1 //===- Canonicalizer.cpp - Canonicalize MLIR operations -------------------===//
2 //
3 // Copyright 2019 The MLIR Authors.
4 //
5 // Licensed under the Apache License, Version 2.0 (the "License");
6 // you may not use this file except in compliance with the License.
7 // You may obtain a copy of the License at
8 //
9 //   http://www.apache.org/licenses/LICENSE-2.0
10 //
11 // Unless required by applicable law or agreed to in writing, software
12 // distributed under the License is distributed on an "AS IS" BASIS,
13 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 // See the License for the specific language governing permissions and
15 // limitations under the License.
16 // =============================================================================
17 //
18 // This transformation pass converts operations into their canonical forms by
19 // folding constants, applying operation identity transformations etc.
20 //
21 //===----------------------------------------------------------------------===//
22 
23 #include "mlir/IR/MLIRContext.h"
24 #include "mlir/IR/PatternMatch.h"
25 #include "mlir/Pass/Pass.h"
26 #include "mlir/Transforms/Passes.h"
27 using namespace mlir;
28 
29 namespace {
30 /// Canonicalize operations in nested regions.
31 struct Canonicalizer : public OperationPass<Canonicalizer> {
32   void runOnOperation() override {
33     OwningRewritePatternList patterns;
34 
35     // TODO: Instead of adding all known patterns from the whole system lazily
36     // add and cache the canonicalization patterns for ops we see in practice
37     // when building the worklist.  For now, we just grab everything.
38     auto *context = &getContext();
39     for (auto *op : context->getRegisteredOperations())
40       op->getCanonicalizationPatterns(patterns, context);
41 
42     Operation *op = getOperation();
43     applyPatternsGreedily(op->getRegions(), patterns);
44   }
45 };
46 } // end anonymous namespace
47 
48 /// Create a Canonicalizer pass.
49 std::unique_ptr<Pass> mlir::createCanonicalizerPass() {
50   return std::make_unique<Canonicalizer>();
51 }
52 
53 static PassRegistration<Canonicalizer> pass("canonicalize",
54                                             "Canonicalize operations");
55