[wasm] Fixed float-to-int32 conversion to match the spec.

[wasm] Fixed float-to-int32 conversion to match the spec.

The new implementation detects if the input value is outside i32 range
and traps it that case.

The range check is done as follows:
The input value is converted to int32 and then back to float. If the
result is the same as the truncated input value, then the input value
is within int32 range.

R=bmeurer@chromium.org

Committed: https://crrev.com/dcac1f144e4c8d37338ce9ee94cc1704e81fb0b7
Cr-Commit-Position: refs/heads/master@{#32984}

[Benedikt Meurer, 2015-12-21 10:19:27]

I'm a bit scared that I'm wasm OWNER now :-)
But this one LGTM

[ahaas, 2015-12-21 10:21:04]

The CQ bit was checked by ahaas@chromium.org

[commit-bot: I haz the power, 2015-12-21 10:21:11]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1537393003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1537393003/1

[commit-bot: I haz the power, 2015-12-21 10:52:57]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-12-21 10:53:21]

Description was changed from

==========
[wasm] Fixed float-to-int32 conversion to match the spec.

The new implementation detects if the input value is outside i32 range
and traps it that case.

The range check is done as follows:
The input value is converted to int32 and then back to float. If the
result is the same as the truncated input value, then the input value
is within int32 range.

R=bmeurer@chromium.org
==========

to

==========
[wasm] Fixed float-to-int32 conversion to match the spec.

The new implementation detects if the input value is outside i32 range
and traps it that case.

The range check is done as follows:
The input value is converted to int32 and then back to float. If the
result is the same as the truncated input value, then the input value
is within int32 range.

R=bmeurer@chromium.org

Committed: https://crrev.com/dcac1f144e4c8d37338ce9ee94cc1704e81fb0b7
Cr-Commit-Position: refs/heads/master@{#32984}
==========

[commit-bot: I haz the power, 2015-12-21 10:53:22]

Patchset 1 (id:??) landed as
https://crrev.com/dcac1f144e4c8d37338ce9ee94cc1704e81fb0b7
Cr-Commit-Position: refs/heads/master@{#32984}