Mercurial > hg > CbC > CbC_gcc
annotate gcc/cfgbuild.c @ 55:77e2b8dfacca gcc-4.4.5
update it from 4.4.3 to 4.5.0
| author | ryoma <e075725@ie.u-ryukyu.ac.jp> |
|---|---|
| date | Fri, 12 Feb 2010 23:39:51 +0900 |
| parents | a06113de4d67 |
| children | b7f97abdc517 |
| rev | line source |
|---|---|
| 0 | 1 /* Control flow graph building code for GNU compiler. |
| 2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, | |
| 3 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008 | |
| 4 Free Software Foundation, Inc. | |
| 5 | |
| 6 This file is part of GCC. | |
| 7 | |
| 8 GCC is free software; you can redistribute it and/or modify it under | |
| 9 the terms of the GNU General Public License as published by the Free | |
| 10 Software Foundation; either version 3, or (at your option) any later | |
| 11 version. | |
| 12 | |
| 13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
| 14 WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 16 for more details. | |
| 17 | |
| 18 You should have received a copy of the GNU General Public License | |
| 19 along with GCC; see the file COPYING3. If not see | |
| 20 <http://www.gnu.org/licenses/>. */ | |
| 21 | |
| 22 | |
| 23 #include "config.h" | |
| 24 #include "system.h" | |
| 25 #include "coretypes.h" | |
| 26 #include "tm.h" | |
| 27 #include "tree.h" | |
| 28 #include "rtl.h" | |
| 29 #include "hard-reg-set.h" | |
| 30 #include "basic-block.h" | |
| 31 #include "regs.h" | |
| 32 #include "flags.h" | |
| 33 #include "output.h" | |
| 34 #include "function.h" | |
| 35 #include "except.h" | |
|
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36 #include "expr.h" |
| 0 | 37 #include "toplev.h" |
| 38 #include "timevar.h" | |
| 39 | |
| 40 static void make_edges (basic_block, basic_block, int); | |
| 41 static void make_label_edge (sbitmap, basic_block, rtx, int); | |
| 42 static void find_bb_boundaries (basic_block); | |
| 43 static void compute_outgoing_frequencies (basic_block); | |
| 44 | |
| 45 /* Return true if insn is something that should be contained inside basic | |
| 46 block. */ | |
| 47 | |
| 48 bool | |
| 49 inside_basic_block_p (const_rtx insn) | |
| 50 { | |
| 51 switch (GET_CODE (insn)) | |
| 52 { | |
| 53 case CODE_LABEL: | |
| 54 /* Avoid creating of basic block for jumptables. */ | |
| 55 return (NEXT_INSN (insn) == 0 | |
| 56 || !JUMP_P (NEXT_INSN (insn)) | |
| 57 || (GET_CODE (PATTERN (NEXT_INSN (insn))) != ADDR_VEC | |
| 58 && GET_CODE (PATTERN (NEXT_INSN (insn))) != ADDR_DIFF_VEC)); | |
| 59 | |
| 60 case JUMP_INSN: | |
| 61 return (GET_CODE (PATTERN (insn)) != ADDR_VEC | |
| 62 && GET_CODE (PATTERN (insn)) != ADDR_DIFF_VEC); | |
| 63 | |
| 64 case CALL_INSN: | |
| 65 case INSN: | |
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66 case DEBUG_INSN: |
| 0 | 67 return true; |
| 68 | |
| 69 case BARRIER: | |
| 70 case NOTE: | |
| 71 return false; | |
| 72 | |
| 73 default: | |
| 74 gcc_unreachable (); | |
| 75 } | |
| 76 } | |
| 77 | |
| 78 /* Return true if INSN may cause control flow transfer, so it should be last in | |
| 79 the basic block. */ | |
| 80 | |
| 81 bool | |
| 82 control_flow_insn_p (const_rtx insn) | |
| 83 { | |
| 84 switch (GET_CODE (insn)) | |
| 85 { | |
| 86 case NOTE: | |
| 87 case CODE_LABEL: | |
|
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88 case DEBUG_INSN: |
| 0 | 89 return false; |
| 90 | |
| 91 case JUMP_INSN: | |
| 92 /* Jump insn always causes control transfer except for tablejumps. */ | |
| 93 return (GET_CODE (PATTERN (insn)) != ADDR_VEC | |
| 94 && GET_CODE (PATTERN (insn)) != ADDR_DIFF_VEC); | |
| 95 | |
| 96 case CALL_INSN: | |
| 97 /* Noreturn and sibling call instructions terminate the basic blocks | |
| 98 (but only if they happen unconditionally). */ | |
| 99 if ((SIBLING_CALL_P (insn) | |
| 100 || find_reg_note (insn, REG_NORETURN, 0)) | |
| 101 && GET_CODE (PATTERN (insn)) != COND_EXEC) | |
| 102 return true; | |
|
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103 |
| 0 | 104 /* Call insn may return to the nonlocal goto handler. */ |
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105 if (can_nonlocal_goto (insn)) |
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106 return true; |
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107 break; |
| 0 | 108 |
| 109 case INSN: | |
| 110 /* Treat trap instructions like noreturn calls (same provision). */ | |
| 111 if (GET_CODE (PATTERN (insn)) == TRAP_IF | |
| 112 && XEXP (PATTERN (insn), 0) == const1_rtx) | |
| 113 return true; | |
|
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114 if (!flag_non_call_exceptions) |
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115 return false; |
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116 break; |
| 0 | 117 |
| 118 case BARRIER: | |
| 119 /* It is nonsense to reach barrier when looking for the | |
| 120 end of basic block, but before dead code is eliminated | |
| 121 this may happen. */ | |
| 122 return false; | |
| 123 | |
| 124 default: | |
| 125 gcc_unreachable (); | |
| 126 } | |
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127 |
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128 return can_throw_internal (insn); |
| 0 | 129 } |
| 130 | |
| 131 | |
| 132 /* Create an edge between two basic blocks. FLAGS are auxiliary information | |
| 133 about the edge that is accumulated between calls. */ | |
| 134 | |
| 135 /* Create an edge from a basic block to a label. */ | |
| 136 | |
| 137 static void | |
| 138 make_label_edge (sbitmap edge_cache, basic_block src, rtx label, int flags) | |
| 139 { | |
| 140 gcc_assert (LABEL_P (label)); | |
| 141 | |
| 142 /* If the label was never emitted, this insn is junk, but avoid a | |
| 143 crash trying to refer to BLOCK_FOR_INSN (label). This can happen | |
| 144 as a result of a syntax error and a diagnostic has already been | |
| 145 printed. */ | |
| 146 | |
| 147 if (INSN_UID (label) == 0) | |
| 148 return; | |
| 149 | |
| 150 cached_make_edge (edge_cache, src, BLOCK_FOR_INSN (label), flags); | |
| 151 } | |
| 152 | |
| 153 /* Create the edges generated by INSN in REGION. */ | |
| 154 | |
| 155 void | |
| 156 rtl_make_eh_edge (sbitmap edge_cache, basic_block src, rtx insn) | |
| 157 { | |
|
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158 eh_landing_pad lp = get_eh_landing_pad_from_rtx (insn); |
| 0 | 159 |
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160 if (lp) |
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161 { |
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162 rtx label = lp->landing_pad; |
| 0 | 163 |
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164 /* During initial rtl generation, use the post_landing_pad. */ |
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165 if (label == NULL) |
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166 { |
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167 gcc_assert (lp->post_landing_pad); |
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168 label = label_rtx (lp->post_landing_pad); |
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169 } |
| 0 | 170 |
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171 make_label_edge (edge_cache, src, label, |
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172 EDGE_ABNORMAL | EDGE_EH |
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173 | (CALL_P (insn) ? EDGE_ABNORMAL_CALL : 0)); |
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174 } |
| 0 | 175 } |
| 176 | |
| 177 /* States of basic block as seen by find_many_sub_basic_blocks. */ | |
| 178 enum state { | |
| 179 /* Basic blocks created via split_block belong to this state. | |
| 180 make_edges will examine these basic blocks to see if we need to | |
| 181 create edges going out of them. */ | |
| 182 BLOCK_NEW = 0, | |
| 183 | |
| 184 /* Basic blocks that do not need examining belong to this state. | |
| 185 These blocks will be left intact. In particular, make_edges will | |
| 186 not create edges going out of these basic blocks. */ | |
| 187 BLOCK_ORIGINAL, | |
| 188 | |
| 189 /* Basic blocks that may need splitting (due to a label appearing in | |
| 190 the middle, etc) belong to this state. After splitting them, | |
| 191 make_edges will create edges going out of them as needed. */ | |
| 192 BLOCK_TO_SPLIT | |
| 193 }; | |
| 194 | |
| 195 #define STATE(BB) (enum state) ((size_t) (BB)->aux) | |
| 196 #define SET_STATE(BB, STATE) ((BB)->aux = (void *) (size_t) (STATE)) | |
| 197 | |
| 198 /* Used internally by purge_dead_tablejump_edges, ORed into state. */ | |
| 199 #define BLOCK_USED_BY_TABLEJUMP 32 | |
| 200 #define FULL_STATE(BB) ((size_t) (BB)->aux) | |
| 201 | |
| 202 /* Identify the edges going out of basic blocks between MIN and MAX, | |
| 203 inclusive, that have their states set to BLOCK_NEW or | |
| 204 BLOCK_TO_SPLIT. | |
| 205 | |
| 206 UPDATE_P should be nonzero if we are updating CFG and zero if we | |
| 207 are building CFG from scratch. */ | |
| 208 | |
| 209 static void | |
| 210 make_edges (basic_block min, basic_block max, int update_p) | |
| 211 { | |
| 212 basic_block bb; | |
| 213 sbitmap edge_cache = NULL; | |
| 214 | |
| 215 /* Heavy use of computed goto in machine-generated code can lead to | |
| 216 nearly fully-connected CFGs. In that case we spend a significant | |
| 217 amount of time searching the edge lists for duplicates. */ | |
| 218 if (forced_labels || cfun->cfg->max_jumptable_ents > 100) | |
| 219 edge_cache = sbitmap_alloc (last_basic_block); | |
| 220 | |
| 221 /* By nature of the way these get numbered, ENTRY_BLOCK_PTR->next_bb block | |
| 222 is always the entry. */ | |
| 223 if (min == ENTRY_BLOCK_PTR->next_bb) | |
| 224 make_edge (ENTRY_BLOCK_PTR, min, EDGE_FALLTHRU); | |
| 225 | |
| 226 FOR_BB_BETWEEN (bb, min, max->next_bb, next_bb) | |
| 227 { | |
| 228 rtx insn, x; | |
| 229 enum rtx_code code; | |
| 230 edge e; | |
| 231 edge_iterator ei; | |
| 232 | |
| 233 if (STATE (bb) == BLOCK_ORIGINAL) | |
| 234 continue; | |
| 235 | |
| 236 /* If we have an edge cache, cache edges going out of BB. */ | |
| 237 if (edge_cache) | |
| 238 { | |
| 239 sbitmap_zero (edge_cache); | |
| 240 if (update_p) | |
| 241 { | |
| 242 FOR_EACH_EDGE (e, ei, bb->succs) | |
| 243 if (e->dest != EXIT_BLOCK_PTR) | |
| 244 SET_BIT (edge_cache, e->dest->index); | |
| 245 } | |
| 246 } | |
| 247 | |
| 248 if (LABEL_P (BB_HEAD (bb)) | |
| 249 && LABEL_ALT_ENTRY_P (BB_HEAD (bb))) | |
| 250 cached_make_edge (NULL, ENTRY_BLOCK_PTR, bb, 0); | |
| 251 | |
| 252 /* Examine the last instruction of the block, and discover the | |
| 253 ways we can leave the block. */ | |
| 254 | |
| 255 insn = BB_END (bb); | |
| 256 code = GET_CODE (insn); | |
| 257 | |
| 258 /* A branch. */ | |
| 259 if (code == JUMP_INSN) | |
| 260 { | |
| 261 rtx tmp; | |
| 262 | |
| 263 /* Recognize a non-local goto as a branch outside the | |
| 264 current function. */ | |
|
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265 if (find_reg_note (insn, REG_NON_LOCAL_GOTO, NULL_RTX)) |
| 0 | 266 ; |
| 267 | |
| 268 /* Recognize a tablejump and do the right thing. */ | |
| 269 else if (tablejump_p (insn, NULL, &tmp)) | |
| 270 { | |
| 271 rtvec vec; | |
| 272 int j; | |
| 273 | |
| 274 if (GET_CODE (PATTERN (tmp)) == ADDR_VEC) | |
| 275 vec = XVEC (PATTERN (tmp), 0); | |
| 276 else | |
| 277 vec = XVEC (PATTERN (tmp), 1); | |
| 278 | |
| 279 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j) | |
| 280 make_label_edge (edge_cache, bb, | |
| 281 XEXP (RTVEC_ELT (vec, j), 0), 0); | |
| 282 | |
| 283 /* Some targets (eg, ARM) emit a conditional jump that also | |
| 284 contains the out-of-range target. Scan for these and | |
| 285 add an edge if necessary. */ | |
| 286 if ((tmp = single_set (insn)) != NULL | |
| 287 && SET_DEST (tmp) == pc_rtx | |
| 288 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE | |
| 289 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF) | |
| 290 make_label_edge (edge_cache, bb, | |
| 291 XEXP (XEXP (SET_SRC (tmp), 2), 0), 0); | |
| 292 } | |
| 293 | |
| 294 /* If this is a computed jump, then mark it as reaching | |
| 295 everything on the forced_labels list. */ | |
| 296 else if (computed_jump_p (insn)) | |
| 297 { | |
| 298 for (x = forced_labels; x; x = XEXP (x, 1)) | |
| 299 make_label_edge (edge_cache, bb, XEXP (x, 0), EDGE_ABNORMAL); | |
| 300 } | |
| 301 | |
| 302 /* Returns create an exit out. */ | |
| 303 else if (returnjump_p (insn)) | |
| 304 cached_make_edge (edge_cache, bb, EXIT_BLOCK_PTR, 0); | |
| 305 | |
|
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306 /* Recognize asm goto and do the right thing. */ |
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307 else if ((tmp = extract_asm_operands (PATTERN (insn))) != NULL) |
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308 { |
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309 int i, n = ASM_OPERANDS_LABEL_LENGTH (tmp); |
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310 for (i = 0; i < n; ++i) |
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311 make_label_edge (edge_cache, bb, |
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312 XEXP (ASM_OPERANDS_LABEL (tmp, i), 0), 0); |
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313 } |
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314 |
| 0 | 315 /* Otherwise, we have a plain conditional or unconditional jump. */ |
| 316 else | |
| 317 { | |
| 318 gcc_assert (JUMP_LABEL (insn)); | |
| 319 make_label_edge (edge_cache, bb, JUMP_LABEL (insn), 0); | |
| 320 } | |
| 321 } | |
| 322 | |
| 323 /* If this is a sibling call insn, then this is in effect a combined call | |
| 324 and return, and so we need an edge to the exit block. No need to | |
| 325 worry about EH edges, since we wouldn't have created the sibling call | |
| 326 in the first place. */ | |
| 327 if (code == CALL_INSN && SIBLING_CALL_P (insn)) | |
| 328 cached_make_edge (edge_cache, bb, EXIT_BLOCK_PTR, | |
| 329 EDGE_SIBCALL | EDGE_ABNORMAL); | |
| 330 | |
| 331 /* If this is a CALL_INSN, then mark it as reaching the active EH | |
| 332 handler for this CALL_INSN. If we're handling non-call | |
| 333 exceptions then any insn can reach any of the active handlers. | |
| 334 Also mark the CALL_INSN as reaching any nonlocal goto handler. */ | |
| 335 else if (code == CALL_INSN || flag_non_call_exceptions) | |
| 336 { | |
| 337 /* Add any appropriate EH edges. */ | |
| 338 rtl_make_eh_edge (edge_cache, bb, insn); | |
| 339 | |
| 340 if (code == CALL_INSN && nonlocal_goto_handler_labels) | |
| 341 { | |
| 342 /* ??? This could be made smarter: in some cases it's possible | |
| 343 to tell that certain calls will not do a nonlocal goto. | |
| 344 For example, if the nested functions that do the nonlocal | |
| 345 gotos do not have their addresses taken, then only calls to | |
| 346 those functions or to other nested functions that use them | |
| 347 could possibly do nonlocal gotos. */ | |
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348 if (can_nonlocal_goto (insn)) |
| 0 | 349 for (x = nonlocal_goto_handler_labels; x; x = XEXP (x, 1)) |
| 350 make_label_edge (edge_cache, bb, XEXP (x, 0), | |
| 351 EDGE_ABNORMAL | EDGE_ABNORMAL_CALL); | |
| 352 } | |
| 353 } | |
| 354 | |
| 355 /* Find out if we can drop through to the next block. */ | |
| 356 insn = NEXT_INSN (insn); | |
| 357 e = find_edge (bb, EXIT_BLOCK_PTR); | |
| 358 if (e && e->flags & EDGE_FALLTHRU) | |
| 359 insn = NULL; | |
| 360 | |
| 361 while (insn | |
| 362 && NOTE_P (insn) | |
| 363 && NOTE_KIND (insn) != NOTE_INSN_BASIC_BLOCK) | |
| 364 insn = NEXT_INSN (insn); | |
| 365 | |
| 366 if (!insn) | |
| 367 cached_make_edge (edge_cache, bb, EXIT_BLOCK_PTR, EDGE_FALLTHRU); | |
| 368 else if (bb->next_bb != EXIT_BLOCK_PTR) | |
| 369 { | |
| 370 if (insn == BB_HEAD (bb->next_bb)) | |
| 371 cached_make_edge (edge_cache, bb, bb->next_bb, EDGE_FALLTHRU); | |
| 372 } | |
| 373 } | |
| 374 | |
| 375 if (edge_cache) | |
| 376 sbitmap_vector_free (edge_cache); | |
| 377 } | |
| 378 | |
| 379 static void | |
| 380 mark_tablejump_edge (rtx label) | |
| 381 { | |
| 382 basic_block bb; | |
| 383 | |
| 384 gcc_assert (LABEL_P (label)); | |
| 385 /* See comment in make_label_edge. */ | |
| 386 if (INSN_UID (label) == 0) | |
| 387 return; | |
| 388 bb = BLOCK_FOR_INSN (label); | |
| 389 SET_STATE (bb, FULL_STATE (bb) | BLOCK_USED_BY_TABLEJUMP); | |
| 390 } | |
| 391 | |
| 392 static void | |
| 393 purge_dead_tablejump_edges (basic_block bb, rtx table) | |
| 394 { | |
| 395 rtx insn = BB_END (bb), tmp; | |
| 396 rtvec vec; | |
| 397 int j; | |
| 398 edge_iterator ei; | |
| 399 edge e; | |
| 400 | |
| 401 if (GET_CODE (PATTERN (table)) == ADDR_VEC) | |
| 402 vec = XVEC (PATTERN (table), 0); | |
| 403 else | |
| 404 vec = XVEC (PATTERN (table), 1); | |
| 405 | |
| 406 for (j = GET_NUM_ELEM (vec) - 1; j >= 0; --j) | |
| 407 mark_tablejump_edge (XEXP (RTVEC_ELT (vec, j), 0)); | |
| 408 | |
| 409 /* Some targets (eg, ARM) emit a conditional jump that also | |
| 410 contains the out-of-range target. Scan for these and | |
| 411 add an edge if necessary. */ | |
| 412 if ((tmp = single_set (insn)) != NULL | |
| 413 && SET_DEST (tmp) == pc_rtx | |
| 414 && GET_CODE (SET_SRC (tmp)) == IF_THEN_ELSE | |
| 415 && GET_CODE (XEXP (SET_SRC (tmp), 2)) == LABEL_REF) | |
| 416 mark_tablejump_edge (XEXP (XEXP (SET_SRC (tmp), 2), 0)); | |
| 417 | |
| 418 for (ei = ei_start (bb->succs); (e = ei_safe_edge (ei)); ) | |
| 419 { | |
| 420 if (FULL_STATE (e->dest) & BLOCK_USED_BY_TABLEJUMP) | |
| 421 SET_STATE (e->dest, FULL_STATE (e->dest) | |
| 422 & ~(size_t) BLOCK_USED_BY_TABLEJUMP); | |
| 423 else if (!(e->flags & (EDGE_ABNORMAL | EDGE_EH))) | |
| 424 { | |
| 425 remove_edge (e); | |
| 426 continue; | |
| 427 } | |
| 428 ei_next (&ei); | |
| 429 } | |
| 430 } | |
| 431 | |
| 432 /* Scan basic block BB for possible BB boundaries inside the block | |
| 433 and create new basic blocks in the progress. */ | |
| 434 | |
| 435 static void | |
| 436 find_bb_boundaries (basic_block bb) | |
| 437 { | |
| 438 basic_block orig_bb = bb; | |
| 439 rtx insn = BB_HEAD (bb); | |
| 440 rtx end = BB_END (bb), x; | |
| 441 rtx table; | |
| 442 rtx flow_transfer_insn = NULL_RTX; | |
| 443 edge fallthru = NULL; | |
| 444 | |
| 445 if (insn == BB_END (bb)) | |
| 446 return; | |
| 447 | |
| 448 if (LABEL_P (insn)) | |
| 449 insn = NEXT_INSN (insn); | |
| 450 | |
| 451 /* Scan insn chain and try to find new basic block boundaries. */ | |
| 452 while (1) | |
| 453 { | |
| 454 enum rtx_code code = GET_CODE (insn); | |
| 455 | |
|
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456 /* In case we've previously seen an insn that effects a control |
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457 flow transfer, split the block. */ |
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458 if ((flow_transfer_insn || code == CODE_LABEL) |
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459 && inside_basic_block_p (insn)) |
| 0 | 460 { |
| 461 fallthru = split_block (bb, PREV_INSN (insn)); | |
| 462 if (flow_transfer_insn) | |
| 463 { | |
| 464 BB_END (bb) = flow_transfer_insn; | |
| 465 | |
| 466 /* Clean up the bb field for the insns between the blocks. */ | |
| 467 for (x = NEXT_INSN (flow_transfer_insn); | |
| 468 x != BB_HEAD (fallthru->dest); | |
| 469 x = NEXT_INSN (x)) | |
| 470 if (!BARRIER_P (x)) | |
| 471 set_block_for_insn (x, NULL); | |
| 472 } | |
| 473 | |
| 474 bb = fallthru->dest; | |
| 475 remove_edge (fallthru); | |
| 476 flow_transfer_insn = NULL_RTX; | |
|
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477 if (code == CODE_LABEL && LABEL_ALT_ENTRY_P (insn)) |
| 0 | 478 make_edge (ENTRY_BLOCK_PTR, bb, 0); |
| 479 } | |
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480 else if (code == BARRIER) |
| 0 | 481 { |
|
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482 /* __builtin_unreachable () may cause a barrier to be emitted in |
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483 the middle of a BB. We need to split it in the same manner as |
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484 if the barrier were preceded by a control_flow_insn_p insn. */ |
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485 if (!flow_transfer_insn) |
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486 flow_transfer_insn = prev_nonnote_insn_bb (insn); |
| 0 | 487 } |
| 488 | |
| 489 if (control_flow_insn_p (insn)) | |
| 490 flow_transfer_insn = insn; | |
| 491 if (insn == end) | |
| 492 break; | |
| 493 insn = NEXT_INSN (insn); | |
| 494 } | |
| 495 | |
| 496 /* In case expander replaced normal insn by sequence terminating by | |
| 497 return and barrier, or possibly other sequence not behaving like | |
| 498 ordinary jump, we need to take care and move basic block boundary. */ | |
| 499 if (flow_transfer_insn) | |
| 500 { | |
| 501 BB_END (bb) = flow_transfer_insn; | |
| 502 | |
| 503 /* Clean up the bb field for the insns that do not belong to BB. */ | |
| 504 x = flow_transfer_insn; | |
| 505 while (x != end) | |
| 506 { | |
| 507 x = NEXT_INSN (x); | |
| 508 if (!BARRIER_P (x)) | |
| 509 set_block_for_insn (x, NULL); | |
| 510 } | |
| 511 } | |
| 512 | |
| 513 /* We've possibly replaced the conditional jump by conditional jump | |
| 514 followed by cleanup at fallthru edge, so the outgoing edges may | |
| 515 be dead. */ | |
| 516 purge_dead_edges (bb); | |
| 517 | |
| 518 /* purge_dead_edges doesn't handle tablejump's, but if we have split the | |
| 519 basic block, we might need to kill some edges. */ | |
| 520 if (bb != orig_bb && tablejump_p (BB_END (bb), NULL, &table)) | |
| 521 purge_dead_tablejump_edges (bb, table); | |
| 522 } | |
| 523 | |
| 524 /* Assume that frequency of basic block B is known. Compute frequencies | |
| 525 and probabilities of outgoing edges. */ | |
| 526 | |
| 527 static void | |
| 528 compute_outgoing_frequencies (basic_block b) | |
| 529 { | |
| 530 edge e, f; | |
| 531 edge_iterator ei; | |
| 532 | |
| 533 if (EDGE_COUNT (b->succs) == 2) | |
| 534 { | |
| 535 rtx note = find_reg_note (BB_END (b), REG_BR_PROB, NULL); | |
| 536 int probability; | |
| 537 | |
| 538 if (note) | |
| 539 { | |
| 540 probability = INTVAL (XEXP (note, 0)); | |
| 541 e = BRANCH_EDGE (b); | |
| 542 e->probability = probability; | |
| 543 e->count = ((b->count * probability + REG_BR_PROB_BASE / 2) | |
| 544 / REG_BR_PROB_BASE); | |
| 545 f = FALLTHRU_EDGE (b); | |
| 546 f->probability = REG_BR_PROB_BASE - probability; | |
| 547 f->count = b->count - e->count; | |
| 548 return; | |
| 549 } | |
| 550 } | |
| 551 | |
| 552 if (single_succ_p (b)) | |
| 553 { | |
| 554 e = single_succ_edge (b); | |
| 555 e->probability = REG_BR_PROB_BASE; | |
| 556 e->count = b->count; | |
| 557 return; | |
| 558 } | |
| 559 guess_outgoing_edge_probabilities (b); | |
| 560 if (b->count) | |
| 561 FOR_EACH_EDGE (e, ei, b->succs) | |
| 562 e->count = ((b->count * e->probability + REG_BR_PROB_BASE / 2) | |
| 563 / REG_BR_PROB_BASE); | |
| 564 } | |
| 565 | |
| 566 /* Assume that some pass has inserted labels or control flow | |
| 567 instructions within a basic block. Split basic blocks as needed | |
| 568 and create edges. */ | |
| 569 | |
| 570 void | |
| 571 find_many_sub_basic_blocks (sbitmap blocks) | |
| 572 { | |
| 573 basic_block bb, min, max; | |
| 574 | |
| 575 FOR_EACH_BB (bb) | |
| 576 SET_STATE (bb, | |
| 577 TEST_BIT (blocks, bb->index) ? BLOCK_TO_SPLIT : BLOCK_ORIGINAL); | |
| 578 | |
| 579 FOR_EACH_BB (bb) | |
| 580 if (STATE (bb) == BLOCK_TO_SPLIT) | |
| 581 find_bb_boundaries (bb); | |
| 582 | |
| 583 FOR_EACH_BB (bb) | |
| 584 if (STATE (bb) != BLOCK_ORIGINAL) | |
| 585 break; | |
| 586 | |
| 587 min = max = bb; | |
| 588 for (; bb != EXIT_BLOCK_PTR; bb = bb->next_bb) | |
| 589 if (STATE (bb) != BLOCK_ORIGINAL) | |
| 590 max = bb; | |
| 591 | |
| 592 /* Now re-scan and wire in all edges. This expect simple (conditional) | |
| 593 jumps at the end of each new basic blocks. */ | |
| 594 make_edges (min, max, 1); | |
| 595 | |
| 596 /* Update branch probabilities. Expect only (un)conditional jumps | |
| 597 to be created with only the forward edges. */ | |
| 598 if (profile_status != PROFILE_ABSENT) | |
| 599 FOR_BB_BETWEEN (bb, min, max->next_bb, next_bb) | |
| 600 { | |
| 601 edge e; | |
| 602 edge_iterator ei; | |
| 603 | |
| 604 if (STATE (bb) == BLOCK_ORIGINAL) | |
| 605 continue; | |
| 606 if (STATE (bb) == BLOCK_NEW) | |
| 607 { | |
| 608 bb->count = 0; | |
| 609 bb->frequency = 0; | |
| 610 FOR_EACH_EDGE (e, ei, bb->preds) | |
| 611 { | |
| 612 bb->count += e->count; | |
| 613 bb->frequency += EDGE_FREQUENCY (e); | |
| 614 } | |
| 615 } | |
| 616 | |
| 617 compute_outgoing_frequencies (bb); | |
| 618 } | |
| 619 | |
| 620 FOR_EACH_BB (bb) | |
| 621 SET_STATE (bb, 0); | |
| 622 } |