Add Schedule::InsertBranch to fuse control flow graphs.

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 12 matching lines @@
   HandleAndZoneScope scope;
   Schedule schedule(scope.main_zone());
 
   CHECK_NE(NULL, schedule.start());
   CHECK_EQ(schedule.start(), schedule.GetBlockById(BasicBlock::Id::FromInt(0)));
 }
 
 
 TEST(TestScheduleAddNode) {
   HandleAndZoneScope scope;
+  Schedule schedule(scope.main_zone());
   Graph graph(scope.main_zone());
   Node* n0 = graph.NewNode(&dummy_operator);
   Node* n1 = graph.NewNode(&dummy_operator);
 
-  Schedule schedule(scope.main_zone());
-
   BasicBlock* entry = schedule.start();
   schedule.AddNode(entry, n0);
   schedule.AddNode(entry, n1);
 
   CHECK_EQ(entry, schedule.block(n0));
   CHECK_EQ(entry, schedule.block(n1));
   CHECK(schedule.SameBasicBlock(n0, n1));
 
   Node* n2 = graph.NewNode(&dummy_operator);
   CHECK_EQ(NULL, schedule.block(n2));
 }
 
 
 TEST(TestScheduleAddGoto) {
   HandleAndZoneScope scope;
+  Schedule schedule(scope.main_zone());
 
-  Schedule schedule(scope.main_zone());
   BasicBlock* entry = schedule.start();
   BasicBlock* next = schedule.NewBasicBlock();
 
   schedule.AddGoto(entry, next);
 
   CHECK_EQ(0, static_cast<int>(entry->PredecessorCount()));
   CHECK_EQ(1, static_cast<int>(entry->SuccessorCount()));
   CHECK_EQ(next, entry->SuccessorAt(0));
 
   CHECK_EQ(1, static_cast<int>(next->PredecessorCount()));
   CHECK_EQ(entry, next->PredecessorAt(0));
   CHECK_EQ(0, static_cast<int>(next->SuccessorCount()));
 }
 
 
 TEST(TestScheduleAddBranch) {
   HandleAndZoneScope scope;
   Schedule schedule(scope.main_zone());
+  Graph graph(scope.main_zone());
+  CommonOperatorBuilder common(scope.main_zone());
+  Node* n0 = graph.NewNode(&dummy_operator);
+  Node* b = graph.NewNode(common.Branch(), n0);
 
   BasicBlock* entry = schedule.start();
   BasicBlock* tblock = schedule.NewBasicBlock();
   BasicBlock* fblock = schedule.NewBasicBlock();
 
-  Graph graph(scope.main_zone());
-  CommonOperatorBuilder common(scope.main_zone());
-  Node* n0 = graph.NewNode(&dummy_operator);
-  Node* b = graph.NewNode(common.Branch(), n0);
-
   schedule.AddBranch(entry, b, tblock, fblock);
 
   CHECK_EQ(0, static_cast<int>(entry->PredecessorCount()));
   CHECK_EQ(2, static_cast<int>(entry->SuccessorCount()));
   CHECK_EQ(tblock, entry->SuccessorAt(0));
   CHECK_EQ(fblock, entry->SuccessorAt(1));
 
   CHECK_EQ(1, static_cast<int>(tblock->PredecessorCount()));
   CHECK_EQ(entry, tblock->PredecessorAt(0));
   CHECK_EQ(0, static_cast<int>(tblock->SuccessorCount()));
@@ skipping 25 matching lines @@
   Node* n0 = graph.NewNode(&dummy_operator);
   BasicBlock* entry = schedule.start();
   schedule.AddThrow(entry, n0);
 
   CHECK_EQ(0, static_cast<int>(entry->PredecessorCount()));
   CHECK_EQ(1, static_cast<int>(entry->SuccessorCount()));
   CHECK_EQ(schedule.end(), entry->SuccessorAt(0));
 }
 
 
+TEST(TestScheduleInsertBranch) {
+  HandleAndZoneScope scope;
+  Schedule schedule(scope.main_zone());
+  Graph graph(scope.main_zone());
+  CommonOperatorBuilder common(scope.main_zone());
+  Node* n0 = graph.NewNode(&dummy_operator);
+  Node* n1 = graph.NewNode(&dummy_operator);
+  Node* b = graph.NewNode(common.Branch(), n1);
+
+  BasicBlock* entry = schedule.start();
+  BasicBlock* tblock = schedule.NewBasicBlock();
+  BasicBlock* fblock = schedule.NewBasicBlock();
+  BasicBlock* merge = schedule.NewBasicBlock();
+  schedule.AddReturn(entry, n0);
+  schedule.AddGoto(tblock, merge);
+  schedule.AddGoto(fblock, merge);
+
+  schedule.InsertBranch(entry, merge, b, tblock, fblock);
+
+  CHECK_EQ(0, static_cast<int>(entry->PredecessorCount()));
+  CHECK_EQ(2, static_cast<int>(entry->SuccessorCount()));
+  CHECK_EQ(tblock, entry->SuccessorAt(0));
+  CHECK_EQ(fblock, entry->SuccessorAt(1));
+
+  CHECK_EQ(2, static_cast<int>(merge->PredecessorCount()));
+  CHECK_EQ(1, static_cast<int>(merge->SuccessorCount()));
+  CHECK_EQ(schedule.end(), merge->SuccessorAt(0));
+
+  CHECK_EQ(1, static_cast<int>(schedule.end()->PredecessorCount()));
+  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;
 
   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);
 }