[turbofan] Minor performance tweaks in escape analysis

test/unittests/compiler/escape-analysis-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/bit-vector.h"
 #include "src/compiler/escape-analysis.h"
 #include "src/compiler/escape-analysis-reducer.h"
 #include "src/compiler/graph-visualizer.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/node-properties.h"
@@ skipping 314 matching lines @@
   ExpectVirtual(allocation);
   ExpectReplacementPhi(load, object1, object2);
   Node* replacement_phi = escape_analysis()->GetReplacement(load);
 
   Transformation();
 
   ASSERT_EQ(replacement_phi, NodeProperties::GetValueInput(result, 0));
 }
 
 
+TEST_F(EscapeAnalysisTest, BranchEscapeOne) {
+  Node* object1 = Constant(1);
+  Node* object2 = Constant(2);
+  Node* index = graph()->NewNode(common()->Parameter(0), start());
+  BeginRegion();
+  Node* allocation = Allocate(Constant(kPointerSize));
+  Store(FieldAccessAtIndex(0), allocation, object1);
+  Node* finish = FinishRegion(allocation);
+  Branch();
+  Node* ifFalse = IfFalse();
+  Node* ifTrue = IfTrue();
+  Node* effect1 =
+      Store(FieldAccessAtIndex(0), allocation, object1, finish, ifFalse);
+  Node* effect2 = StoreElement(MakeElementAccess(0), allocation, index, object2,
+                               finish, ifTrue);
+  Node* merge = Merge2(ifFalse, ifTrue);
+  Node* phi = graph()->NewNode(common()->EffectPhi(2), effect1, effect2, merge);
+  Node* load = Load(FieldAccessAtIndex(0), finish, phi, merge);
+  Node* result = Return(load, phi);
+  EndGraph();
+
+  Analysis();
+
+  ExpectEscaped(allocation);
+  ExpectReplacement(load, nullptr);
+
+  Transformation();
+
+  ASSERT_EQ(load, NodeProperties::GetValueInput(result, 0));
+}
+
+
+TEST_F(EscapeAnalysisTest, BranchEscapeThroughStore) {
+  Node* object1 = Constant(1);
+  Node* object2 = Constant(2);
+  BeginRegion();
+  Node* allocation = Allocate(Constant(kPointerSize));
+  Store(FieldAccessAtIndex(0), allocation, object1);
+  FinishRegion(allocation);
+  BeginRegion();
+  Node* allocation2 = Allocate(Constant(kPointerSize));
+  Store(FieldAccessAtIndex(0), allocation, object2);
+  Node* finish2 = FinishRegion(allocation2);
+  Branch();
+  Node* ifFalse = IfFalse();
+  Node* ifTrue = IfTrue();
+  Node* effect1 =
+      Store(FieldAccessAtIndex(0), allocation, allocation2, finish2, ifFalse);
+  Node* merge = Merge2(ifFalse, ifTrue);
+  Node* phi = graph()->NewNode(common()->EffectPhi(2), effect1, finish2, merge);
+  Node* load = Load(FieldAccessAtIndex(0), finish2, phi, merge);
+  Node* result = Return(allocation, phi);
+  EndGraph();
+  graph()->end()->AppendInput(zone(), load);
+
+  Analysis();
+
+  ExpectEscaped(allocation);
+  ExpectEscaped(allocation2);
+  ExpectReplacement(load, nullptr);
+
+  Transformation();
+
+  ASSERT_EQ(allocation, NodeProperties::GetValueInput(result, 0));
+}
+
+
 TEST_F(EscapeAnalysisTest, DanglingLoadOrder) {
   Node* object1 = Constant(1);
   Node* object2 = Constant(2);
   Node* allocation = Allocate(Constant(kPointerSize));
   Node* store1 = Store(FieldAccessAtIndex(0), allocation, object1);
   Node* load1 = Load(FieldAccessAtIndex(0), allocation);
   Node* store2 = Store(FieldAccessAtIndex(0), allocation, object2);
   Node* load2 = Load(FieldAccessAtIndex(0), allocation, store1);
   Node* result = Return(load2);
   EndGraph();
@@ skipping 91 matching lines @@
   ASSERT_EQ(object1, NodeProperties::GetValueInput(object_state, 0));
   ASSERT_EQ(object_state, NodeProperties::GetValueInput(object_state, 1));
 
   Node* object_state2 = NodeProperties::GetValueInput(state_values1, 0);
   ASSERT_EQ(object_state, object_state2);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8