[flang][NFC] move extractSequenceType helper out of OpenACC to share code (#84957)

Moving extractSequenceType to FIRType.h so that this can also be used
from OpenMP.

OpenMP array reductions 5/6
Previous PR: #84955
Next PR: #84958

Author: tblah

flang/include/flang/Optimizer/Dialect/FIRType.h

@@ -237,6 +237,9 @@ inline mlir::Type unwrapSequenceType(mlir::Type t) {
   return t;
 }
 
+/// Return the nested sequence type if any.
+mlir::Type extractSequenceType(mlir::Type ty);
+
 inline mlir::Type unwrapRefType(mlir::Type t) {
   if (auto eleTy = dyn_cast_ptrEleTy(t))
     return eleTy;

flang/lib/Lower/OpenACC.cpp

@@ -406,19 +406,6 @@ fir::ShapeOp genShapeOp(mlir::OpBuilder &builder, fir::SequenceType seqTy,
   return builder.create<fir::ShapeOp>(loc, extents);
 }
 
-/// Return the nested sequence type if any.
-static mlir::Type extractSequenceType(mlir::Type ty) {
-  if (mlir::isa<fir::SequenceType>(ty))
-    return ty;
-  if (auto boxTy = mlir::dyn_cast<fir::BaseBoxType>(ty))
-    return extractSequenceType(boxTy.getEleTy());
-  if (auto heapTy = mlir::dyn_cast<fir::HeapType>(ty))
-    return extractSequenceType(heapTy.getEleTy());
-  if (auto ptrTy = mlir::dyn_cast<fir::PointerType>(ty))
-    return extractSequenceType(ptrTy.getEleTy());
-  return mlir::Type{};
-}
-
 template <typename RecipeOp>
 static void genPrivateLikeInitRegion(mlir::OpBuilder &builder, RecipeOp recipe,
                                      mlir::Type ty, mlir::Location loc) {
@@ -454,7 +441,7 @@ static void genPrivateLikeInitRegion(mlir::OpBuilder &builder, RecipeOp recipe,
       }
     }
   } else if (auto boxTy = mlir::dyn_cast_or_null<fir::BaseBoxType>(ty)) {
-    mlir::Type innerTy = extractSequenceType(boxTy);
+    mlir::Type innerTy = fir::extractSequenceType(boxTy);
     if (!innerTy)
       TODO(loc, "Unsupported boxed type in OpenACC privatization");
     fir::FirOpBuilder firBuilder{builder, recipe.getOperation()};
@@ -688,7 +675,7 @@ mlir::acc::FirstprivateRecipeOp Fortran::lower::createOrGetFirstprivateRecipe(
   } else if (auto boxTy = mlir::dyn_cast_or_null<fir::BaseBoxType>(ty)) {
     fir::FirOpBuilder firBuilder{builder, recipe.getOperation()};
     llvm::SmallVector<mlir::Value> tripletArgs;
-    mlir::Type innerTy = extractSequenceType(boxTy);
+    mlir::Type innerTy = fir::extractSequenceType(boxTy);
     fir::SequenceType seqTy =
         mlir::dyn_cast_or_null<fir::SequenceType>(innerTy);
     if (!seqTy)
@@ -1018,7 +1005,7 @@ static mlir::Value genReductionInitRegion(fir::FirOpBuilder &builder,
       return declareOp.getBase();
     }
   } else if (auto boxTy = mlir::dyn_cast_or_null<fir::BaseBoxType>(ty)) {
-    mlir::Type innerTy = extractSequenceType(boxTy);
+    mlir::Type innerTy = fir::extractSequenceType(boxTy);
     if (!mlir::isa<fir::SequenceType>(innerTy))
       TODO(loc, "Unsupported boxed type for reduction");
     // Create the private copy from the initial fir.box.
@@ -1230,7 +1217,7 @@ static void genCombiner(fir::FirOpBuilder &builder, mlir::Location loc,
     builder.create<fir::StoreOp>(loc, res, addr1);
     builder.setInsertionPointAfter(loops[0]);
   } else if (auto boxTy = mlir::dyn_cast<fir::BaseBoxType>(ty)) {
-    mlir::Type innerTy = extractSequenceType(boxTy);
+    mlir::Type innerTy = fir::extractSequenceType(boxTy);
     fir::SequenceType seqTy =
         mlir::dyn_cast_or_null<fir::SequenceType>(innerTy);
     if (!seqTy)

flang/lib/Optimizer/Dialect/FIRType.cpp

@@ -254,6 +254,18 @@ bool hasDynamicSize(mlir::Type t) {
   return false;
 }
 
+mlir::Type extractSequenceType(mlir::Type ty) {
+  if (mlir::isa<fir::SequenceType>(ty))
+    return ty;
+  if (auto boxTy = mlir::dyn_cast<fir::BaseBoxType>(ty))
+    return extractSequenceType(boxTy.getEleTy());
+  if (auto heapTy = mlir::dyn_cast<fir::HeapType>(ty))
+    return extractSequenceType(heapTy.getEleTy());
+  if (auto ptrTy = mlir::dyn_cast<fir::PointerType>(ty))
+    return extractSequenceType(ptrTy.getEleTy());
+  return mlir::Type{};
+}
+
 bool isPointerType(mlir::Type ty) {
   if (auto refTy = fir::dyn_cast_ptrEleTy(ty))
     ty = refTy;