src/glsl/nir/nir_search.c

   1 /*
   2  * Copyright © 2014 Intel Corporation
   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  * Authors:
  24  *    Jason Ekstrand (jason@jlekstrand.net)
  25  *
  26  */
  27
  28 #include "nir_search.h"
  29
  30 struct match_state {
  31    unsigned variables_seen;
  32    nir_alu_src variables[NIR_SEARCH_MAX_VARIABLES];
  33 };
  34
  35 static bool
  36 match_expression(const nir_search_expression *expr, nir_alu_instr *instr,
  37                  unsigned num_components, const uint8_t *swizzle,
  38                  struct match_state *state);
  39
  40 static const uint8_t identity_swizzle[] = { 0, 1, 2, 3 };
  41
  42 static bool alu_instr_is_bool(nir_alu_instr *instr);
  43
  44 static bool
  45 src_is_bool(nir_src src)
  46 {
  47    if (!src.is_ssa)
  48       return false;
  49    if (src.ssa->parent_instr->type != nir_instr_type_alu)
  50       return false;
  51    return alu_instr_is_bool((nir_alu_instr *)src.ssa->parent_instr);
  52 }
  53
  54 static bool
  55 alu_instr_is_bool(nir_alu_instr *instr)
  56 {
  57    switch (instr->op) {
  58    case nir_op_iand:
  59    case nir_op_ior:
  60    case nir_op_ixor:
  61       return src_is_bool(instr->src[0].src) && src_is_bool(instr->src[1].src);
  62    case nir_op_inot:
  63       return src_is_bool(instr->src[0].src);
  64    default:
  65       return nir_op_infos[instr->op].output_type == nir_type_bool;
  66    }
  67 }
  68
  69 static bool
  70 match_value(const nir_search_value *value, nir_alu_instr *instr, unsigned src,
  71             unsigned num_components, const uint8_t *swizzle,
  72             struct match_state *state)
  73 {
  74    uint8_t new_swizzle[4];
  75
  76    /* If the source is an explicitly sized source, then we need to reset
  77     * both the number of components and the swizzle.
  78     */
  79    if (nir_op_infos[instr->op].input_sizes[src] != 0) {
  80       num_components = nir_op_infos[instr->op].input_sizes[src];
  81       swizzle = identity_swizzle;
  82    }
  83
  84    for (int i = 0; i < num_components; ++i)
  85       new_swizzle[i] = instr->src[src].swizzle[swizzle[i]];
  86
  87    switch (value->type) {
  88    case nir_search_value_expression:
  89       if (!instr->src[src].src.is_ssa)
  90          return false;
  91
  92       if (instr->src[src].src.ssa->parent_instr->type != nir_instr_type_alu)
  93          return false;
  94
  95       return match_expression(nir_search_value_as_expression(value),
  96                               nir_instr_as_alu(instr->src[src].src.ssa->parent_instr),
  97                               num_components, new_swizzle, state);
  98
  99    case nir_search_value_variable: {
 100       nir_search_variable *var = nir_search_value_as_variable(value);
 101
 102       if (state->variables_seen & (1 << var->variable)) {
 103          if (!nir_srcs_equal(state->variables[var->variable].src,
 104                              instr->src[src].src))
 105             return false;
 106
 107          assert(!instr->src[src].abs && !instr->src[src].negate);
 108
 109          for (int i = 0; i < num_components; ++i) {
 110             if (state->variables[var->variable].swizzle[i] != new_swizzle[i])
 111                return false;
 112          }
 113
 114          return true;
 115       } else {
 116          if (var->is_constant &&
 117              instr->src[src].src.ssa->parent_instr->type != nir_instr_type_load_const)
 118             return false;
 119
 120          if (var->type != nir_type_invalid) {
 121             if (instr->src[src].src.ssa->parent_instr->type != nir_instr_type_alu)
 122                return false;
 123
 124             nir_alu_instr *src_alu =
 125                nir_instr_as_alu(instr->src[src].src.ssa->parent_instr);
 126
 127             if (nir_op_infos[src_alu->op].output_type != var->type &&
 128                 !(var->type == nir_type_bool && alu_instr_is_bool(src_alu)))
 129                return false;
 130          }
 131
 132          state->variables_seen |= (1 << var->variable);
 133          state->variables[var->variable].src = instr->src[src].src;
 134          state->variables[var->variable].abs = false;
 135          state->variables[var->variable].negate = false;
 136
 137          for (int i = 0; i < 4; ++i) {
 138             if (i < num_components)
 139                state->variables[var->variable].swizzle[i] = new_swizzle[i];
 140             else
 141                state->variables[var->variable].swizzle[i] = 0;
 142          }
 143
 144          return true;
 145       }
 146    }
 147
 148    case nir_search_value_constant: {
 149       nir_search_constant *const_val = nir_search_value_as_constant(value);
 150
 151       if (!instr->src[src].src.is_ssa)
 152          return false;
 153
 154       if (instr->src[src].src.ssa->parent_instr->type != nir_instr_type_load_const)
 155          return false;
 156
 157       nir_load_const_instr *load =
 158          nir_instr_as_load_const(instr->src[src].src.ssa->parent_instr);
 159
 160       switch (nir_op_infos[instr->op].input_types[src]) {
 161       case nir_type_float:
 162          for (unsigned i = 0; i < num_components; ++i) {
 163             if (load->value.f[new_swizzle[i]] != const_val->data.f)
 164                return false;
 165          }
 166          return true;
 167       case nir_type_int:
 168       case nir_type_unsigned:
 169       case nir_type_bool:
 170          for (unsigned i = 0; i < num_components; ++i) {
 171             if (load->value.i[new_swizzle[i]] != const_val->data.i)
 172                return false;
 173          }
 174          return true;
 175       default:
 176          unreachable("Invalid alu source type");
 177       }
 178    }
 179
 180    default:
 181       unreachable("Invalid search value type");
 182    }
 183 }
 184
 185 static bool
 186 match_expression(const nir_search_expression *expr, nir_alu_instr *instr,
 187                  unsigned num_components, const uint8_t *swizzle,
 188                  struct match_state *state)
 189 {
 190    if (instr->op != expr->opcode)
 191       return false;
 192
 193    assert(!instr->dest.saturate);
 194    assert(nir_op_infos[instr->op].num_inputs > 0);
 195
 196    /* If we have an explicitly sized destination, we can only handle the
 197     * identity swizzle.  While dot(vec3(a, b, c).zxy) is a valid
 198     * expression, we don't have the information right now to propagate that
 199     * swizzle through.  We can only properly propagate swizzles if the
 200     * instruction is vectorized.
 201     */
 202    if (nir_op_infos[instr->op].output_size != 0) {
 203       for (unsigned i = 0; i < num_components; i++) {
 204          if (swizzle[i] != i)
 205             return false;
 206       }
 207    }
 208
 209    bool matched = true;
 210    for (unsigned i = 0; i < nir_op_infos[instr->op].num_inputs; i++) {
 211       if (!match_value(expr->srcs[i], instr, i, num_components,
 212                        swizzle, state)) {
 213          matched = false;
 214          break;
 215       }
 216    }
 217
 218    if (matched)
 219       return true;
 220
 221    if (nir_op_infos[instr->op].algebraic_properties & NIR_OP_IS_COMMUTATIVE) {
 222       assert(nir_op_infos[instr->op].num_inputs == 2);
 223       if (!match_value(expr->srcs[0], instr, 1, num_components,
 224                        swizzle, state))
 225          return false;
 226
 227       return match_value(expr->srcs[1], instr, 0, num_components,
 228                          swizzle, state);
 229    } else {
 230       return false;
 231    }
 232 }
 233
 234 static nir_alu_src
 235 construct_value(const nir_search_value *value, nir_alu_type type,
 236                 unsigned num_components, struct match_state *state,
 237                 nir_instr *instr, void *mem_ctx)
 238 {
 239    switch (value->type) {
 240    case nir_search_value_expression: {
 241       const nir_search_expression *expr = nir_search_value_as_expression(value);
 242
 243       if (nir_op_infos[expr->opcode].output_size != 0)
 244          num_components = nir_op_infos[expr->opcode].output_size;
 245
 246       nir_alu_instr *alu = nir_alu_instr_create(mem_ctx, expr->opcode);
 247       nir_ssa_dest_init(&alu->instr, &alu->dest.dest, num_components, NULL);
 248       alu->dest.write_mask = (1 << num_components) - 1;
 249       alu->dest.saturate = false;
 250
 251       for (unsigned i = 0; i < nir_op_infos[expr->opcode].num_inputs; i++) {
 252          /* If the source is an explicitly sized source, then we need to reset
 253           * the number of components to match.
 254           */
 255          if (nir_op_infos[alu->op].input_sizes[i] != 0)
 256             num_components = nir_op_infos[alu->op].input_sizes[i];
 257
 258          alu->src[i] = construct_value(expr->srcs[i],
 259                                        nir_op_infos[alu->op].input_types[i],
 260                                        num_components,
 261                                        state, instr, mem_ctx);
 262       }
 263
 264       nir_instr_insert_before(instr, &alu->instr);
 265
 266       nir_alu_src val;
 267       val.src = nir_src_for_ssa(&alu->dest.dest.ssa);
 268       val.negate = false;
 269       val.abs = false,
 270       memcpy(val.swizzle, identity_swizzle, sizeof val.swizzle);
 271
 272       return val;
 273    }
 274
 275    case nir_search_value_variable: {
 276       const nir_search_variable *var = nir_search_value_as_variable(value);
 277       assert(state->variables_seen & (1 << var->variable));
 278
 279       nir_alu_src val = { NIR_SRC_INIT };
 280       nir_alu_src_copy(&val, &state->variables[var->variable], mem_ctx);
 281
 282       assert(!var->is_constant);
 283
 284       return val;
 285    }
 286
 287    case nir_search_value_constant: {
 288       const nir_search_constant *c = nir_search_value_as_constant(value);
 289       nir_load_const_instr *load = nir_load_const_instr_create(mem_ctx, 1);
 290
 291       switch (type) {
 292       case nir_type_float:
 293          load->def.name = ralloc_asprintf(mem_ctx, "%f", c->data.f);
 294          load->value.f[0] = c->data.f;
 295          break;
 296       case nir_type_int:
 297          load->def.name = ralloc_asprintf(mem_ctx, "%d", c->data.i);
 298          load->value.i[0] = c->data.i;
 299          break;
 300       case nir_type_unsigned:
 301       case nir_type_bool:
 302          load->value.u[0] = c->data.u;
 303          break;
 304       default:
 305          unreachable("Invalid alu source type");
 306       }
 307
 308       nir_instr_insert_before(instr, &load->instr);
 309
 310       nir_alu_src val;
 311       val.src = nir_src_for_ssa(&load->def);
 312       val.negate = false;
 313       val.abs = false,
 314       memset(val.swizzle, 0, sizeof val.swizzle);
 315
 316       return val;
 317    }
 318
 319    default:
 320       unreachable("Invalid search value type");
 321    }
 322 }
 323
 324 nir_alu_instr *
 325 nir_replace_instr(nir_alu_instr *instr, const nir_search_expression *search,
 326                   const nir_search_value *replace, void *mem_ctx)
 327 {
 328    uint8_t swizzle[4] = { 0, 0, 0, 0 };
 329
 330    for (unsigned i = 0; i < instr->dest.dest.ssa.num_components; ++i)
 331       swizzle[i] = i;
 332
 333    assert(instr->dest.dest.is_ssa);
 334
 335    struct match_state state;
 336    state.variables_seen = 0;
 337
 338    if (!match_expression(search, instr, instr->dest.dest.ssa.num_components,
 339                          swizzle, &state))
 340       return NULL;
 341
 342    /* Inserting a mov may be unnecessary.  However, it's much easier to
 343     * simply let copy propagation clean this up than to try to go through
 344     * and rewrite swizzles ourselves.
 345     */
 346    nir_alu_instr *mov = nir_alu_instr_create(mem_ctx, nir_op_imov);
 347    mov->dest.write_mask = instr->dest.write_mask;
 348    nir_ssa_dest_init(&mov->instr, &mov->dest.dest,
 349                      instr->dest.dest.ssa.num_components, NULL);
 350
 351    mov->src[0] = construct_value(replace, nir_op_infos[instr->op].output_type,
 352                                  instr->dest.dest.ssa.num_components, &state,
 353                                  &instr->instr, mem_ctx);
 354    nir_instr_insert_before(&instr->instr, &mov->instr);
 355
 356    nir_ssa_def_rewrite_uses(&instr->dest.dest.ssa,
 357                             nir_src_for_ssa(&mov->dest.dest.ssa), mem_ctx);
 358
 359    /* We know this one has no more uses because we just rewrote them all,
 360     * so we can remove it.  The rest of the matched expression, however, we
 361     * don't know so much about.  We'll just let dead code clean them up.
 362     */
 363    nir_instr_remove(&instr->instr);
 364
 365    return mov;
 366 }