gcc/params.def

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