diff --git a/collects/tests/racket/unsafe.rktl b/collects/tests/racket/unsafe.rktl
index 49d4d359d3..16732fd689 100644
--- a/collects/tests/racket/unsafe.rktl
+++ b/collects/tests/racket/unsafe.rktl
@@ -92,6 +92,7 @@
   (test-bin 0 'unsafe-fxmodulo 0 -5)
   (test-bin 0 'unsafe-fxmodulo 10 1)
   (err/rt-test (unsafe-fxmodulo (error "bad") 1) exn:fail?) ; not 0
+  (err/rt-test (unsafe-fxmodulo 0 (error "bad")) exn:fail?) ; not 0
 
   (test-bin 3.4 'unsafe-fl+ 1.4 2.0)
   (test-bin -1.1 'unsafe-fl+ 1.0 -2.1)
diff --git a/src/racket/src/optimize.c b/src/racket/src/optimize.c
index 2efaa9ab69..b797fd1180 100644
--- a/src/racket/src/optimize.c
+++ b/src/racket/src/optimize.c
@@ -2642,7 +2642,7 @@ static Scheme_Object *finish_optimize_application3(Scheme_App3_Rec *app, Optimiz
         return app->rand1;
     } else if (IS_NAMED_PRIM(app->rator, "unsafe-fxremainder")
                || IS_NAMED_PRIM(app->rator, "unsafe-fxmodulo")) {
-      if (z1)
+      if (z1 && scheme_omittable_expr(app->rand2, 1, 20, 0, info, NULL, -1, 0))
         return scheme_make_integer(0);
       if (SAME_OBJ(app->rand2, scheme_make_integer(1))
           && scheme_omittable_expr(app->rand1, 1, 20, 0, info, NULL, -1, 0))