1 /* 2 * Copyright 2010 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 21 * DEALINGS IN THE SOFTWARE. 22 */ 23 24 /** 25 * \file opt_algebraic.cpp 26 * 27 * Takes advantage of association, commutivity, and other algebraic 28 * properties to simplify expressions. 29 */ 30 31 #include "ir.h" 32 #include "ir_visitor.h" 33 #include "ir_rvalue_visitor.h" 34 #include "ir_optimization.h" 35 #include "glsl_types.h" 36 37 /** 38 * Visitor class for replacing expressions with ir_constant values. 39 */ 40 41 class ir_algebraic_visitor : public ir_rvalue_visitor { 42 public: 43 ir_algebraic_visitor() 44 { 45 this->progress = false; 46 this->mem_ctx = NULL; 47 } 48 49 virtual ~ir_algebraic_visitor() 50 { 51 } 52 53 ir_rvalue *handle_expression(ir_expression *ir); 54 void handle_rvalue(ir_rvalue **rvalue); 55 bool reassociate_constant(ir_expression *ir1, 56 int const_index, 57 ir_constant *constant, 58 ir_expression *ir2); 59 void reassociate_operands(ir_expression *ir1, 60 int op1, 61 ir_expression *ir2, 62 int op2); 63 ir_rvalue *swizzle_if_required(ir_expression *expr, 64 ir_rvalue *operand); 65 66 void *mem_ctx; 67 68 bool progress; 69 }; 70 71 static inline bool 72 is_vec_zero(ir_constant *ir) 73 { 74 return (ir == NULL) ? false : ir->is_zero(); 75 } 76 77 static inline bool 78 is_vec_one(ir_constant *ir) 79 { 80 return (ir == NULL) ? false : ir->is_one(); 81 } 82 83 static void 84 update_type(ir_expression *ir) 85 { 86 if (ir->operands[0]->type->is_vector()) 87 ir->type = ir->operands[0]->type; 88 else 89 ir->type = ir->operands[1]->type; 90 } 91 92 void 93 ir_algebraic_visitor::reassociate_operands(ir_expression *ir1, 94 int op1, 95 ir_expression *ir2, 96 int op2) 97 { 98 ir_rvalue *temp = ir2->operands[op2]; 99 ir2->operands[op2] = ir1->operands[op1]; 100 ir1->operands[op1] = temp; 101 102 /* Update the type of ir2. The type of ir1 won't have changed -- 103 * base types matched, and at least one of the operands of the 2 104 * binops is still a vector if any of them were. 105 */ 106 update_type(ir2); 107 108 this->progress = true; 109 } 110 111 /** 112 * Reassociates a constant down a tree of adds or multiplies. 113 * 114 * Consider (2 * (a * (b * 0.5))). We want to send up with a * b. 115 */ 116 bool 117 ir_algebraic_visitor::reassociate_constant(ir_expression *ir1, int const_index, 118 ir_constant *constant, 119 ir_expression *ir2) 120 { 121 if (!ir2 || ir1->operation != ir2->operation) 122 return false; 123 124 /* Don't want to even think about matrices. */ 125 if (ir1->operands[0]->type->is_matrix() || 126 ir1->operands[1]->type->is_matrix() || 127 ir2->operands[0]->type->is_matrix() || 128 ir2->operands[1]->type->is_matrix()) 129 return false; 130 131 ir_constant *ir2_const[2]; 132 ir2_const[0] = ir2->operands[0]->constant_expression_value(); 133 ir2_const[1] = ir2->operands[1]->constant_expression_value(); 134 135 if (ir2_const[0] && ir2_const[1]) 136 return false; 137 138 if (ir2_const[0]) { 139 reassociate_operands(ir1, const_index, ir2, 1); 140 return true; 141 } else if (ir2_const[1]) { 142 reassociate_operands(ir1, const_index, ir2, 0); 143 return true; 144 } 145 146 if (reassociate_constant(ir1, const_index, constant, 147 ir2->operands[0]->as_expression())) { 148 update_type(ir2); 149 return true; 150 } 151 152 if (reassociate_constant(ir1, const_index, constant, 153 ir2->operands[1]->as_expression())) { 154 update_type(ir2); 155 return true; 156 } 157 158 return false; 159 } 160 161 /* When eliminating an expression and just returning one of its operands, 162 * we may need to swizzle that operand out to a vector if the expression was 163 * vector type. 164 */ 165 ir_rvalue * 166 ir_algebraic_visitor::swizzle_if_required(ir_expression *expr, 167 ir_rvalue *operand) 168 { 169 if (expr->type->is_vector() && operand->type->is_scalar()) { 170 return new(mem_ctx) ir_swizzle(operand, 0, 0, 0, 0, 171 expr->type->vector_elements); 172 } else 173 return operand; 174 } 175 176 ir_rvalue * 177 ir_algebraic_visitor::handle_expression(ir_expression *ir) 178 { 179 ir_constant *op_const[2] = {NULL, NULL}; 180 ir_expression *op_expr[2] = {NULL, NULL}; 181 ir_expression *temp; 182 unsigned int i; 183 184 assert(ir->get_num_operands() <= 2); 185 for (i = 0; i < ir->get_num_operands(); i++) { 186 if (ir->operands[i]->type->is_matrix()) 187 return ir; 188 189 op_const[i] = ir->operands[i]->constant_expression_value(); 190 op_expr[i] = ir->operands[i]->as_expression(); 191 } 192 193 if (this->mem_ctx == NULL) 194 this->mem_ctx = hieralloc_parent(ir); 195 196 switch (ir->operation) { 197 case ir_unop_logic_not: { 198 enum ir_expression_operation new_op = ir_unop_logic_not; 199 200 if (op_expr[0] == NULL) 201 break; 202 203 switch (op_expr[0]->operation) { 204 case ir_binop_less: new_op = ir_binop_gequal; break; 205 case ir_binop_greater: new_op = ir_binop_lequal; break; 206 case ir_binop_lequal: new_op = ir_binop_greater; break; 207 case ir_binop_gequal: new_op = ir_binop_less; break; 208 case ir_binop_equal: new_op = ir_binop_nequal; break; 209 case ir_binop_nequal: new_op = ir_binop_equal; break; 210 case ir_binop_all_equal: new_op = ir_binop_any_nequal; break; 211 case ir_binop_any_nequal: new_op = ir_binop_all_equal; break; 212 213 default: 214 /* The default case handler is here to silence a warning from GCC. 215 */ 216 break; 217 } 218 219 if (new_op != ir_unop_logic_not) { 220 this->progress = true; 221 return new(mem_ctx) ir_expression(new_op, 222 ir->type, 223 op_expr[0]->operands[0], 224 op_expr[0]->operands[1]); 225 } 226 227 break; 228 } 229 230 case ir_binop_add: 231 if (is_vec_zero(op_const[0])) { 232 this->progress = true; 233 return swizzle_if_required(ir, ir->operands[1]); 234 } 235 if (is_vec_zero(op_const[1])) { 236 this->progress = true; 237 return swizzle_if_required(ir, ir->operands[0]); 238 } 239 240 /* Reassociate addition of constants so that we can do constant 241 * folding. 242 */ 243 if (op_const[0] && !op_const[1]) 244 reassociate_constant(ir, 0, op_const[0], 245 ir->operands[1]->as_expression()); 246 if (op_const[1] && !op_const[0]) 247 reassociate_constant(ir, 1, op_const[1], 248 ir->operands[0]->as_expression()); 249 break; 250 251 case ir_binop_sub: 252 if (is_vec_zero(op_const[0])) { 253 this->progress = true; 254 temp = new(mem_ctx) ir_expression(ir_unop_neg, 255 ir->operands[1]->type, 256 ir->operands[1], 257 NULL); 258 return swizzle_if_required(ir, temp); 259 } 260 if (is_vec_zero(op_const[1])) { 261 this->progress = true; 262 return swizzle_if_required(ir, ir->operands[0]); 263 } 264 break; 265 266 case ir_binop_mul: 267 if (is_vec_one(op_const[0])) { 268 this->progress = true; 269 return swizzle_if_required(ir, ir->operands[1]); 270 } 271 if (is_vec_one(op_const[1])) { 272 this->progress = true; 273 return swizzle_if_required(ir, ir->operands[0]); 274 } 275 276 if (is_vec_zero(op_const[0]) || is_vec_zero(op_const[1])) { 277 this->progress = true; 278 return ir_constant::zero(ir, ir->type); 279 } 280 281 /* Reassociate multiplication of constants so that we can do 282 * constant folding. 283 */ 284 if (op_const[0] && !op_const[1]) 285 reassociate_constant(ir, 0, op_const[0], 286 ir->operands[1]->as_expression()); 287 if (op_const[1] && !op_const[0]) 288 reassociate_constant(ir, 1, op_const[1], 289 ir->operands[0]->as_expression()); 290 291 break; 292 293 case ir_binop_div: 294 if (is_vec_one(op_const[0]) && ir->type->base_type == GLSL_TYPE_FLOAT) { 295 this->progress = true; 296 temp = new(mem_ctx) ir_expression(ir_unop_rcp, 297 ir->operands[1]->type, 298 ir->operands[1], 299 NULL); 300 return swizzle_if_required(ir, temp); 301 } 302 if (is_vec_one(op_const[1])) { 303 this->progress = true; 304 return swizzle_if_required(ir, ir->operands[0]); 305 } 306 break; 307 308 case ir_binop_logic_and: 309 /* FINISHME: Also simplify (a && a) to (a). */ 310 if (is_vec_one(op_const[0])) { 311 this->progress = true; 312 return ir->operands[1]; 313 } else if (is_vec_one(op_const[1])) { 314 this->progress = true; 315 return ir->operands[0]; 316 } else if (is_vec_zero(op_const[0]) || is_vec_zero(op_const[1])) { 317 this->progress = true; 318 return ir_constant::zero(mem_ctx, ir->type); 319 } 320 break; 321 322 case ir_binop_logic_xor: 323 /* FINISHME: Also simplify (a ^^ a) to (false). */ 324 if (is_vec_zero(op_const[0])) { 325 this->progress = true; 326 return ir->operands[1]; 327 } else if (is_vec_zero(op_const[1])) { 328 this->progress = true; 329 return ir->operands[0]; 330 } else if (is_vec_one(op_const[0])) { 331 this->progress = true; 332 return new(mem_ctx) ir_expression(ir_unop_logic_not, ir->type, 333 ir->operands[1], NULL); 334 } else if (is_vec_one(op_const[1])) { 335 this->progress = true; 336 return new(mem_ctx) ir_expression(ir_unop_logic_not, ir->type, 337 ir->operands[0], NULL); 338 } 339 break; 340 341 case ir_binop_logic_or: 342 /* FINISHME: Also simplify (a || a) to (a). */ 343 if (is_vec_zero(op_const[0])) { 344 this->progress = true; 345 return ir->operands[1]; 346 } else if (is_vec_zero(op_const[1])) { 347 this->progress = true; 348 return ir->operands[0]; 349 } else if (is_vec_one(op_const[0]) || is_vec_one(op_const[1])) { 350 ir_constant_data data; 351 352 for (unsigned i = 0; i < 16; i++) 353 data.b[i] = true; 354 355 this->progress = true; 356 return new(mem_ctx) ir_constant(ir->type, &data); 357 } 358 break; 359 360 case ir_unop_rcp: 361 if (op_expr[0] && op_expr[0]->operation == ir_unop_rcp) { 362 this->progress = true; 363 return op_expr[0]->operands[0]; 364 } 365 366 /* FINISHME: We should do rcp(rsq(x)) -> sqrt(x) for some 367 * backends, except that some backends will have done sqrt -> 368 * rcp(rsq(x)) and we don't want to undo it for them. 369 */ 370 371 /* As far as we know, all backends are OK with rsq. */ 372 if (op_expr[0] && op_expr[0]->operation == ir_unop_sqrt) { 373 this->progress = true; 374 temp = new(mem_ctx) ir_expression(ir_unop_rsq, 375 op_expr[0]->operands[0]->type, 376 op_expr[0]->operands[0], 377 NULL); 378 return swizzle_if_required(ir, temp); 379 } 380 381 break; 382 383 default: 384 break; 385 } 386 387 return ir; 388 } 389 390 void 391 ir_algebraic_visitor::handle_rvalue(ir_rvalue **rvalue) 392 { 393 if (!*rvalue) 394 return; 395 396 ir_expression *expr = (*rvalue)->as_expression(); 397 if (!expr || expr->operation == ir_quadop_vector) 398 return; 399 400 *rvalue = handle_expression(expr); 401 } 402 403 bool 404 do_algebraic(exec_list *instructions) 405 { 406 ir_algebraic_visitor v; 407 408 visit_list_elements(&v, instructions); 409 410 return v.progress; 411 } 412
