diff --git a/optimizer.go b/optimizer.go
index 36d4553..03410f0 100644
--- a/optimizer.go
+++ b/optimizer.go
@@ -403,7 +403,7 @@ func getTransformArgIdxForOptimization(funcName string, args []Expr) int {
 
 func isLabelManipulationFunc(funcName string) bool {
 	switch strings.ToLower(funcName) {
-	case "alias", "label_copy", "label_del", "label_graphite_group", "label_join", "label_keep", "label_lowercase",
+	case "alias", "drop_common_labels", "label_copy", "label_del", "label_graphite_group", "label_join", "label_keep", "label_lowercase",
 		"label_map", "label_match", "label_mismatch", "label_move", "label_replace", "label_set", "label_transform",
 		"label_uppercase", "label_value":
 		return true
diff --git a/transform.go b/transform.go
index b0bdc25..865c68e 100644
--- a/transform.go
+++ b/transform.go
@@ -28,6 +28,7 @@ var transformFuncs = map[string]bool{
 	"day_of_week":          true,
 	"days_in_month":        true,
 	"deg":                  true,
+	"drop_common_labels":   true,
 	"end":                  true,
 	"exp":                  true,
 	"floor":                true,