gcc/params.def

   1 /* params.def - Run-time parameters.
   2    Copyright (C) 2001, 2002, 2004, 2005 Free Software Foundation, Inc.
   3    Written by Mark Mitchell <mark@codesourcery.com>.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 /* This file contains definitions for language-independent
  22    parameters.  The DEFPARAM macro takes 6 arguments:
  23
  24      - The enumeral corresponding to this parameter.
  25
  26      - The name that can be used to set this parameter using the
  27        command-line option `--param <name>=<value>'.
  28
  29      - A help string explaining how the parameter is used.
  30
  31      - A default value for the parameter.
  32
  33      - The minimum acceptable value for the parameter.
  34
  35      - The maximum acceptable value for the parameter (if greater than
  36      the minimum).
  37
  38    Be sure to add an entry to invoke.texi summarizing the parameter.  */
  39
  40 /* The maximum number of fields in a variable with only implicit uses
  41    for which structure aliasing will consider trying to track each
  42    field.  The default is 5.  */
  43 DEFPARAM (PARAM_SALIAS_MAX_IMPLICIT_FIELDS,
  44           "salias-max-implicit-fields",
  45           "The maximum number of fields in a structure variable without direct structure accesses that GCC will attempt to track separately",
  46           5, 0, 0)
  47
  48 /* The maximum number of array elements structure aliasing will decompose
  49    an array for.  The default is 4.  */
  50 DEFPARAM (PARAM_SALIAS_MAX_ARRAY_ELEMENTS,
  51           "salias-max-array-elements",
  52           "The maximum number of elements in an array for wich we track its elements separately",
  53           4, 0, 0)
  54
  55 /* The maximum structure size at which the scalar replacement of
  56    aggregates (SRA) pass will perform block copies.  The default
  57    value, 0, implies that GCC will select the most appropriate size
  58    itself.  */
  59 DEFPARAM (PARAM_SRA_MAX_STRUCTURE_SIZE,
  60           "sra-max-structure-size",
  61           "The maximum structure size (in bytes) for which GCC will "
  62           "use by-element copies",
  63           0, 0, 0)
  64
  65 /* The maximum number of structure fields which the SRA pass will
  66    instantiate to avoid block copies.  The default value, 0, implies
  67    that GCC will select the appropriate value itself.  */
  68 DEFPARAM (PARAM_SRA_MAX_STRUCTURE_COUNT,
  69           "sra-max-structure-count",
  70           "The maximum number of structure fields for which GCC will "
  71           "use by-element copies",
  72           0, 0, 0)
  73
  74 /* The ratio between instantiated fields and the complete structure
  75    size.  We say that if the ratio of the number of bytes in
  76    instantiated fields to the number of bytes in the complete
  77    structure exceeds this parameter, or if the number of instantiated
  78    fields to the total number of fields exceeds this parameter, then
  79    block copies are not used.  The default is 75%.  */
  80 DEFPARAM (PARAM_SRA_FIELD_STRUCTURE_RATIO,
  81           "sra-field-structure-ratio",
  82           "The threshold ratio between instantiated fields and the total structure size",
  83           75, 0, 100)
  84
  85 /* The single function inlining limit. This is the maximum size
  86    of a function counted in internal gcc instructions (not in
  87    real machine instructions) that is eligible for inlining
  88    by the tree inliner.
  89    The default value is 450.
  90    Only functions marked inline (or methods defined in the class
  91    definition for C++) are affected by this.
  92    There are more restrictions to inlining: If inlined functions
  93    call other functions, the already inlined instructions are
  94    counted and once the recursive inline limit (see
  95    "max-inline-insns" parameter) is exceeded, the acceptable size
  96    gets decreased.  */
  97 DEFPARAM (PARAM_MAX_INLINE_INSNS_SINGLE,
  98           "max-inline-insns-single",
  99           "The maximum number of instructions in a single function eligible for inlining",
 100           450, 0, 0)
 101
 102 /* The single function inlining limit for functions that are
 103    inlined by virtue of -finline-functions (-O3).
 104    This limit should be chosen to be below or equal to the limit
 105    that is applied to functions marked inlined (or defined in the
 106    class declaration in C++) given by the "max-inline-insns-single"
 107    parameter.
 108    The default value is 90.  */
 109 DEFPARAM (PARAM_MAX_INLINE_INSNS_AUTO,
 110           "max-inline-insns-auto",
 111           "The maximum number of instructions when automatically inlining",
 112           90, 0, 0)
 113
 114 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE,
 115           "max-inline-insns-recursive",
 116           "The maximum number of instructions inline function can grow to via recursive inlining",
 117           450, 0, 0)
 118
 119 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO,
 120           "max-inline-insns-recursive-auto",
 121           "The maximum number of instructions non-inline function can grow to via recursive inlining",
 122           450, 0, 0)
 123
 124 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH,
 125           "max-inline-recursive-depth",
 126           "The maximum depth of recursive inlining for inline functions",
 127           8, 0, 0)
 128
 129 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO,
 130           "max-inline-recursive-depth-auto",
 131           "The maximum depth of recursive inlining for non-inline functions",
 132           8, 0, 0)
 133
 134 DEFPARAM (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY,
 135           "min-inline-recursive-probability",
 136           "Inline recursively only when the probability of call being executed exceeds the parameter",
 137           10, 0, 0)
 138
 139 /* Limit the number of expansions created by the variable expansion
 140    optimization to avoid register pressure.  */
 141 DEFPARAM (PARAM_MAX_VARIABLE_EXPANSIONS,
 142           "max-variable-expansions-in-unroller",
 143           "If -fvariable-expansion-in-unroller is used, the maximum number of times that an individual variable will be expanded during loop unrolling",
 144           1, 0, 0)
 145
 146 /* The maximum number of instructions to consider when looking for an
 147    instruction to fill a delay slot.  If more than this arbitrary
 148    number of instructions is searched, the time savings from filling
 149    the delay slot will be minimal so stop searching.  Increasing
 150    values mean more aggressive optimization, making the compile time
 151    increase with probably small improvement in executable run time.  */
 152 DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH,
 153           "max-delay-slot-insn-search",
 154           "The maximum number of instructions to consider to fill a delay slot",
 155           100, 0, 0)
 156
 157 /* When trying to fill delay slots, the maximum number of instructions
 158    to consider when searching for a block with valid live register
 159    information.  Increasing this arbitrarily chosen value means more
 160    aggressive optimization, increasing the compile time.  This
 161    parameter should be removed when the delay slot code is rewritten
 162    to maintain the control-flow graph.  */
 163 DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH,
 164          "max-delay-slot-live-search",
 165          "The maximum number of instructions to consider to find accurate live register information",
 166          333, 0, 0)
 167
 168 /* This parameter limits the number of branch elements that the
 169    scheduler will track anti-dependencies through without resetting
 170    the tracking mechanism.  Large functions with few calls or barriers
 171    can generate lists containing many 1000's of dependencies.  Generally
 172    the compiler either uses all available memory, or runs for far too long.  */
 173 DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH,
 174          "max-pending-list-length",
 175          "The maximum length of scheduling's pending operations list",
 176          32, 0, 0)
 177
 178 DEFPARAM(PARAM_LARGE_FUNCTION_INSNS,
 179          "large-function-insns",
 180          "The size of function body to be considered large",
 181          2700, 0, 0)
 182 DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH,
 183          "large-function-growth",
 184          "Maximal growth due to inlining of large function (in percent)",
 185          100, 0, 0)
 186 DEFPARAM(PARAM_LARGE_UNIT_INSNS,
 187          "large-unit-insns",
 188          "The size of translation unit to be considered large",
 189          10000, 0, 0)
 190 DEFPARAM(PARAM_INLINE_UNIT_GROWTH,
 191          "inline-unit-growth",
 192          "how much can given compilation unit grow because of the inlining (in percent)",
 193          50, 0, 0)
 194 DEFPARAM(PARAM_INLINE_CALL_COST,
 195          "inline-call-cost",
 196          "expense of call operation relative to ordinary arithmetic operations",
 197          16, 0, 0)
 198
 199 /* The GCSE optimization will be disabled if it would require
 200    significantly more memory than this value.  */
 201 DEFPARAM(PARAM_MAX_GCSE_MEMORY,
 202          "max-gcse-memory",
 203          "The maximum amount of memory to be allocated by GCSE",
 204          50 * 1024 * 1024, 0, 0)
 205 /* The number of repetitions of copy/const prop and PRE to run.  */
 206 DEFPARAM(PARAM_MAX_GCSE_PASSES,
 207         "max-gcse-passes",
 208         "The maximum number of passes to make when doing GCSE",
 209         1, 1, 0)
 210 /* This is the threshold ratio when to perform partial redundancy
 211    elimination after reload. We perform partial redundancy elimination
 212    when the following holds:
 213    (Redundant load execution count)
 214    ------------------------------- >= GCSE_AFTER_RELOAD_PARTIAL_FRACTION
 215    (Added loads execution count)                                          */
 216 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_PARTIAL_FRACTION,
 217         "gcse-after-reload-partial-fraction",
 218         "The threshold ratio for performing partial redundancy elimination after reload",
 219         3, 0, 0)
 220 /* This is the threshold ratio of the critical edges execution count compared to
 221    the redundant loads execution count that permits performing the load
 222    redundancy elimination in gcse after reload.  */
 223 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_CRITICAL_FRACTION,
 224         "gcse-after-reload-critical-fraction",
 225         "The threshold ratio of critical edges execution count that permit performing redundancy elimination after reload",
 226         10, 0, 0)
 227 /* This parameter limits the number of insns in a loop that will be unrolled,
 228    and by how much the loop is unrolled.
 229
 230    This limit should be at most half of the peeling limits:  loop unroller
 231    decides to not unroll loops that iterate fewer than 2*number of allowed
 232    unrollings and thus we would have loops that are neither peeled or unrolled
 233    otherwise.  */
 234 DEFPARAM(PARAM_MAX_UNROLLED_INSNS,
 235          "max-unrolled-insns",
 236          "The maximum number of instructions to consider to unroll in a loop",
 237          200, 0, 0)
 238 /* This parameter limits how many times the loop is unrolled depending
 239    on number of insns really executed in each iteration.  */
 240 DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS,
 241          "max-average-unrolled-insns",
 242          "The maximum number of instructions to consider to unroll in a loop on average",
 243          80, 0, 0)
 244 /* The maximum number of unrollings of a single loop.  */
 245 DEFPARAM(PARAM_MAX_UNROLL_TIMES,
 246         "max-unroll-times",
 247         "The maximum number of unrollings of a single loop",
 248         8, 0, 0)
 249 /* The maximum number of insns of a peeled loop.  */
 250 DEFPARAM(PARAM_MAX_PEELED_INSNS,
 251         "max-peeled-insns",
 252         "The maximum number of insns of a peeled loop",
 253         400, 0, 0)
 254 /* The maximum number of peelings of a single loop.  */
 255 DEFPARAM(PARAM_MAX_PEEL_TIMES,
 256         "max-peel-times",
 257         "The maximum number of peelings of a single loop",
 258         16, 0, 0)
 259 /* The maximum number of insns of a peeled loop.  */
 260 DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS,
 261         "max-completely-peeled-insns",
 262         "The maximum number of insns of a completely peeled loop",
 263         400, 0, 0)
 264 /* The maximum number of peelings of a single loop that is peeled completely.  */
 265 DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES,
 266         "max-completely-peel-times",
 267         "The maximum number of peelings of a single loop that is peeled completely",
 268         16, 0, 0)
 269 /* The maximum number of insns of a peeled loop that rolls only once.  */
 270 DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS,
 271         "max-once-peeled-insns",
 272         "The maximum number of insns of a peeled loop that rolls only once",
 273         400, 0, 0)
 274
 275 /* The maximum number of insns of an unswitched loop.  */
 276 DEFPARAM(PARAM_MAX_UNSWITCH_INSNS,
 277         "max-unswitch-insns",
 278         "The maximum number of insns of an unswitched loop",
 279         50, 0, 0)
 280 /* The maximum level of recursion in unswitch_single_loop.  */
 281 DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL,
 282         "max-unswitch-level",
 283         "The maximum number of unswitchings in a single loop",
 284         3, 0, 0)
 285
 286 /* The maximum number of iterations of a loop the brute force algorithm
 287    for analysis of # of iterations of the loop tries to evaluate.  */
 288 DEFPARAM(PARAM_MAX_ITERATIONS_TO_TRACK,
 289         "max-iterations-to-track",
 290         "Bound on the number of iterations the brute force # of iterations analysis algorithm evaluates",
 291         1000, 0, 0)
 292 /* A cutoff to avoid costly computations of the number of iterations in
 293    the doloop transformation.  */
 294 DEFPARAM(PARAM_MAX_ITERATIONS_COMPUTATION_COST,
 295         "max-iterations-computation-cost",
 296         "Bound on the cost of an expression to compute the number of iterations",
 297         10, 0, 0)
 298
 299 DEFPARAM(PARAM_MAX_SMS_LOOP_NUMBER,
 300          "max-sms-loop-number",
 301          "Maximum number of loops to perform swing modulo scheduling on (mainly for debugging)",
 302          -1, -1, -1)
 303
 304 /* This parameter is used to tune SMS MAX II calculations.  */
 305 DEFPARAM(PARAM_SMS_MAX_II_FACTOR,
 306          "sms-max-ii-factor",
 307          "A factor for tuning the upper bound that swing modulo scheduler uses for scheduling a loop",
 308          100, 0, 0)
 309 DEFPARAM(PARAM_SMS_DFA_HISTORY,
 310          "sms-dfa-history",
 311          "The number of cycles the swing modulo scheduler considers when checking conflicts using DFA",
 312          0, 0, 0)
 313 DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD,
 314          "sms-loop-average-count-threshold",
 315          "A threshold on the average loop count considered by the swing modulo scheduler",
 316          0, 0, 0)
 317
 318 DEFPARAM(HOT_BB_COUNT_FRACTION,
 319          "hot-bb-count-fraction",
 320          "Select fraction of the maximal count of repetitions of basic block in program given basic block needs to have to be considered hot",
 321          10000, 0, 0)
 322 DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
 323          "hot-bb-frequency-fraction",
 324          "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot",
 325          1000, 0, 0)
 326
 327 /* For guessed profiles, the loops having unknown number of iterations
 328    are predicted to iterate relatively few (10) times at average.
 329    For functions containing one loop with large known number of iterations
 330    and other loops having unbounded loops we would end up predicting all
 331    the other loops cold that is not usually the case.  So we need to artificially
 332    flatten the profile.
 333
 334    We need to cut the maximal predicted iterations to large enough iterations
 335    so the loop appears important, but safely within HOT_BB_COUNT_FRACTION
 336    range.  */
 337
 338 DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS,
 339          "max-predicted-iterations",
 340          "The maximum number of loop iterations we predict statically",
 341          100, 0, 0)
 342 DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
 343          "tracer-dynamic-coverage-feedback",
 344          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available",
 345          95, 0, 100)
 346 DEFPARAM(TRACER_DYNAMIC_COVERAGE,
 347          "tracer-dynamic-coverage",
 348          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available",
 349          75, 0, 100)
 350 DEFPARAM(TRACER_MAX_CODE_GROWTH,
 351          "tracer-max-code-growth",
 352          "Maximal code growth caused by tail duplication (in percent)",
 353          100, 0, 0)
 354 DEFPARAM(TRACER_MIN_BRANCH_RATIO,
 355          "tracer-min-branch-ratio",
 356          "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent)",
 357          10, 0, 100)
 358 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
 359          "tracer-min-branch-probability-feedback",
 360          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available",
 361          80, 0, 100)
 362 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
 363          "tracer-min-branch-probability",
 364          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available",
 365          50, 0, 100)
 366
 367 /* The maximum number of incoming edges to consider for crossjumping.  */
 368 DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
 369          "max-crossjump-edges",
 370          "The maximum number of incoming edges to consider for crossjumping",
 371          100, 0, 0)
 372
 373 /* The minimum number of matching instructions to consider for crossjumping.  */
 374 DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS,
 375      "min-crossjump-insns",
 376      "The minimum number of matching instructions to consider for crossjumping",
 377      5, 0, 0)
 378
 379 /* The maximum number expansion factor when copying basic blocks.  */
 380 DEFPARAM(PARAM_MAX_GROW_COPY_BB_INSNS,
 381      "max-grow-copy-bb-insns",
 382      "The maximum expansion factor when copying basic blocks",
 383      8, 0, 0)
 384
 385 /* The maximum number of insns to duplicate when unfactoring computed gotos.  */
 386 DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS,
 387      "max-goto-duplication-insns",
 388      "The maximum number of insns to duplicate when unfactoring computed gotos",
 389      8, 0, 0)
 390
 391 /* The maximum length of path considered in cse.  */
 392 DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
 393          "max-cse-path-length",
 394          "The maximum length of path considered in cse",
 395          10, 0, 0)
 396 DEFPARAM(PARAM_MAX_CSE_INSNS,
 397          "max-cse-insns",
 398          "The maximum instructions CSE process before flushing",
 399          1000, 0, 0)
 400
 401 /* The cost of expression in loop invariant motion that is considered
 402    expensive.  */
 403 DEFPARAM(PARAM_LIM_EXPENSIVE,
 404          "lim-expensive",
 405          "The minimum cost of an expensive expression in the loop invariant motion",
 406          20, 0, 0)
 407
 408 /* Bound on number of candidates for induction variables below that
 409    all candidates are considered for each use in induction variable
 410    optimizations.  */
 411
 412 DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND,
 413          "iv-consider-all-candidates-bound",
 414          "Bound on number of candidates below that all candidates are considered in iv optimizations",
 415          30, 0, 0)
 416
 417 /* The induction variable optimizations give up on loops that contain more
 418    induction variable uses.  */
 419
 420 DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES,
 421          "iv-max-considered-uses",
 422          "Bound on number of iv uses in loop optimized in iv optimizations",
 423          250, 0, 0)
 424
 425 /* If there are at most this number of ivs in the set, try removing unnecessary
 426    ivs from the set always.  */
 427
 428 DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND,
 429          "iv-always-prune-cand-set-bound",
 430          "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization",
 431          10, 0, 0)
 432
 433 DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE,
 434          "scev-max-expr-size",
 435          "Bound on size of expressions used in the scalar evolutions analyzer",
 436          20, 0, 0)
 437
 438 DEFPARAM(PARAM_VECT_MAX_VERSION_CHECKS,
 439          "vect-max-version-checks",
 440          "Bound on number of runtime checks inserted by the vectorizer's loop versioning",
 441          6, 0, 0)
 442
 443 /* The product of the next two is used to decide whether or not to
 444    use .GLOBAL_VAR.  See tree-dfa.c.  */
 445 DEFPARAM(PARAM_GLOBAL_VAR_THRESHOLD,
 446         "global-var-threshold",
 447         "Given N calls and V call-clobbered vars in a function.  Use .GLOBAL_VAR if NxV is larger than this limit",
 448         500000, 0, 0)
 449
 450 DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS,
 451          "max-cselib-memory-locations",
 452          "The maximum memory locations recorded by cselib",
 453          500, 0, 0)
 454 DEFPARAM(PARAM_MAX_FLOW_MEMORY_LOCATIONS,
 455          "max-flow-memory-locations",
 456          "The maximum memory locations recorded by flow",
 457          100, 0, 0)
 458
 459 #ifdef ENABLE_GC_ALWAYS_COLLECT
 460 # define GGC_MIN_EXPAND_DEFAULT 0
 461 # define GGC_MIN_HEAPSIZE_DEFAULT 0
 462 #else
 463 # define GGC_MIN_EXPAND_DEFAULT 30
 464 # define GGC_MIN_HEAPSIZE_DEFAULT 4096
 465 #endif
 466
 467 DEFPARAM(GGC_MIN_EXPAND,
 468          "ggc-min-expand",
 469          "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap",
 470          GGC_MIN_EXPAND_DEFAULT, 0, 0)
 471
 472 DEFPARAM(GGC_MIN_HEAPSIZE,
 473          "ggc-min-heapsize",
 474          "Minimum heap size before we start collecting garbage, in kilobytes",
 475          GGC_MIN_HEAPSIZE_DEFAULT, 0, 0)
 476
 477 #undef GGC_MIN_EXPAND_DEFAULT
 478 #undef GGC_MIN_HEAPSIZE_DEFAULT
 479
 480 DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
 481          "max-reload-search-insns",
 482          "The maximum number of instructions to search backward when looking for equivalent reload",
 483          100, 0, 0)
 484
 485 DEFPARAM(PARAM_MAX_ALIASED_VOPS,
 486          "max-aliased-vops",
 487          "The maximum number of virtual operands allowed to represent aliases before triggering alias grouping",
 488          500, 0, 0)
 489
 490 DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS,
 491          "max-sched-region-blocks",
 492          "The maximum number of blocks in a region to be considered for interblock scheduling",
 493          10, 0, 0)
 494
 495 DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS,
 496          "max-sched-region-insns",
 497          "The maximum number of insns in a region to be considered for interblock scheduling",
 498          100, 0, 0)
 499
 500 DEFPARAM(PARAM_MIN_SPEC_PROB,
 501          "min-spec-prob",
 502          "The minimum probability of reaching a source block for interblock speculative scheduling",
 503          40, 0, 0)
 504
 505 DEFPARAM(PARAM_MAX_SCHED_EXTEND_REGIONS_ITERS,
 506          "max-sched-extend-regions-iters",
 507          "The maximum number of iterations through CFG to extend regions",
 508          0, 0, 0)
 509
 510 DEFPARAM(PARAM_MAX_SCHED_INSN_CONFLICT_DELAY,
 511          "max-sched-insn-conflict-delay",
 512          "The maximum conflict delay for an insn to be considered for speculative motion",
 513          3, 1, 10)
 514
 515 DEFPARAM(PARAM_SCHED_SPEC_PROB_CUTOFF,
 516          "sched-spec-prob-cutoff",
 517          "The minimal probability of speculation success (in percents), so that speculative insn will be scheduled.",
 518          40, 0, 100)
 519
 520 DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
 521          "max-last-value-rtl",
 522          "The maximum number of RTL nodes that can be recorded as combiner's last value",
 523          10000, 0, 0)
 524
 525 /* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
 526    {signed,unsigned} integral types.  This determines N.
 527    Experimentation shows 256 to be a good value.  */
 528 DEFPARAM (PARAM_INTEGER_SHARE_LIMIT,
 529           "integer-share-limit",
 530           "The upper bound for sharing integer constants",
 531           256, 2, 2)
 532
 533 /* Incremental SSA updates for virtual operands may be very slow if
 534    there is a large number of mappings to process.  In those cases, it
 535    is faster to rewrite the virtual symbols from scratch as if they
 536    had been recently introduced.  This heuristic cannot be applied to
 537    SSA mappings for real SSA names, only symbols kept in FUD chains.
 538
 539    PARAM_MIN_VIRTUAL_MAPPINGS specifies the minimum number of virtual
 540    mappings that should be registered to trigger the heuristic.
 541
 542    PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO specifies the ratio between
 543    mappings and symbols.  If the number of virtual mappings is
 544    PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO bigger than the number of
 545    virtual symbols to be updated, then the updater switches to a full
 546    update for those symbols.  */
 547 DEFPARAM (PARAM_MIN_VIRTUAL_MAPPINGS,
 548           "min-virtual-mappings",
 549           "Minimum number of virtual mappings to consider switching to full virtual renames",
 550           100, 0, 0)
 551
 552 DEFPARAM (PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO,
 553           "virtual-mappings-ratio",
 554           "Ratio between virtual mappings and virtual symbols to do full virtual renames",
 555           3, 0, 0)
 556
 557 DEFPARAM (PARAM_SSP_BUFFER_SIZE,
 558           "ssp-buffer-size",
 559           "The lower bound for a buffer to be considered for stack smashing protection",
 560           8, 1, 0)
 561
 562 /* When we thread through a block we have to make copies of the
 563    statements within the block.  Clearly for large blocks the code
 564    duplication is bad.
 565
 566    PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number
 567    of statements and PHI nodes allowed in a block which is going to
 568    be duplicated for thread jumping purposes.
 569
 570    Some simple analysis showed that more than 99% of the jump
 571    threading opportunities are for blocks with less than 15
 572    statements.  So we can get the benefits of jump threading
 573    without excessive code bloat for pathological cases with the
 574    throttle set at 15 statements.  */
 575 DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS,
 576           "max-jump-thread-duplication-stmts",
 577           "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps",
 578           15, 0, 0)
 579
 580 /* This is the maximum number of fields a variable may have before the pointer analysis machinery
 581    will stop trying to treat it in a field-sensitive manner.
 582    There are programs out there with thousands of fields per structure, and handling them
 583    field-sensitively is not worth the cost.  */
 584 DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE,
 585           "max-fields-for-field-sensitive",
 586           "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable",
 587           100, 0, 0)
 588
 589 DEFPARAM(PARAM_MAX_SCHED_READY_INSNS,
 590          "max-sched-ready-insns",
 591          "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass",
 592          100, 0, 0)
 593
 594 /*
 595 Local variables:
 596 mode:c
 597 End: */