovl for widening 16 to 32, 32 to 64.
- Adds vqmovn.

LOG=N
BUG=v8:6020
Review-Url: https://codereview.chromium.org/2773303002
Cr-Commit-Position: refs/heads/master@{#44156}
Committed: https://chromium.googlesource.com/v8/v8/+/d7a09280d700b9bb44a0f4adba24577294f52885

[bbudge, 2017-03-25 21:12:27]

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

[commit-bot: I haz the power, 2017-03-25 21:12:30]

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, 2017-03-25 21:33:37]

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

[commit-bot: I haz the power, 2017-03-25 21:33:38]

Dry run: This issue passed the CQ dry run.

[bbudge, 2017-03-26 00:30:15]

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

[commit-bot: I haz the power, 2017-03-26 00:30:24]

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, 2017-03-26 00:51:55]

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

[commit-bot: I haz the power, 2017-03-26 00:51:56]

Dry run: This issue passed the CQ dry run.

[bbudge, 2017-03-26 23:03:39]

bbudge@chromium.org changed reviewers:
+ bmeurer@chromium.org, martyn.capewell@arm.com

[bbudge, 2017-03-26 23:08:51]

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

[commit-bot: I haz the power, 2017-03-26 23:09:01]

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, 2017-03-26 23:29:31]

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

[commit-bot: I haz the power, 2017-03-26 23:29:32]

Dry run: This issue passed the CQ dry run.

[Benedikt Meurer, 2017-03-27 03:23:32]

lgtm

[martyn.capewell, 2017-03-27 13:19:43]

https://codereview.chromium.org/2773303002/diff/40001/src/arm/simulator-arm.cc
File src/arm/simulator-arm.cc (right):

https://codereview.chromium.org/2773303002/diff/40001/src/arm/simulator-arm.c...
src/arm/simulator-arm.cc:4010: return static_cast<U>(value);
This is potentially unsafe for signed types if the value can't be represented in
the destination type, though it's fine at the moment, as the inputs are always
clamped.

Perhaps assert the signedness is compatible, too?

https://codereview.chromium.org/2773303002/diff/40001/src/arm/simulator-arm.c...
src/arm/simulator-arm.cc:4040: void Narrow(Simulator* simulator, int Vd, int Vm)
{
This may be better named SaturatingNarrow(). If you later need to implement
vmovn, you'll need a non-saturating version of this function, or an extra
parameter to this one.

https://codereview.chromium.org/2773303002/diff/40001/test/cctest/test-disasm...
File test/cctest/test-disasm-arm.cc (right):

https://codereview.chromium.org/2773303002/diff/40001/test/cctest/test-disasm...
test/cctest/test-disasm-arm.cc:941: COMPARE(vqmovn(NeonU8, d16, q8), "f3f202e0  
    vqmovn.u16 d16, q8");
It seems confusing that vqmovn(NeonU8...) disassembles to vqmovn.u16. I notice
the comment in the assembler header file, so I guess it's consistent.

[bbudge, 2017-03-27 17:42:14]

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

[commit-bot: I haz the power, 2017-03-27 17:42:23]

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

[bbudge, 2017-03-27 17:47:24]

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

[commit-bot: I haz the power, 2017-03-27 17:47:33]

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

[bbudge, 2017-03-27 17:48:02]

https://codereview.chromium.org/2773303002/diff/40001/src/arm/simulator-arm.cc
File src/arm/simulator-arm.cc (right):

https://codereview.chromium.org/2773303002/diff/40001/src/arm/simulator-arm.c...
src/arm/simulator-arm.cc:4010: return static_cast<U>(value);
On 2017/03/27 13:19:43, martyn.capewell wrote:
> This is potentially unsafe for signed types if the value can't be represented
in
> the destination type, though it's fine at the moment, as the inputs are always
> clamped.
> 
> Perhaps assert the signedness is compatible, too?

Done. Also added checks that value can be expressed in the narrower type.

https://codereview.chromium.org/2773303002/diff/40001/src/arm/simulator-arm.c...
src/arm/simulator-arm.cc:4040: void Narrow(Simulator* simulator, int Vd, int Vm)
{
On 2017/03/27 13:19:43, martyn.capewell wrote:
> This may be better named SaturatingNarrow(). If you later need to implement
> vmovn, you'll need a non-saturating version of this function, or an extra
> parameter to this one.

Done.

https://codereview.chromium.org/2773303002/diff/40001/test/cctest/test-disasm...
File test/cctest/test-disasm-arm.cc (right):

https://codereview.chromium.org/2773303002/diff/40001/test/cctest/test-disasm...
test/cctest/test-disasm-arm.cc:941: COMPARE(vqmovn(NeonU8, d16, q8), "f3f202e0  
    vqmovn.u16 d16, q8");
On 2017/03/27 13:19:43, martyn.capewell wrote:
> It seems confusing that vqmovn(NeonU8...) disassembles to vqmovn.u16. I notice
> the comment in the assembler header file, so I guess it's consistent.

Otherwise, I'd need to extend the NeonDataType enum, which seems like it might
be disruptive.

[commit-bot: I haz the power, 2017-03-27 18:09:13]

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

[commit-bot: I haz the power, 2017-03-27 18:09:14]

Dry run: This issue passed the CQ dry run.

[martyn.capewell, 2017-03-27 18:13:30]

lgtm

[bbudge, 2017-03-27 18:22:19]

The CQ bit was checked by bbudge@chromium.org

[bbudge, 2017-03-27 18:22:19]

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/2773303002/#ps80001
(title: "Missed file.")

[commit-bot: I haz the power, 2017-03-27 18:22:24]

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, 2017-03-27 18:23:43]

CQ is committing da patch.

Bot data: {"patchset_id": 80001, "attempt_start_ts": 1490638939246940,
"parent_rev": "bd8447af50e276c4e49e6aa4d06cd2bf2fc3522d", "commit_rev":
"d7a09280d700b9bb44a0f4adba24577294f52885"}

[commit-bot: I haz the power, 2017-03-27 18:23:49]

Description was changed from

==========
[ARM] Implement widening and narrowing integer moves, vmovl, vqmovn.
- Fixes vmovl for widening 16 to 32, 32 to 64.
- Adds vqmovn.

LOG=N
BUG=v8:6020
==========

to

==========
[ARM] Implement widening and narrowing integer moves, vmovl, vqmovn.
- Fixes vmovl for widening 16 to 32, 32 to 64.
- Adds vqmovn.

LOG=N
BUG=v8:6020

Review-Url: https://codereview.chromium.org/2773303002
Cr-Commit-Position: refs/heads/master@{#44156}
Committed:
https://chromium.googlesource.com/v8/v8/+/d7a09280d700b9bb44a0f4adba24577294f...
==========

[commit-bot: I haz the power, 2017-03-27 18:23:50]

Committed patchset #5 (id:80001) as
https://chromium.googlesource.com/v8/v8/+/d7a09280d700b9bb44a0f4adba24577294f...