src/gallium/drivers/ilo/shader/toy_optimize.c

   1 /*
   2  * Mesa 3-D graphics library
   3  *
   4  * Copyright (C) 2012-2013 LunarG, Inc.
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a
   7  * copy of this software and associated documentation files (the "Software"),
   8  * to deal in the Software without restriction, including without limitation
   9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  10  * and/or sell copies of the Software, and to permit persons to whom the
  11  * Software is furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included
  14  * in all copies or substantial portions of the 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
  21  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  22  * DEALINGS IN THE SOFTWARE.
  23  *
  24  * Authors:
  25  *    Chia-I Wu <olv@lunarg.com>
  26  */
  27
  28 #include "toy_compiler.h"
  29 #include "toy_tgsi.h"
  30 #include "toy_optimize.h"
  31
  32 /**
  33  * This just eliminates instructions with null dst so far.
  34  */
  35 static void
  36 eliminate_dead_code(struct toy_compiler *tc)
  37 {
  38    struct toy_inst *inst;
  39
  40    tc_head(tc);
  41    while ((inst = tc_next(tc)) != NULL) {
  42       switch (inst->opcode) {
  43       case BRW_OPCODE_IF:
  44       case BRW_OPCODE_ELSE:
  45       case BRW_OPCODE_ENDIF:
  46       case BRW_OPCODE_WHILE:
  47       case BRW_OPCODE_BREAK:
  48       case BRW_OPCODE_CONTINUE:
  49       case BRW_OPCODE_SEND:
  50       case BRW_OPCODE_SENDC:
  51       case BRW_OPCODE_NOP:
  52          /* never eliminated */
  53          break;
  54       default:
  55          if (tdst_is_null(inst->dst) || !inst->dst.writemask) {
  56             /* math is always BRW_CONDITIONAL_NONE */
  57             if ((inst->opcode == BRW_OPCODE_MATH ||
  58                  inst->cond_modifier == BRW_CONDITIONAL_NONE) &&
  59                 !inst->acc_wr_ctrl)
  60                tc_discard_inst(tc, inst);
  61          }
  62          break;
  63       }
  64    }
  65 }
  66
  67 void
  68 toy_compiler_optimize(struct toy_compiler *tc)
  69 {
  70    eliminate_dead_code(tc);
  71 }