Inline number to string conversion for string addition into BinaryOp(Stub).

src/code-stubs-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 863 matching lines @@
   Handle<Type> right_type = stub->GetRightType(isolate());
   Handle<Type> result_type = stub->GetResultType(isolate());
 
   ASSERT(!left_type->Is(Type::None()) && !right_type->Is(Type::None()) &&
          (stub->HasSideEffects(isolate()) || !result_type->Is(Type::None())));
 
   HValue* result = NULL;
   if (stub->operation() == Token::ADD &&
       (left_type->Maybe(Type::String()) || right_type->Maybe(Type::String())) &&
       !left_type->Is(Type::String()) && !right_type->Is(Type::String())) {
-    // For the generic add stub a fast case for String add is performance
+    // For the generic add stub a fast case for string addition is performance
     // critical.
     if (left_type->Maybe(Type::String())) {
-      IfBuilder left_string(this);
-      left_string.If<HIsStringAndBranch>(left);
-      left_string.Then();
-      Push(Add<HStringAdd>(left, right, STRING_ADD_CHECK_RIGHT));
-      left_string.Else();
-      Push(AddInstruction(BuildBinaryOperation(stub->operation(),
-          left, right, left_type, right_type, result_type,
-          stub->fixed_right_arg(), true)));
-      left_string.End();
+      IfBuilder if_leftisstring(this);
+      if_leftisstring.If<HIsStringAndBranch>(left);
+      if_leftisstring.Then();
+      {
+        Push(AddInstruction(BuildBinaryOperation(
+                    stub->operation(), left, right,
+                    handle(Type::String(), isolate()), right_type,
+                    result_type, stub->fixed_right_arg(), true)));
+      }
+      if_leftisstring.Else();
+      {
+        Push(AddInstruction(BuildBinaryOperation(
+                    stub->operation(), left, right,
+                    left_type, right_type, result_type,
+                    stub->fixed_right_arg(), true)));
+      }
+      if_leftisstring.End();
       result = Pop();
     } else {
-      IfBuilder right_string(this);
-      right_string.If<HIsStringAndBranch>(right);
-      right_string.Then();
-      Push(Add<HStringAdd>(left, right, STRING_ADD_CHECK_LEFT));
-      right_string.Else();
-      Push(AddInstruction(BuildBinaryOperation(stub->operation(),
-          left, right, left_type, right_type, result_type,
-          stub->fixed_right_arg(), true)));
-      right_string.End();
+      IfBuilder if_rightisstring(this);
+      if_rightisstring.If<HIsStringAndBranch>(right);
+      if_rightisstring.Then();
+      {
+        Push(AddInstruction(BuildBinaryOperation(
+                    stub->operation(), left, right,
+                    left_type, handle(Type::String(), isolate()),
+                    result_type, stub->fixed_right_arg(), true)));
+      }
+      if_rightisstring.Else();
+      {
+        Push(AddInstruction(BuildBinaryOperation(
+                    stub->operation(), left, right,
+                    left_type, right_type, result_type,
+                    stub->fixed_right_arg(), true)));
+      }
+      if_rightisstring.End();
       result = Pop();
     }
   } else {
-    result = AddInstruction(BuildBinaryOperation(stub->operation(),
-        left, right, left_type, right_type, result_type,
-        stub->fixed_right_arg(), true));
+    result = AddInstruction(BuildBinaryOperation(
+            stub->operation(), left, right,
+            left_type, right_type, result_type,
+            stub->fixed_right_arg(), true));
   }
 
   // If we encounter a generic argument, the number conversion is
   // observable, thus we cannot afford to bail out after the fact.
   if (!stub->HasSideEffects(isolate())) {
     if (result_type->Is(Type::Smi())) {
       if (stub->operation() == Token::SHR) {
         // TODO(olivf) Replace this by a SmiTagU Instruction.
         // 0x40000000: this number would convert to negative when interpreting
         // the register as signed value;
@@ skipping 319 matching lines @@
   return js_function;
 }
 
 
 Handle<Code> FastNewClosureStub::GenerateCode(Isolate* isolate) {
   return DoGenerateCode(isolate, this);
 }
 
 
 } }  // namespace v8::internal