MIPS: Emit madd.d for multiply-add on MIPS.

MIPS: Emit madd.d for multiply-add on MIPS.

Based on commit r12958 (04586adf).

BUG=
TEST=

Committed: https://code.google.com/p/v8/source/detail?r=13342

[danno, 2013-01-09 07:50:52]

Yang, could you please take over the review of this CL and land it for Akos?

[Yang, 2013-01-09 12:31:06]

On 2013/01/09 07:50:52, danno wrote:
> Yang, could you please take over the review of this CL and land it for Akos?

LGTM. Landing.

Remark for the future not really related to this CL: both multiply-add and
floor-of-div essentially do the same thing. The former is implemented in
Lithium, the latter in Hydrogen. Both have their merits, but maybe we should
consistently consider choosing one over the other.

[hans, 2013-01-09 15:13:08]

On 2013/01/09 12:31:06, Yang wrote:
> Remark for the future not really related to this CL: both multiply-add and
> floor-of-div essentially do the same thing. The former is implemented in
> Lithium, the latter in Hydrogen. Both have their merits, but maybe we should
> consistently consider choosing one over the other.

For reference, here is the comment where Jakob suggested I'd do multiply-add
during Lithium formation: https://chromiumcodereview.appspot.com/11293061/#msg5

If we want to be consistent here, I could look into switching over the
floor-of-div code as a clean-up.

[Yang, 2013-01-09 15:15:35]

On 2013/01/09 15:13:08, hans wrote:
> On 2013/01/09 12:31:06, Yang wrote:
> > Remark for the future not really related to this CL: both multiply-add and
> > floor-of-div essentially do the same thing. The former is implemented in
> > Lithium, the latter in Hydrogen. Both have their merits, but maybe we should
> > consistently consider choosing one over the other.
> 
> For reference, here is the comment where Jakob suggested I'd do multiply-add
> during Lithium formation:
https://chromiumcodereview.appspot.com/11293061/#msg5
> 
> If we want to be consistent here, I could look into switching over the
> floor-of-div code as a clean-up.

That would be a good solution. Then again, I think we can consider that with low
priority.