diff --git a/perf/cairo-perf-diff b/perf/cairo-perf-diff
index ebc8f55de..c9ce23f6c 100755
--- a/perf/cairo-perf-diff
+++ b/perf/cairo-perf-diff
@@ -49,7 +49,7 @@ END
 }
 
 # Yes, this ugly ad-hoc option parsing could be cleaned up
-if [ $# -eq 0 ] || [ "$1" = "--" ]; then
+if [ $# -eq 0 ] || [ "${1#-}" != "$1" ]; then
     usage
 fi