[Crankshaft] Don't add an instruction twice for %_StringGetLength.

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 6822 matching lines @@
       return Add<HConstant>(c_string->StringValue()->map()->instance_type());
     }
   }
   return Add<HLoadNamedField>(
       Add<HLoadNamedField>(string, nullptr, HObjectAccess::ForMap()), nullptr,
       HObjectAccess::ForMapInstanceType());
 }
 
 
 HInstruction* HGraphBuilder::AddLoadStringLength(HValue* string) {
+  return AddInstruction(BuildLoadStringLength(string));
+}
+
+
+HInstruction* HGraphBuilder::BuildLoadStringLength(HValue* string) {
   if (string->IsConstant()) {
     HConstant* c_string = HConstant::cast(string);
     if (c_string->HasStringValue()) {
-      return Add<HConstant>(c_string->StringValue()->length());
+      return New<HConstant>(c_string->StringValue()->length());
     }
   }
-  return Add<HLoadNamedField>(string, nullptr,
+  return New<HLoadNamedField>(string, nullptr,
                               HObjectAccess::ForStringLength());
 }
 
 
 HInstruction* HOptimizedGraphBuilder::BuildNamedGeneric(
     PropertyAccessType access_type, Expression* expr, HValue* object,
     Handle<String> name, HValue* value, bool is_uninitialized) {
   if (is_uninitialized) {
     Add<HDeoptimize>(
         Deoptimizer::kInsufficientTypeFeedbackForGenericNamedAccess,
@@ skipping 5012 matching lines @@
   PushArgumentsFromEnvironment(call->arguments()->length());
   HCallStub* result = New<HCallStub>(CodeStub::StringCompare, 2);
   return ast_context()->ReturnInstruction(result, call->id());
 }
 
 
 void HOptimizedGraphBuilder::GenerateStringGetLength(CallRuntime* call) {
   DCHECK(call->arguments()->length() == 1);
   CHECK_ALIVE(VisitForValue(call->arguments()->at(0)));
   HValue* string = Pop();
-  HInstruction* result = AddLoadStringLength(string);
+  HInstruction* result = BuildLoadStringLength(string);
   return ast_context()->ReturnInstruction(result, call->id());
 }
 
 
 // Support for direct calls from JavaScript to native RegExp code.
 void HOptimizedGraphBuilder::GenerateRegExpExec(CallRuntime* call) {
   DCHECK_EQ(4, call->arguments()->length());
   CHECK_ALIVE(VisitExpressions(call->arguments()));
   PushArgumentsFromEnvironment(call->arguments()->length());
   HCallStub* result = New<HCallStub>(CodeStub::RegExpExec, 4);
@@ skipping 1510 matching lines @@
   if (ShouldProduceTraceOutput()) {
     isolate()->GetHTracer()->TraceHydrogen(name(), graph_);
   }
 
 #ifdef DEBUG
   graph_->Verify(false);  // No full verify.
 #endif
 }
 
 } }  // namespace v8::internal