Simple sharing and hoisting of final field loads

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

 library dart2js.cps_ir_integrity;
 
 import 'cps_ir_nodes.dart';
 import 'cps_ir_nodes_sexpr.dart';
 import '../tracer.dart' as tracer;
 
 /// Dump S-expressions on error if the tracer is enabled.
 ///
 /// Technically this has nothing to do with the tracer, but if you want one
 /// enabled, you typically want the other as well, so we use the same flag.
@@ skipping 187 matching lines @@
         Decorator decorator = (n, String s) => n == node ? '**$s**' : s;
         sexpr = new SExpressionStringifier(decorator).visit(topLevelNode);
         sexpr = 'SExpr dump (offending node marked with **):\n\n$sexpr';
       } catch (e) {
         sexpr = '(Exception thrown by SExpressionStringifier: $e)';
       }
     } else {
       sexpr = '(Set DUMP_IR flag to enable SExpr dump)';
     }
     throw 'CPS integrity violation\n'
-          'After $previousPass on ${topLevelNode.element}\n'
+          'After \'$previousPass\' on ${topLevelNode.element}\n'
           '$message\n\n'
           '$sexpr\n';
   }
 }
 
 /// Traverses the CPS term and checks that node.parent is correctly set
 /// for each visited node.
 class ParentChecker extends DeepRecursiveVisitor {
   static void checkParents(Node node, CheckCpsIntegrity main) {
     ParentChecker visitor = new ParentChecker._make(main);
@@ skipping 26 matching lines @@
   }
 
   @override
   processReference(Reference node) {
     if (node.parent != _parent) {
       error('Parent pointer on $node is ${node.parent} but should be $_parent',
             node);
     }
   }
 }