1//===- OptimizeArrayRepacking.cpp -----------------------------------------===//
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//===----------------------------------------------------------------------===//
10/// \file
11/// This pass removes redundant fir.pack_array operations, if it can prove
12/// that the source array is contiguous. In this case, it relink all uses
13/// of fir.pack_array result to the source. If such a rewrite happens,
14/// it may turn the using fir.unpack_array operation into one with the same
15/// temp and original operands - these are also removed as redundant.
16//===----------------------------------------------------------------------===//
17#include "flang/Optimizer/Builder/HLFIRTools.h"
18#include "flang/Optimizer/Dialect/FIRDialect.h"
19#include "flang/Optimizer/Dialect/FIROps.h"
20#include "flang/Optimizer/Support/Utils.h"
21#include "flang/Optimizer/Transforms/Passes.h"
22#include "mlir/Transforms/GreedyPatternRewriteDriver.h"
23
24namespace fir {
25#define GEN_PASS_DEF_OPTIMIZEARRAYREPACKING
26#include "flang/Optimizer/Transforms/Passes.h.inc"
27} // namespace fir
28
29namespace {
30class OptimizeArrayRepackingPass
31 : public fir::impl::OptimizeArrayRepackingBase<OptimizeArrayRepackingPass> {
32public:
33 void runOnOperation() override;
34};
35
36/// Relinks all uses of redundant fir.pack_array to the source.
37class PackingOfContiguous : public mlir::OpRewritePattern<fir::PackArrayOp> {
38public:
39 using OpRewritePattern::OpRewritePattern;
40 mlir::LogicalResult matchAndRewrite(fir::PackArrayOp,
41 mlir::PatternRewriter &) const override;
42};
43
44/// Erases fir.unpack_array with have the matching temp and original
45/// operands.
46class NoopUnpacking : public mlir::OpRewritePattern<fir::UnpackArrayOp> {
47public:
48 using OpRewritePattern::OpRewritePattern;
49 mlir::LogicalResult matchAndRewrite(fir::UnpackArrayOp,
50 mlir::PatternRewriter &) const override;
51};
52} // namespace
53
54mlir::LogicalResult
55PackingOfContiguous::matchAndRewrite(fir::PackArrayOp op,
56 mlir::PatternRewriter &rewriter) const {
57 mlir::Value box = op.getArray();
58 if (hlfir::isSimplyContiguous(box, !op.getInnermost())) {
59 rewriter.replaceAllUsesWith(op, box);
60 rewriter.eraseOp(op);
61 return mlir::success();
62 }
63 return mlir::failure();
64}
65
66mlir::LogicalResult
67NoopUnpacking::matchAndRewrite(fir::UnpackArrayOp op,
68 mlir::PatternRewriter &rewriter) const {
69 if (op.getTemp() == op.getOriginal()) {
70 rewriter.eraseOp(op);
71 return mlir::success();
72 }
73 return mlir::failure();
74}
75
76void OptimizeArrayRepackingPass::runOnOperation() {
77 mlir::func::FuncOp funcOp = getOperation();
78 mlir::MLIRContext *context = &getContext();
79 mlir::RewritePatternSet patterns(context);
80 mlir::GreedyRewriteConfig config;
81 config.setRegionSimplificationLevel(
82 mlir::GreedySimplifyRegionLevel::Disabled);
83 patterns.insert<PackingOfContiguous>(context);
84 patterns.insert<NoopUnpacking>(context);
85 if (mlir::failed(
86 mlir::applyPatternsGreedily(funcOp, std::move(patterns), config))) {
87 mlir::emitError(funcOp.getLoc(), "failure in array repacking optimization");
88 signalPassFailure();
89 }
90}
91

source code of flang/lib/Optimizer/Transforms/OptimizeArrayRepacking.cpp