Revert "dart2js cps: Refactor and optimize string concatenations."

pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart

Index: pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart
diff --git a/pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart b/pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart
index 523314dff9a8ff5a42e894a276e20df42aae5f3f..41b7bcda507566afd1ae51043dc2fd654d819fc0 100644
--- a/pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart
+++ b/pkg/compiler/lib/src/tree_ir/tree_ir_nodes.dart
@@ -267,16 +267,31 @@ class InvokeConstructor extends Expression implements Invoke {
   }
 }
 
+/// Calls [toString] on each argument and concatenates the results.
+class ConcatenateStrings extends Expression {
+  final List<Expression> arguments;
+
+  ConcatenateStrings(this.arguments);
+
+  accept(ExpressionVisitor visitor) => visitor.visitConcatenateStrings(this);
+  accept1(ExpressionVisitor1 visitor, arg) {
+    return visitor.visitConcatenateStrings(this, arg);
+  }
+}
+
 /**
  * A constant.
  */
 class Constant extends Expression {
+  final ConstantExpression expression;
   final values.ConstantValue value;
 
-  Constant(this.value);
+  Constant(this.expression, this.value);
 
   Constant.bool(values.BoolConstantValue constantValue)
-      : value = constantValue;
+      : expression = new BoolConstantExpression(
+          constantValue.primitiveValue),
+        value = constantValue;
 
   accept(ExpressionVisitor visitor) => visitor.visitConstant(this);
   accept1(ExpressionVisitor1 visitor, arg) => visitor.visitConstant(this, arg);
@@ -843,6 +858,7 @@ abstract class ExpressionVisitor<E> {
   E visitInvokeMethod(InvokeMethod node);
   E visitInvokeMethodDirectly(InvokeMethodDirectly node);
   E visitInvokeConstructor(InvokeConstructor node);
+  E visitConcatenateStrings(ConcatenateStrings node);
   E visitConstant(Constant node);
   E visitThis(This node);
   E visitConditional(Conditional node);
@@ -874,6 +890,7 @@ abstract class ExpressionVisitor1<E, A> {
   E visitInvokeMethod(InvokeMethod node, A arg);
   E visitInvokeMethodDirectly(InvokeMethodDirectly node, A arg);
   E visitInvokeConstructor(InvokeConstructor node, A arg);
+  E visitConcatenateStrings(ConcatenateStrings node, A arg);
   E visitConstant(Constant node, A arg);
   E visitThis(This node, A arg);
   E visitConditional(Conditional node, A arg);
@@ -966,6 +983,10 @@ abstract class RecursiveVisitor implements StatementVisitor, ExpressionVisitor {
     node.arguments.forEach(visitExpression);
   }
 
+  visitConcatenateStrings(ConcatenateStrings node) {
+    node.arguments.forEach(visitExpression);
+  }
+
   visitConstant(Constant node) {}
 
   visitThis(This node) {}
@@ -1151,6 +1172,11 @@ class RecursiveTransformer extends Transformer {
     return node;
   }
 
+  visitConcatenateStrings(ConcatenateStrings node) {
+    _replaceExpressions(node.arguments);
+    return node;
+  }
+
   visitConstant(Constant node) => node;
 
   visitThis(This node) => node;