diff --git a/src/gallium/drivers/llvmpipe/lp_rast.h b/src/gallium/drivers/llvmpipe/lp_rast.h
index 41a7f5ebbf3..492e4b06ada 100644
--- a/src/gallium/drivers/llvmpipe/lp_rast.h
+++ b/src/gallium/drivers/llvmpipe/lp_rast.h
@@ -61,11 +61,15 @@ struct lp_rast_shader_inputs {
     */
    const struct lp_rast_state *state;
 
-   /* Attribute interpolation:  FIXME: reduce memory waste!
+   /* Attribute interpolation:
+    *
+    * First coefficient is position.
+    *
+    * FIXME: reduce memory waste!
     */
-   float a0[PIPE_MAX_ATTRIBS][4];
-   float dadx[PIPE_MAX_ATTRIBS][4];
-   float dady[PIPE_MAX_ATTRIBS][4];
+   float a0[1 + PIPE_MAX_SHADER_INPUTS][4];
+   float dadx[1 + PIPE_MAX_SHADER_INPUTS][4];
+   float dady[1 + PIPE_MAX_SHADER_INPUTS][4];
 };