diff --git a/Objects/setobject.c b/Objects/setobject.c
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -440,7 +440,7 @@
 {
     setentry *entry, *table;
     int table_is_malloced;
-    Py_ssize_t fill;
+    Py_ssize_t fill, used;
     setentry small_copy[PySet_MINSIZE];
 
 #ifdef Py_DEBUG
@@ -460,6 +460,7 @@
      * clearing.
      */
     fill = so->fill;
+    used = so->used;
     if (table_is_malloced)
         set_empty_to_minsize(so);
 
@@ -478,15 +479,14 @@
      * assert that the refcount on table is 1 now, i.e. that this function
      * has unique access to it, so decref side-effects can't alter it.
      */
-    for (entry = table; fill > 0; ++entry) {
+    for (entry = table; used > 0; ++entry) {
 #ifdef Py_DEBUG
         assert(i < n);
         ++i;
 #endif
-        if (entry->key) {
-            --fill;
-            if (entry->key != dummy)
-                Py_DECREF(entry->key);
+        if (entry->key && entry->key != dummy) {
+            used--;
+            Py_DECREF(entry->key);
         }
 #ifdef Py_DEBUG
         else