[turbofan] Connect non-terminating loops via Terminate.

test/unittests/compiler/scheduler-unittest.cc

 // Copyright 2015 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/compiler/access-builder.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/graph.h"
 #include "src/compiler/graph-visualizer.h"
 #include "src/compiler/js-operator.h"
 #include "src/compiler/node.h"
@@ skipping 2449 matching lines @@
   Node* m = graph()->NewNode(common()->Merge(3), c0, c1, d);
   Node* phi = graph()->NewNode(common()->Phi(kMachInt32, 3), v0, v1, vd, m);
   Node* ret = graph()->NewNode(common()->Return(), phi, start, start);
   Node* end = graph()->NewNode(common()->End(), ret);
 
   graph()->SetEnd(end);
 
   ComputeAndVerifySchedule(16);
 }
 
+
+TARGET_TEST_F(SchedulerTest, Terminate) {
+  Node* start = graph()->NewNode(common()->Start(1));
+  graph()->SetStart(start);
+
+  Node* loop = graph()->NewNode(common()->Loop(2), start, start);
+  loop->ReplaceInput(1, loop);  // self loop, NTL.
+
+  Node* effect = graph()->NewNode(common()->EffectPhi(1), start, loop);
+
+  Node* terminate = graph()->NewNode(common()->Terminate(), effect, loop);
+  effect->ReplaceInput(1, terminate);
+
+  Node* end = graph()->NewNode(common()->End(), terminate);
+
+  graph()->SetEnd(end);
+
+  Schedule* schedule = ComputeAndVerifySchedule(6);
+  BasicBlock* block = schedule->block(loop);
+  EXPECT_EQ(block, schedule->block(effect));
+  EXPECT_GE(block->rpo_number(), 0);
+}
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8