Revert "Revert "Build new IR for functions returning a constant.""

sdk/lib/_internal/compiler/implementation/ssa/ssa.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.
 
 library ssa;
 
 import 'dart:collection';
 
 import '../closure.dart';
 import '../js/js.dart' as js;
 import '../dart2jslib.dart' hide Selector, TypedSelector;
 import '../dart_types.dart';
 import '../source_file.dart';
 import '../source_map_builder.dart';
 import '../elements/elements.dart';
 import '../js_backend/js_backend.dart';
 import '../native_handler.dart' as native;
 import '../tree/tree.dart';
+import '../ir/ir_nodes.dart';
 import '../types/types.dart';
 import '../universe/universe.dart';
 import '../util/util.dart';
 
 import '../scanner/scannerlib.dart'
     show PartialFunctionElement, Token, PLUS_TOKEN;
 
 import '../elements/modelx.dart'
     show ElementX,
          ConstructorBodyElementX;
 
 import '../js_emitter/js_emitter.dart' show CodeEmitterTask;
 
 part 'builder.dart';
+part 'from_ir_builder.dart';
+part 'from_ir_inliner.dart';
 part 'codegen.dart';
 part 'codegen_helpers.dart';
 part 'interceptor_simplifier.dart';
 part 'invoke_dynamic_specializers.dart';
 part 'nodes.dart';
 part 'optimize.dart';
 part 'types.dart';
 part 'types_propagation.dart';
 part 'validate.dart';
 part 'variable_allocator.dart';
 part 'value_range_analyzer.dart';
 part 'value_set.dart';