gcc/params.def

   1 /* params.def - Run-time parameters.
   2    Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
   3    2011
   4    Free Software Foundation, Inc.
   5    Written by Mark Mitchell <mark@codesourcery.com>.
   6
   7 This file is part of GCC.
   8
   9 GCC is free software; you can redistribute it and/or modify it under
  10 the terms of the GNU General Public License as published by the Free
  11 Software Foundation; either version 3, or (at your option) any later
  12 version.
  13
  14 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  15 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  16 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  17 for more details.
  18
  19 You should have received a copy of the GNU General Public License
  20 along with GCC; see the file COPYING3.  If not see
  21 <http://www.gnu.org/licenses/>.  */
  22
  23 /* This file contains definitions for language-independent
  24    parameters.  The DEFPARAM macro takes 6 arguments:
  25
  26      - The enumeral corresponding to this parameter.
  27
  28      - The name that can be used to set this parameter using the
  29        command-line option `--param <name>=<value>'.
  30
  31      - A help string explaining how the parameter is used.
  32
  33      - A default value for the parameter.
  34
  35      - The minimum acceptable value for the parameter.
  36
  37      - The maximum acceptable value for the parameter (if greater than
  38      the minimum).
  39
  40    Be sure to add an entry to invoke.texi summarizing the parameter.  */
  41
  42 /* The threshold ratio between current and hottest structure counts.
  43    We say that if the ratio of the current structure count,
  44    calculated by profiling, to the hottest structure count
  45    in the program is less than this parameter, then structure
  46    reorganization is not applied. The default is 10%.  */
  47 DEFPARAM (PARAM_STRUCT_REORG_COLD_STRUCT_RATIO,
  48           "struct-reorg-cold-struct-ratio",
  49           "The threshold ratio between current and hottest structure counts",
  50           10, 0, 100)
  51
  52 /* When branch is predicted to be taken with probability lower than this
  53    threshold (in percent), then it is considered well predictable. */
  54 DEFPARAM (PARAM_PREDICTABLE_BRANCH_OUTCOME,
  55           "predictable-branch-outcome",
  56           "Maximal estimated outcome of branch considered predictable",
  57           2, 0, 50)
  58
  59 /* The single function inlining limit. This is the maximum size
  60    of a function counted in internal gcc instructions (not in
  61    real machine instructions) that is eligible for inlining
  62    by the tree inliner.
  63    The default value is 450.
  64    Only functions marked inline (or methods defined in the class
  65    definition for C++) are affected by this.
  66    There are more restrictions to inlining: If inlined functions
  67    call other functions, the already inlined instructions are
  68    counted and once the recursive inline limit (see
  69    "max-inline-insns" parameter) is exceeded, the acceptable size
  70    gets decreased.  */
  71 DEFPARAM (PARAM_MAX_INLINE_INSNS_SINGLE,
  72           "max-inline-insns-single",
  73           "The maximum number of instructions in a single function eligible for inlining",
  74           400, 0, 0)
  75
  76 /* The single function inlining limit for functions that are
  77    inlined by virtue of -finline-functions (-O3).
  78    This limit should be chosen to be below or equal to the limit
  79    that is applied to functions marked inlined (or defined in the
  80    class declaration in C++) given by the "max-inline-insns-single"
  81    parameter.
  82    The default value is 40.  */
  83 DEFPARAM (PARAM_MAX_INLINE_INSNS_AUTO,
  84           "max-inline-insns-auto",
  85           "The maximum number of instructions when automatically inlining",
  86           40, 0, 0)
  87
  88 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE,
  89           "max-inline-insns-recursive",
  90           "The maximum number of instructions inline function can grow to via recursive inlining",
  91           450, 0, 0)
  92
  93 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO,
  94           "max-inline-insns-recursive-auto",
  95           "The maximum number of instructions non-inline function can grow to via recursive inlining",
  96           450, 0, 0)
  97
  98 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH,
  99           "max-inline-recursive-depth",
 100           "The maximum depth of recursive inlining for inline functions",
 101           8, 0, 0)
 102
 103 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO,
 104           "max-inline-recursive-depth-auto",
 105           "The maximum depth of recursive inlining for non-inline functions",
 106           8, 0, 0)
 107
 108 DEFPARAM (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY,
 109           "min-inline-recursive-probability",
 110           "Inline recursively only when the probability of call being executed exceeds the parameter",
 111           10, 0, 0)
 112
 113 /* Limit of iterations of early inliner.  This basically bounds number of
 114    nested indirect calls early inliner can resolve.  Deeper chains are still
 115    handled by late inlining.  */
 116 DEFPARAM (PARAM_EARLY_INLINER_MAX_ITERATIONS,
 117           "max-early-inliner-iterations",
 118           "The maximum number of nested indirect inlining performed by early inliner",
 119           10, 0, 0)
 120
 121 /* Limit on probability of entry BB.  */
 122 DEFPARAM (PARAM_COMDAT_SHARING_PROBABILITY,
 123           "comdat-sharing-probability",
 124           "Probability that COMDAT function will be shared with different compilatoin unit",
 125           20, 0, 0)
 126
 127 /* Limit on probability of entry BB.  */
 128 DEFPARAM (PARAM_PARTIAL_INLINING_ENTRY_PROBABILITY,
 129           "partial-inlining-entry-probability",
 130           "Maximum probability of the entry BB of split region (in percent relative to entry BB of the function) to make partial inlining happen",
 131           70, 0, 0)
 132
 133 /* Limit the number of expansions created by the variable expansion
 134    optimization to avoid register pressure.  */
 135 DEFPARAM (PARAM_MAX_VARIABLE_EXPANSIONS,
 136           "max-variable-expansions-in-unroller",
 137           "If -fvariable-expansion-in-unroller is used, the maximum number of times that an individual variable will be expanded during loop unrolling",
 138           1, 0, 0)
 139
 140 /* Limit loop autovectorization to loops with large enough iteration count.  */
 141 DEFPARAM (PARAM_MIN_VECT_LOOP_BOUND,
 142           "min-vect-loop-bound",
 143           "If -ftree-vectorize is used, the minimal loop bound of a loop to be considered for vectorization",
 144           1, 1, 0)
 145
 146 /* The maximum number of instructions to consider when looking for an
 147    instruction to fill a delay slot.  If more than this arbitrary
 148    number of instructions is searched, the time savings from filling
 149    the delay slot will be minimal so stop searching.  Increasing
 150    values mean more aggressive optimization, making the compile time
 151    increase with probably small improvement in executable run time.  */
 152 DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH,
 153           "max-delay-slot-insn-search",
 154           "The maximum number of instructions to consider to fill a delay slot",
 155           100, 0, 0)
 156
 157 /* When trying to fill delay slots, the maximum number of instructions
 158    to consider when searching for a block with valid live register
 159    information.  Increasing this arbitrarily chosen value means more
 160    aggressive optimization, increasing the compile time.  This
 161    parameter should be removed when the delay slot code is rewritten
 162    to maintain the control-flow graph.  */
 163 DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH,
 164          "max-delay-slot-live-search",
 165          "The maximum number of instructions to consider to find accurate live register information",
 166          333, 0, 0)
 167
 168 /* This parameter limits the number of branch elements that the
 169    scheduler will track anti-dependencies through without resetting
 170    the tracking mechanism.  Large functions with few calls or barriers
 171    can generate lists containing many 1000's of dependencies.  Generally
 172    the compiler either uses all available memory, or runs for far too long.  */
 173 DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH,
 174          "max-pending-list-length",
 175          "The maximum length of scheduling's pending operations list",
 176          32, 0, 0)
 177
 178 DEFPARAM(PARAM_LARGE_FUNCTION_INSNS,
 179          "large-function-insns",
 180          "The size of function body to be considered large",
 181          2700, 0, 0)
 182 DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH,
 183          "large-function-growth",
 184          "Maximal growth due to inlining of large function (in percent)",
 185          100, 0, 0)
 186 DEFPARAM(PARAM_LARGE_UNIT_INSNS,
 187          "large-unit-insns",
 188          "The size of translation unit to be considered large",
 189          10000, 0, 0)
 190 DEFPARAM(PARAM_INLINE_UNIT_GROWTH,
 191          "inline-unit-growth",
 192          "How much can given compilation unit grow because of the inlining (in percent)",
 193          30, 0, 0)
 194 DEFPARAM(PARAM_IPCP_UNIT_GROWTH,
 195          "ipcp-unit-growth",
 196          "How much can given compilation unit grow because of the interprocedural constant propagation (in percent)",
 197          10, 0, 0)
 198 DEFPARAM(PARAM_EARLY_INLINING_INSNS,
 199          "early-inlining-insns",
 200          "Maximal estimated growth of function body caused by early inlining of single call",
 201          10, 0, 0)
 202 DEFPARAM(PARAM_LARGE_STACK_FRAME,
 203          "large-stack-frame",
 204          "The size of stack frame to be considered large",
 205          256, 0, 0)
 206 DEFPARAM(PARAM_STACK_FRAME_GROWTH,
 207          "large-stack-frame-growth",
 208          "Maximal stack frame growth due to inlining (in percent)",
 209          1000, 0, 0)
 210
 211 /* The GCSE optimization will be disabled if it would require
 212    significantly more memory than this value.  */
 213 DEFPARAM(PARAM_MAX_GCSE_MEMORY,
 214          "max-gcse-memory",
 215          "The maximum amount of memory to be allocated by GCSE",
 216          50 * 1024 * 1024, 0, 0)
 217
 218 /* The GCSE optimization of an expression will avoided if the ratio of
 219    insertions to deletions is greater than this value.  */
 220 DEFPARAM(PARAM_MAX_GCSE_INSERTION_RATIO,
 221          "max-gcse-insertion-ratio",
 222          "The maximum ratio of insertions to deletions of expressions in GCSE",
 223          20, 0, 0)
 224
 225 /* This is the threshold ratio when to perform partial redundancy
 226    elimination after reload. We perform partial redundancy elimination
 227    when the following holds:
 228    (Redundant load execution count)
 229    ------------------------------- >= GCSE_AFTER_RELOAD_PARTIAL_FRACTION
 230    (Added loads execution count)                                          */
 231 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_PARTIAL_FRACTION,
 232         "gcse-after-reload-partial-fraction",
 233         "The threshold ratio for performing partial redundancy elimination after reload",
 234         3, 0, 0)
 235 /* This is the threshold ratio of the critical edges execution count compared to
 236    the redundant loads execution count that permits performing the load
 237    redundancy elimination in gcse after reload.  */
 238 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_CRITICAL_FRACTION,
 239         "gcse-after-reload-critical-fraction",
 240         "The threshold ratio of critical edges execution count that permit performing redundancy elimination after reload",
 241         10, 0, 0)
 242
 243 /* GCSE will use GCSE_COST_DISTANCE_RATION as a scaling factor
 244    to calculate maximum distance for which an expression is allowed to move
 245    from its rtx_cost.  */
 246 DEFPARAM(PARAM_GCSE_COST_DISTANCE_RATIO,
 247          "gcse-cost-distance-ratio",
 248          "Scaling factor in calculation of maximum distance an expression can be moved by GCSE optimizations",
 249          10, 0, 0)
 250 /* GCSE won't restrict distance for which an expression with rtx_cost greater
 251    than COSTS_N_INSN(GCSE_UNRESTRICTED_COST) is allowed to move.  */
 252 DEFPARAM(PARAM_GCSE_UNRESTRICTED_COST,
 253          "gcse-unrestricted-cost",
 254          "Cost at which GCSE optimizations will not constraint the distance an expression can travel",
 255          3, 0, 0)
 256
 257 /* How deep from a given basic block the dominator tree should be searched
 258    for expressions to hoist to the block.  The value of 0 will avoid limiting
 259    the search.  */
 260 DEFPARAM(PARAM_MAX_HOIST_DEPTH,
 261          "max-hoist-depth",
 262          "Maximum depth of search in the dominator tree for expressions to hoist",
 263          30, 0, 0)
 264
 265 /* This parameter limits the number of insns in a loop that will be unrolled,
 266    and by how much the loop is unrolled.
 267
 268    This limit should be at most half of the peeling limits:  loop unroller
 269    decides to not unroll loops that iterate fewer than 2*number of allowed
 270    unrollings and thus we would have loops that are neither peeled or unrolled
 271    otherwise.  */
 272 DEFPARAM(PARAM_MAX_UNROLLED_INSNS,
 273          "max-unrolled-insns",
 274          "The maximum number of instructions to consider to unroll in a loop",
 275          200, 0, 0)
 276 /* This parameter limits how many times the loop is unrolled depending
 277    on number of insns really executed in each iteration.  */
 278 DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS,
 279          "max-average-unrolled-insns",
 280          "The maximum number of instructions to consider to unroll in a loop on average",
 281          80, 0, 0)
 282 /* The maximum number of unrollings of a single loop.  */
 283 DEFPARAM(PARAM_MAX_UNROLL_TIMES,
 284         "max-unroll-times",
 285         "The maximum number of unrollings of a single loop",
 286         8, 0, 0)
 287 /* The maximum number of insns of a peeled loop.  */
 288 DEFPARAM(PARAM_MAX_PEELED_INSNS,
 289         "max-peeled-insns",
 290         "The maximum number of insns of a peeled loop",
 291         400, 0, 0)
 292 /* The maximum number of peelings of a single loop.  */
 293 DEFPARAM(PARAM_MAX_PEEL_TIMES,
 294         "max-peel-times",
 295         "The maximum number of peelings of a single loop",
 296         16, 0, 0)
 297 /* The maximum number of insns of a peeled loop.  */
 298 DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS,
 299         "max-completely-peeled-insns",
 300         "The maximum number of insns of a completely peeled loop",
 301         400, 0, 0)
 302 /* The maximum number of peelings of a single loop that is peeled completely.  */
 303 DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES,
 304         "max-completely-peel-times",
 305         "The maximum number of peelings of a single loop that is peeled completely",
 306         16, 0, 0)
 307 /* The maximum number of insns of a peeled loop that rolls only once.  */
 308 DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS,
 309         "max-once-peeled-insns",
 310         "The maximum number of insns of a peeled loop that rolls only once",
 311         400, 0, 0)
 312 /* The maximum depth of a loop nest we completely peel.  */
 313 DEFPARAM(PARAM_MAX_UNROLL_ITERATIONS,
 314          "max-completely-peel-loop-nest-depth",
 315          "The maximum depth of a loop nest we completely peel",
 316          8, 0, 0)
 317
 318 /* The maximum number of insns of an unswitched loop.  */
 319 DEFPARAM(PARAM_MAX_UNSWITCH_INSNS,
 320         "max-unswitch-insns",
 321         "The maximum number of insns of an unswitched loop",
 322         50, 0, 0)
 323 /* The maximum level of recursion in unswitch_single_loop.  */
 324 DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL,
 325         "max-unswitch-level",
 326         "The maximum number of unswitchings in a single loop",
 327         3, 0, 0)
 328
 329 /* The maximum number of iterations of a loop the brute force algorithm
 330    for analysis of # of iterations of the loop tries to evaluate.  */
 331 DEFPARAM(PARAM_MAX_ITERATIONS_TO_TRACK,
 332         "max-iterations-to-track",
 333         "Bound on the number of iterations the brute force # of iterations analysis algorithm evaluates",
 334         1000, 0, 0)
 335 /* A cutoff to avoid costly computations of the number of iterations in
 336    the doloop transformation.  */
 337 DEFPARAM(PARAM_MAX_ITERATIONS_COMPUTATION_COST,
 338         "max-iterations-computation-cost",
 339         "Bound on the cost of an expression to compute the number of iterations",
 340         10, 0, 0)
 341
 342 /* This parameter is used to tune SMS MAX II calculations.  */
 343 DEFPARAM(PARAM_SMS_MAX_II_FACTOR,
 344          "sms-max-ii-factor",
 345          "A factor for tuning the upper bound that swing modulo scheduler uses for scheduling a loop",
 346          100, 0, 0)
 347 DEFPARAM(PARAM_SMS_DFA_HISTORY,
 348          "sms-dfa-history",
 349          "The number of cycles the swing modulo scheduler considers when checking conflicts using DFA",
 350          0, 0, 0)
 351 DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD,
 352          "sms-loop-average-count-threshold",
 353          "A threshold on the average loop count considered by the swing modulo scheduler",
 354          0, 0, 0)
 355
 356 DEFPARAM(HOT_BB_COUNT_FRACTION,
 357          "hot-bb-count-fraction",
 358          "Select fraction of the maximal count of repetitions of basic block in program given basic block needs to have to be considered hot",
 359          10000, 0, 0)
 360 DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
 361          "hot-bb-frequency-fraction",
 362          "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot",
 363          1000, 0, 0)
 364
 365 DEFPARAM (PARAM_ALIGN_THRESHOLD,
 366           "align-threshold",
 367           "Select fraction of the maximal frequency of executions of basic block in function given basic block get alignment",
 368           100, 0, 0)
 369
 370 DEFPARAM (PARAM_ALIGN_LOOP_ITERATIONS,
 371           "align-loop-iterations",
 372           "Loops iterating at least selected number of iterations will get loop alignement.",
 373           4, 0, 0)
 374
 375 /* For guessed profiles, the loops having unknown number of iterations
 376    are predicted to iterate relatively few (10) times at average.
 377    For functions containing one loop with large known number of iterations
 378    and other loops having unbounded loops we would end up predicting all
 379    the other loops cold that is not usually the case.  So we need to artificially
 380    flatten the profile.
 381
 382    We need to cut the maximal predicted iterations to large enough iterations
 383    so the loop appears important, but safely within HOT_BB_COUNT_FRACTION
 384    range.  */
 385
 386 DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS,
 387          "max-predicted-iterations",
 388          "The maximum number of loop iterations we predict statically",
 389          100, 0, 0)
 390 DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
 391          "tracer-dynamic-coverage-feedback",
 392          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available",
 393          95, 0, 100)
 394 DEFPARAM(TRACER_DYNAMIC_COVERAGE,
 395          "tracer-dynamic-coverage",
 396          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available",
 397          75, 0, 100)
 398 DEFPARAM(TRACER_MAX_CODE_GROWTH,
 399          "tracer-max-code-growth",
 400          "Maximal code growth caused by tail duplication (in percent)",
 401          100, 0, 0)
 402 DEFPARAM(TRACER_MIN_BRANCH_RATIO,
 403          "tracer-min-branch-ratio",
 404          "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent)",
 405          10, 0, 100)
 406 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
 407          "tracer-min-branch-probability-feedback",
 408          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available",
 409          80, 0, 100)
 410 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
 411          "tracer-min-branch-probability",
 412          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available",
 413          50, 0, 100)
 414
 415 /* The maximum number of incoming edges to consider for crossjumping.  */
 416 DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
 417          "max-crossjump-edges",
 418          "The maximum number of incoming edges to consider for crossjumping",
 419          100, 0, 0)
 420
 421 /* The minimum number of matching instructions to consider for crossjumping.  */
 422 DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS,
 423      "min-crossjump-insns",
 424      "The minimum number of matching instructions to consider for crossjumping",
 425      5, 0, 0)
 426
 427 /* The maximum number expansion factor when copying basic blocks.  */
 428 DEFPARAM(PARAM_MAX_GROW_COPY_BB_INSNS,
 429      "max-grow-copy-bb-insns",
 430      "The maximum expansion factor when copying basic blocks",
 431      8, 0, 0)
 432
 433 /* The maximum number of insns to duplicate when unfactoring computed gotos.  */
 434 DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS,
 435      "max-goto-duplication-insns",
 436      "The maximum number of insns to duplicate when unfactoring computed gotos",
 437      8, 0, 0)
 438
 439 /* The maximum length of path considered in cse.  */
 440 DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
 441          "max-cse-path-length",
 442          "The maximum length of path considered in cse",
 443          10, 0, 0)
 444 DEFPARAM(PARAM_MAX_CSE_INSNS,
 445          "max-cse-insns",
 446          "The maximum instructions CSE process before flushing",
 447          1000, 0, 0)
 448
 449 /* The cost of expression in loop invariant motion that is considered
 450    expensive.  */
 451 DEFPARAM(PARAM_LIM_EXPENSIVE,
 452          "lim-expensive",
 453          "The minimum cost of an expensive expression in the loop invariant motion",
 454          20, 0, 0)
 455
 456 /* Bound on number of candidates for induction variables below that
 457    all candidates are considered for each use in induction variable
 458    optimizations.  */
 459
 460 DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND,
 461          "iv-consider-all-candidates-bound",
 462          "Bound on number of candidates below that all candidates are considered in iv optimizations",
 463          30, 0, 0)
 464
 465 /* The induction variable optimizations give up on loops that contain more
 466    induction variable uses.  */
 467
 468 DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES,
 469          "iv-max-considered-uses",
 470          "Bound on number of iv uses in loop optimized in iv optimizations",
 471          250, 0, 0)
 472
 473 /* If there are at most this number of ivs in the set, try removing unnecessary
 474    ivs from the set always.  */
 475
 476 DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND,
 477          "iv-always-prune-cand-set-bound",
 478          "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization",
 479          10, 0, 0)
 480
 481 DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE,
 482          "scev-max-expr-size",
 483          "Bound on size of expressions used in the scalar evolutions analyzer",
 484          100, 0, 0)
 485
 486 DEFPARAM(PARAM_SCEV_MAX_EXPR_COMPLEXITY,
 487          "scev-max-expr-complexity",
 488          "Bound on the complexity of the expressions in the scalar evolutions analyzer",
 489          10, 0, 0)
 490
 491 DEFPARAM(PARAM_OMEGA_MAX_VARS,
 492          "omega-max-vars",
 493          "Bound on the number of variables in Omega constraint systems",
 494          128, 0, 0)
 495
 496 DEFPARAM(PARAM_OMEGA_MAX_GEQS,
 497          "omega-max-geqs",
 498          "Bound on the number of inequalities in Omega constraint systems",
 499          256, 0, 0)
 500
 501 DEFPARAM(PARAM_OMEGA_MAX_EQS,
 502          "omega-max-eqs",
 503          "Bound on the number of equalities in Omega constraint systems",
 504          128, 0, 0)
 505
 506 DEFPARAM(PARAM_OMEGA_MAX_WILD_CARDS,
 507          "omega-max-wild-cards",
 508          "Bound on the number of wild cards in Omega constraint systems",
 509          18, 0, 0)
 510
 511 DEFPARAM(PARAM_OMEGA_HASH_TABLE_SIZE,
 512          "omega-hash-table-size",
 513          "Bound on the size of the hash table in Omega constraint systems",
 514          550, 0, 0)
 515
 516 DEFPARAM(PARAM_OMEGA_MAX_KEYS,
 517          "omega-max-keys",
 518          "Bound on the number of keys in Omega constraint systems",
 519          500, 0, 0)
 520
 521 DEFPARAM(PARAM_OMEGA_ELIMINATE_REDUNDANT_CONSTRAINTS,
 522          "omega-eliminate-redundant-constraints",
 523          "When set to 1, use expensive methods to eliminate all redundant constraints",
 524          0, 0, 1)
 525
 526 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIGNMENT_CHECKS,
 527          "vect-max-version-for-alignment-checks",
 528          "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alignment check",
 529          6, 0, 0)
 530
 531 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS,
 532          "vect-max-version-for-alias-checks",
 533          "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alias check",
 534          10, 0, 0)
 535
 536 DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS,
 537          "max-cselib-memory-locations",
 538          "The maximum memory locations recorded by cselib",
 539          500, 0, 0)
 540
 541 #ifdef ENABLE_GC_ALWAYS_COLLECT
 542 # define GGC_MIN_EXPAND_DEFAULT 0
 543 # define GGC_MIN_HEAPSIZE_DEFAULT 0
 544 #else
 545 # define GGC_MIN_EXPAND_DEFAULT 30
 546 # define GGC_MIN_HEAPSIZE_DEFAULT 4096
 547 #endif
 548
 549 DEFPARAM(GGC_MIN_EXPAND,
 550          "ggc-min-expand",
 551          "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap",
 552          GGC_MIN_EXPAND_DEFAULT, 0, 0)
 553
 554 DEFPARAM(GGC_MIN_HEAPSIZE,
 555          "ggc-min-heapsize",
 556          "Minimum heap size before we start collecting garbage, in kilobytes",
 557          GGC_MIN_HEAPSIZE_DEFAULT, 0, 0)
 558
 559 #undef GGC_MIN_EXPAND_DEFAULT
 560 #undef GGC_MIN_HEAPSIZE_DEFAULT
 561
 562 DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
 563          "max-reload-search-insns",
 564          "The maximum number of instructions to search backward when looking for equivalent reload",
 565          100, 0, 0)
 566
 567 DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS,
 568          "max-sched-region-blocks",
 569          "The maximum number of blocks in a region to be considered for interblock scheduling",
 570          10, 0, 0)
 571
 572 DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS,
 573          "max-sched-region-insns",
 574          "The maximum number of insns in a region to be considered for interblock scheduling",
 575          100, 0, 0)
 576
 577 DEFPARAM(PARAM_MAX_PIPELINE_REGION_BLOCKS,
 578          "max-pipeline-region-blocks",
 579          "The maximum number of blocks in a region to be considered for interblock scheduling",
 580          15, 0, 0)
 581
 582 DEFPARAM(PARAM_MAX_PIPELINE_REGION_INSNS,
 583          "max-pipeline-region-insns",
 584          "The maximum number of insns in a region to be considered for interblock scheduling",
 585          200, 0, 0)
 586
 587 DEFPARAM(PARAM_MIN_SPEC_PROB,
 588          "min-spec-prob",
 589          "The minimum probability of reaching a source block for interblock speculative scheduling",
 590          40, 0, 0)
 591
 592 DEFPARAM(PARAM_MAX_SCHED_EXTEND_REGIONS_ITERS,
 593          "max-sched-extend-regions-iters",
 594          "The maximum number of iterations through CFG to extend regions",
 595          0, 0, 0)
 596
 597 DEFPARAM(PARAM_MAX_SCHED_INSN_CONFLICT_DELAY,
 598          "max-sched-insn-conflict-delay",
 599          "The maximum conflict delay for an insn to be considered for speculative motion",
 600          3, 1, 10)
 601
 602 DEFPARAM(PARAM_SCHED_SPEC_PROB_CUTOFF,
 603          "sched-spec-prob-cutoff",
 604          "The minimal probability of speculation success (in percents), so that speculative insn will be scheduled.",
 605          40, 0, 100)
 606
 607 DEFPARAM(PARAM_SELSCHED_MAX_LOOKAHEAD,
 608          "selsched-max-lookahead",
 609          "The maximum size of the lookahead window of selective scheduling",
 610          50, 0, 0)
 611
 612 DEFPARAM(PARAM_SELSCHED_MAX_SCHED_TIMES,
 613          "selsched-max-sched-times",
 614          "Maximum number of times that an insn could be scheduled",
 615          2, 0, 0)
 616
 617 DEFPARAM(PARAM_SELSCHED_INSNS_TO_RENAME,
 618          "selsched-insns-to-rename",
 619          "Maximum number of instructions in the ready list that are considered eligible for renaming",
 620          2, 0, 0)
 621
 622 DEFPARAM (PARAM_SCHED_MEM_TRUE_DEP_COST,
 623           "sched-mem-true-dep-cost",
 624           "Minimal distance between possibly conflicting store and load",
 625           1, 0, 0)
 626
 627 DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
 628          "max-last-value-rtl",
 629          "The maximum number of RTL nodes that can be recorded as combiner's last value",
 630          10000, 0, 0)
 631
 632 /* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
 633    {signed,unsigned} integral types.  This determines N.
 634    Experimentation shows 256 to be a good value.  */
 635 DEFPARAM (PARAM_INTEGER_SHARE_LIMIT,
 636           "integer-share-limit",
 637           "The upper bound for sharing integer constants",
 638           256, 2, 2)
 639
 640 /* Incremental SSA updates for virtual operands may be very slow if
 641    there is a large number of mappings to process.  In those cases, it
 642    is faster to rewrite the virtual symbols from scratch as if they
 643    had been recently introduced.  This heuristic cannot be applied to
 644    SSA mappings for real SSA names, only symbols kept in FUD chains.
 645
 646    PARAM_MIN_VIRTUAL_MAPPINGS specifies the minimum number of virtual
 647    mappings that should be registered to trigger the heuristic.
 648
 649    PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO specifies the ratio between
 650    mappings and symbols.  If the number of virtual mappings is
 651    PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO bigger than the number of
 652    virtual symbols to be updated, then the updater switches to a full
 653    update for those symbols.  */
 654 DEFPARAM (PARAM_MIN_VIRTUAL_MAPPINGS,
 655           "min-virtual-mappings",
 656           "Minimum number of virtual mappings to consider switching to full virtual renames",
 657           100, 0, 0)
 658
 659 DEFPARAM (PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO,
 660           "virtual-mappings-ratio",
 661           "Ratio between virtual mappings and virtual symbols to do full virtual renames",
 662           3, 0, 0)
 663
 664 DEFPARAM (PARAM_SSP_BUFFER_SIZE,
 665           "ssp-buffer-size",
 666           "The lower bound for a buffer to be considered for stack smashing protection",
 667           8, 1, 0)
 668
 669 /* When we thread through a block we have to make copies of the
 670    statements within the block.  Clearly for large blocks the code
 671    duplication is bad.
 672
 673    PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number
 674    of statements and PHI nodes allowed in a block which is going to
 675    be duplicated for thread jumping purposes.
 676
 677    Some simple analysis showed that more than 99% of the jump
 678    threading opportunities are for blocks with less than 15
 679    statements.  So we can get the benefits of jump threading
 680    without excessive code bloat for pathological cases with the
 681    throttle set at 15 statements.  */
 682 DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS,
 683           "max-jump-thread-duplication-stmts",
 684           "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps",
 685           15, 0, 0)
 686
 687 /* This is the maximum number of fields a variable may have before the pointer analysis machinery
 688    will stop trying to treat it in a field-sensitive manner.
 689    There are programs out there with thousands of fields per structure, and handling them
 690    field-sensitively is not worth the cost.  */
 691 DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE,
 692           "max-fields-for-field-sensitive",
 693           "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable",
 694           0, 0, 0)
 695
 696 DEFPARAM(PARAM_MAX_SCHED_READY_INSNS,
 697          "max-sched-ready-insns",
 698          "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass",
 699          100, 0, 0)
 700
 701 /* Prefetching and cache-optimizations related parameters.  Default values are
 702    usually set by machine description.  */
 703
 704 /* The number of insns executed before prefetch is completed.  */
 705
 706 DEFPARAM (PARAM_PREFETCH_LATENCY,
 707          "prefetch-latency",
 708          "The number of insns executed before prefetch is completed",
 709          200, 0, 0)
 710
 711 /* The number of prefetches that can run at the same time.  */
 712
 713 DEFPARAM (PARAM_SIMULTANEOUS_PREFETCHES,
 714           "simultaneous-prefetches",
 715           "The number of prefetches that can run at the same time",
 716           3, 0, 0)
 717
 718 /* The size of L1 cache in kB.  */
 719
 720 DEFPARAM (PARAM_L1_CACHE_SIZE,
 721           "l1-cache-size",
 722           "The size of L1 cache",
 723           64, 0, 0)
 724
 725 /* The size of L1 cache line in bytes.  */
 726
 727 DEFPARAM (PARAM_L1_CACHE_LINE_SIZE,
 728           "l1-cache-line-size",
 729           "The size of L1 cache line",
 730           32, 0, 0)
 731
 732 /* The size of L2 cache in kB.  */
 733
 734 DEFPARAM (PARAM_L2_CACHE_SIZE,
 735           "l2-cache-size",
 736           "The size of L2 cache",
 737           512, 0, 0)
 738
 739 /* Whether we should use canonical types rather than deep "structural"
 740    type checking.  Setting this value to 1 (the default) improves
 741    compilation performance in the C++ and Objective-C++ front end;
 742    this value should only be set to zero to work around bugs in the
 743    canonical type system by disabling it.  */
 744
 745 DEFPARAM (PARAM_USE_CANONICAL_TYPES,
 746           "use-canonical-types",
 747           "Whether to use canonical types",
 748           1, 0, 1)
 749
 750 DEFPARAM (PARAM_MAX_PARTIAL_ANTIC_LENGTH,
 751           "max-partial-antic-length",
 752           "Maximum length of partial antic set when performing tree pre optimization",
 753           100, 0, 0)
 754
 755 /* The following is used as a stop-gap limit for cases where really huge
 756    SCCs blow up memory and compile-time use too much.  If we hit this limit,
 757    SCCVN and such FRE and PRE will be not done at all for the current
 758    function.  */
 759
 760 DEFPARAM (PARAM_SCCVN_MAX_SCC_SIZE,
 761           "sccvn-max-scc-size",
 762           "Maximum size of a SCC before SCCVN stops processing a function",
 763           10000, 10, 0)
 764
 765 DEFPARAM (PARAM_IRA_MAX_LOOPS_NUM,
 766           "ira-max-loops-num",
 767           "Max loops number for regional RA",
 768           100, 0, 0)
 769
 770 DEFPARAM (PARAM_IRA_MAX_CONFLICT_TABLE_SIZE,
 771           "ira-max-conflict-table-size",
 772           "Max size of conflict table in MB",
 773           1000, 0, 0)
 774
 775 DEFPARAM (PARAM_IRA_LOOP_RESERVED_REGS,
 776           "ira-loop-reserved-regs",
 777           "The number of registers in each class kept unused by loop invariant motion",
 778           2, 0, 0)
 779
 780 /* Switch initialization conversion will refuse to create arrays that are
 781    bigger than this parameter times the number of switch branches.  */
 782
 783 DEFPARAM (PARAM_SWITCH_CONVERSION_BRANCH_RATIO,
 784           "switch-conversion-max-branch-ratio",
 785           "The maximum ratio between array size and switch branches for "
 786           "a switch conversion to take place",
 787           8, 1, 0)
 788
 789 /* Size of tiles when doing loop blocking.  */
 790
 791 DEFPARAM (PARAM_LOOP_BLOCK_TILE_SIZE,
 792           "loop-block-tile-size",
 793           "size of tiles for loop blocking",
 794           51, 0, 0)
 795
 796 /* Maximal number of parameters that we allow in a SCoP.  */
 797
 798 DEFPARAM (PARAM_GRAPHITE_MAX_NB_SCOP_PARAMS,
 799           "graphite-max-nb-scop-params",
 800           "maximum number of parameters in a SCoP",
 801           10, 0, 0)
 802
 803 /* Maximal number of basic blocks in the functions analyzed by Graphite.  */
 804
 805 DEFPARAM (PARAM_GRAPHITE_MAX_BBS_PER_FUNCTION,
 806           "graphite-max-bbs-per-function",
 807           "maximum number of basic blocks per function to be analyzed by Graphite",
 808           100, 0, 0)
 809
 810 /* Avoid doing loop invariant motion on very large loops.  */
 811
 812 DEFPARAM (PARAM_LOOP_INVARIANT_MAX_BBS_IN_LOOP,
 813           "loop-invariant-max-bbs-in-loop",
 814           "Max basic blocks number in loop for loop invariant motion",
 815           10000, 0, 0)
 816
 817 /* Avoid SLP vectorization of large basic blocks.  */
 818 DEFPARAM (PARAM_SLP_MAX_INSNS_IN_BB,
 819           "slp-max-insns-in-bb",
 820           "Maximum number of instructions in basic block to be considered for SLP vectorization",
 821           1000, 0, 0)
 822
 823 DEFPARAM (PARAM_MIN_INSN_TO_PREFETCH_RATIO,
 824           "min-insn-to-prefetch-ratio",
 825           "Min. ratio of insns to prefetches to enable prefetching for "
 826           "a loop with an unknown trip count",
 827           10, 0, 0)
 828
 829 DEFPARAM (PARAM_PREFETCH_MIN_INSN_TO_MEM_RATIO,
 830           "prefetch-min-insn-to-mem-ratio",
 831           "Min. ratio of insns to mem ops to enable prefetching in a loop",
 832           3, 0, 0)
 833
 834 /* Set maximum hash table size for var tracking.  */
 835
 836 DEFPARAM (PARAM_MAX_VARTRACK_SIZE,
 837           "max-vartrack-size",
 838           "Max. size of var tracking hash tables",
 839           50000000, 0, 0)
 840
 841 /* Set minimum insn uid for non-debug insns.  */
 842
 843 DEFPARAM (PARAM_MIN_NONDEBUG_INSN_UID,
 844           "min-nondebug-insn-uid",
 845           "The minimum UID to be used for a nondebug insn",
 846           0, 1, 0)
 847
 848 DEFPARAM (PARAM_IPA_SRA_PTR_GROWTH_FACTOR,
 849           "ipa-sra-ptr-growth-factor",
 850           "Maximum allowed growth of size of new parameters ipa-sra replaces "
 851           "a pointer to an aggregate with",
 852           2, 0, 0)
 853
 854 DEFPARAM (PARAM_DEVIRT_TYPE_LIST_SIZE,
 855           "devirt-type-list-size",
 856           "Maximum size of a type list associated with each parameter for "
 857           "devirtualization",
 858           8, 0, 0)
 859
 860 /* WHOPR partitioning configuration.  */
 861
 862 DEFPARAM (PARAM_LTO_PARTITIONS,
 863           "lto-partitions",
 864           "Number of paritions program should be split to",
 865           32, 0, 0)
 866
 867 DEFPARAM (MIN_PARTITION_SIZE,
 868           "lto-min-partition",
 869           "Size of minimal paritition for WHOPR (in estimated instructions)",
 870           1000, 0, 0)
 871
 872 /* Diagnostic parameters.  */
 873
 874 DEFPARAM (CXX_MAX_NAMESPACES_FOR_DIAGNOSTIC_HELP,
 875           "cxx-max-namespaces-for-diagnostic-help",
 876           "Maximum number of namespaces to search for alternatives when "
 877           "name lookup fails",
 878           1000, 0, 0)
 879
 880 /*
 881 Local variables:
 882 mode:c
 883 End:
 884 */