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

src/crankshaft/x87/lithium-codegen-x87.cc

Index: src/crankshaft/x87/lithium-codegen-x87.cc
diff --git a/src/crankshaft/x87/lithium-codegen-x87.cc b/src/crankshaft/x87/lithium-codegen-x87.cc
index 01df131d568858dcaa2095e6623a613b79635089..1283ac075818f1562178738d42f9cb7885f4e0e4 100644
--- a/src/crankshaft/x87/lithium-codegen-x87.cc
+++ b/src/crankshaft/x87/lithium-codegen-x87.cc
@@ -3480,6 +3480,7 @@ void LCodeGen::DoMathFloor(LMathFloor* instr) {
   __ sub(esp, Immediate(kPointerSize));
   __ fist_s(Operand(esp, 0));
   __ pop(output_reg);
+  __ X87SetRC(0x0000);
   __ X87CheckIA();
   DeoptimizeIf(equal, instr, Deoptimizer::kOverflow);
   __ fnclex();
@@ -3512,6 +3513,8 @@ void LCodeGen::DoMathRound(LMathRound* instr) {
   // Clear exception bits.
   __ fnclex();
   __ fistp_s(MemOperand(esp, 0));
+  // Restore round mode.
+  __ X87SetRC(0x0000);
   // Check overflow.
   __ X87CheckIA();
   __ pop(result);
@@ -3546,6 +3549,8 @@ void LCodeGen::DoMathRound(LMathRound* instr) {
   // Clear exception bits.
   __ fnclex();
   __ fistp_s(MemOperand(esp, 0));
+  // Restore round mode.
+  __ X87SetRC(0x0000);
   // Check overflow.
   __ X87CheckIA();
   __ pop(result);