radeonsi: add dummy implementation of si_nir_scan_tess_ctrl()

Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>

src/gallium/drivers/radeonsi/si_shader.h

@@ -652,6 +652,9 @@ const char *si_get_shader_name(const struct si_shader *shader, unsigned processo
 /* si_shader_nir.c */
 void si_nir_scan_shader(const struct nir_shader *nir,
 			struct tgsi_shader_info *info);
+void si_nir_scan_tess_ctrl(const struct nir_shader *nir,
+			   const struct tgsi_shader_info *info,
+			   struct tgsi_tessctrl_info *out);
 void si_lower_nir(struct si_shader_selector *sel);
 
 /* Inline helpers. */

src/gallium/drivers/radeonsi/si_shader_nir.c

@@ -130,6 +130,25 @@ static void scan_instruction(struct tgsi_shader_info *info,
 	}
 }
 
+void si_nir_scan_tess_ctrl(const struct nir_shader *nir,
+			   const struct tgsi_shader_info *info,
+			   struct tgsi_tessctrl_info *out)
+{
+	memset(out, 0, sizeof(*out));
+
+	if (nir->info.stage != MESA_SHADER_TESS_CTRL)
+		return;
+
+	/* Initial value = true. Here the pass will accumulate results from
+	 * multiple segments surrounded by barriers. If tess factors aren't
+	 * written at all, it's a shader bug and we don't care if this will be
+	 * true.
+	 */
+	out->tessfactors_are_def_in_all_invocs = true;
+
+	/* TODO: Implement scanning of tess factors, see tgsi backend. */
+}
+
 void si_nir_scan_shader(const struct nir_shader *nir,
 			struct tgsi_shader_info *info)
 {

src/gallium/drivers/radeonsi/si_state_shaders.c

@@ -2005,6 +2005,7 @@ static void *si_create_shader_selector(struct pipe_context *ctx,
 		sel->nir = state->ir.nir;
 
 		si_nir_scan_shader(sel->nir, &sel->info);
+		si_nir_scan_tess_ctrl(sel->nir, &sel->info, &sel->tcs_info);
 
 		si_lower_nir(sel);
 	}