Introduce %_IsMinusZero.

src/arm/lithium-arm.h

Index: src/arm/lithium-arm.h
diff --git a/src/arm/lithium-arm.h b/src/arm/lithium-arm.h
index 559f26e5da886f9e2c61bdff1a2ffc515431d453..f67747b5d0af7b979da7197e9ca7b03e0adfc7a2 100644
--- a/src/arm/lithium-arm.h
+++ b/src/arm/lithium-arm.h
@@ -72,6 +72,7 @@ class LCodeGen;
   V(ClampIToUint8)                              \
   V(ClampTToUint8)                              \
   V(ClassOfTestAndBranch)                       \
+  V(CompareMinusZeroAndBranch)                  \
   V(CompareNumericAndBranch)                    \
   V(CmpObjectEqAndBranch)                       \
   V(CmpHoleAndBranch)                           \
@@ -928,6 +929,22 @@ class LCmpHoleAndBranch V8_FINAL : public LControlInstruction<1, 0> {
 };
 
 
+class LCompareMinusZeroAndBranch V8_FINAL : public LControlInstruction<1, 1> {
+ public:
+  LCompareMinusZeroAndBranch(LOperand* value, LOperand* temp) {
+    inputs_[0] = value;
+    temps_[0] = temp;
+  }
+
+  LOperand* value() { return inputs_[0]; }
+  LOperand* temp() { return temps_[0]; }
+
+  DECLARE_CONCRETE_INSTRUCTION(CompareMinusZeroAndBranch,
+                               "cmp-minus-zero-and-branch")
+  DECLARE_HYDROGEN_ACCESSOR(CompareMinusZeroAndBranch)
+};
+
+
 class LIsObjectAndBranch V8_FINAL : public LControlInstruction<1, 1> {
  public:
   LIsObjectAndBranch(LOperand* value, LOperand* temp) {