[Mesa-dev] [PATCH] nir: remove dead glsl variables before lowering io.

[Dave Airlie]

From: Dave Airlie <airlied at redhat.com>

For cull distance GLSL will let unsized unused arrays get
into the backend, we should nuke those straight away, to
save caring about them later.

This fixes:
arb_separate_shader_objects/linker/large-number-of-unused-varyings
as a side effect (even without culling changes).

Signed-off-by: Dave Airlie <airlied at redhat.com>

Signed-off-by: Dave Airlie <airlied at redhat.com>
---
 src/mesa/drivers/dri/i965/brw_nir.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/mesa/drivers/dri/i965/brw_nir.c b/src/mesa/drivers/dri/i965/brw_nir.c
index 9afd036..6ceac7e 100644
--- a/src/mesa/drivers/dri/i965/brw_nir.c
+++ b/src/mesa/drivers/dri/i965/brw_nir.c
@@ -560,6 +560,8 @@ brw_create_nir(struct brw_context *brw,
    /* First, lower the GLSL IR or Mesa IR to NIR */
    if (shader_prog) {
       nir = glsl_to_nir(shader_prog, stage, options);
+      nir_remove_dead_variables(nir, nir_var_shader_in);
+      nir_remove_dead_variables(nir, nir_var_shader_out);
       OPT_V(nir_lower_io_to_temporaries,
             nir_shader_get_entrypoint(nir),
             true, false);
-- 
2.5.5