https://github.com/ergawy created
https://github.com/llvm/llvm-project/pull/150196
Backport 36c37b019b5daae79785e8558d693e6ec42b0ebd
Requested by @tblah
Fixes #149089 and #149700.
Before #145837, when processing a reduction symbol not yet supported by OpenMP
lowering, the reduction processor would simply skip filling in the reduction
symbols and variables. With #145837, this behvaior was slightly changed because
the reduction symbols are populated before invoking the reduction processor
(this is more convenient to shared the code with `do concurrent`).
This PR restores the previous behavior.
>From a1fb0285324db6ebb5c9bca3ed25dde3a70c4f16 Mon Sep 17 00:00:00 2001
From: Kareem Ergawy <kareem.erg...@amd.com>
Date: Wed, 23 Jul 2025 11:23:00 +0200
Subject: [PATCH] release/21.x: [flang][OpenMP] Restore reduction processor
behavior broken by #145837 (#150178)
Fixes #149089 and #149700.
Before #145837, when processing a reduction symbol not yet supported by
OpenMP lowering, the reduction processor would simply skip filling in
the reduction symbols and variables. With #145837, this behvaior was
slightly changed because the reduction symbols are populated before
invoking the reduction processor (this is more convenient to shared the
code with `do concurrent`).
This PR restores the previous behavior.
---
.../flang/Lower/Support/ReductionProcessor.h | 2 +-
flang/lib/Lower/Bridge.cpp | 3 +-
flang/lib/Lower/OpenMP/ClauseProcessor.cpp | 32 +++++++++++--------
.../lib/Lower/Support/ReductionProcessor.cpp | 12 ++++---
.../OpenMP/wsloop-reduction-non-intrinsic.f90 | 25 +++++++++++++++
5 files changed, 53 insertions(+), 21 deletions(-)
create mode 100644 flang/test/Lower/OpenMP/wsloop-reduction-non-intrinsic.f90
diff --git a/flang/include/flang/Lower/Support/ReductionProcessor.h
b/flang/include/flang/Lower/Support/ReductionProcessor.h
index 72d8a0096f511f..0b49049d43ed2e 100644
--- a/flang/include/flang/Lower/Support/ReductionProcessor.h
+++ b/flang/include/flang/Lower/Support/ReductionProcessor.h
@@ -124,7 +124,7 @@ class ReductionProcessor {
/// Creates a reduction declaration and associates it with an OpenMP block
/// directive.
template <typename OpType, typename RedOperatorListTy>
- static void processReductionArguments(
+ static bool processReductionArguments(
mlir::Location currentLocation, lower::AbstractConverter &converter,
const RedOperatorListTy &redOperatorList,
llvm::SmallVectorImpl<mlir::Value> &reductionVars,
diff --git a/flang/lib/Lower/Bridge.cpp b/flang/lib/Lower/Bridge.cpp
index 33c1f1e7a3c3ac..eeae24da267966 100644
--- a/flang/lib/Lower/Bridge.cpp
+++ b/flang/lib/Lower/Bridge.cpp
@@ -2123,9 +2123,10 @@ class FirConverter : public
Fortran::lower::AbstractConverter {
llvm::SmallVector<mlir::Value> reduceVars;
Fortran::lower::omp::ReductionProcessor rp;
- rp.processReductionArguments<fir::DeclareReductionOp>(
+ bool result = rp.processReductionArguments<fir::DeclareReductionOp>(
toLocation(), *this, info.reduceOperatorList, reduceVars,
reduceVarByRef, reductionDeclSymbols, info.reduceSymList);
+ assert(result && "Failed to process `do concurrent` reductions");
doConcurrentLoopOp.getReduceVarsMutable().assign(reduceVars);
doConcurrentLoopOp.setReduceSymsAttr(
diff --git a/flang/lib/Lower/OpenMP/ClauseProcessor.cpp
b/flang/lib/Lower/OpenMP/ClauseProcessor.cpp
index 74087d42a8e6e2..40f735c33cc3c1 100644
--- a/flang/lib/Lower/OpenMP/ClauseProcessor.cpp
+++ b/flang/lib/Lower/OpenMP/ClauseProcessor.cpp
@@ -1116,11 +1116,12 @@ bool ClauseProcessor::processInReduction(
collectReductionSyms(clause, inReductionSyms);
ReductionProcessor rp;
- rp.processReductionArguments<mlir::omp::DeclareReductionOp>(
- currentLocation, converter,
- std::get<typename omp::clause::ReductionOperatorList>(clause.t),
- inReductionVars, inReduceVarByRef, inReductionDeclSymbols,
- inReductionSyms);
+ if (!rp.processReductionArguments<mlir::omp::DeclareReductionOp>(
+ currentLocation, converter,
+ std::get<typename
omp::clause::ReductionOperatorList>(clause.t),
+ inReductionVars, inReduceVarByRef, inReductionDeclSymbols,
+ inReductionSyms))
+ inReductionSyms.clear();
// Copy local lists into the output.
llvm::copy(inReductionVars,
std::back_inserter(result.inReductionVars));
@@ -1461,10 +1462,12 @@ bool ClauseProcessor::processReduction(
}
ReductionProcessor rp;
- rp.processReductionArguments<mlir::omp::DeclareReductionOp>(
- currentLocation, converter,
- std::get<typename omp::clause::ReductionOperatorList>(clause.t),
- reductionVars, reduceVarByRef, reductionDeclSymbols,
reductionSyms);
+ if (!rp.processReductionArguments<mlir::omp::DeclareReductionOp>(
+ currentLocation, converter,
+ std::get<typename
omp::clause::ReductionOperatorList>(clause.t),
+ reductionVars, reduceVarByRef, reductionDeclSymbols,
+ reductionSyms))
+ reductionSyms.clear();
// Copy local lists into the output.
llvm::copy(reductionVars, std::back_inserter(result.reductionVars));
llvm::copy(reduceVarByRef, std::back_inserter(result.reductionByref));
@@ -1486,11 +1489,12 @@ bool ClauseProcessor::processTaskReduction(
collectReductionSyms(clause, taskReductionSyms);
ReductionProcessor rp;
- rp.processReductionArguments<mlir::omp::DeclareReductionOp>(
- currentLocation, converter,
- std::get<typename omp::clause::ReductionOperatorList>(clause.t),
- taskReductionVars, taskReduceVarByRef, taskReductionDeclSymbols,
- taskReductionSyms);
+ if (!rp.processReductionArguments<mlir::omp::DeclareReductionOp>(
+ currentLocation, converter,
+ std::get<typename
omp::clause::ReductionOperatorList>(clause.t),
+ taskReductionVars, taskReduceVarByRef,
taskReductionDeclSymbols,
+ taskReductionSyms))
+ taskReductionSyms.clear();
// Copy local lists into the output.
llvm::copy(taskReductionVars,
std::back_inserter(result.taskReductionVars));
diff --git a/flang/lib/Lower/Support/ReductionProcessor.cpp
b/flang/lib/Lower/Support/ReductionProcessor.cpp
index c0be1e229f8258..f58a103b03479f 100644
--- a/flang/lib/Lower/Support/ReductionProcessor.cpp
+++ b/flang/lib/Lower/Support/ReductionProcessor.cpp
@@ -39,7 +39,7 @@ namespace lower {
namespace omp {
// explicit template declarations
-template void ReductionProcessor::processReductionArguments<
+template bool ReductionProcessor::processReductionArguments<
mlir::omp::DeclareReductionOp, omp::clause::ReductionOperatorList>(
mlir::Location currentLocation, lower::AbstractConverter &converter,
const omp::clause::ReductionOperatorList &redOperatorList,
@@ -48,7 +48,7 @@ template void ReductionProcessor::processReductionArguments<
llvm::SmallVectorImpl<mlir::Attribute> &reductionDeclSymbols,
const llvm::SmallVectorImpl<const semantics::Symbol *> &reductionSymbols);
-template void ReductionProcessor::processReductionArguments<
+template bool ReductionProcessor::processReductionArguments<
fir::DeclareReductionOp, llvm::SmallVector<fir::ReduceOperationEnum>>(
mlir::Location currentLocation, lower::AbstractConverter &converter,
const llvm::SmallVector<fir::ReduceOperationEnum> &redOperatorList,
@@ -606,7 +606,7 @@ static bool doReductionByRef(mlir::Value reductionVar) {
}
template <typename OpType, typename RedOperatorListTy>
-void ReductionProcessor::processReductionArguments(
+bool ReductionProcessor::processReductionArguments(
mlir::Location currentLocation, lower::AbstractConverter &converter,
const RedOperatorListTy &redOperatorList,
llvm::SmallVectorImpl<mlir::Value> &reductionVars,
@@ -626,10 +626,10 @@ void ReductionProcessor::processReductionArguments(
std::get_if<omp::clause::ProcedureDesignator>(&redOperator.u)) {
if (!ReductionProcessor::supportedIntrinsicProcReduction(
*reductionIntrinsic)) {
- return;
+ return false;
}
} else {
- return;
+ return false;
}
}
}
@@ -764,6 +764,8 @@ void ReductionProcessor::processReductionArguments(
if (isDoConcurrent)
builder.restoreInsertionPoint(dcIP);
+
+ return true;
}
const semantics::SourceName
diff --git a/flang/test/Lower/OpenMP/wsloop-reduction-non-intrinsic.f90
b/flang/test/Lower/OpenMP/wsloop-reduction-non-intrinsic.f90
new file mode 100644
index 00000000000000..70b2ae1111a501
--- /dev/null
+++ b/flang/test/Lower/OpenMP/wsloop-reduction-non-intrinsic.f90
@@ -0,0 +1,25 @@
+! Tests reduction processor behavior when a reduction symbol is not supported.
+
+! RUN: %flang_fc1 -emit-hlfir -fopenmp -o - %s 2>&1 | FileCheck %s
+
+subroutine foo
+ implicit none
+ integer :: k, i
+
+ interface max
+ function max(m1,m2)
+ integer :: m1, m2
+ end function
+ end interface
+
+ !$omp do reduction (max: k)
+ do i=1,10
+ end do
+ !$omp end do
+end
+
+! Verify that unsupported reduction is ignored.
+! CHECK: omp.wsloop
+! CHECK-SAME: private(@{{[^[:space:]]+}} %{{[^[:space:]]+}}
+! CHECK-SAME: -> %{{[^[:space:]]+}} : !{{[^[:space:]]+}}) {
+! CHECK: }
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