src/panfrost/bifrost/bi_opt_dce.c

   1 /*
   2  * Copyright (C) 2018 Alyssa Rosenzweig
   3  * Copyright (C) 2019-2020 Collabora, Ltd.
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining a
   6  * copy of this software and associated documentation files (the "Software"),
   7  * to deal in the Software without restriction, including without limitation
   8  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   9  * and/or sell copies of the Software, and to permit persons to whom the
  10  * Software is furnished to do so, subject to the following conditions:
  11  *
  12  * The above copyright notice and this permission notice (including the next
  13  * paragraph) shall be included in all copies or substantial portions of the
  14  * Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  22  * SOFTWARE.
  23  */
  24
  25 #include "compiler.h"
  26 #include "util/u_memory.h"
  27
  28 bool
  29 bi_opt_dead_code_eliminate(bi_context *ctx, bi_block *block)
  30 {
  31         bool progress = false;
  32         unsigned temp_count = bi_max_temp(ctx);
  33
  34         bi_invalidate_liveness(ctx);
  35         bi_compute_liveness(ctx);
  36
  37         uint16_t *live = mem_dup(block->base.live_out, temp_count * sizeof(uint16_t));
  38
  39         bi_foreach_instr_in_block_safe_rev(block, ins) {
  40                 if (ins->dest && !(ins->dest & BIR_SPECIAL)) {
  41                         if (!live[ins->dest]) {
  42                                 bi_remove_instruction(ins);
  43                                 progress |= true;
  44                         }
  45                 }
  46
  47                 bi_liveness_ins_update(live, ins, temp_count);
  48         }
  49
  50         free(live);
  51
  52         return progress;
  53 }