gcc/params.def

   1 /* params.def - Run-time parameters.
   2    Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
   3    2011, 2012
   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 /* When branch is predicted to be taken with probability lower than this
  43    threshold (in percent), then it is considered well predictable. */
  44 DEFPARAM (PARAM_PREDICTABLE_BRANCH_OUTCOME,
  45           "predictable-branch-outcome",
  46           "Maximal estimated outcome of branch considered predictable",
  47           2, 0, 50)
  48
  49 /* The single function inlining limit. This is the maximum size
  50    of a function counted in internal gcc instructions (not in
  51    real machine instructions) that is eligible for inlining
  52    by the tree inliner.
  53    The default value is 450.
  54    Only functions marked inline (or methods defined in the class
  55    definition for C++) are affected by this.
  56    There are more restrictions to inlining: If inlined functions
  57    call other functions, the already inlined instructions are
  58    counted and once the recursive inline limit (see
  59    "max-inline-insns" parameter) is exceeded, the acceptable size
  60    gets decreased.  */
  61 DEFPARAM (PARAM_MAX_INLINE_INSNS_SINGLE,
  62           "max-inline-insns-single",
  63           "The maximum number of instructions in a single function eligible for inlining",
  64           400, 0, 0)
  65
  66 /* The single function inlining limit for functions that are
  67    inlined by virtue of -finline-functions (-O3).
  68    This limit should be chosen to be below or equal to the limit
  69    that is applied to functions marked inlined (or defined in the
  70    class declaration in C++) given by the "max-inline-insns-single"
  71    parameter.
  72    The default value is 40.  */
  73 DEFPARAM (PARAM_MAX_INLINE_INSNS_AUTO,
  74           "max-inline-insns-auto",
  75           "The maximum number of instructions when automatically inlining",
  76           40, 0, 0)
  77
  78 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE,
  79           "max-inline-insns-recursive",
  80           "The maximum number of instructions inline function can grow to via recursive inlining",
  81           450, 0, 0)
  82
  83 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO,
  84           "max-inline-insns-recursive-auto",
  85           "The maximum number of instructions non-inline function can grow to via recursive inlining",
  86           450, 0, 0)
  87
  88 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH,
  89           "max-inline-recursive-depth",
  90           "The maximum depth of recursive inlining for inline functions",
  91           8, 0, 0)
  92
  93 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO,
  94           "max-inline-recursive-depth-auto",
  95           "The maximum depth of recursive inlining for non-inline functions",
  96           8, 0, 0)
  97
  98 DEFPARAM (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY,
  99           "min-inline-recursive-probability",
 100           "Inline recursively only when the probability of call being executed exceeds the parameter",
 101           10, 0, 0)
 102
 103 /* Limit of iterations of early inliner.  This basically bounds number of
 104    nested indirect calls early inliner can resolve.  Deeper chains are still
 105    handled by late inlining.  */
 106 DEFPARAM (PARAM_EARLY_INLINER_MAX_ITERATIONS,
 107           "max-early-inliner-iterations",
 108           "The maximum number of nested indirect inlining performed by early inliner",
 109           10, 0, 0)
 110
 111 /* Limit on probability of entry BB.  */
 112 DEFPARAM (PARAM_COMDAT_SHARING_PROBABILITY,
 113           "comdat-sharing-probability",
 114           "Probability that COMDAT function will be shared with different compilation unit",
 115           20, 0, 0)
 116
 117 /* Limit on probability of entry BB.  */
 118 DEFPARAM (PARAM_PARTIAL_INLINING_ENTRY_PROBABILITY,
 119           "partial-inlining-entry-probability",
 120           "Maximum probability of the entry BB of split region (in percent relative to entry BB of the function) to make partial inlining happen",
 121           70, 0, 0)
 122
 123 /* Limit the number of expansions created by the variable expansion
 124    optimization to avoid register pressure.  */
 125 DEFPARAM (PARAM_MAX_VARIABLE_EXPANSIONS,
 126           "max-variable-expansions-in-unroller",
 127           "If -fvariable-expansion-in-unroller is used, the maximum number of times that an individual variable will be expanded during loop unrolling",
 128           1, 0, 0)
 129
 130 /* Limit loop autovectorization to loops with large enough iteration count.  */
 131 DEFPARAM (PARAM_MIN_VECT_LOOP_BOUND,
 132           "min-vect-loop-bound",
 133           "If -ftree-vectorize is used, the minimal loop bound of a loop to be considered for vectorization",
 134           1, 1, 0)
 135
 136 /* The maximum number of instructions to consider when looking for an
 137    instruction to fill a delay slot.  If more than this arbitrary
 138    number of instructions is searched, the time savings from filling
 139    the delay slot will be minimal so stop searching.  Increasing
 140    values mean more aggressive optimization, making the compile time
 141    increase with probably small improvement in executable run time.  */
 142 DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH,
 143           "max-delay-slot-insn-search",
 144           "The maximum number of instructions to consider to fill a delay slot",
 145           100, 0, 0)
 146
 147 /* When trying to fill delay slots, the maximum number of instructions
 148    to consider when searching for a block with valid live register
 149    information.  Increasing this arbitrarily chosen value means more
 150    aggressive optimization, increasing the compile time.  This
 151    parameter should be removed when the delay slot code is rewritten
 152    to maintain the control-flow graph.  */
 153 DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH,
 154          "max-delay-slot-live-search",
 155          "The maximum number of instructions to consider to find accurate live register information",
 156          333, 0, 0)
 157
 158 /* This parameter limits the number of branch elements that the
 159    scheduler will track anti-dependencies through without resetting
 160    the tracking mechanism.  Large functions with few calls or barriers
 161    can generate lists containing many 1000's of dependencies.  Generally
 162    the compiler either uses all available memory, or runs for far too long.  */
 163 DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH,
 164          "max-pending-list-length",
 165          "The maximum length of scheduling's pending operations list",
 166          32, 0, 0)
 167
 168 /* This parameter limits the number of backtracking attempts when using the
 169    haifa scheduler for modulo scheduling.  */
 170 DEFPARAM(PARAM_MAX_MODULO_BACKTRACK_ATTEMPTS,
 171          "max-modulo-backtrack-attempts",
 172          "The maximum number of backtrack attempts the scheduler should make when modulo scheduling a loop",
 173          40, 0, 0)
 174
 175 DEFPARAM(PARAM_LARGE_FUNCTION_INSNS,
 176          "large-function-insns",
 177          "The size of function body to be considered large",
 178          2700, 0, 0)
 179 DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH,
 180          "large-function-growth",
 181          "Maximal growth due to inlining of large function (in percent)",
 182          100, 0, 0)
 183 DEFPARAM(PARAM_LARGE_UNIT_INSNS,
 184          "large-unit-insns",
 185          "The size of translation unit to be considered large",
 186          10000, 0, 0)
 187 DEFPARAM(PARAM_INLINE_UNIT_GROWTH,
 188          "inline-unit-growth",
 189          "How much can given compilation unit grow because of the inlining (in percent)",
 190          30, 0, 0)
 191 DEFPARAM(PARAM_IPCP_UNIT_GROWTH,
 192          "ipcp-unit-growth",
 193          "How much can given compilation unit grow because of the interprocedural constant propagation (in percent)",
 194          10, 0, 0)
 195 DEFPARAM(PARAM_EARLY_INLINING_INSNS,
 196          "early-inlining-insns",
 197          "Maximal estimated growth of function body caused by early inlining of single call",
 198          11, 0, 0)
 199 DEFPARAM(PARAM_LARGE_STACK_FRAME,
 200          "large-stack-frame",
 201          "The size of stack frame to be considered large",
 202          256, 0, 0)
 203 DEFPARAM(PARAM_STACK_FRAME_GROWTH,
 204          "large-stack-frame-growth",
 205          "Maximal stack frame growth due to inlining (in percent)",
 206          1000, 0, 0)
 207
 208 /* The GCSE optimization will be disabled if it would require
 209    significantly more memory than this value.  */
 210 DEFPARAM(PARAM_MAX_GCSE_MEMORY,
 211          "max-gcse-memory",
 212          "The maximum amount of memory to be allocated by GCSE",
 213          50 * 1024 * 1024, 0, 0)
 214
 215 /* The GCSE optimization of an expression will avoided if the ratio of
 216    insertions to deletions is greater than this value.  */
 217 DEFPARAM(PARAM_MAX_GCSE_INSERTION_RATIO,
 218          "max-gcse-insertion-ratio",
 219          "The maximum ratio of insertions to deletions of expressions in GCSE",
 220          20, 0, 0)
 221
 222 /* This is the threshold ratio when to perform partial redundancy
 223    elimination after reload. We perform partial redundancy elimination
 224    when the following holds:
 225    (Redundant load execution count)
 226    ------------------------------- >= GCSE_AFTER_RELOAD_PARTIAL_FRACTION
 227    (Added loads execution count)                                          */
 228 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_PARTIAL_FRACTION,
 229         "gcse-after-reload-partial-fraction",
 230         "The threshold ratio for performing partial redundancy elimination after reload",
 231         3, 0, 0)
 232 /* This is the threshold ratio of the critical edges execution count compared to
 233    the redundant loads execution count that permits performing the load
 234    redundancy elimination in gcse after reload.  */
 235 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_CRITICAL_FRACTION,
 236         "gcse-after-reload-critical-fraction",
 237         "The threshold ratio of critical edges execution count that permit performing redundancy elimination after reload",
 238         10, 0, 0)
 239
 240 /* GCSE will use GCSE_COST_DISTANCE_RATION as a scaling factor
 241    to calculate maximum distance for which an expression is allowed to move
 242    from its rtx_cost.  */
 243 DEFPARAM(PARAM_GCSE_COST_DISTANCE_RATIO,
 244          "gcse-cost-distance-ratio",
 245          "Scaling factor in calculation of maximum distance an expression can be moved by GCSE optimizations",
 246          10, 0, 0)
 247 /* GCSE won't restrict distance for which an expression with rtx_cost greater
 248    than COSTS_N_INSN(GCSE_UNRESTRICTED_COST) is allowed to move.  */
 249 DEFPARAM(PARAM_GCSE_UNRESTRICTED_COST,
 250          "gcse-unrestricted-cost",
 251          "Cost at which GCSE optimizations will not constraint the distance an expression can travel",
 252          3, 0, 0)
 253
 254 /* How deep from a given basic block the dominator tree should be searched
 255    for expressions to hoist to the block.  The value of 0 will avoid limiting
 256    the search.  */
 257 DEFPARAM(PARAM_MAX_HOIST_DEPTH,
 258          "max-hoist-depth",
 259          "Maximum depth of search in the dominator tree for expressions to hoist",
 260          30, 0, 0)
 261
 262 /* This parameter limits the number of insns in a loop that will be unrolled,
 263    and by how much the loop is unrolled.
 264
 265    This limit should be at most half of the peeling limits:  loop unroller
 266    decides to not unroll loops that iterate fewer than 2*number of allowed
 267    unrollings and thus we would have loops that are neither peeled or unrolled
 268    otherwise.  */
 269 DEFPARAM(PARAM_MAX_UNROLLED_INSNS,
 270          "max-unrolled-insns",
 271          "The maximum number of instructions to consider to unroll in a loop",
 272          200, 0, 0)
 273 /* This parameter limits how many times the loop is unrolled depending
 274    on number of insns really executed in each iteration.  */
 275 DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS,
 276          "max-average-unrolled-insns",
 277          "The maximum number of instructions to consider to unroll in a loop on average",
 278          80, 0, 0)
 279 /* The maximum number of unrollings of a single loop.  */
 280 DEFPARAM(PARAM_MAX_UNROLL_TIMES,
 281         "max-unroll-times",
 282         "The maximum number of unrollings of a single loop",
 283         8, 0, 0)
 284 /* The maximum number of insns of a peeled loop.  */
 285 DEFPARAM(PARAM_MAX_PEELED_INSNS,
 286         "max-peeled-insns",
 287         "The maximum number of insns of a peeled loop",
 288         400, 0, 0)
 289 /* The maximum number of peelings of a single loop.  */
 290 DEFPARAM(PARAM_MAX_PEEL_TIMES,
 291         "max-peel-times",
 292         "The maximum number of peelings of a single loop",
 293         16, 0, 0)
 294 /* The maximum number of insns of a peeled loop.  */
 295 DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS,
 296         "max-completely-peeled-insns",
 297         "The maximum number of insns of a completely peeled loop",
 298         400, 0, 0)
 299 /* The maximum number of peelings of a single loop that is peeled completely.  */
 300 DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES,
 301         "max-completely-peel-times",
 302         "The maximum number of peelings of a single loop that is peeled completely",
 303         16, 0, 0)
 304 /* The maximum number of insns of a peeled loop that rolls only once.  */
 305 DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS,
 306         "max-once-peeled-insns",
 307         "The maximum number of insns of a peeled loop that rolls only once",
 308         400, 0, 0)
 309 /* The maximum depth of a loop nest we completely peel.  */
 310 DEFPARAM(PARAM_MAX_UNROLL_ITERATIONS,
 311          "max-completely-peel-loop-nest-depth",
 312          "The maximum depth of a loop nest we completely peel",
 313          8, 0, 0)
 314
 315 /* The maximum number of insns of an unswitched loop.  */
 316 DEFPARAM(PARAM_MAX_UNSWITCH_INSNS,
 317         "max-unswitch-insns",
 318         "The maximum number of insns of an unswitched loop",
 319         50, 0, 0)
 320 /* The maximum level of recursion in unswitch_single_loop.  */
 321 DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL,
 322         "max-unswitch-level",
 323         "The maximum number of unswitchings in a single loop",
 324         3, 0, 0)
 325
 326 /* The maximum number of iterations of a loop the brute force algorithm
 327    for analysis of # of iterations of the loop tries to evaluate.  */
 328 DEFPARAM(PARAM_MAX_ITERATIONS_TO_TRACK,
 329         "max-iterations-to-track",
 330         "Bound on the number of iterations the brute force # of iterations analysis algorithm evaluates",
 331         1000, 0, 0)
 332 /* A cutoff to avoid costly computations of the number of iterations in
 333    the doloop transformation.  */
 334 DEFPARAM(PARAM_MAX_ITERATIONS_COMPUTATION_COST,
 335         "max-iterations-computation-cost",
 336         "Bound on the cost of an expression to compute the number of iterations",
 337         10, 0, 0)
 338
 339 /* This parameter is used to tune SMS MAX II calculations.  */
 340 DEFPARAM(PARAM_SMS_MAX_II_FACTOR,
 341          "sms-max-ii-factor",
 342          "A factor for tuning the upper bound that swing modulo scheduler uses for scheduling a loop",
 343          100, 0, 0)
 344 /* The minimum value of stage count that swing modulo scheduler will generate.  */
 345 DEFPARAM(PARAM_SMS_MIN_SC,
 346         "sms-min-sc",
 347         "The minimum value of stage count that swing modulo scheduler will generate.",
 348         2, 1, 1)
 349 DEFPARAM(PARAM_SMS_DFA_HISTORY,
 350          "sms-dfa-history",
 351          "The number of cycles the swing modulo scheduler considers when checking conflicts using DFA",
 352          0, 0, 0)
 353 DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD,
 354          "sms-loop-average-count-threshold",
 355          "A threshold on the average loop count considered by the swing modulo scheduler",
 356          0, 0, 0)
 357
 358 DEFPARAM(HOT_BB_COUNT_FRACTION,
 359          "hot-bb-count-fraction",
 360          "Select fraction of the maximal count of repetitions of basic block in program given basic block needs to have to be considered hot",
 361          10000, 0, 0)
 362 DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
 363          "hot-bb-frequency-fraction",
 364          "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot",
 365          1000, 0, 0)
 366
 367 DEFPARAM (PARAM_ALIGN_THRESHOLD,
 368           "align-threshold",
 369           "Select fraction of the maximal frequency of executions of basic block in function given basic block get alignment",
 370           100, 0, 0)
 371
 372 DEFPARAM (PARAM_ALIGN_LOOP_ITERATIONS,
 373           "align-loop-iterations",
 374           "Loops iterating at least selected number of iterations will get loop alignement.",
 375           4, 0, 0)
 376
 377 /* For guessed profiles, the loops having unknown number of iterations
 378    are predicted to iterate relatively few (10) times at average.
 379    For functions containing one loop with large known number of iterations
 380    and other loops having unbounded loops we would end up predicting all
 381    the other loops cold that is not usually the case.  So we need to artificially
 382    flatten the profile.
 383
 384    We need to cut the maximal predicted iterations to large enough iterations
 385    so the loop appears important, but safely within HOT_BB_COUNT_FRACTION
 386    range.  */
 387
 388 DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS,
 389          "max-predicted-iterations",
 390          "The maximum number of loop iterations we predict statically",
 391          100, 0, 0)
 392 DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
 393          "tracer-dynamic-coverage-feedback",
 394          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available",
 395          95, 0, 100)
 396 DEFPARAM(TRACER_DYNAMIC_COVERAGE,
 397          "tracer-dynamic-coverage",
 398          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available",
 399          75, 0, 100)
 400 DEFPARAM(TRACER_MAX_CODE_GROWTH,
 401          "tracer-max-code-growth",
 402          "Maximal code growth caused by tail duplication (in percent)",
 403          100, 0, 0)
 404 DEFPARAM(TRACER_MIN_BRANCH_RATIO,
 405          "tracer-min-branch-ratio",
 406          "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent)",
 407          10, 0, 100)
 408 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
 409          "tracer-min-branch-probability-feedback",
 410          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available",
 411          80, 0, 100)
 412 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
 413          "tracer-min-branch-probability",
 414          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available",
 415          50, 0, 100)
 416
 417 /* The maximum number of incoming edges to consider for crossjumping.  */
 418 DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
 419          "max-crossjump-edges",
 420          "The maximum number of incoming edges to consider for crossjumping",
 421          100, 0, 0)
 422
 423 /* The minimum number of matching instructions to consider for crossjumping.  */
 424 DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS,
 425      "min-crossjump-insns",
 426      "The minimum number of matching instructions to consider for crossjumping",
 427      5, 0, 0)
 428
 429 /* The maximum number expansion factor when copying basic blocks.  */
 430 DEFPARAM(PARAM_MAX_GROW_COPY_BB_INSNS,
 431      "max-grow-copy-bb-insns",
 432      "The maximum expansion factor when copying basic blocks",
 433      8, 0, 0)
 434
 435 /* The maximum number of insns to duplicate when unfactoring computed gotos.  */
 436 DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS,
 437      "max-goto-duplication-insns",
 438      "The maximum number of insns to duplicate when unfactoring computed gotos",
 439      8, 0, 0)
 440
 441 /* The maximum length of path considered in cse.  */
 442 DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
 443          "max-cse-path-length",
 444          "The maximum length of path considered in cse",
 445          10, 0, 0)
 446 DEFPARAM(PARAM_MAX_CSE_INSNS,
 447          "max-cse-insns",
 448          "The maximum instructions CSE process before flushing",
 449          1000, 0, 0)
 450
 451 /* The cost of expression in loop invariant motion that is considered
 452    expensive.  */
 453 DEFPARAM(PARAM_LIM_EXPENSIVE,
 454          "lim-expensive",
 455          "The minimum cost of an expensive expression in the loop invariant motion",
 456          20, 0, 0)
 457
 458 /* Bound on number of candidates for induction variables below that
 459    all candidates are considered for each use in induction variable
 460    optimizations.  */
 461
 462 DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND,
 463          "iv-consider-all-candidates-bound",
 464          "Bound on number of candidates below that all candidates are considered in iv optimizations",
 465          30, 0, 0)
 466
 467 /* The induction variable optimizations give up on loops that contain more
 468    induction variable uses.  */
 469
 470 DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES,
 471          "iv-max-considered-uses",
 472          "Bound on number of iv uses in loop optimized in iv optimizations",
 473          250, 0, 0)
 474
 475 /* If there are at most this number of ivs in the set, try removing unnecessary
 476    ivs from the set always.  */
 477
 478 DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND,
 479          "iv-always-prune-cand-set-bound",
 480          "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization",
 481          10, 0, 0)
 482
 483 DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE,
 484          "scev-max-expr-size",
 485          "Bound on size of expressions used in the scalar evolutions analyzer",
 486          100, 0, 0)
 487
 488 DEFPARAM(PARAM_SCEV_MAX_EXPR_COMPLEXITY,
 489          "scev-max-expr-complexity",
 490          "Bound on the complexity of the expressions in the scalar evolutions analyzer",
 491          10, 0, 0)
 492
 493 DEFPARAM(PARAM_OMEGA_MAX_VARS,
 494          "omega-max-vars",
 495          "Bound on the number of variables in Omega constraint systems",
 496          128, 0, 0)
 497
 498 DEFPARAM(PARAM_OMEGA_MAX_GEQS,
 499          "omega-max-geqs",
 500          "Bound on the number of inequalities in Omega constraint systems",
 501          256, 0, 0)
 502
 503 DEFPARAM(PARAM_OMEGA_MAX_EQS,
 504          "omega-max-eqs",
 505          "Bound on the number of equalities in Omega constraint systems",
 506          128, 0, 0)
 507
 508 DEFPARAM(PARAM_OMEGA_MAX_WILD_CARDS,
 509          "omega-max-wild-cards",
 510          "Bound on the number of wild cards in Omega constraint systems",
 511          18, 0, 0)
 512
 513 DEFPARAM(PARAM_OMEGA_HASH_TABLE_SIZE,
 514          "omega-hash-table-size",
 515          "Bound on the size of the hash table in Omega constraint systems",
 516          550, 0, 0)
 517
 518 DEFPARAM(PARAM_OMEGA_MAX_KEYS,
 519          "omega-max-keys",
 520          "Bound on the number of keys in Omega constraint systems",
 521          500, 0, 0)
 522
 523 DEFPARAM(PARAM_OMEGA_ELIMINATE_REDUNDANT_CONSTRAINTS,
 524          "omega-eliminate-redundant-constraints",
 525          "When set to 1, use expensive methods to eliminate all redundant constraints",
 526          0, 0, 1)
 527
 528 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIGNMENT_CHECKS,
 529          "vect-max-version-for-alignment-checks",
 530          "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alignment check",
 531          6, 0, 0)
 532
 533 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS,
 534          "vect-max-version-for-alias-checks",
 535          "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alias check",
 536          10, 0, 0)
 537
 538 DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS,
 539          "max-cselib-memory-locations",
 540          "The maximum memory locations recorded by cselib",
 541          500, 0, 0)
 542
 543 #ifdef ENABLE_GC_ALWAYS_COLLECT
 544 # define GGC_MIN_EXPAND_DEFAULT 0
 545 # define GGC_MIN_HEAPSIZE_DEFAULT 0
 546 #else
 547 # define GGC_MIN_EXPAND_DEFAULT 30
 548 # define GGC_MIN_HEAPSIZE_DEFAULT 4096
 549 #endif
 550
 551 DEFPARAM(GGC_MIN_EXPAND,
 552          "ggc-min-expand",
 553          "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap",
 554          GGC_MIN_EXPAND_DEFAULT, 0, 0)
 555
 556 DEFPARAM(GGC_MIN_HEAPSIZE,
 557          "ggc-min-heapsize",
 558          "Minimum heap size before we start collecting garbage, in kilobytes",
 559          GGC_MIN_HEAPSIZE_DEFAULT, 0, 0)
 560
 561 #undef GGC_MIN_EXPAND_DEFAULT
 562 #undef GGC_MIN_HEAPSIZE_DEFAULT
 563
 564 DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
 565          "max-reload-search-insns",
 566          "The maximum number of instructions to search backward when looking for equivalent reload",
 567          100, 0, 0)
 568
 569 DEFPARAM(PARAM_SINK_FREQUENCY_THRESHOLD,
 570          "sink-frequency-threshold",
 571          "Target block's relative execution frequency (as a percentage) required to sink a statement",
 572          75, 0, 100)
 573
 574 DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS,
 575          "max-sched-region-blocks",
 576          "The maximum number of blocks in a region to be considered for interblock scheduling",
 577          10, 0, 0)
 578
 579 DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS,
 580          "max-sched-region-insns",
 581          "The maximum number of insns in a region to be considered for interblock scheduling",
 582          100, 0, 0)
 583
 584 DEFPARAM(PARAM_MAX_PIPELINE_REGION_BLOCKS,
 585          "max-pipeline-region-blocks",
 586          "The maximum number of blocks in a region to be considered for interblock scheduling",
 587          15, 0, 0)
 588
 589 DEFPARAM(PARAM_MAX_PIPELINE_REGION_INSNS,
 590          "max-pipeline-region-insns",
 591          "The maximum number of insns in a region to be considered for interblock scheduling",
 592          200, 0, 0)
 593
 594 DEFPARAM(PARAM_MIN_SPEC_PROB,
 595          "min-spec-prob",
 596          "The minimum probability of reaching a source block for interblock speculative scheduling",
 597          40, 0, 0)
 598
 599 DEFPARAM(PARAM_MAX_SCHED_EXTEND_REGIONS_ITERS,
 600          "max-sched-extend-regions-iters",
 601          "The maximum number of iterations through CFG to extend regions",
 602          0, 0, 0)
 603
 604 DEFPARAM(PARAM_MAX_SCHED_INSN_CONFLICT_DELAY,
 605          "max-sched-insn-conflict-delay",
 606          "The maximum conflict delay for an insn to be considered for speculative motion",
 607          3, 1, 10)
 608
 609 DEFPARAM(PARAM_SCHED_SPEC_PROB_CUTOFF,
 610          "sched-spec-prob-cutoff",
 611          "The minimal probability of speculation success (in percents), so that speculative insn will be scheduled.",
 612          40, 0, 100)
 613
 614 DEFPARAM(PARAM_SELSCHED_MAX_LOOKAHEAD,
 615          "selsched-max-lookahead",
 616          "The maximum size of the lookahead window of selective scheduling",
 617          50, 0, 0)
 618
 619 DEFPARAM(PARAM_SELSCHED_MAX_SCHED_TIMES,
 620          "selsched-max-sched-times",
 621          "Maximum number of times that an insn could be scheduled",
 622          2, 0, 0)
 623
 624 DEFPARAM(PARAM_SELSCHED_INSNS_TO_RENAME,
 625          "selsched-insns-to-rename",
 626          "Maximum number of instructions in the ready list that are considered eligible for renaming",
 627          2, 0, 0)
 628
 629 DEFPARAM (PARAM_SCHED_MEM_TRUE_DEP_COST,
 630           "sched-mem-true-dep-cost",
 631           "Minimal distance between possibly conflicting store and load",
 632           1, 0, 0)
 633
 634 DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
 635          "max-last-value-rtl",
 636          "The maximum number of RTL nodes that can be recorded as combiner's last value",
 637          10000, 0, 0)
 638
 639 /* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
 640    {signed,unsigned} integral types.  This determines N.
 641    Experimentation shows 256 to be a good value.  */
 642 DEFPARAM (PARAM_INTEGER_SHARE_LIMIT,
 643           "integer-share-limit",
 644           "The upper bound for sharing integer constants",
 645           256, 2, 2)
 646
 647 /* Incremental SSA updates for virtual operands may be very slow if
 648    there is a large number of mappings to process.  In those cases, it
 649    is faster to rewrite the virtual symbols from scratch as if they
 650    had been recently introduced.  This heuristic cannot be applied to
 651    SSA mappings for real SSA names, only symbols kept in FUD chains.
 652
 653    PARAM_MIN_VIRTUAL_MAPPINGS specifies the minimum number of virtual
 654    mappings that should be registered to trigger the heuristic.
 655
 656    PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO specifies the ratio between
 657    mappings and symbols.  If the number of virtual mappings is
 658    PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO bigger than the number of
 659    virtual symbols to be updated, then the updater switches to a full
 660    update for those symbols.  */
 661 DEFPARAM (PARAM_MIN_VIRTUAL_MAPPINGS,
 662           "min-virtual-mappings",
 663           "Minimum number of virtual mappings to consider switching to full virtual renames",
 664           100, 0, 0)
 665
 666 DEFPARAM (PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO,
 667           "virtual-mappings-ratio",
 668           "Ratio between virtual mappings and virtual symbols to do full virtual renames",
 669           3, 0, 0)
 670
 671 DEFPARAM (PARAM_SSP_BUFFER_SIZE,
 672           "ssp-buffer-size",
 673           "The lower bound for a buffer to be considered for stack smashing protection",
 674           8, 1, 0)
 675
 676 /* When we thread through a block we have to make copies of the
 677    statements within the block.  Clearly for large blocks the code
 678    duplication is bad.
 679
 680    PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number
 681    of statements and PHI nodes allowed in a block which is going to
 682    be duplicated for thread jumping purposes.
 683
 684    Some simple analysis showed that more than 99% of the jump
 685    threading opportunities are for blocks with less than 15
 686    statements.  So we can get the benefits of jump threading
 687    without excessive code bloat for pathological cases with the
 688    throttle set at 15 statements.  */
 689 DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS,
 690           "max-jump-thread-duplication-stmts",
 691           "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps",
 692           15, 0, 0)
 693
 694 /* This is the maximum number of fields a variable may have before the pointer analysis machinery
 695    will stop trying to treat it in a field-sensitive manner.
 696    There are programs out there with thousands of fields per structure, and handling them
 697    field-sensitively is not worth the cost.  */
 698 DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE,
 699           "max-fields-for-field-sensitive",
 700           "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable",
 701           0, 0, 0)
 702
 703 DEFPARAM(PARAM_MAX_SCHED_READY_INSNS,
 704          "max-sched-ready-insns",
 705          "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass",
 706          100, 0, 0)
 707
 708 /* This is the maximum number of active local stores RTL DSE will consider.  */
 709 DEFPARAM (PARAM_MAX_DSE_ACTIVE_LOCAL_STORES,
 710           "max-dse-active-local-stores",
 711           "Maximum number of active local stores in RTL dead store elimination",
 712           5000, 0, 0)
 713
 714 /* Prefetching and cache-optimizations related parameters.  Default values are
 715    usually set by machine description.  */
 716
 717 /* The number of insns executed before prefetch is completed.  */
 718
 719 DEFPARAM (PARAM_PREFETCH_LATENCY,
 720          "prefetch-latency",
 721          "The number of insns executed before prefetch is completed",
 722          200, 0, 0)
 723
 724 /* The number of prefetches that can run at the same time.  */
 725
 726 DEFPARAM (PARAM_SIMULTANEOUS_PREFETCHES,
 727           "simultaneous-prefetches",
 728           "The number of prefetches that can run at the same time",
 729           3, 0, 0)
 730
 731 /* The size of L1 cache in kB.  */
 732
 733 DEFPARAM (PARAM_L1_CACHE_SIZE,
 734           "l1-cache-size",
 735           "The size of L1 cache",
 736           64, 0, 0)
 737
 738 /* The size of L1 cache line in bytes.  */
 739
 740 DEFPARAM (PARAM_L1_CACHE_LINE_SIZE,
 741           "l1-cache-line-size",
 742           "The size of L1 cache line",
 743           32, 0, 0)
 744
 745 /* The size of L2 cache in kB.  */
 746
 747 DEFPARAM (PARAM_L2_CACHE_SIZE,
 748           "l2-cache-size",
 749           "The size of L2 cache",
 750           512, 0, 0)
 751
 752 /* Whether we should use canonical types rather than deep "structural"
 753    type checking.  Setting this value to 1 (the default) improves
 754    compilation performance in the C++ and Objective-C++ front end;
 755    this value should only be set to zero to work around bugs in the
 756    canonical type system by disabling it.  */
 757
 758 DEFPARAM (PARAM_USE_CANONICAL_TYPES,
 759           "use-canonical-types",
 760           "Whether to use canonical types",
 761           1, 0, 1)
 762
 763 DEFPARAM (PARAM_MAX_PARTIAL_ANTIC_LENGTH,
 764           "max-partial-antic-length",
 765           "Maximum length of partial antic set when performing tree pre optimization",
 766           100, 0, 0)
 767
 768 /* The following is used as a stop-gap limit for cases where really huge
 769    SCCs blow up memory and compile-time use too much.  If we hit this limit,
 770    SCCVN and such FRE and PRE will be not done at all for the current
 771    function.  */
 772
 773 DEFPARAM (PARAM_SCCVN_MAX_SCC_SIZE,
 774           "sccvn-max-scc-size",
 775           "Maximum size of a SCC before SCCVN stops processing a function",
 776           10000, 10, 0)
 777
 778 DEFPARAM (PARAM_IRA_MAX_LOOPS_NUM,
 779           "ira-max-loops-num",
 780           "Max loops number for regional RA",
 781           100, 0, 0)
 782
 783 DEFPARAM (PARAM_IRA_MAX_CONFLICT_TABLE_SIZE,
 784           "ira-max-conflict-table-size",
 785           "Max size of conflict table in MB",
 786           1000, 0, 0)
 787
 788 DEFPARAM (PARAM_IRA_LOOP_RESERVED_REGS,
 789           "ira-loop-reserved-regs",
 790           "The number of registers in each class kept unused by loop invariant motion",
 791           2, 0, 0)
 792
 793 /* Switch initialization conversion will refuse to create arrays that are
 794    bigger than this parameter times the number of switch branches.  */
 795
 796 DEFPARAM (PARAM_SWITCH_CONVERSION_BRANCH_RATIO,
 797           "switch-conversion-max-branch-ratio",
 798           "The maximum ratio between array size and switch branches for "
 799           "a switch conversion to take place",
 800           8, 1, 0)
 801
 802 /* Size of tiles when doing loop blocking.  */
 803
 804 DEFPARAM (PARAM_LOOP_BLOCK_TILE_SIZE,
 805           "loop-block-tile-size",
 806           "size of tiles for loop blocking",
 807           51, 0, 0)
 808
 809 /* Maximal number of parameters that we allow in a SCoP.  */
 810
 811 DEFPARAM (PARAM_GRAPHITE_MAX_NB_SCOP_PARAMS,
 812           "graphite-max-nb-scop-params",
 813           "maximum number of parameters in a SCoP",
 814           10, 0, 0)
 815
 816 /* Maximal number of basic blocks in the functions analyzed by Graphite.  */
 817
 818 DEFPARAM (PARAM_GRAPHITE_MAX_BBS_PER_FUNCTION,
 819           "graphite-max-bbs-per-function",
 820           "maximum number of basic blocks per function to be analyzed by Graphite",
 821           100, 0, 0)
 822
 823 /* Avoid data dependence analysis on very large loops.  */
 824 DEFPARAM (PARAM_LOOP_MAX_DATAREFS_FOR_DATADEPS,
 825           "loop-max-datarefs-for-datadeps",
 826           "Maximum number of datarefs in loop for building loop data dependencies",
 827           1000, 0, 0)
 828
 829 /* Avoid doing loop invariant motion on very large loops.  */
 830
 831 DEFPARAM (PARAM_LOOP_INVARIANT_MAX_BBS_IN_LOOP,
 832           "loop-invariant-max-bbs-in-loop",
 833           "Max basic blocks number in loop for loop invariant motion",
 834           10000, 0, 0)
 835
 836 /* Avoid SLP vectorization of large basic blocks.  */
 837 DEFPARAM (PARAM_SLP_MAX_INSNS_IN_BB,
 838           "slp-max-insns-in-bb",
 839           "Maximum number of instructions in basic block to be considered for SLP vectorization",
 840           1000, 0, 0)
 841
 842 DEFPARAM (PARAM_MIN_INSN_TO_PREFETCH_RATIO,
 843           "min-insn-to-prefetch-ratio",
 844           "Min. ratio of insns to prefetches to enable prefetching for "
 845           "a loop with an unknown trip count",
 846           9, 0, 0)
 847
 848 DEFPARAM (PARAM_PREFETCH_MIN_INSN_TO_MEM_RATIO,
 849           "prefetch-min-insn-to-mem-ratio",
 850           "Min. ratio of insns to mem ops to enable prefetching in a loop",
 851           3, 0, 0)
 852
 853 /* Set maximum hash table size for var tracking.  */
 854
 855 DEFPARAM (PARAM_MAX_VARTRACK_SIZE,
 856           "max-vartrack-size",
 857           "Max. size of var tracking hash tables",
 858           50000000, 0, 0)
 859
 860 /* Set maximum recursion depth for var tracking expression expansion
 861    and resolution.  */
 862
 863 DEFPARAM (PARAM_MAX_VARTRACK_EXPR_DEPTH,
 864           "max-vartrack-expr-depth",
 865           "Max. recursion depth for expanding var tracking expressions",
 866           12, 0, 0)
 867
 868 /* Set minimum insn uid for non-debug insns.  */
 869
 870 DEFPARAM (PARAM_MIN_NONDEBUG_INSN_UID,
 871           "min-nondebug-insn-uid",
 872           "The minimum UID to be used for a nondebug insn",
 873           0, 1, 0)
 874
 875 DEFPARAM (PARAM_IPA_SRA_PTR_GROWTH_FACTOR,
 876           "ipa-sra-ptr-growth-factor",
 877           "Maximum allowed growth of size of new parameters ipa-sra replaces "
 878           "a pointer to an aggregate with",
 879           2, 0, 0)
 880
 881 DEFPARAM (PARAM_TM_MAX_AGGREGATE_SIZE,
 882           "tm-max-aggregate-size",
 883           "Size in bytes after which thread-local aggregates should be "
 884           "instrumented with the logging functions instead of save/restore "
 885           "pairs",
 886           9, 0, 0)
 887
 888 DEFPARAM (PARAM_IPA_CP_VALUE_LIST_SIZE,
 889           "ipa-cp-value-list-size",
 890           "Maximum size of a list of values associated with each parameter for "
 891           "interprocedural constant propagation",
 892           8, 0, 0)
 893
 894 DEFPARAM (PARAM_IPA_CP_EVAL_THRESHOLD,
 895           "ipa-cp-eval-threshold",
 896           "Threshold ipa-cp opportunity evaluation that is still considered "
 897           "beneficial to clone.",
 898           500, 0, 0)
 899
 900 /* WHOPR partitioning configuration.  */
 901
 902 DEFPARAM (PARAM_LTO_PARTITIONS,
 903           "lto-partitions",
 904           "Number of partitions the program should be split to",
 905           32, 1, 0)
 906
 907 DEFPARAM (MIN_PARTITION_SIZE,
 908           "lto-min-partition",
 909           "Minimal size of a partition for LTO (in estimated instructions)",
 910           1000, 0, 0)
 911
 912 /* Diagnostic parameters.  */
 913
 914 DEFPARAM (CXX_MAX_NAMESPACES_FOR_DIAGNOSTIC_HELP,
 915           "cxx-max-namespaces-for-diagnostic-help",
 916           "Maximum number of namespaces to search for alternatives when "
 917           "name lookup fails",
 918           1000, 0, 0)
 919
 920 /* Maximum number of conditional store pairs that can be sunk.  */
 921 DEFPARAM (PARAM_MAX_STORES_TO_SINK,
 922           "max-stores-to-sink",
 923           "Maximum number of conditional store pairs that can be sunk",
 924           2, 0, 0)
 925
 926 /* Override CASE_VALUES_THRESHOLD of when to switch from doing switch
 927    statements via if statements to using a table jump operation.  If the value
 928    is 0, the default CASE_VALUES_THRESHOLD will be used.  */
 929 DEFPARAM (PARAM_CASE_VALUES_THRESHOLD,
 930           "case-values-threshold",
 931           "The smallest number of different values for which it is best to "
 932           "use a jump-table instead of a tree of conditional branches, "
 933           "if 0, use the default for the machine",
 934           0, 0, 0)
 935
 936 /* Data race flags for C++0x memory model compliance.  */
 937 DEFPARAM (PARAM_ALLOW_LOAD_DATA_RACES,
 938           "allow-load-data-races",
 939           "Allow new data races on loads to be introduced",
 940           1, 0, 1)
 941
 942 DEFPARAM (PARAM_ALLOW_STORE_DATA_RACES,
 943           "allow-store-data-races",
 944           "Allow new data races on stores to be introduced",
 945           1, 0, 1)
 946
 947 DEFPARAM (PARAM_ALLOW_PACKED_LOAD_DATA_RACES,
 948           "allow-packed-load-data-races",
 949           "Allow new data races on packed data loads to be introduced",
 950           1, 0, 1)
 951
 952 DEFPARAM (PARAM_ALLOW_PACKED_STORE_DATA_RACES,
 953           "allow-packed-store-data-races",
 954           "Allow new data races on packed data stores to be introduced",
 955           1, 0, 1)
 956
 957 /* Reassociation width to be used by tree reassoc optimization.  */
 958 DEFPARAM (PARAM_TREE_REASSOC_WIDTH,
 959           "tree-reassoc-width",
 960           "Set the maximum number of instructions executed in parallel in "
 961           "reassociated tree. If 0, use the target dependent heuristic.",
 962           0, 0, 0)
 963
 964 DEFPARAM (PARAM_MAX_TAIL_MERGE_COMPARISONS,
 965           "max-tail-merge-comparisons",
 966           "Maximum amount of similar bbs to compare a bb with",
 967           10, 0, 0)
 968
 969 DEFPARAM (PARAM_MAX_TAIL_MERGE_ITERATIONS,
 970           "max-tail-merge-iterations",
 971           "Maximum amount of iterations of the pass over a function",
 972           2, 0, 0)
 973
 974 /* Maximum number of strings for which strlen optimization pass will
 975    track string lenths.  */
 976 DEFPARAM (PARAM_MAX_TRACKED_STRLENS,
 977           "max-tracked-strlens",
 978           "Maximum number of strings for which strlen optimization pass will "
 979           "track string lengths",
 980           1000, 0, 0)
 981
 982 /* Keep this in sync with the sched_pressure_algorithm enum.  */
 983 DEFPARAM (PARAM_SCHED_PRESSURE_ALGORITHM,
 984           "sched-pressure-algorithm",
 985           "Which -fsched-pressure algorithm to apply",
 986           1, 1, 2)
 987
 988 /*
 989 Local variables:
 990 mode:c
 991 End:
 992 */