Start using the overwrite mode from the full codegens to generate...

src/x64/codegen-x64.cc

 // Copyright 2010 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 4991 matching lines @@
   ASSERT(slot != NULL);
 
   // Evaluate the right-hand side.
   if (node->is_compound()) {
     // For a compound assignment the right-hand side is a binary operation
     // between the current property value and the actual right-hand side.
     LoadFromSlotCheckForArguments(slot, NOT_INSIDE_TYPEOF);
     Load(node->value());
 
     // Perform the binary operation.
-    bool overwrite_value =
-        (node->value()->AsBinaryOperation() != NULL &&
-         node->value()->AsBinaryOperation()->ResultOverwriteAllowed());
+    bool overwrite_value = node->value()->ResultOverwriteAllowed();
     // Construct the implicit binary operation.
     BinaryOperation expr(node);
     GenericBinaryOperation(&expr,
                            overwrite_value ? OVERWRITE_RIGHT : NO_OVERWRITE);
   } else {
     // For non-compound assignment just load the right-hand side.
     Load(node->value());
   }
 
   // Perform the assignment.
@@ skipping 68 matching lines @@
       // Freeing rax causes the code generator to load the global into it.
       frame_->Spill(rax);
       LoadGlobal();
     } else {
       frame()->Dup();
     }
     Result value = EmitNamedLoad(name, var != NULL);
     frame()->Push(&value);
     Load(node->value());
 
-    bool overwrite_value =
-        (node->value()->AsBinaryOperation() != NULL &&
-         node->value()->AsBinaryOperation()->ResultOverwriteAllowed());
+    bool overwrite_value = node->value()->ResultOverwriteAllowed();
     // Construct the implicit binary operation.
     BinaryOperation expr(node);
     GenericBinaryOperation(&expr,
                            overwrite_value ? OVERWRITE_RIGHT : NO_OVERWRITE);
   } else {
     // For non-compound assignment just load the right-hand side.
     Load(node->value());
   }
 
   // Stack layout:
@@ skipping 79 matching lines @@
     // For a compound assignment the right-hand side is a binary operation
     // between the current property value and the actual right-hand side.
     // Duplicate receiver and key for loading the current property value.
     frame()->PushElementAt(1);
     frame()->PushElementAt(1);
     Result value = EmitKeyedLoad();
     frame()->Push(&value);
     Load(node->value());
 
     // Perform the binary operation.
-    bool overwrite_value =
-        (node->value()->AsBinaryOperation() != NULL &&
-         node->value()->AsBinaryOperation()->ResultOverwriteAllowed());
+    bool overwrite_value = node->value()->ResultOverwriteAllowed();
     BinaryOperation expr(node);
     GenericBinaryOperation(&expr,
                            overwrite_value ? OVERWRITE_RIGHT : NO_OVERWRITE);
   } else {
     // For non-compound assignment just load the right-hand side.
     Load(node->value());
   }
 
   // Stack layout:
   // [tos]   : value
@@ skipping 2132 matching lines @@
         expression->AsLiteral()->IsNull())) {
       // Omit evaluating the value of the primitive literal.
       // It will be discarded anyway, and can have no side effect.
       frame_->Push(Factory::undefined_value());
     } else {
       Load(node->expression());
       frame_->SetElementAt(0, Factory::undefined_value());
     }
 
   } else {
-    bool can_overwrite =
-      (node->expression()->AsBinaryOperation() != NULL &&
-       node->expression()->AsBinaryOperation()->ResultOverwriteAllowed());
+    bool can_overwrite = node->expression()->ResultOverwriteAllowed();
     UnaryOverwriteMode overwrite =
         can_overwrite ? UNARY_OVERWRITE : UNARY_NO_OVERWRITE;
     bool no_negative_zero = node->expression()->no_negative_zero();
     Load(node->expression());
     switch (op) {
       case Token::NOT:
       case Token::DELETE:
       case Token::TYPEOF:
         UNREACHABLE();  // handled above
         break;
@@ skipping 397 matching lines @@
 
 void CodeGenerator::VisitBinaryOperation(BinaryOperation* node) {
   Comment cmnt(masm_, "[ BinaryOperation");
 
   if (node->op() == Token::AND || node->op() == Token::OR) {
     GenerateLogicalBooleanOperation(node);
   } else {
     // NOTE: The code below assumes that the slow cases (calls to runtime)
     // never return a constant/immutable object.
     OverwriteMode overwrite_mode = NO_OVERWRITE;
-    if (node->left()->AsBinaryOperation() != NULL &&
-        node->left()->AsBinaryOperation()->ResultOverwriteAllowed()) {
+    if (node->left()->ResultOverwriteAllowed()) {
       overwrite_mode = OVERWRITE_LEFT;
-    } else if (node->right()->AsBinaryOperation() != NULL &&
-               node->right()->AsBinaryOperation()->ResultOverwriteAllowed()) {
+    } else if (node->right()->ResultOverwriteAllowed()) {
       overwrite_mode = OVERWRITE_RIGHT;
     }
 
     if (node->left()->IsTrivial()) {
       Load(node->right());
       Result right = frame_->Pop();
       frame_->Push(node->left());
       frame_->Push(&right);
     } else {
       Load(node->left());
@@ skipping 1087 matching lines @@
 #undef __
 
 void RecordWriteStub::Generate(MacroAssembler* masm) {
   masm->RecordWriteHelper(object_, addr_, scratch_);
   masm->ret(0);
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64