Implement unlabeled continue.

dart/frog/leg/ssa/builder.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.
 
 class Interceptors {
   Compiler compiler;
   Interceptors(Compiler this.compiler);
 
   SourceString mapOperatorToMethodName(Operator op) {
     String name = op.source.stringValue;
@@ skipping 1146 matching lines @@
     });
     bodyBlock.addSuccessor(updateBlock);
     continueLocals.add(localsHandler);
 
     open(updateBlock);
 
     localsHandler = localsHandler.mergeMultiple(continueLocals, updateBlock);
 
     HLabeledBlockInformation labelInfo;
     List<LabelElement> labels = jumpHandler.labels();
+    TargetElement target = elements[loop];
     if (!labels.isEmpty()) {
       beginBodyBlock.labeledBlockInformation =
           new HLabeledBlockInformation(bodyGraph, updateBlock,
                                        jumpHandler.labels(), isContinue: true);
+    } else if (target !== null && target.isContinueTarget) {
+      beginBodyBlock.labeledBlockInformation =
+          new HLabeledBlockInformation.implicit(bodyGraph, updateBlock,
+                                                target, isContinue: true);
     }
 
     localsHandler.enterLoopUpdates(loop);
 
     update();
 
     updateBlock = close(new HGoto());
     // The back-edge completing the cycle.
     updateBlock.addSuccessor(conditionBlock);
     conditionBlock.postProcessLoopHeader();
@@ skipping 1742 matching lines @@
                                         false,
                                         <HInstruction>[target, input]));
     return builder.pop();
   }
 
   HInstruction result() {
     flushLiterals();
     return prefix;
   }
 }