diff --git a/shell-completion/zsh/_systemctl.in b/shell-completion/zsh/_systemctl.in
index 98b4d2eb65..5a6e7d391d 100644
--- a/shell-completion/zsh/_systemctl.in
+++ b/shell-completion/zsh/_systemctl.in
@@ -161,8 +161,7 @@ __systemctl()
 (( $+functions[_systemctl_all_units] )) ||
     _systemctl_all_units()
 {
-    if ( [[ ${+_sys_all_units} -eq 0 ]] || _cache_invalid SYS_ALL_UNITS$_sys_service_mgr ) ||
-           ! _retrieve_cache SYS_ALL_UNITS$_sys_service_mgr;
+    if _cache_invalid SYS_ALL_UNITS$_sys_service_mgr || ! _retrieve_cache SYS_ALL_UNITS$_sys_service_mgr;
     then
         _sys_all_units=( ${${(f)"$(__systemctl list-units --all)"}%% *} )
         _store_cache SYS_ALL_UNITS$_sys_service_mgr _sys_all_units
@@ -175,8 +174,7 @@ __systemctl()
 {
     local -a all_unit_files;
     local -a really_all_units;
-    if ( [[ ${+_sys_really_all_units} -eq 0 ]] || _cache_invalid SYS_REALLY_ALL_UNITS$_sys_service_mgr ) ||
-           ! _retrieve_cache SYS_REALLY_ALL_UNITS$_sys_service_mgr;
+    if _cache_invalid SYS_REALLY_ALL_UNITS$_sys_service_mgr || ! _retrieve_cache SYS_REALLY_ALL_UNITS$_sys_service_mgr;
     then
         all_unit_files=( ${${(f)"$(__systemctl list-unit-files)"}%% *} )
         _systemctl_all_units