Better bitwise and binary arithmetic when the left operand is known to be a number.

lib/compiler/implementation/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 1089 matching lines @@
 
     HType convertedType = new HType.fromBoundedType(type, compiler, true);
 
     // No need to convert if we know the instruction has
     // [convertedType] as a bound.
     if (original.guaranteedType == convertedType) {
       return original;
     }
 
     HInstruction instruction =
-        new HTypeConversion(convertedType, original, true);
+        new HTypeConversion.checkedModeCheck(convertedType, original);
     add(instruction);
     return instruction;
   }
 
   HGraph closeFunction() {
     // TODO(kasperl): Make this goto an implicit return.
     if (!isAborted()) close(new HGoto()).addSuccessor(graph.exit);
     graph.finalize();
     return graph;
   }
@@ skipping 2341 matching lines @@
   void visitNodeList(NodeList node) {
      node.visitChildren(this);
   }
 
   HInstruction concat(HInstruction left, HInstruction right) {
     HInstruction instruction = new HStringConcat(left, right, diagnosticNode);
     builder.add(instruction);
     return instruction;
   }
 }