[X87] [Crankshaft] Fix DoMathFloor and DoMathRound code generation bug.

[X87] [Crankshaft] Fix DoMathFloor and DoMathRound code generation bug.

  The CL #35067 (https://codereview.chromium.org/1830703003) exposed one hidden bug in x87 crankshaft code generation for DoMathFloor and DoMathRound.

  The current DoMathFloor will change the default round mode of x87 FPU and then deoptimized into FC code before the default x87 FPU's round mode was restored.
  This behavior caused several test cases fail as the FC code expected to run under the default x87 FPU's round mode.

  This CL fixed this bug.

BUG=

Committed: https://crrev.com/da477bc7e284f2eb07f9f79a5214525c482d3c55
Cr-Commit-Position: refs/heads/master@{#35250}

[zhengxing.li, 2016-04-05 06:02:43]

zhengxing.li@intel.com changed reviewers:
+ chunyang.dai@intel.com, weiliang.lin@intel.com

[zhengxing.li, 2016-04-05 06:02:44]

PTAL, thanks!

[Weiliang, 2016-04-05 06:55:42]

lgtm

[zhengxing.li, 2016-04-05 06:56:19]

The CQ bit was checked by zhengxing.li@intel.com

[commit-bot: I haz the power, 2016-04-05 06:56:23]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1856303002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1856303002/1

[commit-bot: I haz the power, 2016-04-05 07:16:01]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-04-05 07:16:23]

Description was changed from

==========
[X87] [Crankshaft] Fix DoMathFloor and DoMathRound code generation bug.

  The CL #35067 (https://codereview.chromium.org/1830703003) exposed one hidden
bug in x87 crankshaft code generation for DoMathFloor and DoMathRound.

  The current DoMathFloor will change the default round mode of x87 FPU and then
deoptimized into FC code before the default x87 FPU's round mode was restored.
  This behavior caused several test cases fail as the FC code expected to run
under the default x87 FPU's round mode.

  This CL fixed this bug.

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

to

==========
[X87] [Crankshaft] Fix DoMathFloor and DoMathRound code generation bug.

  The CL #35067 (https://codereview.chromium.org/1830703003) exposed one hidden
bug in x87 crankshaft code generation for DoMathFloor and DoMathRound.

  The current DoMathFloor will change the default round mode of x87 FPU and then
deoptimized into FC code before the default x87 FPU's round mode was restored.
  This behavior caused several test cases fail as the FC code expected to run
under the default x87 FPU's round mode.

  This CL fixed this bug.

BUG=

Committed: https://crrev.com/da477bc7e284f2eb07f9f79a5214525c482d3c55
Cr-Commit-Position: refs/heads/master@{#35250}
==========

[commit-bot: I haz the power, 2016-04-05 07:16:24]

Patchset 1 (id:??) landed as
https://crrev.com/da477bc7e284f2eb07f9f79a5214525c482d3c55
Cr-Commit-Position: refs/heads/master@{#35250}