src/gallium/drivers/vc4/vc4_opt_algebraic.c

   1 /*
   2  * Copyright © 2014 Broadcom
   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
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  */
  23
  24 /**
  25  * @file vc4_opt_algebraic.c
  26  *
  27  * This is the optimization pass for miscellaneous changes to instructions
  28  * where we can simplify the operation by some knowledge about the specific
  29  * operations.
  30  *
  31  * Mostly this will be a matter of turning things into MOVs so that they can
  32  * later be copy-propagated out.
  33  */
  34
  35 #include "vc4_qir.h"
  36
  37 bool
  38 qir_opt_algebraic(struct qcompile *c)
  39 {
  40         bool progress = false;
  41         struct simple_node *node;
  42         bool debug = false;
  43
  44         foreach(node, &c->instructions) {
  45                 struct qinst *inst = (struct qinst *)node;
  46
  47                 switch (inst->op) {
  48                 case QOP_CMP:
  49                         /* Turn "dst = (a < 0) ? b : b)" into "dst = b" */
  50                         if (qir_reg_equals(inst->src[1], inst->src[2])) {
  51                                 if (debug) {
  52                                         fprintf(stderr, "optimizing: ");
  53                                         qir_dump_inst(inst);
  54                                         fprintf(stderr, "\n");
  55                                 }
  56
  57                                 inst->op = QOP_MOV;
  58                                 inst->src[0] = inst->src[1];
  59                                 inst->src[1] = c->undef;
  60                                 progress = true;
  61
  62                                 if (debug) {
  63                                         fprintf(stderr, "to: ");
  64                                         qir_dump_inst(inst);
  65                                         fprintf(stderr, "\n");
  66                                 }
  67                         }
  68                         break;
  69
  70                 default:
  71                         break;
  72                 }
  73         }
  74
  75         return progress;
  76 }