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 /* When branch is predicted to be taken with probability lower than this
  82    threshold (in percent), then it is considered well predictable. */
  83 DEFPARAM (PARAM_PREDICTABLE_BRANCH_OUTCOME,
  84           "predictable-branch-outcome",
  85           "Maximal esitmated outcome of branch considered predictable",
  86           2, 0, 50)
  87
  88 /* The single function inlining limit. This is the maximum size
  89    of a function counted in internal gcc instructions (not in
  90    real machine instructions) that is eligible for inlining
  91    by the tree inliner.
  92    The default value is 450.
  93    Only functions marked inline (or methods defined in the class
  94    definition for C++) are affected by this.
  95    There are more restrictions to inlining: If inlined functions
  96    call other functions, the already inlined instructions are
  97    counted and once the recursive inline limit (see
  98    "max-inline-insns" parameter) is exceeded, the acceptable size
  99    gets decreased.  */
 100 DEFPARAM (PARAM_MAX_INLINE_INSNS_SINGLE,
 101           "max-inline-insns-single",
 102           "The maximum number of instructions in a single function eligible for inlining",
 103           450, 0, 0)
 104
 105 /* The single function inlining limit for functions that are
 106    inlined by virtue of -finline-functions (-O3).
 107    This limit should be chosen to be below or equal to the limit
 108    that is applied to functions marked inlined (or defined in the
 109    class declaration in C++) given by the "max-inline-insns-single"
 110    parameter.
 111    The default value is 90.  */
 112 DEFPARAM (PARAM_MAX_INLINE_INSNS_AUTO,
 113           "max-inline-insns-auto",
 114           "The maximum number of instructions when automatically inlining",
 115           90, 0, 0)
 116
 117 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE,
 118           "max-inline-insns-recursive",
 119           "The maximum number of instructions inline function can grow to via recursive inlining",
 120           450, 0, 0)
 121
 122 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO,
 123           "max-inline-insns-recursive-auto",
 124           "The maximum number of instructions non-inline function can grow to via recursive inlining",
 125           450, 0, 0)
 126
 127 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH,
 128           "max-inline-recursive-depth",
 129           "The maximum depth of recursive inlining for inline functions",
 130           8, 0, 0)
 131
 132 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO,
 133           "max-inline-recursive-depth-auto",
 134           "The maximum depth of recursive inlining for non-inline functions",
 135           8, 0, 0)
 136
 137 DEFPARAM (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY,
 138           "min-inline-recursive-probability",
 139           "Inline recursively only when the probability of call being executed exceeds the parameter",
 140           10, 0, 0)
 141
 142 /* Limit the number of expansions created by the variable expansion
 143    optimization to avoid register pressure.  */
 144 DEFPARAM (PARAM_MAX_VARIABLE_EXPANSIONS,
 145           "max-variable-expansions-in-unroller",
 146           "If -fvariable-expansion-in-unroller is used, the maximum number of times that an individual variable will be expanded during loop unrolling",
 147           1, 0, 0)
 148
 149 /* Limit loop autovectorization to loops with large enough iteration count.  */
 150 DEFPARAM (PARAM_MIN_VECT_LOOP_BOUND,
 151           "min-vect-loop-bound",
 152           "If -ftree-vectorize is used, the minimal loop bound of a loop to be considered for vectorization",
 153           1, 1, 0)
 154
 155 /* The maximum number of instructions to consider when looking for an
 156    instruction to fill a delay slot.  If more than this arbitrary
 157    number of instructions is searched, the time savings from filling
 158    the delay slot will be minimal so stop searching.  Increasing
 159    values mean more aggressive optimization, making the compile time
 160    increase with probably small improvement in executable run time.  */
 161 DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH,
 162           "max-delay-slot-insn-search",
 163           "The maximum number of instructions to consider to fill a delay slot",
 164           100, 0, 0)
 165
 166 /* When trying to fill delay slots, the maximum number of instructions
 167    to consider when searching for a block with valid live register
 168    information.  Increasing this arbitrarily chosen value means more
 169    aggressive optimization, increasing the compile time.  This
 170    parameter should be removed when the delay slot code is rewritten
 171    to maintain the control-flow graph.  */
 172 DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH,
 173          "max-delay-slot-live-search",
 174          "The maximum number of instructions to consider to find accurate live register information",
 175          333, 0, 0)
 176
 177 /* This parameter limits the number of branch elements that the
 178    scheduler will track anti-dependencies through without resetting
 179    the tracking mechanism.  Large functions with few calls or barriers
 180    can generate lists containing many 1000's of dependencies.  Generally
 181    the compiler either uses all available memory, or runs for far too long.  */
 182 DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH,
 183          "max-pending-list-length",
 184          "The maximum length of scheduling's pending operations list",
 185          32, 0, 0)
 186
 187 DEFPARAM(PARAM_LARGE_FUNCTION_INSNS,
 188          "large-function-insns",
 189          "The size of function body to be considered large",
 190          2700, 0, 0)
 191 DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH,
 192          "large-function-growth",
 193          "Maximal growth due to inlining of large function (in percent)",
 194          100, 0, 0)
 195 DEFPARAM(PARAM_LARGE_UNIT_INSNS,
 196          "large-unit-insns",
 197          "The size of translation unit to be considered large",
 198          10000, 0, 0)
 199 DEFPARAM(PARAM_INLINE_UNIT_GROWTH,
 200          "inline-unit-growth",
 201          "how much can given compilation unit grow because of the inlining (in percent)",
 202          30, 0, 0)
 203 DEFPARAM(PARAM_IPCP_UNIT_GROWTH,
 204          "ipcp-unit-growth",
 205          "how much can given compilation unit grow because of the interprocedural constant propagation (in percent)",
 206          10, 0, 0)
 207 DEFPARAM(PARAM_INLINE_CALL_COST,
 208          "inline-call-cost",
 209          "expense of call operation relative to ordinary arithmetic operations",
 210          12, 0, 0)
 211 DEFPARAM(PARAM_LARGE_STACK_FRAME,
 212          "large-stack-frame",
 213          "The size of stack frame to be considered large",
 214          256, 0, 0)
 215 DEFPARAM(PARAM_STACK_FRAME_GROWTH,
 216          "large-stack-frame-growth",
 217          "Maximal stack frame growth due to inlining (in percent)",
 218          1000, 0, 0)
 219
 220 /* The GCSE optimization will be disabled if it would require
 221    significantly more memory than this value.  */
 222 DEFPARAM(PARAM_MAX_GCSE_MEMORY,
 223          "max-gcse-memory",
 224          "The maximum amount of memory to be allocated by GCSE",
 225          50 * 1024 * 1024, 0, 0)
 226 /* The number of repetitions of copy/const prop and PRE to run.  */
 227 DEFPARAM(PARAM_MAX_GCSE_PASSES,
 228         "max-gcse-passes",
 229         "The maximum number of passes to make when doing GCSE",
 230         1, 1, 0)
 231 /* This is the threshold ratio when to perform partial redundancy
 232    elimination after reload. We perform partial redundancy elimination
 233    when the following holds:
 234    (Redundant load execution count)
 235    ------------------------------- >= GCSE_AFTER_RELOAD_PARTIAL_FRACTION
 236    (Added loads execution count)                                          */
 237 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_PARTIAL_FRACTION,
 238         "gcse-after-reload-partial-fraction",
 239         "The threshold ratio for performing partial redundancy elimination after reload",
 240         3, 0, 0)
 241 /* This is the threshold ratio of the critical edges execution count compared to
 242    the redundant loads execution count that permits performing the load
 243    redundancy elimination in gcse after reload.  */
 244 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_CRITICAL_FRACTION,
 245         "gcse-after-reload-critical-fraction",
 246         "The threshold ratio of critical edges execution count that permit performing redundancy elimination after reload",
 247         10, 0, 0)
 248 /* This parameter limits the number of insns in a loop that will be unrolled,
 249    and by how much the loop is unrolled.
 250
 251    This limit should be at most half of the peeling limits:  loop unroller
 252    decides to not unroll loops that iterate fewer than 2*number of allowed
 253    unrollings and thus we would have loops that are neither peeled or unrolled
 254    otherwise.  */
 255 DEFPARAM(PARAM_MAX_UNROLLED_INSNS,
 256          "max-unrolled-insns",
 257          "The maximum number of instructions to consider to unroll in a loop",
 258          200, 0, 0)
 259 /* This parameter limits how many times the loop is unrolled depending
 260    on number of insns really executed in each iteration.  */
 261 DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS,
 262          "max-average-unrolled-insns",
 263          "The maximum number of instructions to consider to unroll in a loop on average",
 264          80, 0, 0)
 265 /* The maximum number of unrollings of a single loop.  */
 266 DEFPARAM(PARAM_MAX_UNROLL_TIMES,
 267         "max-unroll-times",
 268         "The maximum number of unrollings of a single loop",
 269         8, 0, 0)
 270 /* The maximum number of insns of a peeled loop.  */
 271 DEFPARAM(PARAM_MAX_PEELED_INSNS,
 272         "max-peeled-insns",
 273         "The maximum number of insns of a peeled loop",
 274         400, 0, 0)
 275 /* The maximum number of peelings of a single loop.  */
 276 DEFPARAM(PARAM_MAX_PEEL_TIMES,
 277         "max-peel-times",
 278         "The maximum number of peelings of a single loop",
 279         16, 0, 0)
 280 /* The maximum number of insns of a peeled loop.  */
 281 DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS,
 282         "max-completely-peeled-insns",
 283         "The maximum number of insns of a completely peeled loop",
 284         400, 0, 0)
 285 /* The maximum number of peelings of a single loop that is peeled completely.  */
 286 DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES,
 287         "max-completely-peel-times",
 288         "The maximum number of peelings of a single loop that is peeled completely",
 289         16, 0, 0)
 290 /* The maximum number of insns of a peeled loop that rolls only once.  */
 291 DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS,
 292         "max-once-peeled-insns",
 293         "The maximum number of insns of a peeled loop that rolls only once",
 294         400, 0, 0)
 295
 296 /* The maximum number of insns of an unswitched loop.  */
 297 DEFPARAM(PARAM_MAX_UNSWITCH_INSNS,
 298         "max-unswitch-insns",
 299         "The maximum number of insns of an unswitched loop",
 300         50, 0, 0)
 301 /* The maximum level of recursion in unswitch_single_loop.  */
 302 DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL,
 303         "max-unswitch-level",
 304         "The maximum number of unswitchings in a single loop",
 305         3, 0, 0)
 306
 307 /* The maximum number of iterations of a loop the brute force algorithm
 308    for analysis of # of iterations of the loop tries to evaluate.  */
 309 DEFPARAM(PARAM_MAX_ITERATIONS_TO_TRACK,
 310         "max-iterations-to-track",
 311         "Bound on the number of iterations the brute force # of iterations analysis algorithm evaluates",
 312         1000, 0, 0)
 313 /* A cutoff to avoid costly computations of the number of iterations in
 314    the doloop transformation.  */
 315 DEFPARAM(PARAM_MAX_ITERATIONS_COMPUTATION_COST,
 316         "max-iterations-computation-cost",
 317         "Bound on the cost of an expression to compute the number of iterations",
 318         10, 0, 0)
 319
 320 /* This parameter is used to tune SMS MAX II calculations.  */
 321 DEFPARAM(PARAM_SMS_MAX_II_FACTOR,
 322          "sms-max-ii-factor",
 323          "A factor for tuning the upper bound that swing modulo scheduler uses for scheduling a loop",
 324          100, 0, 0)
 325 DEFPARAM(PARAM_SMS_DFA_HISTORY,
 326          "sms-dfa-history",
 327          "The number of cycles the swing modulo scheduler considers when checking conflicts using DFA",
 328          0, 0, 0)
 329 DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD,
 330          "sms-loop-average-count-threshold",
 331          "A threshold on the average loop count considered by the swing modulo scheduler",
 332          0, 0, 0)
 333
 334 DEFPARAM(HOT_BB_COUNT_FRACTION,
 335          "hot-bb-count-fraction",
 336          "Select fraction of the maximal count of repetitions of basic block in program given basic block needs to have to be considered hot",
 337          10000, 0, 0)
 338 DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
 339          "hot-bb-frequency-fraction",
 340          "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot",
 341          1000, 0, 0)
 342
 343 DEFPARAM (PARAM_ALIGN_THRESHOLD,
 344           "align-threshold",
 345           "Select fraction of the maximal frequency of executions of basic block in function given basic block get alignment",
 346           100, 0, 0)
 347
 348 DEFPARAM (PARAM_ALIGN_LOOP_ITERATIONS,
 349           "align-loop-iterations",
 350           "Loops iterating at least selected number of iterations will get loop alignement.",
 351           4, 0, 0)
 352
 353 /* For guessed profiles, the loops having unknown number of iterations
 354    are predicted to iterate relatively few (10) times at average.
 355    For functions containing one loop with large known number of iterations
 356    and other loops having unbounded loops we would end up predicting all
 357    the other loops cold that is not usually the case.  So we need to artificially
 358    flatten the profile.
 359
 360    We need to cut the maximal predicted iterations to large enough iterations
 361    so the loop appears important, but safely within HOT_BB_COUNT_FRACTION
 362    range.  */
 363
 364 DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS,
 365          "max-predicted-iterations",
 366          "The maximum number of loop iterations we predict statically",
 367          100, 0, 0)
 368 DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
 369          "tracer-dynamic-coverage-feedback",
 370          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available",
 371          95, 0, 100)
 372 DEFPARAM(TRACER_DYNAMIC_COVERAGE,
 373          "tracer-dynamic-coverage",
 374          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available",
 375          75, 0, 100)
 376 DEFPARAM(TRACER_MAX_CODE_GROWTH,
 377          "tracer-max-code-growth",
 378          "Maximal code growth caused by tail duplication (in percent)",
 379          100, 0, 0)
 380 DEFPARAM(TRACER_MIN_BRANCH_RATIO,
 381          "tracer-min-branch-ratio",
 382          "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent)",
 383          10, 0, 100)
 384 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
 385          "tracer-min-branch-probability-feedback",
 386          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available",
 387          80, 0, 100)
 388 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
 389          "tracer-min-branch-probability",
 390          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available",
 391          50, 0, 100)
 392
 393 /* The maximum number of incoming edges to consider for crossjumping.  */
 394 DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
 395          "max-crossjump-edges",
 396          "The maximum number of incoming edges to consider for crossjumping",
 397          100, 0, 0)
 398
 399 /* The minimum number of matching instructions to consider for crossjumping.  */
 400 DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS,
 401      "min-crossjump-insns",
 402      "The minimum number of matching instructions to consider for crossjumping",
 403      5, 0, 0)
 404
 405 /* The maximum number expansion factor when copying basic blocks.  */
 406 DEFPARAM(PARAM_MAX_GROW_COPY_BB_INSNS,
 407      "max-grow-copy-bb-insns",
 408      "The maximum expansion factor when copying basic blocks",
 409      8, 0, 0)
 410
 411 /* The maximum number of insns to duplicate when unfactoring computed gotos.  */
 412 DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS,
 413      "max-goto-duplication-insns",
 414      "The maximum number of insns to duplicate when unfactoring computed gotos",
 415      8, 0, 0)
 416
 417 /* The maximum length of path considered in cse.  */
 418 DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
 419          "max-cse-path-length",
 420          "The maximum length of path considered in cse",
 421          10, 0, 0)
 422 DEFPARAM(PARAM_MAX_CSE_INSNS,
 423          "max-cse-insns",
 424          "The maximum instructions CSE process before flushing",
 425          1000, 0, 0)
 426
 427 /* The cost of expression in loop invariant motion that is considered
 428    expensive.  */
 429 DEFPARAM(PARAM_LIM_EXPENSIVE,
 430          "lim-expensive",
 431          "The minimum cost of an expensive expression in the loop invariant motion",
 432          20, 0, 0)
 433
 434 /* Bound on number of candidates for induction variables below that
 435    all candidates are considered for each use in induction variable
 436    optimizations.  */
 437
 438 DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND,
 439          "iv-consider-all-candidates-bound",
 440          "Bound on number of candidates below that all candidates are considered in iv optimizations",
 441          30, 0, 0)
 442
 443 /* The induction variable optimizations give up on loops that contain more
 444    induction variable uses.  */
 445
 446 DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES,
 447          "iv-max-considered-uses",
 448          "Bound on number of iv uses in loop optimized in iv optimizations",
 449          250, 0, 0)
 450
 451 /* If there are at most this number of ivs in the set, try removing unnecessary
 452    ivs from the set always.  */
 453
 454 DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND,
 455          "iv-always-prune-cand-set-bound",
 456          "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization",
 457          10, 0, 0)
 458
 459 DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE,
 460          "scev-max-expr-size",
 461          "Bound on size of expressions used in the scalar evolutions analyzer",
 462          20, 0, 0)
 463
 464 DEFPARAM(PARAM_OMEGA_MAX_VARS,
 465          "omega-max-vars",
 466          "Bound on the number of variables in Omega constraint systems",
 467          128, 0, 0)
 468
 469 DEFPARAM(PARAM_OMEGA_MAX_GEQS,
 470          "omega-max-geqs",
 471          "Bound on the number of inequalities in Omega constraint systems",
 472          256, 0, 0)
 473
 474 DEFPARAM(PARAM_OMEGA_MAX_EQS,
 475          "omega-max-eqs",
 476          "Bound on the number of equalities in Omega constraint systems",
 477          128, 0, 0)
 478
 479 DEFPARAM(PARAM_OMEGA_MAX_WILD_CARDS,
 480          "omega-max-wild-cards",
 481          "Bound on the number of wild cards in Omega constraint systems",
 482          18, 0, 0)
 483
 484 DEFPARAM(PARAM_OMEGA_HASH_TABLE_SIZE,
 485          "omega-hash-table-size",
 486          "Bound on the size of the hash table in Omega constraint systems",
 487          550, 0, 0)
 488
 489 DEFPARAM(PARAM_OMEGA_MAX_KEYS,
 490          "omega-max-keys",
 491          "Bound on the number of keys in Omega constraint systems",
 492          500, 0, 0)
 493
 494 DEFPARAM(PARAM_OMEGA_ELIMINATE_REDUNDANT_CONSTRAINTS,
 495          "omega-eliminate-redundant-constraints",
 496          "When set to 1, use expensive methods to eliminate all redundant constraints",
 497          0, 0, 1)
 498
 499 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIGNMENT_CHECKS,
 500          "vect-max-version-for-alignment-checks",
 501          "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alignment check",
 502          6, 0, 0)
 503
 504 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS,
 505          "vect-max-version-for-alias-checks",
 506          "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alias check",
 507          10, 0, 0)
 508
 509 DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS,
 510          "max-cselib-memory-locations",
 511          "The maximum memory locations recorded by cselib",
 512          500, 0, 0)
 513
 514 #ifdef ENABLE_GC_ALWAYS_COLLECT
 515 # define GGC_MIN_EXPAND_DEFAULT 0
 516 # define GGC_MIN_HEAPSIZE_DEFAULT 0
 517 #else
 518 # define GGC_MIN_EXPAND_DEFAULT 30
 519 # define GGC_MIN_HEAPSIZE_DEFAULT 4096
 520 #endif
 521
 522 DEFPARAM(GGC_MIN_EXPAND,
 523          "ggc-min-expand",
 524          "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap",
 525          GGC_MIN_EXPAND_DEFAULT, 0, 0)
 526
 527 DEFPARAM(GGC_MIN_HEAPSIZE,
 528          "ggc-min-heapsize",
 529          "Minimum heap size before we start collecting garbage, in kilobytes",
 530          GGC_MIN_HEAPSIZE_DEFAULT, 0, 0)
 531
 532 #undef GGC_MIN_EXPAND_DEFAULT
 533 #undef GGC_MIN_HEAPSIZE_DEFAULT
 534
 535 DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
 536          "max-reload-search-insns",
 537          "The maximum number of instructions to search backward when looking for equivalent reload",
 538          100, 0, 0)
 539
 540 DEFPARAM(PARAM_MAX_ALIASED_VOPS,
 541          "max-aliased-vops",
 542          "The maximum number of virtual operators that a function is allowed to have before triggering memory partitioning heuristics",
 543          100, 0, 0)
 544
 545 DEFPARAM(PARAM_AVG_ALIASED_VOPS,
 546          "avg-aliased-vops",
 547          "The average number of virtual operators that memory statements are allowed to have before triggering memory partitioning heuristics",
 548          1, 0, 0)
 549
 550 DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS,
 551          "max-sched-region-blocks",
 552          "The maximum number of blocks in a region to be considered for interblock scheduling",
 553          10, 0, 0)
 554
 555 DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS,
 556          "max-sched-region-insns",
 557          "The maximum number of insns in a region to be considered for interblock scheduling",
 558          100, 0, 0)
 559
 560 DEFPARAM(PARAM_MAX_PIPELINE_REGION_BLOCKS,
 561          "max-pipeline-region-blocks",
 562          "The maximum number of blocks in a region to be considered for interblock scheduling",
 563          15, 0, 0)
 564
 565 DEFPARAM(PARAM_MAX_PIPELINE_REGION_INSNS,
 566          "max-pipeline-region-insns",
 567          "The maximum number of insns in a region to be considered for interblock scheduling",
 568          200, 0, 0)
 569
 570 DEFPARAM(PARAM_MIN_SPEC_PROB,
 571          "min-spec-prob",
 572          "The minimum probability of reaching a source block for interblock speculative scheduling",
 573          40, 0, 0)
 574
 575 DEFPARAM(PARAM_MAX_SCHED_EXTEND_REGIONS_ITERS,
 576          "max-sched-extend-regions-iters",
 577          "The maximum number of iterations through CFG to extend regions",
 578          0, 0, 0)
 579
 580 DEFPARAM(PARAM_MAX_SCHED_INSN_CONFLICT_DELAY,
 581          "max-sched-insn-conflict-delay",
 582          "The maximum conflict delay for an insn to be considered for speculative motion",
 583          3, 1, 10)
 584
 585 DEFPARAM(PARAM_SCHED_SPEC_PROB_CUTOFF,
 586          "sched-spec-prob-cutoff",
 587          "The minimal probability of speculation success (in percents), so that speculative insn will be scheduled.",
 588          40, 0, 100)
 589
 590 DEFPARAM(PARAM_SELSCHED_MAX_LOOKAHEAD,
 591          "selsched-max-lookahead",
 592          "The maximum size of the lookahead window of selective scheduling",
 593          50, 0, 0)
 594
 595 DEFPARAM(PARAM_SELSCHED_MAX_SCHED_TIMES,
 596          "selsched-max-sched-times",
 597          "Maximum number of times that an insn could be scheduled",
 598          2, 0, 0)
 599
 600 DEFPARAM(PARAM_SELSCHED_INSNS_TO_RENAME,
 601          "selsched-insns-to-rename",
 602          "Maximum number of instructions in the ready list that are considered eligible for renaming",
 603          2, 0, 0)
 604
 605 DEFPARAM (PARAM_SCHED_MEM_TRUE_DEP_COST,
 606           "sched-mem-true-dep-cost",
 607           "Minimal distance between possibly conflicting store and load",
 608           1, 0, 0)
 609
 610 DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
 611          "max-last-value-rtl",
 612          "The maximum number of RTL nodes that can be recorded as combiner's last value",
 613          10000, 0, 0)
 614
 615 /* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
 616    {signed,unsigned} integral types.  This determines N.
 617    Experimentation shows 256 to be a good value.  */
 618 DEFPARAM (PARAM_INTEGER_SHARE_LIMIT,
 619           "integer-share-limit",
 620           "The upper bound for sharing integer constants",
 621           256, 2, 2)
 622
 623 /* Incremental SSA updates for virtual operands may be very slow if
 624    there is a large number of mappings to process.  In those cases, it
 625    is faster to rewrite the virtual symbols from scratch as if they
 626    had been recently introduced.  This heuristic cannot be applied to
 627    SSA mappings for real SSA names, only symbols kept in FUD chains.
 628
 629    PARAM_MIN_VIRTUAL_MAPPINGS specifies the minimum number of virtual
 630    mappings that should be registered to trigger the heuristic.
 631
 632    PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO specifies the ratio between
 633    mappings and symbols.  If the number of virtual mappings is
 634    PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO bigger than the number of
 635    virtual symbols to be updated, then the updater switches to a full
 636    update for those symbols.  */
 637 DEFPARAM (PARAM_MIN_VIRTUAL_MAPPINGS,
 638           "min-virtual-mappings",
 639           "Minimum number of virtual mappings to consider switching to full virtual renames",
 640           100, 0, 0)
 641
 642 DEFPARAM (PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO,
 643           "virtual-mappings-ratio",
 644           "Ratio between virtual mappings and virtual symbols to do full virtual renames",
 645           3, 0, 0)
 646
 647 DEFPARAM (PARAM_SSP_BUFFER_SIZE,
 648           "ssp-buffer-size",
 649           "The lower bound for a buffer to be considered for stack smashing protection",
 650           8, 1, 0)
 651
 652 /* When we thread through a block we have to make copies of the
 653    statements within the block.  Clearly for large blocks the code
 654    duplication is bad.
 655
 656    PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number
 657    of statements and PHI nodes allowed in a block which is going to
 658    be duplicated for thread jumping purposes.
 659
 660    Some simple analysis showed that more than 99% of the jump
 661    threading opportunities are for blocks with less than 15
 662    statements.  So we can get the benefits of jump threading
 663    without excessive code bloat for pathological cases with the
 664    throttle set at 15 statements.  */
 665 DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS,
 666           "max-jump-thread-duplication-stmts",
 667           "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps",
 668           15, 0, 0)
 669
 670 /* This is the maximum number of fields a variable may have before the pointer analysis machinery
 671    will stop trying to treat it in a field-sensitive manner.
 672    There are programs out there with thousands of fields per structure, and handling them
 673    field-sensitively is not worth the cost.  */
 674 DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE,
 675           "max-fields-for-field-sensitive",
 676           "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable",
 677           0, 0, 0)
 678
 679 DEFPARAM(PARAM_MAX_SCHED_READY_INSNS,
 680          "max-sched-ready-insns",
 681          "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass",
 682          100, 0, 0)
 683
 684 /* Prefetching and cache-optimizations related parameters.  Default values are
 685    usually set by machine description.  */
 686
 687 /* The number of insns executed before prefetch is completed.  */
 688
 689 DEFPARAM (PARAM_PREFETCH_LATENCY,
 690          "prefetch-latency",
 691          "The number of insns executed before prefetch is completed",
 692          200, 0, 0)
 693
 694 /* The number of prefetches that can run at the same time.  */
 695
 696 DEFPARAM (PARAM_SIMULTANEOUS_PREFETCHES,
 697           "simultaneous-prefetches",
 698           "The number of prefetches that can run at the same time",
 699           3, 0, 0)
 700
 701 /* The size of L1 cache in kB.  */
 702
 703 DEFPARAM (PARAM_L1_CACHE_SIZE,
 704           "l1-cache-size",
 705           "The size of L1 cache",
 706           64, 0, 0)
 707
 708 /* The size of L1 cache line in bytes.  */
 709
 710 DEFPARAM (PARAM_L1_CACHE_LINE_SIZE,
 711           "l1-cache-line-size",
 712           "The size of L1 cache line",
 713           32, 0, 0)
 714
 715 /* The size of L2 cache in kB.  */
 716
 717 DEFPARAM (PARAM_L2_CACHE_SIZE,
 718           "l2-cache-size",
 719           "The size of L2 cache",
 720           512, 0, 0)
 721
 722 /* Whether we should use canonical types rather than deep "structural"
 723    type checking.  Setting this value to 1 (the default) improves
 724    compilation performance in the C++ and Objective-C++ front end;
 725    this value should only be set to zero to work around bugs in the
 726    canonical type system by disabling it.  */
 727
 728 DEFPARAM (PARAM_USE_CANONICAL_TYPES,
 729           "use-canonical-types",
 730           "Whether to use canonical types",
 731           1, 0, 1)
 732
 733 DEFPARAM (PARAM_MAX_PARTIAL_ANTIC_LENGTH,
 734           "max-partial-antic-length",
 735           "Maximum length of partial antic set when performing tree pre optimization",
 736           100, 0, 0)
 737
 738 /* The following is used as a stop-gap limit for cases where really huge
 739    SCCs blow up memory and compile-time use too much.  If we hit this limit,
 740    SCCVN and such FRE and PRE will be not done at all for the current
 741    function.  */
 742
 743 DEFPARAM (PARAM_SCCVN_MAX_SCC_SIZE,
 744           "sccvn-max-scc-size",
 745           "Maximum size of a SCC before SCCVN stops processing a function",
 746           10000, 10, 0)
 747
 748 DEFPARAM (PARAM_IRA_MAX_LOOPS_NUM,
 749           "ira-max-loops-num",
 750           "max loops number for regional RA",
 751           100, 0, 0)
 752
 753 DEFPARAM (PARAM_IRA_MAX_CONFLICT_TABLE_SIZE,
 754           "ira-max-conflict-table-size",
 755           "max size of conflict table in MB",
 756           1000, 0, 0)
 757
 758 /* Switch initialization conversion will refuse to create arrays that are
 759    bigger than this parameter times the number of switch branches.  */
 760
 761 DEFPARAM (PARAM_SWITCH_CONVERSION_BRANCH_RATIO,
 762           "switch-conversion-max-branch-ratio",
 763           "The maximum ratio between array size and switch branches for "
 764           "a switch conversion to take place",
 765           8, 1, 0)
 766
 767 /*
 768 Local variables:
 769 mode:c
 770 End:
 771 */