Mercurial > hg > CbC > CbC_gcc
annotate gcc/tree-ssa-dce.c @ 63:b7f97abdc517 gcc-4.6-20100522
update gcc from gcc-4.5.0 to gcc-4.6
| author | ryoma <e075725@ie.u-ryukyu.ac.jp> |
|---|---|
| date | Mon, 24 May 2010 12:47:05 +0900 |
| parents | 77e2b8dfacca |
| children | f6334be47118 |
| rev | line source |
|---|---|
| 0 | 1 /* Dead code elimination pass for the GNU compiler. |
|
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2 Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 |
| 0 | 3 Free Software Foundation, Inc. |
| 4 Contributed by Ben Elliston <bje@redhat.com> | |
| 5 and Andrew MacLeod <amacleod@redhat.com> | |
| 6 Adapted to use control dependence by Steven Bosscher, SUSE Labs. | |
|
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7 |
| 0 | 8 This file is part of GCC. |
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9 |
| 0 | 10 GCC is free software; you can redistribute it and/or modify it |
| 11 under the terms of the GNU General Public License as published by the | |
| 12 Free Software Foundation; either version 3, or (at your option) any | |
| 13 later version. | |
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14 |
| 0 | 15 GCC is distributed in the hope that it will be useful, but WITHOUT |
| 16 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 17 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 18 for more details. | |
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19 |
| 0 | 20 You should have received a copy of the GNU General Public License |
| 21 along with GCC; see the file COPYING3. If not see | |
| 22 <http://www.gnu.org/licenses/>. */ | |
| 23 | |
| 24 /* Dead code elimination. | |
| 25 | |
| 26 References: | |
| 27 | |
| 28 Building an Optimizing Compiler, | |
| 29 Robert Morgan, Butterworth-Heinemann, 1998, Section 8.9. | |
| 30 | |
| 31 Advanced Compiler Design and Implementation, | |
| 32 Steven Muchnick, Morgan Kaufmann, 1997, Section 18.10. | |
| 33 | |
| 34 Dead-code elimination is the removal of statements which have no | |
| 35 impact on the program's output. "Dead statements" have no impact | |
| 36 on the program's output, while "necessary statements" may have | |
| 37 impact on the output. | |
| 38 | |
| 39 The algorithm consists of three phases: | |
| 40 1. Marking as necessary all statements known to be necessary, | |
| 41 e.g. most function calls, writing a value to memory, etc; | |
| 42 2. Propagating necessary statements, e.g., the statements | |
| 43 giving values to operands in necessary statements; and | |
| 44 3. Removing dead statements. */ | |
| 45 | |
| 46 #include "config.h" | |
| 47 #include "system.h" | |
| 48 #include "coretypes.h" | |
| 49 #include "tm.h" | |
| 50 | |
| 51 #include "tree.h" | |
| 52 #include "diagnostic.h" | |
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53 #include "tree-pretty-print.h" |
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54 #include "gimple-pretty-print.h" |
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55 #include "basic-block.h" |
| 0 | 56 #include "tree-flow.h" |
| 57 #include "gimple.h" | |
| 58 #include "tree-dump.h" | |
| 59 #include "tree-pass.h" | |
| 60 #include "timevar.h" | |
| 61 #include "flags.h" | |
| 62 #include "cfgloop.h" | |
| 63 #include "tree-scalar-evolution.h" | |
| 64 | |
| 65 static struct stmt_stats | |
| 66 { | |
| 67 int total; | |
| 68 int total_phis; | |
| 69 int removed; | |
| 70 int removed_phis; | |
| 71 } stats; | |
| 72 | |
| 73 #define STMT_NECESSARY GF_PLF_1 | |
| 74 | |
| 75 static VEC(gimple,heap) *worklist; | |
| 76 | |
| 77 /* Vector indicating an SSA name has already been processed and marked | |
| 78 as necessary. */ | |
| 79 static sbitmap processed; | |
| 80 | |
| 81 /* Vector indicating that last_stmt if a basic block has already been | |
| 82 marked as necessary. */ | |
| 83 static sbitmap last_stmt_necessary; | |
| 84 | |
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85 /* Vector indicating that BB contains statements that are live. */ |
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86 static sbitmap bb_contains_live_stmts; |
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87 |
| 0 | 88 /* Before we can determine whether a control branch is dead, we need to |
| 89 compute which blocks are control dependent on which edges. | |
| 90 | |
| 91 We expect each block to be control dependent on very few edges so we | |
| 92 use a bitmap for each block recording its edges. An array holds the | |
| 93 bitmap. The Ith bit in the bitmap is set if that block is dependent | |
| 94 on the Ith edge. */ | |
| 95 static bitmap *control_dependence_map; | |
| 96 | |
| 97 /* Vector indicating that a basic block has already had all the edges | |
| 98 processed that it is control dependent on. */ | |
| 99 static sbitmap visited_control_parents; | |
| 100 | |
| 101 /* TRUE if this pass alters the CFG (by removing control statements). | |
| 102 FALSE otherwise. | |
| 103 | |
| 104 If this pass alters the CFG, then it will arrange for the dominators | |
| 105 to be recomputed. */ | |
| 106 static bool cfg_altered; | |
| 107 | |
| 108 /* Execute code that follows the macro for each edge (given number | |
| 109 EDGE_NUMBER within the CODE) for which the block with index N is | |
| 110 control dependent. */ | |
| 111 #define EXECUTE_IF_CONTROL_DEPENDENT(BI, N, EDGE_NUMBER) \ | |
| 112 EXECUTE_IF_SET_IN_BITMAP (control_dependence_map[(N)], 0, \ | |
| 113 (EDGE_NUMBER), (BI)) | |
| 114 | |
| 115 | |
| 116 /* Indicate block BB is control dependent on an edge with index EDGE_INDEX. */ | |
| 117 static inline void | |
| 118 set_control_dependence_map_bit (basic_block bb, int edge_index) | |
| 119 { | |
| 120 if (bb == ENTRY_BLOCK_PTR) | |
| 121 return; | |
| 122 gcc_assert (bb != EXIT_BLOCK_PTR); | |
| 123 bitmap_set_bit (control_dependence_map[bb->index], edge_index); | |
| 124 } | |
| 125 | |
| 126 /* Clear all control dependences for block BB. */ | |
| 127 static inline void | |
| 128 clear_control_dependence_bitmap (basic_block bb) | |
| 129 { | |
| 130 bitmap_clear (control_dependence_map[bb->index]); | |
| 131 } | |
| 132 | |
| 133 | |
| 134 /* Find the immediate postdominator PDOM of the specified basic block BLOCK. | |
| 135 This function is necessary because some blocks have negative numbers. */ | |
| 136 | |
| 137 static inline basic_block | |
| 138 find_pdom (basic_block block) | |
| 139 { | |
| 140 gcc_assert (block != ENTRY_BLOCK_PTR); | |
| 141 | |
| 142 if (block == EXIT_BLOCK_PTR) | |
| 143 return EXIT_BLOCK_PTR; | |
| 144 else | |
| 145 { | |
| 146 basic_block bb = get_immediate_dominator (CDI_POST_DOMINATORS, block); | |
| 147 if (! bb) | |
| 148 return EXIT_BLOCK_PTR; | |
| 149 return bb; | |
| 150 } | |
| 151 } | |
| 152 | |
| 153 | |
| 154 /* Determine all blocks' control dependences on the given edge with edge_list | |
| 155 EL index EDGE_INDEX, ala Morgan, Section 3.6. */ | |
| 156 | |
| 157 static void | |
| 158 find_control_dependence (struct edge_list *el, int edge_index) | |
| 159 { | |
| 160 basic_block current_block; | |
| 161 basic_block ending_block; | |
| 162 | |
| 163 gcc_assert (INDEX_EDGE_PRED_BB (el, edge_index) != EXIT_BLOCK_PTR); | |
| 164 | |
| 165 if (INDEX_EDGE_PRED_BB (el, edge_index) == ENTRY_BLOCK_PTR) | |
| 166 ending_block = single_succ (ENTRY_BLOCK_PTR); | |
| 167 else | |
| 168 ending_block = find_pdom (INDEX_EDGE_PRED_BB (el, edge_index)); | |
| 169 | |
| 170 for (current_block = INDEX_EDGE_SUCC_BB (el, edge_index); | |
| 171 current_block != ending_block && current_block != EXIT_BLOCK_PTR; | |
| 172 current_block = find_pdom (current_block)) | |
| 173 { | |
| 174 edge e = INDEX_EDGE (el, edge_index); | |
| 175 | |
| 176 /* For abnormal edges, we don't make current_block control | |
| 177 dependent because instructions that throw are always necessary | |
| 178 anyway. */ | |
| 179 if (e->flags & EDGE_ABNORMAL) | |
| 180 continue; | |
| 181 | |
| 182 set_control_dependence_map_bit (current_block, edge_index); | |
| 183 } | |
| 184 } | |
| 185 | |
| 186 | |
| 187 /* Record all blocks' control dependences on all edges in the edge | |
| 188 list EL, ala Morgan, Section 3.6. */ | |
| 189 | |
| 190 static void | |
| 191 find_all_control_dependences (struct edge_list *el) | |
| 192 { | |
| 193 int i; | |
| 194 | |
| 195 for (i = 0; i < NUM_EDGES (el); ++i) | |
| 196 find_control_dependence (el, i); | |
| 197 } | |
| 198 | |
| 199 /* If STMT is not already marked necessary, mark it, and add it to the | |
| 200 worklist if ADD_TO_WORKLIST is true. */ | |
| 201 static inline void | |
| 202 mark_stmt_necessary (gimple stmt, bool add_to_worklist) | |
| 203 { | |
| 204 gcc_assert (stmt); | |
| 205 | |
| 206 if (gimple_plf (stmt, STMT_NECESSARY)) | |
| 207 return; | |
| 208 | |
| 209 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 210 { | |
| 211 fprintf (dump_file, "Marking useful stmt: "); | |
| 212 print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); | |
| 213 fprintf (dump_file, "\n"); | |
| 214 } | |
| 215 | |
| 216 gimple_set_plf (stmt, STMT_NECESSARY, true); | |
| 217 if (add_to_worklist) | |
| 218 VEC_safe_push (gimple, heap, worklist, stmt); | |
|
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219 if (bb_contains_live_stmts && !is_gimple_debug (stmt)) |
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220 SET_BIT (bb_contains_live_stmts, gimple_bb (stmt)->index); |
| 0 | 221 } |
| 222 | |
| 223 | |
| 224 /* Mark the statement defining operand OP as necessary. */ | |
| 225 | |
| 226 static inline void | |
| 227 mark_operand_necessary (tree op) | |
| 228 { | |
| 229 gimple stmt; | |
| 230 int ver; | |
| 231 | |
| 232 gcc_assert (op); | |
| 233 | |
| 234 ver = SSA_NAME_VERSION (op); | |
| 235 if (TEST_BIT (processed, ver)) | |
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236 { |
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237 stmt = SSA_NAME_DEF_STMT (op); |
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238 gcc_assert (gimple_nop_p (stmt) |
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239 || gimple_plf (stmt, STMT_NECESSARY)); |
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240 return; |
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241 } |
| 0 | 242 SET_BIT (processed, ver); |
| 243 | |
| 244 stmt = SSA_NAME_DEF_STMT (op); | |
| 245 gcc_assert (stmt); | |
| 246 | |
| 247 if (gimple_plf (stmt, STMT_NECESSARY) || gimple_nop_p (stmt)) | |
| 248 return; | |
| 249 | |
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250 if (dump_file && (dump_flags & TDF_DETAILS)) |
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251 { |
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252 fprintf (dump_file, "marking necessary through "); |
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253 print_generic_expr (dump_file, op, 0); |
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254 fprintf (dump_file, " stmt "); |
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255 print_gimple_stmt (dump_file, stmt, 0, 0); |
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256 } |
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257 |
| 0 | 258 gimple_set_plf (stmt, STMT_NECESSARY, true); |
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259 if (bb_contains_live_stmts) |
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260 SET_BIT (bb_contains_live_stmts, gimple_bb (stmt)->index); |
| 0 | 261 VEC_safe_push (gimple, heap, worklist, stmt); |
| 262 } | |
| 263 | |
| 264 | |
| 265 /* Mark STMT as necessary if it obviously is. Add it to the worklist if | |
| 266 it can make other statements necessary. | |
| 267 | |
| 268 If AGGRESSIVE is false, control statements are conservatively marked as | |
| 269 necessary. */ | |
| 270 | |
| 271 static void | |
| 272 mark_stmt_if_obviously_necessary (gimple stmt, bool aggressive) | |
| 273 { | |
| 274 tree lhs = NULL_TREE; | |
| 275 /* With non-call exceptions, we have to assume that all statements could | |
| 276 throw. If a statement may throw, it is inherently necessary. */ | |
| 277 if (flag_non_call_exceptions | |
| 278 && stmt_could_throw_p (stmt)) | |
| 279 { | |
| 280 mark_stmt_necessary (stmt, true); | |
| 281 return; | |
| 282 } | |
| 283 | |
| 284 /* Statements that are implicitly live. Most function calls, asm | |
| 285 and return statements are required. Labels and GIMPLE_BIND nodes | |
| 286 are kept because they are control flow, and we have no way of | |
| 287 knowing whether they can be removed. DCE can eliminate all the | |
| 288 other statements in a block, and CFG can then remove the block | |
| 289 and labels. */ | |
| 290 switch (gimple_code (stmt)) | |
| 291 { | |
| 292 case GIMPLE_PREDICT: | |
| 293 case GIMPLE_LABEL: | |
| 294 mark_stmt_necessary (stmt, false); | |
| 295 return; | |
| 296 | |
| 297 case GIMPLE_ASM: | |
| 298 case GIMPLE_RESX: | |
| 299 case GIMPLE_RETURN: | |
| 300 mark_stmt_necessary (stmt, true); | |
| 301 return; | |
| 302 | |
| 303 case GIMPLE_CALL: | |
| 304 /* Most, but not all function calls are required. Function calls that | |
| 305 produce no result and have no side effects (i.e. const pure | |
| 306 functions) are unnecessary. */ | |
| 307 if (gimple_has_side_effects (stmt)) | |
| 308 { | |
| 309 mark_stmt_necessary (stmt, true); | |
| 310 return; | |
| 311 } | |
| 312 if (!gimple_call_lhs (stmt)) | |
| 313 return; | |
| 314 lhs = gimple_call_lhs (stmt); | |
| 315 /* Fall through */ | |
| 316 | |
| 317 case GIMPLE_ASSIGN: | |
| 318 if (!lhs) | |
| 319 lhs = gimple_assign_lhs (stmt); | |
| 320 break; | |
| 321 | |
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322 case GIMPLE_DEBUG: |
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323 /* Debug temps without a value are not useful. ??? If we could |
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324 easily locate the debug temp bind stmt for a use thereof, |
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325 would could refrain from marking all debug temps here, and |
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326 mark them only if they're used. */ |
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327 if (gimple_debug_bind_has_value_p (stmt) |
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328 || TREE_CODE (gimple_debug_bind_get_var (stmt)) != DEBUG_EXPR_DECL) |
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329 mark_stmt_necessary (stmt, false); |
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330 return; |
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331 |
| 0 | 332 case GIMPLE_GOTO: |
| 333 gcc_assert (!simple_goto_p (stmt)); | |
| 334 mark_stmt_necessary (stmt, true); | |
| 335 return; | |
| 336 | |
| 337 case GIMPLE_COND: | |
| 338 gcc_assert (EDGE_COUNT (gimple_bb (stmt)->succs) == 2); | |
| 339 /* Fall through. */ | |
| 340 | |
| 341 case GIMPLE_SWITCH: | |
| 342 if (! aggressive) | |
| 343 mark_stmt_necessary (stmt, true); | |
| 344 break; | |
| 345 | |
| 346 default: | |
| 347 break; | |
| 348 } | |
| 349 | |
| 350 /* If the statement has volatile operands, it needs to be preserved. | |
| 351 Same for statements that can alter control flow in unpredictable | |
| 352 ways. */ | |
| 353 if (gimple_has_volatile_ops (stmt) || is_ctrl_altering_stmt (stmt)) | |
| 354 { | |
| 355 mark_stmt_necessary (stmt, true); | |
| 356 return; | |
| 357 } | |
| 358 | |
| 359 if (is_hidden_global_store (stmt)) | |
| 360 { | |
| 361 mark_stmt_necessary (stmt, true); | |
| 362 return; | |
| 363 } | |
| 364 | |
| 365 return; | |
| 366 } | |
| 367 | |
| 368 | |
| 369 /* Make corresponding control dependent edges necessary. We only | |
| 370 have to do this once for each basic block, so we clear the bitmap | |
|
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371 after we're done. |
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372 |
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373 When IGNORE_SELF it true, ignore BB from the list of control dependences. */ |
| 0 | 374 static void |
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375 mark_control_dependent_edges_necessary (basic_block bb, struct edge_list *el, bool ignore_self) |
| 0 | 376 { |
| 377 bitmap_iterator bi; | |
| 378 unsigned edge_number; | |
|
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379 bool skipped = false; |
| 0 | 380 |
| 381 gcc_assert (bb != EXIT_BLOCK_PTR); | |
| 382 | |
| 383 if (bb == ENTRY_BLOCK_PTR) | |
| 384 return; | |
| 385 | |
| 386 EXECUTE_IF_CONTROL_DEPENDENT (bi, bb->index, edge_number) | |
| 387 { | |
| 388 gimple stmt; | |
| 389 basic_block cd_bb = INDEX_EDGE_PRED_BB (el, edge_number); | |
| 390 | |
|
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391 if (ignore_self && cd_bb == bb) |
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392 { |
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393 skipped = true; |
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394 continue; |
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395 } |
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396 |
| 0 | 397 if (TEST_BIT (last_stmt_necessary, cd_bb->index)) |
| 398 continue; | |
| 399 SET_BIT (last_stmt_necessary, cd_bb->index); | |
|
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400 SET_BIT (bb_contains_live_stmts, cd_bb->index); |
| 0 | 401 |
| 402 stmt = last_stmt (cd_bb); | |
| 403 if (stmt && is_ctrl_stmt (stmt)) | |
| 404 mark_stmt_necessary (stmt, true); | |
| 405 } | |
|
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406 if (!skipped) |
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407 SET_BIT (visited_control_parents, bb->index); |
| 0 | 408 } |
| 409 | |
| 410 | |
| 411 /* Find obviously necessary statements. These are things like most function | |
| 412 calls, and stores to file level variables. | |
| 413 | |
| 414 If EL is NULL, control statements are conservatively marked as | |
| 415 necessary. Otherwise it contains the list of edges used by control | |
| 416 dependence analysis. */ | |
| 417 | |
| 418 static void | |
| 419 find_obviously_necessary_stmts (struct edge_list *el) | |
| 420 { | |
| 421 basic_block bb; | |
| 422 gimple_stmt_iterator gsi; | |
| 423 edge e; | |
| 424 gimple phi, stmt; | |
| 425 | |
| 426 FOR_EACH_BB (bb) | |
| 427 { | |
| 428 /* PHI nodes are never inherently necessary. */ | |
| 429 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
| 430 { | |
| 431 phi = gsi_stmt (gsi); | |
| 432 gimple_set_plf (phi, STMT_NECESSARY, false); | |
| 433 } | |
| 434 | |
| 435 /* Check all statements in the block. */ | |
| 436 for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi)) | |
| 437 { | |
| 438 stmt = gsi_stmt (gsi); | |
| 439 gimple_set_plf (stmt, STMT_NECESSARY, false); | |
| 440 mark_stmt_if_obviously_necessary (stmt, el != NULL); | |
| 441 } | |
| 442 } | |
| 443 | |
|
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444 /* Pure and const functions are finite and thus have no infinite loops in |
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445 them. */ |
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446 if ((TREE_READONLY (current_function_decl) |
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447 || DECL_PURE_P (current_function_decl)) |
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448 && !DECL_LOOPING_CONST_OR_PURE_P (current_function_decl)) |
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449 return; |
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450 |
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451 /* Prevent the empty possibly infinite loops from being removed. */ |
| 0 | 452 if (el) |
| 453 { | |
|
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454 loop_iterator li; |
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455 struct loop *loop; |
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456 scev_initialize (); |
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457 if (mark_irreducible_loops ()) |
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458 FOR_EACH_BB (bb) |
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459 { |
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460 edge_iterator ei; |
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461 FOR_EACH_EDGE (e, ei, bb->succs) |
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462 if ((e->flags & EDGE_DFS_BACK) |
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463 && (e->flags & EDGE_IRREDUCIBLE_LOOP)) |
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464 { |
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465 if (dump_file) |
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466 fprintf (dump_file, "Marking back edge of irreducible loop %i->%i\n", |
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467 e->src->index, e->dest->index); |
|
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468 mark_control_dependent_edges_necessary (e->dest, el, false); |
|
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469 } |
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470 } |
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471 |
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472 FOR_EACH_LOOP (li, loop, 0) |
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473 if (!finite_loop_p (loop)) |
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474 { |
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475 if (dump_file) |
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476 fprintf (dump_file, "can not prove finiteness of loop %i\n", loop->num); |
|
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477 mark_control_dependent_edges_necessary (loop->latch, el, false); |
|
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478 } |
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479 scev_finalize (); |
| 0 | 480 } |
| 481 } | |
| 482 | |
| 483 | |
|
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484 /* Return true if REF is based on an aliased base, otherwise false. */ |
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485 |
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486 static bool |
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487 ref_may_be_aliased (tree ref) |
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488 { |
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489 while (handled_component_p (ref)) |
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490 ref = TREE_OPERAND (ref, 0); |
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491 return !(DECL_P (ref) |
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492 && !may_be_aliased (ref)); |
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493 } |
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494 |
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495 static bitmap visited = NULL; |
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496 static unsigned int longest_chain = 0; |
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497 static unsigned int total_chain = 0; |
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498 static unsigned int nr_walks = 0; |
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499 static bool chain_ovfl = false; |
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500 |
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501 /* Worker for the walker that marks reaching definitions of REF, |
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502 which is based on a non-aliased decl, necessary. It returns |
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503 true whenever the defining statement of the current VDEF is |
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504 a kill for REF, as no dominating may-defs are necessary for REF |
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505 anymore. DATA points to the basic-block that contains the |
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506 stmt that refers to REF. */ |
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507 |
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508 static bool |
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509 mark_aliased_reaching_defs_necessary_1 (ao_ref *ref, tree vdef, void *data) |
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510 { |
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511 gimple def_stmt = SSA_NAME_DEF_STMT (vdef); |
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512 |
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513 /* All stmts we visit are necessary. */ |
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514 mark_operand_necessary (vdef); |
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515 |
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516 /* If the stmt lhs kills ref, then we can stop walking. */ |
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517 if (gimple_has_lhs (def_stmt) |
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518 && TREE_CODE (gimple_get_lhs (def_stmt)) != SSA_NAME) |
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519 { |
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520 tree base, lhs = gimple_get_lhs (def_stmt); |
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521 HOST_WIDE_INT size, offset, max_size; |
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522 ao_ref_base (ref); |
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523 base = get_ref_base_and_extent (lhs, &offset, &size, &max_size); |
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524 /* We can get MEM[symbol: sZ, index: D.8862_1] here, |
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525 so base == refd->base does not always hold. */ |
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526 if (base == ref->base) |
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527 { |
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528 /* For a must-alias check we need to be able to constrain |
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529 the accesses properly. */ |
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530 if (size != -1 && size == max_size |
|
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531 && ref->max_size != -1) |
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532 { |
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533 if (offset <= ref->offset |
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534 && offset + size >= ref->offset + ref->max_size) |
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535 return true; |
|
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536 } |
|
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537 /* Or they need to be exactly the same. */ |
|
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538 else if (ref->ref |
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539 /* Make sure there is no induction variable involved |
|
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540 in the references (gcc.c-torture/execute/pr42142.c). |
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541 The simplest way is to check if the kill dominates |
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542 the use. */ |
|
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543 && dominated_by_p (CDI_DOMINATORS, (basic_block) data, |
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544 gimple_bb (def_stmt)) |
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545 && operand_equal_p (ref->ref, lhs, 0)) |
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546 return true; |
|
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547 } |
|
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548 } |
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549 |
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550 /* Otherwise keep walking. */ |
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551 return false; |
|
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552 } |
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553 |
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554 static void |
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555 mark_aliased_reaching_defs_necessary (gimple stmt, tree ref) |
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556 { |
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557 unsigned int chain; |
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558 ao_ref refd; |
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559 gcc_assert (!chain_ovfl); |
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560 ao_ref_init (&refd, ref); |
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561 chain = walk_aliased_vdefs (&refd, gimple_vuse (stmt), |
|
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562 mark_aliased_reaching_defs_necessary_1, |
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563 gimple_bb (stmt), NULL); |
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564 if (chain > longest_chain) |
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565 longest_chain = chain; |
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566 total_chain += chain; |
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567 nr_walks++; |
|
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568 } |
|
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569 |
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parents:
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570 /* Worker for the walker that marks reaching definitions of REF, which |
|
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parents:
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571 is not based on a non-aliased decl. For simplicity we need to end |
|
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parents:
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572 up marking all may-defs necessary that are not based on a non-aliased |
|
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573 decl. The only job of this walker is to skip may-defs based on |
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574 a non-aliased decl. */ |
|
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575 |
|
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576 static bool |
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577 mark_all_reaching_defs_necessary_1 (ao_ref *ref ATTRIBUTE_UNUSED, |
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578 tree vdef, void *data ATTRIBUTE_UNUSED) |
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579 { |
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580 gimple def_stmt = SSA_NAME_DEF_STMT (vdef); |
|
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581 |
|
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582 /* We have to skip already visited (and thus necessary) statements |
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583 to make the chaining work after we dropped back to simple mode. */ |
|
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584 if (chain_ovfl |
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585 && TEST_BIT (processed, SSA_NAME_VERSION (vdef))) |
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586 { |
|
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587 gcc_assert (gimple_nop_p (def_stmt) |
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588 || gimple_plf (def_stmt, STMT_NECESSARY)); |
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589 return false; |
|
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590 } |
|
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|
591 |
|
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592 /* We want to skip stores to non-aliased variables. */ |
|
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593 if (!chain_ovfl |
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|
594 && gimple_assign_single_p (def_stmt)) |
|
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|
595 { |
|
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596 tree lhs = gimple_assign_lhs (def_stmt); |
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597 if (!ref_may_be_aliased (lhs)) |
|
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|
598 return false; |
|
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599 } |
|
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|
600 |
|
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parents:
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diff
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|
601 mark_operand_necessary (vdef); |
|
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|
602 |
|
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|
603 return false; |
|
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604 } |
|
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|
605 |
|
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changeset
|
606 static void |
|
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diff
changeset
|
607 mark_all_reaching_defs_necessary (gimple stmt) |
|
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608 { |
|
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609 walk_aliased_vdefs (NULL, gimple_vuse (stmt), |
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610 mark_all_reaching_defs_necessary_1, NULL, &visited); |
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611 } |
|
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|
612 |
|
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|
613 /* Return true for PHI nodes with one or identical arguments |
|
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changeset
|
614 can be removed. */ |
|
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changeset
|
615 static bool |
|
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changeset
|
616 degenerate_phi_p (gimple phi) |
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|
617 { |
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|
618 unsigned int i; |
|
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619 tree op = gimple_phi_arg_def (phi, 0); |
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620 for (i = 1; i < gimple_phi_num_args (phi); i++) |
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changeset
|
621 if (gimple_phi_arg_def (phi, i) != op) |
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622 return false; |
|
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|
623 return true; |
|
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|
624 } |
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|
625 |
| 0 | 626 /* Propagate necessity using the operands of necessary statements. |
| 627 Process the uses on each statement in the worklist, and add all | |
| 628 feeding statements which contribute to the calculation of this | |
|
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629 value to the worklist. |
| 0 | 630 |
| 631 In conservative mode, EL is NULL. */ | |
| 632 | |
| 633 static void | |
| 634 propagate_necessity (struct edge_list *el) | |
| 635 { | |
| 636 gimple stmt; | |
|
55
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|
637 bool aggressive = (el ? true : false); |
| 0 | 638 |
| 639 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 640 fprintf (dump_file, "\nProcessing worklist:\n"); | |
| 641 | |
| 642 while (VEC_length (gimple, worklist) > 0) | |
| 643 { | |
| 644 /* Take STMT from worklist. */ | |
| 645 stmt = VEC_pop (gimple, worklist); | |
| 646 | |
| 647 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 648 { | |
| 649 fprintf (dump_file, "processing: "); | |
| 650 print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); | |
| 651 fprintf (dump_file, "\n"); | |
| 652 } | |
| 653 | |
| 654 if (aggressive) | |
| 655 { | |
| 656 /* Mark the last statements of the basic blocks that the block | |
| 657 containing STMT is control dependent on, but only if we haven't | |
| 658 already done so. */ | |
| 659 basic_block bb = gimple_bb (stmt); | |
| 660 if (bb != ENTRY_BLOCK_PTR | |
| 661 && ! TEST_BIT (visited_control_parents, bb->index)) | |
|
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662 mark_control_dependent_edges_necessary (bb, el, false); |
| 0 | 663 } |
| 664 | |
|
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665 if (gimple_code (stmt) == GIMPLE_PHI |
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666 /* We do not process virtual PHI nodes nor do we track their |
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667 necessity. */ |
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668 && is_gimple_reg (gimple_phi_result (stmt))) |
| 0 | 669 { |
| 670 /* PHI nodes are somewhat special in that each PHI alternative has | |
| 671 data and control dependencies. All the statements feeding the | |
| 672 PHI node's arguments are always necessary. In aggressive mode, | |
| 673 we also consider the control dependent edges leading to the | |
| 674 predecessor block associated with each PHI alternative as | |
| 675 necessary. */ | |
| 676 size_t k; | |
| 677 | |
| 678 for (k = 0; k < gimple_phi_num_args (stmt); k++) | |
| 679 { | |
| 680 tree arg = PHI_ARG_DEF (stmt, k); | |
| 681 if (TREE_CODE (arg) == SSA_NAME) | |
| 682 mark_operand_necessary (arg); | |
| 683 } | |
| 684 | |
|
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685 /* For PHI operands it matters from where the control flow arrives |
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686 to the BB. Consider the following example: |
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687 |
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688 a=exp1; |
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689 b=exp2; |
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690 if (test) |
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691 ; |
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692 else |
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693 ; |
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694 c=PHI(a,b) |
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695 |
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696 We need to mark control dependence of the empty basic blocks, since they |
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697 contains computation of PHI operands. |
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698 |
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699 Doing so is too restrictive in the case the predecestor block is in |
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700 the loop. Consider: |
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701 |
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702 if (b) |
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703 { |
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704 int i; |
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705 for (i = 0; i<1000; ++i) |
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706 ; |
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707 j = 0; |
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708 } |
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709 return j; |
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710 |
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711 There is PHI for J in the BB containing return statement. |
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712 In this case the control dependence of predecestor block (that is |
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713 within the empty loop) also contains the block determining number |
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714 of iterations of the block that would prevent removing of empty |
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715 loop in this case. |
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716 |
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717 This scenario can be avoided by splitting critical edges. |
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718 To save the critical edge splitting pass we identify how the control |
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719 dependence would look like if the edge was split. |
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720 |
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721 Consider the modified CFG created from current CFG by splitting |
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722 edge B->C. In the postdominance tree of modified CFG, C' is |
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723 always child of C. There are two cases how chlids of C' can look |
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724 like: |
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725 |
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726 1) C' is leaf |
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727 |
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728 In this case the only basic block C' is control dependent on is B. |
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729 |
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730 2) C' has single child that is B |
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731 |
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732 In this case control dependence of C' is same as control |
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733 dependence of B in original CFG except for block B itself. |
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734 (since C' postdominate B in modified CFG) |
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735 |
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|
736 Now how to decide what case happens? There are two basic options: |
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737 |
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738 a) C postdominate B. Then C immediately postdominate B and |
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739 case 2 happens iff there is no other way from B to C except |
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740 the edge B->C. |
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741 |
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742 There is other way from B to C iff there is succesor of B that |
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743 is not postdominated by B. Testing this condition is somewhat |
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744 expensive, because we need to iterate all succesors of B. |
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745 We are safe to assume that this does not happen: we will mark B |
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746 as needed when processing the other path from B to C that is |
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747 conrol dependent on B and marking control dependencies of B |
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748 itself is harmless because they will be processed anyway after |
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749 processing control statement in B. |
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750 |
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751 b) C does not postdominate B. Always case 1 happens since there is |
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752 path from C to exit that does not go through B and thus also C'. */ |
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753 |
|
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754 if (aggressive && !degenerate_phi_p (stmt)) |
| 0 | 755 { |
| 756 for (k = 0; k < gimple_phi_num_args (stmt); k++) | |
| 757 { | |
| 758 basic_block arg_bb = gimple_phi_arg_edge (stmt, k)->src; | |
|
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759 |
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760 if (gimple_bb (stmt) |
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761 != get_immediate_dominator (CDI_POST_DOMINATORS, arg_bb)) |
| 0 | 762 { |
|
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763 if (!TEST_BIT (last_stmt_necessary, arg_bb->index)) |
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764 { |
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765 gimple stmt2; |
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766 SET_BIT (last_stmt_necessary, arg_bb->index); |
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767 SET_BIT (bb_contains_live_stmts, arg_bb->index); |
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|
768 |
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769 stmt2 = last_stmt (arg_bb); |
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770 if (stmt2 && is_ctrl_stmt (stmt2)) |
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771 mark_stmt_necessary (stmt2, true); |
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772 } |
| 0 | 773 } |
|
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774 else if (arg_bb != ENTRY_BLOCK_PTR |
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775 && ! TEST_BIT (visited_control_parents, arg_bb->index)) |
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776 mark_control_dependent_edges_necessary (arg_bb, el, true); |
| 0 | 777 } |
| 778 } | |
| 779 } | |
| 780 else | |
| 781 { | |
| 782 /* Propagate through the operands. Examine all the USE, VUSE and | |
|
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783 VDEF operands in this statement. Mark all the statements |
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784 which feed this statement's uses as necessary. */ |
| 0 | 785 ssa_op_iter iter; |
| 786 tree use; | |
| 787 | |
|
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|
788 FOR_EACH_SSA_TREE_OPERAND (use, stmt, iter, SSA_OP_USE) |
| 0 | 789 mark_operand_necessary (use); |
|
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ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
790 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
791 use = gimple_vuse (stmt); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
792 if (!use) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
793 continue; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
794 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
795 /* If we dropped to simple mode make all immediately |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
796 reachable definitions necessary. */ |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
797 if (chain_ovfl) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
798 { |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
799 mark_all_reaching_defs_necessary (stmt); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
800 continue; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
801 } |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
802 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
803 /* For statements that may load from memory (have a VUSE) we |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
804 have to mark all reaching (may-)definitions as necessary. |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
805 We partition this task into two cases: |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
806 1) explicit loads based on decls that are not aliased |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
807 2) implicit loads (like calls) and explicit loads not |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
808 based on decls that are not aliased (like indirect |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
809 references or loads from globals) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
810 For 1) we mark all reaching may-defs as necessary, stopping |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
811 at dominating kills. For 2) we want to mark all dominating |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
812 references necessary, but non-aliased ones which we handle |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
813 in 1). By keeping a global visited bitmap for references |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
814 we walk for 2) we avoid quadratic behavior for those. */ |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
815 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
816 if (is_gimple_call (stmt)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
817 { |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
818 tree callee = gimple_call_fndecl (stmt); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
819 unsigned i; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
820 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
821 /* Calls to functions that are merely acting as barriers |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
822 or that only store to memory do not make any previous |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
823 stores necessary. */ |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
824 if (callee != NULL_TREE |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
825 && DECL_BUILT_IN_CLASS (callee) == BUILT_IN_NORMAL |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
826 && (DECL_FUNCTION_CODE (callee) == BUILT_IN_MEMSET |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
827 || DECL_FUNCTION_CODE (callee) == BUILT_IN_MALLOC |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
828 || DECL_FUNCTION_CODE (callee) == BUILT_IN_FREE)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
829 continue; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
830 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
831 /* Calls implicitly load from memory, their arguments |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
832 in addition may explicitly perform memory loads. */ |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
833 mark_all_reaching_defs_necessary (stmt); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
834 for (i = 0; i < gimple_call_num_args (stmt); ++i) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
835 { |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
836 tree arg = gimple_call_arg (stmt, i); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
837 if (TREE_CODE (arg) == SSA_NAME |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
838 || is_gimple_min_invariant (arg)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
839 continue; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
840 if (!ref_may_be_aliased (arg)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
841 mark_aliased_reaching_defs_necessary (stmt, arg); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
842 } |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
843 } |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
844 else if (gimple_assign_single_p (stmt)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
845 { |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
846 tree rhs; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
847 bool rhs_aliased = false; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
848 /* If this is a load mark things necessary. */ |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
849 rhs = gimple_assign_rhs1 (stmt); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
850 if (TREE_CODE (rhs) != SSA_NAME |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
851 && !is_gimple_min_invariant (rhs)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
852 { |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
853 if (!ref_may_be_aliased (rhs)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
854 mark_aliased_reaching_defs_necessary (stmt, rhs); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
855 else |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
856 rhs_aliased = true; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
857 } |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
858 if (rhs_aliased) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
859 mark_all_reaching_defs_necessary (stmt); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
860 } |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
861 else if (gimple_code (stmt) == GIMPLE_RETURN) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
862 { |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
863 tree rhs = gimple_return_retval (stmt); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
864 /* A return statement may perform a load. */ |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
865 if (TREE_CODE (rhs) != SSA_NAME |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
866 && !is_gimple_min_invariant (rhs)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
867 { |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
868 if (!ref_may_be_aliased (rhs)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
869 mark_aliased_reaching_defs_necessary (stmt, rhs); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
870 else |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
871 mark_all_reaching_defs_necessary (stmt); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
872 } |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
873 } |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
874 else if (gimple_code (stmt) == GIMPLE_ASM) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
875 { |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
876 unsigned i; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
877 mark_all_reaching_defs_necessary (stmt); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
878 /* Inputs may perform loads. */ |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
879 for (i = 0; i < gimple_asm_ninputs (stmt); ++i) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
880 { |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
881 tree op = TREE_VALUE (gimple_asm_input_op (stmt, i)); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
882 if (TREE_CODE (op) != SSA_NAME |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
883 && !is_gimple_min_invariant (op) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
884 && !ref_may_be_aliased (op)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
885 mark_aliased_reaching_defs_necessary (stmt, op); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
886 } |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
887 } |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
888 else |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
889 gcc_unreachable (); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
890 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
891 /* If we over-used our alias oracle budget drop to simple |
|
77e2b8dfacca
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parents:
0
diff
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|
892 mode. The cost metric allows quadratic behavior |
|
77e2b8dfacca
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parents:
0
diff
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|
893 (number of uses times number of may-defs queries) up to |
|
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parents:
0
diff
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|
894 a constant maximal number of queries and after that falls back to |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
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parents:
0
diff
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|
895 super-linear complexity. */ |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
896 if (/* Constant but quadratic for small functions. */ |
|
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parents:
0
diff
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|
897 total_chain > 128 * 128 |
|
77e2b8dfacca
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0
diff
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|
898 /* Linear in the number of may-defs. */ |
|
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parents:
0
diff
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|
899 && total_chain > 32 * longest_chain |
|
77e2b8dfacca
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parents:
0
diff
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|
900 /* Linear in the number of uses. */ |
|
77e2b8dfacca
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parents:
0
diff
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|
901 && total_chain > nr_walks * 32) |
|
77e2b8dfacca
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parents:
0
diff
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|
902 { |
|
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parents:
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diff
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|
903 chain_ovfl = true; |
|
77e2b8dfacca
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ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
904 if (visited) |
|
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update it from 4.4.3 to 4.5.0
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parents:
0
diff
changeset
|
905 bitmap_clear (visited); |
|
77e2b8dfacca
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parents:
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diff
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|
906 } |
| 0 | 907 } |
| 908 } | |
| 909 } | |
| 910 | |
|
55
77e2b8dfacca
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parents:
0
diff
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|
911 /* Replace all uses of result of PHI by underlying variable and mark it |
|
77e2b8dfacca
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parents:
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diff
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|
912 for renaming. */ |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
913 |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
914 void |
|
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parents:
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diff
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|
915 mark_virtual_phi_result_for_renaming (gimple phi) |
|
77e2b8dfacca
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diff
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|
916 { |
|
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parents:
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diff
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|
917 bool used = false; |
|
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parents:
0
diff
changeset
|
918 imm_use_iterator iter; |
|
77e2b8dfacca
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parents:
0
diff
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|
919 use_operand_p use_p; |
|
77e2b8dfacca
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parents:
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diff
changeset
|
920 gimple stmt; |
|
77e2b8dfacca
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parents:
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diff
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|
921 tree result_ssa, result_var; |
|
77e2b8dfacca
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parents:
0
diff
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|
922 |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
923 if (dump_file && (dump_flags & TDF_DETAILS)) |
|
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parents:
0
diff
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|
924 { |
|
77e2b8dfacca
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parents:
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diff
changeset
|
925 fprintf (dump_file, "Marking result for renaming : "); |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
926 print_gimple_stmt (dump_file, phi, 0, TDF_SLIM); |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
927 fprintf (dump_file, "\n"); |
|
77e2b8dfacca
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parents:
0
diff
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|
928 } |
|
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parents:
0
diff
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|
929 |
|
77e2b8dfacca
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parents:
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diff
changeset
|
930 result_ssa = gimple_phi_result (phi); |
|
77e2b8dfacca
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parents:
0
diff
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|
931 result_var = SSA_NAME_VAR (result_ssa); |
|
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parents:
0
diff
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|
932 FOR_EACH_IMM_USE_STMT (stmt, iter, result_ssa) |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
933 { |
|
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parents:
0
diff
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|
934 FOR_EACH_IMM_USE_ON_STMT (use_p, iter) |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
935 SET_USE (use_p, result_var); |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
936 update_stmt (stmt); |
|
77e2b8dfacca
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parents:
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diff
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|
937 used = true; |
|
77e2b8dfacca
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parents:
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diff
changeset
|
938 } |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
939 if (used) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
940 mark_sym_for_renaming (result_var); |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
941 } |
| 0 | 942 |
| 943 /* Remove dead PHI nodes from block BB. */ | |
| 944 | |
| 945 static bool | |
| 946 remove_dead_phis (basic_block bb) | |
| 947 { | |
| 948 bool something_changed = false; | |
| 949 gimple_seq phis; | |
| 950 gimple phi; | |
| 951 gimple_stmt_iterator gsi; | |
| 952 phis = phi_nodes (bb); | |
| 953 | |
| 954 for (gsi = gsi_start (phis); !gsi_end_p (gsi);) | |
| 955 { | |
| 956 stats.total_phis++; | |
| 957 phi = gsi_stmt (gsi); | |
| 958 | |
|
55
77e2b8dfacca
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parents:
0
diff
changeset
|
959 /* We do not track necessity of virtual PHI nodes. Instead do |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
960 very simple dead PHI removal here. */ |
|
77e2b8dfacca
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ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
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diff
changeset
|
961 if (!is_gimple_reg (gimple_phi_result (phi))) |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
962 { |
|
77e2b8dfacca
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ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
963 /* Virtual PHI nodes with one or identical arguments |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
964 can be removed. */ |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
965 if (degenerate_phi_p (phi)) |
|
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parents:
0
diff
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|
966 { |
|
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parents:
0
diff
changeset
|
967 tree vdef = gimple_phi_result (phi); |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
968 tree vuse = gimple_phi_arg_def (phi, 0); |
|
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parents:
0
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changeset
|
969 |
|
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update it from 4.4.3 to 4.5.0
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parents:
0
diff
changeset
|
970 use_operand_p use_p; |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
971 imm_use_iterator iter; |
|
77e2b8dfacca
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parents:
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diff
changeset
|
972 gimple use_stmt; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
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diff
changeset
|
973 FOR_EACH_IMM_USE_STMT (use_stmt, iter, vdef) |
|
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parents:
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changeset
|
974 FOR_EACH_IMM_USE_ON_STMT (use_p, iter) |
|
77e2b8dfacca
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parents:
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diff
changeset
|
975 SET_USE (use_p, vuse); |
|
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parents:
0
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changeset
|
976 if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (vdef) |
|
77e2b8dfacca
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parents:
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changeset
|
977 && TREE_CODE (vuse) == SSA_NAME) |
|
77e2b8dfacca
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parents:
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diff
changeset
|
978 SSA_NAME_OCCURS_IN_ABNORMAL_PHI (vuse) = 1; |
|
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0
diff
changeset
|
979 } |
|
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parents:
0
diff
changeset
|
980 else |
|
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parents:
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diff
changeset
|
981 gimple_set_plf (phi, STMT_NECESSARY, true); |
|
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parents:
0
diff
changeset
|
982 } |
|
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parents:
0
diff
changeset
|
983 |
| 0 | 984 if (!gimple_plf (phi, STMT_NECESSARY)) |
| 985 { | |
| 986 something_changed = true; | |
| 987 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 988 { | |
| 989 fprintf (dump_file, "Deleting : "); | |
| 990 print_gimple_stmt (dump_file, phi, 0, TDF_SLIM); | |
| 991 fprintf (dump_file, "\n"); | |
| 992 } | |
| 993 | |
| 994 remove_phi_node (&gsi, true); | |
| 995 stats.removed_phis++; | |
|
55
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changeset
|
996 continue; |
| 0 | 997 } |
|
55
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parents:
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changeset
|
998 |
|
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parents:
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diff
changeset
|
999 gsi_next (&gsi); |
| 0 | 1000 } |
| 1001 return something_changed; | |
| 1002 } | |
| 1003 | |
|
55
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diff
changeset
|
1004 /* Forward edge E to respective POST_DOM_BB and update PHIs. */ |
|
77e2b8dfacca
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changeset
|
1005 |
|
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diff
changeset
|
1006 static edge |
|
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parents:
0
diff
changeset
|
1007 forward_edge_to_pdom (edge e, basic_block post_dom_bb) |
|
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changeset
|
1008 { |
|
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0
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changeset
|
1009 gimple_stmt_iterator gsi; |
|
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changeset
|
1010 edge e2 = NULL; |
|
77e2b8dfacca
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diff
changeset
|
1011 edge_iterator ei; |
|
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0
diff
changeset
|
1012 |
|
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changeset
|
1013 if (dump_file && (dump_flags & TDF_DETAILS)) |
|
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changeset
|
1014 fprintf (dump_file, "Redirecting edge %i->%i to %i\n", e->src->index, |
|
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parents:
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diff
changeset
|
1015 e->dest->index, post_dom_bb->index); |
|
77e2b8dfacca
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parents:
0
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changeset
|
1016 |
|
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0
diff
changeset
|
1017 e2 = redirect_edge_and_branch (e, post_dom_bb); |
|
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|
1018 cfg_altered = true; |
|
77e2b8dfacca
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changeset
|
1019 |
|
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|
1020 /* If edge was already around, no updating is neccesary. */ |
|
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|
1021 if (e2 != e) |
|
77e2b8dfacca
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changeset
|
1022 return e2; |
|
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|
1023 |
|
63
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55
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|
1024 if (!gimple_seq_empty_p (phi_nodes (post_dom_bb))) |
|
55
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1025 { |
|
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1026 /* We are sure that for every live PHI we are seeing control dependent BB. |
|
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1027 This means that we can pick any edge to duplicate PHI args from. */ |
|
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1028 FOR_EACH_EDGE (e2, ei, post_dom_bb->preds) |
|
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1029 if (e2 != e) |
|
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1030 break; |
|
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1031 for (gsi = gsi_start_phis (post_dom_bb); !gsi_end_p (gsi);) |
|
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1032 { |
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1033 gimple phi = gsi_stmt (gsi); |
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1034 tree op; |
|
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1035 source_location locus; |
|
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1036 |
|
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1037 /* PHIs for virtuals have no control dependency relation on them. |
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1038 We are lost here and must force renaming of the symbol. */ |
|
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1039 if (!is_gimple_reg (gimple_phi_result (phi))) |
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1040 { |
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1041 mark_virtual_phi_result_for_renaming (phi); |
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1042 remove_phi_node (&gsi, true); |
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1043 continue; |
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1044 } |
|
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1045 |
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1046 /* Dead PHI do not imply control dependency. */ |
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1047 if (!gimple_plf (phi, STMT_NECESSARY)) |
|
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1048 { |
|
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1049 gsi_next (&gsi); |
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1050 continue; |
|
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1051 } |
|
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1052 |
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1053 op = gimple_phi_arg_def (phi, e2->dest_idx); |
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1054 locus = gimple_phi_arg_location (phi, e2->dest_idx); |
|
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1055 add_phi_arg (phi, op, e, locus); |
|
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1056 /* The resulting PHI if not dead can only be degenerate. */ |
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1057 gcc_assert (degenerate_phi_p (phi)); |
|
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1058 gsi_next (&gsi); |
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1059 } |
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1060 } |
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1061 return e; |
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1062 } |
| 0 | 1063 |
| 1064 /* Remove dead statement pointed to by iterator I. Receives the basic block BB | |
| 1065 containing I so that we don't have to look it up. */ | |
| 1066 | |
| 1067 static void | |
| 1068 remove_dead_stmt (gimple_stmt_iterator *i, basic_block bb) | |
| 1069 { | |
| 1070 gimple stmt = gsi_stmt (*i); | |
| 1071 | |
| 1072 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 1073 { | |
| 1074 fprintf (dump_file, "Deleting : "); | |
| 1075 print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); | |
| 1076 fprintf (dump_file, "\n"); | |
| 1077 } | |
| 1078 | |
| 1079 stats.removed++; | |
| 1080 | |
| 1081 /* If we have determined that a conditional branch statement contributes | |
| 1082 nothing to the program, then we not only remove it, but we also change | |
| 1083 the flow graph so that the current block will simply fall-thru to its | |
| 1084 immediate post-dominator. The blocks we are circumventing will be | |
| 1085 removed by cleanup_tree_cfg if this change in the flow graph makes them | |
| 1086 unreachable. */ | |
| 1087 if (is_ctrl_stmt (stmt)) | |
| 1088 { | |
| 1089 basic_block post_dom_bb; | |
|
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1090 edge e, e2; |
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1091 edge_iterator ei; |
| 0 | 1092 |
|
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1093 post_dom_bb = get_immediate_dominator (CDI_POST_DOMINATORS, bb); |
| 0 | 1094 |
|
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1095 e = find_edge (bb, post_dom_bb); |
| 0 | 1096 |
|
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1097 /* If edge is already there, try to use it. This avoids need to update |
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1098 PHI nodes. Also watch for cases where post dominator does not exists |
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1099 or is exit block. These can happen for infinite loops as we create |
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1100 fake edges in the dominator tree. */ |
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1101 if (e) |
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1102 ; |
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1103 else if (! post_dom_bb || post_dom_bb == EXIT_BLOCK_PTR) |
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1104 e = EDGE_SUCC (bb, 0); |
| 0 | 1105 else |
|
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1106 e = forward_edge_to_pdom (EDGE_SUCC (bb, 0), post_dom_bb); |
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1107 gcc_assert (e); |
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1108 e->probability = REG_BR_PROB_BASE; |
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1109 e->count = bb->count; |
| 0 | 1110 |
| 1111 /* The edge is no longer associated with a conditional, so it does | |
| 1112 not have TRUE/FALSE flags. */ | |
|
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1113 e->flags &= ~(EDGE_TRUE_VALUE | EDGE_FALSE_VALUE); |
| 0 | 1114 |
| 1115 /* The lone outgoing edge from BB will be a fallthru edge. */ | |
|
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1116 e->flags |= EDGE_FALLTHRU; |
| 0 | 1117 |
|
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1118 /* Remove the remaining outgoing edges. */ |
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1119 for (ei = ei_start (bb->succs); (e2 = ei_safe_edge (ei)); ) |
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1120 if (e != e2) |
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1121 { |
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1122 cfg_altered = true; |
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1123 remove_edge (e2); |
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1124 } |
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1125 else |
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1126 ei_next (&ei); |
| 0 | 1127 } |
|
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1128 |
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1129 unlink_stmt_vdef (stmt); |
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1130 gsi_remove (i, true); |
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1131 release_defs (stmt); |
| 0 | 1132 } |
| 1133 | |
| 1134 /* Eliminate unnecessary statements. Any instruction not marked as necessary | |
| 1135 contributes nothing to the program, and can be deleted. */ | |
| 1136 | |
| 1137 static bool | |
| 1138 eliminate_unnecessary_stmts (void) | |
| 1139 { | |
| 1140 bool something_changed = false; | |
| 1141 basic_block bb; | |
|
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1142 gimple_stmt_iterator gsi, psi; |
| 0 | 1143 gimple stmt; |
| 1144 tree call; | |
|
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1145 VEC (basic_block, heap) *h; |
| 0 | 1146 |
| 1147 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 1148 fprintf (dump_file, "\nEliminating unnecessary statements:\n"); | |
| 1149 | |
| 1150 clear_special_calls (); | |
|
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1151 |
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1152 /* Walking basic blocks and statements in reverse order avoids |
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1153 releasing SSA names before any other DEFs that refer to them are |
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1154 released. This helps avoid loss of debug information, as we get |
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1155 a chance to propagate all RHSs of removed SSAs into debug uses, |
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1156 rather than only the latest ones. E.g., consider: |
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1157 |
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1158 x_3 = y_1 + z_2; |
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1159 a_5 = x_3 - b_4; |
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1160 # DEBUG a => a_5 |
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1161 |
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1162 If we were to release x_3 before a_5, when we reached a_5 and |
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1163 tried to substitute it into the debug stmt, we'd see x_3 there, |
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1164 but x_3's DEF, type, etc would have already been disconnected. |
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1165 By going backwards, the debug stmt first changes to: |
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1166 |
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1167 # DEBUG a => x_3 - b_4 |
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1168 |
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1169 and then to: |
|
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diff
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|
1170 |
|
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diff
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|
1171 # DEBUG a => y_1 + z_2 - b_4 |
|
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diff
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|
1172 |
|
77e2b8dfacca
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diff
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|
1173 as desired. */ |
|
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parents:
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diff
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|
1174 gcc_assert (dom_info_available_p (CDI_DOMINATORS)); |
|
77e2b8dfacca
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diff
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|
1175 h = get_all_dominated_blocks (CDI_DOMINATORS, single_succ (ENTRY_BLOCK_PTR)); |
|
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parents:
0
diff
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|
1176 |
|
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update it from 4.4.3 to 4.5.0
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parents:
0
diff
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|
1177 while (VEC_length (basic_block, h)) |
| 0 | 1178 { |
|
55
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parents:
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diff
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|
1179 bb = VEC_pop (basic_block, h); |
| 0 | 1180 |
| 1181 /* Remove dead statements. */ | |
|
55
77e2b8dfacca
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parents:
0
diff
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|
1182 for (gsi = gsi_last_bb (bb); !gsi_end_p (gsi); gsi = psi) |
| 0 | 1183 { |
| 1184 stmt = gsi_stmt (gsi); | |
| 1185 | |
|
55
77e2b8dfacca
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parents:
0
diff
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|
1186 psi = gsi; |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
1187 gsi_prev (&psi); |
|
77e2b8dfacca
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parents:
0
diff
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|
1188 |
| 0 | 1189 stats.total++; |
| 1190 | |
| 1191 /* If GSI is not necessary then remove it. */ | |
| 1192 if (!gimple_plf (stmt, STMT_NECESSARY)) | |
| 1193 { | |
|
55
77e2b8dfacca
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parents:
0
diff
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|
1194 if (!is_gimple_debug (stmt)) |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
1195 something_changed = true; |
| 0 | 1196 remove_dead_stmt (&gsi, bb); |
| 1197 } | |
| 1198 else if (is_gimple_call (stmt)) | |
| 1199 { | |
| 1200 call = gimple_call_fndecl (stmt); | |
| 1201 if (call) | |
| 1202 { | |
| 1203 tree name; | |
| 1204 | |
| 1205 /* When LHS of var = call (); is dead, simplify it into | |
| 1206 call (); saving one operand. */ | |
| 1207 name = gimple_call_lhs (stmt); | |
| 1208 if (name && TREE_CODE (name) == SSA_NAME | |
| 1209 && !TEST_BIT (processed, SSA_NAME_VERSION (name))) | |
| 1210 { | |
| 1211 something_changed = true; | |
| 1212 if (dump_file && (dump_flags & TDF_DETAILS)) | |
| 1213 { | |
| 1214 fprintf (dump_file, "Deleting LHS of call: "); | |
| 1215 print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM); | |
| 1216 fprintf (dump_file, "\n"); | |
| 1217 } | |
|
55
77e2b8dfacca
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parents:
0
diff
changeset
|
1218 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
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parents:
0
diff
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|
1219 gimple_call_set_lhs (stmt, NULL_TREE); |
|
77e2b8dfacca
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parents:
0
diff
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|
1220 maybe_clean_or_replace_eh_stmt (stmt, stmt); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
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parents:
0
diff
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|
1221 update_stmt (stmt); |
| 0 | 1222 release_ssa_name (name); |
| 1223 } | |
| 1224 notice_special_calls (stmt); | |
| 1225 } | |
| 1226 } | |
| 1227 } | |
| 1228 } | |
| 1229 | |
|
55
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update it from 4.4.3 to 4.5.0
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parents:
0
diff
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|
1230 VEC_free (basic_block, heap, h); |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
1231 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1232 /* Since we don't track liveness of virtual PHI nodes, it is possible that we |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1233 rendered some PHI nodes unreachable while they are still in use. |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
1234 Mark them for renaming. */ |
|
77e2b8dfacca
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parents:
0
diff
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|
1235 if (cfg_altered) |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
1236 { |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
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parents:
0
diff
changeset
|
1237 basic_block prev_bb; |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
1238 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
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parents:
0
diff
changeset
|
1239 find_unreachable_blocks (); |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
1240 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
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parents:
0
diff
changeset
|
1241 /* Delete all unreachable basic blocks in reverse dominator order. */ |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1242 for (bb = EXIT_BLOCK_PTR->prev_bb; bb != ENTRY_BLOCK_PTR; bb = prev_bb) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1243 { |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
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parents:
0
diff
changeset
|
1244 prev_bb = bb->prev_bb; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
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parents:
0
diff
changeset
|
1245 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1246 if (!TEST_BIT (bb_contains_live_stmts, bb->index) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
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parents:
0
diff
changeset
|
1247 || !(bb->flags & BB_REACHABLE)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1248 { |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1249 for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1250 if (!is_gimple_reg (gimple_phi_result (gsi_stmt (gsi)))) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1251 { |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1252 bool found = false; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1253 imm_use_iterator iter; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1254 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1255 FOR_EACH_IMM_USE_STMT (stmt, iter, gimple_phi_result (gsi_stmt (gsi))) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1256 { |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1257 if (!(gimple_bb (stmt)->flags & BB_REACHABLE)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1258 continue; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1259 if (gimple_code (stmt) == GIMPLE_PHI |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1260 || gimple_plf (stmt, STMT_NECESSARY)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1261 { |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1262 found = true; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1263 BREAK_FROM_IMM_USE_STMT (iter); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1264 } |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1265 } |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1266 if (found) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1267 mark_virtual_phi_result_for_renaming (gsi_stmt (gsi)); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1268 } |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1269 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1270 if (!(bb->flags & BB_REACHABLE)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1271 { |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1272 /* Speed up the removal of blocks that don't |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1273 dominate others. Walking backwards, this should |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1274 be the common case. ??? Do we need to recompute |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1275 dominators because of cfg_altered? */ |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1276 if (!MAY_HAVE_DEBUG_STMTS |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1277 || !first_dom_son (CDI_DOMINATORS, bb)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1278 delete_basic_block (bb); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1279 else |
|
77e2b8dfacca
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ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1280 { |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1281 h = get_all_dominated_blocks (CDI_DOMINATORS, bb); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1282 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1283 while (VEC_length (basic_block, h)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1284 { |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1285 bb = VEC_pop (basic_block, h); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1286 prev_bb = bb->prev_bb; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1287 /* Rearrangements to the CFG may have failed |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1288 to update the dominators tree, so that |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1289 formerly-dominated blocks are now |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1290 otherwise reachable. */ |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1291 if (!!(bb->flags & BB_REACHABLE)) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1292 continue; |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1293 delete_basic_block (bb); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1294 } |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1295 |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1296 VEC_free (basic_block, heap, h); |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1297 } |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
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parents:
0
diff
changeset
|
1298 } |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
1299 } |
|
77e2b8dfacca
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ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1300 } |
|
77e2b8dfacca
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parents:
0
diff
changeset
|
1301 } |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1302 FOR_EACH_BB (bb) |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1303 { |
|
77e2b8dfacca
update it from 4.4.3 to 4.5.0
ryoma <e075725@ie.u-ryukyu.ac.jp>
parents:
0
diff
changeset
|
1304 /* Remove dead PHI nodes. */ |
|
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1305 something_changed |= remove_dead_phis (bb); |
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1306 } |
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1307 |
| 0 | 1308 return something_changed; |
| 1309 } | |
| 1310 | |
| 1311 | |
| 1312 /* Print out removed statement statistics. */ | |
| 1313 | |
| 1314 static void | |
| 1315 print_stats (void) | |
| 1316 { | |
| 1317 float percg; | |
| 1318 | |
| 1319 percg = ((float) stats.removed / (float) stats.total) * 100; | |
| 1320 fprintf (dump_file, "Removed %d of %d statements (%d%%)\n", | |
| 1321 stats.removed, stats.total, (int) percg); | |
| 1322 | |
| 1323 if (stats.total_phis == 0) | |
| 1324 percg = 0; | |
| 1325 else | |
| 1326 percg = ((float) stats.removed_phis / (float) stats.total_phis) * 100; | |
| 1327 | |
| 1328 fprintf (dump_file, "Removed %d of %d PHI nodes (%d%%)\n", | |
| 1329 stats.removed_phis, stats.total_phis, (int) percg); | |
| 1330 } | |
| 1331 | |
| 1332 /* Initialization for this pass. Set up the used data structures. */ | |
| 1333 | |
| 1334 static void | |
| 1335 tree_dce_init (bool aggressive) | |
| 1336 { | |
| 1337 memset ((void *) &stats, 0, sizeof (stats)); | |
| 1338 | |
| 1339 if (aggressive) | |
| 1340 { | |
| 1341 int i; | |
| 1342 | |
| 1343 control_dependence_map = XNEWVEC (bitmap, last_basic_block); | |
| 1344 for (i = 0; i < last_basic_block; ++i) | |
| 1345 control_dependence_map[i] = BITMAP_ALLOC (NULL); | |
| 1346 | |
| 1347 last_stmt_necessary = sbitmap_alloc (last_basic_block); | |
| 1348 sbitmap_zero (last_stmt_necessary); | |
|
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1349 bb_contains_live_stmts = sbitmap_alloc (last_basic_block); |
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1350 sbitmap_zero (bb_contains_live_stmts); |
| 0 | 1351 } |
| 1352 | |
| 1353 processed = sbitmap_alloc (num_ssa_names + 1); | |
| 1354 sbitmap_zero (processed); | |
| 1355 | |
| 1356 worklist = VEC_alloc (gimple, heap, 64); | |
| 1357 cfg_altered = false; | |
| 1358 } | |
| 1359 | |
| 1360 /* Cleanup after this pass. */ | |
| 1361 | |
| 1362 static void | |
| 1363 tree_dce_done (bool aggressive) | |
| 1364 { | |
| 1365 if (aggressive) | |
| 1366 { | |
| 1367 int i; | |
| 1368 | |
| 1369 for (i = 0; i < last_basic_block; ++i) | |
| 1370 BITMAP_FREE (control_dependence_map[i]); | |
| 1371 free (control_dependence_map); | |
| 1372 | |
| 1373 sbitmap_free (visited_control_parents); | |
| 1374 sbitmap_free (last_stmt_necessary); | |
|
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1375 sbitmap_free (bb_contains_live_stmts); |
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1376 bb_contains_live_stmts = NULL; |
| 0 | 1377 } |
| 1378 | |
| 1379 sbitmap_free (processed); | |
| 1380 | |
| 1381 VEC_free (gimple, heap, worklist); | |
| 1382 } | |
| 1383 | |
| 1384 /* Main routine to eliminate dead code. | |
| 1385 | |
| 1386 AGGRESSIVE controls the aggressiveness of the algorithm. | |
| 1387 In conservative mode, we ignore control dependence and simply declare | |
| 1388 all but the most trivially dead branches necessary. This mode is fast. | |
| 1389 In aggressive mode, control dependences are taken into account, which | |
| 1390 results in more dead code elimination, but at the cost of some time. | |
| 1391 | |
| 1392 FIXME: Aggressive mode before PRE doesn't work currently because | |
| 1393 the dominance info is not invalidated after DCE1. This is | |
| 1394 not an issue right now because we only run aggressive DCE | |
| 1395 as the last tree SSA pass, but keep this in mind when you | |
| 1396 start experimenting with pass ordering. */ | |
| 1397 | |
| 1398 static unsigned int | |
| 1399 perform_tree_ssa_dce (bool aggressive) | |
| 1400 { | |
| 1401 struct edge_list *el = NULL; | |
| 1402 bool something_changed = 0; | |
| 1403 | |
|
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1404 /* Preheaders are needed for SCEV to work. |
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1405 Simple lateches and recorded exits improve chances that loop will |
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1406 proved to be finite in testcases such as in loop-15.c and loop-24.c */ |
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1407 if (aggressive) |
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1408 loop_optimizer_init (LOOPS_NORMAL |
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1409 | LOOPS_HAVE_RECORDED_EXITS); |
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1410 |
| 0 | 1411 tree_dce_init (aggressive); |
| 1412 | |
| 1413 if (aggressive) | |
| 1414 { | |
| 1415 /* Compute control dependence. */ | |
| 1416 timevar_push (TV_CONTROL_DEPENDENCES); | |
| 1417 calculate_dominance_info (CDI_POST_DOMINATORS); | |
| 1418 el = create_edge_list (); | |
| 1419 find_all_control_dependences (el); | |
| 1420 timevar_pop (TV_CONTROL_DEPENDENCES); | |
| 1421 | |
| 1422 visited_control_parents = sbitmap_alloc (last_basic_block); | |
| 1423 sbitmap_zero (visited_control_parents); | |
| 1424 | |
| 1425 mark_dfs_back_edges (); | |
| 1426 } | |
| 1427 | |
| 1428 find_obviously_necessary_stmts (el); | |
| 1429 | |
|
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1430 if (aggressive) |
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1431 loop_optimizer_finalize (); |
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1432 |
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1433 longest_chain = 0; |
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1434 total_chain = 0; |
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1435 nr_walks = 0; |
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1436 chain_ovfl = false; |
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1437 visited = BITMAP_ALLOC (NULL); |
| 0 | 1438 propagate_necessity (el); |
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1439 BITMAP_FREE (visited); |
| 0 | 1440 |
| 1441 something_changed |= eliminate_unnecessary_stmts (); | |
| 1442 something_changed |= cfg_altered; | |
| 1443 | |
| 1444 /* We do not update postdominators, so free them unconditionally. */ | |
| 1445 free_dominance_info (CDI_POST_DOMINATORS); | |
| 1446 | |
| 1447 /* If we removed paths in the CFG, then we need to update | |
| 1448 dominators as well. I haven't investigated the possibility | |
| 1449 of incrementally updating dominators. */ | |
| 1450 if (cfg_altered) | |
| 1451 free_dominance_info (CDI_DOMINATORS); | |
| 1452 | |
| 1453 statistics_counter_event (cfun, "Statements deleted", stats.removed); | |
| 1454 statistics_counter_event (cfun, "PHI nodes deleted", stats.removed_phis); | |
| 1455 | |
| 1456 /* Debugging dumps. */ | |
| 1457 if (dump_file && (dump_flags & (TDF_STATS|TDF_DETAILS))) | |
| 1458 print_stats (); | |
| 1459 | |
| 1460 tree_dce_done (aggressive); | |
| 1461 | |
| 1462 free_edge_list (el); | |
| 1463 | |
| 1464 if (something_changed) | |
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1465 return (TODO_update_ssa | TODO_cleanup_cfg | TODO_ggc_collect |
| 0 | 1466 | TODO_remove_unused_locals); |
| 1467 else | |
| 1468 return 0; | |
| 1469 } | |
| 1470 | |
| 1471 /* Pass entry points. */ | |
| 1472 static unsigned int | |
| 1473 tree_ssa_dce (void) | |
| 1474 { | |
| 1475 return perform_tree_ssa_dce (/*aggressive=*/false); | |
| 1476 } | |
| 1477 | |
| 1478 static unsigned int | |
| 1479 tree_ssa_dce_loop (void) | |
| 1480 { | |
| 1481 unsigned int todo; | |
| 1482 todo = perform_tree_ssa_dce (/*aggressive=*/false); | |
| 1483 if (todo) | |
| 1484 { | |
| 1485 free_numbers_of_iterations_estimates (); | |
| 1486 scev_reset (); | |
| 1487 } | |
| 1488 return todo; | |
| 1489 } | |
| 1490 | |
| 1491 static unsigned int | |
| 1492 tree_ssa_cd_dce (void) | |
| 1493 { | |
| 1494 return perform_tree_ssa_dce (/*aggressive=*/optimize >= 2); | |
| 1495 } | |
| 1496 | |
| 1497 static bool | |
| 1498 gate_dce (void) | |
| 1499 { | |
| 1500 return flag_tree_dce != 0; | |
| 1501 } | |
| 1502 | |
| 1503 struct gimple_opt_pass pass_dce = | |
| 1504 { | |
| 1505 { | |
| 1506 GIMPLE_PASS, | |
| 1507 "dce", /* name */ | |
| 1508 gate_dce, /* gate */ | |
| 1509 tree_ssa_dce, /* execute */ | |
| 1510 NULL, /* sub */ | |
| 1511 NULL, /* next */ | |
| 1512 0, /* static_pass_number */ | |
| 1513 TV_TREE_DCE, /* tv_id */ | |
| 1514 PROP_cfg | PROP_ssa, /* properties_required */ | |
| 1515 0, /* properties_provided */ | |
| 1516 0, /* properties_destroyed */ | |
| 1517 0, /* todo_flags_start */ | |
| 1518 TODO_dump_func | TODO_verify_ssa /* todo_flags_finish */ | |
| 1519 } | |
| 1520 }; | |
| 1521 | |
| 1522 struct gimple_opt_pass pass_dce_loop = | |
| 1523 { | |
| 1524 { | |
| 1525 GIMPLE_PASS, | |
| 1526 "dceloop", /* name */ | |
| 1527 gate_dce, /* gate */ | |
| 1528 tree_ssa_dce_loop, /* execute */ | |
| 1529 NULL, /* sub */ | |
| 1530 NULL, /* next */ | |
| 1531 0, /* static_pass_number */ | |
| 1532 TV_TREE_DCE, /* tv_id */ | |
| 1533 PROP_cfg | PROP_ssa, /* properties_required */ | |
| 1534 0, /* properties_provided */ | |
| 1535 0, /* properties_destroyed */ | |
| 1536 0, /* todo_flags_start */ | |
| 1537 TODO_dump_func | TODO_verify_ssa /* todo_flags_finish */ | |
| 1538 } | |
| 1539 }; | |
| 1540 | |
| 1541 struct gimple_opt_pass pass_cd_dce = | |
| 1542 { | |
| 1543 { | |
| 1544 GIMPLE_PASS, | |
| 1545 "cddce", /* name */ | |
| 1546 gate_dce, /* gate */ | |
| 1547 tree_ssa_cd_dce, /* execute */ | |
| 1548 NULL, /* sub */ | |
| 1549 NULL, /* next */ | |
| 1550 0, /* static_pass_number */ | |
| 1551 TV_TREE_CD_DCE, /* tv_id */ | |
| 1552 PROP_cfg | PROP_ssa, /* properties_required */ | |
| 1553 0, /* properties_provided */ | |
| 1554 0, /* properties_destroyed */ | |
| 1555 0, /* todo_flags_start */ | |
| 1556 TODO_dump_func | TODO_verify_ssa | |
| 1557 | TODO_verify_flow /* todo_flags_finish */ | |
| 1558 } | |
| 1559 }; |