| 1 | /* Global, SSA-based optimizations using mathematical identities. |
| 2 | Copyright (C) 2005, 2006, 2007, 2008 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of GCC. |
| 5 | |
| 6 | GCC is free software; you can redistribute it and/or modify it |
| 7 | under the terms of the GNU General Public License as published by the |
| 8 | Free Software Foundation; either version 3, or (at your option) any |
| 9 | later version. |
| 10 | |
| 11 | GCC is distributed in the hope that it will be useful, but WITHOUT |
| 12 | ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with GCC; see the file COPYING3. If not see |
| 18 | <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | /* Currently, the only mini-pass in this file tries to CSE reciprocal |
| 21 | operations. These are common in sequences such as this one: |
| 22 | |
| 23 | modulus = sqrt(x*x + y*y + z*z); |
| 24 | x = x / modulus; |
| 25 | y = y / modulus; |
| 26 | z = z / modulus; |
| 27 | |
| 28 | that can be optimized to |
| 29 | |
| 30 | modulus = sqrt(x*x + y*y + z*z); |
| 31 | rmodulus = 1.0 / modulus; |
| 32 | x = x * rmodulus; |
| 33 | y = y * rmodulus; |
| 34 | z = z * rmodulus; |
| 35 | |
| 36 | We do this for loop invariant divisors, and with this pass whenever |
| 37 | we notice that a division has the same divisor multiple times. |
| 38 | |
| 39 | Of course, like in PRE, we don't insert a division if a dominator |
| 40 | already has one. However, this cannot be done as an extension of |
| 41 | PRE for several reasons. |
| 42 | |
| 43 | First of all, with some experiments it was found out that the |
| 44 | transformation is not always useful if there are only two divisions |
| 45 | hy the same divisor. This is probably because modern processors |
| 46 | can pipeline the divisions; on older, in-order processors it should |
| 47 | still be effective to optimize two divisions by the same number. |
| 48 | We make this a param, and it shall be called N in the remainder of |
| 49 | this comment. |
| 50 | |
| 51 | Second, if trapping math is active, we have less freedom on where |
| 52 | to insert divisions: we can only do so in basic blocks that already |
| 53 | contain one. (If divisions don't trap, instead, we can insert |
| 54 | divisions elsewhere, which will be in blocks that are common dominators |
| 55 | of those that have the division). |
| 56 | |
| 57 | We really don't want to compute the reciprocal unless a division will |
| 58 | be found. To do this, we won't insert the division in a basic block |
| 59 | that has less than N divisions *post-dominating* it. |
| 60 | |
| 61 | The algorithm constructs a subset of the dominator tree, holding the |
| 62 | blocks containing the divisions and the common dominators to them, |
| 63 | and walk it twice. The first walk is in post-order, and it annotates |
| 64 | each block with the number of divisions that post-dominate it: this |
| 65 | gives information on where divisions can be inserted profitably. |
| 66 | The second walk is in pre-order, and it inserts divisions as explained |
| 67 | above, and replaces divisions by multiplications. |
| 68 | |
| 69 | In the best case, the cost of the pass is O(n_statements). In the |
| 70 | worst-case, the cost is due to creating the dominator tree subset, |
| 71 | with a cost of O(n_basic_blocks ^ 2); however this can only happen |
| 72 | for n_statements / n_basic_blocks statements. So, the amortized cost |
| 73 | of creating the dominator tree subset is O(n_basic_blocks) and the |
| 74 | worst-case cost of the pass is O(n_statements * n_basic_blocks). |
| 75 | |
| 76 | More practically, the cost will be small because there are few |
| 77 | divisions, and they tend to be in the same basic block, so insert_bb |
| 78 | is called very few times. |
| 79 | |
| 80 | If we did this using domwalk.c, an efficient implementation would have |
| 81 | to work on all the variables in a single pass, because we could not |
| 82 | work on just a subset of the dominator tree, as we do now, and the |
| 83 | cost would also be something like O(n_statements * n_basic_blocks). |
| 84 | The data structures would be more complex in order to work on all the |
| 85 | variables in a single pass. */ |
| 86 | |
| 87 | #include "config.h" |
| 88 | #include "system.h" |
| 89 | #include "coretypes.h" |
| 90 | #include "tm.h" |
| 91 | #include "flags.h" |
| 92 | #include "tree.h" |
| 93 | #include "tree-flow.h" |
| 94 | #include "real.h" |
| 95 | #include "timevar.h" |
| 96 | #include "tree-pass.h" |
| 97 | #include "alloc-pool.h" |
| 98 | #include "basic-block.h" |
| 99 | #include "target.h" |
| 100 | |
| 101 | |
| 102 | /* This structure represents one basic block that either computes a |
| 103 | division, or is a common dominator for basic block that compute a |
| 104 | division. */ |
| 105 | struct occurrence { |
| 106 | /* The basic block represented by this structure. */ |
| 107 | basic_block bb; |
| 108 | |
| 109 | /* If non-NULL, the SSA_NAME holding the definition for a reciprocal |
| 110 | inserted in BB. */ |
| 111 | tree recip_def; |
| 112 | |
| 113 | /* If non-NULL, the GIMPLE_ASSIGN for a reciprocal computation that |
| 114 | was inserted in BB. */ |
| 115 | gimple recip_def_stmt; |
| 116 | |
| 117 | /* Pointer to a list of "struct occurrence"s for blocks dominated |
| 118 | by BB. */ |
| 119 | struct occurrence *children; |
| 120 | |
| 121 | /* Pointer to the next "struct occurrence"s in the list of blocks |
| 122 | sharing a common dominator. */ |
| 123 | struct occurrence *next; |
| 124 | |
| 125 | /* The number of divisions that are in BB before compute_merit. The |
| 126 | number of divisions that are in BB or post-dominate it after |
| 127 | compute_merit. */ |
| 128 | int num_divisions; |
| 129 | |
| 130 | /* True if the basic block has a division, false if it is a common |
| 131 | dominator for basic blocks that do. If it is false and trapping |
| 132 | math is active, BB is not a candidate for inserting a reciprocal. */ |
| 133 | bool bb_has_division; |
| 134 | }; |
| 135 | |
| 136 | |
| 137 | /* The instance of "struct occurrence" representing the highest |
| 138 | interesting block in the dominator tree. */ |
| 139 | static struct occurrence *occ_head; |
| 140 | |
| 141 | /* Allocation pool for getting instances of "struct occurrence". */ |
| 142 | static alloc_pool occ_pool; |
| 143 | |
| 144 | |
| 145 | |
| 146 | /* Allocate and return a new struct occurrence for basic block BB, and |
| 147 | whose children list is headed by CHILDREN. */ |
| 148 | static struct occurrence * |
| 149 | occ_new (basic_block bb, struct occurrence *children) |
| 150 | { |
| 151 | struct occurrence *occ; |
| 152 | |
| 153 | bb->aux = occ = (struct occurrence *) pool_alloc (occ_pool); |
| 154 | memset (occ, 0, sizeof (struct occurrence)); |
| 155 | |
| 156 | occ->bb = bb; |
| 157 | occ->children = children; |
| 158 | return occ; |
| 159 | } |
| 160 | |
| 161 | |
| 162 | /* Insert NEW_OCC into our subset of the dominator tree. P_HEAD points to a |
| 163 | list of "struct occurrence"s, one per basic block, having IDOM as |
| 164 | their common dominator. |
| 165 | |
| 166 | We try to insert NEW_OCC as deep as possible in the tree, and we also |
| 167 | insert any other block that is a common dominator for BB and one |
| 168 | block already in the tree. */ |
| 169 | |
| 170 | static void |
| 171 | insert_bb (struct occurrence *new_occ, basic_block idom, |
| 172 | struct occurrence **p_head) |
| 173 | { |
| 174 | struct occurrence *occ, **p_occ; |
| 175 | |
| 176 | for (p_occ = p_head; (occ = *p_occ) != NULL; ) |
| 177 | { |
| 178 | basic_block bb = new_occ->bb, occ_bb = occ->bb; |
| 179 | basic_block dom = nearest_common_dominator (CDI_DOMINATORS, occ_bb, bb); |
| 180 | if (dom == bb) |
| 181 | { |
| 182 | /* BB dominates OCC_BB. OCC becomes NEW_OCC's child: remove OCC |
| 183 | from its list. */ |
| 184 | *p_occ = occ->next; |
| 185 | occ->next = new_occ->children; |
| 186 | new_occ->children = occ; |
| 187 | |
| 188 | /* Try the next block (it may as well be dominated by BB). */ |
| 189 | } |
| 190 | |
| 191 | else if (dom == occ_bb) |
| 192 | { |
| 193 | /* OCC_BB dominates BB. Tail recurse to look deeper. */ |
| 194 | insert_bb (new_occ, dom, &occ->children); |
| 195 | return; |
| 196 | } |
| 197 | |
| 198 | else if (dom != idom) |
| 199 | { |
| 200 | gcc_assert (!dom->aux); |
| 201 | |
| 202 | /* There is a dominator between IDOM and BB, add it and make |
| 203 | two children out of NEW_OCC and OCC. First, remove OCC from |
| 204 | its list. */ |
| 205 | *p_occ = occ->next; |
| 206 | new_occ->next = occ; |
| 207 | occ->next = NULL; |
| 208 | |
| 209 | /* None of the previous blocks has DOM as a dominator: if we tail |
| 210 | recursed, we would reexamine them uselessly. Just switch BB with |
| 211 | DOM, and go on looking for blocks dominated by DOM. */ |
| 212 | new_occ = occ_new (dom, new_occ); |
| 213 | } |
| 214 | |
| 215 | else |
| 216 | { |
| 217 | /* Nothing special, go on with the next element. */ |
| 218 | p_occ = &occ->next; |
| 219 | } |
| 220 | } |
| 221 | |
| 222 | /* No place was found as a child of IDOM. Make BB a sibling of IDOM. */ |
| 223 | new_occ->next = *p_head; |
| 224 | *p_head = new_occ; |
| 225 | } |
| 226 | |
| 227 | /* Register that we found a division in BB. */ |
| 228 | |
| 229 | static inline void |
| 230 | register_division_in (basic_block bb) |
| 231 | { |
| 232 | struct occurrence *occ; |
| 233 | |
| 234 | occ = (struct occurrence *) bb->aux; |
| 235 | if (!occ) |
| 236 | { |
| 237 | occ = occ_new (bb, NULL); |
| 238 | insert_bb (occ, ENTRY_BLOCK_PTR, &occ_head); |
| 239 | } |
| 240 | |
| 241 | occ->bb_has_division = true; |
| 242 | occ->num_divisions++; |
| 243 | } |
| 244 | |
| 245 | |
| 246 | /* Compute the number of divisions that postdominate each block in OCC and |
| 247 | its children. */ |
| 248 | |
| 249 | static void |
| 250 | compute_merit (struct occurrence *occ) |
| 251 | { |
| 252 | struct occurrence *occ_child; |
| 253 | basic_block dom = occ->bb; |
| 254 | |
| 255 | for (occ_child = occ->children; occ_child; occ_child = occ_child->next) |
| 256 | { |
| 257 | basic_block bb; |
| 258 | if (occ_child->children) |
| 259 | compute_merit (occ_child); |
| 260 | |
| 261 | if (flag_exceptions) |
| 262 | bb = single_noncomplex_succ (dom); |
| 263 | else |
| 264 | bb = dom; |
| 265 | |
| 266 | if (dominated_by_p (CDI_POST_DOMINATORS, bb, occ_child->bb)) |
| 267 | occ->num_divisions += occ_child->num_divisions; |
| 268 | } |
| 269 | } |
| 270 | |
| 271 | |
| 272 | /* Return whether USE_STMT is a floating-point division by DEF. */ |
| 273 | static inline bool |
| 274 | is_division_by (gimple use_stmt, tree def) |
| 275 | { |
| 276 | return is_gimple_assign (use_stmt) |
| 277 | && gimple_assign_rhs_code (use_stmt) == RDIV_EXPR |
| 278 | && gimple_assign_rhs2 (use_stmt) == def |
| 279 | /* Do not recognize x / x as valid division, as we are getting |
| 280 | confused later by replacing all immediate uses x in such |
| 281 | a stmt. */ |
| 282 | && gimple_assign_rhs1 (use_stmt) != def; |
| 283 | } |
| 284 | |
| 285 | /* Walk the subset of the dominator tree rooted at OCC, setting the |
| 286 | RECIP_DEF field to a definition of 1.0 / DEF that can be used in |
| 287 | the given basic block. The field may be left NULL, of course, |
| 288 | if it is not possible or profitable to do the optimization. |
| 289 | |
| 290 | DEF_BSI is an iterator pointing at the statement defining DEF. |
| 291 | If RECIP_DEF is set, a dominator already has a computation that can |
| 292 | be used. */ |
| 293 | |
| 294 | static void |
| 295 | insert_reciprocals (gimple_stmt_iterator *def_gsi, struct occurrence *occ, |
| 296 | tree def, tree recip_def, int threshold) |
| 297 | { |
| 298 | tree type; |
| 299 | gimple new_stmt; |
| 300 | gimple_stmt_iterator gsi; |
| 301 | struct occurrence *occ_child; |
| 302 | |
| 303 | if (!recip_def |
| 304 | && (occ->bb_has_division || !flag_trapping_math) |
| 305 | && occ->num_divisions >= threshold) |
| 306 | { |
| 307 | /* Make a variable with the replacement and substitute it. */ |
| 308 | type = TREE_TYPE (def); |
| 309 | recip_def = make_rename_temp (type, "reciptmp"); |
| 310 | new_stmt = gimple_build_assign_with_ops (RDIV_EXPR, recip_def, |
| 311 | build_one_cst (type), def); |
| 312 | |
| 313 | if (occ->bb_has_division) |
| 314 | { |
| 315 | /* Case 1: insert before an existing division. */ |
| 316 | gsi = gsi_after_labels (occ->bb); |
| 317 | while (!gsi_end_p (gsi) && !is_division_by (gsi_stmt (gsi), def)) |
| 318 | gsi_next (&gsi); |
| 319 | |
| 320 | gsi_insert_before (&gsi, new_stmt, GSI_SAME_STMT); |
| 321 | } |
| 322 | else if (def_gsi && occ->bb == def_gsi->bb) |
| 323 | { |
| 324 | /* Case 2: insert right after the definition. Note that this will |
| 325 | never happen if the definition statement can throw, because in |
| 326 | that case the sole successor of the statement's basic block will |
| 327 | dominate all the uses as well. */ |
| 328 | gsi_insert_after (def_gsi, new_stmt, GSI_NEW_STMT); |
| 329 | } |
| 330 | else |
| 331 | { |
| 332 | /* Case 3: insert in a basic block not containing defs/uses. */ |
| 333 | gsi = gsi_after_labels (occ->bb); |
| 334 | gsi_insert_before (&gsi, new_stmt, GSI_SAME_STMT); |
| 335 | } |
| 336 | |
| 337 | occ->recip_def_stmt = new_stmt; |
| 338 | } |
| 339 | |
| 340 | occ->recip_def = recip_def; |
| 341 | for (occ_child = occ->children; occ_child; occ_child = occ_child->next) |
| 342 | insert_reciprocals (def_gsi, occ_child, def, recip_def, threshold); |
| 343 | } |
| 344 | |
| 345 | |
| 346 | /* Replace the division at USE_P with a multiplication by the reciprocal, if |
| 347 | possible. */ |
| 348 | |
| 349 | static inline void |
| 350 | replace_reciprocal (use_operand_p use_p) |
| 351 | { |
| 352 | gimple use_stmt = USE_STMT (use_p); |
| 353 | basic_block bb = gimple_bb (use_stmt); |
| 354 | struct occurrence *occ = (struct occurrence *) bb->aux; |
| 355 | |
| 356 | if (optimize_bb_for_speed_p (bb) |
| 357 | && occ->recip_def && use_stmt != occ->recip_def_stmt) |
| 358 | { |
| 359 | gimple_assign_set_rhs_code (use_stmt, MULT_EXPR); |
| 360 | SET_USE (use_p, occ->recip_def); |
| 361 | fold_stmt_inplace (use_stmt); |
| 362 | update_stmt (use_stmt); |
| 363 | } |
| 364 | } |
| 365 | |
| 366 | |
| 367 | /* Free OCC and return one more "struct occurrence" to be freed. */ |
| 368 | |
| 369 | static struct occurrence * |
| 370 | free_bb (struct occurrence *occ) |
| 371 | { |
| 372 | struct occurrence *child, *next; |
| 373 | |
| 374 | /* First get the two pointers hanging off OCC. */ |
| 375 | next = occ->next; |
| 376 | child = occ->children; |
| 377 | occ->bb->aux = NULL; |
| 378 | pool_free (occ_pool, occ); |
| 379 | |
| 380 | /* Now ensure that we don't recurse unless it is necessary. */ |
| 381 | if (!child) |
| 382 | return next; |
| 383 | else |
| 384 | { |
| 385 | while (next) |
| 386 | next = free_bb (next); |
| 387 | |
| 388 | return child; |
| 389 | } |
| 390 | } |
| 391 | |
| 392 | |
| 393 | /* Look for floating-point divisions among DEF's uses, and try to |
| 394 | replace them by multiplications with the reciprocal. Add |
| 395 | as many statements computing the reciprocal as needed. |
| 396 | |
| 397 | DEF must be a GIMPLE register of a floating-point type. */ |
| 398 | |
| 399 | static void |
| 400 | execute_cse_reciprocals_1 (gimple_stmt_iterator *def_gsi, tree def) |
| 401 | { |
| 402 | use_operand_p use_p; |
| 403 | imm_use_iterator use_iter; |
| 404 | struct occurrence *occ; |
| 405 | int count = 0, threshold; |
| 406 | |
| 407 | gcc_assert (FLOAT_TYPE_P (TREE_TYPE (def)) && is_gimple_reg (def)); |
| 408 | |
| 409 | FOR_EACH_IMM_USE_FAST (use_p, use_iter, def) |
| 410 | { |
| 411 | gimple use_stmt = USE_STMT (use_p); |
| 412 | if (is_division_by (use_stmt, def)) |
| 413 | { |
| 414 | register_division_in (gimple_bb (use_stmt)); |
| 415 | count++; |
| 416 | } |
| 417 | } |
| 418 | |
| 419 | /* Do the expensive part only if we can hope to optimize something. */ |
| 420 | threshold = targetm.min_divisions_for_recip_mul (TYPE_MODE (TREE_TYPE (def))); |
| 421 | if (count >= threshold) |
| 422 | { |
| 423 | gimple use_stmt; |
| 424 | for (occ = occ_head; occ; occ = occ->next) |
| 425 | { |
| 426 | compute_merit (occ); |
| 427 | insert_reciprocals (def_gsi, occ, def, NULL, threshold); |
| 428 | } |
| 429 | |
| 430 | FOR_EACH_IMM_USE_STMT (use_stmt, use_iter, def) |
| 431 | { |
| 432 | if (is_division_by (use_stmt, def)) |
| 433 | { |
| 434 | FOR_EACH_IMM_USE_ON_STMT (use_p, use_iter) |
| 435 | replace_reciprocal (use_p); |
| 436 | } |
| 437 | } |
| 438 | } |
| 439 | |
| 440 | for (occ = occ_head; occ; ) |
| 441 | occ = free_bb (occ); |
| 442 | |
| 443 | occ_head = NULL; |
| 444 | } |
| 445 | |
| 446 | static bool |
| 447 | gate_cse_reciprocals (void) |
| 448 | { |
| 449 | return optimize && flag_reciprocal_math; |
| 450 | } |
| 451 | |
| 452 | /* Go through all the floating-point SSA_NAMEs, and call |
| 453 | execute_cse_reciprocals_1 on each of them. */ |
| 454 | static unsigned int |
| 455 | execute_cse_reciprocals (void) |
| 456 | { |
| 457 | basic_block bb; |
| 458 | tree arg; |
| 459 | |
| 460 | occ_pool = create_alloc_pool ("dominators for recip", |
| 461 | sizeof (struct occurrence), |
| 462 | n_basic_blocks / 3 + 1); |
| 463 | |
| 464 | calculate_dominance_info (CDI_DOMINATORS); |
| 465 | calculate_dominance_info (CDI_POST_DOMINATORS); |
| 466 | |
| 467 | #ifdef ENABLE_CHECKING |
| 468 | FOR_EACH_BB (bb) |
| 469 | gcc_assert (!bb->aux); |
| 470 | #endif |
| 471 | |
| 472 | for (arg = DECL_ARGUMENTS (cfun->decl); arg; arg = TREE_CHAIN (arg)) |
| 473 | if (gimple_default_def (cfun, arg) |
| 474 | && FLOAT_TYPE_P (TREE_TYPE (arg)) |
| 475 | && is_gimple_reg (arg)) |
| 476 | execute_cse_reciprocals_1 (NULL, gimple_default_def (cfun, arg)); |
| 477 | |
| 478 | FOR_EACH_BB (bb) |
| 479 | { |
| 480 | gimple_stmt_iterator gsi; |
| 481 | gimple phi; |
| 482 | tree def; |
| 483 | |
| 484 | for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
| 485 | { |
| 486 | phi = gsi_stmt (gsi); |
| 487 | def = PHI_RESULT (phi); |
| 488 | if (FLOAT_TYPE_P (TREE_TYPE (def)) |
| 489 | && is_gimple_reg (def)) |
| 490 | execute_cse_reciprocals_1 (NULL, def); |
| 491 | } |
| 492 | |
| 493 | for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
| 494 | { |
| 495 | gimple stmt = gsi_stmt (gsi); |
| 496 | |
| 497 | if (gimple_has_lhs (stmt) |
| 498 | && (def = SINGLE_SSA_TREE_OPERAND (stmt, SSA_OP_DEF)) != NULL |
| 499 | && FLOAT_TYPE_P (TREE_TYPE (def)) |
| 500 | && TREE_CODE (def) == SSA_NAME) |
| 501 | execute_cse_reciprocals_1 (&gsi, def); |
| 502 | } |
| 503 | |
| 504 | if (optimize_bb_for_size_p (bb)) |
| 505 | continue; |
| 506 | |
| 507 | /* Scan for a/func(b) and convert it to reciprocal a*rfunc(b). */ |
| 508 | for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
| 509 | { |
| 510 | gimple stmt = gsi_stmt (gsi); |
| 511 | tree fndecl; |
| 512 | |
| 513 | if (is_gimple_assign (stmt) |
| 514 | && gimple_assign_rhs_code (stmt) == RDIV_EXPR) |
| 515 | { |
| 516 | tree arg1 = gimple_assign_rhs2 (stmt); |
| 517 | gimple stmt1; |
| 518 | |
| 519 | if (TREE_CODE (arg1) != SSA_NAME) |
| 520 | continue; |
| 521 | |
| 522 | stmt1 = SSA_NAME_DEF_STMT (arg1); |
| 523 | |
| 524 | if (is_gimple_call (stmt1) |
| 525 | && gimple_call_lhs (stmt1) |
| 526 | && (fndecl = gimple_call_fndecl (stmt1)) |
| 527 | && (DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL |
| 528 | || DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_MD)) |
| 529 | { |
| 530 | enum built_in_function code; |
| 531 | bool md_code; |
| 532 | |
| 533 | code = DECL_FUNCTION_CODE (fndecl); |
| 534 | md_code = DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_MD; |
| 535 | |
| 536 | fndecl = targetm.builtin_reciprocal (code, md_code, false); |
| 537 | if (!fndecl) |
| 538 | continue; |
| 539 | |
| 540 | gimple_call_set_fndecl (stmt1, fndecl); |
| 541 | update_stmt (stmt1); |
| 542 | |
| 543 | gimple_assign_set_rhs_code (stmt, MULT_EXPR); |
| 544 | fold_stmt_inplace (stmt); |
| 545 | update_stmt (stmt); |
| 546 | } |
| 547 | } |
| 548 | } |
| 549 | } |
| 550 | |
| 551 | free_dominance_info (CDI_DOMINATORS); |
| 552 | free_dominance_info (CDI_POST_DOMINATORS); |
| 553 | free_alloc_pool (occ_pool); |
| 554 | return 0; |
| 555 | } |
| 556 | |
| 557 | struct gimple_opt_pass pass_cse_reciprocals = |
| 558 | { |
| 559 | { |
| 560 | GIMPLE_PASS, |
| 561 | "recip", /* name */ |
| 562 | gate_cse_reciprocals, /* gate */ |
| 563 | execute_cse_reciprocals, /* execute */ |
| 564 | NULL, /* sub */ |
| 565 | NULL, /* next */ |
| 566 | 0, /* static_pass_number */ |
| 567 | 0, /* tv_id */ |
| 568 | PROP_ssa, /* properties_required */ |
| 569 | 0, /* properties_provided */ |
| 570 | 0, /* properties_destroyed */ |
| 571 | 0, /* todo_flags_start */ |
| 572 | TODO_dump_func | TODO_update_ssa | TODO_verify_ssa |
| 573 | | TODO_verify_stmts /* todo_flags_finish */ |
| 574 | } |
| 575 | }; |
| 576 | |
| 577 | /* Records an occurrence at statement USE_STMT in the vector of trees |
| 578 | STMTS if it is dominated by *TOP_BB or dominates it or this basic block |
| 579 | is not yet initialized. Returns true if the occurrence was pushed on |
| 580 | the vector. Adjusts *TOP_BB to be the basic block dominating all |
| 581 | statements in the vector. */ |
| 582 | |
| 583 | static bool |
| 584 | maybe_record_sincos (VEC(gimple, heap) **stmts, |
| 585 | basic_block *top_bb, gimple use_stmt) |
| 586 | { |
| 587 | basic_block use_bb = gimple_bb (use_stmt); |
| 588 | if (*top_bb |
| 589 | && (*top_bb == use_bb |
| 590 | || dominated_by_p (CDI_DOMINATORS, use_bb, *top_bb))) |
| 591 | VEC_safe_push (gimple, heap, *stmts, use_stmt); |
| 592 | else if (!*top_bb |
| 593 | || dominated_by_p (CDI_DOMINATORS, *top_bb, use_bb)) |
| 594 | { |
| 595 | VEC_safe_push (gimple, heap, *stmts, use_stmt); |
| 596 | *top_bb = use_bb; |
| 597 | } |
| 598 | else |
| 599 | return false; |
| 600 | |
| 601 | return true; |
| 602 | } |
| 603 | |
| 604 | /* Look for sin, cos and cexpi calls with the same argument NAME and |
| 605 | create a single call to cexpi CSEing the result in this case. |
| 606 | We first walk over all immediate uses of the argument collecting |
| 607 | statements that we can CSE in a vector and in a second pass replace |
| 608 | the statement rhs with a REALPART or IMAGPART expression on the |
| 609 | result of the cexpi call we insert before the use statement that |
| 610 | dominates all other candidates. */ |
| 611 | |
| 612 | static void |
| 613 | execute_cse_sincos_1 (tree name) |
| 614 | { |
| 615 | gimple_stmt_iterator gsi; |
| 616 | imm_use_iterator use_iter; |
| 617 | tree fndecl, res, type; |
| 618 | gimple def_stmt, use_stmt, stmt; |
| 619 | int seen_cos = 0, seen_sin = 0, seen_cexpi = 0; |
| 620 | VEC(gimple, heap) *stmts = NULL; |
| 621 | basic_block top_bb = NULL; |
| 622 | int i; |
| 623 | |
| 624 | type = TREE_TYPE (name); |
| 625 | FOR_EACH_IMM_USE_STMT (use_stmt, use_iter, name) |
| 626 | { |
| 627 | if (gimple_code (use_stmt) != GIMPLE_CALL |
| 628 | || !gimple_call_lhs (use_stmt) |
| 629 | || !(fndecl = gimple_call_fndecl (use_stmt)) |
| 630 | || DECL_BUILT_IN_CLASS (fndecl) != BUILT_IN_NORMAL) |
| 631 | continue; |
| 632 | |
| 633 | switch (DECL_FUNCTION_CODE (fndecl)) |
| 634 | { |
| 635 | CASE_FLT_FN (BUILT_IN_COS): |
| 636 | seen_cos |= maybe_record_sincos (&stmts, &top_bb, use_stmt) ? 1 : 0; |
| 637 | break; |
| 638 | |
| 639 | CASE_FLT_FN (BUILT_IN_SIN): |
| 640 | seen_sin |= maybe_record_sincos (&stmts, &top_bb, use_stmt) ? 1 : 0; |
| 641 | break; |
| 642 | |
| 643 | CASE_FLT_FN (BUILT_IN_CEXPI): |
| 644 | seen_cexpi |= maybe_record_sincos (&stmts, &top_bb, use_stmt) ? 1 : 0; |
| 645 | break; |
| 646 | |
| 647 | default:; |
| 648 | } |
| 649 | } |
| 650 | |
| 651 | if (seen_cos + seen_sin + seen_cexpi <= 1) |
| 652 | { |
| 653 | VEC_free(gimple, heap, stmts); |
| 654 | return; |
| 655 | } |
| 656 | |
| 657 | /* Simply insert cexpi at the beginning of top_bb but not earlier than |
| 658 | the name def statement. */ |
| 659 | fndecl = mathfn_built_in (type, BUILT_IN_CEXPI); |
| 660 | if (!fndecl) |
| 661 | return; |
| 662 | res = make_rename_temp (TREE_TYPE (TREE_TYPE (fndecl)), "sincostmp"); |
| 663 | stmt = gimple_build_call (fndecl, 1, name); |
| 664 | gimple_call_set_lhs (stmt, res); |
| 665 | |
| 666 | def_stmt = SSA_NAME_DEF_STMT (name); |
| 667 | if (!SSA_NAME_IS_DEFAULT_DEF (name) |
| 668 | && gimple_code (def_stmt) != GIMPLE_PHI |
| 669 | && gimple_bb (def_stmt) == top_bb) |
| 670 | { |
| 671 | gsi = gsi_for_stmt (def_stmt); |
| 672 | gsi_insert_after (&gsi, stmt, GSI_SAME_STMT); |
| 673 | } |
| 674 | else |
| 675 | { |
| 676 | gsi = gsi_after_labels (top_bb); |
| 677 | gsi_insert_before (&gsi, stmt, GSI_SAME_STMT); |
| 678 | } |
| 679 | update_stmt (stmt); |
| 680 | |
| 681 | /* And adjust the recorded old call sites. */ |
| 682 | for (i = 0; VEC_iterate(gimple, stmts, i, use_stmt); ++i) |
| 683 | { |
| 684 | tree rhs = NULL; |
| 685 | fndecl = gimple_call_fndecl (use_stmt); |
| 686 | |
| 687 | switch (DECL_FUNCTION_CODE (fndecl)) |
| 688 | { |
| 689 | CASE_FLT_FN (BUILT_IN_COS): |
| 690 | rhs = fold_build1 (REALPART_EXPR, type, res); |
| 691 | break; |
| 692 | |
| 693 | CASE_FLT_FN (BUILT_IN_SIN): |
| 694 | rhs = fold_build1 (IMAGPART_EXPR, type, res); |
| 695 | break; |
| 696 | |
| 697 | CASE_FLT_FN (BUILT_IN_CEXPI): |
| 698 | rhs = res; |
| 699 | break; |
| 700 | |
| 701 | default:; |
| 702 | gcc_unreachable (); |
| 703 | } |
| 704 | |
| 705 | /* Replace call with a copy. */ |
| 706 | stmt = gimple_build_assign (gimple_call_lhs (use_stmt), rhs); |
| 707 | |
| 708 | gsi = gsi_for_stmt (use_stmt); |
| 709 | gsi_insert_after (&gsi, stmt, GSI_SAME_STMT); |
| 710 | gsi_remove (&gsi, true); |
| 711 | } |
| 712 | |
| 713 | VEC_free(gimple, heap, stmts); |
| 714 | } |
| 715 | |
| 716 | /* Go through all calls to sin, cos and cexpi and call execute_cse_sincos_1 |
| 717 | on the SSA_NAME argument of each of them. */ |
| 718 | |
| 719 | static unsigned int |
| 720 | execute_cse_sincos (void) |
| 721 | { |
| 722 | basic_block bb; |
| 723 | |
| 724 | calculate_dominance_info (CDI_DOMINATORS); |
| 725 | |
| 726 | FOR_EACH_BB (bb) |
| 727 | { |
| 728 | gimple_stmt_iterator gsi; |
| 729 | |
| 730 | for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
| 731 | { |
| 732 | gimple stmt = gsi_stmt (gsi); |
| 733 | tree fndecl; |
| 734 | |
| 735 | if (is_gimple_call (stmt) |
| 736 | && gimple_call_lhs (stmt) |
| 737 | && (fndecl = gimple_call_fndecl (stmt)) |
| 738 | && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL) |
| 739 | { |
| 740 | tree arg; |
| 741 | |
| 742 | switch (DECL_FUNCTION_CODE (fndecl)) |
| 743 | { |
| 744 | CASE_FLT_FN (BUILT_IN_COS): |
| 745 | CASE_FLT_FN (BUILT_IN_SIN): |
| 746 | CASE_FLT_FN (BUILT_IN_CEXPI): |
| 747 | arg = gimple_call_arg (stmt, 0); |
| 748 | if (TREE_CODE (arg) == SSA_NAME) |
| 749 | execute_cse_sincos_1 (arg); |
| 750 | break; |
| 751 | |
| 752 | default:; |
| 753 | } |
| 754 | } |
| 755 | } |
| 756 | } |
| 757 | |
| 758 | free_dominance_info (CDI_DOMINATORS); |
| 759 | return 0; |
| 760 | } |
| 761 | |
| 762 | static bool |
| 763 | gate_cse_sincos (void) |
| 764 | { |
| 765 | /* Make sure we have either sincos or cexp. */ |
| 766 | return (TARGET_HAS_SINCOS |
| 767 | || TARGET_C99_FUNCTIONS) |
| 768 | && optimize; |
| 769 | } |
| 770 | |
| 771 | struct gimple_opt_pass pass_cse_sincos = |
| 772 | { |
| 773 | { |
| 774 | GIMPLE_PASS, |
| 775 | "sincos", /* name */ |
| 776 | gate_cse_sincos, /* gate */ |
| 777 | execute_cse_sincos, /* execute */ |
| 778 | NULL, /* sub */ |
| 779 | NULL, /* next */ |
| 780 | 0, /* static_pass_number */ |
| 781 | 0, /* tv_id */ |
| 782 | PROP_ssa, /* properties_required */ |
| 783 | 0, /* properties_provided */ |
| 784 | 0, /* properties_destroyed */ |
| 785 | 0, /* todo_flags_start */ |
| 786 | TODO_dump_func | TODO_update_ssa | TODO_verify_ssa |
| 787 | | TODO_verify_stmts /* todo_flags_finish */ |
| 788 | } |
| 789 | }; |
| 790 | |
| 791 | /* Find all expressions in the form of sqrt(a/b) and |
| 792 | convert them to rsqrt(b/a). */ |
| 793 | |
| 794 | static unsigned int |
| 795 | execute_convert_to_rsqrt (void) |
| 796 | { |
| 797 | basic_block bb; |
| 798 | |
| 799 | FOR_EACH_BB (bb) |
| 800 | { |
| 801 | gimple_stmt_iterator gsi; |
| 802 | |
| 803 | for (gsi = gsi_after_labels (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
| 804 | { |
| 805 | gimple stmt = gsi_stmt (gsi); |
| 806 | tree fndecl; |
| 807 | |
| 808 | if (is_gimple_call (stmt) |
| 809 | && gimple_call_lhs (stmt) |
| 810 | && (fndecl = gimple_call_fndecl (stmt)) |
| 811 | && (DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL |
| 812 | || DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_MD)) |
| 813 | { |
| 814 | enum built_in_function code; |
| 815 | bool md_code; |
| 816 | tree arg1; |
| 817 | gimple stmt1; |
| 818 | |
| 819 | code = DECL_FUNCTION_CODE (fndecl); |
| 820 | md_code = DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_MD; |
| 821 | |
| 822 | fndecl = targetm.builtin_reciprocal (code, md_code, true); |
| 823 | if (!fndecl) |
| 824 | continue; |
| 825 | |
| 826 | arg1 = gimple_call_arg (stmt, 0); |
| 827 | |
| 828 | if (TREE_CODE (arg1) != SSA_NAME) |
| 829 | continue; |
| 830 | |
| 831 | stmt1 = SSA_NAME_DEF_STMT (arg1); |
| 832 | |
| 833 | if (is_gimple_assign (stmt1) |
| 834 | && gimple_assign_rhs_code (stmt1) == RDIV_EXPR) |
| 835 | { |
| 836 | tree arg10, arg11; |
| 837 | |
| 838 | arg10 = gimple_assign_rhs1 (stmt1); |
| 839 | arg11 = gimple_assign_rhs2 (stmt1); |
| 840 | |
| 841 | /* Swap operands of RDIV_EXPR. */ |
| 842 | gimple_assign_set_rhs1 (stmt1, arg11); |
| 843 | gimple_assign_set_rhs2 (stmt1, arg10); |
| 844 | fold_stmt_inplace (stmt1); |
| 845 | update_stmt (stmt1); |
| 846 | |
| 847 | gimple_call_set_fndecl (stmt, fndecl); |
| 848 | update_stmt (stmt); |
| 849 | } |
| 850 | } |
| 851 | } |
| 852 | } |
| 853 | |
| 854 | return 0; |
| 855 | } |
| 856 | |
| 857 | static bool |
| 858 | gate_convert_to_rsqrt (void) |
| 859 | { |
| 860 | return flag_unsafe_math_optimizations && optimize; |
| 861 | } |
| 862 | |
| 863 | struct gimple_opt_pass pass_convert_to_rsqrt = |
| 864 | { |
| 865 | { |
| 866 | GIMPLE_PASS, |
| 867 | "rsqrt", /* name */ |
| 868 | gate_convert_to_rsqrt, /* gate */ |
| 869 | execute_convert_to_rsqrt, /* execute */ |
| 870 | NULL, /* sub */ |
| 871 | NULL, /* next */ |
| 872 | 0, /* static_pass_number */ |
| 873 | 0, /* tv_id */ |
| 874 | PROP_ssa, /* properties_required */ |
| 875 | 0, /* properties_provided */ |
| 876 | 0, /* properties_destroyed */ |
| 877 | 0, /* todo_flags_start */ |
| 878 | TODO_dump_func | TODO_update_ssa | TODO_verify_ssa |
| 879 | | TODO_verify_stmts /* todo_flags_finish */ |
| 880 | } |
| 881 | }; |