Reduce the amount of full code generated to fill out array literals.

src/hydrogen.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 6082 matching lines @@
     literal = AddInstruction(
         new(zone()) HCallRuntime(context,
                                  isolate()->factory()->empty_string(),
                                  Runtime::FunctionForId(function_id),
                                  3));
   }
 
   // The array is expected in the bailout environment during computation
   // of the property values and is the value of the entire expression.
   Push(literal);
+  // The literal index is on the stack, too.
+  Push(AddInstruction(
+      new(zone()) HConstant(expr->literal_index(), Representation::Smi())));

[Michael Starzinger, 2013/06/13 13:57:27]

I would just not specify a particular representation in HConstant constructor
and let the inferencer figure it out.

[Sven Panne, 2013/06/14 06:04:32]

Done.

 
   HInstruction* elements = NULL;
 
   for (int i = 0; i < length; i++) {
     Expression* subexpr = subexprs->at(i);
     // If the subexpression is a literal or a simple materialized literal it
     // is already set in the cloned array.
     if (CompileTimeValue::IsCompileTimeValue(subexpr)) continue;
 
     CHECK_ALIVE(VisitForValue(subexpr));
@@ skipping 17 matching lines @@
             value,
             boilerplate_elements_kind));
         break;
       default:
         UNREACHABLE();
         break;
     }
 
     AddSimulate(expr->GetIdForElement(i));
   }
+
+  Drop(1);  // array literal index
   return ast_context()->ReturnValue(Pop());
 }
 
 
 // Sets the lookup result and returns true if the load/store can be inlined.
 static bool ComputeLoadStoreField(Handle<Map> type,
                                   Handle<String> name,
                                   LookupResult* lookup,
                                   bool is_store) {
   if (type->has_named_interceptor()) {
@@ skipping 5464 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify(false);  // No full verify.
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal