gcc/params.def

   1 /* params.def - Run-time parameters.
   2    Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
   3    2011, 2012
   4    Free Software Foundation, Inc.
   5    Written by Mark Mitchell <mark@codesourcery.com>.
   6
   7 This file is part of GCC.
   8
   9 GCC is free software; you can redistribute it and/or modify it under
  10 the terms of the GNU General Public License as published by the Free
  11 Software Foundation; either version 3, or (at your option) any later
  12 version.
  13
  14 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  15 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  16 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  17 for more details.
  18
  19 You should have received a copy of the GNU General Public License
  20 along with GCC; see the file COPYING3.  If not see
  21 <http://www.gnu.org/licenses/>.  */
  22
  23 /* This file contains definitions for language-independent
  24    parameters.  The DEFPARAM macro takes 6 arguments:
  25
  26      - The enumeral corresponding to this parameter.
  27
  28      - The name that can be used to set this parameter using the
  29        command-line option `--param <name>=<value>'.
  30
  31      - A help string explaining how the parameter is used.
  32
  33      - A default value for the parameter.
  34
  35      - The minimum acceptable value for the parameter.
  36
  37      - The maximum acceptable value for the parameter (if greater than
  38      the minimum).
  39
  40    Be sure to add an entry to invoke.texi summarizing the parameter.  */
  41
  42 /* When branch is predicted to be taken with probability lower than this
  43    threshold (in percent), then it is considered well predictable. */
  44 DEFPARAM (PARAM_PREDICTABLE_BRANCH_OUTCOME,
  45           "predictable-branch-outcome",
  46           "Maximal estimated outcome of branch considered predictable",
  47           2, 0, 50)
  48
  49 DEFPARAM (PARAM_INLINE_MIN_SPEEDUP,
  50           "inline-min-speedup",
  51           "The minimal estimated speedup allowing inliner to ignore inline-insns-single and inline-isnsns-auto",
  52           10, 0, 0)
  53
  54 /* The single function inlining limit. This is the maximum size
  55    of a function counted in internal gcc instructions (not in
  56    real machine instructions) that is eligible for inlining
  57    by the tree inliner.
  58    The default value is 450.
  59    Only functions marked inline (or methods defined in the class
  60    definition for C++) are affected by this.
  61    There are more restrictions to inlining: If inlined functions
  62    call other functions, the already inlined instructions are
  63    counted and once the recursive inline limit (see
  64    "max-inline-insns" parameter) is exceeded, the acceptable size
  65    gets decreased.  */
  66 DEFPARAM (PARAM_MAX_INLINE_INSNS_SINGLE,
  67           "max-inline-insns-single",
  68           "The maximum number of instructions in a single function eligible for inlining",
  69           400, 0, 0)
  70
  71 /* The single function inlining limit for functions that are
  72    inlined by virtue of -finline-functions (-O3).
  73    This limit should be chosen to be below or equal to the limit
  74    that is applied to functions marked inlined (or defined in the
  75    class declaration in C++) given by the "max-inline-insns-single"
  76    parameter.
  77    The default value is 40.  */
  78 DEFPARAM (PARAM_MAX_INLINE_INSNS_AUTO,
  79           "max-inline-insns-auto",
  80           "The maximum number of instructions when automatically inlining",
  81           40, 0, 0)
  82
  83 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE,
  84           "max-inline-insns-recursive",
  85           "The maximum number of instructions inline function can grow to via recursive inlining",
  86           450, 0, 0)
  87
  88 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO,
  89           "max-inline-insns-recursive-auto",
  90           "The maximum number of instructions non-inline function can grow to via recursive inlining",
  91           450, 0, 0)
  92
  93 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH,
  94           "max-inline-recursive-depth",
  95           "The maximum depth of recursive inlining for inline functions",
  96           8, 0, 0)
  97
  98 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO,
  99           "max-inline-recursive-depth-auto",
 100           "The maximum depth of recursive inlining for non-inline functions",
 101           8, 0, 0)
 102
 103 DEFPARAM (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY,
 104           "min-inline-recursive-probability",
 105           "Inline recursively only when the probability of call being executed exceeds the parameter",
 106           10, 0, 0)
 107
 108 /* Limit of iterations of early inliner.  This basically bounds number of
 109    nested indirect calls early inliner can resolve.  Deeper chains are still
 110    handled by late inlining.  */
 111 DEFPARAM (PARAM_EARLY_INLINER_MAX_ITERATIONS,
 112           "max-early-inliner-iterations",
 113           "The maximum number of nested indirect inlining performed by early inliner",
 114           10, 0, 0)
 115
 116 /* Limit on probability of entry BB.  */
 117 DEFPARAM (PARAM_COMDAT_SHARING_PROBABILITY,
 118           "comdat-sharing-probability",
 119           "Probability that COMDAT function will be shared with different compilation unit",
 120           20, 0, 0)
 121
 122 /* Limit on probability of entry BB.  */
 123 DEFPARAM (PARAM_PARTIAL_INLINING_ENTRY_PROBABILITY,
 124           "partial-inlining-entry-probability",
 125           "Maximum probability of the entry BB of split region (in percent relative to entry BB of the function) to make partial inlining happen",
 126           70, 0, 0)
 127
 128 /* Limit the number of expansions created by the variable expansion
 129    optimization to avoid register pressure.  */
 130 DEFPARAM (PARAM_MAX_VARIABLE_EXPANSIONS,
 131           "max-variable-expansions-in-unroller",
 132           "If -fvariable-expansion-in-unroller is used, the maximum number of times that an individual variable will be expanded during loop unrolling",
 133           1, 0, 0)
 134
 135 /* Limit loop autovectorization to loops with large enough iteration count.  */
 136 DEFPARAM (PARAM_MIN_VECT_LOOP_BOUND,
 137           "min-vect-loop-bound",
 138           "If -ftree-vectorize is used, the minimal loop bound of a loop to be considered for vectorization",
 139           1, 1, 0)
 140
 141 /* The maximum number of instructions to consider when looking for an
 142    instruction to fill a delay slot.  If more than this arbitrary
 143    number of instructions is searched, the time savings from filling
 144    the delay slot will be minimal so stop searching.  Increasing
 145    values mean more aggressive optimization, making the compile time
 146    increase with probably small improvement in executable run time.  */
 147 DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH,
 148           "max-delay-slot-insn-search",
 149           "The maximum number of instructions to consider to fill a delay slot",
 150           100, 0, 0)
 151
 152 /* When trying to fill delay slots, the maximum number of instructions
 153    to consider when searching for a block with valid live register
 154    information.  Increasing this arbitrarily chosen value means more
 155    aggressive optimization, increasing the compile time.  This
 156    parameter should be removed when the delay slot code is rewritten
 157    to maintain the control-flow graph.  */
 158 DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH,
 159          "max-delay-slot-live-search",
 160          "The maximum number of instructions to consider to find accurate live register information",
 161          333, 0, 0)
 162
 163 /* This parameter limits the number of branch elements that the
 164    scheduler will track anti-dependencies through without resetting
 165    the tracking mechanism.  Large functions with few calls or barriers
 166    can generate lists containing many 1000's of dependencies.  Generally
 167    the compiler either uses all available memory, or runs for far too long.  */
 168 DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH,
 169          "max-pending-list-length",
 170          "The maximum length of scheduling's pending operations list",
 171          32, 0, 0)
 172
 173 /* This parameter limits the number of backtracking attempts when using the
 174    haifa scheduler for modulo scheduling.  */
 175 DEFPARAM(PARAM_MAX_MODULO_BACKTRACK_ATTEMPTS,
 176          "max-modulo-backtrack-attempts",
 177          "The maximum number of backtrack attempts the scheduler should make when modulo scheduling a loop",
 178          40, 0, 0)
 179
 180 DEFPARAM(PARAM_LARGE_FUNCTION_INSNS,
 181          "large-function-insns",
 182          "The size of function body to be considered large",
 183          2700, 0, 0)
 184 DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH,
 185          "large-function-growth",
 186          "Maximal growth due to inlining of large function (in percent)",
 187          100, 0, 0)
 188 DEFPARAM(PARAM_LARGE_UNIT_INSNS,
 189          "large-unit-insns",
 190          "The size of translation unit to be considered large",
 191          10000, 0, 0)
 192 DEFPARAM(PARAM_INLINE_UNIT_GROWTH,
 193          "inline-unit-growth",
 194          "How much can given compilation unit grow because of the inlining (in percent)",
 195          30, 0, 0)
 196 DEFPARAM(PARAM_IPCP_UNIT_GROWTH,
 197          "ipcp-unit-growth",
 198          "How much can given compilation unit grow because of the interprocedural constant propagation (in percent)",
 199          10, 0, 0)
 200 DEFPARAM(PARAM_EARLY_INLINING_INSNS,
 201          "early-inlining-insns",
 202          "Maximal estimated growth of function body caused by early inlining of single call",
 203          11, 0, 0)
 204 DEFPARAM(PARAM_LARGE_STACK_FRAME,
 205          "large-stack-frame",
 206          "The size of stack frame to be considered large",
 207          256, 0, 0)
 208 DEFPARAM(PARAM_STACK_FRAME_GROWTH,
 209          "large-stack-frame-growth",
 210          "Maximal stack frame growth due to inlining (in percent)",
 211          1000, 0, 0)
 212
 213 /* The GCSE optimization will be disabled if it would require
 214    significantly more memory than this value.  */
 215 DEFPARAM(PARAM_MAX_GCSE_MEMORY,
 216          "max-gcse-memory",
 217          "The maximum amount of memory to be allocated by GCSE",
 218          50 * 1024 * 1024, 0, 0)
 219
 220 /* The GCSE optimization of an expression will avoided if the ratio of
 221    insertions to deletions is greater than this value.  */
 222 DEFPARAM(PARAM_MAX_GCSE_INSERTION_RATIO,
 223          "max-gcse-insertion-ratio",
 224          "The maximum ratio of insertions to deletions of expressions in GCSE",
 225          20, 0, 0)
 226
 227 /* This is the threshold ratio when to perform partial redundancy
 228    elimination after reload. We perform partial redundancy elimination
 229    when the following holds:
 230    (Redundant load execution count)
 231    ------------------------------- >= GCSE_AFTER_RELOAD_PARTIAL_FRACTION
 232    (Added loads execution count)                                          */
 233 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_PARTIAL_FRACTION,
 234         "gcse-after-reload-partial-fraction",
 235         "The threshold ratio for performing partial redundancy elimination after reload",
 236         3, 0, 0)
 237 /* This is the threshold ratio of the critical edges execution count compared to
 238    the redundant loads execution count that permits performing the load
 239    redundancy elimination in gcse after reload.  */
 240 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_CRITICAL_FRACTION,
 241         "gcse-after-reload-critical-fraction",
 242         "The threshold ratio of critical edges execution count that permit performing redundancy elimination after reload",
 243         10, 0, 0)
 244
 245 /* GCSE will use GCSE_COST_DISTANCE_RATION as a scaling factor
 246    to calculate maximum distance for which an expression is allowed to move
 247    from its rtx_cost.  */
 248 DEFPARAM(PARAM_GCSE_COST_DISTANCE_RATIO,
 249          "gcse-cost-distance-ratio",
 250          "Scaling factor in calculation of maximum distance an expression can be moved by GCSE optimizations",
 251          10, 0, 0)
 252 /* GCSE won't restrict distance for which an expression with rtx_cost greater
 253    than COSTS_N_INSN(GCSE_UNRESTRICTED_COST) is allowed to move.  */
 254 DEFPARAM(PARAM_GCSE_UNRESTRICTED_COST,
 255          "gcse-unrestricted-cost",
 256          "Cost at which GCSE optimizations will not constraint the distance an expression can travel",
 257          3, 0, 0)
 258
 259 /* How deep from a given basic block the dominator tree should be searched
 260    for expressions to hoist to the block.  The value of 0 will avoid limiting
 261    the search.  */
 262 DEFPARAM(PARAM_MAX_HOIST_DEPTH,
 263          "max-hoist-depth",
 264          "Maximum depth of search in the dominator tree for expressions to hoist",
 265          30, 0, 0)
 266
 267 /* This parameter limits the number of insns in a loop that will be unrolled,
 268    and by how much the loop is unrolled.
 269
 270    This limit should be at most half of the peeling limits:  loop unroller
 271    decides to not unroll loops that iterate fewer than 2*number of allowed
 272    unrollings and thus we would have loops that are neither peeled or unrolled
 273    otherwise.  */
 274 DEFPARAM(PARAM_MAX_UNROLLED_INSNS,
 275          "max-unrolled-insns",
 276          "The maximum number of instructions to consider to unroll in a loop",
 277          200, 0, 0)
 278 /* This parameter limits how many times the loop is unrolled depending
 279    on number of insns really executed in each iteration.  */
 280 DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS,
 281          "max-average-unrolled-insns",
 282          "The maximum number of instructions to consider to unroll in a loop on average",
 283          80, 0, 0)
 284 /* The maximum number of unrollings of a single loop.  */
 285 DEFPARAM(PARAM_MAX_UNROLL_TIMES,
 286         "max-unroll-times",
 287         "The maximum number of unrollings of a single loop",
 288         8, 0, 0)
 289 /* The maximum number of insns of a peeled loop.  */
 290 DEFPARAM(PARAM_MAX_PEELED_INSNS,
 291         "max-peeled-insns",
 292         "The maximum number of insns of a peeled loop",
 293         100, 0, 0)
 294 /* The maximum number of peelings of a single loop.  */
 295 DEFPARAM(PARAM_MAX_PEEL_TIMES,
 296         "max-peel-times",
 297         "The maximum number of peelings of a single loop",
 298         16, 0, 0)
 299 /* The maximum number of peelings of a single loop that is peeled completely.  */
 300 DEFPARAM(PARAM_MAX_PEEL_BRANCHES,
 301         "max-peel-branches",
 302         "The maximum number of branches on the path through the peeled sequence",
 303         32, 0, 0)
 304 /* The maximum number of insns of a peeled loop.  */
 305 DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS,
 306         "max-completely-peeled-insns",
 307         "The maximum number of insns of a completely peeled loop",
 308         100, 0, 0)
 309 /* The maximum number of peelings of a single loop that is peeled completely.  */
 310 DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES,
 311         "max-completely-peel-times",
 312         "The maximum number of peelings of a single loop that is peeled completely",
 313         16, 0, 0)
 314 /* The maximum number of insns of a peeled loop that rolls only once.  */
 315 DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS,
 316         "max-once-peeled-insns",
 317         "The maximum number of insns of a peeled loop that rolls only once",
 318         400, 0, 0)
 319 /* The maximum depth of a loop nest we completely peel.  */
 320 DEFPARAM(PARAM_MAX_UNROLL_ITERATIONS,
 321          "max-completely-peel-loop-nest-depth",
 322          "The maximum depth of a loop nest we completely peel",
 323          8, 0, 0)
 324
 325 /* The maximum number of insns of an unswitched loop.  */
 326 DEFPARAM(PARAM_MAX_UNSWITCH_INSNS,
 327         "max-unswitch-insns",
 328         "The maximum number of insns of an unswitched loop",
 329         50, 0, 0)
 330 /* The maximum level of recursion in unswitch_single_loop.  */
 331 DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL,
 332         "max-unswitch-level",
 333         "The maximum number of unswitchings in a single loop",
 334         3, 0, 0)
 335
 336 /* The maximum number of iterations of a loop the brute force algorithm
 337    for analysis of # of iterations of the loop tries to evaluate.  */
 338 DEFPARAM(PARAM_MAX_ITERATIONS_TO_TRACK,
 339         "max-iterations-to-track",
 340         "Bound on the number of iterations the brute force # of iterations analysis algorithm evaluates",
 341         1000, 0, 0)
 342 /* A cutoff to avoid costly computations of the number of iterations in
 343    the doloop transformation.  */
 344 DEFPARAM(PARAM_MAX_ITERATIONS_COMPUTATION_COST,
 345         "max-iterations-computation-cost",
 346         "Bound on the cost of an expression to compute the number of iterations",
 347         10, 0, 0)
 348
 349 /* This parameter is used to tune SMS MAX II calculations.  */
 350 DEFPARAM(PARAM_SMS_MAX_II_FACTOR,
 351          "sms-max-ii-factor",
 352          "A factor for tuning the upper bound that swing modulo scheduler uses for scheduling a loop",
 353          100, 0, 0)
 354 /* The minimum value of stage count that swing modulo scheduler will generate.  */
 355 DEFPARAM(PARAM_SMS_MIN_SC,
 356         "sms-min-sc",
 357         "The minimum value of stage count that swing modulo scheduler will generate.",
 358         2, 1, 1)
 359 DEFPARAM(PARAM_SMS_DFA_HISTORY,
 360          "sms-dfa-history",
 361          "The number of cycles the swing modulo scheduler considers when checking conflicts using DFA",
 362          0, 0, 0)
 363 DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD,
 364          "sms-loop-average-count-threshold",
 365          "A threshold on the average loop count considered by the swing modulo scheduler",
 366          0, 0, 0)
 367
 368 DEFPARAM(HOT_BB_COUNT_FRACTION,
 369          "hot-bb-count-fraction",
 370          "Select fraction of the maximal count of repetitions of basic block in program given basic block needs to have to be considered hot",
 371          10000, 0, 0)
 372 DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
 373          "hot-bb-frequency-fraction",
 374          "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot",
 375          1000, 0, 0)
 376
 377 DEFPARAM (PARAM_ALIGN_THRESHOLD,
 378           "align-threshold",
 379           "Select fraction of the maximal frequency of executions of basic block in function given basic block get alignment",
 380           100, 0, 0)
 381
 382 DEFPARAM (PARAM_ALIGN_LOOP_ITERATIONS,
 383           "align-loop-iterations",
 384           "Loops iterating at least selected number of iterations will get loop alignement.",
 385           4, 0, 0)
 386
 387 /* For guessed profiles, the loops having unknown number of iterations
 388    are predicted to iterate relatively few (10) times at average.
 389    For functions containing one loop with large known number of iterations
 390    and other loops having unbounded loops we would end up predicting all
 391    the other loops cold that is not usually the case.  So we need to artificially
 392    flatten the profile.
 393
 394    We need to cut the maximal predicted iterations to large enough iterations
 395    so the loop appears important, but safely within HOT_BB_COUNT_FRACTION
 396    range.  */
 397
 398 DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS,
 399          "max-predicted-iterations",
 400          "The maximum number of loop iterations we predict statically",
 401          100, 0, 0)
 402 DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
 403          "tracer-dynamic-coverage-feedback",
 404          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available",
 405          95, 0, 100)
 406 DEFPARAM(TRACER_DYNAMIC_COVERAGE,
 407          "tracer-dynamic-coverage",
 408          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available",
 409          75, 0, 100)
 410 DEFPARAM(TRACER_MAX_CODE_GROWTH,
 411          "tracer-max-code-growth",
 412          "Maximal code growth caused by tail duplication (in percent)",
 413          100, 0, 0)
 414 DEFPARAM(TRACER_MIN_BRANCH_RATIO,
 415          "tracer-min-branch-ratio",
 416          "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent)",
 417          10, 0, 100)
 418 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
 419          "tracer-min-branch-probability-feedback",
 420          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available",
 421          80, 0, 100)
 422 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
 423          "tracer-min-branch-probability",
 424          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available",
 425          50, 0, 100)
 426
 427 /* The maximum number of incoming edges to consider for crossjumping.  */
 428 DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
 429          "max-crossjump-edges",
 430          "The maximum number of incoming edges to consider for crossjumping",
 431          100, 0, 0)
 432
 433 /* The minimum number of matching instructions to consider for crossjumping.  */
 434 DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS,
 435      "min-crossjump-insns",
 436      "The minimum number of matching instructions to consider for crossjumping",
 437      5, 0, 0)
 438
 439 /* The maximum number expansion factor when copying basic blocks.  */
 440 DEFPARAM(PARAM_MAX_GROW_COPY_BB_INSNS,
 441      "max-grow-copy-bb-insns",
 442      "The maximum expansion factor when copying basic blocks",
 443      8, 0, 0)
 444
 445 /* The maximum number of insns to duplicate when unfactoring computed gotos.  */
 446 DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS,
 447      "max-goto-duplication-insns",
 448      "The maximum number of insns to duplicate when unfactoring computed gotos",
 449      8, 0, 0)
 450
 451 /* The maximum length of path considered in cse.  */
 452 DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
 453          "max-cse-path-length",
 454          "The maximum length of path considered in cse",
 455          10, 0, 0)
 456 DEFPARAM(PARAM_MAX_CSE_INSNS,
 457          "max-cse-insns",
 458          "The maximum instructions CSE process before flushing",
 459          1000, 0, 0)
 460
 461 /* The cost of expression in loop invariant motion that is considered
 462    expensive.  */
 463 DEFPARAM(PARAM_LIM_EXPENSIVE,
 464          "lim-expensive",
 465          "The minimum cost of an expensive expression in the loop invariant motion",
 466          20, 0, 0)
 467
 468 /* Bound on number of candidates for induction variables below that
 469    all candidates are considered for each use in induction variable
 470    optimizations.  */
 471
 472 DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND,
 473          "iv-consider-all-candidates-bound",
 474          "Bound on number of candidates below that all candidates are considered in iv optimizations",
 475          30, 0, 0)
 476
 477 /* The induction variable optimizations give up on loops that contain more
 478    induction variable uses.  */
 479
 480 DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES,
 481          "iv-max-considered-uses",
 482          "Bound on number of iv uses in loop optimized in iv optimizations",
 483          250, 0, 0)
 484
 485 /* If there are at most this number of ivs in the set, try removing unnecessary
 486    ivs from the set always.  */
 487
 488 DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND,
 489          "iv-always-prune-cand-set-bound",
 490          "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization",
 491          10, 0, 0)
 492
 493 DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE,
 494          "scev-max-expr-size",
 495          "Bound on size of expressions used in the scalar evolutions analyzer",
 496          100, 0, 0)
 497
 498 DEFPARAM(PARAM_SCEV_MAX_EXPR_COMPLEXITY,
 499          "scev-max-expr-complexity",
 500          "Bound on the complexity of the expressions in the scalar evolutions analyzer",
 501          10, 0, 0)
 502
 503 DEFPARAM(PARAM_OMEGA_MAX_VARS,
 504          "omega-max-vars",
 505          "Bound on the number of variables in Omega constraint systems",
 506          128, 0, 0)
 507
 508 DEFPARAM(PARAM_OMEGA_MAX_GEQS,
 509          "omega-max-geqs",
 510          "Bound on the number of inequalities in Omega constraint systems",
 511          256, 0, 0)
 512
 513 DEFPARAM(PARAM_OMEGA_MAX_EQS,
 514          "omega-max-eqs",
 515          "Bound on the number of equalities in Omega constraint systems",
 516          128, 0, 0)
 517
 518 DEFPARAM(PARAM_OMEGA_MAX_WILD_CARDS,
 519          "omega-max-wild-cards",
 520          "Bound on the number of wild cards in Omega constraint systems",
 521          18, 0, 0)
 522
 523 DEFPARAM(PARAM_OMEGA_HASH_TABLE_SIZE,
 524          "omega-hash-table-size",
 525          "Bound on the size of the hash table in Omega constraint systems",
 526          550, 0, 0)
 527
 528 DEFPARAM(PARAM_OMEGA_MAX_KEYS,
 529          "omega-max-keys",
 530          "Bound on the number of keys in Omega constraint systems",
 531          500, 0, 0)
 532
 533 DEFPARAM(PARAM_OMEGA_ELIMINATE_REDUNDANT_CONSTRAINTS,
 534          "omega-eliminate-redundant-constraints",
 535          "When set to 1, use expensive methods to eliminate all redundant constraints",
 536          0, 0, 1)
 537
 538 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIGNMENT_CHECKS,
 539          "vect-max-version-for-alignment-checks",
 540          "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alignment check",
 541          6, 0, 0)
 542
 543 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS,
 544          "vect-max-version-for-alias-checks",
 545          "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alias check",
 546          10, 0, 0)
 547
 548 DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS,
 549          "max-cselib-memory-locations",
 550          "The maximum memory locations recorded by cselib",
 551          500, 0, 0)
 552
 553 #ifdef ENABLE_GC_ALWAYS_COLLECT
 554 # define GGC_MIN_EXPAND_DEFAULT 0
 555 # define GGC_MIN_HEAPSIZE_DEFAULT 0
 556 #else
 557 # define GGC_MIN_EXPAND_DEFAULT 30
 558 # define GGC_MIN_HEAPSIZE_DEFAULT 4096
 559 #endif
 560
 561 DEFPARAM(GGC_MIN_EXPAND,
 562          "ggc-min-expand",
 563          "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap",
 564          GGC_MIN_EXPAND_DEFAULT, 0, 0)
 565
 566 DEFPARAM(GGC_MIN_HEAPSIZE,
 567          "ggc-min-heapsize",
 568          "Minimum heap size before we start collecting garbage, in kilobytes",
 569          GGC_MIN_HEAPSIZE_DEFAULT, 0, 0)
 570
 571 #undef GGC_MIN_EXPAND_DEFAULT
 572 #undef GGC_MIN_HEAPSIZE_DEFAULT
 573
 574 DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
 575          "max-reload-search-insns",
 576          "The maximum number of instructions to search backward when looking for equivalent reload",
 577          100, 0, 0)
 578
 579 DEFPARAM(PARAM_SINK_FREQUENCY_THRESHOLD,
 580          "sink-frequency-threshold",
 581          "Target block's relative execution frequency (as a percentage) required to sink a statement",
 582          75, 0, 100)
 583
 584 DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS,
 585          "max-sched-region-blocks",
 586          "The maximum number of blocks in a region to be considered for interblock scheduling",
 587          10, 0, 0)
 588
 589 DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS,
 590          "max-sched-region-insns",
 591          "The maximum number of insns in a region to be considered for interblock scheduling",
 592          100, 0, 0)
 593
 594 DEFPARAM(PARAM_MAX_PIPELINE_REGION_BLOCKS,
 595          "max-pipeline-region-blocks",
 596          "The maximum number of blocks in a region to be considered for interblock scheduling",
 597          15, 0, 0)
 598
 599 DEFPARAM(PARAM_MAX_PIPELINE_REGION_INSNS,
 600          "max-pipeline-region-insns",
 601          "The maximum number of insns in a region to be considered for interblock scheduling",
 602          200, 0, 0)
 603
 604 DEFPARAM(PARAM_MIN_SPEC_PROB,
 605          "min-spec-prob",
 606          "The minimum probability of reaching a source block for interblock speculative scheduling",
 607          40, 0, 0)
 608
 609 DEFPARAM(PARAM_MAX_SCHED_EXTEND_REGIONS_ITERS,
 610          "max-sched-extend-regions-iters",
 611          "The maximum number of iterations through CFG to extend regions",
 612          0, 0, 0)
 613
 614 DEFPARAM(PARAM_MAX_SCHED_INSN_CONFLICT_DELAY,
 615          "max-sched-insn-conflict-delay",
 616          "The maximum conflict delay for an insn to be considered for speculative motion",
 617          3, 1, 10)
 618
 619 DEFPARAM(PARAM_SCHED_SPEC_PROB_CUTOFF,
 620          "sched-spec-prob-cutoff",
 621          "The minimal probability of speculation success (in percents), so that speculative insn will be scheduled.",
 622          40, 0, 100)
 623
 624 DEFPARAM(PARAM_SCHED_STATE_EDGE_PROB_CUTOFF,
 625          "sched-state-edge-prob-cutoff",
 626          "The minimum probability an edge must have for the scheduler to save its state across it.",
 627          10, 0, 100)
 628
 629 DEFPARAM(PARAM_SELSCHED_MAX_LOOKAHEAD,
 630          "selsched-max-lookahead",
 631          "The maximum size of the lookahead window of selective scheduling",
 632          50, 0, 0)
 633
 634 DEFPARAM(PARAM_SELSCHED_MAX_SCHED_TIMES,
 635          "selsched-max-sched-times",
 636          "Maximum number of times that an insn could be scheduled",
 637          2, 0, 0)
 638
 639 DEFPARAM(PARAM_SELSCHED_INSNS_TO_RENAME,
 640          "selsched-insns-to-rename",
 641          "Maximum number of instructions in the ready list that are considered eligible for renaming",
 642          2, 0, 0)
 643
 644 DEFPARAM (PARAM_SCHED_MEM_TRUE_DEP_COST,
 645           "sched-mem-true-dep-cost",
 646           "Minimal distance between possibly conflicting store and load",
 647           1, 0, 0)
 648
 649 DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
 650          "max-last-value-rtl",
 651          "The maximum number of RTL nodes that can be recorded as combiner's last value",
 652          10000, 0, 0)
 653
 654 /* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
 655    {signed,unsigned} integral types.  This determines N.
 656    Experimentation shows 251 to be a good value that generates the
 657    least amount of garbage for allocating the TREE_VEC storage.  */
 658 DEFPARAM (PARAM_INTEGER_SHARE_LIMIT,
 659           "integer-share-limit",
 660           "The upper bound for sharing integer constants",
 661           251, 2, 2)
 662
 663 DEFPARAM (PARAM_SSP_BUFFER_SIZE,
 664           "ssp-buffer-size",
 665           "The lower bound for a buffer to be considered for stack smashing protection",
 666           8, 1, 0)
 667
 668 /* When we thread through a block we have to make copies of the
 669    statements within the block.  Clearly for large blocks the code
 670    duplication is bad.
 671
 672    PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number
 673    of statements and PHI nodes allowed in a block which is going to
 674    be duplicated for thread jumping purposes.
 675
 676    Some simple analysis showed that more than 99% of the jump
 677    threading opportunities are for blocks with less than 15
 678    statements.  So we can get the benefits of jump threading
 679    without excessive code bloat for pathological cases with the
 680    throttle set at 15 statements.  */
 681 DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS,
 682           "max-jump-thread-duplication-stmts",
 683           "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps",
 684           15, 0, 0)
 685
 686 /* This is the maximum number of fields a variable may have before the pointer analysis machinery
 687    will stop trying to treat it in a field-sensitive manner.
 688    There are programs out there with thousands of fields per structure, and handling them
 689    field-sensitively is not worth the cost.  */
 690 DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE,
 691           "max-fields-for-field-sensitive",
 692           "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable",
 693           0, 0, 0)
 694
 695 DEFPARAM(PARAM_MAX_SCHED_READY_INSNS,
 696          "max-sched-ready-insns",
 697          "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass",
 698          100, 0, 0)
 699
 700 /* This is the maximum number of active local stores RTL DSE will consider.  */
 701 DEFPARAM (PARAM_MAX_DSE_ACTIVE_LOCAL_STORES,
 702           "max-dse-active-local-stores",
 703           "Maximum number of active local stores in RTL dead store elimination",
 704           5000, 0, 0)
 705
 706 /* Prefetching and cache-optimizations related parameters.  Default values are
 707    usually set by machine description.  */
 708
 709 /* The number of insns executed before prefetch is completed.  */
 710
 711 DEFPARAM (PARAM_PREFETCH_LATENCY,
 712          "prefetch-latency",
 713          "The number of insns executed before prefetch is completed",
 714          200, 0, 0)
 715
 716 /* The number of prefetches that can run at the same time.  */
 717
 718 DEFPARAM (PARAM_SIMULTANEOUS_PREFETCHES,
 719           "simultaneous-prefetches",
 720           "The number of prefetches that can run at the same time",
 721           3, 0, 0)
 722
 723 /* The size of L1 cache in kB.  */
 724
 725 DEFPARAM (PARAM_L1_CACHE_SIZE,
 726           "l1-cache-size",
 727           "The size of L1 cache",
 728           64, 0, 0)
 729
 730 /* The size of L1 cache line in bytes.  */
 731
 732 DEFPARAM (PARAM_L1_CACHE_LINE_SIZE,
 733           "l1-cache-line-size",
 734           "The size of L1 cache line",
 735           32, 0, 0)
 736
 737 /* The size of L2 cache in kB.  */
 738
 739 DEFPARAM (PARAM_L2_CACHE_SIZE,
 740           "l2-cache-size",
 741           "The size of L2 cache",
 742           512, 0, 0)
 743
 744 /* Whether we should use canonical types rather than deep "structural"
 745    type checking.  Setting this value to 1 (the default) improves
 746    compilation performance in the C++ and Objective-C++ front end;
 747    this value should only be set to zero to work around bugs in the
 748    canonical type system by disabling it.  */
 749
 750 DEFPARAM (PARAM_USE_CANONICAL_TYPES,
 751           "use-canonical-types",
 752           "Whether to use canonical types",
 753           1, 0, 1)
 754
 755 DEFPARAM (PARAM_MAX_PARTIAL_ANTIC_LENGTH,
 756           "max-partial-antic-length",
 757           "Maximum length of partial antic set when performing tree pre optimization",
 758           100, 0, 0)
 759
 760 /* The following is used as a stop-gap limit for cases where really huge
 761    SCCs blow up memory and compile-time use too much.  If we hit this limit,
 762    SCCVN and such FRE and PRE will be not done at all for the current
 763    function.  */
 764
 765 DEFPARAM (PARAM_SCCVN_MAX_SCC_SIZE,
 766           "sccvn-max-scc-size",
 767           "Maximum size of a SCC before SCCVN stops processing a function",
 768           10000, 10, 0)
 769
 770 /* The following is used as a stop-gap limit for cases where really huge
 771    functions blow up compile-time use too much.  It limits the number of
 772    alias-queries we do for finding common subexpressions for memory loads and
 773    stores.  The number of alias-queries is otherwise limited by the number of
 774    stores on paths to function entry.  */
 775
 776 DEFPARAM (PARAM_SCCVN_MAX_ALIAS_QUERIES_PER_ACCESS,
 777           "sccvn-max-alias-queries-per-access",
 778           "Maximum number of disambiguations to perform per memory access",
 779           1000, 0, 0)
 780
 781 DEFPARAM (PARAM_IRA_MAX_LOOPS_NUM,
 782           "ira-max-loops-num",
 783           "Max loops number for regional RA",
 784           100, 0, 0)
 785
 786 DEFPARAM (PARAM_IRA_MAX_CONFLICT_TABLE_SIZE,
 787           "ira-max-conflict-table-size",
 788           "Max size of conflict table in MB",
 789           1000, 0, 0)
 790
 791 DEFPARAM (PARAM_IRA_LOOP_RESERVED_REGS,
 792           "ira-loop-reserved-regs",
 793           "The number of registers in each class kept unused by loop invariant motion",
 794           2, 0, 0)
 795
 796 /* Switch initialization conversion will refuse to create arrays that are
 797    bigger than this parameter times the number of switch branches.  */
 798
 799 DEFPARAM (PARAM_SWITCH_CONVERSION_BRANCH_RATIO,
 800           "switch-conversion-max-branch-ratio",
 801           "The maximum ratio between array size and switch branches for "
 802           "a switch conversion to take place",
 803           8, 1, 0)
 804
 805 /* Size of tiles when doing loop blocking.  */
 806
 807 DEFPARAM (PARAM_LOOP_BLOCK_TILE_SIZE,
 808           "loop-block-tile-size",
 809           "size of tiles for loop blocking",
 810           51, 0, 0)
 811
 812 /* Maximal number of parameters that we allow in a SCoP.  */
 813
 814 DEFPARAM (PARAM_GRAPHITE_MAX_NB_SCOP_PARAMS,
 815           "graphite-max-nb-scop-params",
 816           "maximum number of parameters in a SCoP",
 817           10, 0, 0)
 818
 819 /* Maximal number of basic blocks in the functions analyzed by Graphite.  */
 820
 821 DEFPARAM (PARAM_GRAPHITE_MAX_BBS_PER_FUNCTION,
 822           "graphite-max-bbs-per-function",
 823           "maximum number of basic blocks per function to be analyzed by Graphite",
 824           100, 0, 0)
 825
 826 /* Avoid data dependence analysis on very large loops.  */
 827 DEFPARAM (PARAM_LOOP_MAX_DATAREFS_FOR_DATADEPS,
 828           "loop-max-datarefs-for-datadeps",
 829           "Maximum number of datarefs in loop for building loop data dependencies",
 830           1000, 0, 0)
 831
 832 /* Avoid doing loop invariant motion on very large loops.  */
 833
 834 DEFPARAM (PARAM_LOOP_INVARIANT_MAX_BBS_IN_LOOP,
 835           "loop-invariant-max-bbs-in-loop",
 836           "Max basic blocks number in loop for loop invariant motion",
 837           10000, 0, 0)
 838
 839 /* Avoid SLP vectorization of large basic blocks.  */
 840 DEFPARAM (PARAM_SLP_MAX_INSNS_IN_BB,
 841           "slp-max-insns-in-bb",
 842           "Maximum number of instructions in basic block to be considered for SLP vectorization",
 843           1000, 0, 0)
 844
 845 DEFPARAM (PARAM_MIN_INSN_TO_PREFETCH_RATIO,
 846           "min-insn-to-prefetch-ratio",
 847           "Min. ratio of insns to prefetches to enable prefetching for "
 848           "a loop with an unknown trip count",
 849           9, 0, 0)
 850
 851 DEFPARAM (PARAM_PREFETCH_MIN_INSN_TO_MEM_RATIO,
 852           "prefetch-min-insn-to-mem-ratio",
 853           "Min. ratio of insns to mem ops to enable prefetching in a loop",
 854           3, 0, 0)
 855
 856 /* Set maximum hash table size for var tracking.  */
 857
 858 DEFPARAM (PARAM_MAX_VARTRACK_SIZE,
 859           "max-vartrack-size",
 860           "Max. size of var tracking hash tables",
 861           50000000, 0, 0)
 862
 863 /* Set maximum recursion depth for var tracking expression expansion
 864    and resolution.  */
 865
 866 DEFPARAM (PARAM_MAX_VARTRACK_EXPR_DEPTH,
 867           "max-vartrack-expr-depth",
 868           "Max. recursion depth for expanding var tracking expressions",
 869           12, 0, 0)
 870
 871 /* Set minimum insn uid for non-debug insns.  */
 872
 873 DEFPARAM (PARAM_MIN_NONDEBUG_INSN_UID,
 874           "min-nondebug-insn-uid",
 875           "The minimum UID to be used for a nondebug insn",
 876           0, 1, 0)
 877
 878 DEFPARAM (PARAM_IPA_SRA_PTR_GROWTH_FACTOR,
 879           "ipa-sra-ptr-growth-factor",
 880           "Maximum allowed growth of size of new parameters ipa-sra replaces "
 881           "a pointer to an aggregate with",
 882           2, 0, 0)
 883
 884 DEFPARAM (PARAM_TM_MAX_AGGREGATE_SIZE,
 885           "tm-max-aggregate-size",
 886           "Size in bytes after which thread-local aggregates should be "
 887           "instrumented with the logging functions instead of save/restore "
 888           "pairs",
 889           9, 0, 0)
 890
 891 DEFPARAM (PARAM_IPA_CP_VALUE_LIST_SIZE,
 892           "ipa-cp-value-list-size",
 893           "Maximum size of a list of values associated with each parameter for "
 894           "interprocedural constant propagation",
 895           8, 0, 0)
 896
 897 DEFPARAM (PARAM_IPA_CP_EVAL_THRESHOLD,
 898           "ipa-cp-eval-threshold",
 899           "Threshold ipa-cp opportunity evaluation that is still considered "
 900           "beneficial to clone.",
 901           500, 0, 0)
 902
 903 DEFPARAM (PARAM_IPA_MAX_AGG_ITEMS,
 904           "ipa-max-agg-items",
 905           "Maximum number of aggregate content items for a parameter in "
 906           "jump functions and lattices",
 907           16, 0, 0)
 908
 909 DEFPARAM (PARAM_IPA_CP_LOOP_HINT_BONUS,
 910           "ipa-cp-loop-hint-bonus",
 911           "Compile-time bonus IPA-CP assigns to candidates which make loop "
 912           "bounds or strides known.",
 913           64, 0, 0)
 914
 915 /* WHOPR partitioning configuration.  */
 916
 917 DEFPARAM (PARAM_LTO_PARTITIONS,
 918           "lto-partitions",
 919           "Number of partitions the program should be split to",
 920           32, 1, 0)
 921
 922 DEFPARAM (MIN_PARTITION_SIZE,
 923           "lto-min-partition",
 924           "Minimal size of a partition for LTO (in estimated instructions)",
 925           1000, 0, 0)
 926
 927 /* Diagnostic parameters.  */
 928
 929 DEFPARAM (CXX_MAX_NAMESPACES_FOR_DIAGNOSTIC_HELP,
 930           "cxx-max-namespaces-for-diagnostic-help",
 931           "Maximum number of namespaces to search for alternatives when "
 932           "name lookup fails",
 933           1000, 0, 0)
 934
 935 /* Maximum number of conditional store pairs that can be sunk.  */
 936 DEFPARAM (PARAM_MAX_STORES_TO_SINK,
 937           "max-stores-to-sink",
 938           "Maximum number of conditional store pairs that can be sunk",
 939           2, 0, 0)
 940
 941 /* Override CASE_VALUES_THRESHOLD of when to switch from doing switch
 942    statements via if statements to using a table jump operation.  If the value
 943    is 0, the default CASE_VALUES_THRESHOLD will be used.  */
 944 DEFPARAM (PARAM_CASE_VALUES_THRESHOLD,
 945           "case-values-threshold",
 946           "The smallest number of different values for which it is best to "
 947           "use a jump-table instead of a tree of conditional branches, "
 948           "if 0, use the default for the machine",
 949           0, 0, 0)
 950
 951 /* Data race flags for C++0x memory model compliance.  */
 952 DEFPARAM (PARAM_ALLOW_LOAD_DATA_RACES,
 953           "allow-load-data-races",
 954           "Allow new data races on loads to be introduced",
 955           1, 0, 1)
 956
 957 DEFPARAM (PARAM_ALLOW_STORE_DATA_RACES,
 958           "allow-store-data-races",
 959           "Allow new data races on stores to be introduced",
 960           1, 0, 1)
 961
 962 DEFPARAM (PARAM_ALLOW_PACKED_LOAD_DATA_RACES,
 963           "allow-packed-load-data-races",
 964           "Allow new data races on packed data loads to be introduced",
 965           1, 0, 1)
 966
 967 DEFPARAM (PARAM_ALLOW_PACKED_STORE_DATA_RACES,
 968           "allow-packed-store-data-races",
 969           "Allow new data races on packed data stores to be introduced",
 970           1, 0, 1)
 971
 972 /* Reassociation width to be used by tree reassoc optimization.  */
 973 DEFPARAM (PARAM_TREE_REASSOC_WIDTH,
 974           "tree-reassoc-width",
 975           "Set the maximum number of instructions executed in parallel in "
 976           "reassociated tree. If 0, use the target dependent heuristic.",
 977           0, 0, 0)
 978
 979 DEFPARAM (PARAM_MAX_TAIL_MERGE_COMPARISONS,
 980           "max-tail-merge-comparisons",
 981           "Maximum amount of similar bbs to compare a bb with",
 982           10, 0, 0)
 983
 984 DEFPARAM (PARAM_MAX_TAIL_MERGE_ITERATIONS,
 985           "max-tail-merge-iterations",
 986           "Maximum amount of iterations of the pass over a function",
 987           2, 0, 0)
 988
 989 /* Maximum number of strings for which strlen optimization pass will
 990    track string lenths.  */
 991 DEFPARAM (PARAM_MAX_TRACKED_STRLENS,
 992           "max-tracked-strlens",
 993           "Maximum number of strings for which strlen optimization pass will "
 994           "track string lengths",
 995           1000, 0, 0)
 996
 997 /* Keep this in sync with the sched_pressure_algorithm enum.  */
 998 DEFPARAM (PARAM_SCHED_PRESSURE_ALGORITHM,
 999           "sched-pressure-algorithm",
1000           "Which -fsched-pressure algorithm to apply",
1001           1, 1, 2)
1002
1003 /* Maximum length of candidate scans in straight-line strength reduction.  */
1004 DEFPARAM (PARAM_MAX_SLSR_CANDIDATE_SCAN,
1005           "max-slsr-cand-scan",
1006           "Maximum length of candidate scans for straight-line "
1007           "strength reduction",
1008           50, 1, 999999)
1009
1010 /*
1011 Local variables:
1012 mode:c
1013 End:
1014 */