MIPS64: Implement the Word64Clz TurboFan operator.

MIPS64: Implement the Word64Clz TurboFan operator.

Port https://codereview.chromium.org/1413463009/

Includes adding dclz instruction.

BUG=

[paul.l..., 2015-11-06 06:29:15]

paul.lind@imgtec.com changed reviewers:
+ ahaas@chromium.org, akos.palfi@imgtec.com

[paul.l..., 2015-11-06 06:29:16]

Andreas, here is a mips64 CL to be merged into your
https://codereview.chromium.org/1413463009/

Since this is based on master, there will be a tiny merge conflict with the
mips64 instruction selector change in your CL. It's trivial to resolve.

[ahaas, 2015-11-10 09:24:51]

On 2015/11/06 at 06:29:16, paul.lind wrote:
> Andreas, here is a mips64 CL to be merged into your
https://codereview.chromium.org/1413463009/
> 
> Since this is based on master, there will be a tiny merge conflict with the
mips64 instruction selector change in your CL. It's trivial to resolve.

I included committed this CL in https://codereview.chromium.org/1413463009.