aco: Skip TCS s_barrier when VS outputs are not stored in the LDS.

When VS outputs are known to be never stored in LDS, there is no
reason for HS waves to wait for all LS waves to complete. So, the
s_barrier between the LS and HS can be safely skipped.

Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Rhys Perry <pendingchaos02@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7727>

diff --git a/src/amd/compiler/aco_instruction_selection.cpp b/src/amd/compiler/aco_instruction_selection.cpp
index 2bf1c1d..9b73626 100644 (file)
--- a/src/amd/compiler/aco_instruction_selection.cpp
+++ b/src/amd/compiler/aco_instruction_selection.cpp
@@ -11793,7 +11793,11 @@ void select_program(Program *program,
       if (i) {
          Builder bld(ctx.program, ctx.block);
 
-         if (!ngg_gs)
+         /* Skip s_barrier from TCS when VS outputs are not stored in the LDS. */
+         bool tcs_skip_barrier = ctx.stage == vertex_tess_control_hs &&
+                                 ctx.tcs_temp_only_inputs == nir->info.inputs_read;
+
+         if (!ngg_gs && !tcs_skip_barrier)
             create_workgroup_barrier(bld);
 
          if (ctx.stage == vertex_geometry_gs || ctx.stage == tess_eval_geometry_gs) {