[turbofan] Prevent storing signalling NaNs into holey double arrays.

[turbofan] Prevent storing signalling NaNs into holey double arrays.

This introduces SilenceNaN operator, which makes sure that we only
store quiet NaNs into holey arrays. We omit the NaN silencing code
at instruction selection time if the input is an operation that
cannot possibly produce signalling NaNs.

BUG=

Committed: https://crrev.com/6470ddadf93594657acee02b5ce5459752928490
Cr-Commit-Position: refs/heads/master@{#36950}

[Jarin, 2016-06-13 15:26:21]

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

[Jarin, 2016-06-13 15:26:22]

Could you take a look, please?

(I copied the mips implementation blindly from lithium, I guess I could clean it
up a bit.)

[Benedikt Meurer, 2016-06-13 17:26:30]

lgtm with nit

https://codereview.chromium.org/2060233002/diff/60001/src/compiler/instructio...
File src/compiler/instruction-selector.h (right):

https://codereview.chromium.org/2060233002/diff/60001/src/compiler/instructio...
src/compiler/instruction-selector.h:276: bool CanProduceSignallingNaN(Node*
node);
Nit: signaling

[Jarin, 2016-06-14 07:50:51]

The CQ bit was checked by jarin@chromium.org

[Jarin, 2016-06-14 07:50:52]

The patchset sent to the CQ was uploaded after l-g-t-m from bmeurer@chromium.org
Link to the patchset: https://codereview.chromium.org/2060233002/#ps80001
(title: "Fix spelling, rebase")

[commit-bot: I haz the power, 2016-06-14 07:51:01]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2060233002/80001

[commit-bot: I haz the power, 2016-06-14 08:23:22]

Committed patchset #5 (id:80001)

[commit-bot: I haz the power, 2016-06-14 08:23:23]

CQ bit was unchecked

[commit-bot: I haz the power, 2016-06-14 08:24:52]

Description was changed from

==========
[turbofan] Prevent storing signalling NaNs into holey double arrays.

This introduces SilenceNaN operator, which makes sure that we only
store quiet NaNs into holey arrays. We omit the NaN silencing code
at instruction selection time if the input is an operation that
cannot possibly produce signalling NaNs.

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

to

==========
[turbofan] Prevent storing signalling NaNs into holey double arrays.

This introduces SilenceNaN operator, which makes sure that we only
store quiet NaNs into holey arrays. We omit the NaN silencing code
at instruction selection time if the input is an operation that
cannot possibly produce signalling NaNs.

BUG=

Committed: https://crrev.com/6470ddadf93594657acee02b5ce5459752928490
Cr-Commit-Position: refs/heads/master@{#36950}
==========

[commit-bot: I haz the power, 2016-06-14 08:24:53]

Patchset 5 (id:??) landed as
https://crrev.com/6470ddadf93594657acee02b5ce5459752928490
Cr-Commit-Position: refs/heads/master@{#36950}