Add fake data dependencies (instead of disabling GVN) to fix code motion

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index 93a7073b6ad14a1b3f16c4d481eeb5f4328a1ad4..0149b57776caf8a604d89f4ea330aa487f7c2f52 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -1661,12 +1661,14 @@ class HCallRuntime: public HCall<1> {
 };
 
 
-class HJSArrayLength: public HUnaryOperation {
+class HJSArrayLength: public HTemplateInstruction<2> {
  public:
-  explicit HJSArrayLength(HValue* value) : HUnaryOperation(value) {
+  HJSArrayLength(HValue* value, HValue* typecheck) {
     // The length of an array is stored as a tagged value in the array
     // object. It is guaranteed to be 32 bit integer, but it can be
     // represented as either a smi or heap number.
+    SetOperandAt(0, value);
+    SetOperandAt(1, typecheck);
     set_representation(Representation::Tagged());
     SetFlag(kUseGVN);
     SetFlag(kDependsOnArrayLengths);
@@ -1677,6 +1679,8 @@ class HJSArrayLength: public HUnaryOperation {
     return Representation::Tagged();
   }
 
+  HValue* value() { return OperandAt(0); }
+
   DECLARE_CONCRETE_INSTRUCTION(JSArrayLength)
 
  protected:
@@ -1907,10 +1911,6 @@ class HCheckMap: public HUnaryOperation {
   virtual void PrintDataTo(StringStream* stream);
   virtual HType CalculateInferredType();
 
-#ifdef DEBUG
-  virtual void Verify();
-#endif
-
   Handle<Map> map() const { return map_; }
 
   DECLARE_CONCRETE_INSTRUCTION(CheckMap)
@@ -1978,10 +1978,6 @@ class HCheckInstanceType: public HUnaryOperation {
     return Representation::Tagged();
   }
 
-#ifdef DEBUG
-  virtual void Verify();
-#endif
-
   virtual HValue* Canonicalize();
 
   bool is_interval_check() const { return check_ <= LAST_INTERVAL_CHECK; }
@@ -2456,10 +2452,6 @@ class HBoundsCheck: public HTemplateInstruction<2> {
     return Representation::Integer32();
   }
 
-#ifdef DEBUG
-  virtual void Verify();
-#endif
-
   HValue* index() { return OperandAt(0); }
   HValue* length() { return OperandAt(1); }