else if (!strcmp(arg, "--cached") ||
                                 !strcmp(arg, "--staged")) {
                                add_head_to_pending(&rev);
-                               if (!rev.pending.nr)
-                                       die("No HEAD commit to compare with (yet)");
+                               if (!rev.pending.nr) {
+                                       struct tree *tree;
+                                       tree = lookup_tree((const unsigned char*)EMPTY_TREE_SHA1_BIN);
+                                       add_pending_object(&rev, &tree->object, "HEAD");
+                               }
                                break;
                        }
                }