1/* params.def - Run-time parameters. 2 Copyright (C) 2001, 2002, 2004, 2005 Free Software Foundation, Inc. 3 Written by Mark Mitchell <mark@codesourcery.com>. 4 5This file is part of GCC. 6 7GCC is free software; you can redistribute it and/or modify it under 8the terms of the GNU General Public License as published by the Free 9Software Foundation; either version 2, or (at your option) any later 10version. 11 12GCC is distributed in the hope that it will be useful, but WITHOUT ANY 13WARRANTY; without even the implied warranty of MERCHANTABILITY or 14FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 15for more details. 16 17You should have received a copy of the GNU General Public License 18along with GCC; see the file COPYING. If not, write to the Free 19Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 2002110-1301, USA. 21 22*/ 23 24/* This file contains definitions for language-independent 25 parameters. The DEFPARAM macro takes 6 arguments: 26 27 - The enumeral corresponding to this parameter. 28 29 - The name that can be used to set this parameter using the 30 command-line option `--param <name>=<value>'. 31 32 - A help string explaining how the parameter is used. 33 34 - A default value for the parameter. 35 36 - The minimum acceptable value for the parameter. 37 38 - The maximum acceptable value for the parameter (if greater than 39 the minimum). 40 41 Be sure to add an entry to invoke.texi summarizing the parameter. */ 42 43/* The maximum number of fields in a variable with only implicit uses 44 for which structure aliasing will consider trying to track each 45 field. The default is 5. */ 46DEFPARAM (PARAM_SALIAS_MAX_IMPLICIT_FIELDS, 47 "salias-max-implicit-fields", 48 "The maximum number of fields in a structure variable without direct structure accesses that GCC will attempt to track separately", 49 5, 0, 0) 50 51/* The maximum structure size at which the scalar replacement of 52 aggregates (SRA) pass will perform block copies. The default 53 value, 0, implies that GCC will select the most appropriate size 54 itself. */ 55DEFPARAM (PARAM_SRA_MAX_STRUCTURE_SIZE, 56 "sra-max-structure-size", 57 "The maximum structure size (in bytes) for which GCC will " 58 "use by-element copies", 59 0, 0, 0) 60 61/* The maximum number of structure fields which the SRA pass will 62 instantiate to avoid block copies. The default value, 0, implies 63 that GCC will select the appropriate value itself. */ 64DEFPARAM (PARAM_SRA_MAX_STRUCTURE_COUNT, 65 "sra-max-structure-count", 66 "The maximum number of structure fields for which GCC will " 67 "use by-element copies", 68 0, 0, 0) 69 70/* The ratio between instantiated fields and the complete structure 71 size. We say that if the ratio of the number of bytes in 72 instantiated fields to the number of bytes in the complete 73 structure exceeds this parameter, or if the number of instantiated 74 fields to the total number of fields exceeds this parameter, then 75 block copies are not used. The default is 75%. */ 76DEFPARAM (PARAM_SRA_FIELD_STRUCTURE_RATIO, 77 "sra-field-structure-ratio", 78 "The threshold ratio between instantiated fields and the total structure size", 79 75, 0, 100) 80 81/* The single function inlining limit. This is the maximum size 82 of a function counted in internal gcc instructions (not in 83 real machine instructions) that is eligible for inlining 84 by the tree inliner. 85 The default value is 450. 86 Only functions marked inline (or methods defined in the class 87 definition for C++) are affected by this. 88 There are more restrictions to inlining: If inlined functions 89 call other functions, the already inlined instructions are 90 counted and once the recursive inline limit (see 91 "max-inline-insns" parameter) is exceeded, the acceptable size 92 gets decreased. */ 93DEFPARAM (PARAM_MAX_INLINE_INSNS_SINGLE, 94 "max-inline-insns-single", 95 "The maximum number of instructions in a single function eligible for inlining", 96 450, 0, 0) 97 98/* The single function inlining limit for functions that are 99 inlined by virtue of -finline-functions (-O3). 100 This limit should be chosen to be below or equal to the limit 101 that is applied to functions marked inlined (or defined in the 102 class declaration in C++) given by the "max-inline-insns-single" 103 parameter. 104 The default value is 90. */ 105DEFPARAM (PARAM_MAX_INLINE_INSNS_AUTO, 106 "max-inline-insns-auto", 107 "The maximum number of instructions when automatically inlining", 108 90, 0, 0) 109 110DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE, 111 "max-inline-insns-recursive", 112 "The maximum number of instructions inline function can grow to via recursive inlining", 113 450, 0, 0) 114 115DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO, 116 "max-inline-insns-recursive-auto", 117 "The maximum number of instructions non-inline function can grow to via recursive inlining", 118 450, 0, 0) 119 120DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH, 121 "max-inline-recursive-depth", 122 "The maximum depth of recursive inlining for inline functions", 123 8, 0, 0) 124 125DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO, 126 "max-inline-recursive-depth-auto", 127 "The maximum depth of recursive inlining for non-inline functions", 128 8, 0, 0) 129 130DEFPARAM (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY, 131 "min-inline-recursive-probability", 132 "Inline recursively only when the probability of call being executed exceeds the parameter", 133 10, 0, 0) 134 135/* Limit the number of expansions created by the variable expansion 136 optimization to avoid register pressure. */ 137DEFPARAM (PARAM_MAX_VARIABLE_EXPANSIONS, 138 "max-variable-expansions-in-unroller", 139 "If -fvariable-expansion-in-unroller is used, the maximum number of times that an individual variable will be expanded during loop unrolling", 140 1, 0, 0) 141 142/* The maximum number of instructions to consider when looking for an 143 instruction to fill a delay slot. If more than this arbitrary 144 number of instructions is searched, the time savings from filling 145 the delay slot will be minimal so stop searching. Increasing 146 values mean more aggressive optimization, making the compile time 147 increase with probably small improvement in executable run time. */ 148DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH, 149 "max-delay-slot-insn-search", 150 "The maximum number of instructions to consider to fill a delay slot", 151 100, 0, 0) 152 153/* When trying to fill delay slots, the maximum number of instructions 154 to consider when searching for a block with valid live register 155 information. Increasing this arbitrarily chosen value means more 156 aggressive optimization, increasing the compile time. This 157 parameter should be removed when the delay slot code is rewritten 158 to maintain the control-flow graph. */ 159DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH, 160 "max-delay-slot-live-search", 161 "The maximum number of instructions to consider to find accurate live register information", 162 333, 0, 0) 163 164/* This parameter limits the number of branch elements that the 165 scheduler will track anti-dependencies through without resetting 166 the tracking mechanism. Large functions with few calls or barriers 167 can generate lists containing many 1000's of dependencies. Generally 168 the compiler either uses all available memory, or runs for far too long. */ 169DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH, 170 "max-pending-list-length", 171 "The maximum length of scheduling's pending operations list", 172 32, 0, 0) 173 174DEFPARAM(PARAM_LARGE_FUNCTION_INSNS, 175 "large-function-insns", 176 "The size of function body to be considered large", 177 2700, 0, 0) 178DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH, 179 "large-function-growth", 180 "Maximal growth due to inlining of large function (in percent)", 181 100, 0, 0) 182DEFPARAM(PARAM_LARGE_UNIT_INSNS, 183 "large-unit-insns", 184 "The size of translation unit to be considered large", 185 10000, 0, 0) 186DEFPARAM(PARAM_INLINE_UNIT_GROWTH, 187 "inline-unit-growth", 188 "how much can given compilation unit grow because of the inlining (in percent)", 189 50, 0, 0) 190DEFPARAM(PARAM_INLINE_CALL_COST, 191 "inline-call-cost", 192 "expense of call operation relative to ordinary arithmetic operations", 193 16, 0, 0) 194 195/* The GCSE optimization will be disabled if it would require 196 significantly more memory than this value. */ 197DEFPARAM(PARAM_MAX_GCSE_MEMORY, 198 "max-gcse-memory", 199 "The maximum amount of memory to be allocated by GCSE", 200 50 * 1024 * 1024, 0, 0) 201/* The number of repetitions of copy/const prop and PRE to run. */ 202DEFPARAM(PARAM_MAX_GCSE_PASSES, 203 "max-gcse-passes", 204 "The maximum number of passes to make when doing GCSE", 205 1, 1, 0) 206/* This is the threshold ratio when to perform partial redundancy 207 elimination after reload. We perform partial redundancy elimination 208 when the following holds: 209 (Redundant load execution count) 210 ------------------------------- >= GCSE_AFTER_RELOAD_PARTIAL_FRACTION 211 (Added loads execution count) */ 212DEFPARAM(PARAM_GCSE_AFTER_RELOAD_PARTIAL_FRACTION, 213 "gcse-after-reload-partial-fraction", 214 "The threshold ratio for performing partial redundancy elimination after reload", 215 3, 0, 0) 216/* This is the threshold ratio of the critical edges execution count compared to 217 the redundant loads execution count that permits performing the load 218 redundancy elimination in gcse after reload. */ 219DEFPARAM(PARAM_GCSE_AFTER_RELOAD_CRITICAL_FRACTION, 220 "gcse-after-reload-critical-fraction", 221 "The threshold ratio of critical edges execution count that permit performing redundancy elimination after reload", 222 10, 0, 0) 223/* This parameter limits the number of insns in a loop that will be unrolled, 224 and by how much the loop is unrolled. 225 226 This limit should be at most half of the peeling limits: loop unroller 227 decides to not unroll loops that iterate fewer than 2*number of allowed 228 unrollings and thus we would have loops that are neither peeled or unrolled 229 otherwise. */ 230DEFPARAM(PARAM_MAX_UNROLLED_INSNS, 231 "max-unrolled-insns", 232 "The maximum number of instructions to consider to unroll in a loop", 233 200, 0, 0) 234/* This parameter limits how many times the loop is unrolled depending 235 on number of insns really executed in each iteration. */ 236DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS, 237 "max-average-unrolled-insns", 238 "The maximum number of instructions to consider to unroll in a loop on average", 239 80, 0, 0) 240/* The maximum number of unrollings of a single loop. */ 241DEFPARAM(PARAM_MAX_UNROLL_TIMES, 242 "max-unroll-times", 243 "The maximum number of unrollings of a single loop", 244 8, 0, 0) 245/* The maximum number of insns of a peeled loop. */ 246DEFPARAM(PARAM_MAX_PEELED_INSNS, 247 "max-peeled-insns", 248 "The maximum number of insns of a peeled loop", 249 400, 0, 0) 250/* The maximum number of peelings of a single loop. */ 251DEFPARAM(PARAM_MAX_PEEL_TIMES, 252 "max-peel-times", 253 "The maximum number of peelings of a single loop", 254 16, 0, 0) 255/* The maximum number of insns of a peeled loop. */ 256DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS, 257 "max-completely-peeled-insns", 258 "The maximum number of insns of a completely peeled loop", 259 400, 0, 0) 260/* The maximum number of peelings of a single loop that is peeled completely. */ 261DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES, 262 "max-completely-peel-times", 263 "The maximum number of peelings of a single loop that is peeled completely", 264 16, 0, 0) 265/* The maximum number of insns of a peeled loop that rolls only once. */ 266DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS, 267 "max-once-peeled-insns", 268 "The maximum number of insns of a peeled loop that rolls only once", 269 400, 0, 0) 270 271/* The maximum number of insns of an unswitched loop. */ 272DEFPARAM(PARAM_MAX_UNSWITCH_INSNS, 273 "max-unswitch-insns", 274 "The maximum number of insns of an unswitched loop", 275 50, 0, 0) 276/* The maximum level of recursion in unswitch_single_loop. */ 277DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL, 278 "max-unswitch-level", 279 "The maximum number of unswitchings in a single loop", 280 3, 0, 0) 281 282/* The maximum number of iterations of a loop the brute force algorithm 283 for analysis of # of iterations of the loop tries to evaluate. */ 284DEFPARAM(PARAM_MAX_ITERATIONS_TO_TRACK, 285 "max-iterations-to-track", 286 "Bound on the number of iterations the brute force # of iterations analysis algorithm evaluates", 287 1000, 0, 0) 288 289DEFPARAM(PARAM_MAX_SMS_LOOP_NUMBER, 290 "max-sms-loop-number", 291 "Maximum number of loops to perform swing modulo scheduling on (mainly for debugging)", 292 -1, -1, -1) 293 294/* This parameter is used to tune SMS MAX II calculations. */ 295DEFPARAM(PARAM_SMS_MAX_II_FACTOR, 296 "sms-max-ii-factor", 297 "A factor for tuning the upper bound that swing modulo scheduler uses for scheduling a loop", 298 100, 0, 0) 299DEFPARAM(PARAM_SMS_DFA_HISTORY, 300 "sms-dfa-history", 301 "The number of cycles the swing modulo scheduler considers when checking conflicts using DFA", 302 0, 0, 0) 303DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD, 304 "sms-loop-average-count-threshold", 305 "A threshold on the average loop count considered by the swing modulo scheduler", 306 0, 0, 0) 307 308DEFPARAM(HOT_BB_COUNT_FRACTION, 309 "hot-bb-count-fraction", 310 "Select fraction of the maximal count of repetitions of basic block in program given basic block needs to have to be considered hot", 311 10000, 0, 0) 312DEFPARAM(HOT_BB_FREQUENCY_FRACTION, 313 "hot-bb-frequency-fraction", 314 "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot", 315 1000, 0, 0) 316 317/* For guessed profiles, the loops having unknown number of iterations 318 are predicted to iterate relatively few (10) times at average. 319 For functions containing one loop with large known number of iterations 320 and other loops having unbounded loops we would end up predicting all 321 the other loops cold that is not usually the case. So we need to artificially 322 flatten the profile. 323 324 We need to cut the maximal predicted iterations to large enought iterations 325 so the loop appears important, but safely within HOT_BB_COUNT_FRACTION 326 range. */ 327 328DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS, 329 "max-predicted-iterations", 330 "The maximum number of loop iterations we predict statically", 331 100, 0, 0) 332DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK, 333 "tracer-dynamic-coverage-feedback", 334 "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available", 335 95, 0, 100) 336DEFPARAM(TRACER_DYNAMIC_COVERAGE, 337 "tracer-dynamic-coverage", 338 "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available", 339 75, 0, 100) 340DEFPARAM(TRACER_MAX_CODE_GROWTH, 341 "tracer-max-code-growth", 342 "Maximal code growth caused by tail duplication (in percent)", 343 100, 0, 0) 344DEFPARAM(TRACER_MIN_BRANCH_RATIO, 345 "tracer-min-branch-ratio", 346 "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent)", 347 10, 0, 100) 348DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK, 349 "tracer-min-branch-probability-feedback", 350 "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available", 351 80, 0, 100) 352DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY, 353 "tracer-min-branch-probability", 354 "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available", 355 50, 0, 100) 356 357/* The maximum number of incoming edges to consider for crossjumping. */ 358DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES, 359 "max-crossjump-edges", 360 "The maximum number of incoming edges to consider for crossjumping", 361 100, 0, 0) 362 363/* The minimum number of matching instructions to consider for crossjumping. */ 364DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS, 365 "min-crossjump-insns", 366 "The minimum number of matching instructions to consider for crossjumping", 367 5, 0, 0) 368 369/* The maximum number expansion factor when copying basic blocks. */ 370DEFPARAM(PARAM_MAX_GROW_COPY_BB_INSNS, 371 "max-grow-copy-bb-insns", 372 "The maximum expansion factor when copying basic blocks", 373 8, 0, 0) 374 375/* The maximum number of insns to duplicate when unfactoring computed gotos. */ 376DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS, 377 "max-goto-duplication-insns", 378 "The maximum number of insns to duplicate when unfactoring computed gotos", 379 8, 0, 0) 380 381/* The maximum length of path considered in cse. */ 382DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH, 383 "max-cse-path-length", 384 "The maximum length of path considered in cse", 385 10, 0, 0) 386DEFPARAM(PARAM_MAX_CSE_INSNS, 387 "max-cse-insns", 388 "The maximum instructions CSE process before flushing", 389 1000, 0, 0) 390 391/* The cost of expression in loop invariant motion that is considered 392 expensive. */ 393DEFPARAM(PARAM_LIM_EXPENSIVE, 394 "lim-expensive", 395 "The minimum cost of an expensive expression in the loop invariant motion", 396 20, 0, 0) 397 398/* Bound on number of candidates for induction variables below that 399 all candidates are considered for each use in induction variable 400 optimizations. */ 401 402DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND, 403 "iv-consider-all-candidates-bound", 404 "Bound on number of candidates below that all candidates are considered in iv optimizations", 405 30, 0, 0) 406 407/* The induction variable optimizations give up on loops that contain more 408 induction variable uses. */ 409 410DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES, 411 "iv-max-considered-uses", 412 "Bound on number of iv uses in loop optimized in iv optimizations", 413 250, 0, 0) 414 415/* If there are at most this number of ivs in the set, try removing unnecessary 416 ivs from the set always. */ 417 418DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND, 419 "iv-always-prune-cand-set-bound", 420 "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization", 421 10, 0, 0) 422 423DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE, 424 "scev-max-expr-size", 425 "Bound on size of expressions used in the scalar evolutions analyzer", 426 20, 0, 0) 427 428DEFPARAM(PARAM_VECT_MAX_VERSION_CHECKS, 429 "vect-max-version-checks", 430 "Bound on number of runtime checks inserted by the vectorizer's loop versioning", 431 6, 0, 0) 432 433/* The product of the next two is used to decide whether or not to 434 use .GLOBAL_VAR. See tree-dfa.c. */ 435DEFPARAM(PARAM_GLOBAL_VAR_THRESHOLD, 436 "global-var-threshold", 437 "Given N calls and V call-clobbered vars in a function. Use .GLOBAL_VAR if NxV is larger than this limit", 438 500000, 0, 0) 439 440DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS, 441 "max-cselib-memory-locations", 442 "The maximum memory locations recorded by cselib", 443 500, 0, 0) 444DEFPARAM(PARAM_MAX_FLOW_MEMORY_LOCATIONS, 445 "max-flow-memory-locations", 446 "The maximum memory locations recorded by flow", 447 100, 0, 0) 448 449#ifdef ENABLE_GC_ALWAYS_COLLECT 450# define GGC_MIN_EXPAND_DEFAULT 0 451# define GGC_MIN_HEAPSIZE_DEFAULT 0 452#else 453# define GGC_MIN_EXPAND_DEFAULT 30 454# define GGC_MIN_HEAPSIZE_DEFAULT 4096 455#endif 456 457DEFPARAM(GGC_MIN_EXPAND, 458 "ggc-min-expand", 459 "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap", 460 GGC_MIN_EXPAND_DEFAULT, 0, 0) 461 462DEFPARAM(GGC_MIN_HEAPSIZE, 463 "ggc-min-heapsize", 464 "Minimum heap size before we start collecting garbage, in kilobytes", 465 GGC_MIN_HEAPSIZE_DEFAULT, 0, 0) 466 467#undef GGC_MIN_EXPAND_DEFAULT 468#undef GGC_MIN_HEAPSIZE_DEFAULT 469 470DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS, 471 "max-reload-search-insns", 472 "The maximum number of instructions to search backward when looking for equivalent reload", 473 100, 0, 0) 474 475DEFPARAM(PARAM_MAX_ALIASED_VOPS, 476 "max-aliased-vops", 477 "The maximum number of virtual operands allowed to represent aliases before triggering alias grouping", 478 500, 0, 0) 479 480DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS, 481 "max-sched-region-blocks", 482 "The maximum number of blocks in a region to be considered for interblock scheduling", 483 10, 0, 0) 484 485DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS, 486 "max-sched-region-insns", 487 "The maximum number of insns in a region to be considered for interblock scheduling", 488 100, 0, 0) 489 490DEFPARAM(PARAM_MIN_SPEC_PROB, 491 "min-spec-prob", 492 "The minimum probability of reaching a source block for interblock speculative scheduling", 493 40, 0, 0) 494 495DEFPARAM(PARAM_MAX_LAST_VALUE_RTL, 496 "max-last-value-rtl", 497 "The maximum number of RTL nodes that can be recorded as combiner's last value", 498 10000, 0, 0) 499 500/* INTEGER_CST nodes are shared for values [{-1,0} .. N) for 501 {signed,unsigned} integral types. This determines N. 502 Experimentation shows 256 to be a good value. */ 503DEFPARAM (PARAM_INTEGER_SHARE_LIMIT, 504 "integer-share-limit", 505 "The upper bound for sharing integer constants", 506 256, 2, 2) 507 508/* Incremental SSA updates for virtual operands may be very slow if 509 there is a large number of mappings to process. In those cases, it 510 is faster to rewrite the virtual symbols from scratch as if they 511 had been recently introduced. This heuristic cannot be applied to 512 SSA mappings for real SSA names, only symbols kept in FUD chains. 513 514 PARAM_MIN_VIRTUAL_MAPPINGS specifies the minimum number of virtual 515 mappings that should be registered to trigger the heuristic. 516 517 PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO specifies the ratio between 518 mappings and symbols. If the number of virtual mappings is 519 PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO bigger than the number of 520 virtual symbols to be updated, then the updater switches to a full 521 update for those symbols. */ 522DEFPARAM (PARAM_MIN_VIRTUAL_MAPPINGS, 523 "min-virtual-mappings", 524 "Minimum number of virtual mappings to consider switching to full virtual renames", 525 100, 0, 0) 526 527DEFPARAM (PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO, 528 "virtual-mappings-ratio", 529 "Ratio between virtual mappings and virtual symbols to do full virtual renames", 530 3, 0, 0) 531 532DEFPARAM (PARAM_SSP_BUFFER_SIZE, 533 "ssp-buffer-size", 534 "The lower bound for a buffer to be considered for stack smashing protection", 535 8, 1, 0) 536 537/* When we thread through a block we have to make copies of the 538 statements within the block. Clearly for large blocks the code 539 duplication is bad. 540 541 PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number 542 of statements and PHI nodes allowed in a block which is going to 543 be duplicated for thread jumping purposes. 544 545 Some simple analysis showed that more than 99% of the jump 546 threading opportunities are for blocks with less than 15 547 statements. So we can get the benefits of jump threading 548 without excessive code bloat for pathological cases with the 549 throttle set at 15 statements. */ 550DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS, 551 "max-jump-thread-duplication-stmts", 552 "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps", 553 15, 0, 0) 554 555/* This is the maximum number of fields a variable may have before the pointer analysis machinery 556 will stop trying to treat it in a field-sensitive manner. 557 There are programs out there with thousands of fields per structure, and handling them 558 field-sensitively is not worth the cost. */ 559DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE, 560 "max-fields-for-field-sensitive", 561 "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable", 562 100, 0, 0) 563 564DEFPARAM(PARAM_MAX_SCHED_READY_INSNS, 565 "max-sched-ready-insns", 566 "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass", 567 100, 0, 0) 568 569/* 570Local variables: 571mode:c 572End: */ 573