[turbofan] Reenable value numbering.

[turbofan] Reenable value numbering.

Value numbering is now limited to eliminatable operators (i.e. operators
that don't throw and don't write), and uses linear probing instead of
separate chaining.

TEST=unittests
R=svenpanne@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=24452

[Benedikt Meurer, 2014-10-08 07:34:35]

bmeurer@chromium.org changed reviewers:
- mstarzinger@chromium.org

[Benedikt Meurer, 2014-10-08 07:37:34]

bmeurer@chromium.org changed reviewers:
+ svenpanne@chromium.org

[Benedikt Meurer, 2014-10-08 07:37:34]

bmeurer@chromium.org changed reviewers:
+ svenpanne@chromium.org

[Benedikt Meurer, 2014-10-08 07:37:35]

PTAL

[Benedikt Meurer, 2014-10-08 07:37:35]

PTAL

[Sven Panne, 2014-10-08 07:51:33]

lgtm

[Michael Starzinger, 2014-10-08 07:53:01]

mstarzinger@chromium.org changed reviewers:
+ mstarzinger@chromium.org

[Michael Starzinger, 2014-10-08 07:53:02]

https://codereview.chromium.org/630423002/diff/1/src/compiler/pipeline.cc
File src/compiler/pipeline.cc (right):

https://codereview.chromium.org/630423002/diff/1/src/compiler/pipeline.cc#new...
src/compiler/pipeline.cc:293: // TODO(turbofan): Value numbering disabled for
now.
The TODO can be dropped.

[Benedikt Meurer, 2014-10-08 08:05:28]

https://codereview.chromium.org/630423002/diff/1/src/compiler/pipeline.cc
File src/compiler/pipeline.cc (right):

https://codereview.chromium.org/630423002/diff/1/src/compiler/pipeline.cc#new...
src/compiler/pipeline.cc:293: // TODO(turbofan): Value numbering disabled for
now.
On 2014/10/08 07:53:02, Michael Starzinger wrote:
> The TODO can be dropped.

Done.

[Benedikt Meurer, 2014-10-08 08:07:18]

Committed patchset #3 (id:40001) manually as 24452 (presubmit successful).