diff --git a/dlls/d3dx9_36/tests/math.c b/dlls/d3dx9_36/tests/math.c
index c9bf881deb3..7e00df853aa 100644
--- a/dlls/d3dx9_36/tests/math.c
+++ b/dlls/d3dx9_36/tests/math.c
@@ -2680,7 +2680,7 @@ static void test_D3DXSHEvalConeLight(void)
 
     dir.x = 1.1f; dir.y = 1.2f; dir.z = 2.76f;
 
-    for (l = 0; l < sizeof(test) / sizeof(test[0]); l++)
+    for (l = 0; l < ARRAY_SIZE(test); ++l)
     {
         for (order = D3DXSH_MINORDER; order <= D3DXSH_MAXORDER; order++)
         {