//===- TestSCFUtils.cpp --- Pass to test independent SCF dialect utils ----===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This file implements a pass to test SCF dialect utils.
//
//===----------------------------------------------------------------------===//

#include "mlir/Dialect/SCF/SCF.h"
#include "mlir/Dialect/SCF/Utils.h"
#include "mlir/IR/Builders.h"
#include "mlir/Pass/Pass.h"
#include "mlir/Transforms/Passes.h"

#include "llvm/ADT/SetVector.h"

using namespace mlir;

namespace {
class TestSCFUtilsPass : public PassWrapper<TestSCFUtilsPass, FunctionPass> {
public:
  explicit TestSCFUtilsPass() {}

  void runOnFunction() override {
    FuncOp func = getFunction();
    SmallVector<scf::ForOp, 4> toErase;

    func.walk([&](Operation *fakeRead) {
      if (fakeRead->getName().getStringRef() != "fake_read")
        return;
      auto *fakeCompute = fakeRead->getResult(0).use_begin()->getOwner();
      auto *fakeWrite = fakeCompute->getResult(0).use_begin()->getOwner();
      auto loop = fakeRead->getParentOfType<scf::ForOp>();

      OpBuilder b(loop);
      loop.moveOutOfLoop({fakeRead});
      fakeWrite->moveAfter(loop);
      auto newLoop = cloneWithNewYields(b, loop, fakeRead->getResult(0),
                                        fakeCompute->getResult(0));
      fakeCompute->getResult(0).replaceAllUsesWith(
          newLoop.getResults().take_back()[0]);
      toErase.push_back(loop);
    });
    for (auto loop : llvm::reverse(toErase))
      loop.erase();
  }
};
} // end namespace

namespace mlir {
void registerTestSCFUtilsPass() {
  PassRegistration<TestSCFUtilsPass>("test-scf-utils", "test scf utils");
}
} // namespace mlir