1 files changed, 27 insertions, 4 deletions
diff --git a/flang/lib/Lower/OpenMP/ReductionProcessor.cpp b/flang/lib/Lower/OpenMP/ReductionProcessor.cpp
index 0d05ca5aee65..c1c94119fd90 100644
--- a/flang/lib/Lower/OpenMP/ReductionProcessor.cpp
+++ b/flang/lib/Lower/OpenMP/ReductionProcessor.cpp
@@ -13,6 +13,7 @@
 #include "ReductionProcessor.h"
 
 #include "flang/Lower/AbstractConverter.h"
+#include "flang/Lower/SymbolMap.h"
 #include "flang/Optimizer/Builder/HLFIRTools.h"
 #include "flang/Optimizer/Builder/Todo.h"
 #include "flang/Optimizer/Dialect/FIRType.h"
@@ -522,12 +523,20 @@ void ReductionProcessor::addDeclareReduction(
     if (reductionSymbols)
       reductionSymbols->push_back(symbol);
     mlir::Value symVal = converter.getSymbolAddress(*symbol);
-    auto redType = mlir::cast<fir::ReferenceType>(symVal.getType());
+    mlir::Type eleType;
+    auto refType = mlir::dyn_cast_or_null<fir::ReferenceType>(symVal.getType());
+    if (refType)
+      eleType = refType.getEleTy();
+    else
+      eleType = symVal.getType();
 
     // all arrays must be boxed so that we have convenient access to all the
     // information needed to iterate over the array
-    if (mlir::isa<fir::SequenceType>(redType.getEleTy())) {
-      hlfir::Entity entity{symVal};
+    if (mlir::isa<fir::SequenceType>(eleType)) {
+      // For Host associated symbols, use `SymbolBox` instead
+      Fortran::lower::SymbolBox symBox =
+          converter.lookupOneLevelUpSymbol(*symbol);
+      hlfir::Entity entity{symBox.getAddr()};
       entity = genVariableBox(currentLocation, builder, entity);
       mlir::Value box = entity.getBase();
 
@@ -538,11 +547,25 @@ void ReductionProcessor::addDeclareReduction(
       builder.create<fir::StoreOp>(currentLocation, box, alloca);
 
       symVal = alloca;
-      redType = mlir::cast<fir::ReferenceType>(symVal.getType());
+    } else if (mlir::isa<fir::BaseBoxType>(symVal.getType())) {
+      // boxed arrays are passed as values not by reference. Unfortunately,
+      // we can't pass a box by value to omp.redution_declare, so turn it
+      // into a reference
+
+      auto alloca =
+          builder.create<fir::AllocaOp>(currentLocation, symVal.getType());
+      builder.create<fir::StoreOp>(currentLocation, symVal, alloca);
+      symVal = alloca;
     } else if (auto declOp = symVal.getDefiningOp<hlfir::DeclareOp>()) {
       symVal = declOp.getBase();
     }
 
+    // this isn't the same as the by-val and by-ref passing later in the
+    // pipeline. Both styles assume that the variable is a reference at
+    // this point
+    assert(mlir::isa<fir::ReferenceType>(symVal.getType()) &&
+           "reduction input var is a reference");
+
     reductionVars.push_back(symVal);
   }
   const bool isByRef = doReductionByRef(reductionVars);