diff --git a/mlir/lib/Dialect/SparseTensor/Transforms/CodegenUtils.cpp b/mlir/lib/Dialect/SparseTensor/Transforms/CodegenUtils.cpp
--- a/mlir/lib/Dialect/SparseTensor/Transforms/CodegenUtils.cpp
+++ b/mlir/lib/Dialect/SparseTensor/Transforms/CodegenUtils.cpp
@@ -172,6 +172,7 @@
         case SparseTensorFieldKind::ValMemRef:
           return callback(valMemType, fieldIdx, fieldKind, dim, dlt);
         };
+        llvm_unreachable("unrecognized field type");
       });
 }