Implement try/catch without finally, and without type checks.

frog/leg/ssa/optimize.dart

 // Copyright (c) 2011, 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 SsaOptimizerTask extends CompilerTask {
   SsaOptimizerTask(Compiler compiler) : super(compiler);
   String get name() => 'SSA optimizer';
 
   void optimize(WorkItem work, HGraph graph) {
     measure(() {
       if (!work.isBailoutVersion()) {
         // TODO(ngeoffray): We should be more fine-grained and still
         // allow type propagation of instructions we know the type.
-        new SsaTypePropagator(compiler).visitGraph(graph);
-        new SsaTypeGuardBuilder(compiler).visitGraph(graph);
-        new SsaCheckInserter(compiler).visitGraph(graph);
+        if (work.allowSpeculativeOptimization) {
+          new SsaTypePropagator(compiler).visitGraph(graph);
+          new SsaTypeGuardBuilder(compiler).visitGraph(graph);
+          new SsaCheckInserter(compiler).visitGraph(graph);
+        }
         new SsaConstantFolder(compiler).visitGraph(graph);
         new SsaRedundantPhiEliminator().visitGraph(graph);
         new SsaDeadPhiEliminator().visitGraph(graph);
         new SsaGlobalValueNumberer(compiler).visitGraph(graph);
         new SsaCodeMotion().visitGraph(graph);
         new SsaDeadCodeEliminator().visitGraph(graph);
       } else {
         new SsaBailoutBuilder(compiler, work.bailouts).visitGraph(graph);
       }
     });
@@ skipping 575 matching lines @@
         }
       }
       if (!canBeMoved) continue;
 
       // This is safe because we are running after GVN.
       // TODO(ngeoffray): ensure GVN has been run.
       set_.add(current);
     }
   }
 }