1 | //===- PropagateFortranVariableAttributes.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 | /// \file |
9 | /// This file defines a pass that propagates FortranVariableFlagsAttr |
10 | /// attributes through HLFIR. For example, it can set contiguous attribute |
11 | /// on hlfir.designate that produces a contiguous slice of a contiguous |
12 | /// Fortran array. This pass can be applied multiple times to expose |
13 | /// more Fortran attributes, e.g. after inlining and constant propagation. |
14 | //===----------------------------------------------------------------------===// |
15 | |
16 | #include "flang/Optimizer/Builder/HLFIRTools.h" |
17 | #include "flang/Optimizer/Dialect/FIROpsSupport.h" |
18 | #include "flang/Optimizer/HLFIR/HLFIRDialect.h" |
19 | #include "flang/Optimizer/HLFIR/HLFIROps.h" |
20 | #include "flang/Optimizer/HLFIR/Passes.h" |
21 | #include "llvm/ADT/TypeSwitch.h" |
22 | |
23 | namespace hlfir { |
24 | #define GEN_PASS_DEF_PROPAGATEFORTRANVARIABLEATTRIBUTES |
25 | #include "flang/Optimizer/HLFIR/Passes.h.inc" |
26 | } // namespace hlfir |
27 | |
28 | #define DEBUG_TYPE "propagate-fortran-attrs" |
29 | |
30 | namespace { |
31 | class PropagateFortranVariableAttributes |
32 | : public hlfir::impl::PropagateFortranVariableAttributesBase< |
33 | PropagateFortranVariableAttributes> { |
34 | public: |
35 | using PropagateFortranVariableAttributesBase< |
36 | PropagateFortranVariableAttributes>:: |
37 | PropagateFortranVariableAttributesBase; |
38 | void runOnOperation() override; |
39 | }; |
40 | |
41 | class Propagator { |
42 | public: |
43 | void process(mlir::Operation *op); |
44 | |
45 | private: |
46 | static bool isContiguous(mlir::Operation *op) { |
47 | // Treat data allocations as contiguous, so that we can propagate |
48 | // the continuity from them. Allocations of fir.box must not be treated |
49 | // as contiguous. |
50 | if (mlir::isa<fir::AllocaOp, fir::AllocMemOp>(op) && |
51 | !mlir::isa<fir::BaseBoxType>( |
52 | fir::unwrapRefType(op->getResult(0).getType()))) |
53 | return true; |
54 | auto varOp = mlir::dyn_cast<fir::FortranVariableOpInterface>(op); |
55 | if (!varOp) |
56 | return false; |
57 | return hlfir::Entity{varOp}.isSimplyContiguous(); |
58 | } |
59 | |
60 | static void setContiguousAttr(fir::FortranVariableOpInterface op); |
61 | }; |
62 | } // namespace |
63 | |
64 | void Propagator::setContiguousAttr(fir::FortranVariableOpInterface op) { |
65 | LLVM_DEBUG(llvm::dbgs() << "Setting continuity for:\n" << op << "\n" ); |
66 | fir::FortranVariableFlagsEnum attrs = |
67 | op.getFortranAttrs().value_or(fir::FortranVariableFlagsEnum::None); |
68 | attrs = attrs | fir::FortranVariableFlagsEnum::contiguous; |
69 | op.setFortranAttrs(attrs); |
70 | } |
71 | |
72 | void Propagator::process(mlir::Operation *op) { |
73 | if (!isContiguous(op)) |
74 | return; |
75 | llvm::SmallVector<mlir::Operation *> workList{op}; |
76 | while (!workList.empty()) { |
77 | mlir::Operation *current = workList.pop_back_val(); |
78 | LLVM_DEBUG(llvm::dbgs() << "Propagating continuity from operation:\n" |
79 | << *current << "\n" ); |
80 | |
81 | for (mlir::OpOperand &use : current->getUses()) { |
82 | mlir::Operation *useOp = use.getOwner(); |
83 | if (auto varOp = mlir::dyn_cast<fir::FortranVariableOpInterface>(useOp)) { |
84 | // If the user is not currently contiguous, set the contiguous |
85 | // attribute and skip it. The propagation will pick it up later. |
86 | mlir::Value memref; |
87 | mlir::TypeSwitch<mlir::Operation *, void>(useOp) |
88 | .Case<hlfir::DeclareOp, hlfir::DesignateOp>( |
89 | [&](auto op) { memref = op.getMemref(); }) |
90 | .Default([&](auto op) {}); |
91 | |
92 | if (memref == use.get() && !isContiguous(varOp)) { |
93 | // Make additional checks for hlfir.designate. |
94 | if (auto designateOp = mlir::dyn_cast<hlfir::DesignateOp>(useOp)) |
95 | if (!hlfir::designatePreservesContinuity(designateOp)) |
96 | continue; |
97 | |
98 | setContiguousAttr(varOp); |
99 | } |
100 | continue; |
101 | } |
102 | mlir::TypeSwitch<mlir::Operation *, void>(useOp) |
103 | .Case( |
104 | [&](fir::ConvertOp op) { workList.push_back(op.getOperation()); }) |
105 | .Case([&](fir::EmboxOp op) { |
106 | if (op.getMemref() == use.get()) |
107 | workList.push_back(op.getOperation()); |
108 | }) |
109 | .Case([&](fir::ReboxOp op) { |
110 | if (op.getBox() == use.get() && fir::reboxPreservesContinuity(op)) |
111 | workList.push_back(op.getOperation()); |
112 | }); |
113 | } |
114 | } |
115 | } |
116 | |
117 | void PropagateFortranVariableAttributes::runOnOperation() { |
118 | mlir::Operation *rootOp = getOperation(); |
119 | mlir::MLIRContext *context = &getContext(); |
120 | mlir::RewritePatternSet patterns(context); |
121 | Propagator propagator; |
122 | rootOp->walk<mlir::WalkOrder::PreOrder>([&](mlir::Operation *op) { |
123 | propagator.process(op); |
124 | return mlir::WalkResult::advance(); |
125 | }); |
126 | } |
127 | |