Rewrite for-in loop as indexing loop for JavaScript indexable arrays

pkg/compiler/lib/src/ssa/nodes.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of ssa;
 
 abstract class HVisitor<R> {
   R visitAdd(HAdd node);
   R visitAwait(HAwait node);
   R visitBitAnd(HBitAnd node);
@@ skipping 2169 matching lines @@
                   TypeMask type)
       : this(variable, inputs, type);
 
   void addInput(HInstruction input) {
     assert(isInBasicBlock());
     inputs.add(input);
     assert(inputs.length <= block.predecessors.length);
     input.usedBy.add(this);
   }
 
-  toString() => 'phi';
+  toString() => 'phi $id';
   accept(HVisitor visitor) => visitor.visitPhi(this);
 }
 
 abstract class HRelational extends HInvokeBinary {
   bool usesBoolifiedInterceptor = false;
   HRelational(left, right, selector, type) : super(left, right, selector, type);
 }
 
 class HIdentity extends HRelational {
   // Cached codegen decision.
@@ skipping 974 matching lines @@
 class HDynamicType extends HRuntimeType {
   HDynamicType(DynamicType dartType, TypeMask instructionType)
       : super(const <HInstruction>[], dartType, instructionType);
 
   accept(HVisitor visitor) => visitor.visitDynamicType(this);
 
   int typeCode() => HInstruction.DYNAMIC_TYPE_TYPECODE;
 
   bool typeEquals(HInstruction other) => other is HDynamicType;
 }