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_WS_PERMILLE,
 369          "hot-bb-count-ws-permille",
 370          "A basic block profile count is considered hot if it contributes to "
 371          "the given permillage of the entire profiled execution",
 372          999, 0, 1000)
 373 DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
 374          "hot-bb-frequency-fraction",
 375          "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot",
 376          1000, 0, 0)
 377
 378 DEFPARAM (PARAM_ALIGN_THRESHOLD,
 379           "align-threshold",
 380           "Select fraction of the maximal frequency of executions of basic block in function given basic block get alignment",
 381           100, 0, 0)
 382
 383 DEFPARAM (PARAM_ALIGN_LOOP_ITERATIONS,
 384           "align-loop-iterations",
 385           "Loops iterating at least selected number of iterations will get loop alignement.",
 386           4, 0, 0)
 387
 388 /* For guessed profiles, the loops having unknown number of iterations
 389    are predicted to iterate relatively few (10) times at average.
 390    For functions containing one loop with large known number of iterations
 391    and other loops having unbounded loops we would end up predicting all
 392    the other loops cold that is not usually the case.  So we need to artificially
 393    flatten the profile.
 394
 395    We need to cut the maximal predicted iterations to large enough iterations
 396    so the loop appears important, but safely within maximum hotness
 397    range.  */
 398
 399 DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS,
 400          "max-predicted-iterations",
 401          "The maximum number of loop iterations we predict statically",
 402          100, 0, 0)
 403 DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
 404          "tracer-dynamic-coverage-feedback",
 405          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available",
 406          95, 0, 100)
 407 DEFPARAM(TRACER_DYNAMIC_COVERAGE,
 408          "tracer-dynamic-coverage",
 409          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available",
 410          75, 0, 100)
 411 DEFPARAM(TRACER_MAX_CODE_GROWTH,
 412          "tracer-max-code-growth",
 413          "Maximal code growth caused by tail duplication (in percent)",
 414          100, 0, 0)
 415 DEFPARAM(TRACER_MIN_BRANCH_RATIO,
 416          "tracer-min-branch-ratio",
 417          "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent)",
 418          10, 0, 100)
 419 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
 420          "tracer-min-branch-probability-feedback",
 421          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available",
 422          80, 0, 100)
 423 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
 424          "tracer-min-branch-probability",
 425          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available",
 426          50, 0, 100)
 427
 428 /* The maximum number of incoming edges to consider for crossjumping.  */
 429 DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
 430          "max-crossjump-edges",
 431          "The maximum number of incoming edges to consider for crossjumping",
 432          100, 0, 0)
 433
 434 /* The minimum number of matching instructions to consider for crossjumping.  */
 435 DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS,
 436      "min-crossjump-insns",
 437      "The minimum number of matching instructions to consider for crossjumping",
 438      5, 0, 0)
 439
 440 /* The maximum number expansion factor when copying basic blocks.  */
 441 DEFPARAM(PARAM_MAX_GROW_COPY_BB_INSNS,
 442      "max-grow-copy-bb-insns",
 443      "The maximum expansion factor when copying basic blocks",
 444      8, 0, 0)
 445
 446 /* The maximum number of insns to duplicate when unfactoring computed gotos.  */
 447 DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS,
 448      "max-goto-duplication-insns",
 449      "The maximum number of insns to duplicate when unfactoring computed gotos",
 450      8, 0, 0)
 451
 452 /* The maximum length of path considered in cse.  */
 453 DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
 454          "max-cse-path-length",
 455          "The maximum length of path considered in cse",
 456          10, 0, 0)
 457 DEFPARAM(PARAM_MAX_CSE_INSNS,
 458          "max-cse-insns",
 459          "The maximum instructions CSE process before flushing",
 460          1000, 0, 0)
 461
 462 /* The cost of expression in loop invariant motion that is considered
 463    expensive.  */
 464 DEFPARAM(PARAM_LIM_EXPENSIVE,
 465          "lim-expensive",
 466          "The minimum cost of an expensive expression in the loop invariant motion",
 467          20, 0, 0)
 468
 469 /* Bound on number of candidates for induction variables below that
 470    all candidates are considered for each use in induction variable
 471    optimizations.  */
 472
 473 DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND,
 474          "iv-consider-all-candidates-bound",
 475          "Bound on number of candidates below that all candidates are considered in iv optimizations",
 476          30, 0, 0)
 477
 478 /* The induction variable optimizations give up on loops that contain more
 479    induction variable uses.  */
 480
 481 DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES,
 482          "iv-max-considered-uses",
 483          "Bound on number of iv uses in loop optimized in iv optimizations",
 484          250, 0, 0)
 485
 486 /* If there are at most this number of ivs in the set, try removing unnecessary
 487    ivs from the set always.  */
 488
 489 DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND,
 490          "iv-always-prune-cand-set-bound",
 491          "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization",
 492          10, 0, 0)
 493
 494 DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE,
 495          "scev-max-expr-size",
 496          "Bound on size of expressions used in the scalar evolutions analyzer",
 497          100, 0, 0)
 498
 499 DEFPARAM(PARAM_SCEV_MAX_EXPR_COMPLEXITY,
 500          "scev-max-expr-complexity",
 501          "Bound on the complexity of the expressions in the scalar evolutions analyzer",
 502          10, 0, 0)
 503
 504 DEFPARAM(PARAM_OMEGA_MAX_VARS,
 505          "omega-max-vars",
 506          "Bound on the number of variables in Omega constraint systems",
 507          128, 0, 0)
 508
 509 DEFPARAM(PARAM_OMEGA_MAX_GEQS,
 510          "omega-max-geqs",
 511          "Bound on the number of inequalities in Omega constraint systems",
 512          256, 0, 0)
 513
 514 DEFPARAM(PARAM_OMEGA_MAX_EQS,
 515          "omega-max-eqs",
 516          "Bound on the number of equalities in Omega constraint systems",
 517          128, 0, 0)
 518
 519 DEFPARAM(PARAM_OMEGA_MAX_WILD_CARDS,
 520          "omega-max-wild-cards",
 521          "Bound on the number of wild cards in Omega constraint systems",
 522          18, 0, 0)
 523
 524 DEFPARAM(PARAM_OMEGA_HASH_TABLE_SIZE,
 525          "omega-hash-table-size",
 526          "Bound on the size of the hash table in Omega constraint systems",
 527          550, 0, 0)
 528
 529 DEFPARAM(PARAM_OMEGA_MAX_KEYS,
 530          "omega-max-keys",
 531          "Bound on the number of keys in Omega constraint systems",
 532          500, 0, 0)
 533
 534 DEFPARAM(PARAM_OMEGA_ELIMINATE_REDUNDANT_CONSTRAINTS,
 535          "omega-eliminate-redundant-constraints",
 536          "When set to 1, use expensive methods to eliminate all redundant constraints",
 537          0, 0, 1)
 538
 539 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIGNMENT_CHECKS,
 540          "vect-max-version-for-alignment-checks",
 541          "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alignment check",
 542          6, 0, 0)
 543
 544 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS,
 545          "vect-max-version-for-alias-checks",
 546          "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alias check",
 547          10, 0, 0)
 548
 549 DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS,
 550          "max-cselib-memory-locations",
 551          "The maximum memory locations recorded by cselib",
 552          500, 0, 0)
 553
 554 #ifdef ENABLE_GC_ALWAYS_COLLECT
 555 # define GGC_MIN_EXPAND_DEFAULT 0
 556 # define GGC_MIN_HEAPSIZE_DEFAULT 0
 557 #else
 558 # define GGC_MIN_EXPAND_DEFAULT 30
 559 # define GGC_MIN_HEAPSIZE_DEFAULT 4096
 560 #endif
 561
 562 DEFPARAM(GGC_MIN_EXPAND,
 563          "ggc-min-expand",
 564          "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap",
 565          GGC_MIN_EXPAND_DEFAULT, 0, 0)
 566
 567 DEFPARAM(GGC_MIN_HEAPSIZE,
 568          "ggc-min-heapsize",
 569          "Minimum heap size before we start collecting garbage, in kilobytes",
 570          GGC_MIN_HEAPSIZE_DEFAULT, 0, 0)
 571
 572 #undef GGC_MIN_EXPAND_DEFAULT
 573 #undef GGC_MIN_HEAPSIZE_DEFAULT
 574
 575 DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
 576          "max-reload-search-insns",
 577          "The maximum number of instructions to search backward when looking for equivalent reload",
 578          100, 0, 0)
 579
 580 DEFPARAM(PARAM_SINK_FREQUENCY_THRESHOLD,
 581          "sink-frequency-threshold",
 582          "Target block's relative execution frequency (as a percentage) required to sink a statement",
 583          75, 0, 100)
 584
 585 DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS,
 586          "max-sched-region-blocks",
 587          "The maximum number of blocks in a region to be considered for interblock scheduling",
 588          10, 0, 0)
 589
 590 DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS,
 591          "max-sched-region-insns",
 592          "The maximum number of insns in a region to be considered for interblock scheduling",
 593          100, 0, 0)
 594
 595 DEFPARAM(PARAM_MAX_PIPELINE_REGION_BLOCKS,
 596          "max-pipeline-region-blocks",
 597          "The maximum number of blocks in a region to be considered for interblock scheduling",
 598          15, 0, 0)
 599
 600 DEFPARAM(PARAM_MAX_PIPELINE_REGION_INSNS,
 601          "max-pipeline-region-insns",
 602          "The maximum number of insns in a region to be considered for interblock scheduling",
 603          200, 0, 0)
 604
 605 DEFPARAM(PARAM_MIN_SPEC_PROB,
 606          "min-spec-prob",
 607          "The minimum probability of reaching a source block for interblock speculative scheduling",
 608          40, 0, 0)
 609
 610 DEFPARAM(PARAM_MAX_SCHED_EXTEND_REGIONS_ITERS,
 611          "max-sched-extend-regions-iters",
 612          "The maximum number of iterations through CFG to extend regions",
 613          0, 0, 0)
 614
 615 DEFPARAM(PARAM_MAX_SCHED_INSN_CONFLICT_DELAY,
 616          "max-sched-insn-conflict-delay",
 617          "The maximum conflict delay for an insn to be considered for speculative motion",
 618          3, 1, 10)
 619
 620 DEFPARAM(PARAM_SCHED_SPEC_PROB_CUTOFF,
 621          "sched-spec-prob-cutoff",
 622          "The minimal probability of speculation success (in percents), so that speculative insn will be scheduled.",
 623          40, 0, 100)
 624
 625 DEFPARAM(PARAM_SCHED_STATE_EDGE_PROB_CUTOFF,
 626          "sched-state-edge-prob-cutoff",
 627          "The minimum probability an edge must have for the scheduler to save its state across it.",
 628          10, 0, 100)
 629
 630 DEFPARAM(PARAM_SELSCHED_MAX_LOOKAHEAD,
 631          "selsched-max-lookahead",
 632          "The maximum size of the lookahead window of selective scheduling",
 633          50, 0, 0)
 634
 635 DEFPARAM(PARAM_SELSCHED_MAX_SCHED_TIMES,
 636          "selsched-max-sched-times",
 637          "Maximum number of times that an insn could be scheduled",
 638          2, 0, 0)
 639
 640 DEFPARAM(PARAM_SELSCHED_INSNS_TO_RENAME,
 641          "selsched-insns-to-rename",
 642          "Maximum number of instructions in the ready list that are considered eligible for renaming",
 643          2, 0, 0)
 644
 645 DEFPARAM (PARAM_SCHED_MEM_TRUE_DEP_COST,
 646           "sched-mem-true-dep-cost",
 647           "Minimal distance between possibly conflicting store and load",
 648           1, 0, 0)
 649
 650 DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
 651          "max-last-value-rtl",
 652          "The maximum number of RTL nodes that can be recorded as combiner's last value",
 653          10000, 0, 0)
 654
 655 /* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
 656    {signed,unsigned} integral types.  This determines N.
 657    Experimentation shows 251 to be a good value that generates the
 658    least amount of garbage for allocating the TREE_VEC storage.  */
 659 DEFPARAM (PARAM_INTEGER_SHARE_LIMIT,
 660           "integer-share-limit",
 661           "The upper bound for sharing integer constants",
 662           251, 2, 2)
 663
 664 DEFPARAM (PARAM_SSP_BUFFER_SIZE,
 665           "ssp-buffer-size",
 666           "The lower bound for a buffer to be considered for stack smashing protection",
 667           8, 1, 0)
 668
 669 /* When we thread through a block we have to make copies of the
 670    statements within the block.  Clearly for large blocks the code
 671    duplication is bad.
 672
 673    PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number
 674    of statements and PHI nodes allowed in a block which is going to
 675    be duplicated for thread jumping purposes.
 676
 677    Some simple analysis showed that more than 99% of the jump
 678    threading opportunities are for blocks with less than 15
 679    statements.  So we can get the benefits of jump threading
 680    without excessive code bloat for pathological cases with the
 681    throttle set at 15 statements.  */
 682 DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS,
 683           "max-jump-thread-duplication-stmts",
 684           "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps",
 685           15, 0, 0)
 686
 687 /* This is the maximum number of fields a variable may have before the pointer analysis machinery
 688    will stop trying to treat it in a field-sensitive manner.
 689    There are programs out there with thousands of fields per structure, and handling them
 690    field-sensitively is not worth the cost.  */
 691 DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE,
 692           "max-fields-for-field-sensitive",
 693           "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable",
 694           0, 0, 0)
 695
 696 DEFPARAM(PARAM_MAX_SCHED_READY_INSNS,
 697          "max-sched-ready-insns",
 698          "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass",
 699          100, 0, 0)
 700
 701 /* This is the maximum number of active local stores RTL DSE will consider.  */
 702 DEFPARAM (PARAM_MAX_DSE_ACTIVE_LOCAL_STORES,
 703           "max-dse-active-local-stores",
 704           "Maximum number of active local stores in RTL dead store elimination",
 705           5000, 0, 0)
 706
 707 /* Prefetching and cache-optimizations related parameters.  Default values are
 708    usually set by machine description.  */
 709
 710 /* The number of insns executed before prefetch is completed.  */
 711
 712 DEFPARAM (PARAM_PREFETCH_LATENCY,
 713          "prefetch-latency",
 714          "The number of insns executed before prefetch is completed",
 715          200, 0, 0)
 716
 717 /* The number of prefetches that can run at the same time.  */
 718
 719 DEFPARAM (PARAM_SIMULTANEOUS_PREFETCHES,
 720           "simultaneous-prefetches",
 721           "The number of prefetches that can run at the same time",
 722           3, 0, 0)
 723
 724 /* The size of L1 cache in kB.  */
 725
 726 DEFPARAM (PARAM_L1_CACHE_SIZE,
 727           "l1-cache-size",
 728           "The size of L1 cache",
 729           64, 0, 0)
 730
 731 /* The size of L1 cache line in bytes.  */
 732
 733 DEFPARAM (PARAM_L1_CACHE_LINE_SIZE,
 734           "l1-cache-line-size",
 735           "The size of L1 cache line",
 736           32, 0, 0)
 737
 738 /* The size of L2 cache in kB.  */
 739
 740 DEFPARAM (PARAM_L2_CACHE_SIZE,
 741           "l2-cache-size",
 742           "The size of L2 cache",
 743           512, 0, 0)
 744
 745 /* Whether we should use canonical types rather than deep "structural"
 746    type checking.  Setting this value to 1 (the default) improves
 747    compilation performance in the C++ and Objective-C++ front end;
 748    this value should only be set to zero to work around bugs in the
 749    canonical type system by disabling it.  */
 750
 751 DEFPARAM (PARAM_USE_CANONICAL_TYPES,
 752           "use-canonical-types",
 753           "Whether to use canonical types",
 754           1, 0, 1)
 755
 756 DEFPARAM (PARAM_MAX_PARTIAL_ANTIC_LENGTH,
 757           "max-partial-antic-length",
 758           "Maximum length of partial antic set when performing tree pre optimization",
 759           100, 0, 0)
 760
 761 /* The following is used as a stop-gap limit for cases where really huge
 762    SCCs blow up memory and compile-time use too much.  If we hit this limit,
 763    SCCVN and such FRE and PRE will be not done at all for the current
 764    function.  */
 765
 766 DEFPARAM (PARAM_SCCVN_MAX_SCC_SIZE,
 767           "sccvn-max-scc-size",
 768           "Maximum size of a SCC before SCCVN stops processing a function",
 769           10000, 10, 0)
 770
 771 /* The following is used as a stop-gap limit for cases where really huge
 772    functions blow up compile-time use too much.  It limits the number of
 773    alias-queries we do for finding common subexpressions for memory loads and
 774    stores.  The number of alias-queries is otherwise limited by the number of
 775    stores on paths to function entry.  */
 776
 777 DEFPARAM (PARAM_SCCVN_MAX_ALIAS_QUERIES_PER_ACCESS,
 778           "sccvn-max-alias-queries-per-access",
 779           "Maximum number of disambiguations to perform per memory access",
 780           1000, 0, 0)
 781
 782 DEFPARAM (PARAM_IRA_MAX_LOOPS_NUM,
 783           "ira-max-loops-num",
 784           "Max loops number for regional RA",
 785           100, 0, 0)
 786
 787 DEFPARAM (PARAM_IRA_MAX_CONFLICT_TABLE_SIZE,
 788           "ira-max-conflict-table-size",
 789           "Max size of conflict table in MB",
 790           1000, 0, 0)
 791
 792 DEFPARAM (PARAM_IRA_LOOP_RESERVED_REGS,
 793           "ira-loop-reserved-regs",
 794           "The number of registers in each class kept unused by loop invariant motion",
 795           2, 0, 0)
 796
 797 /* Switch initialization conversion will refuse to create arrays that are
 798    bigger than this parameter times the number of switch branches.  */
 799
 800 DEFPARAM (PARAM_SWITCH_CONVERSION_BRANCH_RATIO,
 801           "switch-conversion-max-branch-ratio",
 802           "The maximum ratio between array size and switch branches for "
 803           "a switch conversion to take place",
 804           8, 1, 0)
 805
 806 /* Size of tiles when doing loop blocking.  */
 807
 808 DEFPARAM (PARAM_LOOP_BLOCK_TILE_SIZE,
 809           "loop-block-tile-size",
 810           "size of tiles for loop blocking",
 811           51, 0, 0)
 812
 813 /* Maximal number of parameters that we allow in a SCoP.  */
 814
 815 DEFPARAM (PARAM_GRAPHITE_MAX_NB_SCOP_PARAMS,
 816           "graphite-max-nb-scop-params",
 817           "maximum number of parameters in a SCoP",
 818           10, 0, 0)
 819
 820 /* Maximal number of basic blocks in the functions analyzed by Graphite.  */
 821
 822 DEFPARAM (PARAM_GRAPHITE_MAX_BBS_PER_FUNCTION,
 823           "graphite-max-bbs-per-function",
 824           "maximum number of basic blocks per function to be analyzed by Graphite",
 825           100, 0, 0)
 826
 827 /* Avoid data dependence analysis on very large loops.  */
 828 DEFPARAM (PARAM_LOOP_MAX_DATAREFS_FOR_DATADEPS,
 829           "loop-max-datarefs-for-datadeps",
 830           "Maximum number of datarefs in loop for building loop data dependencies",
 831           1000, 0, 0)
 832
 833 /* Avoid doing loop invariant motion on very large loops.  */
 834
 835 DEFPARAM (PARAM_LOOP_INVARIANT_MAX_BBS_IN_LOOP,
 836           "loop-invariant-max-bbs-in-loop",
 837           "Max basic blocks number in loop for loop invariant motion",
 838           10000, 0, 0)
 839
 840 /* Avoid SLP vectorization of large basic blocks.  */
 841 DEFPARAM (PARAM_SLP_MAX_INSNS_IN_BB,
 842           "slp-max-insns-in-bb",
 843           "Maximum number of instructions in basic block to be considered for SLP vectorization",
 844           1000, 0, 0)
 845
 846 DEFPARAM (PARAM_MIN_INSN_TO_PREFETCH_RATIO,
 847           "min-insn-to-prefetch-ratio",
 848           "Min. ratio of insns to prefetches to enable prefetching for "
 849           "a loop with an unknown trip count",
 850           9, 0, 0)
 851
 852 DEFPARAM (PARAM_PREFETCH_MIN_INSN_TO_MEM_RATIO,
 853           "prefetch-min-insn-to-mem-ratio",
 854           "Min. ratio of insns to mem ops to enable prefetching in a loop",
 855           3, 0, 0)
 856
 857 /* Set maximum hash table size for var tracking.  */
 858
 859 DEFPARAM (PARAM_MAX_VARTRACK_SIZE,
 860           "max-vartrack-size",
 861           "Max. size of var tracking hash tables",
 862           50000000, 0, 0)
 863
 864 /* Set maximum recursion depth for var tracking expression expansion
 865    and resolution.  */
 866
 867 DEFPARAM (PARAM_MAX_VARTRACK_EXPR_DEPTH,
 868           "max-vartrack-expr-depth",
 869           "Max. recursion depth for expanding var tracking expressions",
 870           12, 0, 0)
 871
 872 /* Set minimum insn uid for non-debug insns.  */
 873
 874 DEFPARAM (PARAM_MIN_NONDEBUG_INSN_UID,
 875           "min-nondebug-insn-uid",
 876           "The minimum UID to be used for a nondebug insn",
 877           0, 1, 0)
 878
 879 DEFPARAM (PARAM_IPA_SRA_PTR_GROWTH_FACTOR,
 880           "ipa-sra-ptr-growth-factor",
 881           "Maximum allowed growth of size of new parameters ipa-sra replaces "
 882           "a pointer to an aggregate with",
 883           2, 0, 0)
 884
 885 DEFPARAM (PARAM_TM_MAX_AGGREGATE_SIZE,
 886           "tm-max-aggregate-size",
 887           "Size in bytes after which thread-local aggregates should be "
 888           "instrumented with the logging functions instead of save/restore "
 889           "pairs",
 890           9, 0, 0)
 891
 892 DEFPARAM (PARAM_IPA_CP_VALUE_LIST_SIZE,
 893           "ipa-cp-value-list-size",
 894           "Maximum size of a list of values associated with each parameter for "
 895           "interprocedural constant propagation",
 896           8, 0, 0)
 897
 898 DEFPARAM (PARAM_IPA_CP_EVAL_THRESHOLD,
 899           "ipa-cp-eval-threshold",
 900           "Threshold ipa-cp opportunity evaluation that is still considered "
 901           "beneficial to clone.",
 902           500, 0, 0)
 903
 904 DEFPARAM (PARAM_IPA_MAX_AGG_ITEMS,
 905           "ipa-max-agg-items",
 906           "Maximum number of aggregate content items for a parameter in "
 907           "jump functions and lattices",
 908           16, 0, 0)
 909
 910 DEFPARAM (PARAM_IPA_CP_LOOP_HINT_BONUS,
 911           "ipa-cp-loop-hint-bonus",
 912           "Compile-time bonus IPA-CP assigns to candidates which make loop "
 913           "bounds or strides known.",
 914           64, 0, 0)
 915
 916 /* WHOPR partitioning configuration.  */
 917
 918 DEFPARAM (PARAM_LTO_PARTITIONS,
 919           "lto-partitions",
 920           "Number of partitions the program should be split to",
 921           32, 1, 0)
 922
 923 DEFPARAM (MIN_PARTITION_SIZE,
 924           "lto-min-partition",
 925           "Minimal size of a partition for LTO (in estimated instructions)",
 926           1000, 0, 0)
 927
 928 /* Diagnostic parameters.  */
 929
 930 DEFPARAM (CXX_MAX_NAMESPACES_FOR_DIAGNOSTIC_HELP,
 931           "cxx-max-namespaces-for-diagnostic-help",
 932           "Maximum number of namespaces to search for alternatives when "
 933           "name lookup fails",
 934           1000, 0, 0)
 935
 936 /* Maximum number of conditional store pairs that can be sunk.  */
 937 DEFPARAM (PARAM_MAX_STORES_TO_SINK,
 938           "max-stores-to-sink",
 939           "Maximum number of conditional store pairs that can be sunk",
 940           2, 0, 0)
 941
 942 /* Override CASE_VALUES_THRESHOLD of when to switch from doing switch
 943    statements via if statements to using a table jump operation.  If the value
 944    is 0, the default CASE_VALUES_THRESHOLD will be used.  */
 945 DEFPARAM (PARAM_CASE_VALUES_THRESHOLD,
 946           "case-values-threshold",
 947           "The smallest number of different values for which it is best to "
 948           "use a jump-table instead of a tree of conditional branches, "
 949           "if 0, use the default for the machine",
 950           0, 0, 0)
 951
 952 /* Data race flags for C++0x memory model compliance.  */
 953 DEFPARAM (PARAM_ALLOW_LOAD_DATA_RACES,
 954           "allow-load-data-races",
 955           "Allow new data races on loads to be introduced",
 956           1, 0, 1)
 957
 958 DEFPARAM (PARAM_ALLOW_STORE_DATA_RACES,
 959           "allow-store-data-races",
 960           "Allow new data races on stores to be introduced",
 961           1, 0, 1)
 962
 963 DEFPARAM (PARAM_ALLOW_PACKED_LOAD_DATA_RACES,
 964           "allow-packed-load-data-races",
 965           "Allow new data races on packed data loads to be introduced",
 966           1, 0, 1)
 967
 968 DEFPARAM (PARAM_ALLOW_PACKED_STORE_DATA_RACES,
 969           "allow-packed-store-data-races",
 970           "Allow new data races on packed data stores to be introduced",
 971           1, 0, 1)
 972
 973 /* Reassociation width to be used by tree reassoc optimization.  */
 974 DEFPARAM (PARAM_TREE_REASSOC_WIDTH,
 975           "tree-reassoc-width",
 976           "Set the maximum number of instructions executed in parallel in "
 977           "reassociated tree. If 0, use the target dependent heuristic.",
 978           0, 0, 0)
 979
 980 DEFPARAM (PARAM_MAX_TAIL_MERGE_COMPARISONS,
 981           "max-tail-merge-comparisons",
 982           "Maximum amount of similar bbs to compare a bb with",
 983           10, 0, 0)
 984
 985 DEFPARAM (PARAM_MAX_TAIL_MERGE_ITERATIONS,
 986           "max-tail-merge-iterations",
 987           "Maximum amount of iterations of the pass over a function",
 988           2, 0, 0)
 989
 990 /* Maximum number of strings for which strlen optimization pass will
 991    track string lenths.  */
 992 DEFPARAM (PARAM_MAX_TRACKED_STRLENS,
 993           "max-tracked-strlens",
 994           "Maximum number of strings for which strlen optimization pass will "
 995           "track string lengths",
 996           1000, 0, 0)
 997
 998 /* Keep this in sync with the sched_pressure_algorithm enum.  */
 999 DEFPARAM (PARAM_SCHED_PRESSURE_ALGORITHM,
1000           "sched-pressure-algorithm",
1001           "Which -fsched-pressure algorithm to apply",
1002           1, 1, 2)
1003
1004 /* Maximum length of candidate scans in straight-line strength reduction.  */
1005 DEFPARAM (PARAM_MAX_SLSR_CANDIDATE_SCAN,
1006           "max-slsr-cand-scan",
1007           "Maximum length of candidate scans for straight-line "
1008           "strength reduction",
1009           50, 1, 999999)
1010
1011 /*
1012 Local variables:
1013 mode:c
1014 End:
1015 */