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[flang][OpenMP] Rewrite omp.loop to semantically equivalent ops
Introduces a new conversion pass that rewrites `omp.loop` ops to their semantically equivalent op nests bases on the surrounding/binding context of the `loop` op. Not all forms of `omp.loop` are supported yet.
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10 files changed

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lines changed

‎flang/include/flang/Common/OpenMP-utils.h

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@@ -0,0 +1,68 @@
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//===-- include/flang/Common/OpenMP-utils.h --------------------*- C++ -*-====//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef FORTRAN_COMMON_OPENMP_UTILS_H_
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#define FORTRAN_COMMON_OPENMP_UTILS_H_
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#include "flang/Semantics/symbol.h"
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14+
#include "mlir/IR/Builders.h"
15+
#include "mlir/IR/Value.h"
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17+
#include "llvm/ADT/ArrayRef.h"
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namespace Fortran::common::openmp {
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/// Structure holding the information needed to create and bind entry block
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/// arguments associated to a single clause.
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struct EntryBlockArgsEntry {
23+
llvm::ArrayRef<const Fortran::semantics::Symbol *> syms;
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llvm::ArrayRef<mlir::Value> vars;
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26+
bool isValid() const {
27+
// This check allows specifying a smaller number of symbols than values
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// because in some case cases a single symbol generates multiple block
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// arguments.
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return syms.size() <= vars.size();
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}
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};
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/// Structure holding the information needed to create and bind entry block
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/// arguments associated to all clauses that can define them.
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struct EntryBlockArgs {
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EntryBlockArgsEntry inReduction;
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EntryBlockArgsEntry map;
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EntryBlockArgsEntry priv;
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EntryBlockArgsEntry reduction;
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EntryBlockArgsEntry taskReduction;
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EntryBlockArgsEntry useDeviceAddr;
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EntryBlockArgsEntry useDevicePtr;
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bool isValid() const {
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return inReduction.isValid() && map.isValid() && priv.isValid() &&
47+
reduction.isValid() && taskReduction.isValid() &&
48+
useDeviceAddr.isValid() && useDevicePtr.isValid();
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}
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auto getSyms() const {
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return llvm::concat<const Fortran::semantics::Symbol *const>(
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inReduction.syms, map.syms, priv.syms, reduction.syms,
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taskReduction.syms, useDeviceAddr.syms, useDevicePtr.syms);
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}
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auto getVars() const {
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return llvm::concat<const mlir::Value>(inReduction.vars, map.vars,
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priv.vars, reduction.vars, taskReduction.vars, useDeviceAddr.vars,
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useDevicePtr.vars);
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}
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};
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mlir::Block *genEntryBlock(
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mlir::OpBuilder &builder, const EntryBlockArgs &args, mlir::Region &region);
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} // namespace Fortran::common::openmp
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#endif // FORTRAN_COMMON_OPENMP_UTILS_H_

‎flang/include/flang/Optimizer/OpenMP/Passes.td

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@@ -50,9 +50,30 @@ def FunctionFilteringPass : Pass<"omp-function-filtering"> {
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];
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}
5252

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5354
// Needs to be scheduled on Module as we create functions in it
5455
def LowerWorkshare : Pass<"lower-workshare", "::mlir::ModuleOp"> {
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let summary = "Lower workshare construct";
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}
5758

59+
def GenericLoopConversionPass
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: Pass<"omp-generic-loop-conversion", "mlir::func::FuncOp"> {
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let summary = "Converts OpenMP generic `omp.loop` to semantically "
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"equivalent OpenMP ops";
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let description = [{
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Rewrites `omp.loop` ops to their semantically equivalent nest of ops. The
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rewrite depends on the nesting/combination structure of the `loop` op
66+
within its surrounding context as well as its `bind` clause value.
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68+
We assume for now that all `omp.loop` ops will occur inside `FuncOp`'s. This
69+
will most likely remain the case in the future; even if, for example, we
70+
need a loop in copying data for a `firstprivate` variable, this loop will
71+
be nested in a constructor, an overloaded operator, or a runtime function.
72+
}];
73+
let dependentDialects = [
74+
"mlir::func::FuncDialect",
75+
"mlir::omp::OpenMPDialect"
76+
];
77+
}
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5879
#endif //FORTRAN_OPTIMIZER_OPENMP_PASSES

‎flang/lib/Common/CMakeLists.txt

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Original file line numberDiff line numberDiff line change
@@ -40,9 +40,13 @@ add_flang_library(FortranCommon
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default-kinds.cpp
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idioms.cpp
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LangOptions.cpp
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OpenMP-utils.cpp
4344
Version.cpp
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${version_inc}
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4647
LINK_COMPONENTS
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Support
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50+
LINK_LIBS
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MLIRIR
4852
)

‎flang/lib/Common/OpenMP-utils.cpp

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@@ -0,0 +1,47 @@
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//===-- include/flang/Common/OpenMP-utils.cpp ------------------*- C++ -*-====//
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//
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// 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+
//===----------------------------------------------------------------------===//
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9+
#include "flang/Common/OpenMP-utils.h"
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11+
#include "mlir/IR/OpDefinition.h"
12+
13+
namespace Fortran::common::openmp {
14+
mlir::Block *genEntryBlock(mlir::OpBuilder &builder, const EntryBlockArgs &args,
15+
mlir::Region &region) {
16+
assert(args.isValid() && "invalid args");
17+
assert(region.empty() && "non-empty region");
18+
19+
llvm::SmallVector<mlir::Type> types;
20+
llvm::SmallVector<mlir::Location> locs;
21+
unsigned numVars = args.inReduction.vars.size() + args.map.vars.size() +
22+
args.priv.vars.size() + args.reduction.vars.size() +
23+
args.taskReduction.vars.size() + args.useDeviceAddr.vars.size() +
24+
args.useDevicePtr.vars.size();
25+
types.reserve(numVars);
26+
locs.reserve(numVars);
27+
28+
auto extractTypeLoc = [&types, &locs](llvm::ArrayRef<mlir::Value> vals) {
29+
llvm::transform(vals, std::back_inserter(types),
30+
[](mlir::Value v) { return v.getType(); });
31+
llvm::transform(vals, std::back_inserter(locs),
32+
[](mlir::Value v) { return v.getLoc(); });
33+
};
34+
35+
// Populate block arguments in clause name alphabetical order to match
36+
// expected order by the BlockArgOpenMPOpInterface.
37+
extractTypeLoc(args.inReduction.vars);
38+
extractTypeLoc(args.map.vars);
39+
extractTypeLoc(args.priv.vars);
40+
extractTypeLoc(args.reduction.vars);
41+
extractTypeLoc(args.taskReduction.vars);
42+
extractTypeLoc(args.useDeviceAddr.vars);
43+
extractTypeLoc(args.useDevicePtr.vars);
44+
45+
return builder.createBlock(&region, {}, types, locs);
46+
}
47+
} // namespace Fortran::common::openmp

‎flang/lib/Lower/OpenMP/OpenMP.cpp

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@@ -19,6 +19,7 @@
1919
#include "DirectivesCommon.h"
2020
#include "ReductionProcessor.h"
2121
#include "Utils.h"
22+
#include "flang/Common/OpenMP-utils.h"
2223
#include "flang/Common/idioms.h"
2324
#include "flang/Lower/Bridge.h"
2425
#include "flang/Lower/ConvertExpr.h"
@@ -41,57 +42,12 @@
4142
#include "llvm/Frontend/OpenMP/OMPConstants.h"
4243

4344
using namespace Fortran::lower::omp;
45+
using namespace Fortran::common::openmp;
4446

4547
//===----------------------------------------------------------------------===//
4648
// Code generation helper functions
4749
//===----------------------------------------------------------------------===//
4850

49-
namespace {
50-
/// Structure holding the information needed to create and bind entry block
51-
/// arguments associated to a single clause.
52-
struct EntryBlockArgsEntry {
53-
llvm::ArrayRef<const semantics::Symbol *> syms;
54-
llvm::ArrayRef<mlir::Value> vars;
55-
56-
bool isValid() const {
57-
// This check allows specifying a smaller number of symbols than values
58-
// because in some case cases a single symbol generates multiple block
59-
// arguments.
60-
return syms.size() <= vars.size();
61-
}
62-
};
63-
64-
/// Structure holding the information needed to create and bind entry block
65-
/// arguments associated to all clauses that can define them.
66-
struct EntryBlockArgs {
67-
EntryBlockArgsEntry inReduction;
68-
EntryBlockArgsEntry map;
69-
EntryBlockArgsEntry priv;
70-
EntryBlockArgsEntry reduction;
71-
EntryBlockArgsEntry taskReduction;
72-
EntryBlockArgsEntry useDeviceAddr;
73-
EntryBlockArgsEntry useDevicePtr;
74-
75-
bool isValid() const {
76-
return inReduction.isValid() && map.isValid() && priv.isValid() &&
77-
reduction.isValid() && taskReduction.isValid() &&
78-
useDeviceAddr.isValid() && useDevicePtr.isValid();
79-
}
80-
81-
auto getSyms() const {
82-
return llvm::concat<const semantics::Symbol *const>(
83-
inReduction.syms, map.syms, priv.syms, reduction.syms,
84-
taskReduction.syms, useDeviceAddr.syms, useDevicePtr.syms);
85-
}
86-
87-
auto getVars() const {
88-
return llvm::concat<const mlir::Value>(
89-
inReduction.vars, map.vars, priv.vars, reduction.vars,
90-
taskReduction.vars, useDeviceAddr.vars, useDevicePtr.vars);
91-
}
92-
};
93-
} // namespace
94-
9551
static void genOMPDispatch(lower::AbstractConverter &converter,
9652
lower::SymMap &symTable,
9753
semantics::SemanticsContext &semaCtx,
@@ -623,50 +579,6 @@ static void genLoopVars(
623579
firOpBuilder.setInsertionPointAfter(storeOp);
624580
}
625581

626-
/// Create an entry block for the given region, including the clause-defined
627-
/// arguments specified.
628-
///
629-
/// \param [in] converter - PFT to MLIR conversion interface.
630-
/// \param [in] args - entry block arguments information for the given
631-
/// operation.
632-
/// \param [in] region - Empty region in which to create the entry block.
633-
static mlir::Block *genEntryBlock(lower::AbstractConverter &converter,
634-
const EntryBlockArgs &args,
635-
mlir::Region &region) {
636-
assert(args.isValid() && "invalid args");
637-
assert(region.empty() && "non-empty region");
638-
fir::FirOpBuilder &firOpBuilder = converter.getFirOpBuilder();
639-
640-
llvm::SmallVector<mlir::Type> types;
641-
llvm::SmallVector<mlir::Location> locs;
642-
unsigned numVars = args.inReduction.vars.size() + args.map.vars.size() +
643-
args.priv.vars.size() + args.reduction.vars.size() +
644-
args.taskReduction.vars.size() +
645-
args.useDeviceAddr.vars.size() +
646-
args.useDevicePtr.vars.size();
647-
types.reserve(numVars);
648-
locs.reserve(numVars);
649-
650-
auto extractTypeLoc = [&types, &locs](llvm::ArrayRef<mlir::Value> vals) {
651-
llvm::transform(vals, std::back_inserter(types),
652-
[](mlir::Value v) { return v.getType(); });
653-
llvm::transform(vals, std::back_inserter(locs),
654-
[](mlir::Value v) { return v.getLoc(); });
655-
};
656-
657-
// Populate block arguments in clause name alphabetical order to match
658-
// expected order by the BlockArgOpenMPOpInterface.
659-
extractTypeLoc(args.inReduction.vars);
660-
extractTypeLoc(args.map.vars);
661-
extractTypeLoc(args.priv.vars);
662-
extractTypeLoc(args.reduction.vars);
663-
extractTypeLoc(args.taskReduction.vars);
664-
extractTypeLoc(args.useDeviceAddr.vars);
665-
extractTypeLoc(args.useDevicePtr.vars);
666-
667-
return firOpBuilder.createBlock(&region, {}, types, locs);
668-
}
669-
670582
static void
671583
markDeclareTarget(mlir::Operation *op, lower::AbstractConverter &converter,
672584
mlir::omp::DeclareTargetCaptureClause captureClause,
@@ -919,7 +831,7 @@ static void genBodyOfTargetDataOp(
919831
ConstructQueue::const_iterator item) {
920832
fir::FirOpBuilder &firOpBuilder = converter.getFirOpBuilder();
921833

922-
genEntryBlock(converter, args, dataOp.getRegion());
834+
genEntryBlock(firOpBuilder, args, dataOp.getRegion());
923835
bindEntryBlockArgs(converter, dataOp, args);
924836

925837
// Insert dummy instruction to remember the insertion position. The
@@ -996,7 +908,7 @@ static void genBodyOfTargetOp(
996908
auto argIface = llvm::cast<mlir::omp::BlockArgOpenMPOpInterface>(*targetOp);
997909

998910
mlir::Region &region = targetOp.getRegion();
999-
mlir::Block *entryBlock = genEntryBlock(converter, args, region);
911+
mlir::Block *entryBlock = genEntryBlock(firOpBuilder, args, region);
1000912
bindEntryBlockArgs(converter, targetOp, args);
1001913

1002914
// Check if cloning the bounds introduced any dependency on the outer region.
@@ -1122,7 +1034,7 @@ static OpTy genWrapperOp(lower::AbstractConverter &converter,
11221034
auto op = firOpBuilder.create<OpTy>(loc, clauseOps);
11231035

11241036
// Create entry block with arguments.
1125-
genEntryBlock(converter, args, op.getRegion());
1037+
genEntryBlock(firOpBuilder, args, op.getRegion());
11261038

11271039
return op;
11281040
}
@@ -1588,7 +1500,7 @@ genParallelOp(lower::AbstractConverter &converter, lower::SymMap &symTable,
15881500
const EntryBlockArgs &args, DataSharingProcessor *dsp,
15891501
bool isComposite = false) {
15901502
auto genRegionEntryCB = [&](mlir::Operation *op) {
1591-
genEntryBlock(converter, args, op->getRegion(0));
1503+
genEntryBlock(converter.getFirOpBuilder(), args, op->getRegion(0));
15921504
bindEntryBlockArgs(
15931505
converter, llvm::cast<mlir::omp::BlockArgOpenMPOpInterface>(op), args);
15941506
return llvm::to_vector(args.getSyms());
@@ -1661,12 +1573,12 @@ genSectionsOp(lower::AbstractConverter &converter, lower::SymMap &symTable,
16611573
args.reduction.syms = reductionSyms;
16621574
args.reduction.vars = clauseOps.reductionVars;
16631575

1664-
genEntryBlock(converter, args, sectionsOp.getRegion());
1576+
genEntryBlock(builder, args, sectionsOp.getRegion());
16651577
mlir::Operation *terminator =
16661578
lower::genOpenMPTerminator(builder, sectionsOp, loc);
16671579

16681580
auto genRegionEntryCB = [&](mlir::Operation *op) {
1669-
genEntryBlock(converter, args, op->getRegion(0));
1581+
genEntryBlock(builder, args, op->getRegion(0));
16701582
bindEntryBlockArgs(
16711583
converter, llvm::cast<mlir::omp::BlockArgOpenMPOpInterface>(op), args);
16721584
return llvm::to_vector(args.getSyms());
@@ -1989,7 +1901,7 @@ genTaskOp(lower::AbstractConverter &converter, lower::SymMap &symTable,
19891901
taskArgs.priv.vars = clauseOps.privateVars;
19901902

19911903
auto genRegionEntryCB = [&](mlir::Operation *op) {
1992-
genEntryBlock(converter, taskArgs, op->getRegion(0));
1904+
genEntryBlock(converter.getFirOpBuilder(), taskArgs, op->getRegion(0));
19931905
bindEntryBlockArgs(converter,
19941906
llvm::cast<mlir::omp::BlockArgOpenMPOpInterface>(op),
19951907
taskArgs);

‎flang/lib/Optimizer/OpenMP/CMakeLists.txt

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2,6 +2,7 @@ get_property(dialect_libs GLOBAL PROPERTY MLIR_DIALECT_LIBS)
22

33
add_flang_library(FlangOpenMPTransforms
44
FunctionFiltering.cpp
5+
GenericLoopConversion.cpp
56
MapsForPrivatizedSymbols.cpp
67
MapInfoFinalization.cpp
78
MarkDeclareTarget.cpp
@@ -25,4 +26,5 @@ add_flang_library(FlangOpenMPTransforms
2526
HLFIRDialect
2627
MLIRIR
2728
MLIRPass
29+
MLIRTransformUtils
2830
)

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