Introduce %_IsMinusZero.

src/hydrogen-instructions.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 82 matching lines @@
   V(CheckInstanceType)                         \
   V(CheckMaps)                                 \
   V(CheckMapValue)                             \
   V(CheckSmi)                                  \
   V(CheckValue)                                \
   V(ClampToUint8)                              \
   V(ClassOfTestAndBranch)                      \
   V(CompareNumericAndBranch)                   \
   V(CompareHoleAndBranch)                      \
   V(CompareGeneric)                            \
+  V(CompareMinusZeroAndBranch)                 \
   V(CompareObjectEqAndBranch)                  \
   V(CompareMap)                                \
   V(Constant)                                  \
   V(Context)                                   \
   V(DateField)                                 \
   V(DebugBreak)                                \
   V(DeclareGlobals)                            \
   V(Deoptimize)                                \
   V(Div)                                       \
   V(DummyUse)                                  \
@@ skipping 4045 matching lines @@
   HCompareHoleAndBranch(HValue* value,
                         HBasicBlock* true_target = NULL,
                         HBasicBlock* false_target = NULL)
       : HUnaryControlInstruction(value, true_target, false_target) {
     SetFlag(kFlexibleRepresentation);
     SetFlag(kAllowUndefinedAsNaN);
   }
 };
 
 
+class HCompareMinusZeroAndBranch V8_FINAL : public HUnaryControlInstruction {
+ public:
+  DECLARE_INSTRUCTION_FACTORY_P1(HCompareMinusZeroAndBranch, HValue*);
+
+  virtual void InferRepresentation(
+      HInferRepresentationPhase* h_infer) V8_OVERRIDE;
+
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
+    return representation();
+  }
+
+  virtual bool KnownSuccessorBlock(HBasicBlock** block) V8_OVERRIDE;
+
+  DECLARE_CONCRETE_INSTRUCTION(CompareMinusZeroAndBranch)
+
+ private:
+  explicit HCompareMinusZeroAndBranch(HValue* value)
+      : HUnaryControlInstruction(value, NULL, NULL) {
+  }
+};
+
+
 class HCompareObjectEqAndBranch : public HTemplateControlInstruction<2, 2> {
  public:
   HCompareObjectEqAndBranch(HValue* left,
                             HValue* right,
                             HBasicBlock* true_target = NULL,
                             HBasicBlock* false_target = NULL) {
     // TODO(danno): make this private when the IfBuilder properly constructs
     // control flow instructions.
     ASSERT(!left->IsConstant() ||
            (!HConstant::cast(left)->HasInteger32Value() ||
@@ skipping 3076 matching lines @@
   virtual bool IsDeletable() const V8_OVERRIDE { return true; }
 };
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_