Index: sys/kern/subr_pctrie.c
===================================================================
--- sys/kern/subr_pctrie.c
+++ sys/kern/subr_pctrie.c
@@ -573,7 +573,7 @@
 				pred = node;
 			break;
 		}
-		if ((node->pn_popmap & ((1 << slot) - 1)) != 0)
+		if ((node->pn_popmap & -node->pn_popmap) >> slot == 0)
 			pred = node;
 		node = pctrie_node_load(&node->pn_child[slot], NULL,
 		    PCTRIE_LOCKED);
Index: sys/vm/vm_radix.c
===================================================================
--- sys/vm/vm_radix.c
+++ sys/vm/vm_radix.c
@@ -628,7 +628,7 @@
 				pred = rnode;
 			break;
 		}
-		if ((rnode->rn_popmap & ((1 << slot) - 1)) != 0)
+		if ((rnode->rn_popmap & -rnode->rn_popmap) >> slot == 0)
 			pred = rnode;
 		rnode = vm_radix_node_load(&rnode->rn_child[slot], LOCKED);
 	}