[flang][OpenMP] Try to unify induction var privatization for OMP regions.

flang/lib/Lower/OpenMP/DataSharingProcessor.cpp

@@ -422,8 +422,9 @@ void DataSharingProcessor::collectImplicitSymbols() {
 }
 
 void DataSharingProcessor::collectPreDeterminedSymbols() {
-  collectSymbols(Fortran::semantics::Symbol::Flag::OmpPreDetermined,
-                 preDeterminedSymbols);
+  if (shouldCollectPreDeterminedSymbols)
+    collectSymbols(Fortran::semantics::Symbol::Flag::OmpPreDetermined,
+                   preDeterminedSymbols);
 }
 
 void DataSharingProcessor::privatize(

flang/lib/Lower/OpenMP/DataSharingProcessor.h

@@ -51,6 +51,7 @@ class DataSharingProcessor {
   fir::FirOpBuilder &firOpBuilder;
   omp::List<omp::Clause> clauses;
   Fortran::lower::pft::Evaluation &eval;
+  bool shouldCollectPreDeterminedSymbols;
   bool useDelayedPrivatization;
   Fortran::lower::SymMap *symTable;
 
@@ -99,10 +100,12 @@ class DataSharingProcessor {
                        Fortran::semantics::SemanticsContext &semaCtx,
                        const List<Clause> &clauses,
                        Fortran::lower::pft::Evaluation &eval,
+                       bool shouldCollectPreDeterminedSymbols,
                        bool useDelayedPrivatization = false,
                        Fortran::lower::SymMap *symTable = nullptr)
       : hasLastPrivateOp(false), converter(converter), semaCtx(semaCtx),
         firOpBuilder(converter.getFirOpBuilder()), clauses(clauses), eval(eval),
+        shouldCollectPreDeterminedSymbols(shouldCollectPreDeterminedSymbols),
         useDelayedPrivatization(useDelayedPrivatization), symTable(symTable) {}
 
   // Privatisation is split into two steps.

flang/lib/Lower/OpenMP/Decomposer.cpp

@@ -123,4 +123,9 @@ ConstructQueue buildConstructQueue(
 
   return constructs;
 }
+
+bool isLastItemInQueue(ConstructQueue::iterator item,
+                       const ConstructQueue &queue) {
+  return std::prev(queue.end()) == item;
+}
 } // namespace Fortran::lower::omp

flang/lib/Lower/OpenMP/Decomposer.h

@@ -46,6 +46,9 @@ ConstructQueue buildConstructQueue(mlir::ModuleOp modOp,
                                    const parser::CharBlock &source,
                                    llvm::omp::Directive compound,
                                    const List<Clause> &clauses);
+
+bool isLastItemInQueue(ConstructQueue::iterator item,
+                       const ConstructQueue &queue);
 } // namespace Fortran::lower::omp
 
 #endif // FORTRAN_LOWER_OPENMP_DECOMPOSER_H

flang/lib/Lower/OpenMP/OpenMP.cpp

@@ -593,7 +593,8 @@ static void createBodyOfOp(mlir::Operation &op, const OpWithBodyGenInfo &info,
   std::optional<DataSharingProcessor> tempDsp;
   if (privatize) {
     if (!info.dsp) {
-      tempDsp.emplace(info.converter, info.semaCtx, *info.clauses, info.eval);
+      tempDsp.emplace(info.converter, info.semaCtx, *info.clauses, info.eval,
+                      Fortran::lower::omp::isLastItemInQueue(item, queue));
       tempDsp->processStep1();
     }
   }
@@ -1361,6 +1362,7 @@ genParallelOp(Fortran::lower::AbstractConverter &converter,
 
   bool privatize = !outerCombined;
   DataSharingProcessor dsp(converter, semaCtx, clauses, eval,
+                           Fortran::lower::omp::isLastItemInQueue(item, queue),
                            /*useDelayedPrivatization=*/true, &symTable);
 
   if (privatize)
@@ -1438,7 +1440,8 @@ genSectionsOp(Fortran::lower::AbstractConverter &converter,
 
   // Insert privatizations before SECTIONS
   symTable.pushScope();
-  DataSharingProcessor dsp(converter, semaCtx, clauses, eval);
+  DataSharingProcessor dsp(converter, semaCtx, clauses, eval,
+                           Fortran::lower::omp::isLastItemInQueue(item, queue));
   dsp.processStep1();
 
   List<Clause> nonDsaClauses;
@@ -1511,7 +1514,8 @@ genSimdOp(Fortran::lower::AbstractConverter &converter,
           ConstructQueue::iterator item) {
   fir::FirOpBuilder &firOpBuilder = converter.getFirOpBuilder();
   symTable.pushScope();
-  DataSharingProcessor dsp(converter, semaCtx, clauses, eval);
+  DataSharingProcessor dsp(converter, semaCtx, clauses, eval,
+                           Fortran::lower::omp::isLastItemInQueue(item, queue));
   dsp.processStep1();
 
   Fortran::lower::StatementContext stmtCtx;
@@ -1835,7 +1839,8 @@ genWsloopOp(Fortran::lower::AbstractConverter &converter,
             ConstructQueue::iterator item) {
   fir::FirOpBuilder &firOpBuilder = converter.getFirOpBuilder();
   symTable.pushScope();
-  DataSharingProcessor dsp(converter, semaCtx, clauses, eval);
+  DataSharingProcessor dsp(converter, semaCtx, clauses, eval,
+                           Fortran::lower::omp::isLastItemInQueue(item, queue));
   dsp.processStep1();
 
   Fortran::lower::StatementContext stmtCtx;