Set the FPU precision control to double-precision.

src/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.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_X87
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 2254 matching lines @@
 }
 
 
 void LCodeGen::DoArithmeticD(LArithmeticD* instr) {
   X87Register left = ToX87Register(instr->left());
   X87Register right = ToX87Register(instr->right());
   X87Register result = ToX87Register(instr->result());
   if (instr->op() != Token::MOD) {
     X87PrepareBinaryOp(left, right, result);
   }
+  // Set the precision control to double-precision.
+  __ X87SetFPUCW(0x027F);
   switch (instr->op()) {
     case Token::ADD:
       __ fadd_i(1);
       break;
     case Token::SUB:
       __ fsub_i(1);
       break;
     case Token::MUL:
       __ fmul_i(1);
       break;
@@ skipping 14 matching lines @@
 
       // Return value is in st(0) on ia32.
       X87CommitWrite(result);
       break;
     }
     default:
       UNREACHABLE();
       break;
   }
 
-  // Only always explicitly storing to memory to force the round-down for double
-  // arithmetic.
-  __ lea(esp, Operand(esp, -kDoubleSize));
-  __ fstp_d(Operand(esp, 0));
-  __ fld_d(Operand(esp, 0));
-  __ lea(esp, Operand(esp, kDoubleSize));
+  __ X87SetFPUCW(0x037F);
 }
 
 
 void LCodeGen::DoArithmeticT(LArithmeticT* instr) {
   DCHECK(ToRegister(instr->context()).is(esi));
   DCHECK(ToRegister(instr->left()).is(edx));
   DCHECK(ToRegister(instr->right()).is(eax));
   DCHECK(ToRegister(instr->result()).is(eax));
 
   Handle<Code> code =
@@ skipping 3974 matching lines @@
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X87