[turbofan] Distinguish between change- and truncate-tagged-to-float64.

[turbofan] Distinguish between change- and truncate-tagged-to-float64.

This prevents the compiler from optimizing
  f64-to-tagged(tagged-to-f64(x)) ==> x
for non-number x (such as undefined).

Committed: https://crrev.com/5e96f47bc895f3cba7179d6e4a6ab27488c5a576
Cr-Commit-Position: refs/heads/master@{#36613}

[Jarin, 2016-05-31 11:14:20]

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

[Jarin, 2016-05-31 11:14:21]

Could you take a look, please?

[Benedikt Meurer, 2016-05-31 11:27:49]

lgtm

[Jarin, 2016-05-31 11:28:33]

The CQ bit was checked by jarin@chromium.org

[commit-bot: I haz the power, 2016-05-31 11:28:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2027593002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/2027593002/1

[commit-bot: I haz the power, 2016-05-31 12:00:04]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-05-31 12:01:45]

Description was changed from

==========
[turbofan] Distinguish between change- and truncate-tagged-to-float64.

This prevents the compiler from optimizing
  f64-to-tagged(tagged-to-f64(x)) ==> x
for non-number x (such as undefined).
==========

to

==========
[turbofan] Distinguish between change- and truncate-tagged-to-float64.

This prevents the compiler from optimizing
  f64-to-tagged(tagged-to-f64(x)) ==> x
for non-number x (such as undefined).

Committed: https://crrev.com/5e96f47bc895f3cba7179d6e4a6ab27488c5a576
Cr-Commit-Position: refs/heads/master@{#36613}
==========

[commit-bot: I haz the power, 2016-05-31 12:01:46]

Patchset 1 (id:??) landed as
https://crrev.com/5e96f47bc895f3cba7179d6e4a6ab27488c5a576
Cr-Commit-Position: refs/heads/master@{#36613}