[turbofan] Replace shr of masked bits with zero

[turbofan] Replace shr of masked bits with zero

If (mask >>> s) == 0, ((x & mask) >> s) == 0, so replace the node with zero in
MachineOperatorReducer.

BUG=

Committed: https://crrev.com/d3597aee1f4caf1110ec1eb0047a2c421faacf12
Cr-Commit-Position: refs/heads/master@{#37046}

[martyn.capewell, 2016-06-15 10:00:35]

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

[Benedikt Meurer, 2016-06-17 04:21:45]

The CQ bit was checked by bmeurer@chromium.org

[Benedikt Meurer, 2016-06-17 04:21:45]

lgtm

[commit-bot: I haz the power, 2016-06-17 04:21:53]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2069973002/1

[commit-bot: I haz the power, 2016-06-17 04:48:41]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-06-17 04:49:42]

Description was changed from

==========
[turbofan] Replace shr of masked bits with zero

If (mask >>> s) == 0, ((x & mask) >> s) == 0, so replace the node with zero in
MachineOperatorReducer.

BUG=
==========

to

==========
[turbofan] Replace shr of masked bits with zero

If (mask >>> s) == 0, ((x & mask) >> s) == 0, so replace the node with zero in
MachineOperatorReducer.

BUG=

Committed: https://crrev.com/d3597aee1f4caf1110ec1eb0047a2c421faacf12
Cr-Commit-Position: refs/heads/master@{#37046}
==========

[commit-bot: I haz the power, 2016-06-17 04:49:43]

Patchset 1 (id:??) landed as
https://crrev.com/d3597aee1f4caf1110ec1eb0047a2c421faacf12
Cr-Commit-Position: refs/heads/master@{#37046}