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    The default value is 400.
  62    Only functions marked inline (or methods defined in the class
  63    definition for C++) are affected by this.
  64    There are more restrictions to inlining: If inlined functions
  65    call other functions, the already inlined instructions are
  66    counted and once the recursive inline limit (see
  67    "max-inline-insns" parameter) is exceeded, the acceptable size
  68    gets decreased.  */
  69 DEFPARAM (PARAM_MAX_INLINE_INSNS_SINGLE,
  70           "max-inline-insns-single",
  71           "The maximum number of instructions in a single function eligible for inlining.",
  72           400, 0, 0)
  73
  74 /* The single function inlining limit for functions that are
  75    inlined by virtue of -finline-functions (-O3).
  76    This limit should be chosen to be below or equal to the limit
  77    that is applied to functions marked inlined (or defined in the
  78    class declaration in C++) given by the "max-inline-insns-single"
  79    parameter.
  80    The default value is 30.  */
  81 DEFPARAM (PARAM_MAX_INLINE_INSNS_AUTO,
  82           "max-inline-insns-auto",
  83           "The maximum number of instructions when automatically inlining.",
  84           30, 0, 0)
  85
  86 DEFPARAM (PARAM_MAX_INLINE_INSNS_SMALL,
  87           "max-inline-insns-small",
  88           "The maximum number of instructions when automatically inlining small functions.",
  89           0, 0, 0)
  90
  91 DEFPARAM (PARAM_MAX_INLINE_INSNS_SIZE,
  92           "max-inline-insns-size",
  93           "The maximum number of instructions when inlining for size.",
  94           0, 0, 0)
  95
  96 DEFPARAM (PARAM_UNINLINED_FUNCTION_INSNS,
  97           "uninlined-function-insns",
  98           "Instruction accounted for function prologue, epilogue and other"
  99           " overhead.",
 100           2, 0, 0)
 101
 102 DEFPARAM (PARAM_UNINLINED_FUNCTION_TIME,
 103           "uninlined-function-time",
 104           "Time accounted for function prologue, epilogue and other"
 105           " overhead.",
 106           0, 0, 0)
 107
 108 DEFPARAM (PARAM_UNINLINED_FUNCTION_THUNK_INSNS,
 109           "uninlined-thunk-insns",
 110           "Instruction accounted for function thunk overhead.",
 111           2, 0, 0)
 112
 113 DEFPARAM (PARAM_UNINLINED_FUNCTION_THUNK_TIME,
 114           "uninlined-thunk-time",
 115           "Time accounted for function thunk overhead.",
 116           2, 0, 0)
 117
 118 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE,
 119           "max-inline-insns-recursive",
 120           "The maximum number of instructions inline function can grow to via recursive inlining.",
 121           450, 0, 0)
 122
 123 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO,
 124           "max-inline-insns-recursive-auto",
 125           "The maximum number of instructions non-inline function can grow to via recursive inlining.",
 126           450, 0, 0)
 127
 128 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH,
 129           "max-inline-recursive-depth",
 130           "The maximum depth of recursive inlining for inline functions.",
 131           8, 0, 0)
 132
 133 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO,
 134           "max-inline-recursive-depth-auto",
 135           "The maximum depth of recursive inlining for non-inline functions.",
 136           8, 0, 0)
 137
 138 DEFPARAM (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY,
 139           "min-inline-recursive-probability",
 140           "Inline recursively only when the probability of call being executed exceeds the parameter.",
 141           10, 0, 0)
 142
 143 /* Limit of iterations of early inliner.  This basically bounds number of
 144    nested indirect calls early inliner can resolve.  Deeper chains are still
 145    handled by late inlining.  */
 146 DEFPARAM (PARAM_EARLY_INLINER_MAX_ITERATIONS,
 147           "max-early-inliner-iterations",
 148           "The maximum number of nested indirect inlining performed by early inliner.",
 149           1, 0, 0)
 150
 151 /* Limit on probability of entry BB.  */
 152 DEFPARAM (PARAM_COMDAT_SHARING_PROBABILITY,
 153           "comdat-sharing-probability",
 154           "Probability that COMDAT function will be shared with different compilation unit.",
 155           20, 0, 0)
 156
 157 /* Limit on probability of entry BB.  */
 158 DEFPARAM (PARAM_PARTIAL_INLINING_ENTRY_PROBABILITY,
 159           "partial-inlining-entry-probability",
 160           "Maximum probability of the entry BB of split region (in percent relative to entry BB of the function) to make partial inlining happen.",
 161           70, 0, 100)
 162
 163 /* Limit the number of expansions created by the variable expansion
 164    optimization to avoid register pressure.  */
 165 DEFPARAM (PARAM_MAX_VARIABLE_EXPANSIONS,
 166           "max-variable-expansions-in-unroller",
 167           "If -fvariable-expansion-in-unroller is used, the maximum number of times that an individual variable will be expanded during loop unrolling.",
 168           1, 0, 0)
 169
 170 /* Limit loop autovectorization to loops with large enough iteration count.  */
 171 DEFPARAM (PARAM_MIN_VECT_LOOP_BOUND,
 172           "min-vect-loop-bound",
 173           "If -ftree-vectorize is used, the minimal loop bound of a loop to be considered for vectorization.",
 174           0, 0, 0)
 175
 176 /* The maximum number of instructions to consider when looking for an
 177    instruction to fill a delay slot.  If more than this arbitrary
 178    number of instructions is searched, the time savings from filling
 179    the delay slot will be minimal so stop searching.  Increasing
 180    values mean more aggressive optimization, making the compile time
 181    increase with probably small improvement in executable run time.  */
 182 DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH,
 183           "max-delay-slot-insn-search",
 184           "The maximum number of instructions to consider to fill a delay slot.",
 185           100, 0, 0)
 186
 187 /* When trying to fill delay slots, the maximum number of instructions
 188    to consider when searching for a block with valid live register
 189    information.  Increasing this arbitrarily chosen value means more
 190    aggressive optimization, increasing the compile time.  This
 191    parameter should be removed when the delay slot code is rewritten
 192    to maintain the control-flow graph.  */
 193 DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH,
 194          "max-delay-slot-live-search",
 195          "The maximum number of instructions to consider to find accurate live register information.",
 196          333, 0, 0)
 197
 198 /* This parameter limits the number of branch elements that the
 199    scheduler will track anti-dependencies through without resetting
 200    the tracking mechanism.  Large functions with few calls or barriers
 201    can generate lists containing many 1000's of dependencies.  Generally
 202    the compiler either uses all available memory, or runs for far too long.  */
 203 DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH,
 204          "max-pending-list-length",
 205          "The maximum length of scheduling's pending operations list.",
 206          32, 0, 0)
 207
 208 /* This parameter limits the number of backtracking attempts when using the
 209    haifa scheduler for modulo scheduling.  */
 210 DEFPARAM(PARAM_MAX_MODULO_BACKTRACK_ATTEMPTS,
 211          "max-modulo-backtrack-attempts",
 212          "The maximum number of backtrack attempts the scheduler should make when modulo scheduling a loop.",
 213          40, 0, 0)
 214
 215 DEFPARAM(PARAM_LARGE_FUNCTION_INSNS,
 216          "large-function-insns",
 217          "The size of function body to be considered large.",
 218          2700, 0, 0)
 219 DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH,
 220          "large-function-growth",
 221          "Maximal growth due to inlining of large function (in percent).",
 222          100, 0, 0)
 223 DEFPARAM(PARAM_LARGE_UNIT_INSNS,
 224          "large-unit-insns",
 225          "The size of translation unit to be considered large.",
 226          10000, 0, 0)
 227 DEFPARAM(PARAM_INLINE_UNIT_GROWTH,
 228          "inline-unit-growth",
 229          "How much can given compilation unit grow because of the inlining (in percent).",
 230          40, 0, 0)
 231 DEFPARAM(PARAM_IPCP_UNIT_GROWTH,
 232          "ipcp-unit-growth",
 233          "How much can given compilation unit grow because of the interprocedural constant propagation (in percent).",
 234          10, 0, 0)
 235 DEFPARAM(PARAM_EARLY_INLINING_INSNS,
 236          "early-inlining-insns",
 237          "Maximal estimated growth of function body caused by early inlining of single call.",
 238          14, 0, 0)
 239 DEFPARAM(PARAM_LARGE_STACK_FRAME,
 240          "large-stack-frame",
 241          "The size of stack frame to be considered large.",
 242          256, 0, 0)
 243 DEFPARAM(PARAM_STACK_FRAME_GROWTH,
 244          "large-stack-frame-growth",
 245          "Maximal stack frame growth due to inlining (in percent).",
 246          1000, 0, 0)
 247
 248 /* Keep these up to date with those in configure.ac.  */
 249 DEFPARAM(PARAM_STACK_CLASH_PROTECTION_GUARD_SIZE,
 250          "stack-clash-protection-guard-size",
 251          "Size of the stack guard expressed as a power of two in bytes.",
 252          12, 12, 30)
 253
 254 DEFPARAM(PARAM_STACK_CLASH_PROTECTION_PROBE_INTERVAL,
 255          "stack-clash-protection-probe-interval",
 256          "Interval in which to probe the stack expressed as a power of two in bytes.",
 257          12, 10, 16)
 258
 259 /* The GCSE optimization will be disabled if it would require
 260    significantly more memory than this value.  */
 261 DEFPARAM(PARAM_MAX_GCSE_MEMORY,
 262          "max-gcse-memory",
 263          "The maximum amount of memory to be allocated by GCSE.",
 264          128 * 1024 * 1024, 0, 0)
 265
 266 /* The GCSE optimization of an expression will avoided if the ratio of
 267    insertions to deletions is greater than this value.  */
 268 DEFPARAM(PARAM_MAX_GCSE_INSERTION_RATIO,
 269          "max-gcse-insertion-ratio",
 270          "The maximum ratio of insertions to deletions of expressions in GCSE.",
 271          20, 0, 0)
 272
 273 /* This is the threshold ratio when to perform partial redundancy
 274    elimination after reload. We perform partial redundancy elimination
 275    when the following holds:
 276    (Redundant load execution count)
 277    ------------------------------- >= GCSE_AFTER_RELOAD_PARTIAL_FRACTION
 278    (Added loads execution count)                                          */
 279 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_PARTIAL_FRACTION,
 280         "gcse-after-reload-partial-fraction",
 281         "The threshold ratio for performing partial redundancy elimination after reload.",
 282         3, 0, 0)
 283 /* This is the threshold ratio of the critical edges execution count compared to
 284    the redundant loads execution count that permits performing the load
 285    redundancy elimination in gcse after reload.  */
 286 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_CRITICAL_FRACTION,
 287         "gcse-after-reload-critical-fraction",
 288         "The threshold ratio of critical edges execution count that permit performing redundancy elimination after reload.",
 289         10, 0, 0)
 290
 291 /* GCSE will use GCSE_COST_DISTANCE_RATION as a scaling factor
 292    to calculate maximum distance for which an expression is allowed to move
 293    from its rtx_cost.  */
 294 DEFPARAM(PARAM_GCSE_COST_DISTANCE_RATIO,
 295          "gcse-cost-distance-ratio",
 296          "Scaling factor in calculation of maximum distance an expression can be moved by GCSE optimizations.",
 297          10, 0, 0)
 298 /* GCSE won't restrict distance for which an expression with rtx_cost greater
 299    than COSTS_N_INSN(GCSE_UNRESTRICTED_COST) is allowed to move.  */
 300 DEFPARAM(PARAM_GCSE_UNRESTRICTED_COST,
 301          "gcse-unrestricted-cost",
 302          "Cost at which GCSE optimizations will not constraint the distance an expression can travel.",
 303          3, 0, 0)
 304
 305 /* How deep from a given basic block the dominator tree should be searched
 306    for expressions to hoist to the block.  The value of 0 will avoid limiting
 307    the search.  */
 308 DEFPARAM(PARAM_MAX_HOIST_DEPTH,
 309          "max-hoist-depth",
 310          "Maximum depth of search in the dominator tree for expressions to hoist.",
 311          30, 0, 0)
 312
 313
 314 /* When synthesizing expnonentiation by a real constant operations using square
 315    roots, this controls how deep sqrt chains we are willing to generate.  */
 316 DEFPARAM(PARAM_MAX_POW_SQRT_DEPTH,
 317          "max-pow-sqrt-depth",
 318          "Maximum depth of sqrt chains to use when synthesizing exponentiation by a real constant.",
 319          5, 1, 32)
 320
 321 /* This parameter limits the number of insns in a loop that will be unrolled,
 322    and by how much the loop is unrolled.
 323
 324    This limit should be at most half of the peeling limits:  loop unroller
 325    decides to not unroll loops that iterate fewer than 2*number of allowed
 326    unrollings and thus we would have loops that are neither peeled or unrolled
 327    otherwise.  */
 328 DEFPARAM(PARAM_MAX_UNROLLED_INSNS,
 329          "max-unrolled-insns",
 330          "The maximum number of instructions to consider to unroll in a loop.",
 331          200, 0, 0)
 332 /* This parameter limits how many times the loop is unrolled depending
 333    on number of insns really executed in each iteration.  */
 334 DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS,
 335          "max-average-unrolled-insns",
 336          "The maximum number of instructions to consider to unroll in a loop on average.",
 337          80, 0, 0)
 338 /* The maximum number of unrollings of a single loop.  */
 339 DEFPARAM(PARAM_MAX_UNROLL_TIMES,
 340         "max-unroll-times",
 341         "The maximum number of unrollings of a single loop.",
 342         8, 0, 0)
 343 /* The maximum number of insns of a peeled loop.  */
 344 DEFPARAM(PARAM_MAX_PEELED_INSNS,
 345         "max-peeled-insns",
 346         "The maximum number of insns of a peeled loop.",
 347         100, 0, 0)
 348 /* The maximum number of peelings of a single loop.  */
 349 DEFPARAM(PARAM_MAX_PEEL_TIMES,
 350         "max-peel-times",
 351         "The maximum number of peelings of a single loop.",
 352         16, 0, 0)
 353 /* The maximum number of peelings of a single loop that is peeled completely.  */
 354 DEFPARAM(PARAM_MAX_PEEL_BRANCHES,
 355         "max-peel-branches",
 356         "The maximum number of branches on the path through the peeled sequence.",
 357         32, 0, 0)
 358 /* The maximum number of insns of a peeled loop.  */
 359 DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS,
 360         "max-completely-peeled-insns",
 361         "The maximum number of insns of a completely peeled loop.",
 362         200, 0, 0)
 363 /* The maximum number of peelings of a single loop that is peeled completely.  */
 364 DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES,
 365         "max-completely-peel-times",
 366         "The maximum number of peelings of a single loop that is peeled completely.",
 367         16, 0, 0)
 368 /* The maximum number of insns of a peeled loop that rolls only once.  */
 369 DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS,
 370         "max-once-peeled-insns",
 371         "The maximum number of insns of a peeled loop that rolls only once.",
 372         400, 0, 0)
 373 /* The maximum depth of a loop nest we completely peel.  */
 374 DEFPARAM(PARAM_MAX_UNROLL_ITERATIONS,
 375          "max-completely-peel-loop-nest-depth",
 376          "The maximum depth of a loop nest we completely peel.",
 377          8, 0, 0)
 378
 379 /* The maximum number of insns of an unswitched loop.  */
 380 DEFPARAM(PARAM_MAX_UNSWITCH_INSNS,
 381         "max-unswitch-insns",
 382         "The maximum number of insns of an unswitched loop.",
 383         50, 0, 0)
 384 /* The maximum level of recursion in unswitch_single_loop.  */
 385 DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL,
 386         "max-unswitch-level",
 387         "The maximum number of unswitchings in a single loop.",
 388         3, 0, 0)
 389
 390 /* The maximum number of insns in loop header duplicated by the copy loop
 391    headers pass.  */
 392 DEFPARAM(PARAM_MAX_LOOP_HEADER_INSNS,
 393         "max-loop-header-insns",
 394         "The maximum number of insns in loop header duplicated by the copy loop headers pass.",
 395         20, 0, 0)
 396
 397 /* The maximum number of iterations of a loop the brute force algorithm
 398    for analysis of # of iterations of the loop tries to evaluate.  */
 399 DEFPARAM(PARAM_MAX_ITERATIONS_TO_TRACK,
 400         "max-iterations-to-track",
 401         "Bound on the number of iterations the brute force # of iterations analysis algorithm evaluates.",
 402         1000, 0, 0)
 403 /* A cutoff to avoid costly computations of the number of iterations in
 404    the doloop transformation.  */
 405 DEFPARAM(PARAM_MAX_ITERATIONS_COMPUTATION_COST,
 406         "max-iterations-computation-cost",
 407         "Bound on the cost of an expression to compute the number of iterations.",
 408         10, 0, 0)
 409
 410 /* This parameter is used to tune SMS MAX II calculations.  */
 411 DEFPARAM(PARAM_SMS_MAX_II_FACTOR,
 412          "sms-max-ii-factor",
 413          "A factor for tuning the upper bound that swing modulo scheduler uses for scheduling a loop.",
 414          100, 0, 0)
 415 /* The minimum value of stage count that swing modulo scheduler will generate.  */
 416 DEFPARAM(PARAM_SMS_MIN_SC,
 417         "sms-min-sc",
 418         "The minimum value of stage count that swing modulo scheduler will generate.",
 419         2, 1, 1)
 420 DEFPARAM(PARAM_SMS_DFA_HISTORY,
 421          "sms-dfa-history",
 422          "The number of cycles the swing modulo scheduler considers when checking conflicts using DFA.",
 423          0, 0, 0)
 424 DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD,
 425          "sms-loop-average-count-threshold",
 426          "A threshold on the average loop count considered by the swing modulo scheduler.",
 427          0, 0, 0)
 428
 429 DEFPARAM(HOT_BB_COUNT_FRACTION,
 430          "hot-bb-count-fraction",
 431          "Select fraction of the maximal count of repetitions of basic block in program given basic "
 432          "block needs to have to be considered hot (used in non-LTO mode).",
 433          10000, 0, 0)
 434 DEFPARAM(HOT_BB_COUNT_WS_PERMILLE,
 435          "hot-bb-count-ws-permille",
 436          "A basic block profile count is considered hot if it contributes to "
 437          "the given permillage of the entire profiled execution (used in LTO mode).",
 438          990, 0, 1000)
 439 DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
 440          "hot-bb-frequency-fraction",
 441          "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot.",
 442          1000, 0, 0)
 443
 444 DEFPARAM(UNLIKELY_BB_COUNT_FRACTION,
 445          "unlikely-bb-count-fraction",
 446          "The minimum fraction of profile runs a given basic block execution count must be not to be considered unlikely.",
 447          20, 1, 10000)
 448
 449 DEFPARAM (PARAM_ALIGN_THRESHOLD,
 450           "align-threshold",
 451           "Select fraction of the maximal frequency of executions of basic block in function given basic block get alignment.",
 452           100, 1, 0)
 453
 454 DEFPARAM (PARAM_ALIGN_LOOP_ITERATIONS,
 455           "align-loop-iterations",
 456           "Loops iterating at least selected number of iterations will get "
 457           "loop alignment.", 4, 0, 0)
 458
 459 /* For guessed profiles, the loops having unknown number of iterations
 460    are predicted to iterate relatively few (10) times at average.
 461    For functions containing one loop with large known number of iterations
 462    and other loops having unbounded loops we would end up predicting all
 463    the other loops cold that is not usually the case.  So we need to artificially
 464    flatten the profile.
 465
 466    We need to cut the maximal predicted iterations to large enough iterations
 467    so the loop appears important, but safely within maximum hotness
 468    range.  */
 469
 470 DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS,
 471          "max-predicted-iterations",
 472          "The maximum number of loop iterations we predict statically.",
 473          100, 0, 0)
 474
 475 /* This parameter controls the probability of builtin_expect. The default
 476    value is 90%. This empirical value is obtained through the weighted
 477    probability of FDO counters (with the FDO count value as the weight)
 478    in some real world programs:
 479    (1) Google performance test benchmarks: the probability is 0.9081.
 480    (2) Linux 3.3 kernel running Google search workload: the probability
 481    is 0.8717.  */
 482
 483 DEFPARAM(BUILTIN_EXPECT_PROBABILITY,
 484          "builtin-expect-probability",
 485          "Set the estimated probability in percentage for builtin expect. The default value is 90% probability.",
 486          90, 0, 100)
 487 DEFPARAM(BUILTIN_STRING_CMP_INLINE_LENGTH,
 488          "builtin-string-cmp-inline-length",
 489          "The maximum length of a constant string for a builtin string cmp call eligible for inlining. The default value is 3.",
 490          3, 0, 100)
 491 DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
 492          "tracer-dynamic-coverage-feedback",
 493          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available.",
 494          95, 0, 100)
 495 DEFPARAM(TRACER_DYNAMIC_COVERAGE,
 496          "tracer-dynamic-coverage",
 497          "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available.",
 498          75, 0, 100)
 499 DEFPARAM(TRACER_MAX_CODE_GROWTH,
 500          "tracer-max-code-growth",
 501          "Maximal code growth caused by tail duplication (in percent).",
 502          100, 0, 0)
 503 DEFPARAM(TRACER_MIN_BRANCH_RATIO,
 504          "tracer-min-branch-ratio",
 505          "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent).",
 506          10, 0, 100)
 507 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
 508          "tracer-min-branch-probability-feedback",
 509          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available.",
 510          80, 0, 100)
 511 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
 512          "tracer-min-branch-probability",
 513          "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available.",
 514          50, 0, 100)
 515
 516 /* The maximum number of incoming edges to consider for crossjumping.  */
 517 DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
 518          "max-crossjump-edges",
 519          "The maximum number of incoming edges to consider for crossjumping.",
 520          100, 0, 0)
 521
 522 /* The minimum number of matching instructions to consider for crossjumping.  */
 523 DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS,
 524      "min-crossjump-insns",
 525      "The minimum number of matching instructions to consider for crossjumping.",
 526      5, 1, 0)
 527
 528 /* The maximum number expansion factor when copying basic blocks.  */
 529 DEFPARAM(PARAM_MAX_GROW_COPY_BB_INSNS,
 530      "max-grow-copy-bb-insns",
 531      "The maximum expansion factor when copying basic blocks.",
 532      8, 0, 0)
 533
 534 /* The maximum number of insns to duplicate when unfactoring computed gotos.  */
 535 DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS,
 536      "max-goto-duplication-insns",
 537      "The maximum number of insns to duplicate when unfactoring computed gotos.",
 538      8, 0, 0)
 539
 540 /* The maximum length of path considered in cse.  */
 541 DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
 542          "max-cse-path-length",
 543          "The maximum length of path considered in cse.",
 544          10, 1, 0)
 545 DEFPARAM(PARAM_MAX_CSE_INSNS,
 546          "max-cse-insns",
 547          "The maximum instructions CSE process before flushing.",
 548          1000, 0, 0)
 549
 550 /* The cost of expression in loop invariant motion that is considered
 551    expensive.  */
 552 DEFPARAM(PARAM_LIM_EXPENSIVE,
 553          "lim-expensive",
 554          "The minimum cost of an expensive expression in the loop invariant motion.",
 555          20, 0, 0)
 556
 557 /* Bound on number of candidates for induction variables below that
 558    all candidates are considered for each use in induction variable
 559    optimizations.  */
 560
 561 DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND,
 562          "iv-consider-all-candidates-bound",
 563          "Bound on number of candidates below that all candidates are considered in iv optimizations.",
 564          40, 0, 0)
 565
 566 /* The induction variable optimizations give up on loops that contain more
 567    induction variable uses.  */
 568
 569 DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES,
 570          "iv-max-considered-uses",
 571          "Bound on number of iv uses in loop optimized in iv optimizations.",
 572          250, 0, 0)
 573
 574 /* If there are at most this number of ivs in the set, try removing unnecessary
 575    ivs from the set always.  */
 576
 577 DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND,
 578          "iv-always-prune-cand-set-bound",
 579          "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization.",
 580          10, 0, 0)
 581
 582 DEFPARAM(PARAM_AVG_LOOP_NITER,
 583          "avg-loop-niter",
 584          "Average number of iterations of a loop.",
 585          10, 1, 0)
 586
 587 DEFPARAM(PARAM_DSE_MAX_OBJECT_SIZE,
 588          "dse-max-object-size",
 589          "Maximum size (in bytes) of objects tracked bytewise by dead store elimination.",
 590          256, 0, 0)
 591
 592 DEFPARAM(PARAM_DSE_MAX_ALIAS_QUERIES_PER_STORE,
 593          "dse-max-alias-queries-per-store",
 594          "Maximum number of queries into the alias oracle per store.",
 595          256, 0, 0)
 596
 597 DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE,
 598          "scev-max-expr-size",
 599          "Bound on size of expressions used in the scalar evolutions analyzer.",
 600          100, 0, 0)
 601
 602 DEFPARAM(PARAM_SCEV_MAX_EXPR_COMPLEXITY,
 603          "scev-max-expr-complexity",
 604          "Bound on the complexity of the expressions in the scalar evolutions analyzer.",
 605          10, 0, 0)
 606
 607 DEFPARAM (PARAM_MAX_TREE_IF_CONVERSION_PHI_ARGS,
 608           "max-tree-if-conversion-phi-args",
 609           "Maximum number of arguments in a PHI supported by TREE if-conversion "
 610           "unless the loop is marked with simd pragma.",
 611           4, 2, 0)
 612
 613 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIGNMENT_CHECKS,
 614          "vect-max-version-for-alignment-checks",
 615          "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alignment check.",
 616          6, 0, 0)
 617
 618 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS,
 619          "vect-max-version-for-alias-checks",
 620          "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alias check.",
 621          10, 0, 0)
 622
 623 DEFPARAM(PARAM_VECT_MAX_PEELING_FOR_ALIGNMENT,
 624          "vect-max-peeling-for-alignment",
 625          "Maximum number of loop peels to enhance alignment of data references in a loop.",
 626          -1, -1, 64)
 627
 628 DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS,
 629          "max-cselib-memory-locations",
 630          "The maximum memory locations recorded by cselib.",
 631          500, 0, 0)
 632
 633 #ifdef ENABLE_GC_ALWAYS_COLLECT
 634 # define GGC_MIN_EXPAND_DEFAULT 0
 635 # define GGC_MIN_HEAPSIZE_DEFAULT 0
 636 #else
 637 # define GGC_MIN_EXPAND_DEFAULT 30
 638 # define GGC_MIN_HEAPSIZE_DEFAULT 4096
 639 #endif
 640
 641 DEFPARAM(GGC_MIN_EXPAND,
 642          "ggc-min-expand",
 643          "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap.",
 644          GGC_MIN_EXPAND_DEFAULT, 0, 0)
 645
 646 DEFPARAM(GGC_MIN_HEAPSIZE,
 647          "ggc-min-heapsize",
 648          "Minimum heap size before we start collecting garbage, in kilobytes.",
 649          GGC_MIN_HEAPSIZE_DEFAULT, 0, 0)
 650
 651 #undef GGC_MIN_EXPAND_DEFAULT
 652 #undef GGC_MIN_HEAPSIZE_DEFAULT
 653
 654 DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
 655          "max-reload-search-insns",
 656          "The maximum number of instructions to search backward when looking for equivalent reload.",
 657          100, 0, 0)
 658
 659 DEFPARAM(PARAM_SINK_FREQUENCY_THRESHOLD,
 660          "sink-frequency-threshold",
 661          "Target block's relative execution frequency (as a percentage) required to sink a statement.",
 662          75, 0, 100)
 663
 664 DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS,
 665          "max-sched-region-blocks",
 666          "The maximum number of blocks in a region to be considered for interblock scheduling.",
 667          10, 0, 0)
 668
 669 DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS,
 670          "max-sched-region-insns",
 671          "The maximum number of insns in a region to be considered for interblock scheduling.",
 672          100, 0, 0)
 673
 674 DEFPARAM(PARAM_MAX_PIPELINE_REGION_BLOCKS,
 675          "max-pipeline-region-blocks",
 676          "The maximum number of blocks in a region to be considered for interblock scheduling.",
 677          15, 0, 0)
 678
 679 DEFPARAM(PARAM_MAX_PIPELINE_REGION_INSNS,
 680          "max-pipeline-region-insns",
 681          "The maximum number of insns in a region to be considered for interblock scheduling.",
 682          200, 0, 0)
 683
 684 DEFPARAM(PARAM_MIN_SPEC_PROB,
 685          "min-spec-prob",
 686          "The minimum probability of reaching a source block for interblock speculative scheduling.",
 687          40, 0, 0)
 688
 689 DEFPARAM(PARAM_MAX_SCHED_EXTEND_REGIONS_ITERS,
 690          "max-sched-extend-regions-iters",
 691          "The maximum number of iterations through CFG to extend regions.",
 692          0, 0, 0)
 693
 694 DEFPARAM(PARAM_MAX_SCHED_INSN_CONFLICT_DELAY,
 695          "max-sched-insn-conflict-delay",
 696          "The maximum conflict delay for an insn to be considered for speculative motion.",
 697          3, 1, 10)
 698
 699 DEFPARAM(PARAM_SCHED_SPEC_PROB_CUTOFF,
 700          "sched-spec-prob-cutoff",
 701          "The minimal probability of speculation success (in percents), so that speculative insn will be scheduled.",
 702          40, 0, 100)
 703
 704 DEFPARAM(PARAM_SCHED_STATE_EDGE_PROB_CUTOFF,
 705          "sched-state-edge-prob-cutoff",
 706          "The minimum probability an edge must have for the scheduler to save its state across it.",
 707          10, 0, 100)
 708
 709 DEFPARAM(PARAM_SELSCHED_MAX_LOOKAHEAD,
 710          "selsched-max-lookahead",
 711          "The maximum size of the lookahead window of selective scheduling.",
 712          50, 0, 0)
 713
 714 DEFPARAM(PARAM_SELSCHED_MAX_SCHED_TIMES,
 715          "selsched-max-sched-times",
 716          "Maximum number of times that an insn could be scheduled.",
 717          2, 1, 0)
 718
 719 DEFPARAM(PARAM_SELSCHED_INSNS_TO_RENAME,
 720          "selsched-insns-to-rename",
 721          "Maximum number of instructions in the ready list that are considered eligible for renaming.",
 722          2, 0, 0)
 723
 724 DEFPARAM (PARAM_SCHED_MEM_TRUE_DEP_COST,
 725           "sched-mem-true-dep-cost",
 726           "Minimal distance between possibly conflicting store and load.",
 727           1, 0, 0)
 728
 729 DEFPARAM (PARAM_SCHED_AUTOPREF_QUEUE_DEPTH,
 730           "sched-autopref-queue-depth",
 731           "Hardware autoprefetcher scheduler model control flag.  Number of lookahead cycles the model looks into; at '0' only enable instruction sorting heuristic.  Disabled by default.",
 732           -1, 0, 0)
 733
 734 DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
 735          "max-last-value-rtl",
 736          "The maximum number of RTL nodes that can be recorded as combiner's last value.",
 737          10000, 0, 0)
 738
 739 DEFPARAM(PARAM_MAX_COMBINE_INSNS,
 740          "max-combine-insns",
 741          "The maximum number of insns combine tries to combine.",
 742          4, 2, 4)
 743
 744 /* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
 745    {signed,unsigned} integral types.  This determines N.
 746    Experimentation shows 251 to be a good value that generates the
 747    least amount of garbage for allocating the TREE_VEC storage.  */
 748 DEFPARAM (PARAM_INTEGER_SHARE_LIMIT,
 749           "integer-share-limit",
 750           "The upper bound for sharing integer constants.",
 751           251, 2, 2)
 752
 753 DEFPARAM (PARAM_SSP_BUFFER_SIZE,
 754           "ssp-buffer-size",
 755           "The lower bound for a buffer to be considered for stack smashing protection.",
 756           8, 1, 0)
 757
 758 DEFPARAM (PARAM_MIN_SIZE_FOR_STACK_SHARING,
 759           "min-size-for-stack-sharing",
 760           "The minimum size of variables taking part in stack slot sharing "
 761           "when not optimizing.",
 762           32, 0, 0)
 763
 764 /* When we thread through a block we have to make copies of the
 765    statements within the block.  Clearly for large blocks the code
 766    duplication is bad.
 767
 768    PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number
 769    of statements and PHI nodes allowed in a block which is going to
 770    be duplicated for thread jumping purposes.
 771
 772    Some simple analysis showed that more than 99% of the jump
 773    threading opportunities are for blocks with less than 15
 774    statements.  So we can get the benefits of jump threading
 775    without excessive code bloat for pathological cases with the
 776    throttle set at 15 statements.  */
 777 DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS,
 778           "max-jump-thread-duplication-stmts",
 779           "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps.",
 780           15, 0, 0)
 781
 782 /* This is the maximum number of fields a variable may have before the pointer analysis machinery
 783    will stop trying to treat it in a field-sensitive manner.
 784    There are programs out there with thousands of fields per structure, and handling them
 785    field-sensitively is not worth the cost.  */
 786 DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE,
 787           "max-fields-for-field-sensitive",
 788           "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable.",
 789           0, 0, 0)
 790
 791 DEFPARAM(PARAM_MAX_SCHED_READY_INSNS,
 792          "max-sched-ready-insns",
 793          "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass.",
 794          100, 1, 0)
 795
 796 /* This is the maximum number of active local stores RTL DSE will consider.  */
 797 DEFPARAM (PARAM_MAX_DSE_ACTIVE_LOCAL_STORES,
 798           "max-dse-active-local-stores",
 799           "Maximum number of active local stores in RTL dead store elimination.",
 800           5000, 0, 0)
 801
 802 /* Prefetching and cache-optimizations related parameters.  Default values are
 803    usually set by machine description.  */
 804
 805 /* The number of insns executed before prefetch is completed.  */
 806
 807 DEFPARAM (PARAM_PREFETCH_LATENCY,
 808          "prefetch-latency",
 809          "The number of insns executed before prefetch is completed.",
 810          200, 0, 0)
 811
 812 /* The number of prefetches that can run at the same time.  */
 813
 814 DEFPARAM (PARAM_SIMULTANEOUS_PREFETCHES,
 815           "simultaneous-prefetches",
 816           "The number of prefetches that can run at the same time.",
 817           3, 0, 0)
 818
 819 /* The size of L1 cache in kB.  */
 820
 821 DEFPARAM (PARAM_L1_CACHE_SIZE,
 822           "l1-cache-size",
 823           "The size of L1 cache.",
 824           64, 0, 0)
 825
 826 /* The size of L1 cache line in bytes.  */
 827
 828 DEFPARAM (PARAM_L1_CACHE_LINE_SIZE,
 829           "l1-cache-line-size",
 830           "The size of L1 cache line.",
 831           32, 0, 0)
 832
 833 /* The size of L2 cache in kB.  */
 834
 835 DEFPARAM (PARAM_L2_CACHE_SIZE,
 836           "l2-cache-size",
 837           "The size of L2 cache.",
 838           512, 0, 0)
 839
 840 /* Whether software prefetch hints should be issued for non-constant
 841    strides.  */
 842
 843 DEFPARAM (PARAM_PREFETCH_DYNAMIC_STRIDES,
 844           "prefetch-dynamic-strides",
 845           "Whether software prefetch hints should be issued for non-constant "
 846           "strides.",
 847           1, 0, 1)
 848
 849 /* The minimum constant stride beyond which we should use prefetch hints
 850    for.  */
 851
 852 DEFPARAM (PARAM_PREFETCH_MINIMUM_STRIDE,
 853           "prefetch-minimum-stride",
 854           "The minimum constant stride beyond which we should use prefetch "
 855           "hints for.",
 856           -1, 0, 0)
 857
 858 /* Maximum number of statements in loop nest for loop interchange.  */
 859
 860 DEFPARAM (PARAM_LOOP_INTERCHANGE_MAX_NUM_STMTS,
 861           "loop-interchange-max-num-stmts",
 862           "The maximum number of stmts in loop nest for loop interchange.",
 863           64, 0, 0)
 864
 865 /* Minimum stride ratio for loop interchange to be profitiable.  */
 866
 867 DEFPARAM (PARAM_LOOP_INTERCHANGE_STRIDE_RATIO,
 868           "loop-interchange-stride-ratio",
 869           "The minimum stride ratio for loop interchange to be profitable.",
 870           2, 0, 0)
 871
 872 /* Whether we should use canonical types rather than deep "structural"
 873    type checking.  Setting this value to 1 (the default) improves
 874    compilation performance in the C++ and Objective-C++ front end;
 875    this value should only be set to zero to work around bugs in the
 876    canonical type system by disabling it.  */
 877
 878 DEFPARAM (PARAM_USE_CANONICAL_TYPES,
 879           "use-canonical-types",
 880           "Whether to use canonical types.",
 881           1, 0, 1)
 882
 883 DEFPARAM (PARAM_MAX_PARTIAL_ANTIC_LENGTH,
 884           "max-partial-antic-length",
 885           "Maximum length of partial antic set when performing tree pre optimization.",
 886           100, 0, 0)
 887
 888 /* The following is used as a stop-gap limit for cases where really deep
 889    loop nests cause compile-time to blow up.  If we hit this limit,
 890    FRE and PRE will value-number outer loops (but the outermost) in a
 891    loop nest non-optimistically.  */
 892
 893 DEFPARAM (PARAM_RPO_VN_MAX_LOOP_DEPTH,
 894           "rpo-vn-max-loop-depth",
 895           "Maximum depth of a loop nest to fully value-number optimistically.",
 896           7, 2, 0)
 897
 898 /* The following is used as a stop-gap limit for cases where really huge
 899    functions blow up compile-time use too much.  It limits the number of
 900    alias-queries we do for finding common subexpressions for memory loads and
 901    stores.  The number of alias-queries is otherwise limited by the number of
 902    stores on paths to function entry.  */
 903
 904 DEFPARAM (PARAM_SCCVN_MAX_ALIAS_QUERIES_PER_ACCESS,
 905           "sccvn-max-alias-queries-per-access",
 906           "Maximum number of disambiguations to perform per memory access.",
 907           1000, 0, 0)
 908
 909 DEFPARAM (PARAM_IRA_MAX_LOOPS_NUM,
 910           "ira-max-loops-num",
 911           "Max loops number for regional RA.",
 912           100, 0, 0)
 913
 914 DEFPARAM (PARAM_IRA_MAX_CONFLICT_TABLE_SIZE,
 915           "ira-max-conflict-table-size",
 916           "Max size of conflict table in MB.",
 917           1000, 0, 0)
 918
 919 DEFPARAM (PARAM_IRA_LOOP_RESERVED_REGS,
 920           "ira-loop-reserved-regs",
 921           "The number of registers in each class kept unused by loop invariant motion.",
 922           2, 0, 0)
 923
 924 DEFPARAM (PARAM_LRA_MAX_CONSIDERED_RELOAD_PSEUDOS,
 925           "lra-max-considered-reload-pseudos",
 926           "The max number of reload pseudos which are considered during spilling a non-reload pseudo.",
 927           500, 0, 0)
 928
 929 DEFPARAM (PARAM_LRA_INHERITANCE_EBB_PROBABILITY_CUTOFF,
 930           "lra-inheritance-ebb-probability-cutoff",
 931           "Minimal fall-through edge probability in percentage used to add BB to inheritance EBB in LRA.",
 932           40, 0, 100)
 933
 934 /* Switch initialization conversion will refuse to create arrays that are
 935    bigger than this parameter times the number of switch branches.  */
 936
 937 DEFPARAM (PARAM_SWITCH_CONVERSION_BRANCH_RATIO,
 938           "switch-conversion-max-branch-ratio",
 939           "The maximum ratio between array size and switch branches for "
 940           "a switch conversion to take place.",
 941           8, 1, 0)
 942
 943 /* Size of tiles when doing loop blocking.  */
 944
 945 DEFPARAM (PARAM_LOOP_BLOCK_TILE_SIZE,
 946           "loop-block-tile-size",
 947           "Size of tiles for loop blocking.",
 948           51, 0, 0)
 949
 950 /* Maximal number of parameters that we allow in a SCoP.  */
 951
 952 DEFPARAM (PARAM_GRAPHITE_MAX_NB_SCOP_PARAMS,
 953           "graphite-max-nb-scop-params",
 954           "Maximum number of parameters in a SCoP.",
 955           10, 0, 0)
 956
 957 /* Maximal number of array references in a scop.  */
 958
 959 DEFPARAM (PARAM_GRAPHITE_MAX_ARRAYS_PER_SCOP,
 960           "graphite-max-arrays-per-scop",
 961           "Maximum number of arrays per scop.",
 962           100, 0, 0)
 963
 964 DEFPARAM (PARAM_MAX_ISL_OPERATIONS,
 965           "max-isl-operations",
 966           "Maximum number of isl operations, 0 means unlimited.",
 967           350000, 0, 0)
 968
 969 /* For testsuite purposes allow to check for codegen error handling.  */
 970 DEFPARAM (PARAM_GRAPHITE_ALLOW_CODEGEN_ERRORS,
 971           "graphite-allow-codegen-errors",
 972           "Whether codegen errors should be ICEs when -fchecking.",
 973           0, 0, 1)
 974
 975 /* Avoid data dependence analysis on very large loops.  */
 976 DEFPARAM (PARAM_LOOP_MAX_DATAREFS_FOR_DATADEPS,
 977           "loop-max-datarefs-for-datadeps",
 978           "Maximum number of datarefs in loop for building loop data dependencies.",
 979           1000, 0, 0)
 980
 981 /* Avoid doing loop invariant motion on very large loops.  */
 982
 983 DEFPARAM (PARAM_LOOP_INVARIANT_MAX_BBS_IN_LOOP,
 984           "loop-invariant-max-bbs-in-loop",
 985           "Max basic blocks number in loop for loop invariant motion.",
 986           10000, 0, 0)
 987
 988 /* When the parameter is 1, use the internal function id
 989    to look up for profile data. Otherwise, use a more stable
 990    external id based on assembler name and source location. */
 991 DEFPARAM (PARAM_PROFILE_FUNC_INTERNAL_ID,
 992           "profile-func-internal-id",
 993           "Use internal function id in profile lookup.",
 994           0, 0, 1)
 995
 996 /* When the parameter is 1, track the most frequent N target
 997    addresses in indirect-call profile. This disables
 998    indirect_call_profiler_v2 which tracks single target.  */
 999 DEFPARAM (PARAM_INDIR_CALL_TOPN_PROFILE,
1000           "indir-call-topn-profile",
1001           "Track top N target addresses in indirect-call profile.",
1002           0, 0, 1)
1003
1004 /* Avoid SLP vectorization of large basic blocks.  */
1005 DEFPARAM (PARAM_SLP_MAX_INSNS_IN_BB,
1006           "slp-max-insns-in-bb",
1007           "Maximum number of instructions in basic block to be considered for "
1008           "SLP vectorization.", 1000, 0, 0)
1009
1010 DEFPARAM (PARAM_MIN_INSN_TO_PREFETCH_RATIO,
1011           "min-insn-to-prefetch-ratio",
1012           "Min. ratio of insns to prefetches to enable prefetching for "
1013           "a loop with an unknown trip count.",
1014           9, 0, 0)
1015
1016 DEFPARAM (PARAM_PREFETCH_MIN_INSN_TO_MEM_RATIO,
1017           "prefetch-min-insn-to-mem-ratio",
1018           "Min. ratio of insns to mem ops to enable prefetching in a loop.",
1019           3, 0, 0)
1020
1021 /* Set maximum hash table size for var tracking.  */
1022
1023 DEFPARAM (PARAM_MAX_VARTRACK_SIZE,
1024           "max-vartrack-size",
1025           "Max. size of var tracking hash tables.",
1026           50000000, 0, 0)
1027
1028 /* Set maximum recursion depth for var tracking expression expansion
1029    and resolution.  */
1030
1031 DEFPARAM (PARAM_MAX_VARTRACK_EXPR_DEPTH,
1032           "max-vartrack-expr-depth",
1033           "Max. recursion depth for expanding var tracking expressions.",
1034           12, 0, 0)
1035
1036 /* Set maximum length of value location list for which var tracking
1037    should add reverse operations.  */
1038
1039 DEFPARAM (PARAM_MAX_VARTRACK_REVERSE_OP_SIZE,
1040           "max-vartrack-reverse-op-size",
1041           "Max. size of loc list for which reverse ops should be added.",
1042           50, 0, 0)
1043
1044 /* Set a threshold to discard debug markers (e.g. debug begin stmt
1045    markers) when expanding a function to RTL, or inlining it into
1046    another function.  */
1047
1048 DEFPARAM (PARAM_MAX_DEBUG_MARKER_COUNT,
1049           "max-debug-marker-count",
1050           "Max. count of debug markers to expand or inline.",
1051           100000, 0, 0)
1052
1053 /* Set minimum insn uid for non-debug insns.  */
1054
1055 DEFPARAM (PARAM_MIN_NONDEBUG_INSN_UID,
1056           "min-nondebug-insn-uid",
1057           "The minimum UID to be used for a nondebug insn.",
1058           0, 0, 0)
1059
1060 DEFPARAM (PARAM_IPA_SRA_PTR_GROWTH_FACTOR,
1061           "ipa-sra-ptr-growth-factor",
1062           "Maximum allowed growth of number and total size of new parameters "
1063           "that ipa-sra replaces a pointer to an aggregate with.",
1064           2, 0, 0)
1065
1066 DEFPARAM (PARAM_TM_MAX_AGGREGATE_SIZE,
1067           "tm-max-aggregate-size",
1068           "Size in bytes after which thread-local aggregates should be "
1069           "instrumented with the logging functions instead of save/restore "
1070           "pairs.",
1071           9, 0, 0)
1072
1073 DEFPARAM (PARAM_SRA_MAX_SCALARIZATION_SIZE_SPEED,
1074           "sra-max-scalarization-size-Ospeed",
1075           "Maximum size, in storage units, of an aggregate which should be "
1076           "considered for scalarization when compiling for speed.",
1077           0, 0, 0)
1078
1079 DEFPARAM (PARAM_SRA_MAX_SCALARIZATION_SIZE_SIZE,
1080           "sra-max-scalarization-size-Osize",
1081           "Maximum size, in storage units, of an aggregate which should be "
1082           "considered for scalarization when compiling for size.",
1083           0, 0, 0)
1084
1085 DEFPARAM (PARAM_IPA_CP_VALUE_LIST_SIZE,
1086           "ipa-cp-value-list-size",
1087           "Maximum size of a list of values associated with each parameter for "
1088           "interprocedural constant propagation.",
1089           8, 0, 0)
1090
1091 DEFPARAM (PARAM_IPA_CP_EVAL_THRESHOLD,
1092           "ipa-cp-eval-threshold",
1093           "Threshold ipa-cp opportunity evaluation that is still considered "
1094           "beneficial to clone.",
1095           500, 0, 0)
1096
1097 DEFPARAM (PARAM_IPA_CP_RECURSION_PENALTY,
1098           "ipa-cp-recursion-penalty",
1099           "Percentage penalty the recursive functions will receive when they "
1100           "are evaluated for cloning.",
1101           40, 0, 100)
1102
1103 DEFPARAM (PARAM_IPA_CP_SINGLE_CALL_PENALTY,
1104           "ipa-cp-single-call-penalty",
1105           "Percentage penalty functions containing a single call to another "
1106           "function will receive when they are evaluated for cloning.",
1107           15, 0, 100)
1108
1109 DEFPARAM (PARAM_IPA_MAX_AGG_ITEMS,
1110           "ipa-max-agg-items",
1111           "Maximum number of aggregate content items for a parameter in "
1112           "jump functions and lattices.",
1113           16, 0, 0)
1114
1115 DEFPARAM (PARAM_IPA_CP_LOOP_HINT_BONUS,
1116           "ipa-cp-loop-hint-bonus",
1117           "Compile-time bonus IPA-CP assigns to candidates which make loop "
1118           "bounds or strides known.",
1119           64, 0, 0)
1120
1121 DEFPARAM (PARAM_IPA_CP_ARRAY_INDEX_HINT_BONUS,
1122           "ipa-cp-array-index-hint-bonus",
1123           "Compile-time bonus IPA-CP assigns to candidates which make an array "
1124           "index known.",
1125           48, 0, 0)
1126
1127 DEFPARAM (PARAM_IPA_MAX_AA_STEPS,
1128           "ipa-max-aa-steps",
1129           "Maximum number of statements that will be visited by IPA formal "
1130           "parameter analysis based on alias analysis in any given function.",
1131           25000, 0, 0)
1132
1133 /* WHOPR partitioning configuration.  */
1134
1135 DEFPARAM (PARAM_LTO_PARTITIONS,
1136           "lto-partitions",
1137           "Number of partitions the program should be split to.",
1138           128, 1, 0)
1139
1140 DEFPARAM (MIN_PARTITION_SIZE,
1141           "lto-min-partition",
1142           "Minimal size of a partition for LTO (in estimated instructions).",
1143           10000, 0, 0)
1144
1145 DEFPARAM (MAX_PARTITION_SIZE,
1146           "lto-max-partition",
1147           "Maximal size of a partition for LTO (in estimated instructions).",
1148           1000000, 0, INT_MAX)
1149
1150 /* Diagnostic parameters.  */
1151
1152 DEFPARAM (CXX_MAX_NAMESPACES_FOR_DIAGNOSTIC_HELP,
1153           "cxx-max-namespaces-for-diagnostic-help",
1154           "Maximum number of namespaces to search for alternatives when "
1155           "name lookup fails.",
1156           1000, 0, 0)
1157
1158 /* Maximum number of conditional store pairs that can be sunk.  */
1159 DEFPARAM (PARAM_MAX_STORES_TO_SINK,
1160           "max-stores-to-sink",
1161           "Maximum number of conditional store pairs that can be sunk.",
1162           2, 0, 0)
1163
1164 /* Override CASE_VALUES_THRESHOLD of when to switch from doing switch
1165    statements via if statements to using a table jump operation.  If the value
1166    is 0, the default CASE_VALUES_THRESHOLD will be used.  */
1167 DEFPARAM (PARAM_CASE_VALUES_THRESHOLD,
1168           "case-values-threshold",
1169           "The smallest number of different values for which it is best to "
1170           "use a jump-table instead of a tree of conditional branches, "
1171           "if 0, use the default for the machine.",
1172           0, 0, 0)
1173
1174 /* Data race flags for C++0x memory model compliance.  */
1175 DEFPARAM (PARAM_ALLOW_STORE_DATA_RACES,
1176           "allow-store-data-races",
1177           "Allow new data races on stores to be introduced.",
1178           0, 0, 1)
1179
1180 /* Reassociation width to be used by tree reassoc optimization.  */
1181 DEFPARAM (PARAM_TREE_REASSOC_WIDTH,
1182           "tree-reassoc-width",
1183           "Set the maximum number of instructions executed in parallel in "
1184           "reassociated tree.  If 0, use the target dependent heuristic.",
1185           0, 0, 0)
1186
1187 DEFPARAM (PARAM_MAX_TAIL_MERGE_COMPARISONS,
1188           "max-tail-merge-comparisons",
1189           "Maximum amount of similar bbs to compare a bb with.",
1190           10, 0, 0)
1191
1192 DEFPARAM (PARAM_STORE_MERGING_ALLOW_UNALIGNED,
1193           "store-merging-allow-unaligned",
1194           "Allow the store merging pass to introduce unaligned stores "
1195           "if it is legal to do so.",
1196           1, 0, 1)
1197
1198 DEFPARAM (PARAM_MAX_STORES_TO_MERGE,
1199           "max-stores-to-merge",
1200           "Maximum number of constant stores to merge in the "
1201           "store merging pass.",
1202           64, 2, 0)
1203
1204 DEFPARAM (PARAM_MAX_TAIL_MERGE_ITERATIONS,
1205           "max-tail-merge-iterations",
1206           "Maximum amount of iterations of the pass over a function.",
1207           2, 0, 0)
1208
1209 /* Maximum number of strings for which strlen optimization pass will
1210    track string lenths.  */
1211 DEFPARAM (PARAM_MAX_TRACKED_STRLENS,
1212           "max-tracked-strlens",
1213           "Maximum number of strings for which strlen optimization pass will "
1214           "track string lengths.",
1215           10000, 0, 0)
1216
1217 /* Keep this in sync with the sched_pressure_algorithm enum.  */
1218 DEFPARAM (PARAM_SCHED_PRESSURE_ALGORITHM,
1219           "sched-pressure-algorithm",
1220           "Which -fsched-pressure algorithm to apply.",
1221           1, 1, 2)
1222
1223 /* Maximum length of candidate scans in straight-line strength reduction.  */
1224 DEFPARAM (PARAM_MAX_SLSR_CANDIDATE_SCAN,
1225           "max-slsr-cand-scan",
1226           "Maximum length of candidate scans for straight-line "
1227           "strength reduction.",
1228           50, 1, 999999)
1229
1230 /* ASan stands for AddressSanitizer: https://github.com/google/sanitizers.  */
1231
1232 DEFPARAM (PARAM_ASAN_STACK,
1233          "asan-stack",
1234          "Enable asan stack protection.",
1235          1, 0, 1)
1236
1237 DEFPARAM (PARAM_ASAN_PROTECT_ALLOCAS,
1238         "asan-instrument-allocas",
1239         "Enable asan allocas/VLAs protection.",
1240         1, 0, 1)
1241
1242 DEFPARAM (PARAM_ASAN_GLOBALS,
1243          "asan-globals",
1244          "Enable asan globals protection.",
1245          1, 0, 1)
1246
1247 DEFPARAM (PARAM_ASAN_INSTRUMENT_WRITES,
1248          "asan-instrument-writes",
1249          "Enable asan store operations protection.",
1250          1, 0, 1)
1251
1252 DEFPARAM (PARAM_ASAN_INSTRUMENT_READS,
1253          "asan-instrument-reads",
1254          "Enable asan load operations protection.",
1255          1, 0, 1)
1256
1257 DEFPARAM (PARAM_ASAN_MEMINTRIN,
1258          "asan-memintrin",
1259          "Enable asan builtin functions protection.",
1260          1, 0, 1)
1261
1262 DEFPARAM (PARAM_ASAN_USE_AFTER_RETURN,
1263          "asan-use-after-return",
1264          "Enable asan detection of use-after-return bugs.",
1265          1, 0, 1)
1266
1267 DEFPARAM (PARAM_ASAN_INSTRUMENTATION_WITH_CALL_THRESHOLD,
1268          "asan-instrumentation-with-call-threshold",
1269          "Use callbacks instead of inline code if number of accesses "
1270          "in function becomes greater or equal to this number.",
1271          7000, 0, INT_MAX)
1272
1273 DEFPARAM (PARAM_USE_AFTER_SCOPE_DIRECT_EMISSION_THRESHOLD,
1274          "use-after-scope-direct-emission-threshold",
1275          "Use direct poisoning/unpoisoning instructions for variables "
1276          "smaller or equal to this number.",
1277          256, 0, INT_MAX)
1278
1279 DEFPARAM (PARAM_UNINIT_CONTROL_DEP_ATTEMPTS,
1280           "uninit-control-dep-attempts",
1281           "Maximum number of nested calls to search for control dependencies "
1282           "during uninitialized variable analysis.",
1283           1000, 1, 0)
1284
1285 DEFPARAM (PARAM_FSM_SCALE_PATH_STMTS,
1286           "fsm-scale-path-stmts",
1287           "Scale factor to apply to the number of statements in a threading path when comparing to the number of (scaled) blocks.",
1288           2, 1, 10)
1289
1290 DEFPARAM (PARAM_FSM_MAXIMUM_PHI_ARGUMENTS,
1291           "fsm-maximum-phi-arguments",
1292           "Maximum number of arguments a PHI may have before the FSM threader will not try to thread through its block.",
1293           100, 1, 999999)
1294
1295 DEFPARAM (PARAM_FSM_SCALE_PATH_BLOCKS,
1296           "fsm-scale-path-blocks",
1297           "Scale factor to apply to the number of blocks in a threading path when comparing to the number of (scaled) statements.",
1298           3, 1, 10)
1299
1300 DEFPARAM (PARAM_MAX_FSM_THREAD_PATH_INSNS,
1301           "max-fsm-thread-path-insns",
1302           "Maximum number of instructions to copy when duplicating blocks on a finite state automaton jump thread path.",
1303           100, 1, 999999)
1304
1305 DEFPARAM (PARAM_MAX_FSM_THREAD_LENGTH,
1306           "max-fsm-thread-length",
1307           "Maximum number of basic blocks on a finite state automaton jump thread path.",
1308           10, 1, 999999)
1309
1310 DEFPARAM (PARAM_MAX_FSM_THREAD_PATHS,
1311           "max-fsm-thread-paths",
1312           "Maximum number of new jump thread paths to create for a finite state automaton.",
1313           50, 1, 999999)
1314
1315 DEFPARAM (PARAM_PARLOOPS_CHUNK_SIZE,
1316           "parloops-chunk-size",
1317           "Chunk size of omp schedule for loops parallelized by parloops.",
1318           0, 0, 0)
1319
1320 DEFPARAMENUM5 (PARAM_PARLOOPS_SCHEDULE,
1321                "parloops-schedule",
1322                "Schedule type of omp schedule for loops parallelized by "
1323                "parloops (static, dynamic, guided, auto, runtime).",
1324                static,
1325                static, dynamic, guided, auto, runtime)
1326
1327 DEFPARAM (PARAM_PARLOOPS_MIN_PER_THREAD,
1328           "parloops-min-per-thread",
1329           "Minimum number of iterations per thread of an innermost "
1330           "parallelized loop.",
1331           100, 2, 0)
1332
1333 DEFPARAM (PARAM_MAX_SSA_NAME_QUERY_DEPTH,
1334           "max-ssa-name-query-depth",
1335           "Maximum recursion depth allowed when querying a property of an"
1336           " SSA name.",
1337           3, 1, 10)
1338
1339 DEFPARAM (PARAM_MAX_RTL_IF_CONVERSION_INSNS,
1340           "max-rtl-if-conversion-insns",
1341           "Maximum number of insns in a basic block to consider for RTL "
1342           "if-conversion.",
1343           10, 0, 99)
1344
1345 DEFPARAM (PARAM_MAX_RTL_IF_CONVERSION_PREDICTABLE_COST,
1346           "max-rtl-if-conversion-predictable-cost",
1347           "Maximum permissible cost for the sequence that would be "
1348           "generated by the RTL if-conversion pass for a branch that "
1349           "is considered predictable.",
1350           20, 0, 200)
1351
1352 DEFPARAM (PARAM_MAX_RTL_IF_CONVERSION_UNPREDICTABLE_COST,
1353           "max-rtl-if-conversion-unpredictable-cost",
1354           "Maximum permissible cost for the sequence that would be "
1355           "generated by the RTL if-conversion pass for a branch that "
1356           "is considered unpredictable.",
1357           40, 0, 200)
1358
1359 DEFPARAM (PARAM_HSA_GEN_DEBUG_STORES,
1360           "hsa-gen-debug-stores",
1361           "Level of hsa debug stores verbosity.",
1362           0, 0, 1)
1363
1364 DEFPARAM (PARAM_MAX_SPECULATIVE_DEVIRT_MAYDEFS,
1365           "max-speculative-devirt-maydefs",
1366           "Maximum number of may-defs visited when devirtualizing "
1367           "speculatively.", 50, 0, 0)
1368
1369 DEFPARAM (PARAM_MAX_VRP_SWITCH_ASSERTIONS,
1370           "max-vrp-switch-assertions",
1371           "Maximum number of assertions to add along the default "
1372           "edge of a switch statement during VRP.",
1373           10, 0, 0)
1374
1375 DEFPARAM (PARAM_VECT_EPILOGUES_NOMASK,
1376           "vect-epilogues-nomask",
1377           "Enable loop epilogue vectorization using smaller vector size.",
1378           0, 0, 1)
1379
1380 DEFPARAM(PARAM_UNROLL_JAM_MIN_PERCENT,
1381          "unroll-jam-min-percent",
1382          "Minimum percentage of memrefs that must go away for unroll-and-jam to be considered profitable.",
1383          1, 0, 100)
1384
1385 DEFPARAM(PARAM_UNROLL_JAM_MAX_UNROLL,
1386          "unroll-jam-max-unroll",
1387          "Maximum unroll factor for the unroll-and-jam transformation.",
1388          4, 0, 0)
1389
1390 DEFPARAM(PARAM_AVOID_FMA_MAX_BITS,
1391          "avoid-fma-max-bits",
1392          "Maximum number of bits for which we avoid creating FMAs.",
1393          0, 0, 512)
1394
1395 DEFPARAM(PARAM_LOGICAL_OP_NON_SHORT_CIRCUIT,
1396          "logical-op-non-short-circuit",
1397          "True if a non-short-circuit operation is optimal.",
1398          -1, -1, 1)
1399
1400 DEFPARAM(PARAM_LOOP_VERSIONING_MAX_INNER_INSNS,
1401          "loop-versioning-max-inner-insns",
1402          "The maximum number of instructions in an inner loop that is being"
1403          " considered for versioning.",
1404          200, 0, 0)
1405
1406 DEFPARAM(PARAM_LOOP_VERSIONING_MAX_OUTER_INSNS,
1407          "loop-versioning-max-outer-insns",
1408          "The maximum number of instructions in an outer loop that is being"
1409          " considered for versioning, on top of the instructions in inner"
1410          " loops.",
1411          100, 0, 0)
1412
1413 /*
1414
1415 Local variables:
1416 mode:c
1417 End:
1418 */