Implement code generation for === and !==.

frog/leg/ssa/codegen.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 SsaCodeGeneratorTask extends CompilerTask {
   SsaCodeGeneratorTask(Compiler compiler) : super(compiler);
   String get name() => 'SSA code generator';
 
   String generate(FunctionElement function, HGraph graph) {
     return measure(() {
@@ skipping 218 matching lines @@
   visitBitOr(HBitOr node)           => visitInvokeBinary(node, '|');
   visitBitXor(HBitXor node)         => visitInvokeBinary(node, '^');
   visitShiftRight(HShiftRight node) => visitInvokeBinary(node, '>>');
 
   // Shift left cannot be mapped to the native operator (different semantics).
   visitShiftLeft(HShiftLeft node)   => visitInvokeStatic(node);
 
   visitNegate(HNegate node)         => visitInvokeUnary(node, '-');
 
   visitEquals(HEquals node)             => visitInvokeBinary(node, '===');
+  visitIdentity(HIdentity node)         => visitInvokeBinary(node, '===');
   visitLess(HLess node)                 => visitInvokeBinary(node, '<');
   visitLessEqual(HLessEqual node)       => visitInvokeBinary(node, '<=');
   visitGreater(HGreater node)           => visitInvokeBinary(node, '>');
   visitGreaterEqual(HGreaterEqual node) => visitInvokeBinary(node, '>=');
 
   visitLogicalOperator(HLogicalOperator node) {
     buffer.add("((");
     use(node.left);
     buffer.add(")${node.operation}(");
     use(node.right);
@@ skipping 608 matching lines @@
     secondBlock.last.tryGenerateAtUseSite();
   }
 
   void visitBasicBlock(HBasicBlock block) {
     if (!block.phis.isEmpty() &&
         block.phis.first == block.phis.last) {
       detectLogicControlFlow(block.phis.first);
     }
   }
 }