| /* |
| * Copyright © 2014 Intel 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: |
| * Connor Abbott (cwabbott0@gmail.com) |
| * |
| */ |
| |
| #include "nir.h" |
| #include "nir_worklist.h" |
| |
| /* SSA-based mark-and-sweep dead code elimination */ |
| |
| static void |
| mark_and_push(nir_instr_worklist *wl, nir_instr *instr) |
| { |
| nir_instr_worklist_push_tail(wl, instr); |
| instr->pass_flags = 1; |
| } |
| |
| static bool |
| mark_live_cb(nir_src *src, void *_state) |
| { |
| nir_instr_worklist *worklist = (nir_instr_worklist *) _state; |
| |
| if (src->is_ssa && !src->ssa->parent_instr->pass_flags) |
| mark_and_push(worklist, src->ssa->parent_instr); |
| |
| return true; |
| } |
| |
| static void |
| init_instr(nir_instr *instr, nir_instr_worklist *worklist) |
| { |
| nir_alu_instr *alu_instr; |
| nir_deref_instr *deref_instr; |
| nir_intrinsic_instr *intrin_instr; |
| nir_tex_instr *tex_instr; |
| |
| /* We use the pass_flags to store the live/dead information. In DCE, we |
| * just treat it as a zero/non-zero boolean for whether or not the |
| * instruction is live. |
| */ |
| instr->pass_flags = 0; |
| |
| switch (instr->type) { |
| case nir_instr_type_call: |
| case nir_instr_type_jump: |
| mark_and_push(worklist, instr); |
| break; |
| |
| case nir_instr_type_alu: |
| alu_instr = nir_instr_as_alu(instr); |
| if (!alu_instr->dest.dest.is_ssa) |
| mark_and_push(worklist, instr); |
| break; |
| |
| case nir_instr_type_deref: |
| deref_instr = nir_instr_as_deref(instr); |
| if (!deref_instr->dest.is_ssa) |
| mark_and_push(worklist, instr); |
| break; |
| |
| case nir_instr_type_intrinsic: |
| intrin_instr = nir_instr_as_intrinsic(instr); |
| if (nir_intrinsic_infos[intrin_instr->intrinsic].flags & |
| NIR_INTRINSIC_CAN_ELIMINATE) { |
| if (nir_intrinsic_infos[intrin_instr->intrinsic].has_dest && |
| !intrin_instr->dest.is_ssa) { |
| mark_and_push(worklist, instr); |
| } |
| } else { |
| mark_and_push(worklist, instr); |
| } |
| break; |
| |
| case nir_instr_type_tex: |
| tex_instr = nir_instr_as_tex(instr); |
| if (!tex_instr->dest.is_ssa) |
| mark_and_push(worklist, instr); |
| break; |
| |
| default: |
| break; |
| } |
| } |
| |
| static bool |
| init_block(nir_block *block, nir_instr_worklist *worklist) |
| { |
| nir_foreach_instr(instr, block) |
| init_instr(instr, worklist); |
| |
| nir_if *following_if = nir_block_get_following_if(block); |
| if (following_if) { |
| if (following_if->condition.is_ssa && |
| !following_if->condition.ssa->parent_instr->pass_flags) |
| mark_and_push(worklist, following_if->condition.ssa->parent_instr); |
| } |
| |
| return true; |
| } |
| |
| static bool |
| nir_opt_dce_impl(nir_function_impl *impl) |
| { |
| nir_instr_worklist *worklist = nir_instr_worklist_create(); |
| |
| nir_foreach_block(block, impl) { |
| init_block(block, worklist); |
| } |
| |
| nir_foreach_instr_in_worklist(instr, worklist) |
| nir_foreach_src(instr, mark_live_cb, worklist); |
| |
| nir_instr_worklist_destroy(worklist); |
| |
| bool progress = false; |
| |
| nir_foreach_block(block, impl) { |
| nir_foreach_instr_safe(instr, block) { |
| if (!instr->pass_flags) { |
| nir_instr_remove(instr); |
| progress = true; |
| } |
| } |
| } |
| |
| if (progress) { |
| nir_metadata_preserve(impl, nir_metadata_block_index | |
| nir_metadata_dominance); |
| } else { |
| nir_metadata_preserve(impl, nir_metadata_all); |
| } |
| |
| return progress; |
| } |
| |
| bool |
| nir_opt_dce(nir_shader *shader) |
| { |
| bool progress = false; |
| nir_foreach_function(function, shader) { |
| if (function->impl && nir_opt_dce_impl(function->impl)) |
| progress = true; |
| } |
| |
| return progress; |
| } |