Optimize testing for an index's existence in packed Arrays

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 49d379aa0b018a977da1d520d4d91c9b3823acfb..9ce00677e22cb88e0fd09cc31241d5dac44fd960 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -11684,6 +11684,26 @@ void HOptimizedGraphBuilder::GenerateIsJSProxy(CallRuntime* call) {
 }
 
 
+void HOptimizedGraphBuilder::GenerateHasFastPackedElements(CallRuntime* call) {
+  DCHECK(call->arguments()->length() == 1);
+  CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
+  HValue* object = Pop();
+  HIfContinuation continuation;
+  IfBuilder if_fast_packed(this);
+  HValue* elements_kind = BuildGetElementsKind(object);
+  if_fast_packed.If<HCompareNumericAndBranch>(
+      elements_kind, Add<HConstant>(FAST_SMI_ELEMENTS), Token::EQ);
+  if_fast_packed.Or();
+  if_fast_packed.If<HCompareNumericAndBranch>(
+      elements_kind, Add<HConstant>(FAST_ELEMENTS), Token::EQ);
+  if_fast_packed.Or();
+  if_fast_packed.If<HCompareNumericAndBranch>(
+      elements_kind, Add<HConstant>(FAST_DOUBLE_ELEMENTS), Token::EQ);
+  if_fast_packed.CaptureContinuation(&continuation);
+  return ast_context()->ReturnContinuation(&continuation, call->id());
+}
+
+
 void HOptimizedGraphBuilder::GenerateIsNonNegativeSmi(CallRuntime* call) {
   return Bailout(kInlinedRuntimeFunctionIsNonNegativeSmi);
 }