Never hchange nan-hole to hole or hole to nan-hole.

src/x64/lithium-x64.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 56 matching lines @@
   V(CheckMaps)                                  \
   V(CheckMapValue)                              \
   V(CheckNonSmi)                                \
   V(CheckSmi)                                   \
   V(ClampDToUint8)                              \
   V(ClampIToUint8)                              \
   V(ClampTToUint8)                              \
   V(ClassOfTestAndBranch)                       \
   V(CompareNumericAndBranch)                    \
   V(CmpObjectEqAndBranch)                       \
+  V(CmpHoleAndBranch)                           \
   V(CmpMapAndBranch)                            \
   V(CmpT)                                       \
   V(ConstantD)                                  \
   V(ConstantE)                                  \
   V(ConstantI)                                  \
   V(ConstantS)                                  \
   V(ConstantT)                                  \
   V(Context)                                    \
   V(DateField)                                  \
   V(DebugBreak)                                 \
@@ skipping 729 matching lines @@
 class LCmpObjectEqAndBranch: public LControlInstruction<2, 0> {
  public:
   LCmpObjectEqAndBranch(LOperand* left, LOperand* right) {
     inputs_[0] = left;
     inputs_[1] = right;
   }
 
   LOperand* left() { return inputs_[0]; }
   LOperand* right() { return inputs_[1]; }
 
-  DECLARE_CONCRETE_INSTRUCTION(CmpObjectEqAndBranch,
-                               "cmp-object-eq-and-branch")
+  DECLARE_CONCRETE_INSTRUCTION(CmpObjectEqAndBranch, "cmp-object-eq-and-branch")
 };
 
 
+class LCmpHoleAndBranch: public LControlInstruction<1, 0> {
+ public:
+  explicit LCmpHoleAndBranch(LOperand* object) {
+    inputs_[0] = object;
+  }
+
+  LOperand* object() { return inputs_[0]; }
+
+  DECLARE_CONCRETE_INSTRUCTION(CmpHoleAndBranch, "cmp-hole-and-branch")
+  DECLARE_HYDROGEN_ACCESSOR(CompareHoleAndBranch)
+};
+
+
 class LIsObjectAndBranch: public LControlInstruction<1, 0> {
  public:
   explicit LIsObjectAndBranch(LOperand* value) {
     inputs_[0] = value;
   }
 
   LOperand* value() { return inputs_[0]; }
 
   DECLARE_CONCRETE_INSTRUCTION(IsObjectAndBranch, "is-object-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(IsObjectAndBranch)
@@ skipping 1814 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(LChunkBuilder);
 };
 
 #undef DECLARE_HYDROGEN_ACCESSOR
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::int
 
 #endif  // V8_X64_LITHIUM_X64_H_