Mercurial > hg > CbC > CbC_gcc
annotate gcc/tree-ssa-propagate.c @ 123:ab229f40eab2
fix inline_call
| author | mir3636 |
|---|---|
| date | Fri, 30 Mar 2018 22:58:55 +0900 |
| parents | 04ced10e8804 |
| children | 84e7813d76e9 |
| rev | line source |
|---|---|
| 0 | 1 /* Generic SSA value propagation engine. |
| 111 | 2 Copyright (C) 2004-2017 Free Software Foundation, Inc. |
| 0 | 3 Contributed by Diego Novillo <dnovillo@redhat.com> |
| 4 | |
| 5 This file is part of GCC. | |
| 6 | |
| 7 GCC is free software; you can redistribute it and/or modify it | |
| 8 under the terms of the GNU General Public License as published by the | |
| 9 Free Software Foundation; either version 3, or (at your option) any | |
| 10 later version. | |
| 11 | |
| 12 GCC is distributed in the hope that it will be useful, but WITHOUT | |
| 13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 15 for more details. | |
| 16 | |
| 17 You should have received a copy of the GNU General Public License | |
| 18 along with GCC; see the file COPYING3. If not see | |
| 19 <http://www.gnu.org/licenses/>. */ | |
| 20 | |
| 21 #include "config.h" | |
| 22 #include "system.h" | |
| 23 #include "coretypes.h" | |
| 111 | 24 #include "backend.h" |
| 0 | 25 #include "tree.h" |
| 111 | 26 #include "gimple.h" |
| 27 #include "ssa.h" | |
|
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28 #include "gimple-pretty-print.h" |
| 111 | 29 #include "dumpfile.h" |
| 30 #include "gimple-fold.h" | |
| 31 #include "tree-eh.h" | |
| 32 #include "gimplify.h" | |
| 33 #include "gimple-iterator.h" | |
| 34 #include "tree-cfg.h" | |
| 35 #include "tree-ssa.h" | |
| 0 | 36 #include "tree-ssa-propagate.h" |
| 111 | 37 #include "domwalk.h" |
| 38 #include "cfgloop.h" | |
| 39 #include "tree-cfgcleanup.h" | |
| 40 #include "cfganal.h" | |
| 0 | 41 |
| 42 /* This file implements a generic value propagation engine based on | |
| 43 the same propagation used by the SSA-CCP algorithm [1]. | |
| 44 | |
| 45 Propagation is performed by simulating the execution of every | |
| 46 statement that produces the value being propagated. Simulation | |
| 47 proceeds as follows: | |
| 48 | |
| 49 1- Initially, all edges of the CFG are marked not executable and | |
| 50 the CFG worklist is seeded with all the statements in the entry | |
| 51 basic block (block 0). | |
| 52 | |
| 53 2- Every statement S is simulated with a call to the call-back | |
| 54 function SSA_PROP_VISIT_STMT. This evaluation may produce 3 | |
| 55 results: | |
| 56 | |
| 57 SSA_PROP_NOT_INTERESTING: Statement S produces nothing of | |
| 58 interest and does not affect any of the work lists. | |
| 111 | 59 The statement may be simulated again if any of its input |
| 60 operands change in future iterations of the simulator. | |
| 0 | 61 |
| 62 SSA_PROP_VARYING: The value produced by S cannot be determined | |
| 63 at compile time. Further simulation of S is not required. | |
| 64 If S is a conditional jump, all the outgoing edges for the | |
| 65 block are considered executable and added to the work | |
| 66 list. | |
| 67 | |
| 68 SSA_PROP_INTERESTING: S produces a value that can be computed | |
| 69 at compile time. Its result can be propagated into the | |
| 70 statements that feed from S. Furthermore, if S is a | |
| 71 conditional jump, only the edge known to be taken is added | |
| 72 to the work list. Edges that are known not to execute are | |
| 73 never simulated. | |
| 74 | |
| 75 3- PHI nodes are simulated with a call to SSA_PROP_VISIT_PHI. The | |
| 76 return value from SSA_PROP_VISIT_PHI has the same semantics as | |
| 77 described in #2. | |
| 78 | |
| 79 4- Three work lists are kept. Statements are only added to these | |
| 80 lists if they produce one of SSA_PROP_INTERESTING or | |
| 81 SSA_PROP_VARYING. | |
| 82 | |
| 83 CFG_BLOCKS contains the list of blocks to be simulated. | |
| 84 Blocks are added to this list if their incoming edges are | |
| 85 found executable. | |
| 86 | |
| 111 | 87 SSA_EDGE_WORKLIST contains the list of statements that we |
| 88 need to revisit. | |
| 0 | 89 |
| 90 5- Simulation terminates when all three work lists are drained. | |
| 91 | |
| 92 Before calling ssa_propagate, it is important to clear | |
| 93 prop_simulate_again_p for all the statements in the program that | |
| 94 should be simulated. This initialization allows an implementation | |
| 95 to specify which statements should never be simulated. | |
| 96 | |
| 97 It is also important to compute def-use information before calling | |
| 98 ssa_propagate. | |
| 99 | |
| 100 References: | |
| 101 | |
| 102 [1] Constant propagation with conditional branches, | |
| 103 Wegman and Zadeck, ACM TOPLAS 13(2):181-210. | |
| 104 | |
| 105 [2] Building an Optimizing Compiler, | |
| 106 Robert Morgan, Butterworth-Heinemann, 1998, Section 8.9. | |
| 107 | |
| 108 [3] Advanced Compiler Design and Implementation, | |
| 109 Steven Muchnick, Morgan Kaufmann, 1997, Section 12.6 */ | |
| 110 | |
| 111 /* Function pointers used to parameterize the propagation engine. */ | |
| 112 static ssa_prop_visit_stmt_fn ssa_prop_visit_stmt; | |
| 113 static ssa_prop_visit_phi_fn ssa_prop_visit_phi; | |
| 114 | |
| 111 | 115 /* Worklist of control flow edge destinations. This contains |
| 116 the CFG order number of the blocks so we can iterate in CFG | |
| 117 order by visiting in bit-order. */ | |
| 118 static bitmap cfg_blocks; | |
| 119 static int *bb_to_cfg_order; | |
| 120 static int *cfg_order_to_bb; | |
| 0 | 121 |
| 122 /* Worklist of SSA edges which will need reexamination as their | |
| 123 definition has changed. SSA edges are def-use edges in the SSA | |
| 124 web. For each D-U edge, we store the target statement or PHI node | |
| 111 | 125 UID in a bitmap. UIDs order stmts in execution order. */ |
| 126 static bitmap ssa_edge_worklist; | |
| 127 static vec<gimple *> uid_to_stmt; | |
| 0 | 128 |
| 129 /* Return true if the block worklist empty. */ | |
| 130 | |
| 131 static inline bool | |
| 132 cfg_blocks_empty_p (void) | |
| 133 { | |
| 111 | 134 return bitmap_empty_p (cfg_blocks); |
| 0 | 135 } |
| 136 | |
| 137 | |
| 111 | 138 /* Add a basic block to the worklist. The block must not be the ENTRY |
| 139 or EXIT block. */ | |
| 0 | 140 |
|
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141 static void |
| 0 | 142 cfg_blocks_add (basic_block bb) |
| 143 { | |
| 111 | 144 gcc_assert (bb != ENTRY_BLOCK_PTR_FOR_FN (cfun) |
| 145 && bb != EXIT_BLOCK_PTR_FOR_FN (cfun)); | |
| 146 bitmap_set_bit (cfg_blocks, bb_to_cfg_order[bb->index]); | |
| 0 | 147 } |
| 148 | |
| 149 | |
| 150 /* Remove a block from the worklist. */ | |
| 151 | |
| 152 static basic_block | |
| 153 cfg_blocks_get (void) | |
| 154 { | |
| 155 gcc_assert (!cfg_blocks_empty_p ()); | |
| 111 | 156 int order_index = bitmap_first_set_bit (cfg_blocks); |
| 157 bitmap_clear_bit (cfg_blocks, order_index); | |
| 158 return BASIC_BLOCK_FOR_FN (cfun, cfg_order_to_bb [order_index]); | |
| 0 | 159 } |
| 160 | |
| 161 | |
| 162 /* We have just defined a new value for VAR. If IS_VARYING is true, | |
| 163 add all immediate uses of VAR to VARYING_SSA_EDGES, otherwise add | |
| 164 them to INTERESTING_SSA_EDGES. */ | |
| 165 | |
| 166 static void | |
| 111 | 167 add_ssa_edge (tree var) |
| 0 | 168 { |
| 169 imm_use_iterator iter; | |
| 170 use_operand_p use_p; | |
| 171 | |
| 172 FOR_EACH_IMM_USE_FAST (use_p, iter, var) | |
| 173 { | |
| 111 | 174 gimple *use_stmt = USE_STMT (use_p); |
| 175 | |
| 176 /* If we did not yet simulate the block wait for this to happen | |
| 177 and do not add the stmt to the SSA edge worklist. */ | |
| 178 if (! (gimple_bb (use_stmt)->flags & BB_VISITED)) | |
| 179 continue; | |
| 0 | 180 |
| 181 if (prop_simulate_again_p (use_stmt) | |
| 111 | 182 && bitmap_set_bit (ssa_edge_worklist, gimple_uid (use_stmt))) |
| 0 | 183 { |
| 111 | 184 uid_to_stmt[gimple_uid (use_stmt)] = use_stmt; |
| 185 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 186 { | |
| 187 fprintf (dump_file, "ssa_edge_worklist: adding SSA use in "); | |
| 188 print_gimple_stmt (dump_file, use_stmt, 0, TDF_SLIM); | |
| 189 } | |
| 0 | 190 } |
| 191 } | |
| 192 } | |
| 193 | |
| 194 | |
| 195 /* Add edge E to the control flow worklist. */ | |
| 196 | |
| 197 static void | |
| 198 add_control_edge (edge e) | |
| 199 { | |
| 200 basic_block bb = e->dest; | |
| 111 | 201 if (bb == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
| 0 | 202 return; |
| 203 | |
| 204 /* If the edge had already been executed, skip it. */ | |
| 205 if (e->flags & EDGE_EXECUTABLE) | |
| 206 return; | |
| 207 | |
| 208 e->flags |= EDGE_EXECUTABLE; | |
| 209 | |
| 210 cfg_blocks_add (bb); | |
| 211 | |
| 212 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 111 | 213 fprintf (dump_file, "Adding destination of edge (%d -> %d) to worklist\n", |
| 0 | 214 e->src->index, e->dest->index); |
| 215 } | |
| 216 | |
| 217 | |
| 218 /* Simulate the execution of STMT and update the work lists accordingly. */ | |
| 219 | |
| 220 static void | |
| 111 | 221 simulate_stmt (gimple *stmt) |
| 0 | 222 { |
| 223 enum ssa_prop_result val = SSA_PROP_NOT_INTERESTING; | |
| 224 edge taken_edge = NULL; | |
| 225 tree output_name = NULL_TREE; | |
| 226 | |
| 111 | 227 /* Pull the stmt off the SSA edge worklist. */ |
| 228 bitmap_clear_bit (ssa_edge_worklist, gimple_uid (stmt)); | |
| 229 | |
| 0 | 230 /* Don't bother visiting statements that are already |
| 231 considered varying by the propagator. */ | |
| 232 if (!prop_simulate_again_p (stmt)) | |
| 233 return; | |
| 234 | |
| 235 if (gimple_code (stmt) == GIMPLE_PHI) | |
| 236 { | |
| 111 | 237 val = ssa_prop_visit_phi (as_a <gphi *> (stmt)); |
| 0 | 238 output_name = gimple_phi_result (stmt); |
| 239 } | |
| 240 else | |
| 241 val = ssa_prop_visit_stmt (stmt, &taken_edge, &output_name); | |
| 242 | |
| 243 if (val == SSA_PROP_VARYING) | |
| 244 { | |
| 245 prop_set_simulate_again (stmt, false); | |
| 246 | |
| 247 /* If the statement produced a new varying value, add the SSA | |
| 248 edges coming out of OUTPUT_NAME. */ | |
| 249 if (output_name) | |
| 111 | 250 add_ssa_edge (output_name); |
| 0 | 251 |
| 252 /* If STMT transfers control out of its basic block, add | |
| 253 all outgoing edges to the work list. */ | |
| 254 if (stmt_ends_bb_p (stmt)) | |
| 255 { | |
| 256 edge e; | |
| 257 edge_iterator ei; | |
| 258 basic_block bb = gimple_bb (stmt); | |
| 259 FOR_EACH_EDGE (e, ei, bb->succs) | |
| 260 add_control_edge (e); | |
| 261 } | |
| 111 | 262 return; |
| 0 | 263 } |
| 264 else if (val == SSA_PROP_INTERESTING) | |
| 265 { | |
| 266 /* If the statement produced new value, add the SSA edges coming | |
| 267 out of OUTPUT_NAME. */ | |
| 268 if (output_name) | |
| 111 | 269 add_ssa_edge (output_name); |
| 0 | 270 |
| 271 /* If we know which edge is going to be taken out of this block, | |
| 272 add it to the CFG work list. */ | |
| 273 if (taken_edge) | |
| 274 add_control_edge (taken_edge); | |
| 275 } | |
| 111 | 276 |
| 277 /* If there are no SSA uses on the stmt whose defs are simulated | |
| 278 again then this stmt will be never visited again. */ | |
| 279 bool has_simulate_again_uses = false; | |
| 280 use_operand_p use_p; | |
| 281 ssa_op_iter iter; | |
| 282 if (gimple_code (stmt) == GIMPLE_PHI) | |
| 283 { | |
| 284 edge_iterator ei; | |
| 285 edge e; | |
| 286 tree arg; | |
| 287 FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->preds) | |
| 288 if (!(e->flags & EDGE_EXECUTABLE) | |
| 289 || ((arg = PHI_ARG_DEF_FROM_EDGE (stmt, e)) | |
| 290 && TREE_CODE (arg) == SSA_NAME | |
| 291 && !SSA_NAME_IS_DEFAULT_DEF (arg) | |
| 292 && prop_simulate_again_p (SSA_NAME_DEF_STMT (arg)))) | |
| 293 { | |
| 294 has_simulate_again_uses = true; | |
| 295 break; | |
| 296 } | |
| 297 } | |
| 298 else | |
| 299 FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) | |
| 300 { | |
| 301 gimple *def_stmt = SSA_NAME_DEF_STMT (USE_FROM_PTR (use_p)); | |
| 302 if (!gimple_nop_p (def_stmt) | |
| 303 && prop_simulate_again_p (def_stmt)) | |
| 304 { | |
| 305 has_simulate_again_uses = true; | |
| 306 break; | |
| 307 } | |
| 308 } | |
| 309 if (!has_simulate_again_uses) | |
| 310 { | |
| 311 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 312 fprintf (dump_file, "marking stmt to be not simulated again\n"); | |
| 313 prop_set_simulate_again (stmt, false); | |
| 314 } | |
| 0 | 315 } |
| 316 | |
| 317 /* Process an SSA edge worklist. WORKLIST is the SSA edge worklist to | |
| 318 drain. This pops statements off the given WORKLIST and processes | |
| 111 | 319 them until one statement was simulated or there are no more statements |
| 320 on WORKLIST. We take a pointer to WORKLIST because it may be reallocated | |
| 321 when an SSA edge is added to it in simulate_stmt. Return true if a stmt | |
| 322 was simulated. */ | |
| 0 | 323 |
| 324 static void | |
| 111 | 325 process_ssa_edge_worklist () |
| 0 | 326 { |
| 111 | 327 /* Process the next entry from the worklist. */ |
| 328 unsigned stmt_uid = bitmap_first_set_bit (ssa_edge_worklist); | |
| 329 bitmap_clear_bit (ssa_edge_worklist, stmt_uid); | |
| 330 gimple *stmt = uid_to_stmt[stmt_uid]; | |
| 0 | 331 |
| 111 | 332 /* We should not have stmts in not yet simulated BBs on the worklist. */ |
| 333 gcc_assert (gimple_bb (stmt)->flags & BB_VISITED); | |
| 0 | 334 |
| 111 | 335 if (dump_file && (dump_flags & TDF_DETAILS)) |
| 336 { | |
| 337 fprintf (dump_file, "\nSimulating statement: "); | |
| 338 print_gimple_stmt (dump_file, stmt, 0, dump_flags); | |
| 339 } | |
| 0 | 340 |
| 111 | 341 simulate_stmt (stmt); |
| 0 | 342 } |
| 343 | |
| 344 | |
| 345 /* Simulate the execution of BLOCK. Evaluate the statement associated | |
| 346 with each variable reference inside the block. */ | |
| 347 | |
| 348 static void | |
| 349 simulate_block (basic_block block) | |
| 350 { | |
| 351 gimple_stmt_iterator gsi; | |
| 352 | |
| 353 /* There is nothing to do for the exit block. */ | |
| 111 | 354 if (block == EXIT_BLOCK_PTR_FOR_FN (cfun)) |
| 0 | 355 return; |
| 356 | |
| 357 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 358 fprintf (dump_file, "\nSimulating block %d\n", block->index); | |
| 359 | |
| 360 /* Always simulate PHI nodes, even if we have simulated this block | |
| 361 before. */ | |
| 362 for (gsi = gsi_start_phis (block); !gsi_end_p (gsi); gsi_next (&gsi)) | |
| 363 simulate_stmt (gsi_stmt (gsi)); | |
| 364 | |
| 365 /* If this is the first time we've simulated this block, then we | |
| 366 must simulate each of its statements. */ | |
| 111 | 367 if (! (block->flags & BB_VISITED)) |
| 0 | 368 { |
| 369 gimple_stmt_iterator j; | |
| 370 unsigned int normal_edge_count; | |
| 371 edge e, normal_edge; | |
| 372 edge_iterator ei; | |
| 373 | |
| 374 for (j = gsi_start_bb (block); !gsi_end_p (j); gsi_next (&j)) | |
| 111 | 375 simulate_stmt (gsi_stmt (j)); |
| 0 | 376 |
| 111 | 377 /* Note that we have simulated this block. */ |
| 378 block->flags |= BB_VISITED; | |
| 0 | 379 |
|
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380 /* We can not predict when abnormal and EH edges will be executed, so |
| 0 | 381 once a block is considered executable, we consider any |
| 382 outgoing abnormal edges as executable. | |
| 383 | |
|
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384 TODO: This is not exactly true. Simplifying statement might |
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385 prove it non-throwing and also computed goto can be handled |
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386 when destination is known. |
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387 |
| 0 | 388 At the same time, if this block has only one successor that is |
| 389 reached by non-abnormal edges, then add that successor to the | |
| 390 worklist. */ | |
| 391 normal_edge_count = 0; | |
| 392 normal_edge = NULL; | |
| 393 FOR_EACH_EDGE (e, ei, block->succs) | |
| 394 { | |
|
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395 if (e->flags & (EDGE_ABNORMAL | EDGE_EH)) |
| 0 | 396 add_control_edge (e); |
| 397 else | |
| 398 { | |
| 399 normal_edge_count++; | |
| 400 normal_edge = e; | |
| 401 } | |
| 402 } | |
| 403 | |
| 404 if (normal_edge_count == 1) | |
| 405 add_control_edge (normal_edge); | |
| 406 } | |
| 407 } | |
| 408 | |
| 409 | |
| 410 /* Initialize local data structures and work lists. */ | |
| 411 | |
| 412 static void | |
| 413 ssa_prop_init (void) | |
| 414 { | |
| 415 edge e; | |
| 416 edge_iterator ei; | |
| 417 basic_block bb; | |
| 418 | |
| 419 /* Worklists of SSA edges. */ | |
| 111 | 420 ssa_edge_worklist = BITMAP_ALLOC (NULL); |
| 0 | 421 |
| 111 | 422 /* Worklist of basic-blocks. */ |
| 423 bb_to_cfg_order = XNEWVEC (int, last_basic_block_for_fn (cfun) + 1); | |
| 424 cfg_order_to_bb = XNEWVEC (int, n_basic_blocks_for_fn (cfun)); | |
| 425 int n = pre_and_rev_post_order_compute_fn (cfun, NULL, | |
| 426 cfg_order_to_bb, false); | |
| 427 for (int i = 0; i < n; ++i) | |
| 428 bb_to_cfg_order[cfg_order_to_bb[i]] = i; | |
| 429 cfg_blocks = BITMAP_ALLOC (NULL); | |
| 0 | 430 |
| 431 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 432 dump_immediate_uses (dump_file); | |
| 433 | |
| 434 /* Initially assume that every edge in the CFG is not executable. | |
| 111 | 435 (including the edges coming out of the entry block). Mark blocks |
| 436 as not visited, blocks not yet visited will have all their statements | |
| 437 simulated once an incoming edge gets executable. */ | |
| 438 set_gimple_stmt_max_uid (cfun, 0); | |
| 439 for (int i = 0; i < n; ++i) | |
| 0 | 440 { |
| 441 gimple_stmt_iterator si; | |
| 111 | 442 bb = BASIC_BLOCK_FOR_FN (cfun, cfg_order_to_bb[i]); |
| 443 | |
| 444 for (si = gsi_start_phis (bb); !gsi_end_p (si); gsi_next (&si)) | |
| 445 { | |
| 446 gimple *stmt = gsi_stmt (si); | |
| 447 gimple_set_uid (stmt, inc_gimple_stmt_max_uid (cfun)); | |
| 448 } | |
| 0 | 449 |
| 450 for (si = gsi_start_bb (bb); !gsi_end_p (si); gsi_next (&si)) | |
| 111 | 451 { |
| 452 gimple *stmt = gsi_stmt (si); | |
| 453 gimple_set_uid (stmt, inc_gimple_stmt_max_uid (cfun)); | |
| 454 } | |
|
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455 |
| 111 | 456 bb->flags &= ~BB_VISITED; |
| 0 | 457 FOR_EACH_EDGE (e, ei, bb->succs) |
| 458 e->flags &= ~EDGE_EXECUTABLE; | |
| 459 } | |
| 111 | 460 uid_to_stmt.safe_grow (gimple_stmt_max_uid (cfun)); |
| 0 | 461 |
| 462 /* Seed the algorithm by adding the successors of the entry block to the | |
| 463 edge worklist. */ | |
| 111 | 464 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR_FOR_FN (cfun)->succs) |
| 465 { | |
| 466 e->flags &= ~EDGE_EXECUTABLE; | |
| 467 add_control_edge (e); | |
| 468 } | |
| 0 | 469 } |
| 470 | |
| 471 | |
| 472 /* Free allocated storage. */ | |
| 473 | |
| 474 static void | |
| 475 ssa_prop_fini (void) | |
| 476 { | |
| 111 | 477 BITMAP_FREE (cfg_blocks); |
| 478 free (bb_to_cfg_order); | |
| 479 free (cfg_order_to_bb); | |
| 480 BITMAP_FREE (ssa_edge_worklist); | |
| 481 uid_to_stmt.release (); | |
| 0 | 482 } |
| 483 | |
| 484 | |
| 485 /* Return true if EXPR is an acceptable right-hand-side for a | |
| 486 GIMPLE assignment. We validate the entire tree, not just | |
| 487 the root node, thus catching expressions that embed complex | |
| 488 operands that are not permitted in GIMPLE. This function | |
| 489 is needed because the folding routines in fold-const.c | |
| 490 may return such expressions in some cases, e.g., an array | |
| 491 access with an embedded index addition. It may make more | |
| 492 sense to have folding routines that are sensitive to the | |
| 493 constraints on GIMPLE operands, rather than abandoning any | |
| 494 any attempt to fold if the usual folding turns out to be too | |
| 495 aggressive. */ | |
| 496 | |
| 497 bool | |
| 498 valid_gimple_rhs_p (tree expr) | |
| 499 { | |
| 500 enum tree_code code = TREE_CODE (expr); | |
| 501 | |
| 502 switch (TREE_CODE_CLASS (code)) | |
| 503 { | |
| 504 case tcc_declaration: | |
| 505 if (!is_gimple_variable (expr)) | |
| 506 return false; | |
| 507 break; | |
| 508 | |
| 509 case tcc_constant: | |
| 510 /* All constants are ok. */ | |
| 511 break; | |
| 512 | |
| 111 | 513 case tcc_comparison: |
| 514 /* GENERIC allows comparisons with non-boolean types, reject | |
| 515 those for GIMPLE. Let vector-typed comparisons pass - rules | |
| 516 for GENERIC and GIMPLE are the same here. */ | |
| 517 if (!(INTEGRAL_TYPE_P (TREE_TYPE (expr)) | |
| 518 && (TREE_CODE (TREE_TYPE (expr)) == BOOLEAN_TYPE | |
| 519 || TYPE_PRECISION (TREE_TYPE (expr)) == 1)) | |
| 520 && ! VECTOR_TYPE_P (TREE_TYPE (expr))) | |
| 521 return false; | |
| 522 | |
| 523 /* Fallthru. */ | |
| 0 | 524 case tcc_binary: |
| 525 if (!is_gimple_val (TREE_OPERAND (expr, 0)) | |
| 526 || !is_gimple_val (TREE_OPERAND (expr, 1))) | |
| 527 return false; | |
| 528 break; | |
| 529 | |
| 530 case tcc_unary: | |
| 531 if (!is_gimple_val (TREE_OPERAND (expr, 0))) | |
| 532 return false; | |
| 533 break; | |
| 534 | |
| 535 case tcc_expression: | |
| 536 switch (code) | |
| 537 { | |
| 538 case ADDR_EXPR: | |
| 539 { | |
| 540 tree t; | |
| 541 if (is_gimple_min_invariant (expr)) | |
| 542 return true; | |
| 543 t = TREE_OPERAND (expr, 0); | |
| 544 while (handled_component_p (t)) | |
| 545 { | |
| 546 /* ??? More checks needed, see the GIMPLE verifier. */ | |
| 547 if ((TREE_CODE (t) == ARRAY_REF | |
| 548 || TREE_CODE (t) == ARRAY_RANGE_REF) | |
| 549 && !is_gimple_val (TREE_OPERAND (t, 1))) | |
| 550 return false; | |
| 551 t = TREE_OPERAND (t, 0); | |
| 552 } | |
| 553 if (!is_gimple_id (t)) | |
| 554 return false; | |
| 555 } | |
| 556 break; | |
| 557 | |
| 558 default: | |
| 111 | 559 if (get_gimple_rhs_class (code) == GIMPLE_TERNARY_RHS) |
| 560 { | |
| 561 if (((code == VEC_COND_EXPR || code == COND_EXPR) | |
| 562 ? !is_gimple_condexpr (TREE_OPERAND (expr, 0)) | |
| 563 : !is_gimple_val (TREE_OPERAND (expr, 0))) | |
| 564 || !is_gimple_val (TREE_OPERAND (expr, 1)) | |
| 565 || !is_gimple_val (TREE_OPERAND (expr, 2))) | |
| 566 return false; | |
| 567 break; | |
| 568 } | |
| 0 | 569 return false; |
| 570 } | |
| 571 break; | |
| 572 | |
| 573 case tcc_vl_exp: | |
| 574 return false; | |
| 575 | |
| 576 case tcc_exceptional: | |
| 111 | 577 if (code == CONSTRUCTOR) |
| 578 { | |
| 579 unsigned i; | |
| 580 tree elt; | |
| 581 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (expr), i, elt) | |
| 582 if (!is_gimple_val (elt)) | |
| 583 return false; | |
| 584 return true; | |
| 585 } | |
| 0 | 586 if (code != SSA_NAME) |
| 587 return false; | |
| 588 break; | |
| 589 | |
| 111 | 590 case tcc_reference: |
| 591 if (code == BIT_FIELD_REF) | |
| 592 return is_gimple_val (TREE_OPERAND (expr, 0)); | |
| 593 return false; | |
| 594 | |
| 0 | 595 default: |
| 596 return false; | |
| 597 } | |
| 598 | |
| 599 return true; | |
| 600 } | |
| 601 | |
| 602 | |
| 603 /* Return true if EXPR is a CALL_EXPR suitable for representation | |
| 604 as a single GIMPLE_CALL statement. If the arguments require | |
| 605 further gimplification, return false. */ | |
| 606 | |
|
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607 static bool |
| 0 | 608 valid_gimple_call_p (tree expr) |
| 609 { | |
| 610 unsigned i, nargs; | |
| 611 | |
| 612 if (TREE_CODE (expr) != CALL_EXPR) | |
| 613 return false; | |
| 614 | |
| 615 nargs = call_expr_nargs (expr); | |
| 616 for (i = 0; i < nargs; i++) | |
|
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617 { |
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618 tree arg = CALL_EXPR_ARG (expr, i); |
| 111 | 619 if (is_gimple_reg_type (TREE_TYPE (arg))) |
|
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620 { |
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621 if (!is_gimple_val (arg)) |
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622 return false; |
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623 } |
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624 else |
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625 if (!is_gimple_lvalue (arg)) |
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626 return false; |
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627 } |
| 0 | 628 |
| 629 return true; | |
| 630 } | |
| 631 | |
| 632 | |
| 633 /* Make SSA names defined by OLD_STMT point to NEW_STMT | |
| 634 as their defining statement. */ | |
| 635 | |
| 636 void | |
| 111 | 637 move_ssa_defining_stmt_for_defs (gimple *new_stmt, gimple *old_stmt) |
| 0 | 638 { |
| 639 tree var; | |
| 640 ssa_op_iter iter; | |
| 641 | |
| 642 if (gimple_in_ssa_p (cfun)) | |
| 643 { | |
| 644 /* Make defined SSA_NAMEs point to the new | |
| 645 statement as their definition. */ | |
| 646 FOR_EACH_SSA_TREE_OPERAND (var, old_stmt, iter, SSA_OP_ALL_DEFS) | |
| 647 { | |
| 648 if (TREE_CODE (var) == SSA_NAME) | |
| 649 SSA_NAME_DEF_STMT (var) = new_stmt; | |
| 650 } | |
| 651 } | |
| 652 } | |
| 653 | |
| 111 | 654 /* Helper function for update_gimple_call and update_call_from_tree. |
| 655 A GIMPLE_CALL STMT is being replaced with GIMPLE_CALL NEW_STMT. */ | |
| 656 | |
| 657 static void | |
| 658 finish_update_gimple_call (gimple_stmt_iterator *si_p, gimple *new_stmt, | |
| 659 gimple *stmt) | |
| 660 { | |
| 661 gimple_call_set_lhs (new_stmt, gimple_call_lhs (stmt)); | |
| 662 move_ssa_defining_stmt_for_defs (new_stmt, stmt); | |
| 663 gimple_set_vuse (new_stmt, gimple_vuse (stmt)); | |
| 664 gimple_set_vdef (new_stmt, gimple_vdef (stmt)); | |
| 665 gimple_set_location (new_stmt, gimple_location (stmt)); | |
| 666 if (gimple_block (new_stmt) == NULL_TREE) | |
| 667 gimple_set_block (new_stmt, gimple_block (stmt)); | |
| 668 gsi_replace (si_p, new_stmt, false); | |
| 669 } | |
| 670 | |
| 671 /* Update a GIMPLE_CALL statement at iterator *SI_P to call to FN | |
| 672 with number of arguments NARGS, where the arguments in GIMPLE form | |
| 673 follow NARGS argument. */ | |
| 674 | |
| 675 bool | |
| 676 update_gimple_call (gimple_stmt_iterator *si_p, tree fn, int nargs, ...) | |
| 677 { | |
| 678 va_list ap; | |
| 679 gcall *new_stmt, *stmt = as_a <gcall *> (gsi_stmt (*si_p)); | |
| 680 | |
| 681 gcc_assert (is_gimple_call (stmt)); | |
| 682 va_start (ap, nargs); | |
| 683 new_stmt = gimple_build_call_valist (fn, nargs, ap); | |
| 684 finish_update_gimple_call (si_p, new_stmt, stmt); | |
| 685 va_end (ap); | |
| 686 return true; | |
| 687 } | |
| 0 | 688 |
| 689 /* Update a GIMPLE_CALL statement at iterator *SI_P to reflect the | |
| 690 value of EXPR, which is expected to be the result of folding the | |
| 691 call. This can only be done if EXPR is a CALL_EXPR with valid | |
| 692 GIMPLE operands as arguments, or if it is a suitable RHS expression | |
| 693 for a GIMPLE_ASSIGN. More complex expressions will require | |
| 111 | 694 gimplification, which will introduce additional statements. In this |
| 0 | 695 event, no update is performed, and the function returns false. |
| 696 Note that we cannot mutate a GIMPLE_CALL in-place, so we always | |
| 697 replace the statement at *SI_P with an entirely new statement. | |
| 698 The new statement need not be a call, e.g., if the original call | |
| 699 folded to a constant. */ | |
| 700 | |
| 701 bool | |
| 702 update_call_from_tree (gimple_stmt_iterator *si_p, tree expr) | |
| 703 { | |
| 111 | 704 gimple *stmt = gsi_stmt (*si_p); |
| 0 | 705 |
| 706 if (valid_gimple_call_p (expr)) | |
| 707 { | |
| 708 /* The call has simplified to another call. */ | |
| 709 tree fn = CALL_EXPR_FN (expr); | |
| 710 unsigned i; | |
| 711 unsigned nargs = call_expr_nargs (expr); | |
| 111 | 712 vec<tree> args = vNULL; |
| 713 gcall *new_stmt; | |
| 0 | 714 |
| 715 if (nargs > 0) | |
| 716 { | |
| 111 | 717 args.create (nargs); |
| 718 args.safe_grow_cleared (nargs); | |
|
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719 |
| 0 | 720 for (i = 0; i < nargs; i++) |
| 111 | 721 args[i] = CALL_EXPR_ARG (expr, i); |
| 0 | 722 } |
| 723 | |
| 724 new_stmt = gimple_build_call_vec (fn, args); | |
| 111 | 725 finish_update_gimple_call (si_p, new_stmt, stmt); |
| 726 args.release (); | |
| 0 | 727 |
| 728 return true; | |
| 729 } | |
| 730 else if (valid_gimple_rhs_p (expr)) | |
| 731 { | |
| 111 | 732 tree lhs = gimple_call_lhs (stmt); |
| 733 gimple *new_stmt; | |
| 0 | 734 |
| 735 /* The call has simplified to an expression | |
| 736 that cannot be represented as a GIMPLE_CALL. */ | |
| 737 if (lhs) | |
| 738 { | |
| 739 /* A value is expected. | |
| 740 Introduce a new GIMPLE_ASSIGN statement. */ | |
| 741 STRIP_USELESS_TYPE_CONVERSION (expr); | |
| 742 new_stmt = gimple_build_assign (lhs, expr); | |
| 743 move_ssa_defining_stmt_for_defs (new_stmt, stmt); | |
|
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744 gimple_set_vuse (new_stmt, gimple_vuse (stmt)); |
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745 gimple_set_vdef (new_stmt, gimple_vdef (stmt)); |
| 0 | 746 } |
| 747 else if (!TREE_SIDE_EFFECTS (expr)) | |
| 748 { | |
| 749 /* No value is expected, and EXPR has no effect. | |
| 750 Replace it with an empty statement. */ | |
| 751 new_stmt = gimple_build_nop (); | |
|
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752 if (gimple_in_ssa_p (cfun)) |
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753 { |
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754 unlink_stmt_vdef (stmt); |
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755 release_defs (stmt); |
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756 } |
| 0 | 757 } |
| 758 else | |
| 759 { | |
| 760 /* No value is expected, but EXPR has an effect, | |
| 761 e.g., it could be a reference to a volatile | |
| 762 variable. Create an assignment statement | |
| 763 with a dummy (unused) lhs variable. */ | |
| 764 STRIP_USELESS_TYPE_CONVERSION (expr); | |
| 111 | 765 if (gimple_in_ssa_p (cfun)) |
| 766 lhs = make_ssa_name (TREE_TYPE (expr)); | |
| 767 else | |
| 768 lhs = create_tmp_var (TREE_TYPE (expr)); | |
| 0 | 769 new_stmt = gimple_build_assign (lhs, expr); |
|
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770 gimple_set_vuse (new_stmt, gimple_vuse (stmt)); |
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771 gimple_set_vdef (new_stmt, gimple_vdef (stmt)); |
| 0 | 772 move_ssa_defining_stmt_for_defs (new_stmt, stmt); |
| 773 } | |
| 774 gimple_set_location (new_stmt, gimple_location (stmt)); | |
| 775 gsi_replace (si_p, new_stmt, false); | |
| 776 return true; | |
| 777 } | |
| 778 else | |
| 779 /* The call simplified to an expression that is | |
| 780 not a valid GIMPLE RHS. */ | |
| 781 return false; | |
| 782 } | |
| 783 | |
| 784 | |
| 785 /* Entry point to the propagation engine. | |
| 786 | |
| 787 VISIT_STMT is called for every statement visited. | |
| 788 VISIT_PHI is called for every PHI node visited. */ | |
| 789 | |
| 790 void | |
| 791 ssa_propagate (ssa_prop_visit_stmt_fn visit_stmt, | |
| 792 ssa_prop_visit_phi_fn visit_phi) | |
| 793 { | |
| 794 ssa_prop_visit_stmt = visit_stmt; | |
| 795 ssa_prop_visit_phi = visit_phi; | |
| 796 | |
| 797 ssa_prop_init (); | |
| 798 | |
| 799 /* Iterate until the worklists are empty. */ | |
| 111 | 800 while (! cfg_blocks_empty_p () |
| 801 || ! bitmap_empty_p (ssa_edge_worklist)) | |
| 0 | 802 { |
| 111 | 803 /* First simulate whole blocks. */ |
| 804 if (! cfg_blocks_empty_p ()) | |
| 0 | 805 { |
| 806 /* Pull the next block to simulate off the worklist. */ | |
| 807 basic_block dest_block = cfg_blocks_get (); | |
| 808 simulate_block (dest_block); | |
| 111 | 809 continue; |
| 0 | 810 } |
| 811 | |
| 111 | 812 /* Then simulate from the SSA edge worklist. */ |
| 813 process_ssa_edge_worklist (); | |
| 0 | 814 } |
| 815 | |
| 816 ssa_prop_fini (); | |
| 817 } | |
| 818 | |
| 819 | |
| 820 /* Return true if STMT is of the form 'mem_ref = RHS', where 'mem_ref' | |
| 821 is a non-volatile pointer dereference, a structure reference or a | |
| 822 reference to a single _DECL. Ignore volatile memory references | |
| 823 because they are not interesting for the optimizers. */ | |
| 824 | |
| 825 bool | |
| 111 | 826 stmt_makes_single_store (gimple *stmt) |
| 0 | 827 { |
| 828 tree lhs; | |
| 829 | |
| 830 if (gimple_code (stmt) != GIMPLE_ASSIGN | |
| 831 && gimple_code (stmt) != GIMPLE_CALL) | |
| 832 return false; | |
| 833 | |
|
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834 if (!gimple_vdef (stmt)) |
| 0 | 835 return false; |
| 836 | |
| 837 lhs = gimple_get_lhs (stmt); | |
| 838 | |
| 839 /* A call statement may have a null LHS. */ | |
| 840 if (!lhs) | |
| 841 return false; | |
| 842 | |
| 843 return (!TREE_THIS_VOLATILE (lhs) | |
| 844 && (DECL_P (lhs) | |
| 845 || REFERENCE_CLASS_P (lhs))); | |
| 846 } | |
| 847 | |
| 848 | |
| 849 /* Propagation statistics. */ | |
| 850 struct prop_stats_d | |
| 851 { | |
| 852 long num_const_prop; | |
| 853 long num_copy_prop; | |
|
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854 long num_stmts_folded; |
| 0 | 855 long num_dce; |
| 856 }; | |
| 857 | |
| 858 static struct prop_stats_d prop_stats; | |
| 859 | |
| 860 /* Replace USE references in statement STMT with the values stored in | |
| 861 PROP_VALUE. Return true if at least one reference was replaced. */ | |
| 862 | |
| 111 | 863 bool |
| 864 replace_uses_in (gimple *stmt, ssa_prop_get_value_fn get_value) | |
| 0 | 865 { |
| 866 bool replaced = false; | |
| 867 use_operand_p use; | |
| 868 ssa_op_iter iter; | |
| 869 | |
| 870 FOR_EACH_SSA_USE_OPERAND (use, stmt, iter, SSA_OP_USE) | |
| 871 { | |
| 872 tree tuse = USE_FROM_PTR (use); | |
|
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873 tree val = (*get_value) (tuse); |
| 0 | 874 |
| 875 if (val == tuse || val == NULL_TREE) | |
| 876 continue; | |
| 877 | |
| 878 if (gimple_code (stmt) == GIMPLE_ASM | |
| 879 && !may_propagate_copy_into_asm (tuse)) | |
| 880 continue; | |
| 881 | |
| 882 if (!may_propagate_copy (tuse, val)) | |
| 883 continue; | |
| 884 | |
| 885 if (TREE_CODE (val) != SSA_NAME) | |
| 886 prop_stats.num_const_prop++; | |
| 887 else | |
| 888 prop_stats.num_copy_prop++; | |
| 889 | |
| 890 propagate_value (use, val); | |
| 891 | |
| 892 replaced = true; | |
| 893 } | |
| 894 | |
| 895 return replaced; | |
| 896 } | |
| 897 | |
| 898 | |
| 899 /* Replace propagated values into all the arguments for PHI using the | |
| 900 values from PROP_VALUE. */ | |
| 901 | |
| 111 | 902 static bool |
| 903 replace_phi_args_in (gphi *phi, ssa_prop_get_value_fn get_value) | |
| 0 | 904 { |
| 905 size_t i; | |
| 906 bool replaced = false; | |
| 907 | |
| 908 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 909 { | |
| 910 fprintf (dump_file, "Folding PHI node: "); | |
| 911 print_gimple_stmt (dump_file, phi, 0, TDF_SLIM); | |
| 912 } | |
| 913 | |
| 914 for (i = 0; i < gimple_phi_num_args (phi); i++) | |
| 915 { | |
| 916 tree arg = gimple_phi_arg_def (phi, i); | |
| 917 | |
| 918 if (TREE_CODE (arg) == SSA_NAME) | |
| 919 { | |
|
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920 tree val = (*get_value) (arg); |
| 0 | 921 |
| 922 if (val && val != arg && may_propagate_copy (arg, val)) | |
| 923 { | |
| 111 | 924 edge e = gimple_phi_arg_edge (phi, i); |
| 925 | |
| 0 | 926 if (TREE_CODE (val) != SSA_NAME) |
| 927 prop_stats.num_const_prop++; | |
| 928 else | |
| 929 prop_stats.num_copy_prop++; | |
| 930 | |
| 931 propagate_value (PHI_ARG_DEF_PTR (phi, i), val); | |
| 932 replaced = true; | |
| 933 | |
| 934 /* If we propagated a copy and this argument flows | |
| 935 through an abnormal edge, update the replacement | |
| 936 accordingly. */ | |
| 937 if (TREE_CODE (val) == SSA_NAME | |
| 111 | 938 && e->flags & EDGE_ABNORMAL |
| 939 && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val)) | |
| 940 { | |
| 941 /* This can only occur for virtual operands, since | |
| 942 for the real ones SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val)) | |
| 943 would prevent replacement. */ | |
| 944 gcc_checking_assert (virtual_operand_p (val)); | |
| 945 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (val) = 1; | |
| 946 } | |
| 0 | 947 } |
| 948 } | |
| 949 } | |
|
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950 |
| 0 | 951 if (dump_file && (dump_flags & TDF_DETAILS)) |
| 952 { | |
| 953 if (!replaced) | |
| 954 fprintf (dump_file, "No folding possible\n"); | |
| 955 else | |
| 956 { | |
| 957 fprintf (dump_file, "Folded into: "); | |
| 958 print_gimple_stmt (dump_file, phi, 0, TDF_SLIM); | |
| 959 fprintf (dump_file, "\n"); | |
| 960 } | |
| 961 } | |
| 111 | 962 |
| 963 return replaced; | |
| 0 | 964 } |
| 965 | |
| 966 | |
| 111 | 967 class substitute_and_fold_dom_walker : public dom_walker |
| 968 { | |
| 969 public: | |
| 970 substitute_and_fold_dom_walker (cdi_direction direction, | |
| 971 ssa_prop_get_value_fn get_value_fn_, | |
| 972 ssa_prop_fold_stmt_fn fold_fn_) | |
| 973 : dom_walker (direction), get_value_fn (get_value_fn_), | |
| 974 fold_fn (fold_fn_), something_changed (false) | |
| 975 { | |
| 976 stmts_to_remove.create (0); | |
| 977 stmts_to_fixup.create (0); | |
| 978 need_eh_cleanup = BITMAP_ALLOC (NULL); | |
| 979 } | |
| 980 ~substitute_and_fold_dom_walker () | |
| 981 { | |
| 982 stmts_to_remove.release (); | |
| 983 stmts_to_fixup.release (); | |
| 984 BITMAP_FREE (need_eh_cleanup); | |
| 985 } | |
| 986 | |
| 987 virtual edge before_dom_children (basic_block); | |
| 988 virtual void after_dom_children (basic_block) {} | |
| 989 | |
| 990 ssa_prop_get_value_fn get_value_fn; | |
| 991 ssa_prop_fold_stmt_fn fold_fn; | |
| 992 bool something_changed; | |
| 993 vec<gimple *> stmts_to_remove; | |
| 994 vec<gimple *> stmts_to_fixup; | |
| 995 bitmap need_eh_cleanup; | |
| 996 }; | |
| 997 | |
| 998 edge | |
| 999 substitute_and_fold_dom_walker::before_dom_children (basic_block bb) | |
| 1000 { | |
| 1001 /* Propagate known values into PHI nodes. */ | |
| 1002 for (gphi_iterator i = gsi_start_phis (bb); | |
| 1003 !gsi_end_p (i); | |
| 1004 gsi_next (&i)) | |
| 1005 { | |
| 1006 gphi *phi = i.phi (); | |
| 1007 tree res = gimple_phi_result (phi); | |
| 1008 if (virtual_operand_p (res)) | |
| 1009 continue; | |
| 1010 if (res && TREE_CODE (res) == SSA_NAME) | |
| 1011 { | |
| 1012 tree sprime = get_value_fn (res); | |
| 1013 if (sprime | |
| 1014 && sprime != res | |
| 1015 && may_propagate_copy (res, sprime)) | |
| 1016 { | |
| 1017 stmts_to_remove.safe_push (phi); | |
| 1018 continue; | |
| 1019 } | |
| 1020 } | |
| 1021 something_changed |= replace_phi_args_in (phi, get_value_fn); | |
| 1022 } | |
| 1023 | |
| 1024 /* Propagate known values into stmts. In some case it exposes | |
| 1025 more trivially deletable stmts to walk backward. */ | |
| 1026 for (gimple_stmt_iterator i = gsi_start_bb (bb); | |
| 1027 !gsi_end_p (i); | |
| 1028 gsi_next (&i)) | |
| 1029 { | |
| 1030 bool did_replace; | |
| 1031 gimple *stmt = gsi_stmt (i); | |
| 1032 | |
| 1033 /* No point propagating into a stmt we have a value for we | |
| 1034 can propagate into all uses. Mark it for removal instead. */ | |
| 1035 tree lhs = gimple_get_lhs (stmt); | |
| 1036 if (lhs && TREE_CODE (lhs) == SSA_NAME) | |
| 1037 { | |
| 1038 tree sprime = get_value_fn (lhs); | |
| 1039 if (sprime | |
| 1040 && sprime != lhs | |
| 1041 && may_propagate_copy (lhs, sprime) | |
| 1042 && !stmt_could_throw_p (stmt) | |
| 1043 && !gimple_has_side_effects (stmt) | |
| 1044 /* We have to leave ASSERT_EXPRs around for jump-threading. */ | |
| 1045 && (!is_gimple_assign (stmt) | |
| 1046 || gimple_assign_rhs_code (stmt) != ASSERT_EXPR)) | |
| 1047 { | |
| 1048 stmts_to_remove.safe_push (stmt); | |
| 1049 continue; | |
| 1050 } | |
| 1051 } | |
| 1052 | |
| 1053 /* Replace the statement with its folded version and mark it | |
| 1054 folded. */ | |
| 1055 did_replace = false; | |
| 1056 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 1057 { | |
| 1058 fprintf (dump_file, "Folding statement: "); | |
| 1059 print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); | |
| 1060 } | |
| 1061 | |
| 1062 gimple *old_stmt = stmt; | |
| 1063 bool was_noreturn = (is_gimple_call (stmt) | |
| 1064 && gimple_call_noreturn_p (stmt)); | |
| 1065 | |
| 1066 /* Replace real uses in the statement. */ | |
| 1067 did_replace |= replace_uses_in (stmt, get_value_fn); | |
| 1068 | |
| 1069 /* If we made a replacement, fold the statement. */ | |
| 1070 if (did_replace) | |
| 1071 { | |
| 1072 fold_stmt (&i, follow_single_use_edges); | |
| 1073 stmt = gsi_stmt (i); | |
| 1074 gimple_set_modified (stmt, true); | |
| 1075 } | |
| 1076 | |
| 1077 /* Some statements may be simplified using propagator | |
| 1078 specific information. Do this before propagating | |
| 1079 into the stmt to not disturb pass specific information. */ | |
| 1080 if (fold_fn) | |
| 1081 { | |
| 1082 update_stmt_if_modified (stmt); | |
| 1083 if ((*fold_fn)(&i)) | |
| 1084 { | |
| 1085 did_replace = true; | |
| 1086 prop_stats.num_stmts_folded++; | |
| 1087 stmt = gsi_stmt (i); | |
| 1088 gimple_set_modified (stmt, true); | |
| 1089 } | |
| 1090 } | |
| 1091 | |
| 1092 /* If this is a control statement the propagator left edges | |
| 1093 unexecuted on force the condition in a way consistent with | |
| 1094 that. See PR66945 for cases where the propagator can end | |
| 1095 up with a different idea of a taken edge than folding | |
| 1096 (once undefined behavior is involved). */ | |
| 1097 if (gimple_code (stmt) == GIMPLE_COND) | |
| 1098 { | |
| 1099 if ((EDGE_SUCC (bb, 0)->flags & EDGE_EXECUTABLE) | |
| 1100 ^ (EDGE_SUCC (bb, 1)->flags & EDGE_EXECUTABLE)) | |
| 1101 { | |
| 1102 if (((EDGE_SUCC (bb, 0)->flags & EDGE_TRUE_VALUE) != 0) | |
| 1103 == ((EDGE_SUCC (bb, 0)->flags & EDGE_EXECUTABLE) != 0)) | |
| 1104 gimple_cond_make_true (as_a <gcond *> (stmt)); | |
| 1105 else | |
| 1106 gimple_cond_make_false (as_a <gcond *> (stmt)); | |
| 1107 gimple_set_modified (stmt, true); | |
| 1108 did_replace = true; | |
| 1109 } | |
| 1110 } | |
| 1111 | |
| 1112 /* Now cleanup. */ | |
| 1113 if (did_replace) | |
| 1114 { | |
| 1115 /* If we cleaned up EH information from the statement, | |
| 1116 remove EH edges. */ | |
| 1117 if (maybe_clean_or_replace_eh_stmt (old_stmt, stmt)) | |
| 1118 bitmap_set_bit (need_eh_cleanup, bb->index); | |
| 1119 | |
| 1120 /* If we turned a not noreturn call into a noreturn one | |
| 1121 schedule it for fixup. */ | |
| 1122 if (!was_noreturn | |
| 1123 && is_gimple_call (stmt) | |
| 1124 && gimple_call_noreturn_p (stmt)) | |
| 1125 stmts_to_fixup.safe_push (stmt); | |
| 1126 | |
| 1127 if (gimple_assign_single_p (stmt)) | |
| 1128 { | |
| 1129 tree rhs = gimple_assign_rhs1 (stmt); | |
| 1130 | |
| 1131 if (TREE_CODE (rhs) == ADDR_EXPR) | |
| 1132 recompute_tree_invariant_for_addr_expr (rhs); | |
| 1133 } | |
| 1134 | |
| 1135 /* Determine what needs to be done to update the SSA form. */ | |
| 1136 update_stmt_if_modified (stmt); | |
| 1137 if (!is_gimple_debug (stmt)) | |
| 1138 something_changed = true; | |
| 1139 } | |
| 1140 | |
| 1141 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 1142 { | |
| 1143 if (did_replace) | |
| 1144 { | |
| 1145 fprintf (dump_file, "Folded into: "); | |
| 1146 print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); | |
| 1147 fprintf (dump_file, "\n"); | |
| 1148 } | |
| 1149 else | |
| 1150 fprintf (dump_file, "Not folded\n"); | |
| 1151 } | |
| 1152 } | |
| 1153 return NULL; | |
| 1154 } | |
| 1155 | |
| 1156 | |
| 1157 | |
| 0 | 1158 /* Perform final substitution and folding of propagated values. |
| 1159 | |
| 1160 PROP_VALUE[I] contains the single value that should be substituted | |
| 1161 at every use of SSA name N_I. If PROP_VALUE is NULL, no values are | |
| 1162 substituted. | |
| 1163 | |
|
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1164 If FOLD_FN is non-NULL the function will be invoked on all statements |
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1165 before propagating values for pass specific simplification. |
| 0 | 1166 |
|
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1167 DO_DCE is true if trivially dead stmts can be removed. |
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1168 |
| 111 | 1169 If DO_DCE is true, the statements within a BB are walked from |
| 1170 last to first element. Otherwise we scan from first to last element. | |
| 1171 | |
| 0 | 1172 Return TRUE when something changed. */ |
| 1173 | |
| 1174 bool | |
|
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1175 substitute_and_fold (ssa_prop_get_value_fn get_value_fn, |
| 111 | 1176 ssa_prop_fold_stmt_fn fold_fn) |
| 0 | 1177 { |
| 111 | 1178 gcc_assert (get_value_fn); |
| 0 | 1179 |
| 1180 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 1181 fprintf (dump_file, "\nSubstituting values and folding statements\n\n"); | |
| 1182 | |
| 1183 memset (&prop_stats, 0, sizeof (prop_stats)); | |
| 1184 | |
| 111 | 1185 calculate_dominance_info (CDI_DOMINATORS); |
| 1186 substitute_and_fold_dom_walker walker(CDI_DOMINATORS, | |
| 1187 get_value_fn, fold_fn); | |
| 1188 walker.walk (ENTRY_BLOCK_PTR_FOR_FN (cfun)); | |
| 0 | 1189 |
| 111 | 1190 /* We cannot remove stmts during the BB walk, especially not release |
| 1191 SSA names there as that destroys the lattice of our callers. | |
| 1192 Remove stmts in reverse order to make debug stmt creation possible. */ | |
| 1193 while (!walker.stmts_to_remove.is_empty ()) | |
| 1194 { | |
| 1195 gimple *stmt = walker.stmts_to_remove.pop (); | |
| 1196 if (dump_file && dump_flags & TDF_DETAILS) | |
| 1197 { | |
| 1198 fprintf (dump_file, "Removing dead stmt "); | |
| 1199 print_gimple_stmt (dump_file, stmt, 0); | |
| 1200 fprintf (dump_file, "\n"); | |
| 1201 } | |
| 1202 prop_stats.num_dce++; | |
| 1203 gimple_stmt_iterator gsi = gsi_for_stmt (stmt); | |
| 1204 if (gimple_code (stmt) == GIMPLE_PHI) | |
| 1205 remove_phi_node (&gsi, true); | |
| 1206 else | |
| 1207 { | |
| 1208 unlink_stmt_vdef (stmt); | |
| 1209 gsi_remove (&gsi, true); | |
| 1210 release_defs (stmt); | |
| 1211 } | |
| 1212 } | |
|
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1213 |
| 111 | 1214 if (!bitmap_empty_p (walker.need_eh_cleanup)) |
| 1215 gimple_purge_all_dead_eh_edges (walker.need_eh_cleanup); | |
| 0 | 1216 |
| 111 | 1217 /* Fixup stmts that became noreturn calls. This may require splitting |
| 1218 blocks and thus isn't possible during the dominator walk. Do this | |
| 1219 in reverse order so we don't inadvertedly remove a stmt we want to | |
| 1220 fixup by visiting a dominating now noreturn call first. */ | |
| 1221 while (!walker.stmts_to_fixup.is_empty ()) | |
| 1222 { | |
| 1223 gimple *stmt = walker.stmts_to_fixup.pop (); | |
| 1224 if (dump_file && dump_flags & TDF_DETAILS) | |
| 1225 { | |
| 1226 fprintf (dump_file, "Fixing up noreturn call "); | |
| 1227 print_gimple_stmt (dump_file, stmt, 0); | |
| 1228 fprintf (dump_file, "\n"); | |
| 0 | 1229 } |
| 111 | 1230 fixup_noreturn_call (stmt); |
| 0 | 1231 } |
| 1232 | |
| 1233 statistics_counter_event (cfun, "Constants propagated", | |
| 1234 prop_stats.num_const_prop); | |
| 1235 statistics_counter_event (cfun, "Copies propagated", | |
| 1236 prop_stats.num_copy_prop); | |
|
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1237 statistics_counter_event (cfun, "Statements folded", |
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1238 prop_stats.num_stmts_folded); |
| 0 | 1239 statistics_counter_event (cfun, "Statements deleted", |
| 1240 prop_stats.num_dce); | |
| 111 | 1241 |
| 1242 return walker.something_changed; | |
| 1243 } | |
| 1244 | |
| 1245 | |
| 1246 /* Return true if we may propagate ORIG into DEST, false otherwise. */ | |
| 1247 | |
| 1248 bool | |
| 1249 may_propagate_copy (tree dest, tree orig) | |
| 1250 { | |
| 1251 tree type_d = TREE_TYPE (dest); | |
| 1252 tree type_o = TREE_TYPE (orig); | |
| 1253 | |
| 1254 /* If ORIG is a default definition which flows in from an abnormal edge | |
| 1255 then the copy can be propagated. It is important that we do so to avoid | |
| 1256 uninitialized copies. */ | |
| 1257 if (TREE_CODE (orig) == SSA_NAME | |
| 1258 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig) | |
| 1259 && SSA_NAME_IS_DEFAULT_DEF (orig) | |
| 1260 && (SSA_NAME_VAR (orig) == NULL_TREE | |
| 1261 || TREE_CODE (SSA_NAME_VAR (orig)) == VAR_DECL)) | |
| 1262 ; | |
| 1263 /* Otherwise if ORIG just flows in from an abnormal edge then the copy cannot | |
| 1264 be propagated. */ | |
| 1265 else if (TREE_CODE (orig) == SSA_NAME | |
| 1266 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig)) | |
| 1267 return false; | |
| 1268 /* Similarly if DEST flows in from an abnormal edge then the copy cannot be | |
| 1269 propagated. */ | |
| 1270 else if (TREE_CODE (dest) == SSA_NAME | |
| 1271 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (dest)) | |
| 1272 return false; | |
| 1273 | |
| 1274 /* Do not copy between types for which we *do* need a conversion. */ | |
| 1275 if (!useless_type_conversion_p (type_d, type_o)) | |
| 1276 return false; | |
| 1277 | |
| 1278 /* Generally propagating virtual operands is not ok as that may | |
| 1279 create overlapping life-ranges. */ | |
| 1280 if (TREE_CODE (dest) == SSA_NAME && virtual_operand_p (dest)) | |
| 1281 return false; | |
| 1282 | |
| 1283 /* Anything else is OK. */ | |
| 1284 return true; | |
| 1285 } | |
| 1286 | |
| 1287 /* Like may_propagate_copy, but use as the destination expression | |
| 1288 the principal expression (typically, the RHS) contained in | |
| 1289 statement DEST. This is more efficient when working with the | |
| 1290 gimple tuples representation. */ | |
| 1291 | |
| 1292 bool | |
| 1293 may_propagate_copy_into_stmt (gimple *dest, tree orig) | |
| 1294 { | |
| 1295 tree type_d; | |
| 1296 tree type_o; | |
| 1297 | |
| 1298 /* If the statement is a switch or a single-rhs assignment, | |
| 1299 then the expression to be replaced by the propagation may | |
| 1300 be an SSA_NAME. Fortunately, there is an explicit tree | |
| 1301 for the expression, so we delegate to may_propagate_copy. */ | |
| 1302 | |
| 1303 if (gimple_assign_single_p (dest)) | |
| 1304 return may_propagate_copy (gimple_assign_rhs1 (dest), orig); | |
| 1305 else if (gswitch *dest_swtch = dyn_cast <gswitch *> (dest)) | |
| 1306 return may_propagate_copy (gimple_switch_index (dest_swtch), orig); | |
| 1307 | |
| 1308 /* In other cases, the expression is not materialized, so there | |
| 1309 is no destination to pass to may_propagate_copy. On the other | |
| 1310 hand, the expression cannot be an SSA_NAME, so the analysis | |
| 1311 is much simpler. */ | |
| 1312 | |
| 1313 if (TREE_CODE (orig) == SSA_NAME | |
| 1314 && SSA_NAME_OCCURS_IN_ABNORMAL_PHI (orig)) | |
| 1315 return false; | |
| 1316 | |
| 1317 if (is_gimple_assign (dest)) | |
| 1318 type_d = TREE_TYPE (gimple_assign_lhs (dest)); | |
| 1319 else if (gimple_code (dest) == GIMPLE_COND) | |
| 1320 type_d = boolean_type_node; | |
| 1321 else if (is_gimple_call (dest) | |
| 1322 && gimple_call_lhs (dest) != NULL_TREE) | |
| 1323 type_d = TREE_TYPE (gimple_call_lhs (dest)); | |
| 1324 else | |
| 1325 gcc_unreachable (); | |
| 1326 | |
| 1327 type_o = TREE_TYPE (orig); | |
| 1328 | |
| 1329 if (!useless_type_conversion_p (type_d, type_o)) | |
| 1330 return false; | |
| 1331 | |
| 1332 return true; | |
| 1333 } | |
| 1334 | |
| 1335 /* Similarly, but we know that we're propagating into an ASM_EXPR. */ | |
| 1336 | |
| 1337 bool | |
| 1338 may_propagate_copy_into_asm (tree dest ATTRIBUTE_UNUSED) | |
| 1339 { | |
| 1340 return true; | |
| 0 | 1341 } |
| 1342 | |
| 111 | 1343 |
| 1344 /* Common code for propagate_value and replace_exp. | |
| 1345 | |
| 1346 Replace use operand OP_P with VAL. FOR_PROPAGATION indicates if the | |
| 1347 replacement is done to propagate a value or not. */ | |
| 1348 | |
| 1349 static void | |
| 1350 replace_exp_1 (use_operand_p op_p, tree val, | |
| 1351 bool for_propagation ATTRIBUTE_UNUSED) | |
| 1352 { | |
| 1353 if (flag_checking) | |
| 1354 { | |
| 1355 tree op = USE_FROM_PTR (op_p); | |
| 1356 gcc_assert (!(for_propagation | |
| 1357 && TREE_CODE (op) == SSA_NAME | |
| 1358 && TREE_CODE (val) == SSA_NAME | |
| 1359 && !may_propagate_copy (op, val))); | |
| 1360 } | |
| 1361 | |
| 1362 if (TREE_CODE (val) == SSA_NAME) | |
| 1363 SET_USE (op_p, val); | |
| 1364 else | |
| 1365 SET_USE (op_p, unshare_expr (val)); | |
| 1366 } | |
| 1367 | |
| 1368 | |
| 1369 /* Propagate the value VAL (assumed to be a constant or another SSA_NAME) | |
| 1370 into the operand pointed to by OP_P. | |
| 1371 | |
| 1372 Use this version for const/copy propagation as it will perform additional | |
| 1373 checks to ensure validity of the const/copy propagation. */ | |
| 1374 | |
| 1375 void | |
| 1376 propagate_value (use_operand_p op_p, tree val) | |
| 1377 { | |
| 1378 replace_exp_1 (op_p, val, true); | |
| 1379 } | |
| 1380 | |
| 1381 /* Replace *OP_P with value VAL (assumed to be a constant or another SSA_NAME). | |
| 1382 | |
| 1383 Use this version when not const/copy propagating values. For example, | |
| 1384 PRE uses this version when building expressions as they would appear | |
| 1385 in specific blocks taking into account actions of PHI nodes. | |
| 1386 | |
| 1387 The statement in which an expression has been replaced should be | |
| 1388 folded using fold_stmt_inplace. */ | |
| 1389 | |
| 1390 void | |
| 1391 replace_exp (use_operand_p op_p, tree val) | |
| 1392 { | |
| 1393 replace_exp_1 (op_p, val, false); | |
| 1394 } | |
| 1395 | |
| 1396 | |
| 1397 /* Propagate the value VAL (assumed to be a constant or another SSA_NAME) | |
| 1398 into the tree pointed to by OP_P. | |
| 1399 | |
| 1400 Use this version for const/copy propagation when SSA operands are not | |
| 1401 available. It will perform the additional checks to ensure validity of | |
| 1402 the const/copy propagation, but will not update any operand information. | |
| 1403 Be sure to mark the stmt as modified. */ | |
| 1404 | |
| 1405 void | |
| 1406 propagate_tree_value (tree *op_p, tree val) | |
| 1407 { | |
| 1408 if (TREE_CODE (val) == SSA_NAME) | |
| 1409 *op_p = val; | |
| 1410 else | |
| 1411 *op_p = unshare_expr (val); | |
| 1412 } | |
| 1413 | |
| 1414 | |
| 1415 /* Like propagate_tree_value, but use as the operand to replace | |
| 1416 the principal expression (typically, the RHS) contained in the | |
| 1417 statement referenced by iterator GSI. Note that it is not | |
| 1418 always possible to update the statement in-place, so a new | |
| 1419 statement may be created to replace the original. */ | |
| 1420 | |
| 1421 void | |
| 1422 propagate_tree_value_into_stmt (gimple_stmt_iterator *gsi, tree val) | |
| 1423 { | |
| 1424 gimple *stmt = gsi_stmt (*gsi); | |
| 1425 | |
| 1426 if (is_gimple_assign (stmt)) | |
| 1427 { | |
| 1428 tree expr = NULL_TREE; | |
| 1429 if (gimple_assign_single_p (stmt)) | |
| 1430 expr = gimple_assign_rhs1 (stmt); | |
| 1431 propagate_tree_value (&expr, val); | |
| 1432 gimple_assign_set_rhs_from_tree (gsi, expr); | |
| 1433 } | |
| 1434 else if (gcond *cond_stmt = dyn_cast <gcond *> (stmt)) | |
| 1435 { | |
| 1436 tree lhs = NULL_TREE; | |
| 1437 tree rhs = build_zero_cst (TREE_TYPE (val)); | |
| 1438 propagate_tree_value (&lhs, val); | |
| 1439 gimple_cond_set_code (cond_stmt, NE_EXPR); | |
| 1440 gimple_cond_set_lhs (cond_stmt, lhs); | |
| 1441 gimple_cond_set_rhs (cond_stmt, rhs); | |
| 1442 } | |
| 1443 else if (is_gimple_call (stmt) | |
| 1444 && gimple_call_lhs (stmt) != NULL_TREE) | |
| 1445 { | |
| 1446 tree expr = NULL_TREE; | |
| 1447 bool res; | |
| 1448 propagate_tree_value (&expr, val); | |
| 1449 res = update_call_from_tree (gsi, expr); | |
| 1450 gcc_assert (res); | |
| 1451 } | |
| 1452 else if (gswitch *swtch_stmt = dyn_cast <gswitch *> (stmt)) | |
| 1453 propagate_tree_value (gimple_switch_index_ptr (swtch_stmt), val); | |
| 1454 else | |
| 1455 gcc_unreachable (); | |
| 1456 } |