Fix bugs in simplified lowering relating to int32/uint32 signs.

test/cctest/compiler/test-schedule.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #include "src/compiler/common-operator.h"
 #include "src/compiler/generic-node-inl.h"
 #include "src/compiler/graph.h"
 #include "src/compiler/machine-operator.h"
@@ skipping 145 matching lines @@
   CHECK_EQ(0, static_cast<int>(schedule.end()->SuccessorCount()));
   CHECK_EQ(merge, schedule.end()->PredecessorAt(0));
 }
 
 
 TEST(BuildMulNodeGraph) {
   HandleAndZoneScope scope;
   Schedule schedule(scope.main_zone());
   Graph graph(scope.main_zone());
   CommonOperatorBuilder common(scope.main_zone());
-  MachineOperatorBuilder machine;
+  // TODO(titzer): use test operators.
+  MachineOperatorBuilder machine(scope.main_zone());
 
   Node* start = graph.NewNode(common.Start(0));
   graph.SetStart(start);
   Node* param0 = graph.NewNode(common.Parameter(0), graph.start());
   Node* param1 = graph.NewNode(common.Parameter(1), graph.start());
 
   Node* mul = graph.NewNode(machine.Int32Mul(), param0, param1);
   Node* ret = graph.NewNode(common.Return(), mul, start);
 
   USE(ret);
 }