ARM, ARM64: Optimize array copy

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index f1720f444247d83635c84d00a99cf2457ee0022e..a92c32e80d8878a7eb2dcd3195f569f9a4767eb6 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -83,6 +83,7 @@ class LChunkBuilder;
   V(Constant)                                  \
   V(ConstructDouble)                           \
   V(Context)                                   \
+  V(CopyElements)                              \
   V(DateField)                                 \
   V(DebugBreak)                                \
   V(DeclareGlobals)                            \
@@ -92,6 +93,7 @@ class LChunkBuilder;
   V(DummyUse)                                  \
   V(EnterInlined)                              \
   V(EnvironmentMarker)                         \
+  V(FillElements)                              \
   V(ForceRepresentation)                       \
   V(ForInCacheArray)                           \
   V(ForInPrepareMap)                           \
@@ -5713,19 +5715,21 @@ inline bool ReceiverObjectNeedsWriteBarrier(HValue* object,
     if (HAllocate::cast(object)->IsNewSpaceAllocation()) {
       return false;
     }
-    // Stores to old space allocations require no write barriers if the value is
-    // a constant provably not in new space.
-    if (value->IsConstant() && HConstant::cast(value)->NotInNewSpace()) {
-      return false;
-    }
-    // Stores to old space allocations require no write barriers if the value is
-    // an old space allocation.
-    while (value->IsInnerAllocatedObject()) {
-      value = HInnerAllocatedObject::cast(value)->base_object();
-    }
-    if (value->IsAllocate() &&
-        !HAllocate::cast(value)->IsNewSpaceAllocation()) {
-      return false;
+    if (value != NULL) {
+      // Stores to old space allocations require no write barriers if the value
+      // is a constant provably not in new space.
+      if (value->IsConstant() && HConstant::cast(value)->NotInNewSpace()) {
+        return false;
+      }
+      // Stores to old space allocations require no write barriers if the value
+      // is an old space allocation.
+      while (value->IsInnerAllocatedObject()) {
+        value = HInnerAllocatedObject::cast(value)->base_object();
+      }
+      if (value->IsAllocate() &&
+          !HAllocate::cast(value)->IsNewSpaceAllocation()) {
+        return false;
+      }
     }
   }
   return true;
@@ -6881,6 +6885,65 @@ class HStoreNamedGeneric V8_FINAL : public HTemplateInstruction<3> {
 };
 
 
+class HFillElements V8_FINAL : public HTemplateInstruction<4> {
+ public:
+  DECLARE_INSTRUCTION_FACTORY_P4(HFillElements, HValue*, HValue*,
+                                 HValue*, HValue*);
+
+  HValue* elements() { return OperandAt(0); }
+  HValue* from() { return OperandAt(1); }
+  HValue* to() { return OperandAt(2); }
+  HValue* value() { return OperandAt(3); }
+
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
+
+  DECLARE_CONCRETE_INSTRUCTION(FillElements)
+
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
+    return OperandAt(index)->representation();
+  }
+
+ private:
+  HFillElements(HValue* obj, HValue* from, HValue* to, HValue* val) {
+    SetOperandAt(0, obj);
+    SetOperandAt(1, from);
+    SetOperandAt(2, to);
+    SetOperandAt(3, val);
+  }
+};
+
+
+class HCopyElements V8_FINAL : public HTemplateInstruction<3> {
+ public:
+  DECLARE_INSTRUCTION_FACTORY_P4(HCopyElements, HValue*, HValue*, HValue*,
+                                 ElementsKind);
+
+  HValue* src() { return OperandAt(0); }
+  HValue* dst() { return OperandAt(1); }
+  HValue* length() { return OperandAt(2); }
+  ElementsKind elements_kind() const { return elements_kind_; }
+
+  virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
+
+  DECLARE_CONCRETE_INSTRUCTION(CopyElements)
+
+  virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
+    return OperandAt(index)->representation();
+  }
+
+ private:
+  HCopyElements(HValue* src, HValue* dst, HValue* length,
+                ElementsKind elements_kind)
+      : elements_kind_(elements_kind) {
+    SetOperandAt(0, src);
+    SetOperandAt(1, dst);
+    SetOperandAt(2, length);
+  }
+
+  ElementsKind elements_kind_;
+};
+
+
 class HStoreKeyed V8_FINAL
     : public HTemplateInstruction<3>, public ArrayInstructionInterface {
  public: