func.walk([&](Operation *op) {
    if (op->getDialect() != tf_dialect) return;
    if (IsAllowListedOp(op)) return;
    if (op->hasAttr(kNoFallbackAttr)) {
      op->removeAttr(kNoFallbackAttr);
      return;
    }
    if (!ConvertToFlexOp(op)) signalPassFailure();
  });
}
}  // namespace internal

// Marks the op as no fallback.
def MarkNoFallback : NativeCodeCall<"SetNoFallbackAttr($_builder, $0)">;

def NoFallbackAttrNotSet : Constraint<CPred<
  "!$0.getDefiningOp()->hasAttr(kNoFallbackAttr)">>;

class FloatValueEquals<string val> : Constraint<CPred<
  "FloatValueEquals($0, " # val # ")">>;

class RankEquals<string rank> : Constraint<CPred<
  "RankEquals($0, " # rank # ")">>;