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 /* 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 compilatoin 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 DEFPARAM(PARAM_LARGE_FUNCTION_INSNS,
 169          "large-function-insns",
 170          "The size of function body to be considered large",
 171          2700, 0, 0)
 172 DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH,
 173          "large-function-growth",
 174          "Maximal growth due to inlining of large function (in percent)",
 175          100, 0, 0)
 176 DEFPARAM(PARAM_LARGE_UNIT_INSNS,
 177          "large-unit-insns",
 178          "The size of translation unit to be considered large",
 179          10000, 0, 0)
 180 DEFPARAM(PARAM_INLINE_UNIT_GROWTH,
 181          "inline-unit-growth",
 182          "How much can given compilation unit grow because of the inlining (in percent)",
 183          30, 0, 0)
 184 DEFPARAM(PARAM_IPCP_UNIT_GROWTH,
 185          "ipcp-unit-growth",
 186          "How much can given compilation unit grow because of the interprocedural constant propagation (in percent)",
 187          10, 0, 0)
 188 DEFPARAM(PARAM_EARLY_INLINING_INSNS,
 189          "early-inlining-insns",
 190          "Maximal estimated growth of function body caused by early inlining of single call",
 191          11, 0, 0)
 192 DEFPARAM(PARAM_LARGE_STACK_FRAME,
 193          "large-stack-frame",
 194          "The size of stack frame to be considered large",
 195          256, 0, 0)
 196 DEFPARAM(PARAM_STACK_FRAME_GROWTH,
 197          "large-stack-frame-growth",
 198          "Maximal stack frame growth due to inlining (in percent)",
 199          1000, 0, 0)
 200
 201 /* The GCSE optimization will be disabled if it would require
 202    significantly more memory than this value.  */
 203 DEFPARAM(PARAM_MAX_GCSE_MEMORY,
 204          "max-gcse-memory",
 205          "The maximum amount of memory to be allocated by GCSE",
 206          50 * 1024 * 1024, 0, 0)
 207
 208 /* The GCSE optimization of an expression will avoided if the ratio of
 209    insertions to deletions is greater than this value.  */
 210 DEFPARAM(PARAM_MAX_GCSE_INSERTION_RATIO,
 211          "max-gcse-insertion-ratio",
 212          "The maximum ratio of insertions to deletions of expressions in GCSE",
 213          20, 0, 0)
 214
 215 /* This is the threshold ratio when to perform partial redundancy
 216    elimination after reload. We perform partial redundancy elimination
 217    when the following holds:
 218    (Redundant load execution count)
 219    ------------------------------- >= GCSE_AFTER_RELOAD_PARTIAL_FRACTION
 220    (Added loads execution count)                                          */
 221 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_PARTIAL_FRACTION,
 222         "gcse-after-reload-partial-fraction",
 223         "The threshold ratio for performing partial redundancy elimination after reload",
 224         3, 0, 0)
 225 /* This is the threshold ratio of the critical edges execution count compared to
 226    the redundant loads execution count that permits performing the load
 227    redundancy elimination in gcse after reload.  */
 228 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_CRITICAL_FRACTION,
 229         "gcse-after-reload-critical-fraction",
 230         "The threshold ratio of critical edges execution count that permit performing redundancy elimination after reload",
 231         10, 0, 0)
 232
 233 /* GCSE will use GCSE_COST_DISTANCE_RATION as a scaling factor
 234    to calculate maximum distance for which an expression is allowed to move
 235    from its rtx_cost.  */
 236 DEFPARAM(PARAM_GCSE_COST_DISTANCE_RATIO,
 237          "gcse-cost-distance-ratio",
 238          "Scaling factor in calculation of maximum distance an expression can be moved by GCSE optimizations",
 239          10, 0, 0)
 240 /* GCSE won't restrict distance for which an expression with rtx_cost greater
 241    than COSTS_N_INSN(GCSE_UNRESTRICTED_COST) is allowed to move.  */
 242 DEFPARAM(PARAM_GCSE_UNRESTRICTED_COST,
 243          "gcse-unrestricted-cost",
 244          "Cost at which GCSE optimizations will not constraint the distance an expression can travel",
 245          3, 0, 0)
 246
 247 /* How deep from a given basic block the dominator tree should be searched
 248    for expressions to hoist to the block.  The value of 0 will avoid limiting
 249    the search.  */
 250 DEFPARAM(PARAM_MAX_HOIST_DEPTH,
 251          "max-hoist-depth",
 252          "Maximum depth of search in the dominator tree for expressions to hoist",
 253          30, 0, 0)
 254
 255 /* This parameter limits the number of insns in a loop that will be unrolled,
 256    and by how much the loop is unrolled.
 257
 258    This limit should be at most half of the peeling limits:  loop unroller
 259    decides to not unroll loops that iterate fewer than 2*number of allowed
 260    unrollings and thus we would have loops that are neither peeled or unrolled
 261    otherwise.  */
 262 DEFPARAM(PARAM_MAX_UNROLLED_INSNS,
 263          "max-unrolled-insns",
 264          "The maximum number of instructions to consider to unroll in a loop",
 265          200, 0, 0)
 266 /* This parameter limits how many times the loop is unrolled depending
 267    on number of insns really executed in each iteration.  */
 268 DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS,
 269          "max-average-unrolled-insns",
 270          "The maximum number of instructions to consider to unroll in a loop on average",
 271          80, 0, 0)
 272 /* The maximum number of unrollings of a single loop.  */
 273 DEFPARAM(PARAM_MAX_UNROLL_TIMES,
 274         "max-unroll-times",
 275         "The maximum number of unrollings of a single loop",
 276         8, 0, 0)
 277 /* The maximum number of insns of a peeled loop.  */
 278 DEFPARAM(PARAM_MAX_PEELED_INSNS,
 279         "max-peeled-insns",
 280         "The maximum number of insns of a peeled loop",
 281         400, 0, 0)
 282 /* The maximum number of peelings of a single loop.  */
 283 DEFPARAM(PARAM_MAX_PEEL_TIMES,
 284         "max-peel-times",
 285         "The maximum number of peelings of a single loop",
 286         16, 0, 0)
 287 /* The maximum number of insns of a peeled loop.  */
 288 DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS,
 289         "max-completely-peeled-insns",
 290         "The maximum number of insns of a completely peeled loop",
 291         400, 0, 0)
 292 /* The maximum number of peelings of a single loop that is peeled completely.  */
 293 DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES,
 294         "max-completely-peel-times",
 295         "The maximum number of peelings of a single loop that is peeled completely",
 296         16, 0, 0)
 297 /* The maximum number of insns of a peeled loop that rolls only once.  */
 298 DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS,
 299         "max-once-peeled-insns",
 300         "The maximum number of insns of a peeled loop that rolls only once",
 301         400, 0, 0)
 302 /* The maximum depth of a loop nest we completely peel.  */
 303 DEFPARAM(PARAM_MAX_UNROLL_ITERATIONS,
 304          "max-completely-peel-loop-nest-depth",
 305          "The maximum depth of a loop nest we completely peel",
 306          8, 0, 0)
 307
 308 /* The maximum number of insns of an unswitched loop.  */
 309 DEFPARAM(PARAM_MAX_UNSWITCH_INSNS,
 310         "max-unswitch-insns",
 311         "The maximum number of insns of an unswitched loop",
 312         50, 0, 0)
 313 /* The maximum level of recursion in unswitch_single_loop.  */
 314 DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL,
 315         "max-unswitch-level",
 316         "The maximum number of unswitchings in a single loop",
 317         3, 0, 0)
 318
 319 /* The maximum number of iterations of a loop the brute force algorithm
 320    for analysis of # of iterations of the loop tries to evaluate.  */
 321 DEFPARAM(PARAM_MAX_ITERATIONS_TO_TRACK,
 322         "max-iterations-to-track",
 323         "Bound on the number of iterations the brute force # of iterations analysis algorithm evaluates",
 324         1000, 0, 0)
 325 /* A cutoff to avoid costly computations of the number of iterations in
 326    the doloop transformation.  */
 327 DEFPARAM(PARAM_MAX_ITERATIONS_COMPUTATION_COST,
 328         "max-iterations-computation-cost",
 329         "Bound on the cost of an expression to compute the number of iterations",
 330         10, 0, 0)
 331
 332 /* This parameter is used to tune SMS MAX II calculations.  */
 333 DEFPARAM(PARAM_SMS_MAX_II_FACTOR,
 334          "sms-max-ii-factor",
 335          "A factor for tuning the upper bound that swing modulo scheduler uses for scheduling a loop",
 336          100, 0, 0)
 337 /* The minimum value of stage count that swing modulo scheduler will generate.  */
 338 DEFPARAM(PARAM_SMS_MIN_SC,
 339         "sms-min-sc",
 340         "The minimum value of stage count that swing modulo scheduler will generate.",
 341         2, 1, 1)
 342 DEFPARAM(PARAM_SMS_DFA_HISTORY,
 343          "sms-dfa-history",
 344          "The number of cycles the swing modulo scheduler considers when checking conflicts using DFA",
 345          0, 0, 0)
 346 DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD,
 347          "sms-loop-average-count-threshold",
 348          "A threshold on the average loop count considered by the swing modulo scheduler",
 349          0, 0, 0)
 350
 351 DEFPARAM(HOT_BB_COUNT_FRACTION,
 352          "hot-bb-count-fraction",
 353          "Select fraction of the maximal count of repetitions of basic block in program given basic block needs to have to be considered hot",
 354          10000, 0, 0)
 355 DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
 356          "hot-bb-frequency-fraction",
 357          "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot",
 358          1000, 0, 0)
 359
 360 DEFPARAM (PARAM_ALIGN_THRESHOLD,
 361           "align-threshold",
 362           "Select fraction of the maximal frequency of executions of basic block in function given basic block get alignment",
 363           100, 0, 0)
 364
 365 DEFPARAM (PARAM_ALIGN_LOOP_ITERATIONS,
 366           "align-loop-iterations",
 367           "Loops iterating at least selected number of iterations will get loop alignement.",
 368           4, 0, 0)
 369
 370 /* For guessed profiles, the loops having unknown number of iterations
 371    are predicted to iterate relatively few (10) times at average.
 372    For functions containing one loop with large known number of iterations
 373    and other loops having unbounded loops we would end up predicting all
 374    the other loops cold that is not usually the case.  So we need to artificially
 375    flatten the profile.
 376
 377    We need to cut the maximal predicted iterations to large enough iterations
 378    so the loop appears important, but safely within HOT_BB_COUNT_FRACTION
 379    range.  */
 380
 381 DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS,
 382          "max-predicted-iterations",
 383          "The maximum number of loop iterations we predict statically",
 384          100, 0, 0)
 385 DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
 386          "tracer-dynamic-coverage-feedback",
 387          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available",
 388          95, 0, 100)
 389 DEFPARAM(TRACER_DYNAMIC_COVERAGE,
 390          "tracer-dynamic-coverage",
 391          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available",
 392          75, 0, 100)
 393 DEFPARAM(TRACER_MAX_CODE_GROWTH,
 394          "tracer-max-code-growth",
 395          "Maximal code growth caused by tail duplication (in percent)",
 396          100, 0, 0)
 397 DEFPARAM(TRACER_MIN_BRANCH_RATIO,
 398          "tracer-min-branch-ratio",
 399          "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent)",
 400          10, 0, 100)
 401 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
 402          "tracer-min-branch-probability-feedback",
 403          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available",
 404          80, 0, 100)
 405 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
 406          "tracer-min-branch-probability",
 407          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available",
 408          50, 0, 100)
 409
 410 /* The maximum number of incoming edges to consider for crossjumping.  */
 411 DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
 412          "max-crossjump-edges",
 413          "The maximum number of incoming edges to consider for crossjumping",
 414          100, 0, 0)
 415
 416 /* The minimum number of matching instructions to consider for crossjumping.  */
 417 DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS,
 418      "min-crossjump-insns",
 419      "The minimum number of matching instructions to consider for crossjumping",
 420      5, 0, 0)
 421
 422 /* The maximum number expansion factor when copying basic blocks.  */
 423 DEFPARAM(PARAM_MAX_GROW_COPY_BB_INSNS,
 424      "max-grow-copy-bb-insns",
 425      "The maximum expansion factor when copying basic blocks",
 426      8, 0, 0)
 427
 428 /* The maximum number of insns to duplicate when unfactoring computed gotos.  */
 429 DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS,
 430      "max-goto-duplication-insns",
 431      "The maximum number of insns to duplicate when unfactoring computed gotos",
 432      8, 0, 0)
 433
 434 /* The maximum length of path considered in cse.  */
 435 DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
 436          "max-cse-path-length",
 437          "The maximum length of path considered in cse",
 438          10, 0, 0)
 439 DEFPARAM(PARAM_MAX_CSE_INSNS,
 440          "max-cse-insns",
 441          "The maximum instructions CSE process before flushing",
 442          1000, 0, 0)
 443
 444 /* The cost of expression in loop invariant motion that is considered
 445    expensive.  */
 446 DEFPARAM(PARAM_LIM_EXPENSIVE,
 447          "lim-expensive",
 448          "The minimum cost of an expensive expression in the loop invariant motion",
 449          20, 0, 0)
 450
 451 /* Bound on number of candidates for induction variables below that
 452    all candidates are considered for each use in induction variable
 453    optimizations.  */
 454
 455 DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND,
 456          "iv-consider-all-candidates-bound",
 457          "Bound on number of candidates below that all candidates are considered in iv optimizations",
 458          30, 0, 0)
 459
 460 /* The induction variable optimizations give up on loops that contain more
 461    induction variable uses.  */
 462
 463 DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES,
 464          "iv-max-considered-uses",
 465          "Bound on number of iv uses in loop optimized in iv optimizations",
 466          250, 0, 0)
 467
 468 /* If there are at most this number of ivs in the set, try removing unnecessary
 469    ivs from the set always.  */
 470
 471 DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND,
 472          "iv-always-prune-cand-set-bound",
 473          "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization",
 474          10, 0, 0)
 475
 476 DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE,
 477          "scev-max-expr-size",
 478          "Bound on size of expressions used in the scalar evolutions analyzer",
 479          100, 0, 0)
 480
 481 DEFPARAM(PARAM_SCEV_MAX_EXPR_COMPLEXITY,
 482          "scev-max-expr-complexity",
 483          "Bound on the complexity of the expressions in the scalar evolutions analyzer",
 484          10, 0, 0)
 485
 486 DEFPARAM(PARAM_OMEGA_MAX_VARS,
 487          "omega-max-vars",
 488          "Bound on the number of variables in Omega constraint systems",
 489          128, 0, 0)
 490
 491 DEFPARAM(PARAM_OMEGA_MAX_GEQS,
 492          "omega-max-geqs",
 493          "Bound on the number of inequalities in Omega constraint systems",
 494          256, 0, 0)
 495
 496 DEFPARAM(PARAM_OMEGA_MAX_EQS,
 497          "omega-max-eqs",
 498          "Bound on the number of equalities in Omega constraint systems",
 499          128, 0, 0)
 500
 501 DEFPARAM(PARAM_OMEGA_MAX_WILD_CARDS,
 502          "omega-max-wild-cards",
 503          "Bound on the number of wild cards in Omega constraint systems",
 504          18, 0, 0)
 505
 506 DEFPARAM(PARAM_OMEGA_HASH_TABLE_SIZE,
 507          "omega-hash-table-size",
 508          "Bound on the size of the hash table in Omega constraint systems",
 509          550, 0, 0)
 510
 511 DEFPARAM(PARAM_OMEGA_MAX_KEYS,
 512          "omega-max-keys",
 513          "Bound on the number of keys in Omega constraint systems",
 514          500, 0, 0)
 515
 516 DEFPARAM(PARAM_OMEGA_ELIMINATE_REDUNDANT_CONSTRAINTS,
 517          "omega-eliminate-redundant-constraints",
 518          "When set to 1, use expensive methods to eliminate all redundant constraints",
 519          0, 0, 1)
 520
 521 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIGNMENT_CHECKS,
 522          "vect-max-version-for-alignment-checks",
 523          "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alignment check",
 524          6, 0, 0)
 525
 526 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS,
 527          "vect-max-version-for-alias-checks",
 528          "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alias check",
 529          10, 0, 0)
 530
 531 DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS,
 532          "max-cselib-memory-locations",
 533          "The maximum memory locations recorded by cselib",
 534          500, 0, 0)
 535
 536 #ifdef ENABLE_GC_ALWAYS_COLLECT
 537 # define GGC_MIN_EXPAND_DEFAULT 0
 538 # define GGC_MIN_HEAPSIZE_DEFAULT 0
 539 #else
 540 # define GGC_MIN_EXPAND_DEFAULT 30
 541 # define GGC_MIN_HEAPSIZE_DEFAULT 4096
 542 #endif
 543
 544 DEFPARAM(GGC_MIN_EXPAND,
 545          "ggc-min-expand",
 546          "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap",
 547          GGC_MIN_EXPAND_DEFAULT, 0, 0)
 548
 549 DEFPARAM(GGC_MIN_HEAPSIZE,
 550          "ggc-min-heapsize",
 551          "Minimum heap size before we start collecting garbage, in kilobytes",
 552          GGC_MIN_HEAPSIZE_DEFAULT, 0, 0)
 553
 554 #undef GGC_MIN_EXPAND_DEFAULT
 555 #undef GGC_MIN_HEAPSIZE_DEFAULT
 556
 557 DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
 558          "max-reload-search-insns",
 559          "The maximum number of instructions to search backward when looking for equivalent reload",
 560          100, 0, 0)
 561
 562 DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS,
 563          "max-sched-region-blocks",
 564          "The maximum number of blocks in a region to be considered for interblock scheduling",
 565          10, 0, 0)
 566
 567 DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS,
 568          "max-sched-region-insns",
 569          "The maximum number of insns in a region to be considered for interblock scheduling",
 570          100, 0, 0)
 571
 572 DEFPARAM(PARAM_MAX_PIPELINE_REGION_BLOCKS,
 573          "max-pipeline-region-blocks",
 574          "The maximum number of blocks in a region to be considered for interblock scheduling",
 575          15, 0, 0)
 576
 577 DEFPARAM(PARAM_MAX_PIPELINE_REGION_INSNS,
 578          "max-pipeline-region-insns",
 579          "The maximum number of insns in a region to be considered for interblock scheduling",
 580          200, 0, 0)
 581
 582 DEFPARAM(PARAM_MIN_SPEC_PROB,
 583          "min-spec-prob",
 584          "The minimum probability of reaching a source block for interblock speculative scheduling",
 585          40, 0, 0)
 586
 587 DEFPARAM(PARAM_MAX_SCHED_EXTEND_REGIONS_ITERS,
 588          "max-sched-extend-regions-iters",
 589          "The maximum number of iterations through CFG to extend regions",
 590          0, 0, 0)
 591
 592 DEFPARAM(PARAM_MAX_SCHED_INSN_CONFLICT_DELAY,
 593          "max-sched-insn-conflict-delay",
 594          "The maximum conflict delay for an insn to be considered for speculative motion",
 595          3, 1, 10)
 596
 597 DEFPARAM(PARAM_SCHED_SPEC_PROB_CUTOFF,
 598          "sched-spec-prob-cutoff",
 599          "The minimal probability of speculation success (in percents), so that speculative insn will be scheduled.",
 600          40, 0, 100)
 601
 602 DEFPARAM(PARAM_SELSCHED_MAX_LOOKAHEAD,
 603          "selsched-max-lookahead",
 604          "The maximum size of the lookahead window of selective scheduling",
 605          50, 0, 0)
 606
 607 DEFPARAM(PARAM_SELSCHED_MAX_SCHED_TIMES,
 608          "selsched-max-sched-times",
 609          "Maximum number of times that an insn could be scheduled",
 610          2, 0, 0)
 611
 612 DEFPARAM(PARAM_SELSCHED_INSNS_TO_RENAME,
 613          "selsched-insns-to-rename",
 614          "Maximum number of instructions in the ready list that are considered eligible for renaming",
 615          2, 0, 0)
 616
 617 DEFPARAM (PARAM_SCHED_MEM_TRUE_DEP_COST,
 618           "sched-mem-true-dep-cost",
 619           "Minimal distance between possibly conflicting store and load",
 620           1, 0, 0)
 621
 622 DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
 623          "max-last-value-rtl",
 624          "The maximum number of RTL nodes that can be recorded as combiner's last value",
 625          10000, 0, 0)
 626
 627 /* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
 628    {signed,unsigned} integral types.  This determines N.
 629    Experimentation shows 256 to be a good value.  */
 630 DEFPARAM (PARAM_INTEGER_SHARE_LIMIT,
 631           "integer-share-limit",
 632           "The upper bound for sharing integer constants",
 633           256, 2, 2)
 634
 635 /* Incremental SSA updates for virtual operands may be very slow if
 636    there is a large number of mappings to process.  In those cases, it
 637    is faster to rewrite the virtual symbols from scratch as if they
 638    had been recently introduced.  This heuristic cannot be applied to
 639    SSA mappings for real SSA names, only symbols kept in FUD chains.
 640
 641    PARAM_MIN_VIRTUAL_MAPPINGS specifies the minimum number of virtual
 642    mappings that should be registered to trigger the heuristic.
 643
 644    PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO specifies the ratio between
 645    mappings and symbols.  If the number of virtual mappings is
 646    PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO bigger than the number of
 647    virtual symbols to be updated, then the updater switches to a full
 648    update for those symbols.  */
 649 DEFPARAM (PARAM_MIN_VIRTUAL_MAPPINGS,
 650           "min-virtual-mappings",
 651           "Minimum number of virtual mappings to consider switching to full virtual renames",
 652           100, 0, 0)
 653
 654 DEFPARAM (PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO,
 655           "virtual-mappings-ratio",
 656           "Ratio between virtual mappings and virtual symbols to do full virtual renames",
 657           3, 0, 0)
 658
 659 DEFPARAM (PARAM_SSP_BUFFER_SIZE,
 660           "ssp-buffer-size",
 661           "The lower bound for a buffer to be considered for stack smashing protection",
 662           8, 1, 0)
 663
 664 /* When we thread through a block we have to make copies of the
 665    statements within the block.  Clearly for large blocks the code
 666    duplication is bad.
 667
 668    PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number
 669    of statements and PHI nodes allowed in a block which is going to
 670    be duplicated for thread jumping purposes.
 671
 672    Some simple analysis showed that more than 99% of the jump
 673    threading opportunities are for blocks with less than 15
 674    statements.  So we can get the benefits of jump threading
 675    without excessive code bloat for pathological cases with the
 676    throttle set at 15 statements.  */
 677 DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS,
 678           "max-jump-thread-duplication-stmts",
 679           "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps",
 680           15, 0, 0)
 681
 682 /* This is the maximum number of fields a variable may have before the pointer analysis machinery
 683    will stop trying to treat it in a field-sensitive manner.
 684    There are programs out there with thousands of fields per structure, and handling them
 685    field-sensitively is not worth the cost.  */
 686 DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE,
 687           "max-fields-for-field-sensitive",
 688           "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable",
 689           0, 0, 0)
 690
 691 DEFPARAM(PARAM_MAX_SCHED_READY_INSNS,
 692          "max-sched-ready-insns",
 693          "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass",
 694          100, 0, 0)
 695
 696 /* This is the maximum number of active local stores RTL DSE will consider.  */
 697 DEFPARAM (PARAM_MAX_DSE_ACTIVE_LOCAL_STORES,
 698           "max-dse-active-local-stores",
 699           "Maximum number of active local stores in RTL dead store elimination",
 700           5000, 0, 0)
 701
 702 /* Prefetching and cache-optimizations related parameters.  Default values are
 703    usually set by machine description.  */
 704
 705 /* The number of insns executed before prefetch is completed.  */
 706
 707 DEFPARAM (PARAM_PREFETCH_LATENCY,
 708          "prefetch-latency",
 709          "The number of insns executed before prefetch is completed",
 710          200, 0, 0)
 711
 712 /* The number of prefetches that can run at the same time.  */
 713
 714 DEFPARAM (PARAM_SIMULTANEOUS_PREFETCHES,
 715           "simultaneous-prefetches",
 716           "The number of prefetches that can run at the same time",
 717           3, 0, 0)
 718
 719 /* The size of L1 cache in kB.  */
 720
 721 DEFPARAM (PARAM_L1_CACHE_SIZE,
 722           "l1-cache-size",
 723           "The size of L1 cache",
 724           64, 0, 0)
 725
 726 /* The size of L1 cache line in bytes.  */
 727
 728 DEFPARAM (PARAM_L1_CACHE_LINE_SIZE,
 729           "l1-cache-line-size",
 730           "The size of L1 cache line",
 731           32, 0, 0)
 732
 733 /* The size of L2 cache in kB.  */
 734
 735 DEFPARAM (PARAM_L2_CACHE_SIZE,
 736           "l2-cache-size",
 737           "The size of L2 cache",
 738           512, 0, 0)
 739
 740 /* Whether we should use canonical types rather than deep "structural"
 741    type checking.  Setting this value to 1 (the default) improves
 742    compilation performance in the C++ and Objective-C++ front end;
 743    this value should only be set to zero to work around bugs in the
 744    canonical type system by disabling it.  */
 745
 746 DEFPARAM (PARAM_USE_CANONICAL_TYPES,
 747           "use-canonical-types",
 748           "Whether to use canonical types",
 749           1, 0, 1)
 750
 751 DEFPARAM (PARAM_MAX_PARTIAL_ANTIC_LENGTH,
 752           "max-partial-antic-length",
 753           "Maximum length of partial antic set when performing tree pre optimization",
 754           100, 0, 0)
 755
 756 /* The following is used as a stop-gap limit for cases where really huge
 757    SCCs blow up memory and compile-time use too much.  If we hit this limit,
 758    SCCVN and such FRE and PRE will be not done at all for the current
 759    function.  */
 760
 761 DEFPARAM (PARAM_SCCVN_MAX_SCC_SIZE,
 762           "sccvn-max-scc-size",
 763           "Maximum size of a SCC before SCCVN stops processing a function",
 764           10000, 10, 0)
 765
 766 DEFPARAM (PARAM_IRA_MAX_LOOPS_NUM,
 767           "ira-max-loops-num",
 768           "Max loops number for regional RA",
 769           100, 0, 0)
 770
 771 DEFPARAM (PARAM_IRA_MAX_CONFLICT_TABLE_SIZE,
 772           "ira-max-conflict-table-size",
 773           "Max size of conflict table in MB",
 774           1000, 0, 0)
 775
 776 DEFPARAM (PARAM_IRA_LOOP_RESERVED_REGS,
 777           "ira-loop-reserved-regs",
 778           "The number of registers in each class kept unused by loop invariant motion",
 779           2, 0, 0)
 780
 781 /* Switch initialization conversion will refuse to create arrays that are
 782    bigger than this parameter times the number of switch branches.  */
 783
 784 DEFPARAM (PARAM_SWITCH_CONVERSION_BRANCH_RATIO,
 785           "switch-conversion-max-branch-ratio",
 786           "The maximum ratio between array size and switch branches for "
 787           "a switch conversion to take place",
 788           8, 1, 0)
 789
 790 /* Size of tiles when doing loop blocking.  */
 791
 792 DEFPARAM (PARAM_LOOP_BLOCK_TILE_SIZE,
 793           "loop-block-tile-size",
 794           "size of tiles for loop blocking",
 795           51, 0, 0)
 796
 797 /* Maximal number of parameters that we allow in a SCoP.  */
 798
 799 DEFPARAM (PARAM_GRAPHITE_MAX_NB_SCOP_PARAMS,
 800           "graphite-max-nb-scop-params",
 801           "maximum number of parameters in a SCoP",
 802           10, 0, 0)
 803
 804 /* Maximal number of basic blocks in the functions analyzed by Graphite.  */
 805
 806 DEFPARAM (PARAM_GRAPHITE_MAX_BBS_PER_FUNCTION,
 807           "graphite-max-bbs-per-function",
 808           "maximum number of basic blocks per function to be analyzed by Graphite",
 809           100, 0, 0)
 810
 811 /* Avoid doing loop invariant motion on very large loops.  */
 812
 813 DEFPARAM (PARAM_LOOP_INVARIANT_MAX_BBS_IN_LOOP,
 814           "loop-invariant-max-bbs-in-loop",
 815           "Max basic blocks number in loop for loop invariant motion",
 816           10000, 0, 0)
 817
 818 /* Avoid SLP vectorization of large basic blocks.  */
 819 DEFPARAM (PARAM_SLP_MAX_INSNS_IN_BB,
 820           "slp-max-insns-in-bb",
 821           "Maximum number of instructions in basic block to be considered for SLP vectorization",
 822           1000, 0, 0)
 823
 824 DEFPARAM (PARAM_MIN_INSN_TO_PREFETCH_RATIO,
 825           "min-insn-to-prefetch-ratio",
 826           "Min. ratio of insns to prefetches to enable prefetching for "
 827           "a loop with an unknown trip count",
 828           10, 0, 0)
 829
 830 DEFPARAM (PARAM_PREFETCH_MIN_INSN_TO_MEM_RATIO,
 831           "prefetch-min-insn-to-mem-ratio",
 832           "Min. ratio of insns to mem ops to enable prefetching in a loop",
 833           3, 0, 0)
 834
 835 /* Set maximum hash table size for var tracking.  */
 836
 837 DEFPARAM (PARAM_MAX_VARTRACK_SIZE,
 838           "max-vartrack-size",
 839           "Max. size of var tracking hash tables",
 840           50000000, 0, 0)
 841
 842 /* Set maximum recursion depth for var tracking expression expansion
 843    and resolution.  */
 844
 845 DEFPARAM (PARAM_MAX_VARTRACK_EXPR_DEPTH,
 846           "max-vartrack-expr-depth",
 847           "Max. recursion depth for expanding var tracking expressions",
 848           10, 0, 0)
 849
 850 /* Set minimum insn uid for non-debug insns.  */
 851
 852 DEFPARAM (PARAM_MIN_NONDEBUG_INSN_UID,
 853           "min-nondebug-insn-uid",
 854           "The minimum UID to be used for a nondebug insn",
 855           0, 1, 0)
 856
 857 DEFPARAM (PARAM_IPA_SRA_PTR_GROWTH_FACTOR,
 858           "ipa-sra-ptr-growth-factor",
 859           "Maximum allowed growth of size of new parameters ipa-sra replaces "
 860           "a pointer to an aggregate with",
 861           2, 0, 0)
 862
 863 DEFPARAM (PARAM_DEVIRT_TYPE_LIST_SIZE,
 864           "devirt-type-list-size",
 865           "Maximum size of a type list associated with each parameter for "
 866           "devirtualization",
 867           8, 0, 0)
 868
 869 /* WHOPR partitioning configuration.  */
 870
 871 DEFPARAM (PARAM_LTO_PARTITIONS,
 872           "lto-partitions",
 873           "Number of partitions the program should be split to",
 874           32, 1, 0)
 875
 876 DEFPARAM (MIN_PARTITION_SIZE,
 877           "lto-min-partition",
 878           "Minimal size of a partition for LTO (in estimated instructions)",
 879           1000, 0, 0)
 880
 881 /* Diagnostic parameters.  */
 882
 883 DEFPARAM (CXX_MAX_NAMESPACES_FOR_DIAGNOSTIC_HELP,
 884           "cxx-max-namespaces-for-diagnostic-help",
 885           "Maximum number of namespaces to search for alternatives when "
 886           "name lookup fails",
 887           1000, 0, 0)
 888
 889 /* Maximum number of conditional store pairs that can be sunk.  */
 890 DEFPARAM (PARAM_MAX_STORES_TO_SINK,
 891           "max-stores-to-sink",
 892           "Maximum number of conditional store pairs that can be sunk",
 893           2, 0, 0)
 894
 895
 896 /*
 897 Local variables:
 898 mode:c
 899 End:
 900 */