source/blender/draw/engines/overlay/shaders/overlay_edit_mesh_vert_no_geom.glsl

@@ -176,10 +176,10 @@ void main()
   /* Enlarge edge for flag display. */
   half_size += (geometry_out.finalColorOuter.a > 0.0) ? max(sizeEdge, 1.0) : 0.0;
 
-#ifdef USE_SMOOTH_WIRE
+  if (do_smooth_wire) {
     /* Add 1 px for AA */
     half_size += 0.5;
-#endif
+  }
 
   vec3 edge_ofs = vec3(half_size * sizeViewportInv, 0.0);