i965: Fix register allocation of GLSL fp inputs.

Before, if the VP output something that is in the attributes coming into
the WM but which isn't used by the WM, then WM would end up reading subsequent
varyings from the wrong places.  This was visible with a GLSL demo
using gl_PointSize in the VS and a varying in the WM, as point size is in
the VUE but not used by the WM.  There is now a regression test in piglit,
glsl-unused-varying.

(cherry picked from commit 0f5113deed91611ecdda6596542530b1849bb161)

1 files changed, 1 insertions, 0 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_wm.h b/src/mesa/drivers/dri/i965/brw_wm.h
index 0408034c38..295fed851b 100644
--- a/src/mesa/drivers/dri/i965/brw_wm.h
+++ b/src/mesa/drivers/dri/i965/brw_wm.h
@@ -75,6 +75,7 @@ struct brw_wm_prog_key {
    GLuint program_string_id:32;
    GLuint origin_x, origin_y;
    GLuint drawable_height;
+   GLuint vp_outputs_written;
 };