Remove special casing of == null

pkg/compiler/lib/src/ssa/builder_kernel.dart

 // Copyright (c) 2016, 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.
 
 import 'package:kernel/ast.dart' as ir;
 
 import '../closure.dart';
 import '../common.dart';
 import '../common/codegen.dart' show CodegenRegistry;
 import '../common/names.dart';
@@ skipping 701 matching lines @@
     close(new HGoto()).addSuccessor(block);
 
     open(block);
   }
 
   void closeFunction() {
     if (!isAborted()) closeAndGotoExit(new HGoto());
     graph.finalize();
   }
 
-  /// Pushes a boolean checking [expression] against null.
-  pushCheckNull(HInstruction expression) {
-    push(new HIdentity(expression, graph.addConstantNull(closedWorld), null,
-        commonMasks.boolType));
-  }
-
   @override
   void defaultExpression(ir.Expression expression) {
     // TODO(het): This is only to get tests working.
     _trap('Unhandled ir.${expression.runtimeType}  $expression');
   }
 
   @override
   void defaultStatement(ir.Statement statement) {
     _trap('Unhandled ir.${statement.runtimeType}  $statement');
     pop();
@@ skipping 2143 matching lines @@
   }
 
   @override
   void visitFunctionExpression(ir.FunctionExpression funcExpression) {
     funcExpression.function.accept(this);
   }
 
   // TODO(het): Decide when to inline
   @override
   void visitMethodInvocation(ir.MethodInvocation invocation) {
-    // Handle `x == null` specially. When these come from null-aware operators,
-    // there is no mapping in the astAdapter.
-    if (_handleEqualsNull(invocation)) return;
     invocation.receiver.accept(this);
     HInstruction receiver = pop();
     Selector selector = _elementMap.getSelector(invocation);
     _pushDynamicInvocation(
         invocation,
         _typeInferenceMap.typeOfInvocation(invocation, closedWorld),
         <HInstruction>[receiver]..addAll(
             _visitArgumentsForDynamicTarget(selector, invocation.arguments)));
   }
 
-  bool _handleEqualsNull(ir.MethodInvocation invocation) {
-    if (invocation.name.name == '==') {
-      ir.Arguments arguments = invocation.arguments;
-      if (arguments.types.isEmpty &&
-          arguments.positional.length == 1 &&
-          arguments.named.isEmpty) {
-        bool finish(ir.Expression comparand) {
-          comparand.accept(this);
-          pushCheckNull(pop());
-          return true;
-        }
-
-        ir.Expression receiver = invocation.receiver;
-        ir.Expression argument = arguments.positional.first;
-        if (argument is ir.NullLiteral) return finish(receiver);
-        if (receiver is ir.NullLiteral) return finish(argument);
-      }
-    }
-    return false;
-  }
-
   HInterceptor _interceptorFor(HInstruction intercepted) {
     HInterceptor interceptor =
         new HInterceptor(intercepted, commonMasks.nonNullType);
     add(interceptor);
     return interceptor;
   }
 
   static ir.Class _containingClass(ir.TreeNode node) {
     while (node != null) {
       if (node is ir.Class) return node;
@@ skipping 563 matching lines @@
     enterBlock.setBlockFlow(
         new HTryBlockInformation(
             kernelBuilder.wrapStatementGraph(bodyGraph),
             exception,
             kernelBuilder.wrapStatementGraph(catchGraph),
             kernelBuilder.wrapStatementGraph(finallyGraph)),
         exitBlock);
     kernelBuilder.inTryStatement = previouslyInTryStatement;
   }
 }