1/* 2 * Copyright (C) 2014 Rob Clark <robclark@freedesktop.org> 3 * 4 * Permission is hereby granted, free of charge, to any person obtaining a 5 * copy of this software and associated documentation files (the "Software"), 6 * to deal in the Software without restriction, including without limitation 7 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 8 * and/or sell copies of the Software, and to permit persons to whom the 9 * Software is furnished to do so, subject to the following conditions: 10 * 11 * The above copyright notice and this permission notice (including the next 12 * paragraph) shall be included in all copies or substantial portions of the 13 * Software. 14 * 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 20 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 21 * SOFTWARE. 22 * 23 * Authors: 24 * Rob Clark <robclark@freedesktop.org> 25 */ 26 27#include "util/u_math.h" 28 29#include "ir3.h" 30#include "ir3_shader.h" 31 32/* 33 * Dead code elimination: 34 */ 35 36static void 37mark_array_use(struct ir3_instruction *instr, struct ir3_register *reg) 38{ 39 if (reg->flags & IR3_REG_ARRAY) { 40 struct ir3_array *arr = 41 ir3_lookup_array(instr->block->shader, reg->array.id); 42 arr->unused = false; 43 } 44} 45 46static void 47instr_dce(struct ir3_instruction *instr, bool falsedep) 48{ 49 /* don't mark falsedep's as used, but otherwise process them normally: */ 50 if (!falsedep) 51 instr->flags &= ~IR3_INSTR_UNUSED; 52 53 if (ir3_instr_check_mark(instr)) 54 return; 55 56 foreach_dst (dst, instr) { 57 if (is_dest_gpr(dst)) 58 mark_array_use(instr, dst); 59 } 60 61 foreach_src (reg, instr) 62 mark_array_use(instr, reg); /* src */ 63 64 foreach_ssa_src_n (src, i, instr) { 65 instr_dce(src, __is_false_dep(instr, i)); 66 } 67} 68 69static bool 70remove_unused_by_block(struct ir3_block *block) 71{ 72 bool progress = false; 73 foreach_instr_safe (instr, &block->instr_list) { 74 if (instr->opc == OPC_END || instr->opc == OPC_CHSH || 75 instr->opc == OPC_CHMASK) 76 continue; 77 if (instr->flags & IR3_INSTR_UNUSED) { 78 if (instr->opc == OPC_META_SPLIT) { 79 struct ir3_instruction *src = ssa(instr->srcs[0]); 80 /* tex (cat5) instructions have a writemask, so we can 81 * mask off unused components. Other instructions do not. 82 */ 83 if (src && is_tex_or_prefetch(src) && (src->dsts[0]->wrmask > 1)) { 84 src->dsts[0]->wrmask &= ~(1 << instr->split.off); 85 } 86 } 87 88 /* prune false-deps, etc: */ 89 foreach_ssa_use (use, instr) 90 foreach_ssa_srcp_n (srcp, n, use) 91 if (*srcp == instr) 92 *srcp = NULL; 93 94 list_delinit(&instr->node); 95 progress = true; 96 } 97 } 98 return progress; 99} 100 101static bool 102find_and_remove_unused(struct ir3 *ir, struct ir3_shader_variant *so) 103{ 104 unsigned i; 105 bool progress = false; 106 107 ir3_clear_mark(ir); 108 109 /* initially mark everything as unused, we'll clear the flag as we 110 * visit the instructions: 111 */ 112 foreach_block (block, &ir->block_list) { 113 foreach_instr (instr, &block->instr_list) { 114 if (instr->opc == OPC_META_INPUT) { 115 /* special case, if pre-fs texture fetch used, we cannot 116 * eliminate the barycentric i/j input 117 */ 118 if (so->num_sampler_prefetch && 119 instr->input.sysval == SYSTEM_VALUE_BARYCENTRIC_PERSP_PIXEL) 120 continue; 121 122 /* Without GS header geometry shader is never invoked. */ 123 if (instr->input.sysval == SYSTEM_VALUE_GS_HEADER_IR3) 124 continue; 125 } 126 127 instr->flags |= IR3_INSTR_UNUSED; 128 } 129 } 130 131 foreach_array (arr, &ir->array_list) 132 arr->unused = true; 133 134 foreach_block (block, &ir->block_list) { 135 for (i = 0; i < block->keeps_count; i++) 136 instr_dce(block->keeps[i], false); 137 138 /* We also need to account for if-condition: */ 139 if (block->condition) 140 instr_dce(block->condition, false); 141 } 142 143 /* remove un-used instructions: */ 144 foreach_block (block, &ir->block_list) { 145 progress |= remove_unused_by_block(block); 146 } 147 148 /* remove un-used arrays: */ 149 foreach_array_safe (arr, &ir->array_list) { 150 if (arr->unused) 151 list_delinit(&arr->node); 152 } 153 154 /* fixup wrmask of split instructions to account for adjusted tex 155 * wrmask's: 156 */ 157 foreach_block (block, &ir->block_list) { 158 foreach_instr (instr, &block->instr_list) { 159 if (instr->opc != OPC_META_SPLIT) 160 continue; 161 162 struct ir3_instruction *src = ssa(instr->srcs[0]); 163 if (!is_tex_or_prefetch(src)) 164 continue; 165 166 instr->srcs[0]->wrmask = src->dsts[0]->wrmask; 167 } 168 } 169 170 for (i = 0; i < ir->a0_users_count; i++) { 171 struct ir3_instruction *instr = ir->a0_users[i]; 172 if (instr && (instr->flags & IR3_INSTR_UNUSED)) 173 ir->a0_users[i] = NULL; 174 } 175 176 for (i = 0; i < ir->a1_users_count; i++) { 177 struct ir3_instruction *instr = ir->a1_users[i]; 178 if (instr && (instr->flags & IR3_INSTR_UNUSED)) 179 ir->a1_users[i] = NULL; 180 } 181 182 for (i = 0; i < ir->predicates_count; i++) { 183 struct ir3_instruction *instr = ir->predicates[i]; 184 if (instr && (instr->flags & IR3_INSTR_UNUSED)) 185 ir->predicates[i] = NULL; 186 } 187 188 /* cleanup unused inputs: */ 189 foreach_input_n (in, n, ir) 190 if (in->flags & IR3_INSTR_UNUSED) 191 ir->inputs[n] = NULL; 192 193 return progress; 194} 195 196bool 197ir3_dce(struct ir3 *ir, struct ir3_shader_variant *so) 198{ 199 void *mem_ctx = ralloc_context(NULL); 200 bool progress, made_progress = false; 201 202 ir3_find_ssa_uses(ir, mem_ctx, true); 203 204 do { 205 progress = find_and_remove_unused(ir, so); 206 made_progress |= progress; 207 } while (progress); 208 209 ralloc_free(mem_ctx); 210 211 return made_progress; 212} 213