dart2js cps: Do not remove unused refinements.

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

 // Copyright (c) 2014, 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.shrinking_reductions;
 
 import 'cps_ir_nodes.dart';
 import 'optimizers.dart';
+import 'cps_fragment.dart';
 
 /**
  * [ShrinkingReducer] applies shrinking reductions to CPS terms as described
  * in 'Compiling with Continuations, Continued' by Andrew Kennedy.
  */
 class ShrinkingReducer extends Pass {
   String get passName => 'Shrinking reductions';
 
   List<_ReductionTask> _worklist;
 
@@ skipping 65 matching lines @@
         assert(false);
     }
   }
 
   /// Applies the dead-val reduction:
   ///   letprim x = V in E -> E (x not free in E).
   void _reduceDeadVal(_ReductionTask task) {
     assert(_isDeadVal(task.node));
 
     // Remove dead primitive.
-    LetPrim letPrim = task.node;;
+    LetPrim letPrim = task.node;
+    destroyRefinementsOfDeadPrimitive(letPrim.primitive);
     _removeNode(letPrim);
 
     // Perform bookkeeping on removed body and scan for new redexes.
     new _RemovalVisitor(_worklist).visit(letPrim.primitive);
   }
 
   /// Applies the dead-cont reduction:
   ///   letcont k x = E0 in E1 -> E1 (k not free in E1).
   void _reduceDeadCont(_ReductionTask task) {
     assert(_isDeadCont(task.node));
@@ skipping 130 matching lines @@
     // Removing an unused parameter can create an eta-redex.
     if (_isEtaCont(continuation)) {
       _worklist.add(new _ReductionTask(_ReductionKind.ETA_CONT, continuation));
     }
   }
 }
 
 /// Returns true iff the bound primitive is unused, and has no effects
 /// preventing it from being eliminated.
 bool _isDeadVal(LetPrim node) {
-  return node.primitive.hasNoUses && node.primitive.isSafeForElimination;
+  return node.primitive.hasNoEffectiveUses &&
+         node.primitive.isSafeForElimination;
 }
 
 /// Returns true iff the continuation is unused.
 bool _isDeadCont(Continuation cont) {
   return !cont.isReturnContinuation && !cont.hasAtLeastOneUse;
 }
 
 /// Returns true iff the continuation has a body (i.e., it is not the return
 /// continuation), it is used exactly once, and that use is as the continuation
 /// of a continuation invocation.
@@ skipping 268 matching lines @@
 
   String toString() => "$kind: $node";
 }
 
 /// A dummy class used solely to mark nodes as deleted once they are removed
 /// from a term.
 class _DeletedNode extends Node {
   accept(_) {}
   setParentPointers() {}
 }