mlir/lib/Reducer/OptReductionPass.cpp

   1 //===- OptReductionPass.cpp - Optimization Reduction Pass Wrapper ---------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file defines the Opt Reduction Pass Wrapper. It creates a MLIR pass to
  10 // run any optimization pass within it and only replaces the output module with
  11 // the transformed version if it is smaller and interesting.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "mlir/Pass/PassManager.h"
  16 #include "mlir/Pass/PassRegistry.h"
  17 #include "mlir/Reducer/Passes.h"
  18 #include "mlir/Reducer/Tester.h"
  19 #include "llvm/Support/Debug.h"
  20
  21 namespace mlir {
  22 #define GEN_PASS_DEF_OPTREDUCTION
  23 #include "mlir/Reducer/Passes.h.inc"
  24 } // namespace mlir
  25
  26 #define DEBUG_TYPE "mlir-reduce"
  27
  28 using namespace mlir;
  29
  30 namespace {
  31
  32 class OptReductionPass : public impl::OptReductionBase<OptReductionPass> {
  33 public:
  34   /// Runs the pass instance in the pass pipeline.
  35   void runOnOperation() override;
  36 };
  37
  38 } // namespace
  39
  40 /// Runs the pass instance in the pass pipeline.
  41 void OptReductionPass::runOnOperation() {
  42   LLVM_DEBUG(llvm::dbgs() << "\nOptimization Reduction pass: ");
  43
  44   Tester test(testerName, testerArgs);
  45
  46   ModuleOp module = this->getOperation();
  47   ModuleOp moduleVariant = module.clone();
  48
  49   OpPassManager passManager("builtin.module");
  50   if (failed(parsePassPipeline(optPass, passManager))) {
  51     module.emitError() << "\nfailed to parse pass pipeline";
  52     return signalPassFailure();
  53   }
  54
  55   std::pair<Tester::Interestingness, int> original = test.isInteresting(module);
  56   if (original.first != Tester::Interestingness::True) {
  57     module.emitError() << "\nthe original input is not interested";
  58     return signalPassFailure();
  59   }
  60
  61   // Temporarily push the variant under the main module and execute the pipeline
  62   // on it.
  63   module.getBody()->push_back(moduleVariant);
  64   LogicalResult pipelineResult = runPipeline(passManager, moduleVariant);
  65   moduleVariant->remove();
  66
  67   if (failed(pipelineResult)) {
  68     module.emitError() << "\nfailed to run pass pipeline";
  69     return signalPassFailure();
  70   }
  71
  72   std::pair<Tester::Interestingness, int> reduced =
  73       test.isInteresting(moduleVariant);
  74
  75   if (reduced.first == Tester::Interestingness::True &&
  76       reduced.second < original.second) {
  77     module.getBody()->clear();
  78     module.getBody()->getOperations().splice(
  79         module.getBody()->begin(), moduleVariant.getBody()->getOperations());
  80     LLVM_DEBUG(llvm::dbgs() << "\nSuccessful Transformed version\n\n");
  81   } else {
  82     LLVM_DEBUG(llvm::dbgs() << "\nUnsuccessful Transformed version\n\n");
  83   }
  84
  85   moduleVariant->destroy();
  86
  87   LLVM_DEBUG(llvm::dbgs() << "Pass Complete\n\n");
  88 }
  89
  90 std::unique_ptr<Pass> mlir::createOptReductionPass() {
  91   return std::make_unique<OptReductionPass>();
  92 }