diff --git a/lib/Dialect/mhlo/transforms/transform_unranked_hlo.cc b/lib/Dialect/mhlo/transforms/transform_unranked_hlo.cc
index 9325d7d..ded4ee3 100644
--- a/lib/Dialect/mhlo/transforms/transform_unranked_hlo.cc
+++ b/lib/Dialect/mhlo/transforms/transform_unranked_hlo.cc
@@ -58,7 +58,7 @@ namespace {
               sep fn(SinhOp) sep fn(TanOp)
 
 // TODO(herhut): Generate these out of op definitions.
-#define MAP_CHLO_OPERATION_CWISE_BINARY(fn, sep) fn(ZetaOp)
+#define MAP_CHLO_OPERATION_CWISE_BINARY(fn, sep) fn(PolygammaOp) sep fn(ZetaOp)
 
 template <typename OpTy>
 inline void AddLegalOpOnRankedTensor(ConversionTarget *target) {