| File: | build/gcc/tree-ssa-loop-unswitch.cc |
| Warning: | line 1091, column 7 Value stored to 'changed' is never read |
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| 1 | /* Loop unswitching. |
| 2 | Copyright (C) 2004-2023 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 | #include "config.h" |
| 21 | #include "system.h" |
| 22 | #include "coretypes.h" |
| 23 | #include "backend.h" |
| 24 | #include "tree.h" |
| 25 | #include "gimple.h" |
| 26 | #include "tree-pass.h" |
| 27 | #include "ssa.h" |
| 28 | #include "fold-const.h" |
| 29 | #include "gimplify.h" |
| 30 | #include "tree-cfg.h" |
| 31 | #include "tree-ssa.h" |
| 32 | #include "tree-ssa-loop-niter.h" |
| 33 | #include "tree-ssa-loop.h" |
| 34 | #include "tree-into-ssa.h" |
| 35 | #include "cfgloop.h" |
| 36 | #include "tree-inline.h" |
| 37 | #include "gimple-iterator.h" |
| 38 | #include "cfghooks.h" |
| 39 | #include "tree-ssa-loop-manip.h" |
| 40 | #include "tree-vectorizer.h" |
| 41 | #include "tree-pretty-print.h" |
| 42 | #include "gimple-range.h" |
| 43 | #include "dbgcnt.h" |
| 44 | #include "cfganal.h" |
| 45 | |
| 46 | /* This file implements the loop unswitching, i.e. transformation of loops like |
| 47 | |
| 48 | while (A) |
| 49 | { |
| 50 | if (inv) |
| 51 | B; |
| 52 | |
| 53 | X; |
| 54 | |
| 55 | if (!inv) |
| 56 | C; |
| 57 | } |
| 58 | |
| 59 | where inv is the loop invariant, into |
| 60 | |
| 61 | if (inv) |
| 62 | { |
| 63 | while (A) |
| 64 | { |
| 65 | B; |
| 66 | X; |
| 67 | } |
| 68 | } |
| 69 | else |
| 70 | { |
| 71 | while (A) |
| 72 | { |
| 73 | X; |
| 74 | C; |
| 75 | } |
| 76 | } |
| 77 | |
| 78 | Inv is considered invariant iff the values it compares are both invariant; |
| 79 | tree-ssa-loop-im.cc ensures that all the suitable conditions are in this |
| 80 | shape. */ |
| 81 | |
| 82 | /* Loop unswitching algorithm for innermost loops works in the following steps: |
| 83 | |
| 84 | 1) Number of instructions is estimated for each BB that belongs to a loop. |
| 85 | 2) Unswitching candidates are found for gcond and gswitch statements |
| 86 | (note that an unswitching predicate for a gswitch actually corresponds |
| 87 | to a non-default edge so it can contain multiple cases). |
| 88 | 3) The so called unswitch predicates are stored in a cache where the |
| 89 | gimple_uid of the last stmt in a basic-block is an index to the cache. |
| 90 | 4) We consider one by one the unswitching candidates and calculate BBs that |
| 91 | will be reachable in the unswitch version. |
| 92 | 5) A selected predicate is chosen and we simplify the CFG (dead edges) in |
| 93 | both versions of the loop. We utilize both Ranger for condition |
| 94 | simplification and also symbol equivalence. The folded if conditions |
| 95 | are replaced with true/false values, while for gswitch we mark the |
| 96 | corresponding edges with a pass-defined unreachable flag. |
| 97 | 6) Every time we unswitch a loop, we save unswitch_predicate to a vector |
| 98 | together with information if true or false edge was taken. Doing that |
| 99 | we have a so called PREDICATE_PATH that is utilized for simplification |
| 100 | of the cloned loop. |
| 101 | 7) The process is repeated until we reach a growth threshold or all |
| 102 | unswitching opportunities are taken. */ |
| 103 | |
| 104 | /* A tuple that holds a GENERIC condition and value range for an unswitching |
| 105 | predicate. */ |
| 106 | |
| 107 | struct unswitch_predicate |
| 108 | { |
| 109 | /* CTOR for a switch edge predicate. */ |
| 110 | unswitch_predicate (tree cond, tree lhs_, int edge_index_, edge e, |
| 111 | const int_range_max& edge_range) |
| 112 | : condition (cond), lhs (lhs_), |
| 113 | true_range (edge_range), edge_index (edge_index_), switch_p (true) |
| 114 | { |
| 115 | gcc_assert (!(e->flags & (EDGE_TRUE_VALUE|EDGE_FALSE_VALUE))((void)(!(!(e->flags & (EDGE_TRUE_VALUE|EDGE_FALSE_VALUE )) && irange::supports_p (((contains_struct_check ((lhs ), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 116, __FUNCTION__))->typed.type))) ? fancy_abort ("/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 116, __FUNCTION__), 0 : 0)) |
| 116 | && irange::supports_p (TREE_TYPE (lhs)))((void)(!(!(e->flags & (EDGE_TRUE_VALUE|EDGE_FALSE_VALUE )) && irange::supports_p (((contains_struct_check ((lhs ), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 116, __FUNCTION__))->typed.type))) ? fancy_abort ("/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 116, __FUNCTION__), 0 : 0)); |
| 117 | false_range = true_range; |
| 118 | if (!false_range.varying_p () |
| 119 | && !false_range.undefined_p ()) |
| 120 | false_range.invert (); |
| 121 | count = e->count (); |
| 122 | num = predicates->length (); |
| 123 | predicates->safe_push (this); |
| 124 | } |
| 125 | |
| 126 | /* CTOR for a GIMPLE condition statement. */ |
| 127 | unswitch_predicate (gcond *stmt) |
| 128 | : switch_p (false) |
| 129 | { |
| 130 | basic_block bb = gimple_bb (stmt); |
| 131 | if (EDGE_SUCC (bb, 0)(*(bb)->succs)[(0)]->flags & EDGE_TRUE_VALUE) |
| 132 | edge_index = 0; |
| 133 | else |
| 134 | edge_index = 1; |
| 135 | lhs = gimple_cond_lhs (stmt); |
| 136 | tree rhs = gimple_cond_rhs (stmt); |
| 137 | enum tree_code code = gimple_cond_code (stmt); |
| 138 | condition = build2 (code, boolean_type_nodeglobal_trees[TI_BOOLEAN_TYPE], lhs, rhs); |
| 139 | count = EDGE_SUCC (bb, 0)(*(bb)->succs)[(0)]->count ().max (EDGE_SUCC (bb, 1)(*(bb)->succs)[(1)]->count ()); |
| 140 | if (irange::supports_p (TREE_TYPE (lhs)((contains_struct_check ((lhs), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 140, __FUNCTION__))->typed.type))) |
| 141 | { |
| 142 | auto range_op = range_op_handler (code, TREE_TYPE (lhs)((contains_struct_check ((lhs), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 142, __FUNCTION__))->typed.type)); |
| 143 | int_range<2> rhs_range (TREE_TYPE (rhs)((contains_struct_check ((rhs), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 143, __FUNCTION__))->typed.type)); |
| 144 | if (CONSTANT_CLASS_P (rhs)(tree_code_type_tmpl <0>::tree_code_type[(int) (((enum tree_code ) (rhs)->base.code))] == tcc_constant)) |
| 145 | rhs_range.set (rhs, rhs); |
| 146 | if (!range_op.op1_range (true_range, TREE_TYPE (lhs)((contains_struct_check ((lhs), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 146, __FUNCTION__))->typed.type), |
| 147 | int_range<2> (boolean_true_nodeglobal_trees[TI_BOOLEAN_TRUE], |
| 148 | boolean_true_nodeglobal_trees[TI_BOOLEAN_TRUE]), rhs_range) |
| 149 | || !range_op.op1_range (false_range, TREE_TYPE (lhs)((contains_struct_check ((lhs), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 149, __FUNCTION__))->typed.type), |
| 150 | int_range<2> (boolean_false_nodeglobal_trees[TI_BOOLEAN_FALSE], |
| 151 | boolean_false_nodeglobal_trees[TI_BOOLEAN_FALSE]), |
| 152 | rhs_range)) |
| 153 | { |
| 154 | true_range.set_varying (TREE_TYPE (lhs)((contains_struct_check ((lhs), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 154, __FUNCTION__))->typed.type)); |
| 155 | false_range.set_varying (TREE_TYPE (lhs)((contains_struct_check ((lhs), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 155, __FUNCTION__))->typed.type)); |
| 156 | } |
| 157 | } |
| 158 | num = predicates->length (); |
| 159 | predicates->safe_push (this); |
| 160 | } |
| 161 | |
| 162 | /* Copy ranges for purpose of usage in predicate path. */ |
| 163 | |
| 164 | inline void |
| 165 | copy_merged_ranges () |
| 166 | { |
| 167 | merged_true_range = true_range; |
| 168 | merged_false_range = false_range; |
| 169 | } |
| 170 | |
| 171 | /* GENERIC unswitching expression testing LHS against CONSTANT. */ |
| 172 | tree condition; |
| 173 | |
| 174 | /* LHS of the expression. */ |
| 175 | tree lhs; |
| 176 | |
| 177 | /* Initial ranges (when the expression is true/false) for the expression. */ |
| 178 | int_range_max true_range = {}, false_range = {}; |
| 179 | |
| 180 | /* Modified range that is part of a predicate path. */ |
| 181 | int_range_max merged_true_range = {}, merged_false_range = {}; |
| 182 | |
| 183 | /* Index of the edge the predicate belongs to in the successor vector. */ |
| 184 | int edge_index; |
| 185 | |
| 186 | /* The profile count of this predicate. */ |
| 187 | profile_count count; |
| 188 | |
| 189 | /* Whether the predicate was created from a switch statement. */ |
| 190 | bool switch_p; |
| 191 | |
| 192 | /* The number of the predicate in the predicates vector below. */ |
| 193 | unsigned num; |
| 194 | |
| 195 | /* Vector of all used predicates, used for assigning a unique id that |
| 196 | can be used for bitmap operations. */ |
| 197 | static vec<unswitch_predicate *> *predicates; |
| 198 | }; |
| 199 | |
| 200 | vec<unswitch_predicate *> *unswitch_predicate::predicates; |
| 201 | |
| 202 | /* Ranger instance used in the pass. */ |
| 203 | static gimple_ranger *ranger = NULLnullptr; |
| 204 | |
| 205 | /* Cache storage for unswitch_predicate belonging to a basic block. */ |
| 206 | static vec<vec<unswitch_predicate *>> *bb_predicates; |
| 207 | |
| 208 | /* The type represents a predicate path leading to a basic block. */ |
| 209 | typedef vec<std::pair<unswitch_predicate *, bool>> predicate_vector; |
| 210 | |
| 211 | static class loop *tree_unswitch_loop (class loop *, edge, tree); |
| 212 | static bool tree_unswitch_single_loop (class loop *, dump_user_location_t, |
| 213 | predicate_vector &predicate_path, |
| 214 | unsigned loop_size, unsigned &budget, |
| 215 | int ignored_edge_flag, bitmap, |
| 216 | unswitch_predicate * = NULLnullptr, |
| 217 | basic_block = NULLnullptr); |
| 218 | static void |
| 219 | find_unswitching_predicates_for_bb (basic_block bb, class loop *loop, |
| 220 | class loop *&outer_loop, |
| 221 | vec<unswitch_predicate *> &candidates, |
| 222 | unswitch_predicate *&hottest, |
| 223 | basic_block &hottest_bb); |
| 224 | static bool tree_unswitch_outer_loop (class loop *); |
| 225 | static edge find_loop_guard (class loop *, vec<gimple *>&); |
| 226 | static bool empty_bb_without_guard_p (class loop *, basic_block, |
| 227 | vec<gimple *>&); |
| 228 | static bool used_outside_loop_p (class loop *, tree, vec<gimple *>&); |
| 229 | static void hoist_guard (class loop *, edge); |
| 230 | static bool check_exit_phi (class loop *); |
| 231 | static tree get_vop_from_header (class loop *); |
| 232 | static void clean_up_after_unswitching (int); |
| 233 | |
| 234 | /* Return vector of predicates that belong to a basic block. */ |
| 235 | |
| 236 | static vec<unswitch_predicate *> & |
| 237 | get_predicates_for_bb (basic_block bb) |
| 238 | { |
| 239 | gimple *last = last_stmt (bb); |
| 240 | return (*bb_predicates)[last == NULLnullptr ? 0 : gimple_uid (last)]; |
| 241 | } |
| 242 | |
| 243 | /* Save predicates that belong to a basic block. */ |
| 244 | |
| 245 | static void |
| 246 | set_predicates_for_bb (basic_block bb, vec<unswitch_predicate *> predicates) |
| 247 | { |
| 248 | gimple_set_uid (last_stmt (bb), bb_predicates->length ()); |
| 249 | bb_predicates->safe_push (predicates); |
| 250 | } |
| 251 | |
| 252 | /* Initialize LOOP information reused during the unswitching pass. |
| 253 | Return total number of instructions in the loop. Adjusts LOOP to |
| 254 | the outermost loop all candidates are invariant in. */ |
| 255 | |
| 256 | static unsigned |
| 257 | init_loop_unswitch_info (class loop *&loop, unswitch_predicate *&hottest, |
| 258 | basic_block &hottest_bb) |
| 259 | { |
| 260 | unsigned total_insns = 0; |
| 261 | |
| 262 | basic_block *bbs = get_loop_body (loop); |
| 263 | |
| 264 | /* Unswitch only nests with no sibling loops. */ |
| 265 | class loop *outer_loop = loop; |
| 266 | unsigned max_depth = param_max_unswitch_depthglobal_options.x_param_max_unswitch_depth; |
| 267 | while (loop_outer (outer_loop)->num != 0 |
| 268 | && !loop_outer (outer_loop)->inner->next |
| 269 | && --max_depth != 0) |
| 270 | outer_loop = loop_outer (outer_loop); |
| 271 | hottest = NULLnullptr; |
| 272 | hottest_bb = NULLnullptr; |
| 273 | /* Find all unswitching candidates in the innermost loop. */ |
| 274 | for (unsigned i = 0; i != loop->num_nodes; i++) |
| 275 | { |
| 276 | /* Find a bb to unswitch on. */ |
| 277 | vec<unswitch_predicate *> candidates; |
| 278 | candidates.create (1); |
| 279 | find_unswitching_predicates_for_bb (bbs[i], loop, outer_loop, candidates, |
| 280 | hottest, hottest_bb); |
| 281 | if (!candidates.is_empty ()) |
| 282 | set_predicates_for_bb (bbs[i], candidates); |
| 283 | else |
| 284 | { |
| 285 | candidates.release (); |
| 286 | gimple *last = last_stmt (bbs[i]); |
| 287 | if (last != NULLnullptr) |
| 288 | gimple_set_uid (last, 0); |
| 289 | } |
| 290 | } |
| 291 | |
| 292 | if (outer_loop != loop) |
| 293 | { |
| 294 | free (bbs); |
| 295 | bbs = get_loop_body (outer_loop); |
| 296 | } |
| 297 | |
| 298 | /* Calculate instruction count. */ |
| 299 | for (unsigned i = 0; i < outer_loop->num_nodes; i++) |
| 300 | { |
| 301 | unsigned insns = 0; |
| 302 | for (gimple_stmt_iterator gsi = gsi_start_bb (bbs[i]); !gsi_end_p (gsi); |
| 303 | gsi_next (&gsi)) |
| 304 | insns += estimate_num_insns (gsi_stmt (gsi), &eni_size_weights); |
| 305 | /* No predicates to unswitch on in the outer loops. */ |
| 306 | if (!flow_bb_inside_loop_p (loop, bbs[i])) |
| 307 | { |
| 308 | gimple *last = last_stmt (bbs[i]); |
| 309 | if (last != NULLnullptr) |
| 310 | gimple_set_uid (last, 0); |
| 311 | } |
| 312 | |
| 313 | bbs[i]->aux = (void *)(uintptr_t)insns; |
| 314 | total_insns += insns; |
| 315 | } |
| 316 | |
| 317 | free (bbs); |
| 318 | |
| 319 | loop = outer_loop; |
| 320 | return total_insns; |
| 321 | } |
| 322 | |
| 323 | /* Main entry point. Perform loop unswitching on all suitable loops. */ |
| 324 | |
| 325 | unsigned int |
| 326 | tree_ssa_unswitch_loops (function *fun) |
| 327 | { |
| 328 | bool changed_unswitch = false; |
| 329 | bool changed_hoist = false; |
| 330 | auto_edge_flag ignored_edge_flag (fun); |
| 331 | |
| 332 | ranger = enable_ranger (fun); |
| 333 | |
| 334 | /* Go through all loops starting from innermost, hoisting guards. */ |
| 335 | for (auto loop : loops_list (fun, LI_FROM_INNERMOST)) |
| 336 | { |
| 337 | if (loop->inner) |
| 338 | changed_hoist |= tree_unswitch_outer_loop (loop); |
| 339 | } |
| 340 | |
| 341 | /* Go through innermost loops, unswitching on invariant predicates |
| 342 | within those. */ |
| 343 | for (auto loop : loops_list (fun, LI_ONLY_INNERMOST)) |
| 344 | { |
| 345 | /* Perform initial tests if unswitch is eligible. */ |
| 346 | dump_user_location_t loc = find_loop_location (loop); |
| 347 | |
| 348 | /* Do not unswitch in cold regions. */ |
| 349 | if (optimize_loop_for_size_p (loop)) |
| 350 | { |
| 351 | if (dump_enabled_p ()) |
| 352 | dump_printf_loc (MSG_NOTE, loc, |
| 353 | "Not unswitching cold loops\n"); |
| 354 | continue; |
| 355 | } |
| 356 | |
| 357 | /* If the loop is not expected to iterate, there is no need |
| 358 | for unswitching. */ |
| 359 | HOST_WIDE_INTlong iterations = estimated_loop_iterations_int (loop); |
| 360 | if (iterations < 0) |
| 361 | iterations = likely_max_loop_iterations_int (loop); |
| 362 | if (iterations >= 0 && iterations <= 1) |
| 363 | { |
| 364 | if (dump_enabled_p ()) |
| 365 | dump_printf_loc (MSG_NOTE, loc, |
| 366 | "Not unswitching, loop is not expected" |
| 367 | " to iterate\n"); |
| 368 | continue; |
| 369 | } |
| 370 | |
| 371 | bb_predicates = new vec<vec<unswitch_predicate *>> (); |
| 372 | bb_predicates->safe_push (vec<unswitch_predicate *> ()); |
| 373 | unswitch_predicate::predicates = new vec<unswitch_predicate *> (); |
| 374 | |
| 375 | /* Unswitch loop. */ |
| 376 | unswitch_predicate *hottest; |
| 377 | basic_block hottest_bb; |
| 378 | unsigned int loop_size = init_loop_unswitch_info (loop, hottest, |
| 379 | hottest_bb); |
| 380 | unsigned int budget = loop_size + param_max_unswitch_insnsglobal_options.x_param_max_unswitch_insns; |
| 381 | |
| 382 | predicate_vector predicate_path; |
| 383 | predicate_path.create (8); |
| 384 | auto_bitmap handled; |
| 385 | changed_unswitch |= tree_unswitch_single_loop (loop, loc, predicate_path, |
| 386 | loop_size, budget, |
| 387 | ignored_edge_flag, handled, |
| 388 | hottest, hottest_bb); |
| 389 | predicate_path.release (); |
| 390 | |
| 391 | for (auto predlist : bb_predicates) |
| 392 | predlist.release (); |
| 393 | bb_predicates->release (); |
| 394 | delete bb_predicates; |
| 395 | bb_predicates = NULLnullptr; |
| 396 | |
| 397 | for (auto pred : unswitch_predicate::predicates) |
| 398 | delete pred; |
| 399 | unswitch_predicate::predicates->release (); |
| 400 | delete unswitch_predicate::predicates; |
| 401 | unswitch_predicate::predicates = NULLnullptr; |
| 402 | } |
| 403 | |
| 404 | disable_ranger (fun); |
| 405 | clear_aux_for_blocks (); |
| 406 | |
| 407 | if (changed_unswitch) |
| 408 | clean_up_after_unswitching (ignored_edge_flag); |
| 409 | |
| 410 | if (changed_unswitch || changed_hoist) |
| 411 | return TODO_cleanup_cfg(1 << 5); |
| 412 | |
| 413 | return 0; |
| 414 | } |
| 415 | |
| 416 | /* Return TRUE if an SSA_NAME maybe undefined and is therefore |
| 417 | unsuitable for unswitching. STMT is the statement we are |
| 418 | considering for unswitching and LOOP is the loop it appears in. */ |
| 419 | |
| 420 | static bool |
| 421 | is_maybe_undefined (const tree name, gimple *stmt, class loop *loop) |
| 422 | { |
| 423 | /* The loop header is the only block we can trivially determine that |
| 424 | will always be executed. If the comparison is in the loop |
| 425 | header, we know it's OK to unswitch on it. */ |
| 426 | if (gimple_bb (stmt) == loop->header) |
| 427 | return false; |
| 428 | |
| 429 | auto_bitmap visited_ssa; |
| 430 | auto_vec<tree> worklist; |
| 431 | worklist.safe_push (name); |
| 432 | bitmap_set_bit (visited_ssa, SSA_NAME_VERSION (name)(tree_check ((name), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 432, __FUNCTION__, (SSA_NAME)))->base.u.version); |
| 433 | while (!worklist.is_empty ()) |
| 434 | { |
| 435 | tree t = worklist.pop (); |
| 436 | |
| 437 | /* If it's obviously undefined, avoid further computations. */ |
| 438 | if (ssa_undefined_value_p (t, true)) |
| 439 | return true; |
| 440 | |
| 441 | if (ssa_defined_default_def_p (t)) |
| 442 | continue; |
| 443 | |
| 444 | gimple *def = SSA_NAME_DEF_STMT (t)(tree_check ((t), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 444, __FUNCTION__, (SSA_NAME)))->ssa_name.def_stmt; |
| 445 | |
| 446 | /* Check that all the PHI args are fully defined. */ |
| 447 | if (gphi *phi = dyn_cast <gphi *> (def)) |
| 448 | { |
| 449 | for (unsigned i = 0; i < gimple_phi_num_args (phi); ++i) |
| 450 | { |
| 451 | tree t = gimple_phi_arg_def (phi, i); |
| 452 | /* If an SSA has already been seen, it may be a loop, |
| 453 | but we can continue and ignore this use. Otherwise, |
| 454 | add the SSA_NAME to the queue and visit it later. */ |
| 455 | if (TREE_CODE (t)((enum tree_code) (t)->base.code) == SSA_NAME |
| 456 | && bitmap_set_bit (visited_ssa, SSA_NAME_VERSION (t)(tree_check ((t), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 456, __FUNCTION__, (SSA_NAME)))->base.u.version)) |
| 457 | worklist.safe_push (t); |
| 458 | } |
| 459 | continue; |
| 460 | } |
| 461 | |
| 462 | /* Uses in stmts always executed when the region header executes |
| 463 | are fine. */ |
| 464 | if (dominated_by_p (CDI_DOMINATORS, loop->header, gimple_bb (def))) |
| 465 | continue; |
| 466 | |
| 467 | /* Handle calls and memory loads conservatively. */ |
| 468 | if (!is_gimple_assign (def) |
| 469 | || (gimple_assign_single_p (def) |
| 470 | && gimple_vuse (def))) |
| 471 | return true; |
| 472 | |
| 473 | /* Check that any SSA names used to define NAME are also fully |
| 474 | defined. */ |
| 475 | use_operand_p use_p; |
| 476 | ssa_op_iter iter; |
| 477 | FOR_EACH_SSA_USE_OPERAND (use_p, def, iter, SSA_OP_USE)for (use_p = op_iter_init_use (&(iter), def, 0x01); !op_iter_done (&(iter)); use_p = op_iter_next_use (&(iter))) |
| 478 | { |
| 479 | tree t = USE_FROM_PTR (use_p)get_use_from_ptr (use_p); |
| 480 | /* If an SSA has already been seen, it may be a loop, |
| 481 | but we can continue and ignore this use. Otherwise, |
| 482 | add the SSA_NAME to the queue and visit it later. */ |
| 483 | if (bitmap_set_bit (visited_ssa, SSA_NAME_VERSION (t)(tree_check ((t), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 483, __FUNCTION__, (SSA_NAME)))->base.u.version)) |
| 484 | worklist.safe_push (t); |
| 485 | } |
| 486 | } |
| 487 | return false; |
| 488 | } |
| 489 | |
| 490 | /* Checks whether we can unswitch LOOP on condition at end of BB -- one of its |
| 491 | basic blocks (for what it means see comments below). |
| 492 | All candidates all filled to the provided vector CANDIDATES. |
| 493 | OUTER_LOOP is updated to the innermost loop all found candidates are |
| 494 | invariant in. */ |
| 495 | |
| 496 | static void |
| 497 | find_unswitching_predicates_for_bb (basic_block bb, class loop *loop, |
| 498 | class loop *&outer_loop, |
| 499 | vec<unswitch_predicate *> &candidates, |
| 500 | unswitch_predicate *&hottest, |
| 501 | basic_block &hottest_bb) |
| 502 | { |
| 503 | gimple *last, *def; |
| 504 | tree use; |
| 505 | basic_block def_bb; |
| 506 | ssa_op_iter iter; |
| 507 | |
| 508 | /* BB must end in a simple conditional jump. */ |
| 509 | last = last_stmt (bb); |
| 510 | if (!last) |
| 511 | return; |
| 512 | |
| 513 | if (gcond *stmt = safe_dyn_cast <gcond *> (last)) |
| 514 | { |
| 515 | /* To keep the things simple, we do not directly remove the conditions, |
| 516 | but just replace tests with 0 != 0 resp. 1 != 0. Prevent the infinite |
| 517 | loop where we would unswitch again on such a condition. */ |
| 518 | if (gimple_cond_true_p (stmt) || gimple_cond_false_p (stmt)) |
| 519 | return; |
| 520 | |
| 521 | /* At least the LHS needs to be symbolic. */ |
| 522 | if (TREE_CODE (gimple_cond_lhs (stmt))((enum tree_code) (gimple_cond_lhs (stmt))->base.code) != SSA_NAME) |
| 523 | return; |
| 524 | |
| 525 | /* Condition must be invariant. */ |
| 526 | FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE)for (use = op_iter_init_tree (&(iter), stmt, 0x01); !op_iter_done (&(iter)); (void) (use = op_iter_next_tree (&(iter)) )) |
| 527 | { |
| 528 | def = SSA_NAME_DEF_STMT (use)(tree_check ((use), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 528, __FUNCTION__, (SSA_NAME)))->ssa_name.def_stmt; |
| 529 | def_bb = gimple_bb (def); |
| 530 | if (def_bb |
| 531 | && flow_bb_inside_loop_p (loop, def_bb)) |
| 532 | return; |
| 533 | /* Unswitching on undefined values would introduce undefined |
| 534 | behavior that the original program might never exercise. */ |
| 535 | if (is_maybe_undefined (use, stmt, loop)) |
| 536 | return; |
| 537 | } |
| 538 | /* Narrow OUTER_LOOP. */ |
| 539 | if (outer_loop != loop) |
| 540 | FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE)for (use = op_iter_init_tree (&(iter), stmt, 0x01); !op_iter_done (&(iter)); (void) (use = op_iter_next_tree (&(iter)) )) |
| 541 | { |
| 542 | def = SSA_NAME_DEF_STMT (use)(tree_check ((use), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 542, __FUNCTION__, (SSA_NAME)))->ssa_name.def_stmt; |
| 543 | def_bb = gimple_bb (def); |
| 544 | while (outer_loop != loop |
| 545 | && ((def_bb && flow_bb_inside_loop_p (outer_loop, def_bb)) |
| 546 | || is_maybe_undefined (use, stmt, outer_loop))) |
| 547 | outer_loop = superloop_at_depth (loop, |
| 548 | loop_depth (outer_loop) + 1); |
| 549 | } |
| 550 | |
| 551 | unswitch_predicate *predicate = new unswitch_predicate (stmt); |
| 552 | candidates.safe_push (predicate); |
| 553 | /* If we unswitch on this predicate we isolate both paths, so |
| 554 | pick the highest count for updating of the hottest predicate |
| 555 | to unswitch on first. */ |
| 556 | if (!hottest || predicate->count > hottest->count) |
| 557 | { |
| 558 | hottest = predicate; |
| 559 | hottest_bb = bb; |
| 560 | } |
| 561 | } |
| 562 | else if (gswitch *stmt = safe_dyn_cast <gswitch *> (last)) |
| 563 | { |
| 564 | unsigned nlabels = gimple_switch_num_labels (stmt); |
| 565 | tree idx = gimple_switch_index (stmt); |
| 566 | tree idx_type = TREE_TYPE (idx)((contains_struct_check ((idx), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 566, __FUNCTION__))->typed.type); |
| 567 | if (!gimple_range_ssa_p (idx) || nlabels < 1) |
| 568 | return; |
| 569 | /* Index must be invariant. */ |
| 570 | def = SSA_NAME_DEF_STMT (idx)(tree_check ((idx), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 570, __FUNCTION__, (SSA_NAME)))->ssa_name.def_stmt; |
| 571 | def_bb = gimple_bb (def); |
| 572 | if (def_bb |
| 573 | && flow_bb_inside_loop_p (loop, def_bb)) |
| 574 | return; |
| 575 | /* Unswitching on undefined values would introduce undefined |
| 576 | behavior that the original program might never exercise. */ |
| 577 | if (is_maybe_undefined (idx, stmt, loop)) |
| 578 | return; |
| 579 | /* Narrow OUTER_LOOP. */ |
| 580 | while (outer_loop != loop |
| 581 | && ((def_bb && flow_bb_inside_loop_p (outer_loop, def_bb)) |
| 582 | || is_maybe_undefined (idx, stmt, outer_loop))) |
| 583 | outer_loop = superloop_at_depth (loop, |
| 584 | loop_depth (outer_loop) + 1); |
| 585 | |
| 586 | /* Build compound expression for all outgoing edges of the switch. */ |
| 587 | auto_vec<tree, 16> preds; |
| 588 | auto_vec<int_range_max> edge_range; |
| 589 | preds.safe_grow_cleared (EDGE_COUNT (gimple_bb (stmt)->succs)vec_safe_length (gimple_bb (stmt)->succs), true); |
| 590 | edge_range.safe_grow_cleared (EDGE_COUNT (gimple_bb (stmt)->succs)vec_safe_length (gimple_bb (stmt)->succs), true); |
| 591 | edge e; |
| 592 | edge_iterator ei; |
| 593 | unsigned edge_index = 0; |
| 594 | FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)for ((ei) = ei_start_1 (&((gimple_bb (stmt)->succs))); ei_cond ((ei), &(e)); ei_next (&(ei))) |
| 595 | e->aux = (void *)(uintptr_t)edge_index++; |
| 596 | for (unsigned i = 1; i < gimple_switch_num_labels (stmt); ++i) |
| 597 | { |
| 598 | tree lab = gimple_switch_label (stmt, i); |
| 599 | tree cmp; |
| 600 | int_range<2> lab_range; |
| 601 | tree low = fold_convert (idx_type, CASE_LOW (lab))fold_convert_loc (((location_t) 0), idx_type, (*((const_cast< tree*> (tree_operand_check (((tree_check ((lab), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 601, __FUNCTION__, (CASE_LABEL_EXPR)))), (0), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 601, __FUNCTION__)))))); |
| 602 | if (CASE_HIGH (lab)(*((const_cast<tree*> (tree_operand_check (((tree_check ((lab), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 602, __FUNCTION__, (CASE_LABEL_EXPR)))), (1), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 602, __FUNCTION__))))) != NULL_TREE(tree) nullptr) |
| 603 | { |
| 604 | tree high = fold_convert (idx_type, CASE_HIGH (lab))fold_convert_loc (((location_t) 0), idx_type, (*((const_cast< tree*> (tree_operand_check (((tree_check ((lab), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 604, __FUNCTION__, (CASE_LABEL_EXPR)))), (1), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 604, __FUNCTION__)))))); |
| 605 | tree cmp1 = fold_build2 (GE_EXPR, boolean_type_node, idx, low)fold_build2_loc (((location_t) 0), GE_EXPR, global_trees[TI_BOOLEAN_TYPE ], idx, low ); |
| 606 | tree cmp2 = fold_build2 (LE_EXPR, boolean_type_node, idx, high)fold_build2_loc (((location_t) 0), LE_EXPR, global_trees[TI_BOOLEAN_TYPE ], idx, high ); |
| 607 | cmp = fold_build2 (BIT_AND_EXPR, boolean_type_node, cmp1, cmp2)fold_build2_loc (((location_t) 0), BIT_AND_EXPR, global_trees [TI_BOOLEAN_TYPE], cmp1, cmp2 ); |
| 608 | lab_range.set (low, high); |
| 609 | } |
| 610 | else |
| 611 | { |
| 612 | cmp = fold_build2 (EQ_EXPR, boolean_type_node, idx, low)fold_build2_loc (((location_t) 0), EQ_EXPR, global_trees[TI_BOOLEAN_TYPE ], idx, low ); |
| 613 | lab_range.set (low, low); |
| 614 | } |
| 615 | |
| 616 | /* Combine the expression with the existing one. */ |
| 617 | basic_block dest = label_to_block (cfun(cfun + 0), CASE_LABEL (lab)(*((const_cast<tree*> (tree_operand_check (((tree_check ((lab), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 617, __FUNCTION__, (CASE_LABEL_EXPR)))), (2), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 617, __FUNCTION__)))))); |
| 618 | e = find_edge (gimple_bb (stmt), dest); |
| 619 | tree &expr = preds[(uintptr_t)e->aux]; |
| 620 | if (expr == NULL_TREE(tree) nullptr) |
| 621 | expr = cmp; |
| 622 | else |
| 623 | expr = fold_build2 (BIT_IOR_EXPR, boolean_type_node, expr, cmp)fold_build2_loc (((location_t) 0), BIT_IOR_EXPR, global_trees [TI_BOOLEAN_TYPE], expr, cmp ); |
| 624 | edge_range[(uintptr_t)e->aux].union_ (lab_range); |
| 625 | } |
| 626 | |
| 627 | /* Now register the predicates. */ |
| 628 | for (edge_index = 0; edge_index < preds.length (); ++edge_index) |
| 629 | { |
| 630 | edge e = EDGE_SUCC (gimple_bb (stmt), edge_index)(*(gimple_bb (stmt))->succs)[(edge_index)]; |
| 631 | e->aux = NULLnullptr; |
| 632 | if (preds[edge_index] != NULL_TREE(tree) nullptr) |
| 633 | { |
| 634 | unswitch_predicate *predicate |
| 635 | = new unswitch_predicate (preds[edge_index], idx, |
| 636 | edge_index, e, |
| 637 | edge_range[edge_index]); |
| 638 | candidates.safe_push (predicate); |
| 639 | if (!hottest || predicate->count > hottest->count) |
| 640 | { |
| 641 | hottest = predicate; |
| 642 | hottest_bb = bb; |
| 643 | } |
| 644 | } |
| 645 | } |
| 646 | } |
| 647 | } |
| 648 | |
| 649 | /* Merge ranges for the last item of PREDICATE_PATH with a predicate |
| 650 | that shared the same LHS. */ |
| 651 | |
| 652 | static void |
| 653 | merge_last (predicate_vector &predicate_path) |
| 654 | { |
| 655 | unswitch_predicate *last_predicate = predicate_path.last ().first; |
| 656 | |
| 657 | for (int i = predicate_path.length () - 2; i >= 0; i--) |
| 658 | { |
| 659 | unswitch_predicate *predicate = predicate_path[i].first; |
| 660 | bool true_edge = predicate_path[i].second; |
| 661 | |
| 662 | if (operand_equal_p (predicate->lhs, last_predicate->lhs, 0)) |
| 663 | { |
| 664 | irange &other = (true_edge ? predicate->merged_true_range |
| 665 | : predicate->merged_false_range); |
| 666 | last_predicate->merged_true_range.intersect (other); |
| 667 | last_predicate->merged_false_range.intersect (other); |
| 668 | return; |
| 669 | } |
| 670 | } |
| 671 | } |
| 672 | |
| 673 | /* Add PREDICATE to PREDICATE_PATH on TRUE_EDGE. */ |
| 674 | |
| 675 | static void |
| 676 | add_predicate_to_path (predicate_vector &predicate_path, |
| 677 | unswitch_predicate *predicate, bool true_edge) |
| 678 | { |
| 679 | predicate->copy_merged_ranges (); |
| 680 | predicate_path.safe_push (std::make_pair (predicate, true_edge)); |
| 681 | merge_last (predicate_path); |
| 682 | } |
| 683 | |
| 684 | static bool |
| 685 | find_range_for_lhs (predicate_vector &predicate_path, tree lhs, |
| 686 | int_range_max &range) |
| 687 | { |
| 688 | for (int i = predicate_path.length () - 1; i >= 0; i--) |
| 689 | { |
| 690 | unswitch_predicate *predicate = predicate_path[i].first; |
| 691 | bool true_edge = predicate_path[i].second; |
| 692 | |
| 693 | if (operand_equal_p (predicate->lhs, lhs, 0)) |
| 694 | { |
| 695 | range = (true_edge ? predicate->merged_true_range |
| 696 | : predicate->merged_false_range); |
| 697 | return !range.undefined_p (); |
| 698 | } |
| 699 | } |
| 700 | |
| 701 | return false; |
| 702 | } |
| 703 | |
| 704 | /* Simplifies STMT using the predicate we unswitched on which is the last |
| 705 | in PREDICATE_PATH. For switch statements add newly unreachable edges |
| 706 | to IGNORED_EDGES (but do not set IGNORED_EDGE_FLAG on them). */ |
| 707 | |
| 708 | static tree |
| 709 | evaluate_control_stmt_using_entry_checks (gimple *stmt, |
| 710 | predicate_vector &predicate_path, |
| 711 | int ignored_edge_flag, |
| 712 | hash_set<edge> *ignored_edges) |
| 713 | { |
| 714 | unswitch_predicate *last_predicate = predicate_path.last ().first; |
| 715 | bool true_edge = predicate_path.last ().second; |
| 716 | |
| 717 | if (gcond *cond = dyn_cast<gcond *> (stmt)) |
| 718 | { |
| 719 | tree lhs = gimple_cond_lhs (cond); |
| 720 | if (!operand_equal_p (lhs, last_predicate->lhs)) |
| 721 | return NULL_TREE(tree) nullptr; |
| 722 | /* Try a symbolic match which works for floating point and fully |
| 723 | symbolic conditions. */ |
| 724 | if (gimple_cond_code (cond) == TREE_CODE (last_predicate->condition)((enum tree_code) (last_predicate->condition)->base.code ) |
| 725 | && operand_equal_p (gimple_cond_rhs (cond), |
| 726 | TREE_OPERAND (last_predicate->condition, 1)(*((const_cast<tree*> (tree_operand_check ((last_predicate ->condition), (1), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 726, __FUNCTION__))))))) |
| 727 | return true_edge ? boolean_true_nodeglobal_trees[TI_BOOLEAN_TRUE] : boolean_false_nodeglobal_trees[TI_BOOLEAN_FALSE]; |
| 728 | /* Else try ranger if it supports LHS. */ |
| 729 | else if (irange::supports_p (TREE_TYPE (lhs)((contains_struct_check ((lhs), (TS_TYPED), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 729, __FUNCTION__))->typed.type))) |
| 730 | { |
| 731 | int_range<2> r; |
| 732 | int_range_max path_range; |
| 733 | |
| 734 | if (find_range_for_lhs (predicate_path, lhs, path_range) |
| 735 | && fold_range (r, cond, path_range) |
| 736 | && r.singleton_p ()) |
| 737 | return r.zero_p () ? boolean_false_nodeglobal_trees[TI_BOOLEAN_FALSE] : boolean_true_nodeglobal_trees[TI_BOOLEAN_TRUE]; |
| 738 | } |
| 739 | } |
| 740 | else if (gswitch *swtch = dyn_cast<gswitch *> (stmt)) |
| 741 | { |
| 742 | unsigned nlabels = gimple_switch_num_labels (swtch); |
| 743 | |
| 744 | tree idx = gimple_switch_index (swtch); |
| 745 | |
| 746 | /* Already folded switch. */ |
| 747 | if (TREE_CONSTANT (idx)((non_type_check ((idx), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 747, __FUNCTION__))->base.constant_flag)) |
| 748 | return NULL_TREE(tree) nullptr; |
| 749 | |
| 750 | int_range_max path_range; |
| 751 | if (!find_range_for_lhs (predicate_path, idx, path_range)) |
| 752 | return NULL_TREE(tree) nullptr; |
| 753 | |
| 754 | tree result = NULL_TREE(tree) nullptr; |
| 755 | edge single_edge = NULLnullptr; |
| 756 | for (unsigned i = 0; i < nlabels; ++i) |
| 757 | { |
| 758 | tree lab = gimple_switch_label (swtch, i); |
| 759 | basic_block dest = label_to_block (cfun(cfun + 0), CASE_LABEL (lab)(*((const_cast<tree*> (tree_operand_check (((tree_check ((lab), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 759, __FUNCTION__, (CASE_LABEL_EXPR)))), (2), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 759, __FUNCTION__)))))); |
| 760 | edge e = find_edge (gimple_bb (stmt), dest); |
| 761 | if (e->flags & ignored_edge_flag) |
| 762 | continue; |
| 763 | |
| 764 | int_range_max r; |
| 765 | if (!ranger->gori ().outgoing_edge_range_p (r, e, idx, |
| 766 | *get_global_range_query ())) |
| 767 | continue; |
| 768 | r.intersect (path_range); |
| 769 | if (r.undefined_p ()) |
| 770 | ignored_edges->add (e); |
| 771 | else |
| 772 | { |
| 773 | if (!single_edge) |
| 774 | { |
| 775 | single_edge = e; |
| 776 | result = CASE_LOW (lab)(*((const_cast<tree*> (tree_operand_check (((tree_check ((lab), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 776, __FUNCTION__, (CASE_LABEL_EXPR)))), (0), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 776, __FUNCTION__))))); |
| 777 | } |
| 778 | else if (single_edge != e) |
| 779 | result = NULLnullptr; |
| 780 | } |
| 781 | } |
| 782 | |
| 783 | /* Only one edge from the switch is alive. */ |
| 784 | if (single_edge && result) |
| 785 | return result; |
| 786 | } |
| 787 | |
| 788 | return NULL_TREE(tree) nullptr; |
| 789 | } |
| 790 | |
| 791 | /* Simplify LOOP based on PREDICATE_PATH where dead edges are properly |
| 792 | marked. */ |
| 793 | |
| 794 | static bool |
| 795 | simplify_loop_version (class loop *loop, predicate_vector &predicate_path, |
| 796 | int ignored_edge_flag, bitmap handled) |
| 797 | { |
| 798 | bool changed = false; |
| 799 | basic_block *bbs = get_loop_body (loop); |
| 800 | |
| 801 | hash_set<edge> ignored_edges; |
| 802 | for (unsigned i = 0; i != loop->num_nodes; i++) |
| 803 | { |
| 804 | vec<unswitch_predicate *> &predicates = get_predicates_for_bb (bbs[i]); |
| 805 | if (predicates.is_empty ()) |
| 806 | continue; |
| 807 | |
| 808 | gimple *stmt = last_stmt (bbs[i]); |
| 809 | tree folded = evaluate_control_stmt_using_entry_checks (stmt, |
| 810 | predicate_path, |
| 811 | ignored_edge_flag, |
| 812 | &ignored_edges); |
| 813 | |
| 814 | if (gcond *cond = dyn_cast<gcond *> (stmt)) |
| 815 | { |
| 816 | if (folded) |
| 817 | { |
| 818 | /* Remove path. */ |
| 819 | if (integer_nonzerop (folded)) |
| 820 | gimple_cond_set_condition_from_tree (cond, boolean_true_nodeglobal_trees[TI_BOOLEAN_TRUE]); |
| 821 | else |
| 822 | gimple_cond_set_condition_from_tree (cond, boolean_false_nodeglobal_trees[TI_BOOLEAN_FALSE]); |
| 823 | |
| 824 | gcc_assert (predicates.length () == 1)((void)(!(predicates.length () == 1) ? fancy_abort ("/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 824, __FUNCTION__), 0 : 0)); |
| 825 | bitmap_set_bit (handled, predicates[0]->num); |
| 826 | |
| 827 | update_stmt (cond); |
| 828 | changed = true; |
| 829 | } |
| 830 | } |
| 831 | else if (gswitch *swtch = dyn_cast<gswitch *> (stmt)) |
| 832 | { |
| 833 | edge e; |
| 834 | edge_iterator ei; |
| 835 | FOR_EACH_EDGE (e, ei, bbs[i]->succs)for ((ei) = ei_start_1 (&((bbs[i]->succs))); ei_cond ( (ei), &(e)); ei_next (&(ei))) |
| 836 | if (ignored_edges.contains (e)) |
| 837 | e->flags |= ignored_edge_flag; |
| 838 | |
| 839 | for (unsigned j = 0; j < predicates.length (); j++) |
| 840 | { |
| 841 | edge e = EDGE_SUCC (bbs[i], predicates[j]->edge_index)(*(bbs[i])->succs)[(predicates[j]->edge_index)]; |
| 842 | if (ignored_edges.contains (e)) |
| 843 | bitmap_set_bit (handled, predicates[j]->num); |
| 844 | } |
| 845 | |
| 846 | if (folded) |
| 847 | { |
| 848 | gimple_switch_set_index (swtch, folded); |
| 849 | update_stmt (swtch); |
| 850 | changed = true; |
| 851 | } |
| 852 | } |
| 853 | } |
| 854 | |
| 855 | free (bbs); |
| 856 | return changed; |
| 857 | } |
| 858 | |
| 859 | /* Evaluate reachable blocks in LOOP and call VISIT on them, aborting the |
| 860 | DFS walk if VISIT returns true. When PREDICATE_PATH is specified then |
| 861 | take into account that when computing reachability, otherwise just |
| 862 | look at the simplified state and IGNORED_EDGE_FLAG. */ |
| 863 | |
| 864 | template <typename VisitOp> |
| 865 | static void |
| 866 | evaluate_bbs (class loop *loop, predicate_vector *predicate_path, |
| 867 | int ignored_edge_flag, VisitOp visit) |
| 868 | { |
| 869 | auto_bb_flag reachable_flag (cfun(cfun + 0)); |
| 870 | auto_vec<basic_block, 10> worklist (loop->num_nodes); |
| 871 | auto_vec<basic_block, 10> reachable (loop->num_nodes); |
| 872 | hash_set<edge> ignored_edges; |
| 873 | |
| 874 | loop->header->flags |= reachable_flag; |
| 875 | worklist.quick_push (loop->header); |
| 876 | reachable.safe_push (loop->header); |
| 877 | |
| 878 | while (!worklist.is_empty ()) |
| 879 | { |
| 880 | edge e; |
| 881 | edge_iterator ei; |
| 882 | int flags = ignored_edge_flag; |
| 883 | basic_block bb = worklist.pop (); |
| 884 | |
| 885 | if (visit (bb)) |
| 886 | break; |
| 887 | |
| 888 | gimple *last = last_stmt (bb); |
| 889 | if (gcond *cond = safe_dyn_cast <gcond *> (last)) |
| 890 | { |
| 891 | if (gimple_cond_true_p (cond)) |
| 892 | flags = EDGE_FALSE_VALUE; |
| 893 | else if (gimple_cond_false_p (cond)) |
| 894 | flags = EDGE_TRUE_VALUE; |
| 895 | else if (predicate_path) |
| 896 | { |
| 897 | tree res; |
| 898 | if (!get_predicates_for_bb (bb).is_empty () |
| 899 | && (res = evaluate_control_stmt_using_entry_checks |
| 900 | (cond, *predicate_path, ignored_edge_flag, |
| 901 | &ignored_edges))) |
| 902 | flags = (integer_nonzerop (res) |
| 903 | ? EDGE_FALSE_VALUE : EDGE_TRUE_VALUE); |
| 904 | } |
| 905 | } |
| 906 | else if (gswitch *swtch = safe_dyn_cast<gswitch *> (last)) |
| 907 | if (predicate_path |
| 908 | && !get_predicates_for_bb (bb).is_empty ()) |
| 909 | evaluate_control_stmt_using_entry_checks (swtch, *predicate_path, |
| 910 | ignored_edge_flag, |
| 911 | &ignored_edges); |
| 912 | |
| 913 | /* Note that for the moment we do not account reachable conditions |
| 914 | which are simplified to take a known edge as zero size nor |
| 915 | are we accounting for the required addition of the versioning |
| 916 | condition. Those should cancel out conservatively. */ |
| 917 | |
| 918 | FOR_EACH_EDGE (e, ei, bb->succs)for ((ei) = ei_start_1 (&((bb->succs))); ei_cond ((ei) , &(e)); ei_next (&(ei))) |
| 919 | { |
| 920 | basic_block dest = e->dest; |
| 921 | |
| 922 | if (flow_bb_inside_loop_p (loop, dest) |
| 923 | && !(dest->flags & reachable_flag) |
| 924 | && !(e->flags & flags) |
| 925 | && !ignored_edges.contains (e)) |
| 926 | { |
| 927 | dest->flags |= reachable_flag; |
| 928 | worklist.safe_push (dest); |
| 929 | reachable.safe_push (dest); |
| 930 | } |
| 931 | } |
| 932 | } |
| 933 | |
| 934 | /* Clear the flag from basic blocks. */ |
| 935 | while (!reachable.is_empty ()) |
| 936 | reachable.pop ()->flags &= ~reachable_flag; |
| 937 | } |
| 938 | |
| 939 | /* Evaluate how many instruction will we have if we unswitch LOOP (with BBS) |
| 940 | based on PREDICATE predicate (using PREDICATE_PATH). Store the |
| 941 | result in TRUE_SIZE and FALSE_SIZE. */ |
| 942 | |
| 943 | static void |
| 944 | evaluate_loop_insns_for_predicate (class loop *loop, |
| 945 | predicate_vector &predicate_path, |
| 946 | unswitch_predicate *predicate, |
| 947 | int ignored_edge_flag, |
| 948 | unsigned *true_size, unsigned *false_size) |
| 949 | { |
| 950 | unsigned size = 0; |
| 951 | auto sum_size = [&](basic_block bb) -> bool |
| 952 | { size += (uintptr_t)bb->aux; return false; }; |
| 953 | |
| 954 | add_predicate_to_path (predicate_path, predicate, true); |
| 955 | evaluate_bbs (loop, &predicate_path, ignored_edge_flag, sum_size); |
| 956 | predicate_path.pop (); |
| 957 | unsigned true_loop_cost = size; |
| 958 | |
| 959 | size = 0; |
| 960 | add_predicate_to_path (predicate_path, predicate, false); |
| 961 | evaluate_bbs (loop, &predicate_path, ignored_edge_flag, sum_size); |
| 962 | predicate_path.pop (); |
| 963 | unsigned false_loop_cost = size; |
| 964 | |
| 965 | *true_size = true_loop_cost; |
| 966 | *false_size = false_loop_cost; |
| 967 | } |
| 968 | |
| 969 | /* Unswitch single LOOP. PREDICATE_PATH contains so far used predicates |
| 970 | for unswitching. BUDGET is number of instruction for which we can increase |
| 971 | the loop and is updated when unswitching occurs. If HOTTEST is not |
| 972 | NULL then pick this candidate as the one to unswitch on. */ |
| 973 | |
| 974 | static bool |
| 975 | tree_unswitch_single_loop (class loop *loop, dump_user_location_t loc, |
| 976 | predicate_vector &predicate_path, |
| 977 | unsigned loop_size, unsigned &budget, |
| 978 | int ignored_edge_flag, bitmap handled, |
| 979 | unswitch_predicate *hottest, basic_block hottest_bb) |
| 980 | { |
| 981 | class loop *nloop; |
| 982 | bool changed = false; |
| 983 | unswitch_predicate *predicate = NULLnullptr; |
| 984 | basic_block predicate_bb = NULLnullptr; |
| 985 | unsigned true_size = 0, false_size = 0; |
| 986 | |
| 987 | auto check_predicates = [&](basic_block bb) -> bool |
| 988 | { |
| 989 | for (auto pred : get_predicates_for_bb (bb)) |
| 990 | { |
| 991 | if (bitmap_bit_p (handled, pred->num)) |
| 992 | continue; |
| 993 | |
| 994 | evaluate_loop_insns_for_predicate (loop, predicate_path, |
| 995 | pred, ignored_edge_flag, |
| 996 | &true_size, &false_size); |
| 997 | |
| 998 | /* We'll get LOOP replaced with a simplified version according |
| 999 | to PRED estimated to TRUE_SIZE and a copy simplified |
| 1000 | according to the inverted PRED estimated to FALSE_SIZE. */ |
| 1001 | if (true_size + false_size < budget + loop_size) |
| 1002 | { |
| 1003 | predicate = pred; |
| 1004 | predicate_bb = bb; |
| 1005 | |
| 1006 | /* There are cases where true_size and false_size add up to |
| 1007 | less than the original loop_size. We do not want to |
| 1008 | grow the remaining budget because of that. */ |
| 1009 | if (true_size + false_size > loop_size) |
| 1010 | budget -= (true_size + false_size - loop_size); |
| 1011 | |
| 1012 | /* FIXME: right now we select first candidate, but we can |
| 1013 | choose the cheapest or hottest one. */ |
| 1014 | return true; |
| 1015 | } |
| 1016 | else if (dump_enabled_p ()) |
| 1017 | dump_printf_loc (MSG_NOTE, loc, |
| 1018 | "not unswitching condition, cost too big " |
| 1019 | "(%u insns copied to %u and %u)\n", loop_size, |
| 1020 | true_size, false_size); |
| 1021 | } |
| 1022 | return false; |
| 1023 | }; |
| 1024 | |
| 1025 | if (hottest) |
| 1026 | { |
| 1027 | predicate = hottest; |
| 1028 | predicate_bb = hottest_bb; |
| 1029 | } |
| 1030 | else |
| 1031 | /* Check predicates of reachable blocks. */ |
| 1032 | evaluate_bbs (loop, NULLnullptr, ignored_edge_flag, check_predicates); |
| 1033 | |
| 1034 | if (predicate != NULLnullptr) |
| 1035 | { |
| 1036 | if (!dbg_cnt (loop_unswitch)) |
| 1037 | goto exit; |
| 1038 | |
| 1039 | if (dump_enabled_p ()) |
| 1040 | { |
| 1041 | dump_printf_loc (MSG_OPTIMIZED_LOCATIONS, loc, |
| 1042 | "unswitching %sloop %d on %qs with condition: %T\n", |
| 1043 | loop->inner ? "outer " : "", |
| 1044 | loop->num, predicate->switch_p ? "switch" : "if", |
| 1045 | predicate->condition); |
| 1046 | dump_printf_loc (MSG_NOTE, loc, |
| 1047 | "optimized sizes estimated to %u (true) " |
| 1048 | "and %u (false) from original size %u\n", |
| 1049 | true_size, false_size, loop_size); |
| 1050 | } |
| 1051 | |
| 1052 | bitmap_set_bit (handled, predicate->num); |
| 1053 | initialize_original_copy_tables (); |
| 1054 | /* Unswitch the loop on this condition. */ |
| 1055 | nloop = tree_unswitch_loop (loop, EDGE_SUCC (predicate_bb,(*(predicate_bb)->succs)[(predicate->edge_index)] |
| 1056 | predicate->edge_index)(*(predicate_bb)->succs)[(predicate->edge_index)], |
| 1057 | predicate->condition); |
| 1058 | if (!nloop) |
| 1059 | { |
| 1060 | free_original_copy_tables (); |
| 1061 | goto exit; |
| 1062 | } |
| 1063 | |
| 1064 | /* Copy BB costs. */ |
| 1065 | basic_block *bbs2 = get_loop_body (nloop); |
| 1066 | for (unsigned i = 0; i < nloop->num_nodes; i++) |
| 1067 | bbs2[i]->aux = get_bb_original (bbs2[i])->aux; |
| 1068 | free (bbs2); |
| 1069 | |
| 1070 | free_original_copy_tables (); |
| 1071 | |
| 1072 | /* Update the SSA form after unswitching. */ |
| 1073 | update_ssa (TODO_update_ssa_no_phi(1 << 12)); |
| 1074 | |
| 1075 | /* Invoke itself on modified loops. */ |
| 1076 | bitmap handled_copy = BITMAP_ALLOCbitmap_alloc (NULLnullptr); |
| 1077 | bitmap_copy (handled_copy, handled); |
| 1078 | add_predicate_to_path (predicate_path, predicate, false); |
| 1079 | changed |= simplify_loop_version (nloop, predicate_path, |
| 1080 | ignored_edge_flag, handled_copy); |
| 1081 | tree_unswitch_single_loop (nloop, loc, predicate_path, |
| 1082 | false_size, budget, |
| 1083 | ignored_edge_flag, handled_copy); |
| 1084 | predicate_path.pop (); |
| 1085 | BITMAP_FREE (handled_copy)((void) (bitmap_obstack_free ((bitmap) handled_copy), (handled_copy ) = (bitmap) nullptr)); |
| 1086 | |
| 1087 | /* FIXME: After unwinding above we have to reset all ->handled |
| 1088 | flags as otherwise we fail to realize unswitching opportunities |
| 1089 | in the below recursion. See gcc.dg/loop-unswitch-16.c */ |
| 1090 | add_predicate_to_path (predicate_path, predicate, true); |
| 1091 | changed |= simplify_loop_version (loop, predicate_path, |
Value stored to 'changed' is never read | |
| 1092 | ignored_edge_flag, handled); |
| 1093 | tree_unswitch_single_loop (loop, loc, predicate_path, |
| 1094 | true_size, budget, |
| 1095 | ignored_edge_flag, handled); |
| 1096 | predicate_path.pop (); |
| 1097 | changed = true; |
| 1098 | } |
| 1099 | |
| 1100 | exit: |
| 1101 | return changed; |
| 1102 | } |
| 1103 | |
| 1104 | /* Unswitch a LOOP w.r. to given EDGE_TRUE. We only support unswitching of |
| 1105 | innermost loops. COND is the condition determining which loop is entered; |
| 1106 | the new loop is entered if COND is true. Returns NULL if impossible, new |
| 1107 | loop otherwise. */ |
| 1108 | |
| 1109 | static class loop * |
| 1110 | tree_unswitch_loop (class loop *loop, edge edge_true, tree cond) |
| 1111 | { |
| 1112 | /* Some sanity checking. */ |
| 1113 | gcc_assert (flow_bb_inside_loop_p (loop, edge_true->src))((void)(!(flow_bb_inside_loop_p (loop, edge_true->src)) ? fancy_abort ("/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 1113, __FUNCTION__), 0 : 0)); |
| 1114 | gcc_assert (EDGE_COUNT (edge_true->src->succs) >= 2)((void)(!(vec_safe_length (edge_true->src->succs) >= 2) ? fancy_abort ("/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 1114, __FUNCTION__), 0 : 0)); |
| 1115 | |
| 1116 | profile_probability prob_true = edge_true->probability; |
| 1117 | return loop_version (loop, unshare_expr (cond), |
| 1118 | NULLnullptr, prob_true, |
| 1119 | prob_true.invert (), |
| 1120 | prob_true, prob_true.invert (), |
| 1121 | false); |
| 1122 | } |
| 1123 | |
| 1124 | /* Unswitch outer loops by hoisting invariant guard on |
| 1125 | inner loop without code duplication. */ |
| 1126 | static bool |
| 1127 | tree_unswitch_outer_loop (class loop *loop) |
| 1128 | { |
| 1129 | edge exit, guard; |
| 1130 | HOST_WIDE_INTlong iterations; |
| 1131 | |
| 1132 | gcc_assert (loop->inner)((void)(!(loop->inner) ? fancy_abort ("/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 1132, __FUNCTION__), 0 : 0)); |
| 1133 | if (loop->inner->next) |
| 1134 | return false; |
| 1135 | /* Accept loops with single exit only which is not from inner loop. */ |
| 1136 | exit = single_exit (loop); |
| 1137 | if (!exit || exit->src->loop_father != loop) |
| 1138 | return false; |
| 1139 | /* Check that phi argument of exit edge is not defined inside loop. */ |
| 1140 | if (!check_exit_phi (loop)) |
| 1141 | return false; |
| 1142 | /* If the loop is not expected to iterate, there is no need |
| 1143 | for unswitching. */ |
| 1144 | iterations = estimated_loop_iterations_int (loop); |
| 1145 | if (iterations < 0) |
| 1146 | iterations = likely_max_loop_iterations_int (loop); |
| 1147 | if (iterations >= 0 && iterations <= 1) |
| 1148 | { |
| 1149 | if (dump_enabled_p ()) |
| 1150 | dump_printf_loc (MSG_MISSED_OPTIMIZATION, find_loop_location (loop), |
| 1151 | "Not unswitching, loop is not expected" |
| 1152 | " to iterate\n"); |
| 1153 | return false; |
| 1154 | } |
| 1155 | |
| 1156 | bool changed = false; |
| 1157 | auto_vec<gimple *> dbg_to_reset; |
| 1158 | while ((guard = find_loop_guard (loop, dbg_to_reset))) |
| 1159 | { |
| 1160 | hoist_guard (loop, guard); |
| 1161 | for (gimple *debug_stmt : dbg_to_reset) |
| 1162 | { |
| 1163 | gimple_debug_bind_reset_value (debug_stmt); |
| 1164 | update_stmt (debug_stmt); |
| 1165 | } |
| 1166 | dbg_to_reset.truncate (0); |
| 1167 | changed = true; |
| 1168 | } |
| 1169 | return changed; |
| 1170 | } |
| 1171 | |
| 1172 | /* Checks if the body of the LOOP is within an invariant guard. If this |
| 1173 | is the case, returns the edge that jumps over the real body of the loop, |
| 1174 | otherwise returns NULL. */ |
| 1175 | |
| 1176 | static edge |
| 1177 | find_loop_guard (class loop *loop, vec<gimple *> &dbg_to_reset) |
| 1178 | { |
| 1179 | basic_block header = loop->header; |
| 1180 | edge guard_edge, te, fe; |
| 1181 | basic_block *body = NULLnullptr; |
| 1182 | unsigned i; |
| 1183 | tree use; |
| 1184 | ssa_op_iter iter; |
| 1185 | |
| 1186 | /* We check for the following situation: |
| 1187 | |
| 1188 | while (1) |
| 1189 | { |
| 1190 | [header]] |
| 1191 | loop_phi_nodes; |
| 1192 | something1; |
| 1193 | if (cond1) |
| 1194 | body; |
| 1195 | nvar = phi(orig, bvar) ... for all variables changed in body; |
| 1196 | [guard_end] |
| 1197 | something2; |
| 1198 | if (cond2) |
| 1199 | break; |
| 1200 | something3; |
| 1201 | } |
| 1202 | |
| 1203 | where: |
| 1204 | |
| 1205 | 1) cond1 is loop invariant |
| 1206 | 2) If cond1 is false, then the loop is essentially empty; i.e., |
| 1207 | a) nothing in something1, something2 and something3 has side |
| 1208 | effects |
| 1209 | b) anything defined in something1, something2 and something3 |
| 1210 | is not used outside of the loop. */ |
| 1211 | |
| 1212 | gcond *cond; |
| 1213 | do |
| 1214 | { |
| 1215 | basic_block next = NULLnullptr; |
| 1216 | if (single_succ_p (header)) |
| 1217 | next = single_succ (header); |
| 1218 | else |
| 1219 | { |
| 1220 | cond = safe_dyn_cast <gcond *> (last_stmt (header)); |
| 1221 | if (! cond) |
| 1222 | return NULLnullptr; |
| 1223 | extract_true_false_edges_from_block (header, &te, &fe); |
| 1224 | /* Make sure to skip earlier hoisted guards that are left |
| 1225 | in place as if (true). */ |
| 1226 | if (gimple_cond_true_p (cond)) |
| 1227 | next = te->dest; |
| 1228 | else if (gimple_cond_false_p (cond)) |
| 1229 | next = fe->dest; |
| 1230 | else |
| 1231 | break; |
| 1232 | } |
| 1233 | /* Never traverse a backedge. */ |
| 1234 | if (header->loop_father->header == next) |
| 1235 | return NULLnullptr; |
| 1236 | header = next; |
| 1237 | } |
| 1238 | while (1); |
| 1239 | if (!flow_bb_inside_loop_p (loop, te->dest) |
| 1240 | || !flow_bb_inside_loop_p (loop, fe->dest)) |
| 1241 | return NULLnullptr; |
| 1242 | |
| 1243 | if (just_once_each_iteration_p (loop, te->dest) |
| 1244 | || (single_succ_p (te->dest) |
| 1245 | && just_once_each_iteration_p (loop, single_succ (te->dest)))) |
| 1246 | { |
| 1247 | if (just_once_each_iteration_p (loop, fe->dest)) |
| 1248 | return NULLnullptr; |
| 1249 | guard_edge = te; |
| 1250 | } |
| 1251 | else if (just_once_each_iteration_p (loop, fe->dest) |
| 1252 | || (single_succ_p (fe->dest) |
| 1253 | && just_once_each_iteration_p (loop, single_succ (fe->dest)))) |
| 1254 | guard_edge = fe; |
| 1255 | else |
| 1256 | return NULLnullptr; |
| 1257 | |
| 1258 | dump_user_location_t loc = find_loop_location (loop); |
| 1259 | |
| 1260 | /* Guard edge must skip inner loop. */ |
| 1261 | if (!dominated_by_p (CDI_DOMINATORS, loop->inner->header, |
| 1262 | guard_edge == fe ? te->dest : fe->dest)) |
| 1263 | { |
| 1264 | if (dump_enabled_p ()) |
| 1265 | dump_printf_loc (MSG_MISSED_OPTIMIZATION, loc, |
| 1266 | "Guard edge %d --> %d is not around the loop!\n", |
| 1267 | guard_edge->src->index, guard_edge->dest->index); |
| 1268 | return NULLnullptr; |
| 1269 | } |
| 1270 | if (guard_edge->dest == loop->latch) |
| 1271 | { |
| 1272 | if (dump_enabled_p ()) |
| 1273 | dump_printf_loc (MSG_MISSED_OPTIMIZATION, loc, |
| 1274 | "Guard edge destination is loop latch.\n"); |
| 1275 | return NULLnullptr; |
| 1276 | } |
| 1277 | |
| 1278 | if (dump_enabled_p ()) |
| 1279 | dump_printf_loc (MSG_NOTE, loc, |
| 1280 | "Considering guard %d -> %d in loop %d\n", |
| 1281 | guard_edge->src->index, guard_edge->dest->index, |
| 1282 | loop->num); |
| 1283 | /* Check if condition operands do not have definitions inside loop since |
| 1284 | any bb copying is not performed. */ |
| 1285 | FOR_EACH_SSA_TREE_OPERAND (use, cond, iter, SSA_OP_USE)for (use = op_iter_init_tree (&(iter), cond, 0x01); !op_iter_done (&(iter)); (void) (use = op_iter_next_tree (&(iter)) )) |
| 1286 | { |
| 1287 | gimple *def = SSA_NAME_DEF_STMT (use)(tree_check ((use), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 1287, __FUNCTION__, (SSA_NAME)))->ssa_name.def_stmt; |
| 1288 | basic_block def_bb = gimple_bb (def); |
| 1289 | if (def_bb |
| 1290 | && flow_bb_inside_loop_p (loop, def_bb)) |
| 1291 | { |
| 1292 | if (dump_enabled_p ()) |
| 1293 | dump_printf_loc (MSG_NOTE, loc, "guard operands have definitions" |
| 1294 | " inside loop\n"); |
| 1295 | return NULLnullptr; |
| 1296 | } |
| 1297 | } |
| 1298 | |
| 1299 | body = get_loop_body (loop); |
| 1300 | for (i = 0; i < loop->num_nodes; i++) |
| 1301 | { |
| 1302 | basic_block bb = body[i]; |
| 1303 | if (bb->loop_father != loop) |
| 1304 | continue; |
| 1305 | if (bb->flags & BB_IRREDUCIBLE_LOOP) |
| 1306 | { |
| 1307 | if (dump_enabled_p ()) |
| 1308 | dump_printf_loc (MSG_MISSED_OPTIMIZATION, loc, |
| 1309 | "Block %d is marked as irreducible in loop\n", |
| 1310 | bb->index); |
| 1311 | guard_edge = NULLnullptr; |
| 1312 | goto end; |
| 1313 | } |
| 1314 | if (!empty_bb_without_guard_p (loop, bb, dbg_to_reset)) |
| 1315 | { |
| 1316 | if (dump_enabled_p ()) |
| 1317 | dump_printf_loc (MSG_MISSED_OPTIMIZATION, loc, |
| 1318 | "Block %d has side effects\n", bb->index); |
| 1319 | guard_edge = NULLnullptr; |
| 1320 | goto end; |
| 1321 | } |
| 1322 | } |
| 1323 | |
| 1324 | if (dump_enabled_p ()) |
| 1325 | dump_printf_loc (MSG_NOTE, loc, |
| 1326 | "suitable to hoist\n"); |
| 1327 | end: |
| 1328 | if (body) |
| 1329 | free (body); |
| 1330 | return guard_edge; |
| 1331 | } |
| 1332 | |
| 1333 | /* Returns true if |
| 1334 | 1) no statement in BB has side effects |
| 1335 | 2) assuming that edge GUARD is always taken, all definitions in BB |
| 1336 | are noy used outside of the loop. |
| 1337 | KNOWN_INVARIANTS is a set of ssa names we know to be invariant, and |
| 1338 | PROCESSED is a set of ssa names for that we already tested whether they |
| 1339 | are invariant or not. Uses in debug stmts outside of the loop are |
| 1340 | pushed to DBG_TO_RESET. */ |
| 1341 | |
| 1342 | static bool |
| 1343 | empty_bb_without_guard_p (class loop *loop, basic_block bb, |
| 1344 | vec<gimple *> &dbg_to_reset) |
| 1345 | { |
| 1346 | basic_block exit_bb = single_exit (loop)->src; |
| 1347 | bool may_be_used_outside = (bb == exit_bb |
| 1348 | || !dominated_by_p (CDI_DOMINATORS, bb, exit_bb)); |
| 1349 | tree name; |
| 1350 | ssa_op_iter op_iter; |
| 1351 | |
| 1352 | /* Phi nodes do not have side effects, but their results might be used |
| 1353 | outside of the loop. */ |
| 1354 | if (may_be_used_outside) |
| 1355 | { |
| 1356 | for (gphi_iterator gsi = gsi_start_phis (bb); |
| 1357 | !gsi_end_p (gsi); gsi_next (&gsi)) |
| 1358 | { |
| 1359 | gphi *phi = gsi.phi (); |
| 1360 | name = PHI_RESULT (phi)get_def_from_ptr (gimple_phi_result_ptr (phi)); |
| 1361 | if (virtual_operand_p (name)) |
| 1362 | continue; |
| 1363 | |
| 1364 | if (used_outside_loop_p (loop, name, dbg_to_reset)) |
| 1365 | return false; |
| 1366 | } |
| 1367 | } |
| 1368 | |
| 1369 | for (gimple_stmt_iterator gsi = gsi_start_bb (bb); |
| 1370 | !gsi_end_p (gsi); gsi_next (&gsi)) |
| 1371 | { |
| 1372 | gimple *stmt = gsi_stmt (gsi); |
| 1373 | if (is_gimple_debug (stmt)) |
| 1374 | continue; |
| 1375 | |
| 1376 | if (gimple_has_side_effects (stmt)) |
| 1377 | return false; |
| 1378 | |
| 1379 | if (gimple_vdef(stmt)) |
| 1380 | return false; |
| 1381 | |
| 1382 | FOR_EACH_SSA_TREE_OPERAND (name, stmt, op_iter, SSA_OP_DEF)for (name = op_iter_init_tree (&(op_iter), stmt, 0x02); ! op_iter_done (&(op_iter)); (void) (name = op_iter_next_tree (&(op_iter)))) |
| 1383 | { |
| 1384 | if (may_be_used_outside |
| 1385 | && used_outside_loop_p (loop, name, dbg_to_reset)) |
| 1386 | return false; |
| 1387 | } |
| 1388 | } |
| 1389 | return true; |
| 1390 | } |
| 1391 | |
| 1392 | /* Return true if NAME is used outside of LOOP. Pushes debug stmts that |
| 1393 | have such uses to DBG_TO_RESET but do not consider such uses. */ |
| 1394 | |
| 1395 | static bool |
| 1396 | used_outside_loop_p (class loop *loop, tree name, vec<gimple *> &dbg_to_reset) |
| 1397 | { |
| 1398 | imm_use_iterator it; |
| 1399 | use_operand_p use; |
| 1400 | |
| 1401 | FOR_EACH_IMM_USE_FAST (use, it, name)for ((use) = first_readonly_imm_use (&(it), (name)); !end_readonly_imm_use_p (&(it)); (void) ((use) = next_readonly_imm_use (&(it )))) |
| 1402 | { |
| 1403 | gimple *stmt = USE_STMT (use)(use)->loc.stmt; |
| 1404 | if (!flow_bb_inside_loop_p (loop, gimple_bb (stmt))) |
| 1405 | { |
| 1406 | if (!is_gimple_debug (stmt)) |
| 1407 | return true; |
| 1408 | dbg_to_reset.safe_push (stmt); |
| 1409 | } |
| 1410 | } |
| 1411 | |
| 1412 | return false; |
| 1413 | } |
| 1414 | |
| 1415 | /* Return argument for loop preheader edge in header virtual phi if any. */ |
| 1416 | |
| 1417 | static tree |
| 1418 | get_vop_from_header (class loop *loop) |
| 1419 | { |
| 1420 | for (gphi_iterator gsi = gsi_start_phis (loop->header); |
| 1421 | !gsi_end_p (gsi); gsi_next (&gsi)) |
| 1422 | { |
| 1423 | gphi *phi = gsi.phi (); |
| 1424 | if (!virtual_operand_p (gimple_phi_result (phi))) |
| 1425 | continue; |
| 1426 | return PHI_ARG_DEF_FROM_EDGE (phi, loop_preheader_edge (loop))gimple_phi_arg_def (((phi)), ((loop_preheader_edge (loop))-> dest_idx)); |
| 1427 | } |
| 1428 | return NULL_TREE(tree) nullptr; |
| 1429 | } |
| 1430 | |
| 1431 | /* Move the check of GUARD outside of LOOP. */ |
| 1432 | |
| 1433 | static void |
| 1434 | hoist_guard (class loop *loop, edge guard) |
| 1435 | { |
| 1436 | edge exit = single_exit (loop); |
| 1437 | edge preh = loop_preheader_edge (loop); |
| 1438 | basic_block pre_header = preh->src; |
| 1439 | basic_block bb; |
| 1440 | edge te, fe, e, new_edge; |
| 1441 | gimple *stmt; |
| 1442 | basic_block guard_bb = guard->src; |
| 1443 | edge not_guard; |
| 1444 | gimple_stmt_iterator gsi; |
| 1445 | int flags = 0; |
| 1446 | bool fix_dom_of_exit; |
| 1447 | gcond *cond_stmt, *new_cond_stmt; |
| 1448 | |
| 1449 | bb = get_immediate_dominator (CDI_DOMINATORS, exit->dest); |
| 1450 | fix_dom_of_exit = flow_bb_inside_loop_p (loop, bb); |
| 1451 | gsi = gsi_last_bb (guard_bb); |
| 1452 | stmt = gsi_stmt (gsi); |
| 1453 | gcc_assert (gimple_code (stmt) == GIMPLE_COND)((void)(!(gimple_code (stmt) == GIMPLE_COND) ? fancy_abort ("/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 1453, __FUNCTION__), 0 : 0)); |
| 1454 | cond_stmt = as_a <gcond *> (stmt); |
| 1455 | extract_true_false_edges_from_block (guard_bb, &te, &fe); |
| 1456 | /* Insert guard to PRE_HEADER. */ |
| 1457 | if (!empty_block_p (pre_header)) |
| 1458 | gsi = gsi_last_bb (pre_header); |
| 1459 | else |
| 1460 | gsi = gsi_start_bb (pre_header); |
| 1461 | /* Create copy of COND_STMT. */ |
| 1462 | new_cond_stmt = gimple_build_cond (gimple_cond_code (cond_stmt), |
| 1463 | gimple_cond_lhs (cond_stmt), |
| 1464 | gimple_cond_rhs (cond_stmt), |
| 1465 | NULL_TREE(tree) nullptr, NULL_TREE(tree) nullptr); |
| 1466 | gsi_insert_after (&gsi, new_cond_stmt, GSI_NEW_STMT); |
| 1467 | /* Convert COND_STMT to true/false conditional. */ |
| 1468 | if (guard == te) |
| 1469 | gimple_cond_make_false (cond_stmt); |
| 1470 | else |
| 1471 | gimple_cond_make_true (cond_stmt); |
| 1472 | update_stmt (cond_stmt); |
| 1473 | /* Create new loop pre-header. */ |
| 1474 | e = split_block (pre_header, last_stmt (pre_header)); |
| 1475 | |
| 1476 | dump_user_location_t loc = find_loop_location (loop); |
| 1477 | |
| 1478 | if (dump_enabled_p ()) |
| 1479 | { |
| 1480 | char buffer[64]; |
| 1481 | guard->probability.dump (buffer); |
| 1482 | |
| 1483 | dump_printf_loc (MSG_NOTE, loc, |
| 1484 | "Moving guard %i->%i (prob %s) to bb %i, " |
| 1485 | "new preheader is %i\n", |
| 1486 | guard->src->index, guard->dest->index, |
| 1487 | buffer, e->src->index, e->dest->index); |
| 1488 | } |
| 1489 | |
| 1490 | gcc_assert (loop_preheader_edge (loop)->src == e->dest)((void)(!(loop_preheader_edge (loop)->src == e->dest) ? fancy_abort ("/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 1490, __FUNCTION__), 0 : 0)); |
| 1491 | |
| 1492 | if (guard == fe) |
| 1493 | { |
| 1494 | e->flags = EDGE_TRUE_VALUE; |
| 1495 | flags |= EDGE_FALSE_VALUE; |
| 1496 | not_guard = te; |
| 1497 | } |
| 1498 | else |
| 1499 | { |
| 1500 | e->flags = EDGE_FALSE_VALUE; |
| 1501 | flags |= EDGE_TRUE_VALUE; |
| 1502 | not_guard = fe; |
| 1503 | } |
| 1504 | new_edge = make_edge (pre_header, exit->dest, flags); |
| 1505 | |
| 1506 | /* Determine the probability that we skip the loop. Assume that loop has |
| 1507 | same average number of iterations regardless outcome of guard. */ |
| 1508 | new_edge->probability = guard->probability; |
| 1509 | profile_count skip_count = guard->src->count.nonzero_p () |
| 1510 | ? guard->count ().apply_scale (pre_header->count, |
| 1511 | guard->src->count) |
| 1512 | : guard->count ().apply_probability (new_edge->probability); |
| 1513 | |
| 1514 | if (skip_count > e->count ()) |
| 1515 | { |
| 1516 | fprintf (dump_file, " Capping count; expect profile inconsistency\n"); |
| 1517 | skip_count = e->count (); |
| 1518 | } |
| 1519 | if (dump_enabled_p ()) |
| 1520 | { |
| 1521 | char buffer[64]; |
| 1522 | new_edge->probability.dump (buffer); |
| 1523 | |
| 1524 | dump_printf_loc (MSG_NOTE, loc, |
| 1525 | "Estimated probability of skipping loop is %s\n", |
| 1526 | buffer); |
| 1527 | } |
| 1528 | |
| 1529 | /* Update profile after the transform: |
| 1530 | |
| 1531 | First decrease count of path from newly hoisted loop guard |
| 1532 | to loop header... */ |
| 1533 | e->probability = new_edge->probability.invert (); |
| 1534 | e->dest->count = e->count (); |
| 1535 | |
| 1536 | /* ... now update profile to represent that original guard will be optimized |
| 1537 | away ... */ |
| 1538 | guard->probability = profile_probability::never (); |
| 1539 | not_guard->probability = profile_probability::always (); |
| 1540 | |
| 1541 | /* ... finally scale everything in the loop except for guarded basic blocks |
| 1542 | where profile does not change. */ |
| 1543 | basic_block *body = get_loop_body (loop); |
| 1544 | |
| 1545 | for (unsigned int i = 0; i < loop->num_nodes; i++) |
| 1546 | { |
| 1547 | basic_block bb = body[i]; |
| 1548 | if (!dominated_by_p (CDI_DOMINATORS, bb, not_guard->dest)) |
| 1549 | { |
| 1550 | if (dump_enabled_p ()) |
| 1551 | dump_printf_loc (MSG_NOTE, loc, |
| 1552 | "Scaling nonguarded BBs in loop: %i\n", |
| 1553 | bb->index); |
| 1554 | if (e->probability.initialized_p ()) |
| 1555 | scale_bbs_frequencies (&bb, 1, e->probability); |
| 1556 | } |
| 1557 | } |
| 1558 | |
| 1559 | if (fix_dom_of_exit) |
| 1560 | set_immediate_dominator (CDI_DOMINATORS, exit->dest, pre_header); |
| 1561 | /* Add NEW_ADGE argument for all phi in post-header block. */ |
| 1562 | bb = exit->dest; |
| 1563 | for (gphi_iterator gsi = gsi_start_phis (bb); |
| 1564 | !gsi_end_p (gsi); gsi_next (&gsi)) |
| 1565 | { |
| 1566 | gphi *phi = gsi.phi (); |
| 1567 | tree arg; |
| 1568 | if (virtual_operand_p (gimple_phi_result (phi))) |
| 1569 | { |
| 1570 | arg = get_vop_from_header (loop); |
| 1571 | if (arg == NULL_TREE(tree) nullptr) |
| 1572 | /* Use exit edge argument. */ |
| 1573 | arg = PHI_ARG_DEF_FROM_EDGE (phi, exit)gimple_phi_arg_def (((phi)), ((exit)->dest_idx)); |
| 1574 | add_phi_arg (phi, arg, new_edge, UNKNOWN_LOCATION((location_t) 0)); |
| 1575 | } |
| 1576 | else |
| 1577 | { |
| 1578 | /* Use exit edge argument. */ |
| 1579 | arg = PHI_ARG_DEF_FROM_EDGE (phi, exit)gimple_phi_arg_def (((phi)), ((exit)->dest_idx)); |
| 1580 | add_phi_arg (phi, arg, new_edge, UNKNOWN_LOCATION((location_t) 0)); |
| 1581 | } |
| 1582 | } |
| 1583 | |
| 1584 | if (dump_enabled_p ()) |
| 1585 | dump_printf_loc (MSG_OPTIMIZED_LOCATIONS, loc, |
| 1586 | "Guard hoisted\n"); |
| 1587 | |
| 1588 | free (body); |
| 1589 | } |
| 1590 | |
| 1591 | /* Return true if phi argument for exit edge can be used |
| 1592 | for edge around loop. */ |
| 1593 | |
| 1594 | static bool |
| 1595 | check_exit_phi (class loop *loop) |
| 1596 | { |
| 1597 | edge exit = single_exit (loop); |
| 1598 | basic_block pre_header = loop_preheader_edge (loop)->src; |
| 1599 | |
| 1600 | for (gphi_iterator gsi = gsi_start_phis (exit->dest); |
| 1601 | !gsi_end_p (gsi); gsi_next (&gsi)) |
| 1602 | { |
| 1603 | gphi *phi = gsi.phi (); |
| 1604 | tree arg; |
| 1605 | gimple *def; |
| 1606 | basic_block def_bb; |
| 1607 | if (virtual_operand_p (gimple_phi_result (phi))) |
| 1608 | continue; |
| 1609 | arg = PHI_ARG_DEF_FROM_EDGE (phi, exit)gimple_phi_arg_def (((phi)), ((exit)->dest_idx)); |
| 1610 | if (TREE_CODE (arg)((enum tree_code) (arg)->base.code) != SSA_NAME) |
| 1611 | continue; |
| 1612 | def = SSA_NAME_DEF_STMT (arg)(tree_check ((arg), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 1612, __FUNCTION__, (SSA_NAME)))->ssa_name.def_stmt; |
| 1613 | if (!def) |
| 1614 | continue; |
| 1615 | def_bb = gimple_bb (def); |
| 1616 | if (!def_bb) |
| 1617 | continue; |
| 1618 | if (!dominated_by_p (CDI_DOMINATORS, pre_header, def_bb)) |
| 1619 | /* Definition inside loop! */ |
| 1620 | return false; |
| 1621 | /* Check loop closed phi invariant. */ |
| 1622 | if (!flow_bb_inside_loop_p (def_bb->loop_father, pre_header)) |
| 1623 | return false; |
| 1624 | } |
| 1625 | return true; |
| 1626 | } |
| 1627 | |
| 1628 | /* Remove all dead cases from switches that are unswitched. */ |
| 1629 | |
| 1630 | static void |
| 1631 | clean_up_after_unswitching (int ignored_edge_flag) |
| 1632 | { |
| 1633 | basic_block bb; |
| 1634 | edge e; |
| 1635 | edge_iterator ei; |
| 1636 | bool removed_edge = false; |
| 1637 | |
| 1638 | FOR_EACH_BB_FN (bb, cfun)for (bb = ((cfun + 0))->cfg->x_entry_block_ptr->next_bb ; bb != ((cfun + 0))->cfg->x_exit_block_ptr; bb = bb-> next_bb) |
| 1639 | { |
| 1640 | gswitch *stmt= safe_dyn_cast <gswitch *> (last_stmt (bb)); |
| 1641 | if (stmt && !CONSTANT_CLASS_P (gimple_switch_index (stmt))(tree_code_type_tmpl <0>::tree_code_type[(int) (((enum tree_code ) (gimple_switch_index (stmt))->base.code))] == tcc_constant )) |
| 1642 | { |
| 1643 | unsigned nlabels = gimple_switch_num_labels (stmt); |
| 1644 | unsigned index = 1; |
| 1645 | tree lab = gimple_switch_default_label (stmt); |
| 1646 | edge default_e = find_edge (gimple_bb (stmt), |
| 1647 | label_to_block (cfun(cfun + 0), CASE_LABEL (lab)(*((const_cast<tree*> (tree_operand_check (((tree_check ((lab), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 1647, __FUNCTION__, (CASE_LABEL_EXPR)))), (2), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 1647, __FUNCTION__))))))); |
| 1648 | for (unsigned i = 1; i < nlabels; ++i) |
| 1649 | { |
| 1650 | tree lab = gimple_switch_label (stmt, i); |
| 1651 | basic_block dest = label_to_block (cfun(cfun + 0), CASE_LABEL (lab)(*((const_cast<tree*> (tree_operand_check (((tree_check ((lab), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 1651, __FUNCTION__, (CASE_LABEL_EXPR)))), (2), "/buildworker/marxinbox-gcc-clang-static-analyzer/build/gcc/tree-ssa-loop-unswitch.cc" , 1651, __FUNCTION__)))))); |
| 1652 | edge e = find_edge (gimple_bb (stmt), dest); |
| 1653 | if (e == NULLnullptr) |
| 1654 | ; /* The edge is already removed. */ |
| 1655 | else if (e->flags & ignored_edge_flag) |
| 1656 | { |
| 1657 | /* We may not remove the default label so we also have |
| 1658 | to preserve its edge. But we can remove the |
| 1659 | non-default CASE sharing the edge. */ |
| 1660 | if (e != default_e) |
| 1661 | { |
| 1662 | remove_edge (e); |
| 1663 | removed_edge = true; |
| 1664 | } |
| 1665 | } |
| 1666 | else |
| 1667 | { |
| 1668 | gimple_switch_set_label (stmt, index, lab); |
| 1669 | ++index; |
| 1670 | } |
| 1671 | } |
| 1672 | |
| 1673 | if (index != nlabels) |
| 1674 | gimple_switch_set_num_labels (stmt, index); |
| 1675 | } |
| 1676 | |
| 1677 | /* Clean up the ignored_edge_flag from edges. */ |
| 1678 | FOR_EACH_EDGE (e, ei, bb->succs)for ((ei) = ei_start_1 (&((bb->succs))); ei_cond ((ei) , &(e)); ei_next (&(ei))) |
| 1679 | e->flags &= ~ignored_edge_flag; |
| 1680 | } |
| 1681 | |
| 1682 | /* If we removed an edge we possibly have to recompute dominators. */ |
| 1683 | if (removed_edge) |
| 1684 | free_dominance_info (CDI_DOMINATORS); |
| 1685 | } |
| 1686 | |
| 1687 | /* Loop unswitching pass. */ |
| 1688 | |
| 1689 | namespace { |
| 1690 | |
| 1691 | const pass_data pass_data_tree_unswitch = |
| 1692 | { |
| 1693 | GIMPLE_PASS, /* type */ |
| 1694 | "unswitch", /* name */ |
| 1695 | OPTGROUP_LOOP, /* optinfo_flags */ |
| 1696 | TV_TREE_LOOP_UNSWITCH, /* tv_id */ |
| 1697 | PROP_cfg(1 << 3), /* properties_required */ |
| 1698 | 0, /* properties_provided */ |
| 1699 | 0, /* properties_destroyed */ |
| 1700 | 0, /* todo_flags_start */ |
| 1701 | 0, /* todo_flags_finish */ |
| 1702 | }; |
| 1703 | |
| 1704 | class pass_tree_unswitch : public gimple_opt_pass |
| 1705 | { |
| 1706 | public: |
| 1707 | pass_tree_unswitch (gcc::context *ctxt) |
| 1708 | : gimple_opt_pass (pass_data_tree_unswitch, ctxt) |
| 1709 | {} |
| 1710 | |
| 1711 | /* opt_pass methods: */ |
| 1712 | bool gate (function *) final override { return flag_unswitch_loopsglobal_options.x_flag_unswitch_loops != 0; } |
| 1713 | unsigned int execute (function *) final override; |
| 1714 | |
| 1715 | }; // class pass_tree_unswitch |
| 1716 | |
| 1717 | unsigned int |
| 1718 | pass_tree_unswitch::execute (function *fun) |
| 1719 | { |
| 1720 | if (number_of_loops (fun) <= 1) |
| 1721 | return 0; |
| 1722 | |
| 1723 | return tree_ssa_unswitch_loops (fun); |
| 1724 | } |
| 1725 | |
| 1726 | } // anon namespace |
| 1727 | |
| 1728 | gimple_opt_pass * |
| 1729 | make_pass_tree_unswitch (gcc::context *ctxt) |
| 1730 | { |
| 1731 | return new pass_tree_unswitch (ctxt); |
| 1732 | } |
| 1733 | |
| 1734 |