diff --git a/cache.h b/cache.h
index 1bf2d4bde6..770d8bc950 100644
--- a/cache.h
+++ b/cache.h
@@ -445,6 +445,7 @@ extern int add_index_entry(struct index_state *, struct cache_entry *ce, int opt
 extern struct cache_entry *refresh_cache_entry(struct cache_entry *ce, int really);
 extern void rename_index_entry_at(struct index_state *, int pos, const char *new_name);
 extern int remove_index_entry_at(struct index_state *, int pos);
+extern void remove_marked_cache_entries(struct index_state *istate);
 extern int remove_file_from_index(struct index_state *, const char *path);
 #define ADD_CACHE_VERBOSE 1
 #define ADD_CACHE_PRETEND 2
diff --git a/read-cache.c b/read-cache.c
index 940ec76fdf..59a274b464 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -443,6 +443,26 @@ int remove_index_entry_at(struct index_state *istate, int pos)
 	return 1;
 }
 
+/*
+ * Remove all cache ententries marked for removal, that is where
+ * CE_REMOVE is set in ce_flags.  This is much more effective than
+ * calling remove_index_entry_at() for each entry to be removed.
+ */
+void remove_marked_cache_entries(struct index_state *istate)
+{
+	struct cache_entry **ce_array = istate->cache;
+	unsigned int i, j;
+
+	for (i = j = 0; i < istate->cache_nr; i++) {
+		if (ce_array[i]->ce_flags & CE_REMOVE)
+			remove_name_hash(ce_array[i]);
+		else
+			ce_array[j++] = ce_array[i];
+	}
+	istate->cache_changed = 1;
+	istate->cache_nr = j;
+}
+
 int remove_file_from_index(struct index_state *istate, const char *path)
 {
 	int pos = index_name_pos(istate, path, strlen(path));
diff --git a/unpack-trees.c b/unpack-trees.c
index e3c3fa12aa..273b5da0a2 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -93,11 +93,9 @@ static int check_updates(struct unpack_trees_options *o)
 			display_progress(progress, ++cnt);
 			if (o->update)
 				unlink_entry(ce);
-			remove_index_entry_at(&o->result, i);
-			i--;
-			continue;
 		}
 	}
+	remove_marked_cache_entries(&o->result);
 	remove_scheduled_dirs();
 
 	for (i = 0; i < index->cache_nr; i++) {