dart2js cps: Store the TypeMask for each primitive in a field.

pkg/compiler/lib/src/cps_ir/mutable_ssa.dart

 // Copyright (c) 2015, 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.
 
 library dart2js.cps_ir.mutable_ssa;
 
 import 'cps_ir_nodes.dart';
 import 'optimizers.dart';
 
 /// Determines which mutable variables should be rewritten to phi assignments
@@ skipping 173 matching lines @@
         for (Continuation cont in node.continuations) {
           if (!isJoinContinuation(cont)) continue;
           // Create a phi parameter for every mutable variable in scope.
           // At the same time, build the environment to use for processing
           // the continuation (mapping mutables to phi parameters).
           continuationPhiCount[cont] = mutableVariables.length;
           Map<MutableVariable, Primitive> environment =
               <MutableVariable, Primitive>{};
           for (MutableVariable variable in mutableVariables) {
             Parameter phi = new Parameter(variable.hint);
+            phi.type = variable.type;
             cont.parameters.add(phi);
             phi.parent = cont;
             environment[variable] = phi;
           }
           stack.add(new ContinuationItem(cont, environment));
         }
       } else if (node is LetHandler) {
         // Process the catch block later and continue into the try block.
         // We can use the same environment object for the try and catch blocks.
         // The current environment bindings cannot change inside the try block
@@ skipping 42 matching lines @@
 class VariableItem extends StackItem {}
 
 /// Represents a yet unprocessed continuation together with the
 /// environment in which to process it.
 class ContinuationItem extends StackItem {
   final Continuation continuation;
   final Map<MutableVariable, Primitive> environment;
 
   ContinuationItem(this.continuation, this.environment);
 }