Fix typo when generating a not boolified input.

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 1662 matching lines @@
       }
     }
   }
 
   visitNot(HNot node) {
     assert(node.inputs.length == 1);
     HInstruction input = node.inputs[0];
     if (input is HBoolify && isGenerateAtUseSite(input)) {
       beginExpression(JSPrecedence.EQUALITY_PRECEDENCE);
       assert(node.inputs.length == 1);
-      use(node.inputs[0], JSPrecedence.EQUALITY_PRECEDENCE);
+      use(input.inputs[0], JSPrecedence.EQUALITY_PRECEDENCE);
       buffer.add(' !== true');
       endExpression(JSPrecedence.EQUALITY_PRECEDENCE);
     } else if (input is HRelational &&
                input.builtin &&
                isGenerateAtUseSite(input)) {
       Map<String, String> inverseOperator = const <String>{
         "==" : "!=",
         "!=" : "==",
         "===": "!==",
         "!==": "===",
@@ skipping 899 matching lines @@
       startBailoutSwitch();
     }
   }
 
   void endLabeledBlock(HLabeledBlockInformation labeledBlockInfo) {
     if (labeledBlockInfo.body.start.hasGuards()) {
       endBailoutSwitch();
     }
   }
 }