Use signaling NaN for holes in fixed double arrays.

src/x64/lithium-x64.h

 // 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.
 
 #ifndef V8_X64_LITHIUM_X64_H_
 #define V8_X64_LITHIUM_X64_H_
 
 #include "src/hydrogen.h"
 #include "src/lithium.h"
 #include "src/lithium-allocator.h"
@@ skipping 1301 matching lines @@
 
 class LConstantS FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ConstantS, "constant-s")
   DECLARE_HYDROGEN_ACCESSOR(Constant)
 
   Smi* value() const { return Smi::FromInt(hydrogen()->Integer32Value()); }
 };
 
 
-class LConstantD FINAL : public LTemplateInstruction<1, 0, 1> {
+class LConstantD FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
-  explicit LConstantD(LOperand* temp) {
-    temps_[0] = temp;
-  }
-
-  LOperand* temp() { return temps_[0]; }
-
   DECLARE_CONCRETE_INSTRUCTION(ConstantD, "constant-d")
   DECLARE_HYDROGEN_ACCESSOR(Constant)
 
-  double value() const { return hydrogen()->DoubleValue(); }
+  uint64_t bits() const { return hydrogen()->DoubleValueAsBits(); }
 };
 
 
 class LConstantE FINAL : public LTemplateInstruction<1, 0, 0> {
  public:
   DECLARE_CONCRETE_INSTRUCTION(ConstantE, "constant-e")
   DECLARE_HYDROGEN_ACCESSOR(Constant)
 
   ExternalReference value() const {
     return hydrogen()->ExternalReferenceValue();
@@ skipping 1522 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(LChunkBuilder);
 };
 
 #undef DECLARE_HYDROGEN_ACCESSOR
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::int
 
 #endif  // V8_X64_LITHIUM_X64_H_