diff --git a/docs/envvars.html b/docs/envvars.html
index e21b7c1aaa0..253aaf26dcd 100644
--- a/docs/envvars.html
+++ b/docs/envvars.html
@@ -164,6 +164,8 @@ See the <a href="xlibdriver.html">Xlib software driver page</a> for details.
    <li>nodualobj - suppress generation of dual-object geometry shader code</li>
    <li>optimizer - dump shader assembly to files at each optimization pass and iteration that make progress</li>
    <li>vec4 - force vec4 mode in vertex shader</li>
+   <li>spill_fs - force spilling of all registers in the scalar backend (useful to debug spilling code)</li>
+   <li>spill_vec4 - force spilling of all registers in the vec4 backend (useful to debug spilling code)</li>
 </ul>
 </ul>