[flang-commits] [flang] [Flang][OpenMP] Accept the reduction modifier (PR #86492)

[Kiran Chandramohan via flang-commits]

https://github.com/kiranchandramohan created https://github.com/llvm/llvm-project/pull/86492

None

>From 9cb2b4fbaf528ee35cdb11896f7826f69a2de2a0 Mon Sep 17 00:00:00 2001
From: Kiran Chandramohan <kiran.chandramohan at arm.com>
Date: Mon, 25 Mar 2024 11:48:24 +0000
Subject: [PATCH] [Flang][OpenMP] Accept the reduction modifier

---
 flang/include/flang/Parser/dump-parse-tree.h  |  1 +
 flang/include/flang/Parser/parse-tree.h       |  3 ++-
 flang/lib/Parser/openmp-parsers.cpp           |  5 +++++
 flang/lib/Parser/unparse.cpp                  |  2 ++
 flang/lib/Semantics/check-omp-structure.cpp   |  2 +-
 .../test/Parser/OpenMP/reduction-modifier.f90 | 20 +++++++++++++++++++
 6 files changed, 31 insertions(+), 2 deletions(-)
 create mode 100644 flang/test/Parser/OpenMP/reduction-modifier.f90

diff --git a/flang/include/flang/Parser/dump-parse-tree.h b/flang/include/flang/Parser/dump-parse-tree.h
index b2c3d92909375c..c08f1be9331d18 100644
--- a/flang/include/flang/Parser/dump-parse-tree.h
+++ b/flang/include/flang/Parser/dump-parse-tree.h
@@ -541,6 +541,7 @@ class ParseTreeDumper {
   NODE_ENUM(OmpOrderModifier, Kind)
   NODE(parser, OmpProcBindClause)
   NODE_ENUM(OmpProcBindClause, Type)
+  NODE_ENUM(OmpReductionClause, ReductionModifier)
   NODE(parser, OmpReductionClause)
   NODE(parser, OmpInReductionClause)
   NODE(parser, OmpReductionCombiner)
diff --git a/flang/include/flang/Parser/parse-tree.h b/flang/include/flang/Parser/parse-tree.h
index c96abfba491d4b..93b08ad7453ee4 100644
--- a/flang/include/flang/Parser/parse-tree.h
+++ b/flang/include/flang/Parser/parse-tree.h
@@ -3549,7 +3549,8 @@ struct OmpReductionOperator {
 //                                         variable-name-list)
 struct OmpReductionClause {
   TUPLE_CLASS_BOILERPLATE(OmpReductionClause);
-  std::tuple<OmpReductionOperator, OmpObjectList> t;
+  ENUM_CLASS(ReductionModifier, Inscan, Task, Default)
+  std::tuple<std::optional<ReductionModifier>, OmpReductionOperator, OmpObjectList> t;
 };
 
 // OMP 5.0 2.19.5.6 in_reduction-clause -> IN_REDUCTION (reduction-identifier:
diff --git a/flang/lib/Parser/openmp-parsers.cpp b/flang/lib/Parser/openmp-parsers.cpp
index bba1be27158ce7..228ecba0a3308f 100644
--- a/flang/lib/Parser/openmp-parsers.cpp
+++ b/flang/lib/Parser/openmp-parsers.cpp
@@ -136,6 +136,11 @@ TYPE_PARSER(construct<OmpReductionOperator>(Parser<DefinedOperator>{}) ||
     construct<OmpReductionOperator>(Parser<ProcedureDesignator>{}))
 
 TYPE_PARSER(construct<OmpReductionClause>(
+    maybe(
+    ("INSCAN" >> pure(OmpReductionClause::ReductionModifier::Inscan) ||
+    "TASK" >> pure(OmpReductionClause::ReductionModifier::Task) ||
+        "DEFAULT" >> pure(OmpReductionClause::ReductionModifier::Default)) /
+    ","),
     Parser<OmpReductionOperator>{} / ":", Parser<OmpObjectList>{}))
 
 // OMP 5.0 2.19.5.6 IN_REDUCTION (reduction-identifier: variable-name-list)
diff --git a/flang/lib/Parser/unparse.cpp b/flang/lib/Parser/unparse.cpp
index baba4863f5775f..f56c6eac104e86 100644
--- a/flang/lib/Parser/unparse.cpp
+++ b/flang/lib/Parser/unparse.cpp
@@ -2086,6 +2086,7 @@ class UnparseVisitor {
     Walk(":", x.step);
   }
   void Unparse(const OmpReductionClause &x) {
+    Walk(std::get<std::optional<OmpReductionClause::ReductionModifier>>(x.t), ",");
     Walk(std::get<OmpReductionOperator>(x.t));
     Put(":");
     Walk(std::get<OmpObjectList>(x.t));
@@ -2723,6 +2724,7 @@ class UnparseVisitor {
   WALK_NESTED_ENUM(OmpScheduleClause, ScheduleType) // OMP schedule-type
   WALK_NESTED_ENUM(OmpDeviceClause, DeviceModifier) // OMP device modifier
   WALK_NESTED_ENUM(OmpDeviceTypeClause, Type) // OMP DEVICE_TYPE
+  WALK_NESTED_ENUM(OmpReductionClause, ReductionModifier) // OMP reduction-modifier
   WALK_NESTED_ENUM(OmpIfClause, DirectiveNameModifier) // OMP directive-modifier
   WALK_NESTED_ENUM(OmpCancelType, Type) // OMP cancel-type
   WALK_NESTED_ENUM(OmpOrderClause, Type) // OMP order-type
diff --git a/flang/lib/Semantics/check-omp-structure.cpp b/flang/lib/Semantics/check-omp-structure.cpp
index bf4debee1df34c..65f7036b93fb00 100644
--- a/flang/lib/Semantics/check-omp-structure.cpp
+++ b/flang/lib/Semantics/check-omp-structure.cpp
@@ -2289,7 +2289,7 @@ void OmpStructureChecker::Enter(const parser::OmpClause::Reduction &x) {
 bool OmpStructureChecker::CheckReductionOperators(
     const parser::OmpClause::Reduction &x) {
 
-  const auto &definedOp{std::get<0>(x.v.t)};
+  const auto &definedOp{std::get<1>(x.v.t)};
   bool ok = false;
   common::visit(
       common::visitors{
diff --git a/flang/test/Parser/OpenMP/reduction-modifier.f90 b/flang/test/Parser/OpenMP/reduction-modifier.f90
new file mode 100644
index 00000000000000..d46aa709595925
--- /dev/null
+++ b/flang/test/Parser/OpenMP/reduction-modifier.f90
@@ -0,0 +1,20 @@
+! RUN: %flang_fc1 -fdebug-unparse-no-sema -fopenmp %s | FileCheck --ignore-case %s
+! RUN: %flang_fc1 -fdebug-dump-parse-tree-no-sema -fopenmp %s | FileCheck --check-prefix="PARSE-TREE" %s
+
+subroutine foo()
+  integer :: i, j
+  j = 0
+! CHECK: !$OMP DO  REDUCTION(TASK,*:j)
+! PARSE-TREE: | | ExecutionPartConstruct -> ExecutableConstruct -> OpenMPConstruct -> OpenMPLoopConstruct
+! PARSE-TREE: | | | OmpBeginLoopDirective
+! PARSE-TREE: | | | | OmpLoopDirective -> llvm::omp::Directive = do
+! PARSE-TREE: | | | | OmpClauseList -> OmpClause -> Reduction -> OmpReductionClause
+! PARSE-TREE: | | | | | ReductionModifier = Task
+! PARSE-TREE: | | | | | OmpReductionOperator -> DefinedOperator -> IntrinsicOperator = Multiply
+! PARSE-TREE: | | | | | OmpObjectList -> OmpObject -> Designator -> DataRef -> Name = 'j
+  !$omp do reduction (task, *: j)
+  do i = 1, 10
+    j = j + 1
+  end do
+  !$omp end do
+end