[turbofan] Proper dead code elimination as regular reducer.

test/cctest/compiler/test-control-reducer.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/base/bits.h"
-#include "src/compiler/all-nodes.h"
-#include "src/compiler/common-operator.h"
-#include "src/compiler/control-reducer.h"
-#include "src/compiler/graph.h"
-#include "src/compiler/js-graph.h"
-#include "src/compiler/node-properties.h"
-
-using namespace v8::internal;
-using namespace v8::internal::compiler;
-
-static const size_t kNumLeafs = 4;
-
-enum Decision { kFalse, kUnknown, kTrue };
-
-// TODO(titzer): convert this whole file into unit tests.
-
-static int CheckInputs(Node* node, Node* i0 = NULL, Node* i1 = NULL,
-                       Node* i2 = NULL) {
-  int count = 3;
-  if (i2 == NULL) count = 2;
-  if (i1 == NULL) count = 1;
-  if (i0 == NULL) count = 0;
-  CHECK_EQ(count, node->InputCount());
-  if (i0 != NULL) CHECK_EQ(i0, node->InputAt(0));
-  if (i1 != NULL) CHECK_EQ(i1, node->InputAt(1));
-  if (i2 != NULL) CHECK_EQ(i2, node->InputAt(2));
-  return count;
-}
-
-
-static int CheckMerge(Node* node, Node* i0 = NULL, Node* i1 = NULL,
-                      Node* i2 = NULL) {
-  CHECK_EQ(IrOpcode::kMerge, node->opcode());
-  int count = CheckInputs(node, i0, i1, i2);
-  CHECK_EQ(count, node->op()->ControlInputCount());
-  return count;
-}
-
-
-static int CheckLoop(Node* node, Node* i0 = NULL, Node* i1 = NULL,
-                     Node* i2 = NULL) {
-  CHECK_EQ(IrOpcode::kLoop, node->opcode());
-  int count = CheckInputs(node, i0, i1, i2);
-  CHECK_EQ(count, node->op()->ControlInputCount());
-  return count;
-}
-
-
-bool IsUsedBy(Node* a, Node* b) {
-  auto const uses = a->uses();
-  return std::find(uses.begin(), uses.end(), b) != uses.end();
-}
-
-
-// A helper for all tests dealing with ControlTester.
-class ControlReducerTester : HandleAndZoneScope {
- public:
-  ControlReducerTester()
-      : isolate(main_isolate()),
-        common(main_zone()),
-        graph(main_zone()),
-        jsgraph(main_isolate(), &graph, &common, NULL, NULL),
-        start(graph.NewNode(common.Start(1))),
-        end(graph.NewNode(common.End(1), start)),
-        p0(graph.NewNode(common.Parameter(0), start)),
-        zero(jsgraph.Int32Constant(0)),
-        one(jsgraph.OneConstant()),
-        half(jsgraph.Constant(0.5)),
-        self(graph.NewNode(common.Int32Constant(0xaabbccdd))),
-        dead(graph.NewNode(common.DeadControl())) {
-    graph.SetEnd(end);
-    graph.SetStart(start);
-    leaf[0] = zero;
-    leaf[1] = one;
-    leaf[2] = half;
-    leaf[3] = p0;
-  }
-
-  Isolate* isolate;
-  CommonOperatorBuilder common;
-  Graph graph;
-  JSGraph jsgraph;
-  Node* start;
-  Node* end;
-  Node* p0;
-  Node* zero;
-  Node* one;
-  Node* half;
-  Node* self;
-  Node* dead;
-  Node* leaf[kNumLeafs];
-
-  Node* Phi(Node* a) {
-    return SetSelfReferences(graph.NewNode(op(1, false), a, start));
-  }
-
-  Node* Phi(Node* a, Node* b) {
-    return SetSelfReferences(graph.NewNode(op(2, false), a, b, start));
-  }
-
-  Node* Phi(Node* a, Node* b, Node* c) {
-    return SetSelfReferences(graph.NewNode(op(3, false), a, b, c, start));
-  }
-
-  Node* Phi(Node* a, Node* b, Node* c, Node* d) {
-    return SetSelfReferences(graph.NewNode(op(4, false), a, b, c, d, start));
-  }
-
-  Node* EffectPhi(Node* a) {
-    return SetSelfReferences(graph.NewNode(op(1, true), a, start));
-  }
-
-  Node* EffectPhi(Node* a, Node* b) {
-    return SetSelfReferences(graph.NewNode(op(2, true), a, b, start));
-  }
-
-  Node* EffectPhi(Node* a, Node* b, Node* c) {
-    return SetSelfReferences(graph.NewNode(op(3, true), a, b, c, start));
-  }
-
-  Node* EffectPhi(Node* a, Node* b, Node* c, Node* d) {
-    return SetSelfReferences(graph.NewNode(op(4, true), a, b, c, d, start));
-  }
-
-  Node* SetSelfReferences(Node* node) {
-    for (Edge edge : node->input_edges()) {
-      if (edge.to() == self) node->ReplaceInput(edge.index(), node);
-    }
-    return node;
-  }
-
-  const Operator* op(int count, bool effect) {
-    return effect ? common.EffectPhi(count) : common.Phi(kMachAnyTagged, count);
-  }
-
-  void ReduceGraph() { ControlReducer::ReduceGraph(main_zone(), &jsgraph); }
-
-  void ReduceMerge(Node* expect, Node* merge) {
-    Node* result = ControlReducer::ReduceMerge(&jsgraph, merge);
-    CHECK_EQ(expect, result);
-  }
-
-  void ReduceMergeIterative(Node* expect, Node* merge) {
-    p0->ReplaceInput(0, start);  // hack: parameters may be trimmed.
-    Node* end = graph.NewNode(common.End(1), merge);
-    graph.SetEnd(end);
-    ReduceGraph();
-    CheckInputs(end, expect);
-  }
-
-  void ReduceBranch(Decision expected, Node* branch) {
-    Node* control = branch->InputAt(1);
-    for (Node* use : branch->uses()) {
-      if (use->opcode() == IrOpcode::kIfTrue) {
-        Node* result = ControlReducer::ReduceIfNodeForTesting(&jsgraph, use);
-        if (expected == kTrue) CHECK_EQ(control, result);
-        if (expected == kFalse) {
-          CHECK_EQ(IrOpcode::kDeadControl, result->opcode());
-        }
-        if (expected == kUnknown) CHECK_EQ(use, result);
-      } else if (use->opcode() == IrOpcode::kIfFalse) {
-        Node* result = ControlReducer::ReduceIfNodeForTesting(&jsgraph, use);
-        if (expected == kFalse) CHECK_EQ(control, result);
-        if (expected == kTrue) {
-          CHECK_EQ(IrOpcode::kDeadControl, result->opcode());
-        }
-        if (expected == kUnknown) CHECK_EQ(use, result);
-      } else {
-        UNREACHABLE();
-      }
-    }
-  }
-
-  Node* Return(Node* val, Node* effect, Node* control) {
-    Node* ret = graph.NewNode(common.Return(), val, effect, control);
-    end->ReplaceInput(0, ret);
-    return ret;
-  }
-};
-
-
-struct Branch {
-  Node* branch;
-  Node* if_true;
-  Node* if_false;
-
-  Branch(ControlReducerTester& R, Node* cond, Node* control = NULL) {
-    if (control == NULL) control = R.start;
-    branch = R.graph.NewNode(R.common.Branch(), cond, control);
-    if_true = R.graph.NewNode(R.common.IfTrue(), branch);
-    if_false = R.graph.NewNode(R.common.IfFalse(), branch);
-  }
-};
-
-
-// TODO(titzer): use the diamonds from src/compiler/diamond.h here.
-struct Diamond {
-  Node* branch;
-  Node* if_true;
-  Node* if_false;
-  Node* merge;
-  Node* phi;
-
-  Diamond(ControlReducerTester& R, Node* cond) {
-    branch = R.graph.NewNode(R.common.Branch(), cond, R.start);
-    if_true = R.graph.NewNode(R.common.IfTrue(), branch);
-    if_false = R.graph.NewNode(R.common.IfFalse(), branch);
-    merge = R.graph.NewNode(R.common.Merge(2), if_true, if_false);
-    phi = NULL;
-  }
-
-  Diamond(ControlReducerTester& R, Node* cond, Node* tv, Node* fv) {
-    branch = R.graph.NewNode(R.common.Branch(), cond, R.start);
-    if_true = R.graph.NewNode(R.common.IfTrue(), branch);
-    if_false = R.graph.NewNode(R.common.IfFalse(), branch);
-    merge = R.graph.NewNode(R.common.Merge(2), if_true, if_false);
-    phi = R.graph.NewNode(R.common.Phi(kMachAnyTagged, 2), tv, fv, merge);
-  }
-
-  void chain(Diamond& that) { branch->ReplaceInput(1, that.merge); }
-
-  // Nest {this} into either the if_true or if_false branch of {that}.
-  void nest(Diamond& that, bool if_true) {
-    if (if_true) {
-      branch->ReplaceInput(1, that.if_true);
-      that.merge->ReplaceInput(0, merge);
-    } else {
-      branch->ReplaceInput(1, that.if_false);
-      that.merge->ReplaceInput(1, merge);
-    }
-  }
-};
-
-
-struct While {
-  Node* branch;
-  Node* if_true;
-  Node* exit;
-  Node* loop;
-
-  While(ControlReducerTester& R, Node* cond) {
-    loop = R.graph.NewNode(R.common.Loop(2), R.start, R.start);
-    branch = R.graph.NewNode(R.common.Branch(), cond, loop);
-    if_true = R.graph.NewNode(R.common.IfTrue(), branch);
-    exit = R.graph.NewNode(R.common.IfFalse(), branch);
-    loop->ReplaceInput(1, if_true);
-  }
-
-  void chain(Node* control) { loop->ReplaceInput(0, control); }
-};
-
-
-// Helper for checking that nodes are *not* reachable from end.
-struct DeadChecker {
-  Zone zone;
-  AllNodes nodes;
-  explicit DeadChecker(Graph* graph) : zone(), nodes(&zone, graph) {}
-
-  void Check(Node* node) { CHECK(!nodes.IsLive(node)); }
-
-  void Check(Diamond& d) {
-    Check(d.branch);
-    Check(d.if_true);
-    Check(d.if_false);
-    Check(d.merge);
-    if (d.phi != NULL) Check(d.phi);
-  }
-
-  void CheckLive(Diamond& d, bool live_phi = true) {
-    CheckInputs(d.merge, d.if_true, d.if_false);
-    CheckInputs(d.if_true, d.branch);
-    CheckInputs(d.if_false, d.branch);
-    if (d.phi != NULL) {
-      if (live_phi) {
-        CHECK_EQ(3, d.phi->InputCount());
-        CHECK_EQ(d.merge, d.phi->InputAt(2));
-      } else {
-        Check(d.phi);
-      }
-    }
-  }
-};
-
-
-TEST(CMergeReduce_simple1) {
-  ControlReducerTester R;
-
-  Node* merge = R.graph.NewNode(R.common.Merge(1), R.start);
-  R.ReduceMerge(R.start, merge);
-}
-
-
-TEST(CMergeReduce_simple2) {
-  ControlReducerTester R;
-
-  Node* merge1 = R.graph.NewNode(R.common.Merge(1), R.start);
-  Node* merge2 = R.graph.NewNode(R.common.Merge(1), merge1);
-  R.ReduceMerge(merge1, merge2);
-  R.ReduceMergeIterative(R.start, merge2);
-}
-
-
-TEST(CMergeReduce_none1) {
-  ControlReducerTester R;
-
-  Node* merge = R.graph.NewNode(R.common.Merge(2), R.start, R.start);
-  R.ReduceMerge(merge, merge);
-}
-
-
-TEST(CMergeReduce_none2) {
-  ControlReducerTester R;
-
-  Node* t1 = R.graph.NewNode(R.common.IfTrue(), R.start);
-  Node* t2 = R.graph.NewNode(R.common.IfTrue(), R.start);
-  Node* merge = R.graph.NewNode(R.common.Merge(2), t1, t2);
-  R.ReduceMerge(merge, merge);
-}
-
-
-TEST(CMergeReduce_self3) {
-  ControlReducerTester R;
-
-  Node* merge =
-      R.SetSelfReferences(R.graph.NewNode(R.common.Merge(2), R.start, R.self));
-  R.ReduceMerge(merge, merge);
-}
-
-
-TEST(CMergeReduce_dead1) {
-  ControlReducerTester R;
-
-  Node* merge = R.graph.NewNode(R.common.Merge(2), R.start, R.dead);
-  R.ReduceMerge(R.start, merge);
-}
-
-
-TEST(CMergeReduce_dead2) {
-  ControlReducerTester R;
-
-  Node* merge1 = R.graph.NewNode(R.common.Merge(1), R.start);
-  Node* merge2 = R.graph.NewNode(R.common.Merge(2), merge1, R.dead);
-  R.ReduceMerge(merge1, merge2);
-  R.ReduceMergeIterative(R.start, merge2);
-}
-
-
-TEST(CMergeReduce_dead_rm1a) {
-  ControlReducerTester R;
-
-  for (int i = 0; i < 3; i++) {
-    Node* merge = R.graph.NewNode(R.common.Merge(3), R.start, R.start, R.start);
-    merge->ReplaceInput(i, R.dead);
-    R.ReduceMerge(merge, merge);
-    CheckMerge(merge, R.start, R.start);
-  }
-}
-
-
-TEST(CMergeReduce_dead_rm1b) {
-  ControlReducerTester R;
-
-  Node* t = R.graph.NewNode(R.common.IfTrue(), R.start);
-  Node* f = R.graph.NewNode(R.common.IfTrue(), R.start);
-  for (int i = 0; i < 2; i++) {
-    for (int j = i + 1; j < 3; j++) {
-      Node* merge = R.graph.NewNode(R.common.Merge(3), R.dead, R.dead, R.dead);
-      merge->ReplaceInput(i, t);
-      merge->ReplaceInput(j, f);
-      R.ReduceMerge(merge, merge);
-      CheckMerge(merge, t, f);
-    }
-  }
-}
-
-
-TEST(CMergeReduce_dead_rm2) {
-  ControlReducerTester R;
-
-  for (int i = 0; i < 3; i++) {
-    Node* merge = R.graph.NewNode(R.common.Merge(3), R.dead, R.dead, R.dead);
-    merge->ReplaceInput(i, R.start);
-    R.ReduceMerge(R.start, merge);
-  }
-}
-
-
-TEST(CLoopReduce_dead_rm1) {
-  ControlReducerTester R;
-
-  for (int i = 0; i < 3; i++) {
-    Node* loop = R.graph.NewNode(R.common.Loop(3), R.dead, R.start, R.start);
-    R.ReduceMerge(loop, loop);
-    CheckLoop(loop, R.start, R.start);
-  }
-}
-
-
-TEST(CMergeReduce_edit_phi1) {
-  ControlReducerTester R;
-
-  for (int i = 0; i < 3; i++) {
-    Node* merge = R.graph.NewNode(R.common.Merge(3), R.start, R.start, R.start);
-    merge->ReplaceInput(i, R.dead);
-    Node* phi = R.graph.NewNode(R.common.Phi(kMachAnyTagged, 3), R.leaf[0],
-                                R.leaf[1], R.leaf[2], merge);
-    R.ReduceMerge(merge, merge);
-    CHECK_EQ(IrOpcode::kPhi, phi->opcode());
-    CHECK_EQ(2, phi->op()->ValueInputCount());
-    CHECK_EQ(3, phi->InputCount());
-    CHECK_EQ(R.leaf[i < 1 ? 1 : 0], phi->InputAt(0));
-    CHECK_EQ(R.leaf[i < 2 ? 2 : 1], phi->InputAt(1));
-    CHECK_EQ(merge, phi->InputAt(2));
-  }
-}
-
-
-TEST(CMergeReduce_edit_effect_phi1) {
-  ControlReducerTester R;
-
-  for (int i = 0; i < 3; i++) {
-    Node* merge = R.graph.NewNode(R.common.Merge(3), R.start, R.start, R.start);
-    merge->ReplaceInput(i, R.dead);
-    Node* phi = R.graph.NewNode(R.common.EffectPhi(3), R.leaf[0], R.leaf[1],
-                                R.leaf[2], merge);
-    R.ReduceMerge(merge, merge);
-    CHECK_EQ(IrOpcode::kEffectPhi, phi->opcode());
-    CHECK_EQ(0, phi->op()->ValueInputCount());
-    CHECK_EQ(2, phi->op()->EffectInputCount());
-    CHECK_EQ(3, phi->InputCount());
-    CHECK_EQ(R.leaf[i < 1 ? 1 : 0], phi->InputAt(0));
-    CHECK_EQ(R.leaf[i < 2 ? 2 : 1], phi->InputAt(1));
-    CHECK_EQ(merge, phi->InputAt(2));
-  }
-}
-
-
-static const int kSelectorSize = 4;
-
-// Helper to select K of N nodes according to a mask, useful for the test below.
-struct Selector {
-  int mask;
-  int count;
-  explicit Selector(int m) {
-    mask = m;
-    count = v8::base::bits::CountPopulation32(m);
-  }
-  bool is_selected(int i) { return (mask & (1 << i)) != 0; }
-  void CheckNode(Node* node, IrOpcode::Value opcode, Node** inputs,
-                 Node* control) {
-    CHECK_EQ(opcode, node->opcode());
-    CHECK_EQ(count + (control != NULL ? 1 : 0), node->InputCount());
-    int index = 0;
-    for (int i = 0; i < kSelectorSize; i++) {
-      if (mask & (1 << i)) {
-        CHECK_EQ(inputs[i], node->InputAt(index++));
-      }
-    }
-    CHECK_EQ(count, index);
-    if (control != NULL) CHECK_EQ(control, node->InputAt(index++));
-  }
-  int single_index() {
-    CHECK_EQ(1, count);
-    return WhichPowerOf2(mask);
-  }
-};
-
-
-TEST(CMergeReduce_exhaustive_4) {
-  ControlReducerTester R;
-  Node* controls[] = {
-      R.graph.NewNode(R.common.Start(1)), R.graph.NewNode(R.common.Start(2)),
-      R.graph.NewNode(R.common.Start(3)), R.graph.NewNode(R.common.Start(4))};
-  Node* values[] = {R.jsgraph.Int32Constant(11), R.jsgraph.Int32Constant(22),
-                    R.jsgraph.Int32Constant(33), R.jsgraph.Int32Constant(44)};
-  Node* effects[] = {
-      R.jsgraph.Float64Constant(123.4), R.jsgraph.Float64Constant(223.4),
-      R.jsgraph.Float64Constant(323.4), R.jsgraph.Float64Constant(423.4)};
-
-  for (int mask = 0; mask < (1 << (kSelectorSize - 1)); mask++) {
-    // Reduce a single merge with a given mask.
-    Node* merge = R.graph.NewNode(R.common.Merge(4), controls[0], controls[1],
-                                  controls[2], controls[3]);
-    Node* phi = R.graph.NewNode(R.common.Phi(kMachAnyTagged, 4), values[0],
-                                values[1], values[2], values[3], merge);
-    Node* ephi = R.graph.NewNode(R.common.EffectPhi(4), effects[0], effects[1],
-                                 effects[2], effects[3], merge);
-
-    Node* phi_use =
-        R.graph.NewNode(R.common.Phi(kMachAnyTagged, 1), phi, R.start);
-    Node* ephi_use = R.graph.NewNode(R.common.EffectPhi(1), ephi, R.start);
-
-    Selector selector(mask);
-
-    for (int i = 0; i < kSelectorSize; i++) {  // set up dead merge inputs.
-      if (!selector.is_selected(i)) merge->ReplaceInput(i, R.dead);
-    }
-
-    Node* result = ControlReducer::ReduceMerge(&R.jsgraph, merge);
-
-    int count = selector.count;
-    if (count == 0) {
-      // result should be dead.
-      CHECK_EQ(IrOpcode::kDeadControl, result->opcode());
-    } else if (count == 1) {
-      // merge should be replaced with one of the controls.
-      CHECK_EQ(controls[selector.single_index()], result);
-      // Phis should have been directly replaced.
-      CHECK_EQ(values[selector.single_index()], phi_use->InputAt(0));
-      CHECK_EQ(effects[selector.single_index()], ephi_use->InputAt(0));
-    } else {
-      // Otherwise, nodes should be edited in place.
-      CHECK_EQ(merge, result);
-      selector.CheckNode(merge, IrOpcode::kMerge, controls, NULL);
-      selector.CheckNode(phi, IrOpcode::kPhi, values, merge);
-      selector.CheckNode(ephi, IrOpcode::kEffectPhi, effects, merge);
-      CHECK_EQ(phi, phi_use->InputAt(0));
-      CHECK_EQ(ephi, ephi_use->InputAt(0));
-      CHECK_EQ(count, phi->op()->ValueInputCount());
-      CHECK_EQ(count + 1, phi->InputCount());
-      CHECK_EQ(count, ephi->op()->EffectInputCount());
-      CHECK_EQ(count + 1, ephi->InputCount());
-    }
-  }
-}
-
-
-TEST(CMergeReduce_edit_many_phis1) {
-  ControlReducerTester R;
-
-  const int kPhiCount = 10;
-  Node* phis[kPhiCount];
-
-  for (int i = 0; i < 3; i++) {
-    Node* merge = R.graph.NewNode(R.common.Merge(3), R.start, R.start, R.start);
-    merge->ReplaceInput(i, R.dead);
-    for (int j = 0; j < kPhiCount; j++) {
-      phis[j] = R.graph.NewNode(R.common.Phi(kMachAnyTagged, 3), R.leaf[0],
-                                R.leaf[1], R.leaf[2], merge);
-    }
-    R.ReduceMerge(merge, merge);
-    for (int j = 0; j < kPhiCount; j++) {
-      Node* phi = phis[j];
-      CHECK_EQ(IrOpcode::kPhi, phi->opcode());
-      CHECK_EQ(2, phi->op()->ValueInputCount());
-      CHECK_EQ(3, phi->InputCount());
-      CHECK_EQ(R.leaf[i < 1 ? 1 : 0], phi->InputAt(0));
-      CHECK_EQ(R.leaf[i < 2 ? 2 : 1], phi->InputAt(1));
-      CHECK_EQ(merge, phi->InputAt(2));
-    }
-  }
-}
-
-
-TEST(CMergeReduce_simple_chain1) {
-  ControlReducerTester R;
-  for (int i = 0; i < 5; i++) {
-    Node* merge = R.graph.NewNode(R.common.Merge(1), R.start);
-    for (int j = 0; j < i; j++) {
-      merge = R.graph.NewNode(R.common.Merge(1), merge);
-    }
-    R.ReduceMergeIterative(R.start, merge);
-  }
-}
-
-
-TEST(CMergeReduce_dead_chain1) {
-  ControlReducerTester R;
-  for (int i = 0; i < 5; i++) {
-    Node* merge = R.graph.NewNode(R.common.Merge(1), R.dead);
-    for (int j = 0; j < i; j++) {
-      merge = R.graph.NewNode(R.common.Merge(1), merge);
-    }
-    Node* end = R.graph.NewNode(R.common.End(1), merge);
-    R.graph.SetEnd(end);
-    R.ReduceGraph();
-    CHECK(merge->IsDead());
-    CHECK(!end->InputAt(0));  // end dies.
-  }
-}
-
-
-TEST(CMergeReduce_dead_chain2) {
-  ControlReducerTester R;
-  for (int i = 0; i < 5; i++) {
-    Node* merge = R.graph.NewNode(R.common.Merge(1), R.start);
-    for (int j = 0; j < i; j++) {
-      merge = R.graph.NewNode(R.common.Merge(2), merge, R.dead);
-    }
-    R.ReduceMergeIterative(R.start, merge);
-  }
-}
-
-
-TEST(CBranchReduce_none1) {
-  ControlReducerTester R;
-  Diamond d(R, R.p0);
-  R.ReduceBranch(kUnknown, d.branch);
-}
-
-
-TEST(CBranchReduce_none2) {
-  ControlReducerTester R;
-  Diamond d1(R, R.p0);
-  Diamond d2(R, R.p0);
-  d2.chain(d1);
-  R.ReduceBranch(kUnknown, d2.branch);
-}
-
-
-TEST(CBranchReduce_true) {
-  ControlReducerTester R;
-  Node* true_values[] = {R.jsgraph.Int32Constant(2),
-                         R.jsgraph.Int64Constant(0x7fffffff),
-                         R.jsgraph.TrueConstant()};
-  for (size_t i = 0; i < arraysize(true_values); i++) {
-    Diamond d(R, true_values[i]);
-    R.ReduceBranch(kTrue, d.branch);
-  }
-}
-
-
-TEST(CBranchReduce_false) {
-  ControlReducerTester R;
-  Node* false_values[] = {R.jsgraph.Int32Constant(0),
-                          R.jsgraph.Int64Constant(0),
-                          R.jsgraph.FalseConstant()};
-  for (size_t i = 0; i < arraysize(false_values); i++) {
-    Diamond d(R, false_values[i]);
-    R.ReduceBranch(kFalse, d.branch);
-  }
-}
-
-
-TEST(CDiamondReduce_true) {
-  ControlReducerTester R;
-  Diamond d1(R, R.jsgraph.TrueConstant());
-  R.ReduceMergeIterative(R.start, d1.merge);
-}
-
-
-TEST(CDiamondReduce_false) {
-  ControlReducerTester R;
-  Diamond d2(R, R.jsgraph.FalseConstant());
-  R.ReduceMergeIterative(R.start, d2.merge);
-}
-
-
-TEST(CChainedDiamondsReduce_true_false) {
-  ControlReducerTester R;
-  Diamond d1(R, R.jsgraph.TrueConstant());
-  Diamond d2(R, R.jsgraph.FalseConstant());
-  d2.chain(d1);
-
-  R.ReduceMergeIterative(R.start, d2.merge);
-}
-
-
-TEST(CChainedDiamondsReduce_x_false) {
-  ControlReducerTester R;
-  Diamond d1(R, R.p0);
-  Diamond d2(R, R.jsgraph.FalseConstant());
-  d2.chain(d1);
-
-  R.ReduceMergeIterative(R.start, d2.merge);
-}
-
-
-TEST(CChainedDiamondsReduce_false_x) {
-  ControlReducerTester R;
-  Diamond d1(R, R.zero);
-  Diamond d2(R, R.p0);
-  d2.chain(d1);
-
-  R.ReduceMergeIterative(R.start, d2.merge);
-}
-
-
-TEST(CChainedDiamondsReduce_phi1) {
-  ControlReducerTester R;
-  Diamond d1(R, R.zero, R.one, R.zero);  // foldable branch, phi.
-  Diamond d2(R, d1.phi);
-  d2.chain(d1);
-
-  R.ReduceMergeIterative(R.start, d2.merge);
-}
-
-
-TEST(CNestedDiamondsReduce_true_true_false) {
-  ControlReducerTester R;
-  Diamond d1(R, R.jsgraph.TrueConstant());
-  Diamond d2(R, R.jsgraph.FalseConstant());
-  d2.nest(d1, true);
-
-  R.ReduceMergeIterative(R.start, d1.merge);
-}
-
-
-TEST(CNestedDiamondsReduce_false_true_false) {
-  ControlReducerTester R;
-  Diamond d1(R, R.jsgraph.TrueConstant());
-  Diamond d2(R, R.jsgraph.FalseConstant());
-  d2.nest(d1, false);
-
-  R.ReduceMergeIterative(R.start, d1.merge);
-}
-
-
-TEST(CNestedDiamonds_xyz) {
-  ControlReducerTester R;
-
-  for (int a = 0; a < 2; a++) {
-    for (int b = 0; b < 2; b++) {
-      for (int c = 0; c < 2; c++) {
-        Diamond d1(R, R.jsgraph.Int32Constant(a));
-        Diamond d2(R, R.jsgraph.Int32Constant(b));
-        d2.nest(d1, c);
-
-        R.ReduceMergeIterative(R.start, d1.merge);
-      }
-    }
-  }
-}
-
-
-TEST(CUnusedDiamond1) {
-  ControlReducerTester R;
-  // if (p0) { } else { }
-  Node* branch = R.graph.NewNode(R.common.Branch(), R.p0, R.start);
-  Node* if_true = R.graph.NewNode(R.common.IfTrue(), branch);
-  Node* if_false = R.graph.NewNode(R.common.IfFalse(), branch);
-  Node* merge = R.graph.NewNode(R.common.Merge(2), if_true, if_false);
-  R.ReduceMergeIterative(R.start, merge);
-}
-
-
-TEST(CUnusedDiamond2) {
-  ControlReducerTester R;
-  // if (p0) { } else { }
-  Node* branch = R.graph.NewNode(R.common.Branch(), R.p0, R.start);
-  Node* if_true = R.graph.NewNode(R.common.IfTrue(), branch);
-  Node* if_false = R.graph.NewNode(R.common.IfFalse(), branch);
-  Node* merge = R.graph.NewNode(R.common.Merge(2), if_false, if_true);
-  R.ReduceMergeIterative(R.start, merge);
-}
-
-
-TEST(CDeadLoop1) {
-  ControlReducerTester R;
-
-  While w(R, R.p0);
-  Diamond d(R, R.zero);
-  // if (0) { while (p0) ; } else { }
-  w.branch->ReplaceInput(1, d.if_true);
-  d.merge->ReplaceInput(0, w.exit);
-
-  R.ReduceMergeIterative(R.start, d.merge);
-
-  DeadChecker dead(&R.graph);
-  dead.Check(d);
-  dead.Check(w.loop);
-}
-
-
-TEST(Return1) {
-  ControlReducerTester R;
-  Node* ret = R.Return(R.one, R.start, R.start);
-  R.ReduceGraph();
-  CheckInputs(R.graph.end(), ret);
-  CheckInputs(ret, R.one, R.start, R.start);
-}
-
-
-TEST(Return2) {
-  ControlReducerTester R;
-  Diamond d(R, R.jsgraph.TrueConstant());
-  Node* ret = R.Return(R.half, R.start, d.merge);
-  R.ReduceGraph();
-
-  DeadChecker dead(&R.graph);
-  dead.Check(d.branch);
-  dead.Check(d.if_true);
-  dead.Check(d.if_false);
-  dead.Check(d.merge);
-
-  CheckInputs(R.graph.end(), ret);
-  CheckInputs(ret, R.half, R.start, R.start);
-}
-
-
-TEST(Return_true1) {
-  ControlReducerTester R;
-  Diamond d(R, R.jsgraph.TrueConstant(), R.half, R.zero);
-  Node* ret = R.Return(d.phi, R.start, d.merge);
-  R.ReduceGraph();
-
-  DeadChecker dead(&R.graph);
-  dead.Check(d.branch);
-  dead.Check(d.if_true);
-  dead.Check(d.if_false);
-  dead.Check(d.merge);
-  dead.Check(d.phi);
-
-  CheckInputs(R.graph.end(), ret);
-  CheckInputs(ret, R.half, R.start, R.start);
-}
-
-
-TEST(Return_false1) {
-  ControlReducerTester R;
-  Diamond d(R, R.jsgraph.FalseConstant(), R.one, R.half);
-  Node* ret = R.Return(d.phi, R.start, d.merge);
-  R.ReduceGraph();
-
-  DeadChecker dead(&R.graph);
-  dead.Check(d.branch);
-  dead.Check(d.if_true);
-  dead.Check(d.if_false);
-  dead.Check(d.merge);
-  dead.Check(d.phi);
-
-  CheckInputs(R.graph.end(), ret);
-  CheckInputs(ret, R.half, R.start, R.start);
-}
-
-
-TEST(Return_effect1) {
-  ControlReducerTester R;
-  Diamond d(R, R.jsgraph.TrueConstant());
-  Node* e1 = R.jsgraph.Float64Constant(-100.1);
-  Node* e2 = R.jsgraph.Float64Constant(+100.1);
-  Node* effect = R.graph.NewNode(R.common.EffectPhi(2), e1, e2, d.merge);
-  Node* ret = R.Return(R.p0, effect, d.merge);
-  R.ReduceGraph();
-
-  DeadChecker dead(&R.graph);
-  dead.Check(d);
-  dead.Check(effect);
-
-  CheckInputs(R.graph.end(), ret);
-  CheckInputs(ret, R.p0, e1, R.start);
-}
-
-
-TEST(Return_nested_diamonds1) {
-  ControlReducerTester R;
-  Diamond d2(R, R.p0, R.one, R.zero);
-  Diamond d3(R, R.p0, R.one, R.zero);
-  Diamond d1(R, R.p0, d2.phi, d3.phi);
-
-  d2.nest(d1, true);
-  d3.nest(d1, false);
-
-  Node* ret = R.Return(d1.phi, R.start, d1.merge);
-
-  R.ReduceGraph();  // nothing should happen.
-
-  CheckInputs(ret, d1.phi, R.start, d1.merge);
-  CheckInputs(d1.phi, d2.phi, d3.phi, d1.merge);
-  CheckInputs(d1.merge, d2.merge, d3.merge);
-
-  DeadChecker dead(&R.graph);
-  dead.CheckLive(d2);
-  dead.CheckLive(d3);
-}
-
-
-TEST(Return_nested_diamonds1_dead1) {
-  ControlReducerTester R;
-  Diamond d2(R, R.p0);  // dead diamond
-  Diamond d3(R, R.p0, R.one, R.zero);
-  Diamond d1(R, R.p0, R.one, d3.phi);
-
-  d2.nest(d1, true);
-  d3.nest(d1, false);
-
-  Node* ret = R.Return(d1.phi, R.start, d1.merge);
-
-  R.ReduceGraph();
-
-  CheckInputs(ret, d1.phi, R.start, d1.merge);
-  CheckInputs(d1.phi, R.one, d3.phi, d1.merge);
-  CheckInputs(d1.merge, d1.if_true, d3.merge);
-
-  DeadChecker dead(&R.graph);
-  dead.Check(d2);  // d2 was a dead diamond.
-  dead.CheckLive(d3);
-}
-
-
-TEST(Return_nested_diamonds1_dead2) {
-  ControlReducerTester R;
-  Diamond d2(R, R.p0);  // dead diamond
-  Diamond d3(R, R.p0);  // dead diamond
-  Diamond d1(R, R.p0, R.one, R.zero);
-
-  d2.nest(d1, true);
-  d3.nest(d1, false);
-
-  Node* ret = R.Return(d1.phi, R.start, d1.merge);
-
-  R.ReduceGraph();
-
-  CheckInputs(ret, d1.phi, R.start, d1.merge);
-  CheckInputs(d1.phi, R.one, R.zero, d1.merge);
-  CheckInputs(d1.merge, d1.if_true, d1.if_false);
-
-  DeadChecker dead(&R.graph);
-  dead.Check(d2);
-  dead.Check(d3);
-}
-
-
-TEST(Return_nested_diamonds_true1) {
-  ControlReducerTester R;
-  Diamond d2(R, R.p0, R.one, R.zero);
-  Diamond d1(R, R.jsgraph.TrueConstant(), d2.phi, R.zero);
-  Diamond d3(R, R.p0);
-
-  d2.nest(d1, true);
-  d3.nest(d1, false);
-
-  Node* ret = R.Return(d1.phi, R.start, d1.merge);
-
-  R.ReduceGraph();  // d1 gets folded true.
-
-  CheckInputs(ret, d2.phi, R.start, d2.merge);
-  CheckInputs(d2.branch, R.p0, R.start);
-
-  DeadChecker dead(&R.graph);
-  dead.Check(d1);
-  dead.CheckLive(d2);
-  dead.Check(d3);
-}
-
-
-TEST(Return_nested_diamonds_false1) {
-  ControlReducerTester R;
-  Diamond d3(R, R.p0, R.one, R.zero);
-  Diamond d1(R, R.zero, R.one, d3.phi);
-  Diamond d2(R, R.p0);
-
-  d2.nest(d1, true);
-  d3.nest(d1, false);
-
-  Node* ret = R.Return(d1.phi, R.start, d1.merge);
-
-  R.ReduceGraph();  // d1 gets folded false.
-
-  CheckInputs(ret, d3.phi, R.start, d3.merge);
-  CheckInputs(d3.branch, R.p0, R.start);
-
-  DeadChecker dead(&R.graph);
-  dead.Check(d1);
-  dead.Check(d2);
-  dead.CheckLive(d3);
-}
-
-
-TEST(Return_nested_diamonds_true_true1) {
-  ControlReducerTester R;
-  Diamond d1(R, R.jsgraph.TrueConstant(), R.one, R.zero);
-  Diamond d2(R, R.jsgraph.TrueConstant());
-  Diamond d3(R, R.p0);
-
-  d2.nest(d1, true);
-  d3.nest(d1, false);
-
-  Node* ret = R.Return(d1.phi, R.start, d1.merge);
-
-  R.ReduceGraph();  // d1 and d2 both get folded true.
-
-  CheckInputs(ret, R.one, R.start, R.start);
-
-  DeadChecker dead(&R.graph);
-  dead.Check(d1);
-  dead.Check(d2);
-  dead.Check(d3);
-}
-
-
-TEST(Return_nested_diamonds_true_false1) {
-  ControlReducerTester R;
-  Diamond d1(R, R.jsgraph.TrueConstant(), R.one, R.zero);
-  Diamond d2(R, R.jsgraph.FalseConstant());
-  Diamond d3(R, R.p0);
-
-  d2.nest(d1, true);
-  d3.nest(d1, false);
-
-  Node* ret = R.Return(d1.phi, R.start, d1.merge);
-
-  R.ReduceGraph();  // d1 gets folded true and d2 gets folded false.
-
-  CheckInputs(ret, R.one, R.start, R.start);
-
-  DeadChecker dead(&R.graph);
-  dead.Check(d1);
-  dead.Check(d2);
-  dead.Check(d3);
-}
-
-
-TEST(Return_nested_diamonds2) {
-  ControlReducerTester R;
-  Node* x2 = R.jsgraph.Float64Constant(11.1);
-  Node* y2 = R.jsgraph.Float64Constant(22.2);
-  Node* x3 = R.jsgraph.Float64Constant(33.3);
-  Node* y3 = R.jsgraph.Float64Constant(44.4);
-
-  Diamond d2(R, R.p0, x2, y2);
-  Diamond d3(R, R.p0, x3, y3);
-  Diamond d1(R, R.p0, d2.phi, d3.phi);
-
-  d2.nest(d1, true);
-  d3.nest(d1, false);
-
-  Node* ret = R.Return(d1.phi, R.start, d1.merge);
-
-  R.ReduceGraph();  // nothing should happen.
-
-  CheckInputs(ret, d1.phi, R.start, d1.merge);
-  CheckInputs(d1.phi, d2.phi, d3.phi, d1.merge);
-  CheckInputs(d1.merge, d2.merge, d3.merge);
-
-  DeadChecker dead(&R.graph);
-  dead.CheckLive(d2);
-  dead.CheckLive(d3);
-}
-
-
-TEST(Return_nested_diamonds_true2) {
-  ControlReducerTester R;
-  Node* x2 = R.jsgraph.Float64Constant(11.1);
-  Node* y2 = R.jsgraph.Float64Constant(22.2);
-  Node* x3 = R.jsgraph.Float64Constant(33.3);
-  Node* y3 = R.jsgraph.Float64Constant(44.4);
-
-  Diamond d2(R, R.p0, x2, y2);
-  Diamond d3(R, R.p0, x3, y3);
-  Diamond d1(R, R.jsgraph.TrueConstant(), d2.phi, d3.phi);
-
-  d2.nest(d1, true);
-  d3.nest(d1, false);
-
-  Node* ret = R.Return(d1.phi, R.start, d1.merge);
-
-  R.ReduceGraph();  // d1 gets folded true.
-
-  CheckInputs(ret, d2.phi, R.start, d2.merge);
-  CheckInputs(d2.branch, R.p0, R.start);
-
-  DeadChecker dead(&R.graph);
-  dead.Check(d1);
-  dead.CheckLive(d2);
-  dead.Check(d3);
-}
-
-
-TEST(Return_nested_diamonds_true_true2) {
-  ControlReducerTester R;
-  Node* x2 = R.jsgraph.Float64Constant(11.1);
-  Node* y2 = R.jsgraph.Float64Constant(22.2);
-  Node* x3 = R.jsgraph.Float64Constant(33.3);
-  Node* y3 = R.jsgraph.Float64Constant(44.4);
-
-  Diamond d2(R, R.jsgraph.TrueConstant(), x2, y2);
-  Diamond d3(R, R.p0, x3, y3);
-  Diamond d1(R, R.jsgraph.TrueConstant(), d2.phi, d3.phi);
-
-  d2.nest(d1, true);
-  d3.nest(d1, false);
-
-  Node* ret = R.Return(d1.phi, R.start, d1.merge);
-
-  R.ReduceGraph();  // d1 gets folded true.
-
-  CheckInputs(ret, x2, R.start, R.start);
-
-  DeadChecker dead(&R.graph);
-  dead.Check(d1);
-  dead.Check(d2);
-  dead.Check(d3);
-}
-
-
-TEST(Return_nested_diamonds_true_false2) {
-  ControlReducerTester R;
-  Node* x2 = R.jsgraph.Float64Constant(11.1);
-  Node* y2 = R.jsgraph.Float64Constant(22.2);
-  Node* x3 = R.jsgraph.Float64Constant(33.3);
-  Node* y3 = R.jsgraph.Float64Constant(44.4);
-
-  Diamond d2(R, R.jsgraph.FalseConstant(), x2, y2);
-  Diamond d3(R, R.p0, x3, y3);
-  Diamond d1(R, R.jsgraph.TrueConstant(), d2.phi, d3.phi);
-
-  d2.nest(d1, true);
-  d3.nest(d1, false);
-
-  Node* ret = R.Return(d1.phi, R.start, d1.merge);
-
-  R.ReduceGraph();  // d1 gets folded true.
-
-  CheckInputs(ret, y2, R.start, R.start);
-
-  DeadChecker dead(&R.graph);
-  dead.Check(d1);
-  dead.Check(d2);
-  dead.Check(d3);
-}