diff --git a/src/Compat.php b/src/Compat.php
index c5b2cdd3..8e013903 100644
--- a/src/Compat.php
+++ b/src/Compat.php
@@ -2782,7 +2782,8 @@ public static function runtime_speed_test($iterations, $maxTimeout)
             $a->mulInt64($b);
         }
         $end = microtime(true);
-        $diff = ceil(($end - $start) * 1000);
+        /** @var int $diff */
+        $diff = (int) ceil(($end - $start) * 1000);
         return $diff < $maxTimeout;
     }