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 2, 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 COPYING.  If not, write to the Free
  19 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  20 02110-1301, USA.
  21
  22 */
  23
  24 /* This file contains definitions for language-independent
  25    parameters.  The DEFPARAM macro takes 6 arguments:
  26
  27      - The enumeral corresponding to this parameter.
  28
  29      - The name that can be used to set this parameter using the
  30        command-line option `--param <name>=<value>'.
  31
  32      - A help string explaining how the parameter is used.
  33
  34      - A default value for the parameter.
  35
  36      - The minimum acceptable value for the parameter.
  37
  38      - The maximum acceptable value for the parameter (if greater than
  39      the minimum).
  40
  41    Be sure to add an entry to invoke.texi summarizing the parameter.  */
  42
  43 /* The maximum number of fields in a variable with only implicit uses
  44    for which structure aliasing will consider trying to track each
  45    field.  The default is 5.  */
  46 DEFPARAM (PARAM_SALIAS_MAX_IMPLICIT_FIELDS,
  47           "salias-max-implicit-fields",
  48           "The maximum number of fields in a structure variable without direct structure accesses that GCC will attempt to track separately",
  49           5, 0, 0)
  50
  51 /* The maximum number of array elements structure aliasing will decompose
  52    an array for.  The default is 4.  */
  53 DEFPARAM (PARAM_SALIAS_MAX_ARRAY_ELEMENTS,
  54           "salias-max-array-elements",
  55           "The maximum number of elements in an array for wich we track its elements separately",
  56           4, 0, 0)
  57
  58 /* The maximum structure size at which the scalar replacement of
  59    aggregates (SRA) pass will perform block copies.  The default
  60    value, 0, implies that GCC will select the most appropriate size
  61    itself.  */
  62 DEFPARAM (PARAM_SRA_MAX_STRUCTURE_SIZE,
  63           "sra-max-structure-size",
  64           "The maximum structure size (in bytes) for which GCC will "
  65           "use by-element copies",
  66           0, 0, 0)
  67
  68 /* The maximum number of structure fields which the SRA pass will
  69    instantiate to avoid block copies.  The default value, 0, implies
  70    that GCC will select the appropriate value itself.  */
  71 DEFPARAM (PARAM_SRA_MAX_STRUCTURE_COUNT,
  72           "sra-max-structure-count",
  73           "The maximum number of structure fields for which GCC will "
  74           "use by-element copies",
  75           0, 0, 0)
  76
  77 /* The ratio between instantiated fields and the complete structure
  78    size.  We say that if the ratio of the number of bytes in
  79    instantiated fields to the number of bytes in the complete
  80    structure exceeds this parameter, or if the number of instantiated
  81    fields to the total number of fields exceeds this parameter, then
  82    block copies are not used.  The default is 75%.  */
  83 DEFPARAM (PARAM_SRA_FIELD_STRUCTURE_RATIO,
  84           "sra-field-structure-ratio",
  85           "The threshold ratio between instantiated fields and the total structure size",
  86           75, 0, 100)
  87
  88 /* The single function inlining limit. This is the maximum size
  89    of a function counted in internal gcc instructions (not in
  90    real machine instructions) that is eligible for inlining
  91    by the tree inliner.
  92    The default value is 450.
  93    Only functions marked inline (or methods defined in the class
  94    definition for C++) are affected by this.
  95    There are more restrictions to inlining: If inlined functions
  96    call other functions, the already inlined instructions are
  97    counted and once the recursive inline limit (see
  98    "max-inline-insns" parameter) is exceeded, the acceptable size
  99    gets decreased.  */
 100 DEFPARAM (PARAM_MAX_INLINE_INSNS_SINGLE,
 101           "max-inline-insns-single",
 102           "The maximum number of instructions in a single function eligible for inlining",
 103           450, 0, 0)
 104
 105 /* The single function inlining limit for functions that are
 106    inlined by virtue of -finline-functions (-O3).
 107    This limit should be chosen to be below or equal to the limit
 108    that is applied to functions marked inlined (or defined in the
 109    class declaration in C++) given by the "max-inline-insns-single"
 110    parameter.
 111    The default value is 90.  */
 112 DEFPARAM (PARAM_MAX_INLINE_INSNS_AUTO,
 113           "max-inline-insns-auto",
 114           "The maximum number of instructions when automatically inlining",
 115           90, 0, 0)
 116
 117 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE,
 118           "max-inline-insns-recursive",
 119           "The maximum number of instructions inline function can grow to via recursive inlining",
 120           450, 0, 0)
 121
 122 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO,
 123           "max-inline-insns-recursive-auto",
 124           "The maximum number of instructions non-inline function can grow to via recursive inlining",
 125           450, 0, 0)
 126
 127 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH,
 128           "max-inline-recursive-depth",
 129           "The maximum depth of recursive inlining for inline functions",
 130           8, 0, 0)
 131
 132 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO,
 133           "max-inline-recursive-depth-auto",
 134           "The maximum depth of recursive inlining for non-inline functions",
 135           8, 0, 0)
 136
 137 DEFPARAM (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY,
 138           "min-inline-recursive-probability",
 139           "Inline recursively only when the probability of call being executed exceeds the parameter",
 140           10, 0, 0)
 141
 142 /* Limit the number of expansions created by the variable expansion
 143    optimization to avoid register pressure.  */
 144 DEFPARAM (PARAM_MAX_VARIABLE_EXPANSIONS,
 145           "max-variable-expansions-in-unroller",
 146           "If -fvariable-expansion-in-unroller is used, the maximum number of times that an individual variable will be expanded during loop unrolling",
 147           1, 0, 0)
 148
 149 /* The maximum number of instructions to consider when looking for an
 150    instruction to fill a delay slot.  If more than this arbitrary
 151    number of instructions is searched, the time savings from filling
 152    the delay slot will be minimal so stop searching.  Increasing
 153    values mean more aggressive optimization, making the compile time
 154    increase with probably small improvement in executable run time.  */
 155 DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH,
 156           "max-delay-slot-insn-search",
 157           "The maximum number of instructions to consider to fill a delay slot",
 158           100, 0, 0)
 159
 160 /* When trying to fill delay slots, the maximum number of instructions
 161    to consider when searching for a block with valid live register
 162    information.  Increasing this arbitrarily chosen value means more
 163    aggressive optimization, increasing the compile time.  This
 164    parameter should be removed when the delay slot code is rewritten
 165    to maintain the control-flow graph.  */
 166 DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH,
 167          "max-delay-slot-live-search",
 168          "The maximum number of instructions to consider to find accurate live register information",
 169          333, 0, 0)
 170
 171 /* This parameter limits the number of branch elements that the
 172    scheduler will track anti-dependencies through without resetting
 173    the tracking mechanism.  Large functions with few calls or barriers
 174    can generate lists containing many 1000's of dependencies.  Generally
 175    the compiler either uses all available memory, or runs for far too long.  */
 176 DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH,
 177          "max-pending-list-length",
 178          "The maximum length of scheduling's pending operations list",
 179          32, 0, 0)
 180
 181 DEFPARAM(PARAM_LARGE_FUNCTION_INSNS,
 182          "large-function-insns",
 183          "The size of function body to be considered large",
 184          2700, 0, 0)
 185 DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH,
 186          "large-function-growth",
 187          "Maximal growth due to inlining of large function (in percent)",
 188          100, 0, 0)
 189 DEFPARAM(PARAM_LARGE_UNIT_INSNS,
 190          "large-unit-insns",
 191          "The size of translation unit to be considered large",
 192          10000, 0, 0)
 193 DEFPARAM(PARAM_INLINE_UNIT_GROWTH,
 194          "inline-unit-growth",
 195          "how much can given compilation unit grow because of the inlining (in percent)",
 196          50, 0, 0)
 197 DEFPARAM(PARAM_INLINE_CALL_COST,
 198          "inline-call-cost",
 199          "expense of call operation relative to ordinary arithmetic operations",
 200          16, 0, 0)
 201 DEFPARAM(PARAM_LARGE_STACK_FRAME,
 202          "large-stack-frame",
 203          "The size of stack frame to be considered large",
 204          256, 0, 0)
 205 DEFPARAM(PARAM_STACK_FRAME_GROWTH,
 206          "large-stack-frame-growth",
 207          "Maximal stack frame growth due to inlining (in percent)",
 208          1000, 0, 0)
 209
 210 /* The GCSE optimization will be disabled if it would require
 211    significantly more memory than this value.  */
 212 DEFPARAM(PARAM_MAX_GCSE_MEMORY,
 213          "max-gcse-memory",
 214          "The maximum amount of memory to be allocated by GCSE",
 215          50 * 1024 * 1024, 0, 0)
 216 /* The number of repetitions of copy/const prop and PRE to run.  */
 217 DEFPARAM(PARAM_MAX_GCSE_PASSES,
 218         "max-gcse-passes",
 219         "The maximum number of passes to make when doing GCSE",
 220         1, 1, 0)
 221 /* This is the threshold ratio when to perform partial redundancy
 222    elimination after reload. We perform partial redundancy elimination
 223    when the following holds:
 224    (Redundant load execution count)
 225    ------------------------------- >= GCSE_AFTER_RELOAD_PARTIAL_FRACTION
 226    (Added loads execution count)                                          */
 227 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_PARTIAL_FRACTION,
 228         "gcse-after-reload-partial-fraction",
 229         "The threshold ratio for performing partial redundancy elimination after reload",
 230         3, 0, 0)
 231 /* This is the threshold ratio of the critical edges execution count compared to
 232    the redundant loads execution count that permits performing the load
 233    redundancy elimination in gcse after reload.  */
 234 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_CRITICAL_FRACTION,
 235         "gcse-after-reload-critical-fraction",
 236         "The threshold ratio of critical edges execution count that permit performing redundancy elimination after reload",
 237         10, 0, 0)
 238 /* This parameter limits the number of insns in a loop that will be unrolled,
 239    and by how much the loop is unrolled.
 240
 241    This limit should be at most half of the peeling limits:  loop unroller
 242    decides to not unroll loops that iterate fewer than 2*number of allowed
 243    unrollings and thus we would have loops that are neither peeled or unrolled
 244    otherwise.  */
 245 DEFPARAM(PARAM_MAX_UNROLLED_INSNS,
 246          "max-unrolled-insns",
 247          "The maximum number of instructions to consider to unroll in a loop",
 248          200, 0, 0)
 249 /* This parameter limits how many times the loop is unrolled depending
 250    on number of insns really executed in each iteration.  */
 251 DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS,
 252          "max-average-unrolled-insns",
 253          "The maximum number of instructions to consider to unroll in a loop on average",
 254          80, 0, 0)
 255 /* The maximum number of unrollings of a single loop.  */
 256 DEFPARAM(PARAM_MAX_UNROLL_TIMES,
 257         "max-unroll-times",
 258         "The maximum number of unrollings of a single loop",
 259         8, 0, 0)
 260 /* The maximum number of insns of a peeled loop.  */
 261 DEFPARAM(PARAM_MAX_PEELED_INSNS,
 262         "max-peeled-insns",
 263         "The maximum number of insns of a peeled loop",
 264         400, 0, 0)
 265 /* The maximum number of peelings of a single loop.  */
 266 DEFPARAM(PARAM_MAX_PEEL_TIMES,
 267         "max-peel-times",
 268         "The maximum number of peelings of a single loop",
 269         16, 0, 0)
 270 /* The maximum number of insns of a peeled loop.  */
 271 DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS,
 272         "max-completely-peeled-insns",
 273         "The maximum number of insns of a completely peeled loop",
 274         400, 0, 0)
 275 /* The maximum number of peelings of a single loop that is peeled completely.  */
 276 DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES,
 277         "max-completely-peel-times",
 278         "The maximum number of peelings of a single loop that is peeled completely",
 279         16, 0, 0)
 280 /* The maximum number of insns of a peeled loop that rolls only once.  */
 281 DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS,
 282         "max-once-peeled-insns",
 283         "The maximum number of insns of a peeled loop that rolls only once",
 284         400, 0, 0)
 285
 286 /* The maximum number of insns of an unswitched loop.  */
 287 DEFPARAM(PARAM_MAX_UNSWITCH_INSNS,
 288         "max-unswitch-insns",
 289         "The maximum number of insns of an unswitched loop",
 290         50, 0, 0)
 291 /* The maximum level of recursion in unswitch_single_loop.  */
 292 DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL,
 293         "max-unswitch-level",
 294         "The maximum number of unswitchings in a single loop",
 295         3, 0, 0)
 296
 297 /* The maximum number of iterations of a loop the brute force algorithm
 298    for analysis of # of iterations of the loop tries to evaluate.  */
 299 DEFPARAM(PARAM_MAX_ITERATIONS_TO_TRACK,
 300         "max-iterations-to-track",
 301         "Bound on the number of iterations the brute force # of iterations analysis algorithm evaluates",
 302         1000, 0, 0)
 303 /* A cutoff to avoid costly computations of the number of iterations in
 304    the doloop transformation.  */
 305 DEFPARAM(PARAM_MAX_ITERATIONS_COMPUTATION_COST,
 306         "max-iterations-computation-cost",
 307         "Bound on the cost of an expression to compute the number of iterations",
 308         10, 0, 0)
 309
 310 DEFPARAM(PARAM_MAX_SMS_LOOP_NUMBER,
 311          "max-sms-loop-number",
 312          "Maximum number of loops to perform swing modulo scheduling on (mainly for debugging)",
 313          -1, -1, -1)
 314
 315 /* This parameter is used to tune SMS MAX II calculations.  */
 316 DEFPARAM(PARAM_SMS_MAX_II_FACTOR,
 317          "sms-max-ii-factor",
 318          "A factor for tuning the upper bound that swing modulo scheduler uses for scheduling a loop",
 319          100, 0, 0)
 320 DEFPARAM(PARAM_SMS_DFA_HISTORY,
 321          "sms-dfa-history",
 322          "The number of cycles the swing modulo scheduler considers when checking conflicts using DFA",
 323          0, 0, 0)
 324 DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD,
 325          "sms-loop-average-count-threshold",
 326          "A threshold on the average loop count considered by the swing modulo scheduler",
 327          0, 0, 0)
 328
 329 DEFPARAM(HOT_BB_COUNT_FRACTION,
 330          "hot-bb-count-fraction",
 331          "Select fraction of the maximal count of repetitions of basic block in program given basic block needs to have to be considered hot",
 332          10000, 0, 0)
 333 DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
 334          "hot-bb-frequency-fraction",
 335          "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot",
 336          1000, 0, 0)
 337
 338 /* For guessed profiles, the loops having unknown number of iterations
 339    are predicted to iterate relatively few (10) times at average.
 340    For functions containing one loop with large known number of iterations
 341    and other loops having unbounded loops we would end up predicting all
 342    the other loops cold that is not usually the case.  So we need to artificially
 343    flatten the profile.
 344
 345    We need to cut the maximal predicted iterations to large enough iterations
 346    so the loop appears important, but safely within HOT_BB_COUNT_FRACTION
 347    range.  */
 348
 349 DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS,
 350          "max-predicted-iterations",
 351          "The maximum number of loop iterations we predict statically",
 352          100, 0, 0)
 353 DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
 354          "tracer-dynamic-coverage-feedback",
 355          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available",
 356          95, 0, 100)
 357 DEFPARAM(TRACER_DYNAMIC_COVERAGE,
 358          "tracer-dynamic-coverage",
 359          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available",
 360          75, 0, 100)
 361 DEFPARAM(TRACER_MAX_CODE_GROWTH,
 362          "tracer-max-code-growth",
 363          "Maximal code growth caused by tail duplication (in percent)",
 364          100, 0, 0)
 365 DEFPARAM(TRACER_MIN_BRANCH_RATIO,
 366          "tracer-min-branch-ratio",
 367          "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent)",
 368          10, 0, 100)
 369 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
 370          "tracer-min-branch-probability-feedback",
 371          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available",
 372          80, 0, 100)
 373 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
 374          "tracer-min-branch-probability",
 375          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available",
 376          50, 0, 100)
 377
 378 /* The maximum number of incoming edges to consider for crossjumping.  */
 379 DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
 380          "max-crossjump-edges",
 381          "The maximum number of incoming edges to consider for crossjumping",
 382          100, 0, 0)
 383
 384 /* The minimum number of matching instructions to consider for crossjumping.  */
 385 DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS,
 386      "min-crossjump-insns",
 387      "The minimum number of matching instructions to consider for crossjumping",
 388      5, 0, 0)
 389
 390 /* The maximum number expansion factor when copying basic blocks.  */
 391 DEFPARAM(PARAM_MAX_GROW_COPY_BB_INSNS,
 392      "max-grow-copy-bb-insns",
 393      "The maximum expansion factor when copying basic blocks",
 394      8, 0, 0)
 395
 396 /* The maximum number of insns to duplicate when unfactoring computed gotos.  */
 397 DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS,
 398      "max-goto-duplication-insns",
 399      "The maximum number of insns to duplicate when unfactoring computed gotos",
 400      8, 0, 0)
 401
 402 /* The maximum length of path considered in cse.  */
 403 DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
 404          "max-cse-path-length",
 405          "The maximum length of path considered in cse",
 406          10, 0, 0)
 407 DEFPARAM(PARAM_MAX_CSE_INSNS,
 408          "max-cse-insns",
 409          "The maximum instructions CSE process before flushing",
 410          1000, 0, 0)
 411
 412 /* The cost of expression in loop invariant motion that is considered
 413    expensive.  */
 414 DEFPARAM(PARAM_LIM_EXPENSIVE,
 415          "lim-expensive",
 416          "The minimum cost of an expensive expression in the loop invariant motion",
 417          20, 0, 0)
 418
 419 /* Bound on number of candidates for induction variables below that
 420    all candidates are considered for each use in induction variable
 421    optimizations.  */
 422
 423 DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND,
 424          "iv-consider-all-candidates-bound",
 425          "Bound on number of candidates below that all candidates are considered in iv optimizations",
 426          30, 0, 0)
 427
 428 /* The induction variable optimizations give up on loops that contain more
 429    induction variable uses.  */
 430
 431 DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES,
 432          "iv-max-considered-uses",
 433          "Bound on number of iv uses in loop optimized in iv optimizations",
 434          250, 0, 0)
 435
 436 /* If there are at most this number of ivs in the set, try removing unnecessary
 437    ivs from the set always.  */
 438
 439 DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND,
 440          "iv-always-prune-cand-set-bound",
 441          "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization",
 442          10, 0, 0)
 443
 444 DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE,
 445          "scev-max-expr-size",
 446          "Bound on size of expressions used in the scalar evolutions analyzer",
 447          20, 0, 0)
 448
 449 DEFPARAM(PARAM_VECT_MAX_VERSION_CHECKS,
 450          "vect-max-version-checks",
 451          "Bound on number of runtime checks inserted by the vectorizer's loop versioning",
 452          6, 0, 0)
 453
 454 DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS,
 455          "max-cselib-memory-locations",
 456          "The maximum memory locations recorded by cselib",
 457          500, 0, 0)
 458 DEFPARAM(PARAM_MAX_FLOW_MEMORY_LOCATIONS,
 459          "max-flow-memory-locations",
 460          "The maximum memory locations recorded by flow",
 461          100, 0, 0)
 462
 463 #ifdef ENABLE_GC_ALWAYS_COLLECT
 464 # define GGC_MIN_EXPAND_DEFAULT 0
 465 # define GGC_MIN_HEAPSIZE_DEFAULT 0
 466 #else
 467 # define GGC_MIN_EXPAND_DEFAULT 30
 468 # define GGC_MIN_HEAPSIZE_DEFAULT 4096
 469 #endif
 470
 471 DEFPARAM(GGC_MIN_EXPAND,
 472          "ggc-min-expand",
 473          "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap",
 474          GGC_MIN_EXPAND_DEFAULT, 0, 0)
 475
 476 DEFPARAM(GGC_MIN_HEAPSIZE,
 477          "ggc-min-heapsize",
 478          "Minimum heap size before we start collecting garbage, in kilobytes",
 479          GGC_MIN_HEAPSIZE_DEFAULT, 0, 0)
 480
 481 #undef GGC_MIN_EXPAND_DEFAULT
 482 #undef GGC_MIN_HEAPSIZE_DEFAULT
 483
 484 DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
 485          "max-reload-search-insns",
 486          "The maximum number of instructions to search backward when looking for equivalent reload",
 487          100, 0, 0)
 488
 489 DEFPARAM(PARAM_MAX_ALIASED_VOPS,
 490          "max-aliased-vops",
 491          "The maximum number of virtual operators per statement allowed to represent aliases before triggering alias grouping",
 492          10, 0, 0)
 493
 494 DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS,
 495          "max-sched-region-blocks",
 496          "The maximum number of blocks in a region to be considered for interblock scheduling",
 497          10, 0, 0)
 498
 499 DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS,
 500          "max-sched-region-insns",
 501          "The maximum number of insns in a region to be considered for interblock scheduling",
 502          100, 0, 0)
 503
 504 DEFPARAM(PARAM_MIN_SPEC_PROB,
 505          "min-spec-prob",
 506          "The minimum probability of reaching a source block for interblock speculative scheduling",
 507          40, 0, 0)
 508
 509 DEFPARAM(PARAM_MAX_SCHED_EXTEND_REGIONS_ITERS,
 510          "max-sched-extend-regions-iters",
 511          "The maximum number of iterations through CFG to extend regions",
 512          0, 0, 0)
 513
 514 DEFPARAM(PARAM_MAX_SCHED_INSN_CONFLICT_DELAY,
 515          "max-sched-insn-conflict-delay",
 516          "The maximum conflict delay for an insn to be considered for speculative motion",
 517          3, 1, 10)
 518
 519 DEFPARAM(PARAM_SCHED_SPEC_PROB_CUTOFF,
 520          "sched-spec-prob-cutoff",
 521          "The minimal probability of speculation success (in percents), so that speculative insn will be scheduled.",
 522          40, 0, 100)
 523
 524 DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
 525          "max-last-value-rtl",
 526          "The maximum number of RTL nodes that can be recorded as combiner's last value",
 527          10000, 0, 0)
 528
 529 /* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
 530    {signed,unsigned} integral types.  This determines N.
 531    Experimentation shows 256 to be a good value.  */
 532 DEFPARAM (PARAM_INTEGER_SHARE_LIMIT,
 533           "integer-share-limit",
 534           "The upper bound for sharing integer constants",
 535           256, 2, 2)
 536
 537 /* Incremental SSA updates for virtual operands may be very slow if
 538    there is a large number of mappings to process.  In those cases, it
 539    is faster to rewrite the virtual symbols from scratch as if they
 540    had been recently introduced.  This heuristic cannot be applied to
 541    SSA mappings for real SSA names, only symbols kept in FUD chains.
 542
 543    PARAM_MIN_VIRTUAL_MAPPINGS specifies the minimum number of virtual
 544    mappings that should be registered to trigger the heuristic.
 545
 546    PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO specifies the ratio between
 547    mappings and symbols.  If the number of virtual mappings is
 548    PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO bigger than the number of
 549    virtual symbols to be updated, then the updater switches to a full
 550    update for those symbols.  */
 551 DEFPARAM (PARAM_MIN_VIRTUAL_MAPPINGS,
 552           "min-virtual-mappings",
 553           "Minimum number of virtual mappings to consider switching to full virtual renames",
 554           100, 0, 0)
 555
 556 DEFPARAM (PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO,
 557           "virtual-mappings-ratio",
 558           "Ratio between virtual mappings and virtual symbols to do full virtual renames",
 559           3, 0, 0)
 560
 561 DEFPARAM (PARAM_SSP_BUFFER_SIZE,
 562           "ssp-buffer-size",
 563           "The lower bound for a buffer to be considered for stack smashing protection",
 564           8, 1, 0)
 565
 566 /* When we thread through a block we have to make copies of the
 567    statements within the block.  Clearly for large blocks the code
 568    duplication is bad.
 569
 570    PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number
 571    of statements and PHI nodes allowed in a block which is going to
 572    be duplicated for thread jumping purposes.
 573
 574    Some simple analysis showed that more than 99% of the jump
 575    threading opportunities are for blocks with less than 15
 576    statements.  So we can get the benefits of jump threading
 577    without excessive code bloat for pathological cases with the
 578    throttle set at 15 statements.  */
 579 DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS,
 580           "max-jump-thread-duplication-stmts",
 581           "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps",
 582           15, 0, 0)
 583
 584 /* This is the maximum number of fields a variable may have before the pointer analysis machinery
 585    will stop trying to treat it in a field-sensitive manner.
 586    There are programs out there with thousands of fields per structure, and handling them
 587    field-sensitively is not worth the cost.  */
 588 DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE,
 589           "max-fields-for-field-sensitive",
 590           "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable",
 591           100, 0, 0)
 592
 593 DEFPARAM(PARAM_MAX_SCHED_READY_INSNS,
 594          "max-sched-ready-insns",
 595          "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass",
 596          100, 0, 0)
 597
 598 /* Prefetching and cache-optimizations related parameters.  Default values are
 599    usually set by machine description.  */
 600
 601 /* The number of insns executed before prefetch is completed.  */
 602
 603 DEFPARAM (PARAM_PREFETCH_LATENCY,
 604          "prefetch-latency",
 605          "The number of insns executed before prefetch is completed",
 606          200, 0, 0)
 607
 608 /* The number of prefetches that can run at the same time.  */
 609
 610 DEFPARAM (PARAM_SIMULTANEOUS_PREFETCHES,
 611           "simultaneous-prefetches",
 612           "The number of prefetches that can run at the same time",
 613           3, 0, 0)
 614
 615 /* The size of L1 cache in number of cache lines.  */
 616
 617 DEFPARAM (PARAM_L1_CACHE_SIZE,
 618           "l1-cache-size",
 619           "The size of L1 cache",
 620           1024, 0, 0)
 621
 622 /* The size of L1 cache line in bytes.  */
 623
 624 DEFPARAM (PARAM_L1_CACHE_LINE_SIZE,
 625           "l1-cache-line-size",
 626           "The size of L1 cache line",
 627           32, 0, 0)
 628
 629 #ifdef ENABLE_CHECKING
 630 # define GCC_CANONICAL_TYPES_DEFAULT 1
 631 #else
 632 # define GCC_CANONICAL_TYPES_DEFAULT 0
 633 #endif
 634
 635 /* Whether we should verify that the canonical types in the system are
 636    consistent with the "structural" typing. */
 637
 638 DEFPARAM (PARAM_VERIFY_CANONICAL_TYPES,
 639           "verify-canonical-types",
 640           "Whether to verify canonical types",
 641           GCC_CANONICAL_TYPES_DEFAULT, 0, 1)
 642 /*
 643 Local variables:
 644 mode:c
 645 End: */