| /* |
| * Copyright © 2018 Red Hat |
| * Copyright © 2019 Valve Corporation |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a |
| * copy of this software and associated documentation files (the "Software"), |
| * to deal in the Software without restriction, including without limitation |
| * the rights to use, copy, modify, merge, publish, distribute, sublicense, |
| * and/or sell copies of the Software, and to permit persons to whom the |
| * Software is furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice (including the next |
| * paragraph) shall be included in all copies or substantial portions of the |
| * Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
| * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
| * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS |
| * IN THE SOFTWARE. |
| * |
| * Authors: |
| * Rob Clark (robdclark@gmail.com> |
| * Daniel Schürmann (daniel.schuermann@campus.tu-berlin.de) |
| * Rhys Perry (pendingchaos02@gmail.com) |
| * |
| */ |
| |
| #include "nir.h" |
| |
| |
| /* |
| * A simple pass that moves some instructions into the least common |
| * anscestor of consuming instructions. |
| */ |
| |
| bool |
| nir_can_move_instr(nir_instr *instr, nir_move_options options) |
| { |
| switch (instr->type) { |
| case nir_instr_type_load_const: |
| case nir_instr_type_ssa_undef: { |
| return options & nir_move_const_undef; |
| } |
| case nir_instr_type_alu: { |
| if (nir_op_is_vec(nir_instr_as_alu(instr)->op) || |
| nir_instr_as_alu(instr)->op == nir_op_b2i32) |
| return options & nir_move_copies; |
| if (nir_alu_instr_is_comparison(nir_instr_as_alu(instr))) |
| return options & nir_move_comparisons; |
| return false; |
| } |
| case nir_instr_type_intrinsic: { |
| nir_intrinsic_instr *intrin = nir_instr_as_intrinsic(instr); |
| switch (intrin->intrinsic) { |
| case nir_intrinsic_load_ubo: |
| return options & nir_move_load_ubo; |
| case nir_intrinsic_load_input: |
| case nir_intrinsic_load_interpolated_input: |
| case nir_intrinsic_load_per_vertex_input: |
| return options & nir_move_load_input; |
| default: |
| return false; |
| } |
| } |
| default: |
| return false; |
| } |
| } |
| |
| static nir_loop * |
| get_innermost_loop(nir_cf_node *node) |
| { |
| for (; node != NULL; node = node->parent) { |
| if (node->type == nir_cf_node_loop) |
| return (nir_loop*)node; |
| } |
| return NULL; |
| } |
| |
| static bool |
| loop_contains_block(nir_loop *loop, nir_block *block) |
| { |
| nir_block *before = nir_cf_node_as_block(nir_cf_node_prev(&loop->cf_node)); |
| nir_block *after = nir_cf_node_as_block(nir_cf_node_next(&loop->cf_node)); |
| |
| return block->index > before->index && block->index < after->index; |
| } |
| |
| /* Given the LCA of all uses and the definition, find a block on the path |
| * between them in the dominance tree that is outside of as many loops as |
| * possible. If "sink_out_of_loops" is false, then we disallow sinking the |
| * definition outside of the loop it's defined in (if any). |
| */ |
| |
| static nir_block * |
| adjust_block_for_loops(nir_block *use_block, nir_block *def_block, |
| bool sink_out_of_loops) |
| { |
| nir_loop *def_loop = NULL; |
| if (!sink_out_of_loops) |
| def_loop = get_innermost_loop(&def_block->cf_node); |
| |
| for (nir_block *cur_block = use_block; cur_block != def_block->imm_dom; |
| cur_block = cur_block->imm_dom) { |
| if (!sink_out_of_loops && def_loop && |
| !loop_contains_block(def_loop, use_block)) { |
| use_block = cur_block; |
| continue; |
| } |
| |
| nir_cf_node *next = nir_cf_node_next(&cur_block->cf_node); |
| if (next && next->type == nir_cf_node_loop) { |
| nir_loop *following_loop = nir_cf_node_as_loop(next); |
| if (loop_contains_block(following_loop, use_block)) { |
| use_block = cur_block; |
| continue; |
| } |
| } |
| } |
| |
| return use_block; |
| } |
| |
| /* iterate a ssa def's use's and try to find a more optimal block to |
| * move it to, using the dominance tree. In short, if all of the uses |
| * are contained in a single block, the load will be moved there, |
| * otherwise it will be move to the least common ancestor block of all |
| * the uses |
| */ |
| static nir_block * |
| get_preferred_block(nir_ssa_def *def, bool sink_into_loops, bool sink_out_of_loops) |
| { |
| nir_block *lca = NULL; |
| |
| nir_foreach_use(use, def) { |
| nir_instr *instr = use->parent_instr; |
| nir_block *use_block = instr->block; |
| |
| /* |
| * Kind of an ugly special-case, but phi instructions |
| * need to appear first in the block, so by definition |
| * we can't move an instruction into a block where it is |
| * consumed by a phi instruction. We could conceivably |
| * move it into a dominator block. |
| */ |
| if (instr->type == nir_instr_type_phi) { |
| nir_phi_instr *phi = nir_instr_as_phi(instr); |
| nir_block *phi_lca = NULL; |
| nir_foreach_phi_src(src, phi) { |
| if (&src->src == use) |
| phi_lca = nir_dominance_lca(phi_lca, src->pred); |
| } |
| use_block = phi_lca; |
| } |
| |
| lca = nir_dominance_lca(lca, use_block); |
| } |
| |
| nir_foreach_if_use(use, def) { |
| nir_block *use_block = |
| nir_cf_node_as_block(nir_cf_node_prev(&use->parent_if->cf_node)); |
| |
| lca = nir_dominance_lca(lca, use_block); |
| } |
| |
| /* If we're moving a load_ubo or load_interpolated_input, we don't want to |
| * sink it down into loops, which may result in accessing memory or shared |
| * functions multiple times. Sink it just above the start of the loop |
| * where it's used. For load_consts, undefs, and comparisons, we expect |
| * the driver to be able to emit them as simple ALU ops, so sinking as far |
| * in as we can go is probably worth it for register pressure. |
| */ |
| if (!sink_into_loops) { |
| lca = adjust_block_for_loops(lca, def->parent_instr->block, |
| sink_out_of_loops); |
| assert(nir_block_dominates(def->parent_instr->block, lca)); |
| } else { |
| /* sink_into_loops = true and sink_out_of_loops = false isn't |
| * implemented yet because it's not used. |
| */ |
| assert(sink_out_of_loops); |
| } |
| |
| |
| return lca; |
| } |
| |
| /* insert before first non-phi instruction: */ |
| static void |
| insert_after_phi(nir_instr *instr, nir_block *block) |
| { |
| nir_foreach_instr(instr2, block) { |
| if (instr2->type == nir_instr_type_phi) |
| continue; |
| |
| exec_node_insert_node_before(&instr2->node, |
| &instr->node); |
| |
| return; |
| } |
| |
| /* if haven't inserted it, push to tail (ie. empty block or possibly |
| * a block only containing phi's?) |
| */ |
| exec_list_push_tail(&block->instr_list, &instr->node); |
| } |
| |
| bool |
| nir_opt_sink(nir_shader *shader, nir_move_options options) |
| { |
| bool progress = false; |
| |
| nir_foreach_function(function, shader) { |
| if (!function->impl) |
| continue; |
| |
| nir_metadata_require(function->impl, |
| nir_metadata_block_index | nir_metadata_dominance); |
| |
| nir_foreach_block_reverse(block, function->impl) { |
| nir_foreach_instr_reverse_safe(instr, block) { |
| if (!nir_can_move_instr(instr, options)) |
| continue; |
| |
| nir_ssa_def *def = nir_instr_ssa_def(instr); |
| |
| bool sink_into_loops = instr->type != nir_instr_type_intrinsic; |
| /* Don't sink load_ubo out of loops because that can make its |
| * resource divergent and break code like that which is generated |
| * by nir_lower_non_uniform_access. |
| */ |
| bool sink_out_of_loops = |
| instr->type != nir_instr_type_intrinsic || |
| nir_instr_as_intrinsic(instr)->intrinsic != nir_intrinsic_load_ubo; |
| nir_block *use_block = |
| get_preferred_block(def, sink_into_loops, sink_out_of_loops); |
| |
| if (!use_block || use_block == instr->block) |
| continue; |
| |
| exec_node_remove(&instr->node); |
| |
| insert_after_phi(instr, use_block); |
| |
| instr->block = use_block; |
| |
| progress = true; |
| } |
| } |
| |
| nir_metadata_preserve(function->impl, |
| nir_metadata_block_index | nir_metadata_dominance); |
| } |
| |
| return progress; |
| } |
