gcc/params.def

   1 /* params.def - Run-time parameters.
   2    Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007
   3    Free Software Foundation, Inc.
   4    Written by Mark Mitchell <mark@codesourcery.com>.
   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 /* This file contains definitions for language-independent
  23    parameters.  The DEFPARAM macro takes 6 arguments:
  24
  25      - The enumeral corresponding to this parameter.
  26
  27      - The name that can be used to set this parameter using the
  28        command-line option `--param <name>=<value>'.
  29
  30      - A help string explaining how the parameter is used.
  31
  32      - A default value for the parameter.
  33
  34      - The minimum acceptable value for the parameter.
  35
  36      - The maximum acceptable value for the parameter (if greater than
  37      the minimum).
  38
  39    Be sure to add an entry to invoke.texi summarizing the parameter.  */
  40
  41 /* The maximum structure size at which the scalar replacement of
  42    aggregates (SRA) pass will perform block copies.  The default
  43    value, 0, implies that GCC will select the most appropriate size
  44    itself.  */
  45 DEFPARAM (PARAM_SRA_MAX_STRUCTURE_SIZE,
  46           "sra-max-structure-size",
  47           "The maximum structure size (in bytes) for which GCC will "
  48           "use by-element copies",
  49           0, 0, 0)
  50
  51 /* The maximum number of structure fields which the SRA pass will
  52    instantiate to avoid block copies.  The default value, 0, implies
  53    that GCC will select the appropriate value itself.  */
  54 DEFPARAM (PARAM_SRA_MAX_STRUCTURE_COUNT,
  55           "sra-max-structure-count",
  56           "The maximum number of structure fields for which GCC will "
  57           "use by-element copies",
  58           0, 0, 0)
  59
  60 /* The ratio between instantiated fields and the complete structure
  61    size.  We say that if the ratio of the number of bytes in
  62    instantiated fields to the number of bytes in the complete
  63    structure exceeds this parameter, or if the number of instantiated
  64    fields to the total number of fields exceeds this parameter, then
  65    block copies are not used.  The default is 75%.  */
  66 DEFPARAM (PARAM_SRA_FIELD_STRUCTURE_RATIO,
  67           "sra-field-structure-ratio",
  68           "The threshold ratio between instantiated fields and the total structure size",
  69           75, 0, 100)
  70
  71 /* The threshold ratio between current and hottest structure counts.
  72    We say that if the ratio of the current structure count,
  73    calculated by profiling, to the hottest structure count
  74    in the program is less than this parameter, then structure
  75    reorganization is not applied. The default is 10%.  */
  76 DEFPARAM (PARAM_STRUCT_REORG_COLD_STRUCT_RATIO,
  77           "struct-reorg-cold-struct-ratio",
  78           "The threshold ratio between current and hottest structure counts",
  79           10, 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.  */
  93 DEFPARAM (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.  */
 105 DEFPARAM (PARAM_MAX_INLINE_INSNS_AUTO,
 106           "max-inline-insns-auto",
 107           "The maximum number of instructions when automatically inlining",
 108           90, 0, 0)
 109
 110 DEFPARAM (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
 115 DEFPARAM (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
 120 DEFPARAM (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
 125 DEFPARAM (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
 130 DEFPARAM (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.  */
 137 DEFPARAM (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 /* Limit loop autovectorization to loops with large enough iteration count.  */
 143 DEFPARAM (PARAM_MIN_VECT_LOOP_BOUND,
 144           "min-vect-loop-bound",
 145           "If -ftree-vectorize is used, the minimal loop bound of a loop to be considered for vectorization",
 146           1, 1, 0)
 147
 148 /* The maximum number of instructions to consider when looking for an
 149    instruction to fill a delay slot.  If more than this arbitrary
 150    number of instructions is searched, the time savings from filling
 151    the delay slot will be minimal so stop searching.  Increasing
 152    values mean more aggressive optimization, making the compile time
 153    increase with probably small improvement in executable run time.  */
 154 DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH,
 155           "max-delay-slot-insn-search",
 156           "The maximum number of instructions to consider to fill a delay slot",
 157           100, 0, 0)
 158
 159 /* When trying to fill delay slots, the maximum number of instructions
 160    to consider when searching for a block with valid live register
 161    information.  Increasing this arbitrarily chosen value means more
 162    aggressive optimization, increasing the compile time.  This
 163    parameter should be removed when the delay slot code is rewritten
 164    to maintain the control-flow graph.  */
 165 DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH,
 166          "max-delay-slot-live-search",
 167          "The maximum number of instructions to consider to find accurate live register information",
 168          333, 0, 0)
 169
 170 /* This parameter limits the number of branch elements that the
 171    scheduler will track anti-dependencies through without resetting
 172    the tracking mechanism.  Large functions with few calls or barriers
 173    can generate lists containing many 1000's of dependencies.  Generally
 174    the compiler either uses all available memory, or runs for far too long.  */
 175 DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH,
 176          "max-pending-list-length",
 177          "The maximum length of scheduling's pending operations list",
 178          32, 0, 0)
 179
 180 DEFPARAM(PARAM_LARGE_FUNCTION_INSNS,
 181          "large-function-insns",
 182          "The size of function body to be considered large",
 183          2700, 0, 0)
 184 DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH,
 185          "large-function-growth",
 186          "Maximal growth due to inlining of large function (in percent)",
 187          100, 0, 0)
 188 DEFPARAM(PARAM_LARGE_UNIT_INSNS,
 189          "large-unit-insns",
 190          "The size of translation unit to be considered large",
 191          10000, 0, 0)
 192 DEFPARAM(PARAM_INLINE_UNIT_GROWTH,
 193          "inline-unit-growth",
 194          "how much can given compilation unit grow because of the inlining (in percent)",
 195          30, 0, 0)
 196 DEFPARAM(PARAM_INLINE_CALL_COST,
 197          "inline-call-cost",
 198          "expense of call operation relative to ordinary arithmetic operations",
 199          12, 0, 0)
 200 DEFPARAM(PARAM_LARGE_STACK_FRAME,
 201          "large-stack-frame",
 202          "The size of stack frame to be considered large",
 203          256, 0, 0)
 204 DEFPARAM(PARAM_STACK_FRAME_GROWTH,
 205          "large-stack-frame-growth",
 206          "Maximal stack frame growth due to inlining (in percent)",
 207          1000, 0, 0)
 208
 209 /* The GCSE optimization will be disabled if it would require
 210    significantly more memory than this value.  */
 211 DEFPARAM(PARAM_MAX_GCSE_MEMORY,
 212          "max-gcse-memory",
 213          "The maximum amount of memory to be allocated by GCSE",
 214          50 * 1024 * 1024, 0, 0)
 215 /* The number of repetitions of copy/const prop and PRE to run.  */
 216 DEFPARAM(PARAM_MAX_GCSE_PASSES,
 217         "max-gcse-passes",
 218         "The maximum number of passes to make when doing GCSE",
 219         1, 1, 0)
 220 /* This is the threshold ratio when to perform partial redundancy
 221    elimination after reload. We perform partial redundancy elimination
 222    when the following holds:
 223    (Redundant load execution count)
 224    ------------------------------- >= GCSE_AFTER_RELOAD_PARTIAL_FRACTION
 225    (Added loads execution count)                                          */
 226 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_PARTIAL_FRACTION,
 227         "gcse-after-reload-partial-fraction",
 228         "The threshold ratio for performing partial redundancy elimination after reload",
 229         3, 0, 0)
 230 /* This is the threshold ratio of the critical edges execution count compared to
 231    the redundant loads execution count that permits performing the load
 232    redundancy elimination in gcse after reload.  */
 233 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_CRITICAL_FRACTION,
 234         "gcse-after-reload-critical-fraction",
 235         "The threshold ratio of critical edges execution count that permit performing redundancy elimination after reload",
 236         10, 0, 0)
 237 /* This parameter limits the number of insns in a loop that will be unrolled,
 238    and by how much the loop is unrolled.
 239
 240    This limit should be at most half of the peeling limits:  loop unroller
 241    decides to not unroll loops that iterate fewer than 2*number of allowed
 242    unrollings and thus we would have loops that are neither peeled or unrolled
 243    otherwise.  */
 244 DEFPARAM(PARAM_MAX_UNROLLED_INSNS,
 245          "max-unrolled-insns",
 246          "The maximum number of instructions to consider to unroll in a loop",
 247          200, 0, 0)
 248 /* This parameter limits how many times the loop is unrolled depending
 249    on number of insns really executed in each iteration.  */
 250 DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS,
 251          "max-average-unrolled-insns",
 252          "The maximum number of instructions to consider to unroll in a loop on average",
 253          80, 0, 0)
 254 /* The maximum number of unrollings of a single loop.  */
 255 DEFPARAM(PARAM_MAX_UNROLL_TIMES,
 256         "max-unroll-times",
 257         "The maximum number of unrollings of a single loop",
 258         8, 0, 0)
 259 /* The maximum number of insns of a peeled loop.  */
 260 DEFPARAM(PARAM_MAX_PEELED_INSNS,
 261         "max-peeled-insns",
 262         "The maximum number of insns of a peeled loop",
 263         400, 0, 0)
 264 /* The maximum number of peelings of a single loop.  */
 265 DEFPARAM(PARAM_MAX_PEEL_TIMES,
 266         "max-peel-times",
 267         "The maximum number of peelings of a single loop",
 268         16, 0, 0)
 269 /* The maximum number of insns of a peeled loop.  */
 270 DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS,
 271         "max-completely-peeled-insns",
 272         "The maximum number of insns of a completely peeled loop",
 273         400, 0, 0)
 274 /* The maximum number of peelings of a single loop that is peeled completely.  */
 275 DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES,
 276         "max-completely-peel-times",
 277         "The maximum number of peelings of a single loop that is peeled completely",
 278         16, 0, 0)
 279 /* The maximum number of insns of a peeled loop that rolls only once.  */
 280 DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS,
 281         "max-once-peeled-insns",
 282         "The maximum number of insns of a peeled loop that rolls only once",
 283         400, 0, 0)
 284
 285 /* The maximum number of insns of an unswitched loop.  */
 286 DEFPARAM(PARAM_MAX_UNSWITCH_INSNS,
 287         "max-unswitch-insns",
 288         "The maximum number of insns of an unswitched loop",
 289         50, 0, 0)
 290 /* The maximum level of recursion in unswitch_single_loop.  */
 291 DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL,
 292         "max-unswitch-level",
 293         "The maximum number of unswitchings in a single loop",
 294         3, 0, 0)
 295
 296 /* The maximum number of iterations of a loop the brute force algorithm
 297    for analysis of # of iterations of the loop tries to evaluate.  */
 298 DEFPARAM(PARAM_MAX_ITERATIONS_TO_TRACK,
 299         "max-iterations-to-track",
 300         "Bound on the number of iterations the brute force # of iterations analysis algorithm evaluates",
 301         1000, 0, 0)
 302 /* A cutoff to avoid costly computations of the number of iterations in
 303    the doloop transformation.  */
 304 DEFPARAM(PARAM_MAX_ITERATIONS_COMPUTATION_COST,
 305         "max-iterations-computation-cost",
 306         "Bound on the cost of an expression to compute the number of iterations",
 307         10, 0, 0)
 308
 309 /* This parameter is used to tune SMS MAX II calculations.  */
 310 DEFPARAM(PARAM_SMS_MAX_II_FACTOR,
 311          "sms-max-ii-factor",
 312          "A factor for tuning the upper bound that swing modulo scheduler uses for scheduling a loop",
 313          100, 0, 0)
 314 DEFPARAM(PARAM_SMS_DFA_HISTORY,
 315          "sms-dfa-history",
 316          "The number of cycles the swing modulo scheduler considers when checking conflicts using DFA",
 317          0, 0, 0)
 318 DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD,
 319          "sms-loop-average-count-threshold",
 320          "A threshold on the average loop count considered by the swing modulo scheduler",
 321          0, 0, 0)
 322
 323 DEFPARAM(HOT_BB_COUNT_FRACTION,
 324          "hot-bb-count-fraction",
 325          "Select fraction of the maximal count of repetitions of basic block in program given basic block needs to have to be considered hot",
 326          10000, 0, 0)
 327 DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
 328          "hot-bb-frequency-fraction",
 329          "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot",
 330          1000, 0, 0)
 331
 332 DEFPARAM (PARAM_ALIGN_THRESHOLD,
 333           "align-threshold",
 334           "Select fraction of the maximal frequency of executions of basic block in function given basic block get alignment",
 335           100, 0, 0)
 336
 337 DEFPARAM (PARAM_ALIGN_LOOP_ITERATIONS,
 338           "align-loop-iterations",
 339           "Loops iterating at least selected number of iterations will get loop alignement.",
 340           4, 0, 0)
 341
 342 /* For guessed profiles, the loops having unknown number of iterations
 343    are predicted to iterate relatively few (10) times at average.
 344    For functions containing one loop with large known number of iterations
 345    and other loops having unbounded loops we would end up predicting all
 346    the other loops cold that is not usually the case.  So we need to artificially
 347    flatten the profile.
 348
 349    We need to cut the maximal predicted iterations to large enough iterations
 350    so the loop appears important, but safely within HOT_BB_COUNT_FRACTION
 351    range.  */
 352
 353 DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS,
 354          "max-predicted-iterations",
 355          "The maximum number of loop iterations we predict statically",
 356          100, 0, 0)
 357 DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
 358          "tracer-dynamic-coverage-feedback",
 359          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available",
 360          95, 0, 100)
 361 DEFPARAM(TRACER_DYNAMIC_COVERAGE,
 362          "tracer-dynamic-coverage",
 363          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available",
 364          75, 0, 100)
 365 DEFPARAM(TRACER_MAX_CODE_GROWTH,
 366          "tracer-max-code-growth",
 367          "Maximal code growth caused by tail duplication (in percent)",
 368          100, 0, 0)
 369 DEFPARAM(TRACER_MIN_BRANCH_RATIO,
 370          "tracer-min-branch-ratio",
 371          "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent)",
 372          10, 0, 100)
 373 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
 374          "tracer-min-branch-probability-feedback",
 375          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available",
 376          80, 0, 100)
 377 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
 378          "tracer-min-branch-probability",
 379          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available",
 380          50, 0, 100)
 381
 382 /* The maximum number of incoming edges to consider for crossjumping.  */
 383 DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
 384          "max-crossjump-edges",
 385          "The maximum number of incoming edges to consider for crossjumping",
 386          100, 0, 0)
 387
 388 /* The minimum number of matching instructions to consider for crossjumping.  */
 389 DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS,
 390      "min-crossjump-insns",
 391      "The minimum number of matching instructions to consider for crossjumping",
 392      5, 0, 0)
 393
 394 /* The maximum number expansion factor when copying basic blocks.  */
 395 DEFPARAM(PARAM_MAX_GROW_COPY_BB_INSNS,
 396      "max-grow-copy-bb-insns",
 397      "The maximum expansion factor when copying basic blocks",
 398      8, 0, 0)
 399
 400 /* The maximum number of insns to duplicate when unfactoring computed gotos.  */
 401 DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS,
 402      "max-goto-duplication-insns",
 403      "The maximum number of insns to duplicate when unfactoring computed gotos",
 404      8, 0, 0)
 405
 406 /* The maximum length of path considered in cse.  */
 407 DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
 408          "max-cse-path-length",
 409          "The maximum length of path considered in cse",
 410          10, 0, 0)
 411 DEFPARAM(PARAM_MAX_CSE_INSNS,
 412          "max-cse-insns",
 413          "The maximum instructions CSE process before flushing",
 414          1000, 0, 0)
 415
 416 /* The cost of expression in loop invariant motion that is considered
 417    expensive.  */
 418 DEFPARAM(PARAM_LIM_EXPENSIVE,
 419          "lim-expensive",
 420          "The minimum cost of an expensive expression in the loop invariant motion",
 421          20, 0, 0)
 422
 423 /* Bound on number of candidates for induction variables below that
 424    all candidates are considered for each use in induction variable
 425    optimizations.  */
 426
 427 DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND,
 428          "iv-consider-all-candidates-bound",
 429          "Bound on number of candidates below that all candidates are considered in iv optimizations",
 430          30, 0, 0)
 431
 432 /* The induction variable optimizations give up on loops that contain more
 433    induction variable uses.  */
 434
 435 DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES,
 436          "iv-max-considered-uses",
 437          "Bound on number of iv uses in loop optimized in iv optimizations",
 438          250, 0, 0)
 439
 440 /* If there are at most this number of ivs in the set, try removing unnecessary
 441    ivs from the set always.  */
 442
 443 DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND,
 444          "iv-always-prune-cand-set-bound",
 445          "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization",
 446          10, 0, 0)
 447
 448 DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE,
 449          "scev-max-expr-size",
 450          "Bound on size of expressions used in the scalar evolutions analyzer",
 451          20, 0, 0)
 452
 453 DEFPARAM(PARAM_OMEGA_MAX_VARS,
 454          "omega-max-vars",
 455          "Bound on the number of variables in Omega constraint systems",
 456          128, 0, 0)
 457
 458 DEFPARAM(PARAM_OMEGA_MAX_GEQS,
 459          "omega-max-geqs",
 460          "Bound on the number of inequalities in Omega constraint systems",
 461          256, 0, 0)
 462
 463 DEFPARAM(PARAM_OMEGA_MAX_EQS,
 464          "omega-max-eqs",
 465          "Bound on the number of equalities in Omega constraint systems",
 466          128, 0, 0)
 467
 468 DEFPARAM(PARAM_OMEGA_MAX_WILD_CARDS,
 469          "omega-max-wild-cards",
 470          "Bound on the number of wild cards in Omega constraint systems",
 471          18, 0, 0)
 472
 473 DEFPARAM(PARAM_OMEGA_HASH_TABLE_SIZE,
 474          "omega-hash-table-size",
 475          "Bound on the size of the hash table in Omega constraint systems",
 476          550, 0, 0)
 477
 478 DEFPARAM(PARAM_OMEGA_MAX_KEYS,
 479          "omega-max-keys",
 480          "Bound on the number of keys in Omega constraint systems",
 481          500, 0, 0)
 482
 483 DEFPARAM(PARAM_OMEGA_ELIMINATE_REDUNDANT_CONSTRAINTS,
 484          "omega-eliminate-redundant-constraints",
 485          "When set to 1, use expensive methods to eliminate all redundant constraints",
 486          0, 0, 1)
 487
 488 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIGNMENT_CHECKS,
 489          "vect-max-version-for-alignment-checks",
 490          "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alignment check",
 491          6, 0, 0)
 492
 493 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS,
 494          "vect-max-version-for-alias-checks",
 495          "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alias check",
 496          10, 0, 0)
 497
 498 DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS,
 499          "max-cselib-memory-locations",
 500          "The maximum memory locations recorded by cselib",
 501          500, 0, 0)
 502
 503 #ifdef ENABLE_GC_ALWAYS_COLLECT
 504 # define GGC_MIN_EXPAND_DEFAULT 0
 505 # define GGC_MIN_HEAPSIZE_DEFAULT 0
 506 #else
 507 # define GGC_MIN_EXPAND_DEFAULT 30
 508 # define GGC_MIN_HEAPSIZE_DEFAULT 4096
 509 #endif
 510
 511 DEFPARAM(GGC_MIN_EXPAND,
 512          "ggc-min-expand",
 513          "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap",
 514          GGC_MIN_EXPAND_DEFAULT, 0, 0)
 515
 516 DEFPARAM(GGC_MIN_HEAPSIZE,
 517          "ggc-min-heapsize",
 518          "Minimum heap size before we start collecting garbage, in kilobytes",
 519          GGC_MIN_HEAPSIZE_DEFAULT, 0, 0)
 520
 521 #undef GGC_MIN_EXPAND_DEFAULT
 522 #undef GGC_MIN_HEAPSIZE_DEFAULT
 523
 524 DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
 525          "max-reload-search-insns",
 526          "The maximum number of instructions to search backward when looking for equivalent reload",
 527          100, 0, 0)
 528
 529 DEFPARAM(PARAM_MAX_ALIASED_VOPS,
 530          "max-aliased-vops",
 531          "The maximum number of virtual operators that a function is allowed to have before triggering memory partitioning heuristics",
 532          100, 0, 0)
 533
 534 DEFPARAM(PARAM_AVG_ALIASED_VOPS,
 535          "avg-aliased-vops",
 536          "The average number of virtual operators that memory statements are allowed to have before triggering memory partitioning heuristics",
 537          1, 0, 0)
 538
 539 DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS,
 540          "max-sched-region-blocks",
 541          "The maximum number of blocks in a region to be considered for interblock scheduling",
 542          10, 0, 0)
 543
 544 DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS,
 545          "max-sched-region-insns",
 546          "The maximum number of insns in a region to be considered for interblock scheduling",
 547          100, 0, 0)
 548
 549 DEFPARAM(PARAM_MIN_SPEC_PROB,
 550          "min-spec-prob",
 551          "The minimum probability of reaching a source block for interblock speculative scheduling",
 552          40, 0, 0)
 553
 554 DEFPARAM(PARAM_MAX_SCHED_EXTEND_REGIONS_ITERS,
 555          "max-sched-extend-regions-iters",
 556          "The maximum number of iterations through CFG to extend regions",
 557          0, 0, 0)
 558
 559 DEFPARAM(PARAM_MAX_SCHED_INSN_CONFLICT_DELAY,
 560          "max-sched-insn-conflict-delay",
 561          "The maximum conflict delay for an insn to be considered for speculative motion",
 562          3, 1, 10)
 563
 564 DEFPARAM(PARAM_SCHED_SPEC_PROB_CUTOFF,
 565          "sched-spec-prob-cutoff",
 566          "The minimal probability of speculation success (in percents), so that speculative insn will be scheduled.",
 567          40, 0, 100)
 568
 569 DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
 570          "max-last-value-rtl",
 571          "The maximum number of RTL nodes that can be recorded as combiner's last value",
 572          10000, 0, 0)
 573
 574 /* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
 575    {signed,unsigned} integral types.  This determines N.
 576    Experimentation shows 256 to be a good value.  */
 577 DEFPARAM (PARAM_INTEGER_SHARE_LIMIT,
 578           "integer-share-limit",
 579           "The upper bound for sharing integer constants",
 580           256, 2, 2)
 581
 582 /* Incremental SSA updates for virtual operands may be very slow if
 583    there is a large number of mappings to process.  In those cases, it
 584    is faster to rewrite the virtual symbols from scratch as if they
 585    had been recently introduced.  This heuristic cannot be applied to
 586    SSA mappings for real SSA names, only symbols kept in FUD chains.
 587
 588    PARAM_MIN_VIRTUAL_MAPPINGS specifies the minimum number of virtual
 589    mappings that should be registered to trigger the heuristic.
 590
 591    PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO specifies the ratio between
 592    mappings and symbols.  If the number of virtual mappings is
 593    PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO bigger than the number of
 594    virtual symbols to be updated, then the updater switches to a full
 595    update for those symbols.  */
 596 DEFPARAM (PARAM_MIN_VIRTUAL_MAPPINGS,
 597           "min-virtual-mappings",
 598           "Minimum number of virtual mappings to consider switching to full virtual renames",
 599           100, 0, 0)
 600
 601 DEFPARAM (PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO,
 602           "virtual-mappings-ratio",
 603           "Ratio between virtual mappings and virtual symbols to do full virtual renames",
 604           3, 0, 0)
 605
 606 DEFPARAM (PARAM_SSP_BUFFER_SIZE,
 607           "ssp-buffer-size",
 608           "The lower bound for a buffer to be considered for stack smashing protection",
 609           8, 1, 0)
 610
 611 /* When we thread through a block we have to make copies of the
 612    statements within the block.  Clearly for large blocks the code
 613    duplication is bad.
 614
 615    PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number
 616    of statements and PHI nodes allowed in a block which is going to
 617    be duplicated for thread jumping purposes.
 618
 619    Some simple analysis showed that more than 99% of the jump
 620    threading opportunities are for blocks with less than 15
 621    statements.  So we can get the benefits of jump threading
 622    without excessive code bloat for pathological cases with the
 623    throttle set at 15 statements.  */
 624 DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS,
 625           "max-jump-thread-duplication-stmts",
 626           "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps",
 627           15, 0, 0)
 628
 629 /* This is the maximum number of fields a variable may have before the pointer analysis machinery
 630    will stop trying to treat it in a field-sensitive manner.
 631    There are programs out there with thousands of fields per structure, and handling them
 632    field-sensitively is not worth the cost.  */
 633 DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE,
 634           "max-fields-for-field-sensitive",
 635           "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable",
 636           0, 0, 0)
 637
 638 DEFPARAM(PARAM_MAX_SCHED_READY_INSNS,
 639          "max-sched-ready-insns",
 640          "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass",
 641          100, 0, 0)
 642
 643 /* Prefetching and cache-optimizations related parameters.  Default values are
 644    usually set by machine description.  */
 645
 646 /* The number of insns executed before prefetch is completed.  */
 647
 648 DEFPARAM (PARAM_PREFETCH_LATENCY,
 649          "prefetch-latency",
 650          "The number of insns executed before prefetch is completed",
 651          200, 0, 0)
 652
 653 /* The number of prefetches that can run at the same time.  */
 654
 655 DEFPARAM (PARAM_SIMULTANEOUS_PREFETCHES,
 656           "simultaneous-prefetches",
 657           "The number of prefetches that can run at the same time",
 658           3, 0, 0)
 659
 660 /* The size of L1 cache in kB.  */
 661
 662 DEFPARAM (PARAM_L1_CACHE_SIZE,
 663           "l1-cache-size",
 664           "The size of L1 cache",
 665           64, 0, 0)
 666
 667 /* The size of L1 cache line in bytes.  */
 668
 669 DEFPARAM (PARAM_L1_CACHE_LINE_SIZE,
 670           "l1-cache-line-size",
 671           "The size of L1 cache line",
 672           32, 0, 0)
 673
 674 /* The size of L2 cache in kB.  */
 675
 676 DEFPARAM (PARAM_L2_CACHE_SIZE,
 677           "l2-cache-size",
 678           "The size of L2 cache",
 679           512, 0, 0)
 680
 681 /* Whether we should use canonical types rather than deep "structural"
 682    type checking.  Setting this value to 1 (the default) improves
 683    compilation performance in the C++ and Objective-C++ front end;
 684    this value should only be set to zero to work around bugs in the
 685    canonical type system by disabling it.  */
 686
 687 DEFPARAM (PARAM_USE_CANONICAL_TYPES,
 688           "use-canonical-types",
 689           "Whether to use canonical types",
 690           1, 0, 1)
 691
 692 DEFPARAM (PARAM_MAX_PARTIAL_ANTIC_LENGTH,
 693           "max-partial-antic-length",
 694           "Maximum length of partial antic set when performing tree pre optimization",
 695           100, 0, 0)
 696
 697 /* The following is used as a stop-gap limit for cases where really huge
 698    SCCs blow up memory and compile-time use too much.  If we hit this limit,
 699    SCCVN and such FRE and PRE will be not done at all for the current
 700    function.  */
 701
 702 DEFPARAM (PARAM_SCCVN_MAX_SCC_SIZE,
 703           "sccvn-max-scc-size",
 704           "Maximum size of a SCC before SCCVN stops processing a function",
 705           10000, 10, 0)
 706
 707
 708 DEFPARAM (PARAM_DF_DOUBLE_QUEUE_THRESHOLD_FACTOR,
 709           "df-double-queue-threshold-factor",
 710           "Multiplier used for determining the double-queueing threshold",
 711           2, 0, 0)
 712
 713 DEFPARAM (PARAM_IRA_MAX_LOOPS_NUM,
 714           "ira-max-loops-num",
 715           "max loops number for regional RA",
 716           50, 0, 0)
 717
 718 /*
 719 Local variables:
 720 mode:c
 721 End:
 722 */