[wasm] Int64Lowering of Int64Mul on ia32 and arm.

[wasm] Int64Lowering of Int64Mul on ia32 and arm.

Int64Mul is lowered to a new turbofan operator, Int32MulPair. The new
operator takes 4 inputs an generates 2 outputs. The inputs are the low
word of the left input, high word of the left input, the low word of the
right input, and high word of the right input. The ouputs are the low
and high word of the result of the multiplication.

R=titzer@chromium.org, v8-arm-ports@googlegroups.com

Committed: https://crrev.com/40bdbef975779e41a7e81d3748342dd7da52977f
Cr-Commit-Position: refs/heads/master@{#35131}

[martyn.capewell, 2016-03-17 18:20:29]

martyn.capewell@arm.com changed reviewers:
+ martyn.capewell@arm.com

[martyn.capewell, 2016-03-17 18:20:29]

https://codereview.chromium.org/1807273002/diff/20001/src/compiler/arm/code-g...
File src/compiler/arm/code-generator-arm.cc (right):

https://codereview.chromium.org/1807273002/diff/20001/src/compiler/arm/code-g...
src/compiler/arm/code-generator-arm.cc:822: __ add(i.OutputRegister(1),
i.OutputRegister(1), i.TempRegister(0));
I think if you use multiply-accumulates here, you won't need temp registers:
  __ mul(i.OutputRegister(1), i.InputRegister(0), i.InputRegister(3));
  __ mla(i.OutputRegister(1), i.InputRegister(2), i.InputRegister(1),
i.OutputRegister(1));
  __ mov(i.OutputRegister(0), Operand(0));
  __ umlal(i.OutputRegister(0), i.OutputRegister(1), i.InputRegister(0),
i.InputRegister(2));

[martyn.capewell, 2016-03-18 11:42:49]

https://codereview.chromium.org/1807273002/diff/20001/src/compiler/arm/code-g...
File src/compiler/arm/code-generator-arm.cc (right):

https://codereview.chromium.org/1807273002/diff/20001/src/compiler/arm/code-g...
src/compiler/arm/code-generator-arm.cc:822: __ add(i.OutputRegister(1),
i.OutputRegister(1), i.TempRegister(0));
A bit more thought gives:
  __ umull(i.OutputRegister(0), i.OutputRegister(1), i.InputRegister(0),
i.InputRegister(2));
  __ mla(i.OutputRegister(1), i.InputRegister(0), i.InputRegister(3),
i.OutputRegister(1));
  __ mla(i.OutputRegister(1), i.InputRegister(2), i.InputRegister(1),
i.OutputRegister(1));

[titzer, 2016-03-29 09:43:19]

lgtm

[ahaas, 2016-03-29 11:11:50]

https://codereview.chromium.org/1807273002/diff/20001/src/compiler/arm/code-g...
File src/compiler/arm/code-generator-arm.cc (right):

https://codereview.chromium.org/1807273002/diff/20001/src/compiler/arm/code-g...
src/compiler/arm/code-generator-arm.cc:822: __ add(i.OutputRegister(1),
i.OutputRegister(1), i.TempRegister(0));
On 2016/03/18 at 11:42:49, martyn.capewell wrote:
> A bit more thought gives:
>   __ umull(i.OutputRegister(0), i.OutputRegister(1), i.InputRegister(0),
i.InputRegister(2));
>   __ mla(i.OutputRegister(1), i.InputRegister(0), i.InputRegister(3),
i.OutputRegister(1));
>   __ mla(i.OutputRegister(1), i.InputRegister(2), i.InputRegister(1),
i.OutputRegister(1));

Done. It was necessary for this change to use a unique register for input 3.

[martyn.capewell, 2016-03-29 17:56:51]

Cool. ARM parts lgtm.

[ahaas, 2016-03-30 10:37:16]

The CQ bit was checked by ahaas@chromium.org

[ahaas, 2016-03-30 10:37:16]

The patchset sent to the CQ was uploaded after l-g-t-m from titzer@chromium.org,
martyn.capewell@arm.com
Link to the patchset: https://codereview.chromium.org/1807273002/#ps60001
(title: "Rebase")

[commit-bot: I haz the power, 2016-03-30 10:37:25]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1807273002/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1807273002/60001

[commit-bot: I haz the power, 2016-03-30 10:39:16]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2016-03-30 10:40:16]

Description was changed from

==========
[wasm] Int64Lowering of Int64Mul on ia32 and arm.

Int64Mul is lowered to a new turbofan operator, Int32MulPair. The new
operator takes 4 inputs an generates 2 outputs. The inputs are the low
word of the left input, high word of the left input, the low word of the
right input, and high word of the right input. The ouputs are the low
and high word of the result of the multiplication.

R=titzer@chromium.org, v8-arm-ports@googlegroups.com
==========

to

==========
[wasm] Int64Lowering of Int64Mul on ia32 and arm.

Int64Mul is lowered to a new turbofan operator, Int32MulPair. The new
operator takes 4 inputs an generates 2 outputs. The inputs are the low
word of the left input, high word of the left input, the low word of the
right input, and high word of the right input. The ouputs are the low
and high word of the result of the multiplication.

R=titzer@chromium.org, v8-arm-ports@googlegroups.com

Committed: https://crrev.com/40bdbef975779e41a7e81d3748342dd7da52977f
Cr-Commit-Position: refs/heads/master@{#35131}
==========

[commit-bot: I haz the power, 2016-03-30 10:40:19]

Patchset 4 (id:??) landed as
https://crrev.com/40bdbef975779e41a7e81d3748342dd7da52977f
Cr-Commit-Position: refs/heads/master@{#35131}