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          10, 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 DEFPARAM(PARAM_SMS_DFA_HISTORY,
 338          "sms-dfa-history",
 339          "The number of cycles the swing modulo scheduler considers when checking conflicts using DFA",
 340          0, 0, 0)
 341 DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD,
 342          "sms-loop-average-count-threshold",
 343          "A threshold on the average loop count considered by the swing modulo scheduler",
 344          0, 0, 0)
 345
 346 DEFPARAM(HOT_BB_COUNT_FRACTION,
 347          "hot-bb-count-fraction",
 348          "Select fraction of the maximal count of repetitions of basic block in program given basic block needs to have to be considered hot",
 349          10000, 0, 0)
 350 DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
 351          "hot-bb-frequency-fraction",
 352          "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot",
 353          1000, 0, 0)
 354
 355 DEFPARAM (PARAM_ALIGN_THRESHOLD,
 356           "align-threshold",
 357           "Select fraction of the maximal frequency of executions of basic block in function given basic block get alignment",
 358           100, 0, 0)
 359
 360 DEFPARAM (PARAM_ALIGN_LOOP_ITERATIONS,
 361           "align-loop-iterations",
 362           "Loops iterating at least selected number of iterations will get loop alignement.",
 363           4, 0, 0)
 364
 365 /* For guessed profiles, the loops having unknown number of iterations
 366    are predicted to iterate relatively few (10) times at average.
 367    For functions containing one loop with large known number of iterations
 368    and other loops having unbounded loops we would end up predicting all
 369    the other loops cold that is not usually the case.  So we need to artificially
 370    flatten the profile.
 371
 372    We need to cut the maximal predicted iterations to large enough iterations
 373    so the loop appears important, but safely within HOT_BB_COUNT_FRACTION
 374    range.  */
 375
 376 DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS,
 377          "max-predicted-iterations",
 378          "The maximum number of loop iterations we predict statically",
 379          100, 0, 0)
 380 DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
 381          "tracer-dynamic-coverage-feedback",
 382          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available",
 383          95, 0, 100)
 384 DEFPARAM(TRACER_DYNAMIC_COVERAGE,
 385          "tracer-dynamic-coverage",
 386          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available",
 387          75, 0, 100)
 388 DEFPARAM(TRACER_MAX_CODE_GROWTH,
 389          "tracer-max-code-growth",
 390          "Maximal code growth caused by tail duplication (in percent)",
 391          100, 0, 0)
 392 DEFPARAM(TRACER_MIN_BRANCH_RATIO,
 393          "tracer-min-branch-ratio",
 394          "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent)",
 395          10, 0, 100)
 396 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
 397          "tracer-min-branch-probability-feedback",
 398          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available",
 399          80, 0, 100)
 400 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
 401          "tracer-min-branch-probability",
 402          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available",
 403          50, 0, 100)
 404
 405 /* The maximum number of incoming edges to consider for crossjumping.  */
 406 DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
 407          "max-crossjump-edges",
 408          "The maximum number of incoming edges to consider for crossjumping",
 409          100, 0, 0)
 410
 411 /* The minimum number of matching instructions to consider for crossjumping.  */
 412 DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS,
 413      "min-crossjump-insns",
 414      "The minimum number of matching instructions to consider for crossjumping",
 415      5, 0, 0)
 416
 417 /* The maximum number expansion factor when copying basic blocks.  */
 418 DEFPARAM(PARAM_MAX_GROW_COPY_BB_INSNS,
 419      "max-grow-copy-bb-insns",
 420      "The maximum expansion factor when copying basic blocks",
 421      8, 0, 0)
 422
 423 /* The maximum number of insns to duplicate when unfactoring computed gotos.  */
 424 DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS,
 425      "max-goto-duplication-insns",
 426      "The maximum number of insns to duplicate when unfactoring computed gotos",
 427      8, 0, 0)
 428
 429 /* The maximum length of path considered in cse.  */
 430 DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
 431          "max-cse-path-length",
 432          "The maximum length of path considered in cse",
 433          10, 0, 0)
 434 DEFPARAM(PARAM_MAX_CSE_INSNS,
 435          "max-cse-insns",
 436          "The maximum instructions CSE process before flushing",
 437          1000, 0, 0)
 438
 439 /* The cost of expression in loop invariant motion that is considered
 440    expensive.  */
 441 DEFPARAM(PARAM_LIM_EXPENSIVE,
 442          "lim-expensive",
 443          "The minimum cost of an expensive expression in the loop invariant motion",
 444          20, 0, 0)
 445
 446 /* Bound on number of candidates for induction variables below that
 447    all candidates are considered for each use in induction variable
 448    optimizations.  */
 449
 450 DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND,
 451          "iv-consider-all-candidates-bound",
 452          "Bound on number of candidates below that all candidates are considered in iv optimizations",
 453          30, 0, 0)
 454
 455 /* The induction variable optimizations give up on loops that contain more
 456    induction variable uses.  */
 457
 458 DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES,
 459          "iv-max-considered-uses",
 460          "Bound on number of iv uses in loop optimized in iv optimizations",
 461          250, 0, 0)
 462
 463 /* If there are at most this number of ivs in the set, try removing unnecessary
 464    ivs from the set always.  */
 465
 466 DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND,
 467          "iv-always-prune-cand-set-bound",
 468          "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization",
 469          10, 0, 0)
 470
 471 DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE,
 472          "scev-max-expr-size",
 473          "Bound on size of expressions used in the scalar evolutions analyzer",
 474          100, 0, 0)
 475
 476 DEFPARAM(PARAM_SCEV_MAX_EXPR_COMPLEXITY,
 477          "scev-max-expr-complexity",
 478          "Bound on the complexity of the expressions in the scalar evolutions analyzer",
 479          10, 0, 0)
 480
 481 DEFPARAM(PARAM_OMEGA_MAX_VARS,
 482          "omega-max-vars",
 483          "Bound on the number of variables in Omega constraint systems",
 484          128, 0, 0)
 485
 486 DEFPARAM(PARAM_OMEGA_MAX_GEQS,
 487          "omega-max-geqs",
 488          "Bound on the number of inequalities in Omega constraint systems",
 489          256, 0, 0)
 490
 491 DEFPARAM(PARAM_OMEGA_MAX_EQS,
 492          "omega-max-eqs",
 493          "Bound on the number of equalities in Omega constraint systems",
 494          128, 0, 0)
 495
 496 DEFPARAM(PARAM_OMEGA_MAX_WILD_CARDS,
 497          "omega-max-wild-cards",
 498          "Bound on the number of wild cards in Omega constraint systems",
 499          18, 0, 0)
 500
 501 DEFPARAM(PARAM_OMEGA_HASH_TABLE_SIZE,
 502          "omega-hash-table-size",
 503          "Bound on the size of the hash table in Omega constraint systems",
 504          550, 0, 0)
 505
 506 DEFPARAM(PARAM_OMEGA_MAX_KEYS,
 507          "omega-max-keys",
 508          "Bound on the number of keys in Omega constraint systems",
 509          500, 0, 0)
 510
 511 DEFPARAM(PARAM_OMEGA_ELIMINATE_REDUNDANT_CONSTRAINTS,
 512          "omega-eliminate-redundant-constraints",
 513          "When set to 1, use expensive methods to eliminate all redundant constraints",
 514          0, 0, 1)
 515
 516 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIGNMENT_CHECKS,
 517          "vect-max-version-for-alignment-checks",
 518          "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alignment check",
 519          6, 0, 0)
 520
 521 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS,
 522          "vect-max-version-for-alias-checks",
 523          "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alias check",
 524          10, 0, 0)
 525
 526 DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS,
 527          "max-cselib-memory-locations",
 528          "The maximum memory locations recorded by cselib",
 529          500, 0, 0)
 530
 531 #ifdef ENABLE_GC_ALWAYS_COLLECT
 532 # define GGC_MIN_EXPAND_DEFAULT 0
 533 # define GGC_MIN_HEAPSIZE_DEFAULT 0
 534 #else
 535 # define GGC_MIN_EXPAND_DEFAULT 30
 536 # define GGC_MIN_HEAPSIZE_DEFAULT 4096
 537 #endif
 538
 539 DEFPARAM(GGC_MIN_EXPAND,
 540          "ggc-min-expand",
 541          "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap",
 542          GGC_MIN_EXPAND_DEFAULT, 0, 0)
 543
 544 DEFPARAM(GGC_MIN_HEAPSIZE,
 545          "ggc-min-heapsize",
 546          "Minimum heap size before we start collecting garbage, in kilobytes",
 547          GGC_MIN_HEAPSIZE_DEFAULT, 0, 0)
 548
 549 #undef GGC_MIN_EXPAND_DEFAULT
 550 #undef GGC_MIN_HEAPSIZE_DEFAULT
 551
 552 DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
 553          "max-reload-search-insns",
 554          "The maximum number of instructions to search backward when looking for equivalent reload",
 555          100, 0, 0)
 556
 557 DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS,
 558          "max-sched-region-blocks",
 559          "The maximum number of blocks in a region to be considered for interblock scheduling",
 560          10, 0, 0)
 561
 562 DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS,
 563          "max-sched-region-insns",
 564          "The maximum number of insns in a region to be considered for interblock scheduling",
 565          100, 0, 0)
 566
 567 DEFPARAM(PARAM_MAX_PIPELINE_REGION_BLOCKS,
 568          "max-pipeline-region-blocks",
 569          "The maximum number of blocks in a region to be considered for interblock scheduling",
 570          15, 0, 0)
 571
 572 DEFPARAM(PARAM_MAX_PIPELINE_REGION_INSNS,
 573          "max-pipeline-region-insns",
 574          "The maximum number of insns in a region to be considered for interblock scheduling",
 575          200, 0, 0)
 576
 577 DEFPARAM(PARAM_MIN_SPEC_PROB,
 578          "min-spec-prob",
 579          "The minimum probability of reaching a source block for interblock speculative scheduling",
 580          40, 0, 0)
 581
 582 DEFPARAM(PARAM_MAX_SCHED_EXTEND_REGIONS_ITERS,
 583          "max-sched-extend-regions-iters",
 584          "The maximum number of iterations through CFG to extend regions",
 585          0, 0, 0)
 586
 587 DEFPARAM(PARAM_MAX_SCHED_INSN_CONFLICT_DELAY,
 588          "max-sched-insn-conflict-delay",
 589          "The maximum conflict delay for an insn to be considered for speculative motion",
 590          3, 1, 10)
 591
 592 DEFPARAM(PARAM_SCHED_SPEC_PROB_CUTOFF,
 593          "sched-spec-prob-cutoff",
 594          "The minimal probability of speculation success (in percents), so that speculative insn will be scheduled.",
 595          40, 0, 100)
 596
 597 DEFPARAM(PARAM_SELSCHED_MAX_LOOKAHEAD,
 598          "selsched-max-lookahead",
 599          "The maximum size of the lookahead window of selective scheduling",
 600          50, 0, 0)
 601
 602 DEFPARAM(PARAM_SELSCHED_MAX_SCHED_TIMES,
 603          "selsched-max-sched-times",
 604          "Maximum number of times that an insn could be scheduled",
 605          2, 0, 0)
 606
 607 DEFPARAM(PARAM_SELSCHED_INSNS_TO_RENAME,
 608          "selsched-insns-to-rename",
 609          "Maximum number of instructions in the ready list that are considered eligible for renaming",
 610          2, 0, 0)
 611
 612 DEFPARAM (PARAM_SCHED_MEM_TRUE_DEP_COST,
 613           "sched-mem-true-dep-cost",
 614           "Minimal distance between possibly conflicting store and load",
 615           1, 0, 0)
 616
 617 DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
 618          "max-last-value-rtl",
 619          "The maximum number of RTL nodes that can be recorded as combiner's last value",
 620          10000, 0, 0)
 621
 622 /* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
 623    {signed,unsigned} integral types.  This determines N.
 624    Experimentation shows 256 to be a good value.  */
 625 DEFPARAM (PARAM_INTEGER_SHARE_LIMIT,
 626           "integer-share-limit",
 627           "The upper bound for sharing integer constants",
 628           256, 2, 2)
 629
 630 /* Incremental SSA updates for virtual operands may be very slow if
 631    there is a large number of mappings to process.  In those cases, it
 632    is faster to rewrite the virtual symbols from scratch as if they
 633    had been recently introduced.  This heuristic cannot be applied to
 634    SSA mappings for real SSA names, only symbols kept in FUD chains.
 635
 636    PARAM_MIN_VIRTUAL_MAPPINGS specifies the minimum number of virtual
 637    mappings that should be registered to trigger the heuristic.
 638
 639    PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO specifies the ratio between
 640    mappings and symbols.  If the number of virtual mappings is
 641    PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO bigger than the number of
 642    virtual symbols to be updated, then the updater switches to a full
 643    update for those symbols.  */
 644 DEFPARAM (PARAM_MIN_VIRTUAL_MAPPINGS,
 645           "min-virtual-mappings",
 646           "Minimum number of virtual mappings to consider switching to full virtual renames",
 647           100, 0, 0)
 648
 649 DEFPARAM (PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO,
 650           "virtual-mappings-ratio",
 651           "Ratio between virtual mappings and virtual symbols to do full virtual renames",
 652           3, 0, 0)
 653
 654 DEFPARAM (PARAM_SSP_BUFFER_SIZE,
 655           "ssp-buffer-size",
 656           "The lower bound for a buffer to be considered for stack smashing protection",
 657           8, 1, 0)
 658
 659 /* When we thread through a block we have to make copies of the
 660    statements within the block.  Clearly for large blocks the code
 661    duplication is bad.
 662
 663    PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number
 664    of statements and PHI nodes allowed in a block which is going to
 665    be duplicated for thread jumping purposes.
 666
 667    Some simple analysis showed that more than 99% of the jump
 668    threading opportunities are for blocks with less than 15
 669    statements.  So we can get the benefits of jump threading
 670    without excessive code bloat for pathological cases with the
 671    throttle set at 15 statements.  */
 672 DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS,
 673           "max-jump-thread-duplication-stmts",
 674           "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps",
 675           15, 0, 0)
 676
 677 /* This is the maximum number of fields a variable may have before the pointer analysis machinery
 678    will stop trying to treat it in a field-sensitive manner.
 679    There are programs out there with thousands of fields per structure, and handling them
 680    field-sensitively is not worth the cost.  */
 681 DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE,
 682           "max-fields-for-field-sensitive",
 683           "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable",
 684           0, 0, 0)
 685
 686 DEFPARAM(PARAM_MAX_SCHED_READY_INSNS,
 687          "max-sched-ready-insns",
 688          "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass",
 689          100, 0, 0)
 690
 691 /* This is the maximum number of active local stores RTL DSE will consider.  */
 692 DEFPARAM (PARAM_MAX_DSE_ACTIVE_LOCAL_STORES,
 693           "max-dse-active-local-stores",
 694           "Maximum number of active local stores in RTL dead store elimination",
 695           5000, 0, 0)
 696
 697 /* Prefetching and cache-optimizations related parameters.  Default values are
 698    usually set by machine description.  */
 699
 700 /* The number of insns executed before prefetch is completed.  */
 701
 702 DEFPARAM (PARAM_PREFETCH_LATENCY,
 703          "prefetch-latency",
 704          "The number of insns executed before prefetch is completed",
 705          200, 0, 0)
 706
 707 /* The number of prefetches that can run at the same time.  */
 708
 709 DEFPARAM (PARAM_SIMULTANEOUS_PREFETCHES,
 710           "simultaneous-prefetches",
 711           "The number of prefetches that can run at the same time",
 712           3, 0, 0)
 713
 714 /* The size of L1 cache in kB.  */
 715
 716 DEFPARAM (PARAM_L1_CACHE_SIZE,
 717           "l1-cache-size",
 718           "The size of L1 cache",
 719           64, 0, 0)
 720
 721 /* The size of L1 cache line in bytes.  */
 722
 723 DEFPARAM (PARAM_L1_CACHE_LINE_SIZE,
 724           "l1-cache-line-size",
 725           "The size of L1 cache line",
 726           32, 0, 0)
 727
 728 /* The size of L2 cache in kB.  */
 729
 730 DEFPARAM (PARAM_L2_CACHE_SIZE,
 731           "l2-cache-size",
 732           "The size of L2 cache",
 733           512, 0, 0)
 734
 735 /* Whether we should use canonical types rather than deep "structural"
 736    type checking.  Setting this value to 1 (the default) improves
 737    compilation performance in the C++ and Objective-C++ front end;
 738    this value should only be set to zero to work around bugs in the
 739    canonical type system by disabling it.  */
 740
 741 DEFPARAM (PARAM_USE_CANONICAL_TYPES,
 742           "use-canonical-types",
 743           "Whether to use canonical types",
 744           1, 0, 1)
 745
 746 DEFPARAM (PARAM_MAX_PARTIAL_ANTIC_LENGTH,
 747           "max-partial-antic-length",
 748           "Maximum length of partial antic set when performing tree pre optimization",
 749           100, 0, 0)
 750
 751 /* The following is used as a stop-gap limit for cases where really huge
 752    SCCs blow up memory and compile-time use too much.  If we hit this limit,
 753    SCCVN and such FRE and PRE will be not done at all for the current
 754    function.  */
 755
 756 DEFPARAM (PARAM_SCCVN_MAX_SCC_SIZE,
 757           "sccvn-max-scc-size",
 758           "Maximum size of a SCC before SCCVN stops processing a function",
 759           10000, 10, 0)
 760
 761 DEFPARAM (PARAM_IRA_MAX_LOOPS_NUM,
 762           "ira-max-loops-num",
 763           "Max loops number for regional RA",
 764           100, 0, 0)
 765
 766 DEFPARAM (PARAM_IRA_MAX_CONFLICT_TABLE_SIZE,
 767           "ira-max-conflict-table-size",
 768           "Max size of conflict table in MB",
 769           1000, 0, 0)
 770
 771 DEFPARAM (PARAM_IRA_LOOP_RESERVED_REGS,
 772           "ira-loop-reserved-regs",
 773           "The number of registers in each class kept unused by loop invariant motion",
 774           2, 0, 0)
 775
 776 /* Switch initialization conversion will refuse to create arrays that are
 777    bigger than this parameter times the number of switch branches.  */
 778
 779 DEFPARAM (PARAM_SWITCH_CONVERSION_BRANCH_RATIO,
 780           "switch-conversion-max-branch-ratio",
 781           "The maximum ratio between array size and switch branches for "
 782           "a switch conversion to take place",
 783           8, 1, 0)
 784
 785 /* Size of tiles when doing loop blocking.  */
 786
 787 DEFPARAM (PARAM_LOOP_BLOCK_TILE_SIZE,
 788           "loop-block-tile-size",
 789           "size of tiles for loop blocking",
 790           51, 0, 0)
 791
 792 /* Maximal number of parameters that we allow in a SCoP.  */
 793
 794 DEFPARAM (PARAM_GRAPHITE_MAX_NB_SCOP_PARAMS,
 795           "graphite-max-nb-scop-params",
 796           "maximum number of parameters in a SCoP",
 797           10, 0, 0)
 798
 799 /* Maximal number of basic blocks in the functions analyzed by Graphite.  */
 800
 801 DEFPARAM (PARAM_GRAPHITE_MAX_BBS_PER_FUNCTION,
 802           "graphite-max-bbs-per-function",
 803           "maximum number of basic blocks per function to be analyzed by Graphite",
 804           100, 0, 0)
 805
 806 /* Avoid doing loop invariant motion on very large loops.  */
 807
 808 DEFPARAM (PARAM_LOOP_INVARIANT_MAX_BBS_IN_LOOP,
 809           "loop-invariant-max-bbs-in-loop",
 810           "Max basic blocks number in loop for loop invariant motion",
 811           10000, 0, 0)
 812
 813 /* Avoid SLP vectorization of large basic blocks.  */
 814 DEFPARAM (PARAM_SLP_MAX_INSNS_IN_BB,
 815           "slp-max-insns-in-bb",
 816           "Maximum number of instructions in basic block to be considered for SLP vectorization",
 817           1000, 0, 0)
 818
 819 DEFPARAM (PARAM_MIN_INSN_TO_PREFETCH_RATIO,
 820           "min-insn-to-prefetch-ratio",
 821           "Min. ratio of insns to prefetches to enable prefetching for "
 822           "a loop with an unknown trip count",
 823           10, 0, 0)
 824
 825 DEFPARAM (PARAM_PREFETCH_MIN_INSN_TO_MEM_RATIO,
 826           "prefetch-min-insn-to-mem-ratio",
 827           "Min. ratio of insns to mem ops to enable prefetching in a loop",
 828           3, 0, 0)
 829
 830 /* Set maximum hash table size for var tracking.  */
 831
 832 DEFPARAM (PARAM_MAX_VARTRACK_SIZE,
 833           "max-vartrack-size",
 834           "Max. size of var tracking hash tables",
 835           50000000, 0, 0)
 836
 837 /* Set minimum insn uid for non-debug insns.  */
 838
 839 DEFPARAM (PARAM_MIN_NONDEBUG_INSN_UID,
 840           "min-nondebug-insn-uid",
 841           "The minimum UID to be used for a nondebug insn",
 842           0, 1, 0)
 843
 844 DEFPARAM (PARAM_IPA_SRA_PTR_GROWTH_FACTOR,
 845           "ipa-sra-ptr-growth-factor",
 846           "Maximum allowed growth of size of new parameters ipa-sra replaces "
 847           "a pointer to an aggregate with",
 848           2, 0, 0)
 849
 850 DEFPARAM (PARAM_DEVIRT_TYPE_LIST_SIZE,
 851           "devirt-type-list-size",
 852           "Maximum size of a type list associated with each parameter for "
 853           "devirtualization",
 854           8, 0, 0)
 855
 856 /* WHOPR partitioning configuration.  */
 857
 858 DEFPARAM (PARAM_LTO_PARTITIONS,
 859           "lto-partitions",
 860           "Number of partitions the program should be split to",
 861           32, 1, 0)
 862
 863 DEFPARAM (MIN_PARTITION_SIZE,
 864           "lto-min-partition",
 865           "Minimal size of a partition for LTO (in estimated instructions)",
 866           1000, 0, 0)
 867
 868 /* Diagnostic parameters.  */
 869
 870 DEFPARAM (CXX_MAX_NAMESPACES_FOR_DIAGNOSTIC_HELP,
 871           "cxx-max-namespaces-for-diagnostic-help",
 872           "Maximum number of namespaces to search for alternatives when "
 873           "name lookup fails",
 874           1000, 0, 0)
 875
 876 /* Maximum number of conditional store pairs that can be sunk.  */
 877 DEFPARAM (PARAM_MAX_STORES_TO_SINK,
 878           "max-stores-to-sink",
 879           "Maximum number of conditional store pairs that can be sunk",
 880           2, 0, 0)
 881
 882
 883 /*
 884 Local variables:
 885 mode:c
 886 End:
 887 */