llvm/unittests/ADT/PostOrderIteratorTest.cpp

//===- PostOrderIteratorTest.cpp - PostOrderIterator unit tests -----------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/CFG.h"
#include "gtest/gtest.h"
#include "TestGraph.h"

#include <array>
#include <iterator>
#include <type_traits>

#include <cstddef>

using namespace llvm;

namespace {

// Whether we're able to compile
TEST(PostOrderIteratorTest, Compiles) {
  Graph<6> G;
  using NodeType = Graph<6>::NodeType;
  NodeType *NullNode = nullptr;

  auto PI = post_order(G);
  PI.insertEdge(std::optional<NodeType *>(), NullNode);

  using ExtSetTy = SmallPtrSet<void *, 4>;
  ExtSetTy Ext;
  auto PIExt = post_order_ext(G, Ext);
  PIExt.insertEdge(std::optional<NodeType *>(), NullNode);
}

static_assert(std::is_convertible_v<
              decltype(*post_order(std::declval<Graph<3>>()).begin()),
              PostOrderTraversal<Graph<3>>::iterator::reference>);

// Test post-order and reverse post-order traversals for simple graph type.
TEST(PostOrderIteratorTest, PostOrderAndReversePostOrderTraverrsal) {
  Graph<6> G;
  G.AddEdge(0, 1);
  G.AddEdge(0, 2);
  G.AddEdge(0, 3);
  G.AddEdge(1, 4);
  G.AddEdge(2, 5);
  G.AddEdge(5, 2);
  G.AddEdge(2, 4);
  G.AddEdge(1, 4);

  SmallVector<int> FromIterator;
  for (auto N : post_order(G))
    FromIterator.push_back(N->first);
  EXPECT_EQ(6u, FromIterator.size());
  EXPECT_EQ(4, FromIterator[0]);
  EXPECT_EQ(1, FromIterator[1]);
  EXPECT_EQ(5, FromIterator[2]);
  EXPECT_EQ(2, FromIterator[3]);
  EXPECT_EQ(3, FromIterator[4]);
  EXPECT_EQ(0, FromIterator[5]);
  FromIterator.clear();

  ReversePostOrderTraversal<Graph<6>> RPOT(G);
  for (auto N : RPOT)
    FromIterator.push_back(N->first);
  EXPECT_EQ(6u, FromIterator.size());
  EXPECT_EQ(0, FromIterator[0]);
  EXPECT_EQ(3, FromIterator[1]);
  EXPECT_EQ(2, FromIterator[2]);
  EXPECT_EQ(5, FromIterator[3]);
  EXPECT_EQ(1, FromIterator[4]);
  EXPECT_EQ(4, FromIterator[5]);
}
}