diff --git a/dlls/d3dx9_36/tests/mesh.c b/dlls/d3dx9_36/tests/mesh.c
index 54ef66b..8a87da3 100644
--- a/dlls/d3dx9_36/tests/mesh.c
+++ b/dlls/d3dx9_36/tests/mesh.c
@@ -4783,6 +4783,9 @@ static void test_create_skin_info(void)
             DWORD num_influences;
             DWORD exp_vertices[2];
             FLOAT exp_weights[2];
+            float nan_value;
+
+            memset(&nan_value, 0xff, sizeof(nan_value));
 
             /* vertex and weight arrays untouched when num_influences is 0 */
             vertices[0] = 0xdeadbeef;
@@ -4809,7 +4812,7 @@ static void test_create_skin_info(void)
             exp_vertices[0] = 0;
             exp_vertices[1] = 0x87654321;
             exp_weights[0] = 0.5;
-            exp_weights[1] = 0.0f / 0.0f;
+            exp_weights[1] = nan_value;
             num_influences = 2;
 
             hr = skininfo->lpVtbl->SetBoneInfluence(skininfo, 1, num_influences, vertices, weights);