Introduce %_IsMinusZero.

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 54 matching lines @@
   V(CheckInstanceType)                          \
   V(CheckMaps)                                  \
   V(CheckMapValue)                              \
   V(CheckNonSmi)                                \
   V(CheckSmi)                                   \
   V(CheckValue)                                 \
   V(ClampDToUint8)                              \
   V(ClampIToUint8)                              \
   V(ClampTToUint8)                              \
   V(ClassOfTestAndBranch)                       \
+  V(CompareMinusZeroAndBranch)                  \
   V(CompareNumericAndBranch)                    \
   V(CmpObjectEqAndBranch)                       \
   V(CmpHoleAndBranch)                           \
   V(CmpMapAndBranch)                            \
   V(CmpT)                                       \
   V(ConstantD)                                  \
   V(ConstantE)                                  \
   V(ConstantI)                                  \
   V(ConstantS)                                  \
   V(ConstantT)                                  \
@@ skipping 782 matching lines @@
     inputs_[0] = object;
   }
 
   LOperand* object() { return inputs_[0]; }
 
   DECLARE_CONCRETE_INSTRUCTION(CmpHoleAndBranch, "cmp-hole-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(CompareHoleAndBranch)
 };
 
 
+class LCompareMinusZeroAndBranch V8_FINAL : public LControlInstruction<1, 0> {
+ public:
+  explicit LCompareMinusZeroAndBranch(LOperand* value) {
+    inputs_[0] = value;
+  }
+
+  LOperand* value() { return inputs_[0]; }
+
+  DECLARE_CONCRETE_INSTRUCTION(CompareMinusZeroAndBranch,
+                               "cmp-minus-zero-and-branch")
+  DECLARE_HYDROGEN_ACCESSOR(CompareMinusZeroAndBranch)
+};
+
+
+
 class LIsObjectAndBranch V8_FINAL : 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 1961 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(LChunkBuilder);
 };
 
 #undef DECLARE_HYDROGEN_ACCESSOR
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::int
 
 #endif  // V8_X64_LITHIUM_X64_H_