llvm-project/mlir/lib/Transforms/Canonicalizer.cpp

//===- Canonicalizer.cpp - Canonicalize MLIR operations -------------------===//
//
// 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 transformation pass converts operations into their canonical forms by
// folding constants, applying operation identity transformations etc.
//
//===----------------------------------------------------------------------===//

#include "PassDetail.h"
#include "mlir/Pass/Pass.h"
#include "mlir/Transforms/GreedyPatternRewriteDriver.h"
#include "mlir/Transforms/Passes.h"

using namespace mlir;

namespace {
/// Canonicalize operations in nested regions.
struct Canonicalizer : public CanonicalizerBase<Canonicalizer> {
  /// Initialize the canonicalizer by building the set of patterns used during
  /// execution.
  void initialize(MLIRContext *context) override {
    OwningRewritePatternList owningPatterns;
    for (auto *op : context->getRegisteredOperations())
      op->getCanonicalizationPatterns(owningPatterns, context);
    patterns = std::move(owningPatterns);
  }
  void runOnOperation() override {
    applyPatternsAndFoldGreedily(getOperation()->getRegions(), patterns);
  }

  FrozenRewritePatternList patterns;
};
} // end anonymous namespace

/// Create a Canonicalizer pass.
std::unique_ptr<Pass> mlir::createCanonicalizerPass() {
  return std::make_unique<Canonicalizer>();
}