Use xorps xmm1, xmm1 to creat a 0.0 cconstant. Add to utils a bitwise double test.

runtime/vm/intermediate_language_ia32.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_IA32.
 #if defined(TARGET_ARCH_IA32)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/dart_entry.h"
@@ skipping 144 matching lines @@
   if (kNumTemps == 1) {
     locs->set_temp(0, Location::RequiresRegister());
   }
   return locs;
 }
 
 
 void UnboxedConstantInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   // The register allocator drops constant definitions that have no uses.
   if (!locs()->out(0).IsInvalid()) {
+     XmmRegister result = locs()->out(0).fpu_reg();
     if (constant_address() == 0) {
       Register boxed = locs()->temp(0).reg();
-      XmmRegister result = locs()->out(0).fpu_reg();
       __ LoadObjectSafely(boxed, value());
       __ movsd(result, FieldAddress(boxed, Double::value_offset()));
+    } else if (Utils::DoublesBitEqual(Double::Cast(value()).value(), 0.0)) {
+      __ xorps(result, result);
     } else {
-      XmmRegister result = locs()->out(0).fpu_reg();
       __ movsd(result, Address::Absolute(constant_address()));
     }
   }
 }
 
 
 LocationSummary* AssertAssignableInstr::MakeLocationSummary(bool opt) const {
   const intptr_t kNumInputs = 3;
   const intptr_t kNumTemps = 0;
   LocationSummary* summary =
@@ skipping 5848 matching lines @@
                          PcDescriptors::kOther,
                          locs());
   __ Drop(ArgumentCount());  // Discard arguments.
 }
 
 }  // namespace dart
 
 #undef __
 
 #endif  // defined TARGET_ARCH_IA32