gcc/params.def

   1 /* params.def - Run-time parameters.
   2    Copyright (C) 2001-2019 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    The DEFPARAMENUM<N> macro is similar, but instead of the minumum and maximum
  39    arguments, it contains a list of <N> allowed strings, corresponding to
  40    integer values 0..<N>-1.  Note that the default argument needs to be
  41    specified as one of the allowed strings, rather than an integer value.
  42
  43    Be sure to add an entry to invoke.texi summarizing the parameter.  */
  44
  45 /* When branch is predicted to be taken with probability lower than this
  46    threshold (in percent), then it is considered well predictable. */
  47 DEFPARAM (PARAM_PREDICTABLE_BRANCH_OUTCOME,
  48           "predictable-branch-outcome",
  49           "Maximal estimated outcome of branch considered predictable.",
  50           2, 0, 50)
  51
  52 DEFPARAM (PARAM_INLINE_MIN_SPEEDUP,
  53           "inline-min-speedup",
  54           "The minimal estimated speedup allowing inliner to ignore inline-insns-single and inline-insns-auto.",
  55           15, 0, 0)
  56
  57 /* The single function inlining limit. This is the maximum size
  58    of a function counted in internal gcc instructions (not in
  59    real machine instructions) that is eligible for inlining
  60    by the tree inliner.
  61    Only functions marked inline (or methods defined in the class
  62    definition for C++) are affected by this.
  63    There are more restrictions to inlining: If inlined functions
  64    call other functions, the already inlined instructions are
  65    counted and once the recursive inline limit (see
  66    "max-inline-insns" parameter) is exceeded, the acceptable size
  67    gets decreased.  */
  68 DEFPARAM (PARAM_MAX_INLINE_INSNS_SINGLE,
  69           "max-inline-insns-single",
  70           "The maximum number of instructions in a single function eligible for inlining.",
  71           200, 0, 0)
  72
  73 /* The single function inlining limit for functions that are
  74    inlined by virtue of -finline-functions (-O3).
  75    This limit should be chosen to be below or equal to the limit
  76    that is applied to functions marked inlined (or defined in the
  77    class declaration in C++) given by the "max-inline-insns-single"
  78    parameter.
  79    The default value is 30.  */
  80 DEFPARAM (PARAM_MAX_INLINE_INSNS_AUTO,
  81           "max-inline-insns-auto",
  82           "The maximum number of instructions when automatically inlining.",
  83           30, 0, 0)
  84
  85 DEFPARAM (PARAM_MAX_INLINE_INSNS_SMALL,
  86           "max-inline-insns-small",
  87           "The maximum number of instructions when automatically inlining small functions.",
  88           0, 0, 0)
  89
  90 DEFPARAM (PARAM_MAX_INLINE_INSNS_SIZE,
  91           "max-inline-insns-size",
  92           "The maximum number of instructions when inlining for size.",
  93           0, 0, 0)
  94
  95 DEFPARAM (PARAM_UNINLINED_FUNCTION_INSNS,
  96           "uninlined-function-insns",
  97           "Instruction accounted for function prologue, epilogue and other"
  98           " overhead.",
  99           2, 0, 1000000)
 100
 101 DEFPARAM (PARAM_UNINLINED_FUNCTION_TIME,
 102           "uninlined-function-time",
 103           "Time accounted for function prologue, epilogue and other"
 104           " overhead.",
 105           0, 0, 1000000)
 106
 107 DEFPARAM (PARAM_UNINLINED_FUNCTION_THUNK_INSNS,
 108           "uninlined-thunk-insns",
 109           "Instruction accounted for function thunk overhead.",
 110           2, 0, 1000000)
 111
 112 DEFPARAM (PARAM_UNINLINED_FUNCTION_THUNK_TIME,
 113           "uninlined-thunk-time",
 114           "Time accounted for function thunk overhead.",
 115           2, 0, 1000000)
 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 of iterations of early inliner.  This basically bounds number of
 143    nested indirect calls early inliner can resolve.  Deeper chains are still
 144    handled by late inlining.  */
 145 DEFPARAM (PARAM_EARLY_INLINER_MAX_ITERATIONS,
 146           "max-early-inliner-iterations",
 147           "The maximum number of nested indirect inlining performed by early inliner.",
 148           1, 0, 0)
 149
 150 /* Limit on probability of entry BB.  */
 151 DEFPARAM (PARAM_COMDAT_SHARING_PROBABILITY,
 152           "comdat-sharing-probability",
 153           "Probability that COMDAT function will be shared with different compilation unit.",
 154           20, 0, 0)
 155
 156 /* Limit on probability of entry BB.  */
 157 DEFPARAM (PARAM_PARTIAL_INLINING_ENTRY_PROBABILITY,
 158           "partial-inlining-entry-probability",
 159           "Maximum probability of the entry BB of split region (in percent relative to entry BB of the function) to make partial inlining happen.",
 160           70, 0, 100)
 161
 162 /* Limit the number of expansions created by the variable expansion
 163    optimization to avoid register pressure.  */
 164 DEFPARAM (PARAM_MAX_VARIABLE_EXPANSIONS,
 165           "max-variable-expansions-in-unroller",
 166           "If -fvariable-expansion-in-unroller is used, the maximum number of times that an individual variable will be expanded during loop unrolling.",
 167           1, 0, 0)
 168
 169 /* Limit loop autovectorization to loops with large enough iteration count.  */
 170 DEFPARAM (PARAM_MIN_VECT_LOOP_BOUND,
 171           "min-vect-loop-bound",
 172           "If -ftree-vectorize is used, the minimal loop bound of a loop to be considered for vectorization.",
 173           0, 0, 0)
 174
 175 /* The maximum number of instructions to consider when looking for an
 176    instruction to fill a delay slot.  If more than this arbitrary
 177    number of instructions is searched, the time savings from filling
 178    the delay slot will be minimal so stop searching.  Increasing
 179    values mean more aggressive optimization, making the compile time
 180    increase with probably small improvement in executable run time.  */
 181 DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH,
 182           "max-delay-slot-insn-search",
 183           "The maximum number of instructions to consider to fill a delay slot.",
 184           100, 0, 0)
 185
 186 /* When trying to fill delay slots, the maximum number of instructions
 187    to consider when searching for a block with valid live register
 188    information.  Increasing this arbitrarily chosen value means more
 189    aggressive optimization, increasing the compile time.  This
 190    parameter should be removed when the delay slot code is rewritten
 191    to maintain the control-flow graph.  */
 192 DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH,
 193          "max-delay-slot-live-search",
 194          "The maximum number of instructions to consider to find accurate live register information.",
 195          333, 0, 0)
 196
 197 /* This parameter limits the number of branch elements that the
 198    scheduler will track anti-dependencies through without resetting
 199    the tracking mechanism.  Large functions with few calls or barriers
 200    can generate lists containing many 1000's of dependencies.  Generally
 201    the compiler either uses all available memory, or runs for far too long.  */
 202 DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH,
 203          "max-pending-list-length",
 204          "The maximum length of scheduling's pending operations list.",
 205          32, 0, 0)
 206
 207 /* This parameter limits the number of backtracking attempts when using the
 208    haifa scheduler for modulo scheduling.  */
 209 DEFPARAM(PARAM_MAX_MODULO_BACKTRACK_ATTEMPTS,
 210          "max-modulo-backtrack-attempts",
 211          "The maximum number of backtrack attempts the scheduler should make when modulo scheduling a loop.",
 212          40, 0, 0)
 213
 214 DEFPARAM(PARAM_LARGE_FUNCTION_INSNS,
 215          "large-function-insns",
 216          "The size of function body to be considered large.",
 217          2700, 0, 0)
 218 DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH,
 219          "large-function-growth",
 220          "Maximal growth due to inlining of large function (in percent).",
 221          100, 0, 0)
 222 DEFPARAM(PARAM_LARGE_UNIT_INSNS,
 223          "large-unit-insns",
 224          "The size of translation unit to be considered large.",
 225          10000, 0, 0)
 226 DEFPARAM(PARAM_INLINE_UNIT_GROWTH,
 227          "inline-unit-growth",
 228          "How much can given compilation unit grow because of the inlining (in percent).",
 229          40, 0, 0)
 230 DEFPARAM(PARAM_IPCP_UNIT_GROWTH,
 231          "ipcp-unit-growth",
 232          "How much can given compilation unit grow because of the interprocedural constant propagation (in percent).",
 233          10, 0, 0)
 234 DEFPARAM(PARAM_EARLY_INLINING_INSNS,
 235          "early-inlining-insns",
 236          "Maximal estimated growth of function body caused by early inlining of single call.",
 237          14, 0, 0)
 238 DEFPARAM(PARAM_LARGE_STACK_FRAME,
 239          "large-stack-frame",
 240          "The size of stack frame to be considered large.",
 241          256, 0, 0)
 242 DEFPARAM(PARAM_STACK_FRAME_GROWTH,
 243          "large-stack-frame-growth",
 244          "Maximal stack frame growth due to inlining (in percent).",
 245          1000, 0, 0)
 246
 247 /* Keep these up to date with those in configure.ac.  */
 248 DEFPARAM(PARAM_STACK_CLASH_PROTECTION_GUARD_SIZE,
 249          "stack-clash-protection-guard-size",
 250          "Size of the stack guard expressed as a power of two in bytes.",
 251          12, 12, 30)
 252
 253 DEFPARAM(PARAM_STACK_CLASH_PROTECTION_PROBE_INTERVAL,
 254          "stack-clash-protection-probe-interval",
 255          "Interval in which to probe the stack expressed as a power of two in bytes.",
 256          12, 10, 16)
 257
 258 /* The GCSE optimization will be disabled if it would require
 259    significantly more memory than this value.  */
 260 DEFPARAM(PARAM_MAX_GCSE_MEMORY,
 261          "max-gcse-memory",
 262          "The maximum amount of memory to be allocated by GCSE.",
 263          128 * 1024 * 1024, 0, 0)
 264
 265 /* The GCSE optimization of an expression will avoided if the ratio of
 266    insertions to deletions is greater than this value.  */
 267 DEFPARAM(PARAM_MAX_GCSE_INSERTION_RATIO,
 268          "max-gcse-insertion-ratio",
 269          "The maximum ratio of insertions to deletions of expressions in GCSE.",
 270          20, 0, 0)
 271
 272 /* This is the threshold ratio when to perform partial redundancy
 273    elimination after reload. We perform partial redundancy elimination
 274    when the following holds:
 275    (Redundant load execution count)
 276    ------------------------------- >= GCSE_AFTER_RELOAD_PARTIAL_FRACTION
 277    (Added loads execution count)                                          */
 278 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_PARTIAL_FRACTION,
 279         "gcse-after-reload-partial-fraction",
 280         "The threshold ratio for performing partial redundancy elimination after reload.",
 281         3, 0, 0)
 282 /* This is the threshold ratio of the critical edges execution count compared to
 283    the redundant loads execution count that permits performing the load
 284    redundancy elimination in gcse after reload.  */
 285 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_CRITICAL_FRACTION,
 286         "gcse-after-reload-critical-fraction",
 287         "The threshold ratio of critical edges execution count that permit performing redundancy elimination after reload.",
 288         10, 0, 0)
 289
 290 /* GCSE will use GCSE_COST_DISTANCE_RATION as a scaling factor
 291    to calculate maximum distance for which an expression is allowed to move
 292    from its rtx_cost.  */
 293 DEFPARAM(PARAM_GCSE_COST_DISTANCE_RATIO,
 294          "gcse-cost-distance-ratio",
 295          "Scaling factor in calculation of maximum distance an expression can be moved by GCSE optimizations.",
 296          10, 0, 0)
 297 /* GCSE won't restrict distance for which an expression with rtx_cost greater
 298    than COSTS_N_INSN(GCSE_UNRESTRICTED_COST) is allowed to move.  */
 299 DEFPARAM(PARAM_GCSE_UNRESTRICTED_COST,
 300          "gcse-unrestricted-cost",
 301          "Cost at which GCSE optimizations will not constraint the distance an expression can travel.",
 302          3, 0, 0)
 303
 304 /* How deep from a given basic block the dominator tree should be searched
 305    for expressions to hoist to the block.  The value of 0 will avoid limiting
 306    the search.  */
 307 DEFPARAM(PARAM_MAX_HOIST_DEPTH,
 308          "max-hoist-depth",
 309          "Maximum depth of search in the dominator tree for expressions to hoist.",
 310          30, 0, 0)
 311
 312
 313 /* When synthesizing expnonentiation by a real constant operations using square
 314    roots, this controls how deep sqrt chains we are willing to generate.  */
 315 DEFPARAM(PARAM_MAX_POW_SQRT_DEPTH,
 316          "max-pow-sqrt-depth",
 317          "Maximum depth of sqrt chains to use when synthesizing exponentiation by a real constant.",
 318          5, 1, 32)
 319
 320 /* This parameter limits the number of insns in a loop that will be unrolled,
 321    and by how much the loop is unrolled.
 322
 323    This limit should be at most half of the peeling limits:  loop unroller
 324    decides to not unroll loops that iterate fewer than 2*number of allowed
 325    unrollings and thus we would have loops that are neither peeled or unrolled
 326    otherwise.  */
 327 DEFPARAM(PARAM_MAX_UNROLLED_INSNS,
 328          "max-unrolled-insns",
 329          "The maximum number of instructions to consider to unroll in a loop.",
 330          200, 0, 0)
 331 /* This parameter limits how many times the loop is unrolled depending
 332    on number of insns really executed in each iteration.  */
 333 DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS,
 334          "max-average-unrolled-insns",
 335          "The maximum number of instructions to consider to unroll in a loop on average.",
 336          80, 0, 0)
 337 /* The maximum number of unrollings of a single loop.  */
 338 DEFPARAM(PARAM_MAX_UNROLL_TIMES,
 339         "max-unroll-times",
 340         "The maximum number of unrollings of a single loop.",
 341         8, 0, 0)
 342 /* The maximum number of insns of a peeled loop.  */
 343 DEFPARAM(PARAM_MAX_PEELED_INSNS,
 344         "max-peeled-insns",
 345         "The maximum number of insns of a peeled loop.",
 346         100, 0, 0)
 347 /* The maximum number of peelings of a single loop.  */
 348 DEFPARAM(PARAM_MAX_PEEL_TIMES,
 349         "max-peel-times",
 350         "The maximum number of peelings of a single loop.",
 351         16, 0, 0)
 352 /* The maximum number of peelings of a single loop that is peeled completely.  */
 353 DEFPARAM(PARAM_MAX_PEEL_BRANCHES,
 354         "max-peel-branches",
 355         "The maximum number of branches on the path through the peeled sequence.",
 356         32, 0, 0)
 357 /* The maximum number of insns of a peeled loop.  */
 358 DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS,
 359         "max-completely-peeled-insns",
 360         "The maximum number of insns of a completely peeled loop.",
 361         200, 0, 0)
 362 /* The maximum number of peelings of a single loop that is peeled completely.  */
 363 DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES,
 364         "max-completely-peel-times",
 365         "The maximum number of peelings of a single loop that is peeled completely.",
 366         16, 0, 0)
 367 /* The maximum number of insns of a peeled loop that rolls only once.  */
 368 DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS,
 369         "max-once-peeled-insns",
 370         "The maximum number of insns of a peeled loop that rolls only once.",
 371         400, 0, 0)
 372 /* The maximum depth of a loop nest we completely peel.  */
 373 DEFPARAM(PARAM_MAX_UNROLL_ITERATIONS,
 374          "max-completely-peel-loop-nest-depth",
 375          "The maximum depth of a loop nest we completely peel.",
 376          8, 0, 0)
 377
 378 /* The maximum number of insns of an unswitched loop.  */
 379 DEFPARAM(PARAM_MAX_UNSWITCH_INSNS,
 380         "max-unswitch-insns",
 381         "The maximum number of insns of an unswitched loop.",
 382         50, 0, 0)
 383 /* The maximum level of recursion in unswitch_single_loop.  */
 384 DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL,
 385         "max-unswitch-level",
 386         "The maximum number of unswitchings in a single loop.",
 387         3, 0, 0)
 388
 389 /* The maximum number of insns in loop header duplicated by the copy loop
 390    headers pass.  */
 391 DEFPARAM(PARAM_MAX_LOOP_HEADER_INSNS,
 392         "max-loop-header-insns",
 393         "The maximum number of insns in loop header duplicated by the copy loop headers pass.",
 394         20, 0, 0)
 395
 396 /* The maximum number of iterations of a loop the brute force algorithm
 397    for analysis of # of iterations of the loop tries to evaluate.  */
 398 DEFPARAM(PARAM_MAX_ITERATIONS_TO_TRACK,
 399         "max-iterations-to-track",
 400         "Bound on the number of iterations the brute force # of iterations analysis algorithm evaluates.",
 401         1000, 0, 0)
 402 /* A cutoff to avoid costly computations of the number of iterations in
 403    the doloop transformation.  */
 404 DEFPARAM(PARAM_MAX_ITERATIONS_COMPUTATION_COST,
 405         "max-iterations-computation-cost",
 406         "Bound on the cost of an expression to compute the number of iterations.",
 407         10, 0, 0)
 408
 409 /* This parameter is used to tune SMS MAX II calculations.  */
 410 DEFPARAM(PARAM_SMS_MAX_II_FACTOR,
 411          "sms-max-ii-factor",
 412          "A factor for tuning the upper bound that swing modulo scheduler uses for scheduling a loop.",
 413          100, 0, 0)
 414 /* The minimum value of stage count that swing modulo scheduler will generate.  */
 415 DEFPARAM(PARAM_SMS_MIN_SC,
 416         "sms-min-sc",
 417         "The minimum value of stage count that swing modulo scheduler will generate.",
 418         2, 1, 1)
 419 DEFPARAM(PARAM_SMS_DFA_HISTORY,
 420          "sms-dfa-history",
 421          "The number of cycles the swing modulo scheduler considers when checking conflicts using DFA.",
 422          0, 0, 0)
 423 DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD,
 424          "sms-loop-average-count-threshold",
 425          "A threshold on the average loop count considered by the swing modulo scheduler.",
 426          0, 0, 0)
 427
 428 DEFPARAM(HOT_BB_COUNT_FRACTION,
 429          "hot-bb-count-fraction",
 430          "Select fraction of the maximal count of repetitions of basic block in program given basic "
 431          "block needs to have to be considered hot (used in non-LTO mode).",
 432          10000, 0, 0)
 433 DEFPARAM(HOT_BB_COUNT_WS_PERMILLE,
 434          "hot-bb-count-ws-permille",
 435          "A basic block profile count is considered hot if it contributes to "
 436          "the given permillage of the entire profiled execution (used in LTO mode).",
 437          990, 0, 1000)
 438 DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
 439          "hot-bb-frequency-fraction",
 440          "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot.",
 441          1000, 0, 0)
 442
 443 DEFPARAM(UNLIKELY_BB_COUNT_FRACTION,
 444          "unlikely-bb-count-fraction",
 445          "The minimum fraction of profile runs a given basic block execution count must be not to be considered unlikely.",
 446          20, 1, 10000)
 447
 448 DEFPARAM (PARAM_ALIGN_THRESHOLD,
 449           "align-threshold",
 450           "Select fraction of the maximal frequency of executions of basic block in function given basic block get alignment.",
 451           100, 1, 0)
 452
 453 DEFPARAM (PARAM_ALIGN_LOOP_ITERATIONS,
 454           "align-loop-iterations",
 455           "Loops iterating at least selected number of iterations will get "
 456           "loop alignment.", 4, 0, 0)
 457
 458 /* For guessed profiles, the loops having unknown number of iterations
 459    are predicted to iterate relatively few (10) times at average.
 460    For functions containing one loop with large known number of iterations
 461    and other loops having unbounded loops we would end up predicting all
 462    the other loops cold that is not usually the case.  So we need to artificially
 463    flatten the profile.
 464
 465    We need to cut the maximal predicted iterations to large enough iterations
 466    so the loop appears important, but safely within maximum hotness
 467    range.  */
 468
 469 DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS,
 470          "max-predicted-iterations",
 471          "The maximum number of loop iterations we predict statically.",
 472          100, 0, 0)
 473
 474 /* This parameter controls the probability of builtin_expect. The default
 475    value is 90%. This empirical value is obtained through the weighted
 476    probability of FDO counters (with the FDO count value as the weight)
 477    in some real world programs:
 478    (1) Google performance test benchmarks: the probability is 0.9081.
 479    (2) Linux 3.3 kernel running Google search workload: the probability
 480    is 0.8717.  */
 481
 482 DEFPARAM(BUILTIN_EXPECT_PROBABILITY,
 483          "builtin-expect-probability",
 484          "Set the estimated probability in percentage for builtin expect. The default value is 90% probability.",
 485          90, 0, 100)
 486 DEFPARAM(BUILTIN_STRING_CMP_INLINE_LENGTH,
 487          "builtin-string-cmp-inline-length",
 488          "The maximum length of a constant string for a builtin string cmp call eligible for inlining. The default value is 3.",
 489          3, 0, 100)
 490 DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
 491          "tracer-dynamic-coverage-feedback",
 492          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available.",
 493          95, 0, 100)
 494 DEFPARAM(TRACER_DYNAMIC_COVERAGE,
 495          "tracer-dynamic-coverage",
 496          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available.",
 497          75, 0, 100)
 498 DEFPARAM(TRACER_MAX_CODE_GROWTH,
 499          "tracer-max-code-growth",
 500          "Maximal code growth caused by tail duplication (in percent).",
 501          100, 0, 0)
 502 DEFPARAM(TRACER_MIN_BRANCH_RATIO,
 503          "tracer-min-branch-ratio",
 504          "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent).",
 505          10, 0, 100)
 506 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
 507          "tracer-min-branch-probability-feedback",
 508          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available.",
 509          80, 0, 100)
 510 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
 511          "tracer-min-branch-probability",
 512          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available.",
 513          50, 0, 100)
 514
 515 /* The maximum number of incoming edges to consider for crossjumping.  */
 516 DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
 517          "max-crossjump-edges",
 518          "The maximum number of incoming edges to consider for crossjumping.",
 519          100, 0, 0)
 520
 521 /* The minimum number of matching instructions to consider for crossjumping.  */
 522 DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS,
 523      "min-crossjump-insns",
 524      "The minimum number of matching instructions to consider for crossjumping.",
 525      5, 1, 0)
 526
 527 /* The maximum number expansion factor when copying basic blocks.  */
 528 DEFPARAM(PARAM_MAX_GROW_COPY_BB_INSNS,
 529      "max-grow-copy-bb-insns",
 530      "The maximum expansion factor when copying basic blocks.",
 531      8, 0, 0)
 532
 533 /* The maximum number of insns to duplicate when unfactoring computed gotos.  */
 534 DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS,
 535      "max-goto-duplication-insns",
 536      "The maximum number of insns to duplicate when unfactoring computed gotos.",
 537      8, 0, 0)
 538
 539 /* The maximum length of path considered in cse.  */
 540 DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
 541          "max-cse-path-length",
 542          "The maximum length of path considered in cse.",
 543          10, 1, 0)
 544 DEFPARAM(PARAM_MAX_CSE_INSNS,
 545          "max-cse-insns",
 546          "The maximum instructions CSE process before flushing.",
 547          1000, 0, 0)
 548
 549 /* The cost of expression in loop invariant motion that is considered
 550    expensive.  */
 551 DEFPARAM(PARAM_LIM_EXPENSIVE,
 552          "lim-expensive",
 553          "The minimum cost of an expensive expression in the loop invariant motion.",
 554          20, 0, 0)
 555
 556 /* Bound on number of candidates for induction variables below that
 557    all candidates are considered for each use in induction variable
 558    optimizations.  */
 559
 560 DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND,
 561          "iv-consider-all-candidates-bound",
 562          "Bound on number of candidates below that all candidates are considered in iv optimizations.",
 563          40, 0, 0)
 564
 565 /* The induction variable optimizations give up on loops that contain more
 566    induction variable uses.  */
 567
 568 DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES,
 569          "iv-max-considered-uses",
 570          "Bound on number of iv uses in loop optimized in iv optimizations.",
 571          250, 0, 0)
 572
 573 /* If there are at most this number of ivs in the set, try removing unnecessary
 574    ivs from the set always.  */
 575
 576 DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND,
 577          "iv-always-prune-cand-set-bound",
 578          "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization.",
 579          10, 0, 0)
 580
 581 DEFPARAM(PARAM_AVG_LOOP_NITER,
 582          "avg-loop-niter",
 583          "Average number of iterations of a loop.",
 584          10, 1, 0)
 585
 586 DEFPARAM(PARAM_DSE_MAX_OBJECT_SIZE,
 587          "dse-max-object-size",
 588          "Maximum size (in bytes) of objects tracked bytewise by dead store elimination.",
 589          256, 0, 0)
 590
 591 DEFPARAM(PARAM_DSE_MAX_ALIAS_QUERIES_PER_STORE,
 592          "dse-max-alias-queries-per-store",
 593          "Maximum number of queries into the alias oracle per store.",
 594          256, 0, 0)
 595
 596 DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE,
 597          "scev-max-expr-size",
 598          "Bound on size of expressions used in the scalar evolutions analyzer.",
 599          100, 0, 0)
 600
 601 DEFPARAM(PARAM_SCEV_MAX_EXPR_COMPLEXITY,
 602          "scev-max-expr-complexity",
 603          "Bound on the complexity of the expressions in the scalar evolutions analyzer.",
 604          10, 0, 0)
 605
 606 DEFPARAM (PARAM_MAX_TREE_IF_CONVERSION_PHI_ARGS,
 607           "max-tree-if-conversion-phi-args",
 608           "Maximum number of arguments in a PHI supported by TREE if-conversion "
 609           "unless the loop is marked with simd pragma.",
 610           4, 2, 0)
 611
 612 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIGNMENT_CHECKS,
 613          "vect-max-version-for-alignment-checks",
 614          "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alignment check.",
 615          6, 0, 0)
 616
 617 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS,
 618          "vect-max-version-for-alias-checks",
 619          "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alias check.",
 620          10, 0, 0)
 621
 622 DEFPARAM(PARAM_VECT_MAX_PEELING_FOR_ALIGNMENT,
 623          "vect-max-peeling-for-alignment",
 624          "Maximum number of loop peels to enhance alignment of data references in a loop.",
 625          -1, -1, 64)
 626
 627 DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS,
 628          "max-cselib-memory-locations",
 629          "The maximum memory locations recorded by cselib.",
 630          500, 0, 0)
 631
 632 #ifdef ENABLE_GC_ALWAYS_COLLECT
 633 # define GGC_MIN_EXPAND_DEFAULT 0
 634 # define GGC_MIN_HEAPSIZE_DEFAULT 0
 635 #else
 636 # define GGC_MIN_EXPAND_DEFAULT 30
 637 # define GGC_MIN_HEAPSIZE_DEFAULT 4096
 638 #endif
 639
 640 DEFPARAM(GGC_MIN_EXPAND,
 641          "ggc-min-expand",
 642          "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap.",
 643          GGC_MIN_EXPAND_DEFAULT, 0, 0)
 644
 645 DEFPARAM(GGC_MIN_HEAPSIZE,
 646          "ggc-min-heapsize",
 647          "Minimum heap size before we start collecting garbage, in kilobytes.",
 648          GGC_MIN_HEAPSIZE_DEFAULT, 0, 0)
 649
 650 #undef GGC_MIN_EXPAND_DEFAULT
 651 #undef GGC_MIN_HEAPSIZE_DEFAULT
 652
 653 DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
 654          "max-reload-search-insns",
 655          "The maximum number of instructions to search backward when looking for equivalent reload.",
 656          100, 0, 0)
 657
 658 DEFPARAM(PARAM_SINK_FREQUENCY_THRESHOLD,
 659          "sink-frequency-threshold",
 660          "Target block's relative execution frequency (as a percentage) required to sink a statement.",
 661          75, 0, 100)
 662
 663 DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS,
 664          "max-sched-region-blocks",
 665          "The maximum number of blocks in a region to be considered for interblock scheduling.",
 666          10, 0, 0)
 667
 668 DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS,
 669          "max-sched-region-insns",
 670          "The maximum number of insns in a region to be considered for interblock scheduling.",
 671          100, 0, 0)
 672
 673 DEFPARAM(PARAM_MAX_PIPELINE_REGION_BLOCKS,
 674          "max-pipeline-region-blocks",
 675          "The maximum number of blocks in a region to be considered for interblock scheduling.",
 676          15, 0, 0)
 677
 678 DEFPARAM(PARAM_MAX_PIPELINE_REGION_INSNS,
 679          "max-pipeline-region-insns",
 680          "The maximum number of insns in a region to be considered for interblock scheduling.",
 681          200, 0, 0)
 682
 683 DEFPARAM(PARAM_MIN_SPEC_PROB,
 684          "min-spec-prob",
 685          "The minimum probability of reaching a source block for interblock speculative scheduling.",
 686          40, 0, 0)
 687
 688 DEFPARAM(PARAM_MAX_SCHED_EXTEND_REGIONS_ITERS,
 689          "max-sched-extend-regions-iters",
 690          "The maximum number of iterations through CFG to extend regions.",
 691          0, 0, 0)
 692
 693 DEFPARAM(PARAM_MAX_SCHED_INSN_CONFLICT_DELAY,
 694          "max-sched-insn-conflict-delay",
 695          "The maximum conflict delay for an insn to be considered for speculative motion.",
 696          3, 1, 10)
 697
 698 DEFPARAM(PARAM_SCHED_SPEC_PROB_CUTOFF,
 699          "sched-spec-prob-cutoff",
 700          "The minimal probability of speculation success (in percents), so that speculative insn will be scheduled.",
 701          40, 0, 100)
 702
 703 DEFPARAM(PARAM_SCHED_STATE_EDGE_PROB_CUTOFF,
 704          "sched-state-edge-prob-cutoff",
 705          "The minimum probability an edge must have for the scheduler to save its state across it.",
 706          10, 0, 100)
 707
 708 DEFPARAM(PARAM_SELSCHED_MAX_LOOKAHEAD,
 709          "selsched-max-lookahead",
 710          "The maximum size of the lookahead window of selective scheduling.",
 711          50, 0, 0)
 712
 713 DEFPARAM(PARAM_SELSCHED_MAX_SCHED_TIMES,
 714          "selsched-max-sched-times",
 715          "Maximum number of times that an insn could be scheduled.",
 716          2, 1, 0)
 717
 718 DEFPARAM(PARAM_SELSCHED_INSNS_TO_RENAME,
 719          "selsched-insns-to-rename",
 720          "Maximum number of instructions in the ready list that are considered eligible for renaming.",
 721          2, 0, 0)
 722
 723 DEFPARAM (PARAM_SCHED_MEM_TRUE_DEP_COST,
 724           "sched-mem-true-dep-cost",
 725           "Minimal distance between possibly conflicting store and load.",
 726           1, 0, 0)
 727
 728 DEFPARAM (PARAM_SCHED_AUTOPREF_QUEUE_DEPTH,
 729           "sched-autopref-queue-depth",
 730           "Hardware autoprefetcher scheduler model control flag.  Number of lookahead cycles the model looks into; at '0' only enable instruction sorting heuristic.  Disabled by default.",
 731           -1, 0, 0)
 732
 733 DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
 734          "max-last-value-rtl",
 735          "The maximum number of RTL nodes that can be recorded as combiner's last value.",
 736          10000, 0, 0)
 737
 738 DEFPARAM(PARAM_MAX_COMBINE_INSNS,
 739          "max-combine-insns",
 740          "The maximum number of insns combine tries to combine.",
 741          4, 2, 4)
 742
 743 /* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
 744    {signed,unsigned} integral types.  This determines N.
 745    Experimentation shows 251 to be a good value that generates the
 746    least amount of garbage for allocating the TREE_VEC storage.  */
 747 DEFPARAM (PARAM_INTEGER_SHARE_LIMIT,
 748           "integer-share-limit",
 749           "The upper bound for sharing integer constants.",
 750           251, 2, 2)
 751
 752 DEFPARAM (PARAM_SSP_BUFFER_SIZE,
 753           "ssp-buffer-size",
 754           "The lower bound for a buffer to be considered for stack smashing protection.",
 755           8, 1, 0)
 756
 757 DEFPARAM (PARAM_MIN_SIZE_FOR_STACK_SHARING,
 758           "min-size-for-stack-sharing",
 759           "The minimum size of variables taking part in stack slot sharing "
 760           "when not optimizing.",
 761           32, 0, 0)
 762
 763 /* When we thread through a block we have to make copies of the
 764    statements within the block.  Clearly for large blocks the code
 765    duplication is bad.
 766
 767    PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number
 768    of statements and PHI nodes allowed in a block which is going to
 769    be duplicated for thread jumping purposes.
 770
 771    Some simple analysis showed that more than 99% of the jump
 772    threading opportunities are for blocks with less than 15
 773    statements.  So we can get the benefits of jump threading
 774    without excessive code bloat for pathological cases with the
 775    throttle set at 15 statements.  */
 776 DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS,
 777           "max-jump-thread-duplication-stmts",
 778           "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps.",
 779           15, 0, 0)
 780
 781 /* This is the maximum number of fields a variable may have before the pointer analysis machinery
 782    will stop trying to treat it in a field-sensitive manner.
 783    There are programs out there with thousands of fields per structure, and handling them
 784    field-sensitively is not worth the cost.  */
 785 DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE,
 786           "max-fields-for-field-sensitive",
 787           "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable.",
 788           0, 0, 0)
 789
 790 DEFPARAM(PARAM_MAX_SCHED_READY_INSNS,
 791          "max-sched-ready-insns",
 792          "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass.",
 793          100, 1, 0)
 794
 795 /* This is the maximum number of active local stores RTL DSE will consider.  */
 796 DEFPARAM (PARAM_MAX_DSE_ACTIVE_LOCAL_STORES,
 797           "max-dse-active-local-stores",
 798           "Maximum number of active local stores in RTL dead store elimination.",
 799           5000, 0, 0)
 800
 801 /* Prefetching and cache-optimizations related parameters.  Default values are
 802    usually set by machine description.  */
 803
 804 /* The number of insns executed before prefetch is completed.  */
 805
 806 DEFPARAM (PARAM_PREFETCH_LATENCY,
 807          "prefetch-latency",
 808          "The number of insns executed before prefetch is completed.",
 809          200, 0, 0)
 810
 811 /* The number of prefetches that can run at the same time.  */
 812
 813 DEFPARAM (PARAM_SIMULTANEOUS_PREFETCHES,
 814           "simultaneous-prefetches",
 815           "The number of prefetches that can run at the same time.",
 816           3, 0, 0)
 817
 818 /* The size of L1 cache in kB.  */
 819
 820 DEFPARAM (PARAM_L1_CACHE_SIZE,
 821           "l1-cache-size",
 822           "The size of L1 cache.",
 823           64, 0, 0)
 824
 825 /* The size of L1 cache line in bytes.  */
 826
 827 DEFPARAM (PARAM_L1_CACHE_LINE_SIZE,
 828           "l1-cache-line-size",
 829           "The size of L1 cache line.",
 830           32, 0, 0)
 831
 832 /* The size of L2 cache in kB.  */
 833
 834 DEFPARAM (PARAM_L2_CACHE_SIZE,
 835           "l2-cache-size",
 836           "The size of L2 cache.",
 837           512, 0, 0)
 838
 839 /* Whether software prefetch hints should be issued for non-constant
 840    strides.  */
 841
 842 DEFPARAM (PARAM_PREFETCH_DYNAMIC_STRIDES,
 843           "prefetch-dynamic-strides",
 844           "Whether software prefetch hints should be issued for non-constant "
 845           "strides.",
 846           1, 0, 1)
 847
 848 /* The minimum constant stride beyond which we should use prefetch hints
 849    for.  */
 850
 851 DEFPARAM (PARAM_PREFETCH_MINIMUM_STRIDE,
 852           "prefetch-minimum-stride",
 853           "The minimum constant stride beyond which we should use prefetch "
 854           "hints for.",
 855           -1, 0, 0)
 856
 857 /* Maximum number of statements in loop nest for loop interchange.  */
 858
 859 DEFPARAM (PARAM_LOOP_INTERCHANGE_MAX_NUM_STMTS,
 860           "loop-interchange-max-num-stmts",
 861           "The maximum number of stmts in loop nest for loop interchange.",
 862           64, 0, 0)
 863
 864 /* Minimum stride ratio for loop interchange to be profitiable.  */
 865
 866 DEFPARAM (PARAM_LOOP_INTERCHANGE_STRIDE_RATIO,
 867           "loop-interchange-stride-ratio",
 868           "The minimum stride ratio for loop interchange to be profitable.",
 869           2, 0, 0)
 870
 871 /* Whether we should use canonical types rather than deep "structural"
 872    type checking.  Setting this value to 1 (the default) improves
 873    compilation performance in the C++ and Objective-C++ front end;
 874    this value should only be set to zero to work around bugs in the
 875    canonical type system by disabling it.  */
 876
 877 DEFPARAM (PARAM_USE_CANONICAL_TYPES,
 878           "use-canonical-types",
 879           "Whether to use canonical types.",
 880           1, 0, 1)
 881
 882 DEFPARAM (PARAM_MAX_PARTIAL_ANTIC_LENGTH,
 883           "max-partial-antic-length",
 884           "Maximum length of partial antic set when performing tree pre optimization.",
 885           100, 0, 0)
 886
 887 /* The following is used as a stop-gap limit for cases where really deep
 888    loop nests cause compile-time to blow up.  If we hit this limit,
 889    FRE and PRE will value-number outer loops (but the outermost) in a
 890    loop nest non-optimistically.  */
 891
 892 DEFPARAM (PARAM_RPO_VN_MAX_LOOP_DEPTH,
 893           "rpo-vn-max-loop-depth",
 894           "Maximum depth of a loop nest to fully value-number optimistically.",
 895           7, 2, 0)
 896
 897 /* The following is used as a stop-gap limit for cases where really huge
 898    functions blow up compile-time use too much.  It limits the number of
 899    alias-queries we do for finding common subexpressions for memory loads and
 900    stores.  The number of alias-queries is otherwise limited by the number of
 901    stores on paths to function entry.  */
 902
 903 DEFPARAM (PARAM_SCCVN_MAX_ALIAS_QUERIES_PER_ACCESS,
 904           "sccvn-max-alias-queries-per-access",
 905           "Maximum number of disambiguations to perform per memory access.",
 906           1000, 0, 0)
 907
 908 DEFPARAM (PARAM_IRA_MAX_LOOPS_NUM,
 909           "ira-max-loops-num",
 910           "Max loops number for regional RA.",
 911           100, 0, 0)
 912
 913 DEFPARAM (PARAM_IRA_MAX_CONFLICT_TABLE_SIZE,
 914           "ira-max-conflict-table-size",
 915           "Max size of conflict table in MB.",
 916           1000, 0, 0)
 917
 918 DEFPARAM (PARAM_IRA_LOOP_RESERVED_REGS,
 919           "ira-loop-reserved-regs",
 920           "The number of registers in each class kept unused by loop invariant motion.",
 921           2, 0, 0)
 922
 923 DEFPARAM (PARAM_LRA_MAX_CONSIDERED_RELOAD_PSEUDOS,
 924           "lra-max-considered-reload-pseudos",
 925           "The max number of reload pseudos which are considered during spilling a non-reload pseudo.",
 926           500, 0, 0)
 927
 928 DEFPARAM (PARAM_LRA_INHERITANCE_EBB_PROBABILITY_CUTOFF,
 929           "lra-inheritance-ebb-probability-cutoff",
 930           "Minimal fall-through edge probability in percentage used to add BB to inheritance EBB in LRA.",
 931           40, 0, 100)
 932
 933 /* Switch initialization conversion will refuse to create arrays that are
 934    bigger than this parameter times the number of switch branches.  */
 935
 936 DEFPARAM (PARAM_SWITCH_CONVERSION_BRANCH_RATIO,
 937           "switch-conversion-max-branch-ratio",
 938           "The maximum ratio between array size and switch branches for "
 939           "a switch conversion to take place.",
 940           8, 1, 0)
 941
 942 /* Size of tiles when doing loop blocking.  */
 943
 944 DEFPARAM (PARAM_LOOP_BLOCK_TILE_SIZE,
 945           "loop-block-tile-size",
 946           "Size of tiles for loop blocking.",
 947           51, 0, 0)
 948
 949 /* Maximal number of parameters that we allow in a SCoP.  */
 950
 951 DEFPARAM (PARAM_GRAPHITE_MAX_NB_SCOP_PARAMS,
 952           "graphite-max-nb-scop-params",
 953           "Maximum number of parameters in a SCoP.",
 954           10, 0, 0)
 955
 956 /* Maximal number of array references in a scop.  */
 957
 958 DEFPARAM (PARAM_GRAPHITE_MAX_ARRAYS_PER_SCOP,
 959           "graphite-max-arrays-per-scop",
 960           "Maximum number of arrays per SCoP.",
 961           100, 0, 0)
 962
 963 DEFPARAM (PARAM_MAX_ISL_OPERATIONS,
 964           "max-isl-operations",
 965           "Maximum number of isl operations, 0 means unlimited.",
 966           350000, 0, 0)
 967
 968 /* For testsuite purposes allow to check for codegen error handling.  */
 969 DEFPARAM (PARAM_GRAPHITE_ALLOW_CODEGEN_ERRORS,
 970           "graphite-allow-codegen-errors",
 971           "Whether codegen errors should be ICEs when -fchecking.",
 972           0, 0, 1)
 973
 974 /* Avoid data dependence analysis on very large loops.  */
 975 DEFPARAM (PARAM_LOOP_MAX_DATAREFS_FOR_DATADEPS,
 976           "loop-max-datarefs-for-datadeps",
 977           "Maximum number of datarefs in loop for building loop data dependencies.",
 978           1000, 0, 0)
 979
 980 /* Avoid doing loop invariant motion on very large loops.  */
 981
 982 DEFPARAM (PARAM_LOOP_INVARIANT_MAX_BBS_IN_LOOP,
 983           "loop-invariant-max-bbs-in-loop",
 984           "Max basic blocks number in loop for loop invariant motion.",
 985           10000, 0, 0)
 986
 987 /* When the parameter is 1, use the internal function id
 988    to look up for profile data. Otherwise, use a more stable
 989    external id based on assembler name and source location. */
 990 DEFPARAM (PARAM_PROFILE_FUNC_INTERNAL_ID,
 991           "profile-func-internal-id",
 992           "Use internal function id in profile lookup.",
 993           0, 0, 1)
 994
 995 /* When the parameter is 1, track the most frequent N target
 996    addresses in indirect-call profile. This disables
 997    indirect_call_profiler_v3 which tracks single target.  */
 998 DEFPARAM (PARAM_INDIR_CALL_TOPN_PROFILE,
 999           "indir-call-topn-profile",
1000           "Track top N target addresses in indirect-call profile.",
1001           0, 0, 1)
1002
1003 /* Avoid SLP vectorization of large basic blocks.  */
1004 DEFPARAM (PARAM_SLP_MAX_INSNS_IN_BB,
1005           "slp-max-insns-in-bb",
1006           "Maximum number of instructions in basic block to be considered for "
1007           "SLP vectorization.", 1000, 0, 0)
1008
1009 DEFPARAM (PARAM_MIN_INSN_TO_PREFETCH_RATIO,
1010           "min-insn-to-prefetch-ratio",
1011           "Min. ratio of insns to prefetches to enable prefetching for "
1012           "a loop with an unknown trip count.",
1013           9, 0, 0)
1014
1015 DEFPARAM (PARAM_PREFETCH_MIN_INSN_TO_MEM_RATIO,
1016           "prefetch-min-insn-to-mem-ratio",
1017           "Min. ratio of insns to mem ops to enable prefetching in a loop.",
1018           3, 0, 0)
1019
1020 /* Set maximum hash table size for var tracking.  */
1021
1022 DEFPARAM (PARAM_MAX_VARTRACK_SIZE,
1023           "max-vartrack-size",
1024           "Max. size of var tracking hash tables.",
1025           50000000, 0, 0)
1026
1027 /* Set maximum recursion depth for var tracking expression expansion
1028    and resolution.  */
1029
1030 DEFPARAM (PARAM_MAX_VARTRACK_EXPR_DEPTH,
1031           "max-vartrack-expr-depth",
1032           "Max. recursion depth for expanding var tracking expressions.",
1033           12, 0, 0)
1034
1035 /* Set maximum length of value location list for which var tracking
1036    should add reverse operations.  */
1037
1038 DEFPARAM (PARAM_MAX_VARTRACK_REVERSE_OP_SIZE,
1039           "max-vartrack-reverse-op-size",
1040           "Max. size of loc list for which reverse ops should be added.",
1041           50, 0, 0)
1042
1043 /* Set a threshold to discard debug markers (e.g. debug begin stmt
1044    markers) when expanding a function to RTL, or inlining it into
1045    another function.  */
1046
1047 DEFPARAM (PARAM_MAX_DEBUG_MARKER_COUNT,
1048           "max-debug-marker-count",
1049           "Max. count of debug markers to expand or inline.",
1050           100000, 0, 0)
1051
1052 /* Set minimum insn uid for non-debug insns.  */
1053
1054 DEFPARAM (PARAM_MIN_NONDEBUG_INSN_UID,
1055           "min-nondebug-insn-uid",
1056           "The minimum UID to be used for a nondebug insn.",
1057           0, 0, 0)
1058
1059 DEFPARAM (PARAM_IPA_SRA_PTR_GROWTH_FACTOR,
1060           "ipa-sra-ptr-growth-factor",
1061           "Maximum allowed growth of number and total size of new parameters "
1062           "that ipa-sra replaces a pointer to an aggregate with.",
1063           2, 0, 0)
1064
1065 DEFPARAM (PARAM_TM_MAX_AGGREGATE_SIZE,
1066           "tm-max-aggregate-size",
1067           "Size in bytes after which thread-local aggregates should be "
1068           "instrumented with the logging functions instead of save/restore "
1069           "pairs.",
1070           9, 0, 0)
1071
1072 DEFPARAM (PARAM_SRA_MAX_SCALARIZATION_SIZE_SPEED,
1073           "sra-max-scalarization-size-Ospeed",
1074           "Maximum size, in storage units, of an aggregate which should be "
1075           "considered for scalarization when compiling for speed.",
1076           0, 0, 0)
1077
1078 DEFPARAM (PARAM_SRA_MAX_SCALARIZATION_SIZE_SIZE,
1079           "sra-max-scalarization-size-Osize",
1080           "Maximum size, in storage units, of an aggregate which should be "
1081           "considered for scalarization when compiling for size.",
1082           0, 0, 0)
1083
1084 DEFPARAM (PARAM_IPA_CP_VALUE_LIST_SIZE,
1085           "ipa-cp-value-list-size",
1086           "Maximum size of a list of values associated with each parameter for "
1087           "interprocedural constant propagation.",
1088           8, 0, 0)
1089
1090 DEFPARAM (PARAM_IPA_CP_EVAL_THRESHOLD,
1091           "ipa-cp-eval-threshold",
1092           "Threshold ipa-cp opportunity evaluation that is still considered "
1093           "beneficial to clone.",
1094           500, 0, 0)
1095
1096 DEFPARAM (PARAM_IPA_CP_RECURSION_PENALTY,
1097           "ipa-cp-recursion-penalty",
1098           "Percentage penalty the recursive functions will receive when they "
1099           "are evaluated for cloning.",
1100           40, 0, 100)
1101
1102 DEFPARAM (PARAM_IPA_CP_SINGLE_CALL_PENALTY,
1103           "ipa-cp-single-call-penalty",
1104           "Percentage penalty functions containing a single call to another "
1105           "function will receive when they are evaluated for cloning.",
1106           15, 0, 100)
1107
1108 DEFPARAM (PARAM_IPA_MAX_AGG_ITEMS,
1109           "ipa-max-agg-items",
1110           "Maximum number of aggregate content items for a parameter in "
1111           "jump functions and lattices.",
1112           16, 0, 0)
1113
1114 DEFPARAM (PARAM_IPA_CP_LOOP_HINT_BONUS,
1115           "ipa-cp-loop-hint-bonus",
1116           "Compile-time bonus IPA-CP assigns to candidates which make loop "
1117           "bounds or strides known.",
1118           64, 0, 0)
1119
1120 DEFPARAM (PARAM_IPA_CP_ARRAY_INDEX_HINT_BONUS,
1121           "ipa-cp-array-index-hint-bonus",
1122           "Compile-time bonus IPA-CP assigns to candidates which make an array "
1123           "index known.",
1124           48, 0, 0)
1125
1126 DEFPARAM (PARAM_IPA_MAX_AA_STEPS,
1127           "ipa-max-aa-steps",
1128           "Maximum number of statements that will be visited by IPA formal "
1129           "parameter analysis based on alias analysis in any given function.",
1130           25000, 0, 0)
1131
1132 /* WHOPR partitioning configuration.  */
1133
1134 DEFPARAM (PARAM_LTO_PARTITIONS,
1135           "lto-partitions",
1136           "Number of partitions the program should be split to.",
1137           128, 1, 0)
1138
1139 DEFPARAM (MIN_PARTITION_SIZE,
1140           "lto-min-partition",
1141           "Minimal size of a partition for LTO (in estimated instructions).",
1142           10000, 0, 0)
1143
1144 DEFPARAM (MAX_PARTITION_SIZE,
1145           "lto-max-partition",
1146           "Maximal size of a partition for LTO (in estimated instructions).",
1147           1000000, 0, INT_MAX)
1148
1149 DEFPARAM (PARAM_MAX_LTO_STREAMING_PARALLELISM,
1150           "lto-max-streaming-parallelism",
1151           "maximal number of LTO partitions streamed in parallel.",
1152           32, 1, 0)
1153
1154 /* Diagnostic parameters.  */
1155
1156 DEFPARAM (CXX_MAX_NAMESPACES_FOR_DIAGNOSTIC_HELP,
1157           "cxx-max-namespaces-for-diagnostic-help",
1158           "Maximum number of namespaces to search for alternatives when "
1159           "name lookup fails.",
1160           1000, 0, 0)
1161
1162 /* Maximum number of conditional store pairs that can be sunk.  */
1163 DEFPARAM (PARAM_MAX_STORES_TO_SINK,
1164           "max-stores-to-sink",
1165           "Maximum number of conditional store pairs that can be sunk.",
1166           2, 0, 0)
1167
1168 /* Override CASE_VALUES_THRESHOLD of when to switch from doing switch
1169    statements via if statements to using a table jump operation.  If the value
1170    is 0, the default CASE_VALUES_THRESHOLD will be used.  */
1171 DEFPARAM (PARAM_CASE_VALUES_THRESHOLD,
1172           "case-values-threshold",
1173           "The smallest number of different values for which it is best to "
1174           "use a jump-table instead of a tree of conditional branches, "
1175           "if 0, use the default for the machine.",
1176           0, 0, 0)
1177
1178 /* Data race flags for C++0x memory model compliance.  */
1179 DEFPARAM (PARAM_ALLOW_STORE_DATA_RACES,
1180           "allow-store-data-races",
1181           "Allow new data races on stores to be introduced.",
1182           0, 0, 1)
1183
1184 /* Reassociation width to be used by tree reassoc optimization.  */
1185 DEFPARAM (PARAM_TREE_REASSOC_WIDTH,
1186           "tree-reassoc-width",
1187           "Set the maximum number of instructions executed in parallel in "
1188           "reassociated tree.  If 0, use the target dependent heuristic.",
1189           0, 0, 0)
1190
1191 DEFPARAM (PARAM_MAX_TAIL_MERGE_COMPARISONS,
1192           "max-tail-merge-comparisons",
1193           "Maximum amount of similar bbs to compare a bb with.",
1194           10, 0, 0)
1195
1196 DEFPARAM (PARAM_STORE_MERGING_ALLOW_UNALIGNED,
1197           "store-merging-allow-unaligned",
1198           "Allow the store merging pass to introduce unaligned stores "
1199           "if it is legal to do so.",
1200           1, 0, 1)
1201
1202 DEFPARAM (PARAM_MAX_STORES_TO_MERGE,
1203           "max-stores-to-merge",
1204           "Maximum number of constant stores to merge in the "
1205           "store merging pass.",
1206           64, 2, 0)
1207
1208 DEFPARAM (PARAM_MAX_TAIL_MERGE_ITERATIONS,
1209           "max-tail-merge-iterations",
1210           "Maximum amount of iterations of the pass over a function.",
1211           2, 0, 0)
1212
1213 /* Maximum number of strings for which strlen optimization pass will
1214    track string lenths.  */
1215 DEFPARAM (PARAM_MAX_TRACKED_STRLENS,
1216           "max-tracked-strlens",
1217           "Maximum number of strings for which strlen optimization pass will "
1218           "track string lengths.",
1219           10000, 0, 0)
1220
1221 /* Keep this in sync with the sched_pressure_algorithm enum.  */
1222 DEFPARAM (PARAM_SCHED_PRESSURE_ALGORITHM,
1223           "sched-pressure-algorithm",
1224           "Which -fsched-pressure algorithm to apply.",
1225           1, 1, 2)
1226
1227 /* Maximum length of candidate scans in straight-line strength reduction.  */
1228 DEFPARAM (PARAM_MAX_SLSR_CANDIDATE_SCAN,
1229           "max-slsr-cand-scan",
1230           "Maximum length of candidate scans for straight-line "
1231           "strength reduction.",
1232           50, 1, 999999)
1233
1234 /* ASan stands for AddressSanitizer: https://github.com/google/sanitizers.  */
1235
1236 DEFPARAM (PARAM_ASAN_STACK,
1237          "asan-stack",
1238          "Enable asan stack protection.",
1239          1, 0, 1)
1240
1241 DEFPARAM (PARAM_ASAN_PROTECT_ALLOCAS,
1242         "asan-instrument-allocas",
1243         "Enable asan allocas/VLAs protection.",
1244         1, 0, 1)
1245
1246 DEFPARAM (PARAM_ASAN_GLOBALS,
1247          "asan-globals",
1248          "Enable asan globals protection.",
1249          1, 0, 1)
1250
1251 DEFPARAM (PARAM_ASAN_INSTRUMENT_WRITES,
1252          "asan-instrument-writes",
1253          "Enable asan store operations protection.",
1254          1, 0, 1)
1255
1256 DEFPARAM (PARAM_ASAN_INSTRUMENT_READS,
1257          "asan-instrument-reads",
1258          "Enable asan load operations protection.",
1259          1, 0, 1)
1260
1261 DEFPARAM (PARAM_ASAN_MEMINTRIN,
1262          "asan-memintrin",
1263          "Enable asan builtin functions protection.",
1264          1, 0, 1)
1265
1266 DEFPARAM (PARAM_ASAN_USE_AFTER_RETURN,
1267          "asan-use-after-return",
1268          "Enable asan detection of use-after-return bugs.",
1269          1, 0, 1)
1270
1271 DEFPARAM (PARAM_ASAN_INSTRUMENTATION_WITH_CALL_THRESHOLD,
1272          "asan-instrumentation-with-call-threshold",
1273          "Use callbacks instead of inline code if number of accesses "
1274          "in function becomes greater or equal to this number.",
1275          7000, 0, INT_MAX)
1276
1277 DEFPARAM (PARAM_USE_AFTER_SCOPE_DIRECT_EMISSION_THRESHOLD,
1278          "use-after-scope-direct-emission-threshold",
1279          "Use direct poisoning/unpoisoning instructions for variables "
1280          "smaller or equal to this number.",
1281          256, 0, INT_MAX)
1282
1283 DEFPARAM (PARAM_UNINIT_CONTROL_DEP_ATTEMPTS,
1284           "uninit-control-dep-attempts",
1285           "Maximum number of nested calls to search for control dependencies "
1286           "during uninitialized variable analysis.",
1287           1000, 1, 0)
1288
1289 DEFPARAM (PARAM_FSM_SCALE_PATH_STMTS,
1290           "fsm-scale-path-stmts",
1291           "Scale factor to apply to the number of statements in a threading path when comparing to the number of (scaled) blocks.",
1292           2, 1, 10)
1293
1294 DEFPARAM (PARAM_FSM_MAXIMUM_PHI_ARGUMENTS,
1295           "fsm-maximum-phi-arguments",
1296           "Maximum number of arguments a PHI may have before the FSM threader will not try to thread through its block.",
1297           100, 1, 999999)
1298
1299 DEFPARAM (PARAM_FSM_SCALE_PATH_BLOCKS,
1300           "fsm-scale-path-blocks",
1301           "Scale factor to apply to the number of blocks in a threading path when comparing to the number of (scaled) statements.",
1302           3, 1, 10)
1303
1304 DEFPARAM (PARAM_MAX_FSM_THREAD_PATH_INSNS,
1305           "max-fsm-thread-path-insns",
1306           "Maximum number of instructions to copy when duplicating blocks on a finite state automaton jump thread path.",
1307           100, 1, 999999)
1308
1309 DEFPARAM (PARAM_MAX_FSM_THREAD_LENGTH,
1310           "max-fsm-thread-length",
1311           "Maximum number of basic blocks on a finite state automaton jump thread path.",
1312           10, 1, 999999)
1313
1314 DEFPARAM (PARAM_MAX_FSM_THREAD_PATHS,
1315           "max-fsm-thread-paths",
1316           "Maximum number of new jump thread paths to create for a finite state automaton.",
1317           50, 1, 999999)
1318
1319 DEFPARAM (PARAM_PARLOOPS_CHUNK_SIZE,
1320           "parloops-chunk-size",
1321           "Chunk size of omp schedule for loops parallelized by parloops.",
1322           0, 0, 0)
1323
1324 DEFPARAMENUM5 (PARAM_PARLOOPS_SCHEDULE,
1325                "parloops-schedule",
1326                "Schedule type of omp schedule for loops parallelized by "
1327                "parloops (static, dynamic, guided, auto, runtime).",
1328                static,
1329                static, dynamic, guided, auto, runtime)
1330
1331 DEFPARAM (PARAM_PARLOOPS_MIN_PER_THREAD,
1332           "parloops-min-per-thread",
1333           "Minimum number of iterations per thread of an innermost "
1334           "parallelized loop.",
1335           100, 2, 0)
1336
1337 DEFPARAM (PARAM_MAX_SSA_NAME_QUERY_DEPTH,
1338           "max-ssa-name-query-depth",
1339           "Maximum recursion depth allowed when querying a property of an"
1340           " SSA name.",
1341           3, 1, 10)
1342
1343 DEFPARAM (PARAM_MAX_RTL_IF_CONVERSION_INSNS,
1344           "max-rtl-if-conversion-insns",
1345           "Maximum number of insns in a basic block to consider for RTL "
1346           "if-conversion.",
1347           10, 0, 99)
1348
1349 DEFPARAM (PARAM_MAX_RTL_IF_CONVERSION_PREDICTABLE_COST,
1350           "max-rtl-if-conversion-predictable-cost",
1351           "Maximum permissible cost for the sequence that would be "
1352           "generated by the RTL if-conversion pass for a branch that "
1353           "is considered predictable.",
1354           20, 0, 200)
1355
1356 DEFPARAM (PARAM_MAX_RTL_IF_CONVERSION_UNPREDICTABLE_COST,
1357           "max-rtl-if-conversion-unpredictable-cost",
1358           "Maximum permissible cost for the sequence that would be "
1359           "generated by the RTL if-conversion pass for a branch that "
1360           "is considered unpredictable.",
1361           40, 0, 200)
1362
1363 DEFPARAM (PARAM_HSA_GEN_DEBUG_STORES,
1364           "hsa-gen-debug-stores",
1365           "Level of hsa debug stores verbosity.",
1366           0, 0, 1)
1367
1368 DEFPARAM (PARAM_MAX_SPECULATIVE_DEVIRT_MAYDEFS,
1369           "max-speculative-devirt-maydefs",
1370           "Maximum number of may-defs visited when devirtualizing "
1371           "speculatively.", 50, 0, 0)
1372
1373 DEFPARAM (PARAM_MAX_VRP_SWITCH_ASSERTIONS,
1374           "max-vrp-switch-assertions",
1375           "Maximum number of assertions to add along the default "
1376           "edge of a switch statement during VRP.",
1377           10, 0, 0)
1378
1379 DEFPARAM (PARAM_VECT_EPILOGUES_NOMASK,
1380           "vect-epilogues-nomask",
1381           "Enable loop epilogue vectorization using smaller vector size.",
1382           0, 0, 1)
1383
1384 DEFPARAM(PARAM_UNROLL_JAM_MIN_PERCENT,
1385          "unroll-jam-min-percent",
1386          "Minimum percentage of memrefs that must go away for unroll-and-jam to be considered profitable.",
1387          1, 0, 100)
1388
1389 DEFPARAM(PARAM_UNROLL_JAM_MAX_UNROLL,
1390          "unroll-jam-max-unroll",
1391          "Maximum unroll factor for the unroll-and-jam transformation.",
1392          4, 0, 0)
1393
1394 DEFPARAM(PARAM_AVOID_FMA_MAX_BITS,
1395          "avoid-fma-max-bits",
1396          "Maximum number of bits for which we avoid creating FMAs.",
1397          0, 0, 512)
1398
1399 DEFPARAM(PARAM_LOGICAL_OP_NON_SHORT_CIRCUIT,
1400          "logical-op-non-short-circuit",
1401          "True if a non-short-circuit operation is optimal.",
1402          -1, -1, 1)
1403
1404 DEFPARAM(PARAM_LOOP_VERSIONING_MAX_INNER_INSNS,
1405          "loop-versioning-max-inner-insns",
1406          "The maximum number of instructions in an inner loop that is being"
1407          " considered for versioning.",
1408          200, 0, 0)
1409
1410 DEFPARAM(PARAM_LOOP_VERSIONING_MAX_OUTER_INSNS,
1411          "loop-versioning-max-outer-insns",
1412          "The maximum number of instructions in an outer loop that is being"
1413          " considered for versioning, on top of the instructions in inner"
1414          " loops.",
1415          100, 0, 0)
1416
1417 /*
1418
1419 Local variables:
1420 mode:c
1421 End:
1422 */