Optimize testing for an index's existence in packed Arrays

src/hydrogen.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/hydrogen.h"
 
 #include <sstream>
 
 #include "src/v8.h"
 
@@ skipping 11647 matching lines @@
       instance_type, Add<HConstant>(FIRST_JS_PROXY_TYPE), Token::GTE);
   if_proxy.And();
   if_proxy.If<HCompareNumericAndBranch>(
       instance_type, Add<HConstant>(LAST_JS_PROXY_TYPE), Token::LTE);
 
   if_proxy.CaptureContinuation(&continuation);
   return ast_context()->ReturnContinuation(&continuation, call->id());
 }
 
 
+void HOptimizedGraphBuilder::GenerateHasFastPackedElements(CallRuntime* call) {
+  DCHECK(call->arguments()->length() == 1);
+  CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
+  HValue* object = Pop();
+  HIfContinuation continuation(graph()->CreateBasicBlock(),
+                               graph()->CreateBasicBlock());
+  IfBuilder if_not_smi(this);
+  if_not_smi.IfNot<HIsSmiAndBranch>(object);
+  if_not_smi.Then();
+  {
+    NoObservableSideEffectsScope no_effects(this);
+
+    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.JoinContinuation(&continuation);
+  }
+  if_not_smi.JoinContinuation(&continuation);
+  return ast_context()->ReturnContinuation(&continuation, call->id());
+}
+
+
 void HOptimizedGraphBuilder::GenerateIsNonNegativeSmi(CallRuntime* call) {
   return Bailout(kInlinedRuntimeFunctionIsNonNegativeSmi);
 }
 
 
 void HOptimizedGraphBuilder::GenerateIsUndetectableObject(CallRuntime* call) {
   DCHECK(call->arguments()->length() == 1);
   CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
   HValue* value = Pop();
   HIsUndetectableAndBranch* result = New<HIsUndetectableAndBranch>(value);
@@ skipping 1313 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal