A64: Synchronize with r16756.

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index 7d33141a4f61c150320d02aaceb2c74218506b66..4a502ba2d46d6f552eafa84fe554df1ddaca6e5c 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -782,11 +782,15 @@ class HValue : public ZoneObject {
   // phase (so that live ranges will be shorter).
   virtual bool IsPurelyInformativeDefinition() { return false; }
 
-  // This method must always return the original HValue SSA definition
-  // (regardless of any iDef of this value).
+  // This method must always return the original HValue SSA definition,
+  // regardless of any chain of iDefs of this value.
   HValue* ActualValue() {
-    int index = RedefinedOperandIndex();
-    return index == kNoRedefinedOperand ? this : OperandAt(index);
+    HValue* value = this;
+    int index;
+    while ((index = value->RedefinedOperandIndex()) != kNoRedefinedOperand) {
+      value = value->OperandAt(index);
+    }
+    return value;
   }
 
   bool IsInteger32Constant();
@@ -1303,6 +1307,8 @@ class HDeoptimize V8_FINAL : public HTemplateInstruction<0> {
 // Inserts an int3/stop break instruction for debugging purposes.
 class HDebugBreak V8_FINAL : public HTemplateInstruction<0> {
  public:
+  DECLARE_INSTRUCTION_FACTORY_P0(HDebugBreak);
+
   virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
     return Representation::None();
   }