flang/lib/Optimizer/Transforms/SimplifyRegionLite.cpp

   1 //===- SimplifyRegionLite.cpp -- region simplification lite ---------------===//
   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 #include "flang/Optimizer/Dialect/FIROps.h"
  10 #include "flang/Optimizer/Transforms/Passes.h"
  11 #include "mlir/IR/PatternMatch.h"
  12 #include "mlir/Pass/Pass.h"
  13 #include "mlir/Transforms/DialectConversion.h"
  14 #include "mlir/Transforms/GreedyPatternRewriteDriver.h"
  15 #include "mlir/Transforms/RegionUtils.h"
  16
  17 namespace fir {
  18 #define GEN_PASS_DEF_SIMPLIFYREGIONLITE
  19 #include "flang/Optimizer/Transforms/Passes.h.inc"
  20 } // namespace fir
  21
  22 namespace {
  23
  24 class SimplifyRegionLitePass
  25     : public fir::impl::SimplifyRegionLiteBase<SimplifyRegionLitePass> {
  26 public:
  27   void runOnOperation() override;
  28 };
  29
  30 class DummyRewriter : public mlir::PatternRewriter {
  31 public:
  32   DummyRewriter(mlir::MLIRContext *ctx) : mlir::PatternRewriter(ctx) {}
  33 };
  34
  35 } // namespace
  36
  37 void SimplifyRegionLitePass::runOnOperation() {
  38   auto op = getOperation();
  39   auto regions = op->getRegions();
  40   mlir::RewritePatternSet patterns(op.getContext());
  41   DummyRewriter rewriter(op.getContext());
  42   if (regions.empty())
  43     return;
  44
  45   (void)mlir::eraseUnreachableBlocks(rewriter, regions);
  46   (void)mlir::runRegionDCE(rewriter, regions);
  47 }
  48
  49 std::unique_ptr<mlir::Pass> fir::createSimplifyRegionLitePass() {
  50   return std::make_unique<SimplifyRegionLitePass>();
  51 }