gcc/params.def

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