glsl: use bitfield_insert instead of and + shift + or for packing

It is fairly tricky to detect the proper conditions for using bitfield
insert, but easy to just use it up front. This removes a lot of
instructions on nvc0 when invoking the packing builtins.

Signed-off-by: Ilia Mirkin <[email protected]>
Reviewed-by: Matt Turner <[email protected]>

1 files changed, 3 insertions, 0 deletions

diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
index 695644117ac..7a8c4e1b8fa 100644
--- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
+++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
@@ -6019,6 +6019,9 @@ st_link_shader(struct gl_context *ctx, struct gl_shader_program *prog)
                                LOWER_PACK_HALF_2x16 |
                                LOWER_UNPACK_HALF_2x16;
 
+         if (ctx->Extensions.ARB_gpu_shader5)
+            lower_inst |= LOWER_PACK_USE_BFI;
+
          lower_packing_builtins(ir, lower_inst);
       }