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 #include "util/u_math.h"
  37
  38 static bool debug;
  39
  40 static void
  41 dump_from(struct vc4_compile *c, struct qinst *inst)
  42 {
  43         if (!debug)
  44                 return;
  45
  46         fprintf(stderr, "optimizing: ");
  47         qir_dump_inst(c, inst);
  48         fprintf(stderr, "\n");
  49 }
  50
  51 static void
  52 dump_to(struct vc4_compile *c, struct qinst *inst)
  53 {
  54         if (!debug)
  55                 return;
  56
  57         fprintf(stderr, "to: ");
  58         qir_dump_inst(c, inst);
  59         fprintf(stderr, "\n");
  60 }
  61
  62 static bool
  63 is_constant_value(struct vc4_compile *c, struct qreg reg,
  64                   uint32_t val)
  65 {
  66         if (reg.file == QFILE_UNIF &&
  67             !reg.pack &&
  68             c->uniform_contents[reg.index] == QUNIFORM_CONSTANT &&
  69             c->uniform_data[reg.index] == val) {
  70                 return true;
  71         }
  72
  73         if (reg.file == QFILE_SMALL_IMM && reg.index == val)
  74                 return true;
  75
  76         return false;
  77 }
  78
  79 static bool
  80 is_zero(struct vc4_compile *c, struct qreg reg)
  81 {
  82         reg = qir_follow_movs(c, reg);
  83         return is_constant_value(c, reg, 0);
  84 }
  85
  86 static bool
  87 is_1f(struct vc4_compile *c, struct qreg reg)
  88 {
  89         reg = qir_follow_movs(c, reg);
  90         return is_constant_value(c, reg, fui(1.0));
  91 }
  92
  93 static void
  94 replace_with_mov(struct vc4_compile *c, struct qinst *inst, struct qreg arg)
  95 {
  96         dump_from(c, inst);
  97
  98         inst->src[0] = arg;
  99         if (qir_has_implicit_tex_uniform(inst))
 100                 inst->src[1] = inst->src[qir_get_tex_uniform_src(inst)];
 101
 102         if (qir_is_mul(inst))
 103                 inst->op = QOP_MMOV;
 104         else if (qir_is_float_input(inst))
 105                 inst->op = QOP_FMOV;
 106         else
 107                 inst->op = QOP_MOV;
 108         dump_to(c, inst);
 109 }
 110
 111 static bool
 112 replace_x_0_with_x(struct vc4_compile *c,
 113                  struct qinst *inst,
 114                  int arg)
 115 {
 116         if (!is_zero(c, inst->src[arg]))
 117                 return false;
 118         replace_with_mov(c, inst, inst->src[1 - arg]);
 119         return true;
 120 }
 121
 122 static bool
 123 replace_x_0_with_0(struct vc4_compile *c,
 124                   struct qinst *inst,
 125                   int arg)
 126 {
 127         if (!is_zero(c, inst->src[arg]))
 128                 return false;
 129         replace_with_mov(c, inst, inst->src[arg]);
 130         return true;
 131 }
 132
 133 static bool
 134 fmul_replace_one(struct vc4_compile *c,
 135                  struct qinst *inst,
 136                  int arg)
 137 {
 138         if (!is_1f(c, inst->src[arg]))
 139                 return false;
 140         replace_with_mov(c, inst, inst->src[1 - arg]);
 141         return true;
 142 }
 143
 144 bool
 145 qir_opt_algebraic(struct vc4_compile *c)
 146 {
 147         bool progress = false;
 148
 149         qir_for_each_inst_inorder(inst, c) {
 150                 switch (inst->op) {
 151                 case QOP_FMIN:
 152                         if (is_1f(c, inst->src[1]) &&
 153                             inst->src[0].pack >= QPU_UNPACK_8D_REP &&
 154                             inst->src[0].pack <= QPU_UNPACK_8D) {
 155                                 replace_with_mov(c, inst, inst->src[0]);
 156                                 progress = true;
 157                         }
 158                         break;
 159
 160                 case QOP_FMAX:
 161                         if (is_zero(c, inst->src[1]) &&
 162                             inst->src[0].pack >= QPU_UNPACK_8D_REP &&
 163                             inst->src[0].pack <= QPU_UNPACK_8D) {
 164                                 replace_with_mov(c, inst, inst->src[0]);
 165                                 progress = true;
 166                         }
 167                         break;
 168
 169                 case QOP_FSUB:
 170                 case QOP_SUB:
 171                         if (is_zero(c, inst->src[1])) {
 172                                 replace_with_mov(c, inst, inst->src[0]);
 173                                 progress = true;
 174                         }
 175                         break;
 176
 177                 case QOP_ADD:
 178                         /* Kernel validation requires that we use an actual
 179                          * add instruction.
 180                          */
 181                         if (inst->dst.file != QFILE_TEX_S_DIRECT &&
 182                             (replace_x_0_with_x(c, inst, 0) ||
 183                              replace_x_0_with_x(c, inst, 1))) {
 184                                 progress = true;
 185                                 break;
 186                         }
 187                         break;
 188
 189                 case QOP_FADD:
 190                         if (replace_x_0_with_x(c, inst, 0) ||
 191                             replace_x_0_with_x(c, inst, 1)) {
 192                                 progress = true;
 193                                 break;
 194                         }
 195
 196                         /* FADD(a, FSUB(0, b)) -> FSUB(a, b) */
 197                         if (inst->src[1].file == QFILE_TEMP &&
 198                             c->defs[inst->src[1].index] &&
 199                             c->defs[inst->src[1].index]->op == QOP_FSUB) {
 200                                 struct qinst *fsub = c->defs[inst->src[1].index];
 201                                 if (is_zero(c, fsub->src[0])) {
 202                                         dump_from(c, inst);
 203                                         inst->op = QOP_FSUB;
 204                                         inst->src[1] = fsub->src[1];
 205                                         progress = true;
 206                                         dump_to(c, inst);
 207                                         break;
 208                                 }
 209                         }
 210
 211                         /* FADD(FSUB(0, b), a) -> FSUB(a, b) */
 212                         if (inst->src[0].file == QFILE_TEMP &&
 213                             c->defs[inst->src[0].index] &&
 214                             c->defs[inst->src[0].index]->op == QOP_FSUB) {
 215                                 struct qinst *fsub = c->defs[inst->src[0].index];
 216                                 if (is_zero(c, fsub->src[0])) {
 217                                         dump_from(c, inst);
 218                                         inst->op = QOP_FSUB;
 219                                         inst->src[0] = inst->src[1];
 220                                         inst->src[1] = fsub->src[1];
 221                                         dump_to(c, inst);
 222                                         progress = true;
 223                                         break;
 224                                 }
 225                         }
 226                         break;
 227
 228                 case QOP_FMUL:
 229                         if (!inst->dst.pack &&
 230                             (replace_x_0_with_0(c, inst, 0) ||
 231                              replace_x_0_with_0(c, inst, 1) ||
 232                              fmul_replace_one(c, inst, 0) ||
 233                              fmul_replace_one(c, inst, 1))) {
 234                                 progress = true;
 235                                 break;
 236                         }
 237                         break;
 238
 239                 case QOP_MUL24:
 240                         if (!inst->dst.pack &&
 241                             (replace_x_0_with_0(c, inst, 0) ||
 242                              replace_x_0_with_0(c, inst, 1))) {
 243                                 progress = true;
 244                                 break;
 245                         }
 246                         break;
 247
 248                 case QOP_AND:
 249                         if (replace_x_0_with_0(c, inst, 0) ||
 250                             replace_x_0_with_0(c, inst, 1)) {
 251                                 progress = true;
 252                                 break;
 253                         }
 254
 255                         if (is_constant_value(c, inst->src[0], ~0)) {
 256                                 replace_with_mov(c, inst, inst->src[1]);
 257                                 progress = true;
 258                                 break;
 259                         }
 260                         if (is_constant_value(c, inst->src[1], ~0)) {
 261                                 replace_with_mov(c, inst, inst->src[0]);
 262                                 progress = true;
 263                                 break;
 264                         }
 265                         break;
 266
 267                 case QOP_OR:
 268                         if (replace_x_0_with_x(c, inst, 0) ||
 269                             replace_x_0_with_x(c, inst, 1)) {
 270                                 progress = true;
 271                                 break;
 272                         }
 273                         break;
 274
 275                 case QOP_RCP:
 276                         if (is_1f(c, inst->src[0])) {
 277                                 replace_with_mov(c, inst, inst->src[0]);
 278                                 progress = true;
 279                                 break;
 280                         }
 281                         break;
 282
 283                 default:
 284                         break;
 285                 }
 286         }
 287
 288         return progress;
 289 }