radeonsi/nir: enable nir_opt_move_discards_to_top pass

Since it affects discards and demotes, this commit also moves the
usage of nir_lower_discard_or_demote ealier.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10522>

diff --git a/src/gallium/drivers/radeonsi/si_shader_nir.c b/src/gallium/drivers/radeonsi/si_shader_nir.c
index 8296c15..6f97254 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_shader_nir.c
+++ b/src/gallium/drivers/radeonsi/si_shader_nir.c
@@ -595,6 +595,9 @@ void si_nir_opts(struct si_screen *sscreen, struct nir_shader *nir, bool first)
          NIR_PASS(progress, nir, nir_opt_loop_unroll, 0);
       }
 
+      if (nir->info.stage == MESA_SHADER_FRAGMENT)
+         NIR_PASS_V(nir, nir_opt_move_discards_to_top);
+
       if (sscreen->options.fp16)
          NIR_PASS(progress, nir, nir_opt_vectorize, NULL, NULL);
    } while (progress);
@@ -822,6 +825,9 @@ static void si_lower_nir(struct si_screen *sscreen, struct nir_shader *nir)
    };
    NIR_PASS_V(nir, nir_lower_subgroups, &subgroups_options);
 
+   NIR_PASS_V(nir, nir_lower_discard_or_demote,
+              sscreen->debug_flags & DBG(FS_CORRECT_DERIVS_AFTER_KILL));
+
    /* Lower load constants to scalar and then clean up the mess */
    NIR_PASS_V(nir, nir_lower_load_const_to_scalar);
    NIR_PASS_V(nir, nir_lower_var_copies);
@@ -883,9 +889,6 @@ static void si_lower_nir(struct si_screen *sscreen, struct nir_shader *nir)
       si_late_optimize_16bit_samplers(sscreen, nir);
 
    NIR_PASS_V(nir, nir_remove_dead_variables, nir_var_function_temp, NULL);
-
-   NIR_PASS_V(nir, nir_lower_discard_or_demote,
-              sscreen->debug_flags & DBG(FS_CORRECT_DERIVS_AFTER_KILL));
 }
 
 void si_finalize_nir(struct pipe_screen *screen, void *nirptr, bool optimize)