diff --git a/mlir/include/mlir/Dialect/Affine/IR/AffineOps.h b/mlir/include/mlir/Dialect/Affine/IR/AffineOps.h
--- a/mlir/include/mlir/Dialect/Affine/IR/AffineOps.h
+++ b/mlir/include/mlir/Dialect/Affine/IR/AffineOps.h
@@ -32,6 +32,12 @@
 /// uses.
 bool isTopLevelValue(Value value);
 
+/// A utility function to check if a value is defined at the top level of
+/// `region` or is an argument of `region`. A value of index type defined at the
+/// top level of a `AffineScope` region is always a valid symbol for all
+/// uses in that region.
+bool isTopLevelValue(Value value, Region *region);
+
 /// Returns the closest region enclosing `op` that is held by an operation with
 /// trait `AffineScope`; `nullptr` if there is no such region.
 Region *getAffineScope(Operation *op);
diff --git a/mlir/lib/Dialect/Affine/IR/AffineOps.cpp b/mlir/lib/Dialect/Affine/IR/AffineOps.cpp
--- a/mlir/lib/Dialect/Affine/IR/AffineOps.cpp
+++ b/mlir/lib/Dialect/Affine/IR/AffineOps.cpp
@@ -33,7 +33,7 @@
 /// `region` or is an argument of `region`. A value of index type defined at the
 /// top level of a `AffineScope` region is always a valid symbol for all
 /// uses in that region.
-static bool isTopLevelValue(Value value, Region *region) {
+bool mlir::isTopLevelValue(Value value, Region *region) {
   if (auto arg = value.dyn_cast<BlockArgument>())
     return arg.getParentRegion() == region;
   return value.getDefiningOp()->getParentRegion() == region;