Land the Fan (disabled)

test/cctest/compiler/test-node.cc

Index: test/cctest/compiler/test-node.cc
diff --git a/test/cctest/compiler/test-node.cc b/test/cctest/compiler/test-node.cc
new file mode 100644
index 0000000000000000000000000000000000000000..541175506b42b1b3daba20071e7952107f3ed03a
--- /dev/null
+++ b/test/cctest/compiler/test-node.cc
@@ -0,0 +1,813 @@
+// 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 "graph-tester.h"
+#include "src/compiler/generic-node-inl.h"
+#include "src/compiler/node.h"
+#include "src/compiler/operator.h"
+
+using namespace v8::internal;
+using namespace v8::internal::compiler;
+
+static SimpleOperator dummy_operator(IrOpcode::kParameter, Operator::kNoWrite,
+                                     0, 0, "dummy");
+
+TEST(NodeAllocation) {
+  GraphTester graph;
+  Node* n1 = graph.NewNode(&dummy_operator);
+  Node* n2 = graph.NewNode(&dummy_operator);
+  CHECK(n2->id() != n1->id());
+}
+
+
+TEST(NodeWithOpcode) {
+  GraphTester graph;
+  Node* n1 = graph.NewNode(&dummy_operator);
+  Node* n2 = graph.NewNode(&dummy_operator);
+  CHECK(n1->op() == &dummy_operator);
+  CHECK(n2->op() == &dummy_operator);
+}
+
+
+TEST(NodeInputs1) {
+  GraphTester graph;
+  Node* n0 = graph.NewNode(&dummy_operator);
+  Node* n2 = graph.NewNode(&dummy_operator, n0);
+  CHECK_EQ(1, n2->InputCount());
+  CHECK(n0 == n2->InputAt(0));
+}
+
+
+TEST(NodeInputs2) {
+  GraphTester graph;
+  Node* n0 = graph.NewNode(&dummy_operator);
+  Node* n1 = graph.NewNode(&dummy_operator);
+  Node* n2 = graph.NewNode(&dummy_operator, n0, n1);
+  CHECK_EQ(2, n2->InputCount());
+  CHECK(n0 == n2->InputAt(0));
+  CHECK(n1 == n2->InputAt(1));
+}
+
+
+TEST(NodeInputs3) {
+  GraphTester graph;
+  Node* n0 = graph.NewNode(&dummy_operator);
+  Node* n1 = graph.NewNode(&dummy_operator);
+  Node* n2 = graph.NewNode(&dummy_operator, n0, n1, n1);
+  CHECK_EQ(3, n2->InputCount());
+  CHECK(n0 == n2->InputAt(0));
+  CHECK(n1 == n2->InputAt(1));
+  CHECK(n1 == n2->InputAt(2));
+}
+
+
+TEST(NodeInputIteratorEmpty) {
+  GraphTester graph;
+  Node* n1 = graph.NewNode(&dummy_operator);
+  Node::Inputs::iterator i(n1->inputs().begin());
+  int input_count = 0;
+  for (; i != n1->inputs().end(); ++i) {
+    input_count++;
+  }
+  CHECK_EQ(0, input_count);
+}
+
+
+TEST(NodeInputIteratorOne) {
+  GraphTester graph;
+  Node* n0 = graph.NewNode(&dummy_operator);
+  Node* n1 = graph.NewNode(&dummy_operator, n0);
+  Node::Inputs::iterator i(n1->inputs().begin());
+  CHECK_EQ(1, n1->InputCount());
+  CHECK_EQ(n0, *i);
+  ++i;
+  CHECK(n1->inputs().end() == i);
+}
+
+
+TEST(NodeUseIteratorEmpty) {
+  GraphTester graph;
+  Node* n1 = graph.NewNode(&dummy_operator);
+  Node::Uses::iterator i(n1->uses().begin());
+  int use_count = 0;
+  for (; i != n1->uses().end(); ++i) {
+    Node::Edge edge(i.edge());
+    USE(edge);
+    use_count++;
+  }
+  CHECK_EQ(0, use_count);
+}
+
+
+TEST(NodeUseIteratorOne) {
+  GraphTester graph;
+  Node* n0 = graph.NewNode(&dummy_operator);
+  Node* n1 = graph.NewNode(&dummy_operator, n0);
+  Node::Uses::iterator i(n0->uses().begin());
+  CHECK_EQ(n1, *i);
+  ++i;
+  CHECK(n0->uses().end() == i);
+}
+
+
+TEST(NodeUseIteratorReplaceNoUses) {
+  GraphTester graph;
+  Node* n0 = graph.NewNode(&dummy_operator);
+  Node* n3 = graph.NewNode(&dummy_operator);
+  n0->ReplaceUses(n3);
+  CHECK(n0->uses().begin() == n0->uses().end());
+}
+
+
+TEST(NodeUseIteratorReplaceUses) {
+  GraphTester graph;
+  Node* n0 = graph.NewNode(&dummy_operator);
+  Node* n1 = graph.NewNode(&dummy_operator, n0);
+  Node* n2 = graph.NewNode(&dummy_operator, n0);
+  Node* n3 = graph.NewNode(&dummy_operator);
+  Node::Uses::iterator i1(n0->uses().begin());
+  CHECK_EQ(n1, *i1);
+  ++i1;
+  CHECK_EQ(n2, *i1);
+  n0->ReplaceUses(n3);
+  Node::Uses::iterator i2(n3->uses().begin());
+  CHECK_EQ(n1, *i2);
+  ++i2;
+  CHECK_EQ(n2, *i2);
+  Node::Inputs::iterator i3(n1->inputs().begin());
+  CHECK_EQ(n3, *i3);
+  ++i3;
+  CHECK(n1->inputs().end() == i3);
+  Node::Inputs::iterator i4(n2->inputs().begin());
+  CHECK_EQ(n3, *i4);
+  ++i4;
+  CHECK(n2->inputs().end() == i4);
+}
+
+
+TEST(NodeUseIteratorReplaceUsesSelf) {
+  GraphTester graph;
+  Node* n0 = graph.NewNode(&dummy_operator);
+  Node* n1 = graph.NewNode(&dummy_operator, n0);
+  Node* n3 = graph.NewNode(&dummy_operator);
+
+  n1->ReplaceInput(0, n1);  // Create self-reference.
+
+  Node::Uses::iterator i1(n1->uses().begin());
+  CHECK_EQ(n1, *i1);
+
+  n1->ReplaceUses(n3);
+
+  CHECK(n1->uses().begin() == n1->uses().end());
+
+  Node::Uses::iterator i2(n3->uses().begin());
+  CHECK_EQ(n1, *i2);
+  ++i2;
+  CHECK(n1->uses().end() == i2);
+}
+
+
+TEST(ReplaceInput) {
+  GraphTester graph;
+  Node* n0 = graph.NewNode(&dummy_operator);
+  Node* n1 = graph.NewNode(&dummy_operator);
+  Node* n2 = graph.NewNode(&dummy_operator);
+  Node* n3 = graph.NewNode(&dummy_operator, n0, n1, n2);
+  Node::Inputs::iterator i1(n3->inputs().begin());
+  CHECK(n0 == *i1);
+  CHECK_EQ(n0, n3->InputAt(0));
+  ++i1;
+  CHECK_EQ(n1, *i1);
+  CHECK_EQ(n1, n3->InputAt(1));
+  ++i1;
+  CHECK_EQ(n2, *i1);
+  CHECK_EQ(n2, n3->InputAt(2));
+  ++i1;
+  CHECK(i1 == n3->inputs().end());
+
+  Node::Uses::iterator i2(n1->uses().begin());
+  CHECK_EQ(n3, *i2);
+  ++i2;
+  CHECK(i2 == n1->uses().end());
+
+  Node* n4 = graph.NewNode(&dummy_operator);
+  Node::Uses::iterator i3(n4->uses().begin());
+  CHECK(i3 == n4->uses().end());
+
+  n3->ReplaceInput(1, n4);
+
+  Node::Uses::iterator i4(n1->uses().begin());
+  CHECK(i4 == n1->uses().end());
+
+  Node::Uses::iterator i5(n4->uses().begin());
+  CHECK_EQ(n3, *i5);
+  ++i5;
+  CHECK(i5 == n4->uses().end());
+
+  Node::Inputs::iterator i6(n3->inputs().begin());
+  CHECK(n0 == *i6);
+  CHECK_EQ(n0, n3->InputAt(0));
+  ++i6;
+  CHECK_EQ(n4, *i6);
+  CHECK_EQ(n4, n3->InputAt(1));
+  ++i6;
+  CHECK_EQ(n2, *i6);
+  CHECK_EQ(n2, n3->InputAt(2));
+  ++i6;
+  CHECK(i6 == n3->inputs().end());
+}
+
+
+TEST(OwnedBy) {
+  GraphTester graph;
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n1 = graph.NewNode(&dummy_operator);
+
+    CHECK(!n0->OwnedBy(n1));
+    CHECK(!n1->OwnedBy(n0));
+
+    Node* n2 = graph.NewNode(&dummy_operator, n0);
+    CHECK(n0->OwnedBy(n2));
+    CHECK(!n2->OwnedBy(n0));
+
+    Node* n3 = graph.NewNode(&dummy_operator, n0);
+    CHECK(!n0->OwnedBy(n2));
+    CHECK(!n0->OwnedBy(n3));
+    CHECK(!n2->OwnedBy(n0));
+    CHECK(!n3->OwnedBy(n0));
+  }
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n1 = graph.NewNode(&dummy_operator, n0);
+    CHECK(n0->OwnedBy(n1));
+    CHECK(!n1->OwnedBy(n0));
+    Node* n2 = graph.NewNode(&dummy_operator, n0);
+    CHECK(!n0->OwnedBy(n1));
+    CHECK(!n0->OwnedBy(n2));
+    CHECK(!n1->OwnedBy(n0));
+    CHECK(!n1->OwnedBy(n2));
+    CHECK(!n2->OwnedBy(n0));
+    CHECK(!n2->OwnedBy(n1));
+
+    Node* n3 = graph.NewNode(&dummy_operator);
+    n2->ReplaceInput(0, n3);
+
+    CHECK(n0->OwnedBy(n1));
+    CHECK(!n1->OwnedBy(n0));
+    CHECK(!n1->OwnedBy(n0));
+    CHECK(!n1->OwnedBy(n2));
+    CHECK(!n2->OwnedBy(n0));
+    CHECK(!n2->OwnedBy(n1));
+    CHECK(n3->OwnedBy(n2));
+    CHECK(!n2->OwnedBy(n3));
+  }
+}
+
+
+TEST(Uses) {
+  GraphTester graph;
+
+  Node* n0 = graph.NewNode(&dummy_operator);
+  Node* n1 = graph.NewNode(&dummy_operator, n0);
+  CHECK_EQ(1, n0->UseCount());
+  printf("A: %d vs %d\n", n0->UseAt(0)->id(), n1->id());
+  CHECK(n0->UseAt(0) == n1);
+  Node* n2 = graph.NewNode(&dummy_operator, n0);
+  CHECK_EQ(2, n0->UseCount());
+  printf("B: %d vs %d\n", n0->UseAt(1)->id(), n2->id());
+  CHECK(n0->UseAt(1) == n2);
+  Node* n3 = graph.NewNode(&dummy_operator, n0);
+  CHECK_EQ(3, n0->UseCount());
+  CHECK(n0->UseAt(2) == n3);
+}
+
+
+TEST(Inputs) {
+  GraphTester graph;
+
+  Node* n0 = graph.NewNode(&dummy_operator);
+  Node* n1 = graph.NewNode(&dummy_operator, n0);
+  Node* n2 = graph.NewNode(&dummy_operator, n0);
+  Node* n3 = graph.NewNode(&dummy_operator, n0, n1, n2);
+  CHECK_EQ(3, n3->InputCount());
+  CHECK(n3->InputAt(0) == n0);
+  CHECK(n3->InputAt(1) == n1);
+  CHECK(n3->InputAt(2) == n2);
+  Node* n4 = graph.NewNode(&dummy_operator, n0, n1, n2);
+  n3->AppendInput(graph.zone(), n4);
+  CHECK_EQ(4, n3->InputCount());
+  CHECK(n3->InputAt(0) == n0);
+  CHECK(n3->InputAt(1) == n1);
+  CHECK(n3->InputAt(2) == n2);
+  CHECK(n3->InputAt(3) == n4);
+  Node* n5 = graph.NewNode(&dummy_operator, n4);
+  n3->AppendInput(graph.zone(), n4);
+  CHECK_EQ(5, n3->InputCount());
+  CHECK(n3->InputAt(0) == n0);
+  CHECK(n3->InputAt(1) == n1);
+  CHECK(n3->InputAt(2) == n2);
+  CHECK(n3->InputAt(3) == n4);
+  CHECK(n3->InputAt(4) == n4);
+
+  // Make sure uses have been hooked op correctly.
+  Node::Uses uses(n4->uses());
+  Node::Uses::iterator current = uses.begin();
+  CHECK(current != uses.end());
+  CHECK(*current == n3);
+  ++current;
+  CHECK(current != uses.end());
+  CHECK(*current == n5);
+  ++current;
+  CHECK(current != uses.end());
+  CHECK(*current == n3);
+  ++current;
+  CHECK(current == uses.end());
+}
+
+
+TEST(AppendInputsAndIterator) {
+  GraphTester graph;
+
+  Node* n0 = graph.NewNode(&dummy_operator);
+  Node* n1 = graph.NewNode(&dummy_operator, n0);
+  Node* n2 = graph.NewNode(&dummy_operator, n0, n1);
+
+  Node::Inputs inputs(n2->inputs());
+  Node::Inputs::iterator current = inputs.begin();
+  CHECK(current != inputs.end());
+  CHECK(*current == n0);
+  ++current;
+  CHECK(current != inputs.end());
+  CHECK(*current == n1);
+  ++current;
+  CHECK(current == inputs.end());
+
+  Node* n3 = graph.NewNode(&dummy_operator);
+  n2->AppendInput(graph.zone(), n3);
+  inputs = n2->inputs();
+  current = inputs.begin();
+  CHECK(current != inputs.end());
+  CHECK(*current == n0);
+  CHECK_EQ(0, current.index());
+  ++current;
+  CHECK(current != inputs.end());
+  CHECK(*current == n1);
+  CHECK_EQ(1, current.index());
+  ++current;
+  CHECK(current != inputs.end());
+  CHECK(*current == n3);
+  CHECK_EQ(2, current.index());
+  ++current;
+  CHECK(current == inputs.end());
+}
+
+
+TEST(NullInputsSimple) {
+  GraphTester graph;
+
+  Node* n0 = graph.NewNode(&dummy_operator);
+  Node* n1 = graph.NewNode(&dummy_operator, n0);
+  Node* n2 = graph.NewNode(&dummy_operator, n0, n1);
+  CHECK_EQ(2, n2->InputCount());
+
+  CHECK(n0 == n2->InputAt(0));
+  CHECK(n1 == n2->InputAt(1));
+  CHECK_EQ(2, n0->UseCount());
+  n2->ReplaceInput(0, NULL);
+  CHECK(NULL == n2->InputAt(0));
+  CHECK(n1 == n2->InputAt(1));
+  CHECK_EQ(1, n0->UseCount());
+}
+
+
+TEST(NullInputsAppended) {
+  GraphTester graph;
+
+  Node* n0 = graph.NewNode(&dummy_operator);
+  Node* n1 = graph.NewNode(&dummy_operator, n0);
+  Node* n2 = graph.NewNode(&dummy_operator, n0);
+  Node* n3 = graph.NewNode(&dummy_operator, n0);
+  n3->AppendInput(graph.zone(), n1);
+  n3->AppendInput(graph.zone(), n2);
+  CHECK_EQ(3, n3->InputCount());
+
+  CHECK(n0 == n3->InputAt(0));
+  CHECK(n1 == n3->InputAt(1));
+  CHECK(n2 == n3->InputAt(2));
+  CHECK_EQ(1, n1->UseCount());
+  n3->ReplaceInput(1, NULL);
+  CHECK(n0 == n3->InputAt(0));
+  CHECK(NULL == n3->InputAt(1));
+  CHECK(n2 == n3->InputAt(2));
+  CHECK_EQ(0, n1->UseCount());
+}
+
+
+TEST(ReplaceUsesFromAppendedInputs) {
+  GraphTester graph;
+
+  Node* n0 = graph.NewNode(&dummy_operator);
+  Node* n1 = graph.NewNode(&dummy_operator, n0);
+  Node* n2 = graph.NewNode(&dummy_operator, n0);
+  Node* n3 = graph.NewNode(&dummy_operator);
+  n2->AppendInput(graph.zone(), n1);
+  n2->AppendInput(graph.zone(), n0);
+  CHECK_EQ(0, n3->UseCount());
+  CHECK_EQ(3, n0->UseCount());
+  n0->ReplaceUses(n3);
+  CHECK_EQ(0, n0->UseCount());
+  CHECK_EQ(3, n3->UseCount());
+
+  Node::Uses uses(n3->uses());
+  Node::Uses::iterator current = uses.begin();
+  CHECK(current != uses.end());
+  CHECK(*current == n1);
+  ++current;
+  CHECK(current != uses.end());
+  CHECK(*current == n2);
+  ++current;
+  CHECK(current != uses.end());
+  CHECK(*current == n2);
+  ++current;
+  CHECK(current == uses.end());
+}
+
+
+template <bool result>
+struct FixedPredicate {
+  bool operator()(const Node* node) const { return result; }
+};
+
+
+TEST(ReplaceUsesIfWithFixedPredicate) {
+  GraphTester graph;
+
+  Node* n0 = graph.NewNode(&dummy_operator);
+  Node* n1 = graph.NewNode(&dummy_operator, n0);
+  Node* n2 = graph.NewNode(&dummy_operator, n0);
+  Node* n3 = graph.NewNode(&dummy_operator);
+
+  CHECK_EQ(0, n2->UseCount());
+  n2->ReplaceUsesIf(FixedPredicate<true>(), n1);
+  CHECK_EQ(0, n2->UseCount());
+  n2->ReplaceUsesIf(FixedPredicate<false>(), n1);
+  CHECK_EQ(0, n2->UseCount());
+
+  CHECK_EQ(0, n3->UseCount());
+  n3->ReplaceUsesIf(FixedPredicate<true>(), n1);
+  CHECK_EQ(0, n3->UseCount());
+  n3->ReplaceUsesIf(FixedPredicate<false>(), n1);
+  CHECK_EQ(0, n3->UseCount());
+
+  CHECK_EQ(2, n0->UseCount());
+  CHECK_EQ(0, n1->UseCount());
+  n0->ReplaceUsesIf(FixedPredicate<false>(), n1);
+  CHECK_EQ(2, n0->UseCount());
+  CHECK_EQ(0, n1->UseCount());
+  n0->ReplaceUsesIf(FixedPredicate<true>(), n1);
+  CHECK_EQ(0, n0->UseCount());
+  CHECK_EQ(2, n1->UseCount());
+
+  n1->AppendInput(graph.zone(), n1);
+  CHECK_EQ(3, n1->UseCount());
+  n1->AppendInput(graph.zone(), n3);
+  CHECK_EQ(1, n3->UseCount());
+  n3->ReplaceUsesIf(FixedPredicate<true>(), n1);
+  CHECK_EQ(4, n1->UseCount());
+  CHECK_EQ(0, n3->UseCount());
+  n1->ReplaceUsesIf(FixedPredicate<false>(), n3);
+  CHECK_EQ(4, n1->UseCount());
+  CHECK_EQ(0, n3->UseCount());
+}
+
+
+TEST(ReplaceUsesIfWithEqualTo) {
+  GraphTester graph;
+
+  Node* n0 = graph.NewNode(&dummy_operator);
+  Node* n1 = graph.NewNode(&dummy_operator, n0);
+  Node* n2 = graph.NewNode(&dummy_operator, n0, n1);
+
+  CHECK_EQ(0, n2->UseCount());
+  n2->ReplaceUsesIf(std::bind1st(std::equal_to<Node*>(), n1), n0);
+  CHECK_EQ(0, n2->UseCount());
+
+  CHECK_EQ(2, n0->UseCount());
+  CHECK_EQ(1, n1->UseCount());
+  n1->ReplaceUsesIf(std::bind1st(std::equal_to<Node*>(), n0), n0);
+  CHECK_EQ(2, n0->UseCount());
+  CHECK_EQ(1, n1->UseCount());
+  n0->ReplaceUsesIf(std::bind2nd(std::equal_to<Node*>(), n2), n1);
+  CHECK_EQ(1, n0->UseCount());
+  CHECK_EQ(2, n1->UseCount());
+}
+
+
+TEST(ReplaceInputMultipleUses) {
+  GraphTester graph;
+
+  Node* n0 = graph.NewNode(&dummy_operator);
+  Node* n1 = graph.NewNode(&dummy_operator);
+  Node* n2 = graph.NewNode(&dummy_operator, n0);
+  n2->ReplaceInput(0, n1);
+  CHECK_EQ(0, n0->UseCount());
+  CHECK_EQ(1, n1->UseCount());
+
+  Node* n3 = graph.NewNode(&dummy_operator, n0);
+  n3->ReplaceInput(0, n1);
+  CHECK_EQ(0, n0->UseCount());
+  CHECK_EQ(2, n1->UseCount());
+}
+
+
+TEST(TrimInputCountInline) {
+  GraphTester graph;
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n1 = graph.NewNode(&dummy_operator, n0);
+    n1->TrimInputCount(1);
+    CHECK_EQ(1, n1->InputCount());
+    CHECK_EQ(n0, n1->InputAt(0));
+    CHECK_EQ(1, n0->UseCount());
+  }
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n1 = graph.NewNode(&dummy_operator, n0);
+    n1->TrimInputCount(0);
+    CHECK_EQ(0, n1->InputCount());
+    CHECK_EQ(0, n0->UseCount());
+  }
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n1 = graph.NewNode(&dummy_operator);
+    Node* n2 = graph.NewNode(&dummy_operator, n0, n1);
+    n2->TrimInputCount(2);
+    CHECK_EQ(2, n2->InputCount());
+    CHECK_EQ(1, n0->UseCount());
+    CHECK_EQ(1, n1->UseCount());
+    CHECK_EQ(0, n2->UseCount());
+  }
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n1 = graph.NewNode(&dummy_operator);
+    Node* n2 = graph.NewNode(&dummy_operator, n0, n1);
+    n2->TrimInputCount(1);
+    CHECK_EQ(1, n2->InputCount());
+    CHECK_EQ(1, n0->UseCount());
+    CHECK_EQ(0, n1->UseCount());
+    CHECK_EQ(0, n2->UseCount());
+  }
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n1 = graph.NewNode(&dummy_operator);
+    Node* n2 = graph.NewNode(&dummy_operator, n0, n1);
+    n2->TrimInputCount(0);
+    CHECK_EQ(0, n2->InputCount());
+    CHECK_EQ(0, n0->UseCount());
+    CHECK_EQ(0, n1->UseCount());
+    CHECK_EQ(0, n2->UseCount());
+  }
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n2 = graph.NewNode(&dummy_operator, n0, n0);
+    n2->TrimInputCount(1);
+    CHECK_EQ(1, n2->InputCount());
+    CHECK_EQ(1, n0->UseCount());
+    CHECK_EQ(0, n2->UseCount());
+  }
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n2 = graph.NewNode(&dummy_operator, n0, n0);
+    n2->TrimInputCount(0);
+    CHECK_EQ(0, n2->InputCount());
+    CHECK_EQ(0, n0->UseCount());
+    CHECK_EQ(0, n2->UseCount());
+  }
+}
+
+
+TEST(TrimInputCountOutOfLine1) {
+  GraphTester graph;
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n1 = graph.NewNode(&dummy_operator);
+    n1->AppendInput(graph.zone(), n0);
+    n1->TrimInputCount(1);
+    CHECK_EQ(1, n1->InputCount());
+    CHECK_EQ(n0, n1->InputAt(0));
+    CHECK_EQ(1, n0->UseCount());
+  }
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n1 = graph.NewNode(&dummy_operator);
+    n1->AppendInput(graph.zone(), n0);
+    CHECK_EQ(1, n1->InputCount());
+    n1->TrimInputCount(0);
+    CHECK_EQ(0, n1->InputCount());
+    CHECK_EQ(0, n0->UseCount());
+  }
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n1 = graph.NewNode(&dummy_operator);
+    Node* n2 = graph.NewNode(&dummy_operator);
+    n2->AppendInput(graph.zone(), n0);
+    n2->AppendInput(graph.zone(), n1);
+    CHECK_EQ(2, n2->InputCount());
+    n2->TrimInputCount(2);
+    CHECK_EQ(2, n2->InputCount());
+    CHECK_EQ(n0, n2->InputAt(0));
+    CHECK_EQ(n1, n2->InputAt(1));
+    CHECK_EQ(1, n0->UseCount());
+    CHECK_EQ(1, n1->UseCount());
+    CHECK_EQ(0, n2->UseCount());
+  }
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n1 = graph.NewNode(&dummy_operator);
+    Node* n2 = graph.NewNode(&dummy_operator);
+    n2->AppendInput(graph.zone(), n0);
+    n2->AppendInput(graph.zone(), n1);
+    CHECK_EQ(2, n2->InputCount());
+    n2->TrimInputCount(1);
+    CHECK_EQ(1, n2->InputCount());
+    CHECK_EQ(n0, n2->InputAt(0));
+    CHECK_EQ(1, n0->UseCount());
+    CHECK_EQ(0, n1->UseCount());
+    CHECK_EQ(0, n2->UseCount());
+  }
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n1 = graph.NewNode(&dummy_operator);
+    Node* n2 = graph.NewNode(&dummy_operator);
+    n2->AppendInput(graph.zone(), n0);
+    n2->AppendInput(graph.zone(), n1);
+    CHECK_EQ(2, n2->InputCount());
+    n2->TrimInputCount(0);
+    CHECK_EQ(0, n2->InputCount());
+    CHECK_EQ(0, n0->UseCount());
+    CHECK_EQ(0, n1->UseCount());
+    CHECK_EQ(0, n2->UseCount());
+  }
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n2 = graph.NewNode(&dummy_operator);
+    n2->AppendInput(graph.zone(), n0);
+    n2->AppendInput(graph.zone(), n0);
+    CHECK_EQ(2, n2->InputCount());
+    CHECK_EQ(2, n0->UseCount());
+    n2->TrimInputCount(1);
+    CHECK_EQ(1, n2->InputCount());
+    CHECK_EQ(1, n0->UseCount());
+    CHECK_EQ(0, n2->UseCount());
+  }
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n2 = graph.NewNode(&dummy_operator);
+    n2->AppendInput(graph.zone(), n0);
+    n2->AppendInput(graph.zone(), n0);
+    CHECK_EQ(2, n2->InputCount());
+    CHECK_EQ(2, n0->UseCount());
+    n2->TrimInputCount(0);
+    CHECK_EQ(0, n2->InputCount());
+    CHECK_EQ(0, n0->UseCount());
+    CHECK_EQ(0, n2->UseCount());
+  }
+}
+
+
+TEST(TrimInputCountOutOfLine2) {
+  GraphTester graph;
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n1 = graph.NewNode(&dummy_operator);
+    Node* n2 = graph.NewNode(&dummy_operator, n0);
+    n2->AppendInput(graph.zone(), n1);
+    CHECK_EQ(2, n2->InputCount());
+    n2->TrimInputCount(2);
+    CHECK_EQ(2, n2->InputCount());
+    CHECK_EQ(n0, n2->InputAt(0));
+    CHECK_EQ(n1, n2->InputAt(1));
+    CHECK_EQ(1, n0->UseCount());
+    CHECK_EQ(1, n1->UseCount());
+    CHECK_EQ(0, n2->UseCount());
+  }
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n1 = graph.NewNode(&dummy_operator);
+    Node* n2 = graph.NewNode(&dummy_operator, n0);
+    n2->AppendInput(graph.zone(), n1);
+    CHECK_EQ(2, n2->InputCount());
+    n2->TrimInputCount(1);
+    CHECK_EQ(1, n2->InputCount());
+    CHECK_EQ(n0, n2->InputAt(0));
+    CHECK_EQ(1, n0->UseCount());
+    CHECK_EQ(0, n1->UseCount());
+    CHECK_EQ(0, n2->UseCount());
+  }
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n1 = graph.NewNode(&dummy_operator);
+    Node* n2 = graph.NewNode(&dummy_operator, n0);
+    n2->AppendInput(graph.zone(), n1);
+    CHECK_EQ(2, n2->InputCount());
+    n2->TrimInputCount(0);
+    CHECK_EQ(0, n2->InputCount());
+    CHECK_EQ(0, n0->UseCount());
+    CHECK_EQ(0, n1->UseCount());
+    CHECK_EQ(0, n2->UseCount());
+  }
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n2 = graph.NewNode(&dummy_operator, n0);
+    n2->AppendInput(graph.zone(), n0);
+    CHECK_EQ(2, n2->InputCount());
+    CHECK_EQ(2, n0->UseCount());
+    n2->TrimInputCount(1);
+    CHECK_EQ(1, n2->InputCount());
+    CHECK_EQ(1, n0->UseCount());
+    CHECK_EQ(0, n2->UseCount());
+  }
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n2 = graph.NewNode(&dummy_operator, n0);
+    n2->AppendInput(graph.zone(), n0);
+    CHECK_EQ(2, n2->InputCount());
+    CHECK_EQ(2, n0->UseCount());
+    n2->TrimInputCount(0);
+    CHECK_EQ(0, n2->InputCount());
+    CHECK_EQ(0, n0->UseCount());
+    CHECK_EQ(0, n2->UseCount());
+  }
+}
+
+
+TEST(RemoveAllInputs) {
+  GraphTester graph;
+
+  for (int i = 0; i < 2; i++) {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n1 = graph.NewNode(&dummy_operator, n0);
+    Node* n2;
+    if (i == 0) {
+      n2 = graph.NewNode(&dummy_operator, n0, n1);
+    } else {
+      n2 = graph.NewNode(&dummy_operator, n0);
+      n2->AppendInput(graph.zone(), n1);  // with out-of-line input.
+    }
+
+    n0->RemoveAllInputs();
+    CHECK_EQ(0, n0->InputCount());
+
+    CHECK_EQ(2, n0->UseCount());
+    n1->RemoveAllInputs();
+    CHECK_EQ(1, n1->InputCount());
+    CHECK_EQ(1, n0->UseCount());
+    CHECK_EQ(NULL, n1->InputAt(0));
+
+    CHECK_EQ(1, n1->UseCount());
+    n2->RemoveAllInputs();
+    CHECK_EQ(2, n2->InputCount());
+    CHECK_EQ(0, n0->UseCount());
+    CHECK_EQ(0, n1->UseCount());
+    CHECK_EQ(NULL, n2->InputAt(0));
+    CHECK_EQ(NULL, n2->InputAt(1));
+  }
+
+  {
+    Node* n0 = graph.NewNode(&dummy_operator);
+    Node* n1 = graph.NewNode(&dummy_operator, n0);
+    n1->ReplaceInput(0, n1);  // self-reference.
+
+    CHECK_EQ(0, n0->UseCount());
+    CHECK_EQ(1, n1->UseCount());
+    n1->RemoveAllInputs();
+    CHECK_EQ(1, n1->InputCount());
+    CHECK_EQ(0, n1->UseCount());
+    CHECK_EQ(NULL, n1->InputAt(0));
+  }
+}