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

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

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_X87
 
 #include "src/crankshaft/x87/lithium-codegen-x87.h"
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 3462 matching lines @@
   }
 
   // Positive input.
   // rc=01B, round down.
   __ bind(&not_minus_zero);
   __ fnclex();
   __ X87SetRC(0x0400);
   __ sub(esp, Immediate(kPointerSize));
   __ fist_s(Operand(esp, 0));
   __ pop(output_reg);
+  __ X87SetRC(0x0000);
   __ X87CheckIA();
   DeoptimizeIf(equal, instr, Deoptimizer::kOverflow);
   __ fnclex();
   __ X87SetRC(0x0000);
   __ bind(&done);
 }
 
 
 void LCodeGen::DoMathRound(LMathRound* instr) {
   X87Register input_reg = ToX87Register(instr->value());
@@ skipping 12 matching lines @@
 
   // Use rounds towards zero, since 0.5 <= x, we use floor(0.5 + x)
   __ fld(0);
   __ fadd_d(Operand::StaticVariable(one_half));
   // rc=11B, round toward zero.
   __ X87SetRC(0x0c00);
   __ sub(esp, Immediate(kPointerSize));
   // Clear exception bits.
   __ fnclex();
   __ fistp_s(MemOperand(esp, 0));
+  // Restore round mode.
+  __ X87SetRC(0x0000);
   // Check overflow.
   __ X87CheckIA();
   __ pop(result);
   DeoptimizeIf(equal, instr, Deoptimizer::kConversionOverflow);
   __ fnclex();
   // Restore round mode.
   __ X87SetRC(0x0000);
   __ jmp(&done);
 
   __ bind(&below_one_half);
@@ skipping 14 matching lines @@
 
   __ bind(&below_minus_one_half);
   __ fld(0);
   __ fadd_d(Operand::StaticVariable(one_half));
   // rc=01B, round down.
   __ X87SetRC(0x0400);
   __ sub(esp, Immediate(kPointerSize));
   // Clear exception bits.
   __ fnclex();
   __ fistp_s(MemOperand(esp, 0));
+  // Restore round mode.
+  __ X87SetRC(0x0000);
   // Check overflow.
   __ X87CheckIA();
   __ pop(result);
   DeoptimizeIf(equal, instr, Deoptimizer::kConversionOverflow);
   __ fnclex();
   // Restore round mode.
   __ X87SetRC(0x0000);
 
   __ bind(&done);
 }
@@ skipping 2261 matching lines @@
   __ bind(deferred->exit());
   __ bind(&done);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X87