Fix bad precedence for >>> operator.

lib/compiler/implementation/ssa/codegen.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 SsaCodeGeneratorTask extends CompilerTask {
   SsaCodeGeneratorTask(Compiler compiler) : super(compiler);
   String get name() => 'SSA code generator';
 
 
   String buildJavaScriptFunction(FunctionElement element,
@@ skipping 1103 matching lines @@
     } else {
       visitInvokeStatic(node);
     }
   }
 
   // We want the outcome of bit-operations to be positive. We use the unsigned
   // shift operator to achieve this.
   visitBitInvokeBinary(HBinaryBitOp node, String op) {
     if (node.builtin){
       beginExpression(unsignedShiftPrecedences.precedence);
+      int oldPrecedence = this.expectedPrecedence;
+      this.expectedPrecedence = JSPrecedence.SHIFT_PRECEDENCE;
       visitInvokeBinary(node, op);
       buffer.add(' >>> 0');
+      this.expectedPrecedence = oldPrecedence;
       endExpression(unsignedShiftPrecedences.precedence);
     } else {
       visitInvokeBinary(node, op);
     }
   }
 
   visitInvokeUnary(HInvokeUnary node, String op) {
     if (node.builtin) {
       beginExpression(JSPrecedence.PREFIX_PRECEDENCE);
       buffer.add('$op');
       use(node.operand, JSPrecedence.PREFIX_PRECEDENCE);
       endExpression(JSPrecedence.PREFIX_PRECEDENCE);
     } else {
       visitInvokeStatic(node);
     }
   }
 
   // We want the outcome of bit-operations to be positive. We use the unsigned
   // shift operator to achieve this.
   visitBitInvokeUnary(HInvokeUnary node, String op) {
     if (node.builtin){
       beginExpression(unsignedShiftPrecedences.precedence);
+      int oldPrecedence = this.expectedPrecedence;
+      this.expectedPrecedence = JSPrecedence.SHIFT_PRECEDENCE;
       visitInvokeUnary(node, op);
       buffer.add(' >>> 0');
+      this.expectedPrecedence = oldPrecedence;
       endExpression(unsignedShiftPrecedences.precedence);
     } else {
       visitInvokeUnary(node, op);
     }
   }
 
   visitEquals(HEquals node) {
     if (node.builtin) {
       beginExpression(JSPrecedence.EQUALITY_PRECEDENCE);
       use(node.left, JSPrecedence.EQUALITY_PRECEDENCE);
@@ skipping 1327 matching lines @@
       startBailoutSwitch();
     }
   }
 
   void endLabeledBlock(HLabeledBlockInformation labeledBlockInfo) {
     if (labeledBlockInfo.body.start.hasGuards()) {
       endBailoutSwitch();
     }
   }
 }