Restrict floating control to minimal control-connected component.

test/unittests/compiler/control-equivalence-unittest.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/compiler/control-equivalence.h"
+#include "src/compiler/graph-visualizer.h"
+#include "src/compiler/node-properties-inl.h"
+#include "src/zone-containers.h"
+#include "test/unittests/compiler/graph-unittest.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+#define ASSERT_EQUIVALENCE(...)                           \
+  do {                                                    \
+    Node* __n[] = {__VA_ARGS__};                          \
+    ASSERT_TRUE(IsEquivalenceClass(arraysize(__n), __n)); \
+  } while (false);
+
+class ControlEquivalenceTest : public GraphTest {
+ public:
+  ControlEquivalenceTest() : all_nodes_(zone()), classes_(zone()) {
+    Store(graph()->start());
+  }
+
+ protected:
+  void ComputeEquivalence(Node* node) {
+    graph()->SetEnd(graph()->NewNode(common()->End(), node));
+    if (FLAG_trace_turbo) {
+      OFStream os(stdout);
+      os << AsDOT(*graph());
+    }
+    ControlEquivalence equivalence(zone(), graph());
+    equivalence.Run(node);
+    classes_.resize(graph()->NodeCount());
+    for (Node* node : all_nodes_) {
+      classes_[node->id()] = equivalence.ClassOf(node);
+    }
+  }
+
+  bool IsEquivalenceClass(size_t length, Node** nodes) {
+    BitVector in_class(graph()->NodeCount(), zone());
+    size_t expected_class = classes_[nodes[0]->id()];
+    for (size_t i = 0; i < length; ++i) {
+      in_class.Add(nodes[i]->id());
+    }
+    for (Node* node : all_nodes_) {
+      if (in_class.Contains(node->id())) {
+        if (classes_[node->id()] != expected_class) return false;
+      } else {
+        if (classes_[node->id()] == expected_class) return false;
+      }
+    }
+    return true;
+  }
+
+  Node* Value() { return NumberConstant(0.0); }
+
+  Node* Branch(Node* control) {
+    return Store(graph()->NewNode(common()->Branch(), Value(), control));
+  }
+
+  Node* IfTrue(Node* control) {
+    return Store(graph()->NewNode(common()->IfTrue(), control));
+  }
+
+  Node* IfFalse(Node* control) {
+    return Store(graph()->NewNode(common()->IfFalse(), control));
+  }
+
+  Node* Merge2(Node* control1, Node* control2) {
+    return Store(graph()->NewNode(common()->Merge(2), control1, control2));
+  }
+
+  Node* Loop2(Node* control) {
+    return Store(graph()->NewNode(common()->Loop(2), control, control));
+  }
+
+  Node* End(Node* control) {
+    return Store(graph()->NewNode(common()->End(), control));
+  }
+
+ private:
+  Node* Store(Node* node) {
+    all_nodes_.push_back(node);
+    return node;
+  }
+
+  ZoneVector<Node*> all_nodes_;
+  ZoneVector<size_t> classes_;
+};
+
+
+// -----------------------------------------------------------------------------
+// Test cases.
+
+
+TEST_F(ControlEquivalenceTest, Empty1) {
+  Node* start = graph()->start();
+  ComputeEquivalence(start);
+
+  ASSERT_EQUIVALENCE(start);
+}
+
+
+TEST_F(ControlEquivalenceTest, Empty2) {
+  Node* start = graph()->start();
+  Node* end = End(start);
+  ComputeEquivalence(end);
+
+  ASSERT_EQUIVALENCE(start, end);
+}
+
+
+TEST_F(ControlEquivalenceTest, Diamond1) {
+  Node* start = graph()->start();
+  Node* b = Branch(start);
+  Node* t = IfTrue(b);
+  Node* f = IfFalse(b);
+  Node* m = Merge2(t, f);
+  ComputeEquivalence(m);
+
+  ASSERT_EQUIVALENCE(b, m, start);
+  ASSERT_EQUIVALENCE(f);
+  ASSERT_EQUIVALENCE(t);
+}
+
+
+TEST_F(ControlEquivalenceTest, Diamond2) {
+  Node* start = graph()->start();
+  Node* b1 = Branch(start);
+  Node* t1 = IfTrue(b1);
+  Node* f1 = IfFalse(b1);
+  Node* b2 = Branch(f1);
+  Node* t2 = IfTrue(b2);
+  Node* f2 = IfFalse(b2);
+  Node* m2 = Merge2(t2, f2);
+  Node* m1 = Merge2(t1, m2);
+  ComputeEquivalence(m1);
+
+  ASSERT_EQUIVALENCE(b1, m1, start);
+  ASSERT_EQUIVALENCE(t1);
+  ASSERT_EQUIVALENCE(f1, b2, m2);
+  ASSERT_EQUIVALENCE(t2);
+  ASSERT_EQUIVALENCE(f2);
+}
+
+
+TEST_F(ControlEquivalenceTest, Diamond3) {
+  Node* start = graph()->start();
+  Node* b1 = Branch(start);
+  Node* t1 = IfTrue(b1);
+  Node* f1 = IfFalse(b1);
+  Node* m1 = Merge2(t1, f1);
+  Node* b2 = Branch(m1);
+  Node* t2 = IfTrue(b2);
+  Node* f2 = IfFalse(b2);
+  Node* m2 = Merge2(t2, f2);
+  ComputeEquivalence(m2);
+
+  ASSERT_EQUIVALENCE(b1, m1, b2, m2, start);
+  ASSERT_EQUIVALENCE(t1);
+  ASSERT_EQUIVALENCE(f1);
+  ASSERT_EQUIVALENCE(t2);
+  ASSERT_EQUIVALENCE(f2);
+}
+
+
+TEST_F(ControlEquivalenceTest, Switch1) {
+  Node* start = graph()->start();
+  Node* b1 = Branch(start);
+  Node* t1 = IfTrue(b1);
+  Node* f1 = IfFalse(b1);
+  Node* b2 = Branch(f1);
+  Node* t2 = IfTrue(b2);
+  Node* f2 = IfFalse(b2);
+  Node* b3 = Branch(f2);
+  Node* t3 = IfTrue(b3);
+  Node* f3 = IfFalse(b3);
+  Node* m1 = Merge2(t1, t2);
+  Node* m2 = Merge2(m1, t3);
+  Node* m3 = Merge2(m2, f3);
+  ComputeEquivalence(m3);
+
+  ASSERT_EQUIVALENCE(b1, m3, start);
+  ASSERT_EQUIVALENCE(t1);
+  ASSERT_EQUIVALENCE(f1, b2);
+  ASSERT_EQUIVALENCE(t2);
+  ASSERT_EQUIVALENCE(f2, b3);
+  ASSERT_EQUIVALENCE(t3);
+  ASSERT_EQUIVALENCE(f3);
+  ASSERT_EQUIVALENCE(m1);
+  ASSERT_EQUIVALENCE(m2);
+}
+
+
+TEST_F(ControlEquivalenceTest, Loop1) {
+  Node* start = graph()->start();
+  Node* l = Loop2(start);
+  l->ReplaceInput(1, l);
+  ComputeEquivalence(l);
+
+  ASSERT_EQUIVALENCE(start);
+  ASSERT_EQUIVALENCE(l);
+}
+
+
+TEST_F(ControlEquivalenceTest, Loop2) {
+  Node* start = graph()->start();
+  Node* l = Loop2(start);
+  Node* b = Branch(l);
+  Node* t = IfTrue(b);
+  Node* f = IfFalse(b);
+  l->ReplaceInput(1, t);
+  ComputeEquivalence(f);
+
+  ASSERT_EQUIVALENCE(f, start);
+  ASSERT_EQUIVALENCE(t);
+  ASSERT_EQUIVALENCE(l, b);
+}
+
+
+TEST_F(ControlEquivalenceTest, Irreducible) {
+  Node* start = graph()->start();
+  Node* b1 = Branch(start);
+  Node* t1 = IfTrue(b1);
+  Node* f1 = IfFalse(b1);
+  Node* lp = Loop2(f1);
+  Node* m1 = Merge2(t1, lp);
+  Node* b2 = Branch(m1);
+  Node* t2 = IfTrue(b2);
+  Node* f2 = IfFalse(b2);
+  Node* m2 = Merge2(t2, f2);
+  Node* b3 = Branch(m2);
+  Node* t3 = IfTrue(b3);
+  Node* f3 = IfFalse(b3);
+  lp->ReplaceInput(1, f3);
+  ComputeEquivalence(t3);
+
+  ASSERT_EQUIVALENCE(b1, t3, start);
+  ASSERT_EQUIVALENCE(t1);
+  ASSERT_EQUIVALENCE(f1);
+  ASSERT_EQUIVALENCE(m1, b2, m2, b3);
+  ASSERT_EQUIVALENCE(t2);
+  ASSERT_EQUIVALENCE(f2);
+  ASSERT_EQUIVALENCE(f3);
+  ASSERT_EQUIVALENCE(lp);
+}
+
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8