[turbofan] Only infer signedness for Float64->Word32 representation change from the input type.

[turbofan] Only infer signedness for Float64->Word32 representation change from the input type.

If the input type does not help us, we are conservative and truncate (rather than guessing signed).

Committed: https://crrev.com/a9fa0498e1cc4e53f63ef0f927b86793a4bd4cc6
Cr-Commit-Position: refs/heads/master@{#32075}

[Jarin, 2015-11-18 09:28:54]

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

[Jarin, 2015-11-18 09:28:54]

Could you take a look, please?

[Benedikt Meurer, 2015-11-18 09:30:18]

Nice. LGTM.

[Jarin, 2015-11-18 09:58:40]

The CQ bit was checked by jarin@chromium.org

[commit-bot: I haz the power, 2015-11-18 09:58:47]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1455103002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1455103002/1

[commit-bot: I haz the power, 2015-11-18 10:02:16]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-18 10:02:43]

Patchset 1 (id:??) landed as
https://crrev.com/a9fa0498e1cc4e53f63ef0f927b86793a4bd4cc6
Cr-Commit-Position: refs/heads/master@{#32075}