anv: Use nir_lower_multiview pass
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6514>
diff --git a/src/intel/vulkan/anv_nir_lower_multiview.c b/src/intel/vulkan/anv_nir_lower_multiview.c
index 75bc018..0502b1e 100644
--- a/src/intel/vulkan/anv_nir_lower_multiview.c
+++ b/src/intel/vulkan/anv_nir_lower_multiview.c
@@ -150,166 +150,6 @@
return state->view_index;
}
-/* Primitive Replication allows a shader to write different positions for each
- * view in the same execution. If only the position depends on the view, then
- * it is possible to use the feature instead of instancing to implement
- * multiview.
- */
-static bool
-lower_multiview_with_primitive_replication(nir_shader *shader,
- struct anv_graphics_pipeline *pipeline)
-{
- if (shader->info.stage == MESA_SHADER_FRAGMENT)
- return false;
-
- assert(shader->info.stage == MESA_SHADER_VERTEX);
-
- uint32_t view_mask = pipeline->subpass->view_mask;
- int view_count = util_bitcount(view_mask);
- assert(view_count > 1 && view_count <= MAX_VIEWS_FOR_PRIMITIVE_REPLICATION);
-
- nir_function_impl *entrypoint = nir_shader_get_entrypoint(shader);
-
- /* Update position to refer to an array. */
- nir_variable *pos_var = NULL;
- nir_foreach_shader_out_variable(var, shader) {
- if (var->data.location == VARYING_SLOT_POS) {
- assert(var->type == glsl_vec4_type());
- var->type = glsl_array_type(glsl_vec4_type(), view_count, 0);
- var->data.per_view = true;
- pos_var = var;
- break;
- }
- }
-
- assert(pos_var);
-
- nir_cf_list body;
- nir_cf_list_extract(&body, &entrypoint->body);
-
- nir_builder b;
- nir_builder_init(&b, entrypoint);
- b.cursor = nir_after_cf_list(&entrypoint->body);
-
- /* Fill Layer ID with zero. Replication will use that as base to apply the
- * RTAI offsets.
- */
- nir_variable *layer_id_out =
- nir_variable_create(shader, nir_var_shader_out,
- glsl_int_type(), "layer ID");
- layer_id_out->data.location = VARYING_SLOT_LAYER;
- nir_store_var(&b, layer_id_out, nir_imm_zero(&b, 1, 32), 0x1);
-
- /* Loop Index will go from 0 to view_count. */
- nir_variable *loop_index_var =
- nir_local_variable_create(entrypoint, glsl_uint_type(), "loop_index");
- nir_deref_instr *loop_index_deref = nir_build_deref_var(&b, loop_index_var);
- nir_store_deref(&b, loop_index_deref, nir_imm_int(&b, 0), 1);
-
- /* Array of view index values that are active in the loop. Note that the
- * loop index only matches the view index if there are no gaps in the
- * view_mask.
- */
- nir_variable *view_index_var = nir_local_variable_create(
- entrypoint, glsl_array_type(glsl_uint_type(), view_count, 0), "view_index");
- nir_deref_instr *view_index_deref = nir_build_deref_var(&b, view_index_var);
- {
- int array_position = 0;
- uint32_t view_index;
- for_each_bit(view_index, view_mask) {
- nir_store_deref(&b, nir_build_deref_array_imm(&b, view_index_deref, array_position),
- nir_imm_int(&b, view_index), 1);
- array_position++;
- }
- }
-
- /* Create the equivalent of
- *
- * while (true):
- * if (loop_index >= view_count):
- * break
- *
- * view_index = active_indices[loop_index]
- * pos_deref = &pos[loop_index]
- *
- * # Placeholder for the body to be reinserted.
- *
- * loop_index += 1
- *
- * Later both `view_index` and `pos_deref` will be used to rewrite the
- * original shader body.
- */
-
- nir_loop* loop = nir_push_loop(&b);
-
- nir_ssa_def *loop_index = nir_load_deref(&b, loop_index_deref);
- nir_ssa_def *cmp = nir_ige(&b, loop_index, nir_imm_int(&b, view_count));
- nir_if *loop_check = nir_push_if(&b, cmp);
- nir_jump(&b, nir_jump_break);
- nir_pop_if(&b, loop_check);
-
- nir_ssa_def *view_index =
- nir_load_deref(&b, nir_build_deref_array(&b, view_index_deref, loop_index));
- nir_deref_instr *pos_deref =
- nir_build_deref_array(&b, nir_build_deref_var(&b, pos_var), loop_index);
-
- nir_store_deref(&b, loop_index_deref, nir_iadd_imm(&b, loop_index, 1), 1);
- nir_pop_loop(&b, loop);
-
- /* Reinsert the body. */
- b.cursor = nir_after_instr(&pos_deref->instr);
- nir_cf_reinsert(&body, b.cursor);
-
- nir_foreach_block(block, entrypoint) {
- nir_foreach_instr_safe(instr, block) {
- if (instr->type != nir_instr_type_intrinsic)
- continue;
-
- nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
-
- switch (intrin->intrinsic) {
- case nir_intrinsic_load_view_index: {
- assert(intrin->dest.is_ssa);
- nir_ssa_def_rewrite_uses(&intrin->dest.ssa, nir_src_for_ssa(view_index));
- break;
- }
-
- case nir_intrinsic_store_deref: {
- nir_variable *var = nir_intrinsic_get_var(intrin, 0);
- if (var == pos_var) {
- nir_deref_instr *old_deref = nir_src_as_deref(intrin->src[0]);
-
- nir_instr_rewrite_src(instr, &intrin->src[0],
- nir_src_for_ssa(&pos_deref->dest.ssa));
-
- /* Remove old deref since it has the wrong type. */
- nir_deref_instr_remove_if_unused(old_deref);
- }
- break;
- }
-
- case nir_intrinsic_load_deref:
- if (nir_intrinsic_get_var(intrin, 0) == pos_var) {
- unreachable("Should have lowered I/O to temporaries "
- "so no load_deref on position output is expected.");
- }
- break;
-
- case nir_intrinsic_copy_deref:
- unreachable("Should have lowered copy_derefs at this point");
- break;
-
- default:
- /* Do nothing. */
- break;
- }
- }
- }
-
- nir_metadata_preserve(entrypoint, nir_metadata_none);
- return true;
-}
-
bool
anv_nir_lower_multiview(nir_shader *shader,
struct anv_graphics_pipeline *pipeline)
@@ -321,16 +161,42 @@
if (view_mask == 0)
return false;
- if (pipeline->use_primitive_replication)
- return lower_multiview_with_primitive_replication(shader, pipeline);
+ /* This pass assumes a single entrypoint */
+ nir_function_impl *entrypoint = nir_shader_get_entrypoint(shader);
+
+ /* Primitive Replication allows a shader to write different positions for
+ * each view in the same execution. If only the position depends on the
+ * view, then it is possible to use the feature instead of instancing to
+ * implement multiview.
+ */
+ if (pipeline->use_primitive_replication) {
+ if (shader->info.stage == MESA_SHADER_FRAGMENT)
+ return false;
+
+ bool progress = nir_lower_multiview(shader, pipeline->subpass->view_mask);
+
+ if (progress) {
+ nir_builder b;
+ nir_builder_init(&b, entrypoint);
+ b.cursor = nir_before_cf_list(&entrypoint->body);
+
+ /* Fill Layer ID with zero. Replication will use that as base to
+ * apply the RTAI offsets.
+ */
+ nir_variable *layer_id_out =
+ nir_variable_create(shader, nir_var_shader_out,
+ glsl_int_type(), "layer ID");
+ layer_id_out->data.location = VARYING_SLOT_LAYER;
+ nir_store_var(&b, layer_id_out, nir_imm_zero(&b, 1, 32), 0x1);
+ }
+
+ return progress;
+ }
struct lower_multiview_state state = {
.view_mask = view_mask,
};
- /* This pass assumes a single entrypoint */
- nir_function_impl *entrypoint = nir_shader_get_entrypoint(shader);
-
nir_builder_init(&state.builder, entrypoint);
bool progress = false;
@@ -401,141 +267,6 @@
return progress;
}
-static bool
-shader_writes_to_memory(nir_shader *shader)
-{
- /* With multiview, we would need to ensure that memory writes happen either
- * once or once per view. Since combination of multiview and memory writes
- * is not expected, we'll just skip this optimization in this case.
- */
-
- nir_function_impl *entrypoint = nir_shader_get_entrypoint(shader);
-
- nir_foreach_block(block, entrypoint) {
- nir_foreach_instr(instr, block) {
- if (instr->type != nir_instr_type_intrinsic)
- continue;
- nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
-
- switch (intrin->intrinsic) {
- case nir_intrinsic_deref_atomic_add:
- case nir_intrinsic_deref_atomic_imin:
- case nir_intrinsic_deref_atomic_umin:
- case nir_intrinsic_deref_atomic_imax:
- case nir_intrinsic_deref_atomic_umax:
- case nir_intrinsic_deref_atomic_and:
- case nir_intrinsic_deref_atomic_or:
- case nir_intrinsic_deref_atomic_xor:
- case nir_intrinsic_deref_atomic_exchange:
- case nir_intrinsic_deref_atomic_comp_swap:
- case nir_intrinsic_store_ssbo:
- case nir_intrinsic_ssbo_atomic_add:
- case nir_intrinsic_ssbo_atomic_imin:
- case nir_intrinsic_ssbo_atomic_umin:
- case nir_intrinsic_ssbo_atomic_imax:
- case nir_intrinsic_ssbo_atomic_umax:
- case nir_intrinsic_ssbo_atomic_and:
- case nir_intrinsic_ssbo_atomic_or:
- case nir_intrinsic_ssbo_atomic_xor:
- case nir_intrinsic_ssbo_atomic_exchange:
- case nir_intrinsic_ssbo_atomic_comp_swap:
- case nir_intrinsic_store_shared:
- case nir_intrinsic_shared_atomic_add:
- case nir_intrinsic_shared_atomic_imin:
- case nir_intrinsic_shared_atomic_umin:
- case nir_intrinsic_shared_atomic_imax:
- case nir_intrinsic_shared_atomic_umax:
- case nir_intrinsic_shared_atomic_and:
- case nir_intrinsic_shared_atomic_or:
- case nir_intrinsic_shared_atomic_xor:
- case nir_intrinsic_shared_atomic_exchange:
- case nir_intrinsic_shared_atomic_comp_swap:
- case nir_intrinsic_image_deref_store:
- case nir_intrinsic_image_deref_atomic_add:
- case nir_intrinsic_image_deref_atomic_umin:
- case nir_intrinsic_image_deref_atomic_umax:
- case nir_intrinsic_image_deref_atomic_imin:
- case nir_intrinsic_image_deref_atomic_imax:
- case nir_intrinsic_image_deref_atomic_and:
- case nir_intrinsic_image_deref_atomic_or:
- case nir_intrinsic_image_deref_atomic_xor:
- case nir_intrinsic_image_deref_atomic_exchange:
- case nir_intrinsic_image_deref_atomic_comp_swap:
- return true;
-
- default:
- /* Keep walking. */
- break;
- }
- }
- }
-
- return false;
-}
-
-static bool
-shader_uses_view_index(nir_shader *shader)
-{
- nir_function_impl *entrypoint = nir_shader_get_entrypoint(shader);
-
- nir_foreach_block(block, entrypoint) {
- nir_foreach_instr(instr, block) {
- if (instr->type != nir_instr_type_intrinsic)
- continue;
-
- nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr);
- if (intrin->intrinsic == nir_intrinsic_load_view_index)
- return true;
- }
- }
-
- return false;
-}
-
-static bool
-shader_only_position_uses_view_index(nir_shader *shader)
-{
- nir_shader *shader_no_position = nir_shader_clone(NULL, shader);
- nir_function_impl *entrypoint = nir_shader_get_entrypoint(shader_no_position);
-
- /* Remove the store position from a cloned shader. */
- nir_foreach_block(block, entrypoint) {
- nir_foreach_instr_safe(instr, block) {
- if (instr->type != nir_instr_type_intrinsic)
- continue;
-
- nir_intrinsic_instr *store = nir_instr_as_intrinsic(instr);
- if (store->intrinsic != nir_intrinsic_store_deref)
- continue;
-
- nir_variable *var = nir_intrinsic_get_var(store, 0);
- if (var->data.location != VARYING_SLOT_POS)
- continue;
-
- nir_instr_remove(&store->instr);
- }
- }
-
- /* Clean up shader so unused load_view_index intrinsics are removed. */
- bool progress;
- do {
- progress = false;
- progress |= nir_opt_dead_cf(shader_no_position);
-
- /* Peephole select will drop if-blocks that have then and else empty,
- * which will remove the usage of an SSA in the condition.
- */
- progress |= nir_opt_peephole_select(shader_no_position, 0, false, false);
-
- progress |= nir_opt_dce(shader_no_position);
- } while (progress);
-
- bool uses_view_index = shader_uses_view_index(shader_no_position);
-
- ralloc_free(shader_no_position);
- return !uses_view_index;
-}
-
bool
anv_check_for_primitive_replication(nir_shader **shaders,
struct anv_graphics_pipeline *pipeline)
@@ -570,19 +301,9 @@
if (view_count == 1 || view_count > primitive_replication_max_views)
return false;
- bool vs_writes_position = false;
- nir_foreach_shader_out_variable(var, shaders[MESA_SHADER_VERTEX]) {
- if (var->data.location == VARYING_SLOT_POS) {
- vs_writes_position = true;
- break;
- }
- }
-
- /* Don't bother handling this edge case with Primitive Replication. */
- if (!vs_writes_position)
+ /* We can't access the view index in the fragment shader. */
+ if (nir_shader_uses_view_index(shaders[MESA_SHADER_FRAGMENT]))
return false;
- return !shader_uses_view_index(shaders[MESA_SHADER_FRAGMENT]) &&
- !shader_writes_to_memory(shaders[MESA_SHADER_VERTEX]) &&
- shader_only_position_uses_view_index(shaders[MESA_SHADER_VERTEX]);
+ return nir_can_lower_multiview(shaders[MESA_SHADER_VERTEX]);
}
