Revert "Remove workaround for successors on end block from scheduler."

test/cctest/compiler/test-scheduler.cc

 // Copyright 2014 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 "test/cctest/cctest.h"
 
 #include "src/compiler/access-builder.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/generic-node-inl.h"
@@ skipping 182 matching lines @@
   BasicBlockVector* order = Scheduler::ComputeSpecialRPO(&zone_pool, &schedule);
   CheckRPONumbers(order, 1, true);
   BasicBlock* loop[] = {schedule.start()};
   CheckLoop(order, loop, 1);
 }
 
 
 TEST(RPOEntryLoop) {
   HandleAndZoneScope scope;
   Schedule schedule(scope.main_zone());
-  BasicBlock* body = schedule.NewBasicBlock();
-  schedule.AddSuccessorForTesting(schedule.start(), body);
-  schedule.AddSuccessorForTesting(body, schedule.start());
+  schedule.AddSuccessorForTesting(schedule.start(), schedule.end());
+  schedule.AddSuccessorForTesting(schedule.end(), schedule.start());
   ZonePool zone_pool(scope.main_isolate());
   BasicBlockVector* order = Scheduler::ComputeSpecialRPO(&zone_pool, &schedule);
   CheckRPONumbers(order, 2, true);
-  BasicBlock* loop[] = {schedule.start(), body};
+  BasicBlock* loop[] = {schedule.start(), schedule.end()};
   CheckLoop(order, loop, 2);
 }
 
 
 TEST(RPOEndLoop) {
   HandleAndZoneScope scope;
   Schedule schedule(scope.main_zone());
   SmartPointer<TestLoop> loop1(CreateLoop(&schedule, 2));
   schedule.AddSuccessorForTesting(schedule.start(), loop1->header());
   ZonePool zone_pool(scope.main_isolate());
@@ skipping 427 matching lines @@
 }
 
 
 TEST(RPOLoopMultibackedge) {
   HandleAndZoneScope scope;
   Schedule schedule(scope.main_zone());
 
   BasicBlock* A = schedule.start();
   BasicBlock* B = schedule.NewBasicBlock();
   BasicBlock* C = schedule.NewBasicBlock();
-  BasicBlock* D = schedule.NewBasicBlock();
+  BasicBlock* D = schedule.end();
   BasicBlock* E = schedule.NewBasicBlock();
 
   schedule.AddSuccessorForTesting(A, B);
   schedule.AddSuccessorForTesting(B, C);
   schedule.AddSuccessorForTesting(B, D);
   schedule.AddSuccessorForTesting(B, E);
   schedule.AddSuccessorForTesting(C, B);
   schedule.AddSuccessorForTesting(D, B);
   schedule.AddSuccessorForTesting(E, B);
 
@@ skipping 1343 matching lines @@
   graph.SetEnd(end);
 
   Schedule* schedule = ComputeAndVerifySchedule(6, &graph);
   BasicBlock* block = schedule->block(loop);
   CHECK_NE(NULL, loop);
   CHECK_EQ(block, schedule->block(effect));
   CHECK_GE(block->rpo_number(), 0);
 }
 
 #endif