DeadNodeEliminationTests.cpp

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/*
 * Copyright 2023 Nico Reißmann <nico.reissmann@gmail.com>
 * See COPYING for terms of redistribution.
 */
 
#include <gtest/gtest.h>
 
#include <jlm/hls/backend/rvsdg2rhls/DeadNodeElimination.hpp>
#include <jlm/llvm/ir/operators/lambda.hpp>
#include <jlm/rvsdg/TestType.hpp>
 
TEST(DeadNodeEliminationTests, TestDeadLoopNode)
{
  using namespace jlm::hls;
 
  // Arrange
  auto valueType = jlm::rvsdg::TestType::createValueType();
  auto functionType = jlm::rvsdg::FunctionType::Create(
      { jlm::rvsdg::ControlType::Create(2), valueType },
      { valueType });
 
  jlm::llvm::LlvmRvsdgModule rvsdgModule(jlm::util::FilePath(""), "", "");
  auto & rvsdg = rvsdgModule.Rvsdg();
 
  auto lambdaNode = jlm::rvsdg::LambdaNode::Create(
      rvsdg.GetRootRegion(),
      jlm::llvm::LlvmLambdaOperation::Create(
          functionType,
          "f",
          jlm::llvm::Linkage::externalLinkage));
 
  LoopNode::create(lambdaNode->subregion());
 
  lambdaNode->finalize({ lambdaNode->GetFunctionArguments()[1] });
 
  // Act
  EliminateDeadNodes(rvsdgModule);
 
  // Assert
  EXPECT_EQ(lambdaNode->subregion()->numNodes(), 0u);
}
 
TEST(DeadNodeEliminationTests, TestDeadLoopNodeOutput)
{
  using namespace jlm::hls;
 
  // Arrange
  auto valueType = jlm::rvsdg::TestType::createValueType();
  auto functionType = jlm::rvsdg::FunctionType::Create(
      { jlm::rvsdg::ControlType::Create(2), valueType },
      { jlm::rvsdg::ControlType::Create(2) });
 
  jlm::llvm::LlvmRvsdgModule rvsdgModule(jlm::util::FilePath(""), "", "");
  auto & rvsdg = rvsdgModule.Rvsdg();
 
  auto lambdaNode = jlm::rvsdg::LambdaNode::Create(
      rvsdg.GetRootRegion(),
      jlm::llvm::LlvmLambdaOperation::Create(
          functionType,
          "f",
          jlm::llvm::Linkage::externalLinkage));
 
  auto p = lambdaNode->GetFunctionArguments()[0];
  auto x = lambdaNode->GetFunctionArguments()[1];
 
  auto loopNode = LoopNode::create(lambdaNode->subregion());
 
  jlm::rvsdg::Output * buffer = nullptr;
  auto output0 = loopNode->AddLoopVar(p, &buffer);
  loopNode->AddLoopVar(x);
  loopNode->set_predicate(buffer);
 
  auto lambdaOutput = lambdaNode->finalize({ output0 });
 
  jlm::rvsdg::GraphExport::Create(*lambdaOutput, "f");
 
  // Act
  EliminateDeadNodes(rvsdgModule);
 
  // Assert
  EXPECT_EQ(loopNode->noutputs(), 1u);
  EXPECT_EQ(loopNode->ninputs(), 2u); // I believe that it actually should only have one input.
  // FIXME: The DNE seems to already be broken for a simple dead edge through it. It removes the
  // output from the loop node, but then seems to fail to remove the corresponding input, arguments,
  // and results.
}