diff --git a/test/crt-test.c b/test/crt-test.c
index 278d062..c3a6732 100644
--- a/test/crt-test.c
+++ b/test/crt-test.c
@@ -1476,19 +1476,13 @@ void test_math_trig() {
     TEST_FLT_ACCURACY(cos(2*F(3.141592654)), 1.0, 0.01); \
     TEST_FLT_NAN_ANY(cos(F(INFINITY))); \
     TEST_FLT_NAN_ANY(cos(F(-INFINITY))); \
-    TEST_FLT_NAN(cos(F(NAN)), F(NAN))
+    TEST_FLT_NAN(cos(F(NAN)), F(NAN)); \
+    TEST_FLT_NAN(cos(F(-NAN)), F(-NAN))
 
     TEST_COS(cos);
     TEST_COS(cosf);
     TEST_COS(cosl);
 
-#ifndef __OPTIMIZE__
-    // GCC and Clang break this test when optimizing.
-    TEST_FLT_NAN(cos(F(-NAN)), F(-NAN));
-    TEST_FLT_NAN(cosf(F(-NAN)), F(-NAN));
-    TEST_FLT_NAN(cosl(F(-NAN)), F(-NAN));
-#endif
-
 #define TEST_SIN(sin) \
     TEST_FLT_ACCURACY(sin(F(0.0)), 0.0, 0.01); \
     TEST_FLT_ACCURACY(sin(F(3.141592654)/2), 1.0, 0.01); \