radeonsi: add draw_vbo check for a NULL pixel shader

Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>

src/gallium/drivers/radeonsi/si_state.c

@@ -698,6 +698,7 @@ static void *si_create_rs_state(struct pipe_context *ctx,
 	rs->clamp_fragment_color = state->clamp_fragment_color;
 	rs->flatshade = state->flatshade;
 	rs->sprite_coord_enable = state->sprite_coord_enable;
+	rs->rasterizer_discard = state->rasterizer_discard;
 	rs->pa_sc_line_stipple = state->line_stipple_enable ?
 				S_028A0C_LINE_PATTERN(state->line_stipple_pattern) |
 				S_028A0C_REPEAT_COUNT(state->line_stipple_factor) : 0;

src/gallium/drivers/radeonsi/si_state.h

@@ -61,6 +61,7 @@ struct si_state_rasterizer {
 	bool			poly_smooth;
 	bool			uses_poly_offset;
 	bool			clamp_fragment_color;
+	bool			rasterizer_discard;
 };
 
 struct si_dsa_stencil_ref_part {

src/gallium/drivers/radeonsi/si_state_draw.c

@@ -728,6 +728,7 @@ static void si_get_draw_start_count(struct si_context *sctx,
 void si_draw_vbo(struct pipe_context *ctx, const struct pipe_draw_info *info)
 {
 	struct si_context *sctx = (struct si_context *)ctx;
+	struct si_state_rasterizer *rs = sctx->queued.named.rasterizer;
 	struct pipe_index_buffer ib = {};
 	unsigned mask;
 
@@ -735,7 +736,11 @@ void si_draw_vbo(struct pipe_context *ctx, const struct pipe_draw_info *info)
 	    (info->indexed || !info->count_from_stream_output))
 		return;
 
-	if (!sctx->ps_shader.cso || !sctx->vs_shader.cso) {
+	if (!sctx->vs_shader.cso) {
+		assert(0);
+		return;
+	}
+	if (!sctx->ps_shader.cso && (!rs || !rs->rasterizer_discard)) {
 		assert(0);
 		return;
 	}