1/* params.def - Run-time parameters. 2 Copyright (C) 2001, 2002, 2004, 2005 Free Software Foundation, Inc. 3 Written by Mark Mitchell <mark@codesourcery.com>. 4 5This file is part of GCC. 6 7GCC is free software; you can redistribute it and/or modify it under 8the terms of the GNU General Public License as published by the Free 9Software Foundation; either version 2, or (at your option) any later 10version. 11 12GCC is distributed in the hope that it will be useful, but WITHOUT ANY 13WARRANTY; without even the implied warranty of MERCHANTABILITY or 14FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 15for more details. 16 17You should have received a copy of the GNU General Public License 18along with GCC; see the file COPYING. If not, write to the Free 19Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 2002110-1301, USA. 21 22*/ 23 24/* This file contains definitions for language-independent 25 parameters. The DEFPARAM macro takes 6 arguments: 26 27 - The enumeral corresponding to this parameter. 28 29 - The name that can be used to set this parameter using the 30 command-line option `--param <name>=<value>'. 31 32 - A help string explaining how the parameter is used. 33 34 - A default value for the parameter. 35 36 - The minimum acceptable value for the parameter. 37 38 - The maximum acceptable value for the parameter (if greater than 39 the minimum). 40 41 Be sure to add an entry to invoke.texi summarizing the parameter. */ 42 43/* The maximum number of fields in a variable with only implicit uses 44 for which structure aliasing will consider trying to track each 45 field. The default is 5. */ 46DEFPARAM (PARAM_SALIAS_MAX_IMPLICIT_FIELDS, 47 "salias-max-implicit-fields", 48 "The maximum number of fields in a structure variable without direct structure accesses that GCC will attempt to track separately", 49 5, 0, 0) 50 51/* The maximum number of array elements structure aliasing will decompose 52 an array for. The default is 4. */ 53DEFPARAM (PARAM_SALIAS_MAX_ARRAY_ELEMENTS, 54 "salias-max-array-elements", 55 "The maximum number of elements in an array for wich we track its elements separately", 56 4, 0, 0) 57 58/* The maximum structure size at which the scalar replacement of 59 aggregates (SRA) pass will perform block copies. The default 60 value, 0, implies that GCC will select the most appropriate size 61 itself. */ 62DEFPARAM (PARAM_SRA_MAX_STRUCTURE_SIZE, 63 "sra-max-structure-size", 64 "The maximum structure size (in bytes) for which GCC will " 65 "use by-element copies", 66 0, 0, 0) 67 68/* The maximum number of structure fields which the SRA pass will 69 instantiate to avoid block copies. The default value, 0, implies 70 that GCC will select the appropriate value itself. */ 71DEFPARAM (PARAM_SRA_MAX_STRUCTURE_COUNT, 72 "sra-max-structure-count", 73 "The maximum number of structure fields for which GCC will " 74 "use by-element copies", 75 0, 0, 0) 76 77/* The ratio between instantiated fields and the complete structure 78 size. We say that if the ratio of the number of bytes in 79 instantiated fields to the number of bytes in the complete 80 structure exceeds this parameter, or if the number of instantiated 81 fields to the total number of fields exceeds this parameter, then 82 block copies are not used. The default is 75%. */ 83DEFPARAM (PARAM_SRA_FIELD_STRUCTURE_RATIO, 84 "sra-field-structure-ratio", 85 "The threshold ratio between instantiated fields and the total structure size", 86 75, 0, 100) 87 88/* The single function inlining limit. This is the maximum size 89 of a function counted in internal gcc instructions (not in 90 real machine instructions) that is eligible for inlining 91 by the tree inliner. 92 The default value is 450. 93 Only functions marked inline (or methods defined in the class 94 definition for C++) are affected by this. 95 There are more restrictions to inlining: If inlined functions 96 call other functions, the already inlined instructions are 97 counted and once the recursive inline limit (see 98 "max-inline-insns" parameter) is exceeded, the acceptable size 99 gets decreased. */ 100DEFPARAM (PARAM_MAX_INLINE_INSNS_SINGLE, 101 "max-inline-insns-single", 102 "The maximum number of instructions in a single function eligible for inlining", 103 450, 0, 0) 104 105/* The single function inlining limit for functions that are 106 inlined by virtue of -finline-functions (-O3). 107 This limit should be chosen to be below or equal to the limit 108 that is applied to functions marked inlined (or defined in the 109 class declaration in C++) given by the "max-inline-insns-single" 110 parameter. 111 The default value is 90. */ 112DEFPARAM (PARAM_MAX_INLINE_INSNS_AUTO, 113 "max-inline-insns-auto", 114 "The maximum number of instructions when automatically inlining", 115 90, 0, 0) 116 117DEFPARAM (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 122DEFPARAM (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 127DEFPARAM (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 132DEFPARAM (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 137DEFPARAM (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY, 138 "min-inline-recursive-probability", 139 "Inline recursively only when the probability of call being executed exceeds the parameter", 140 10, 0, 0) 141 142/* Limit the number of expansions created by the variable expansion 143 optimization to avoid register pressure. */ 144DEFPARAM (PARAM_MAX_VARIABLE_EXPANSIONS, 145 "max-variable-expansions-in-unroller", 146 "If -fvariable-expansion-in-unroller is used, the maximum number of times that an individual variable will be expanded during loop unrolling", 147 1, 0, 0) 148 149/* The maximum number of instructions to consider when looking for an 150 instruction to fill a delay slot. If more than this arbitrary 151 number of instructions is searched, the time savings from filling 152 the delay slot will be minimal so stop searching. Increasing 153 values mean more aggressive optimization, making the compile time 154 increase with probably small improvement in executable run time. */ 155DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH, 156 "max-delay-slot-insn-search", 157 "The maximum number of instructions to consider to fill a delay slot", 158 100, 0, 0) 159 160/* When trying to fill delay slots, the maximum number of instructions 161 to consider when searching for a block with valid live register 162 information. Increasing this arbitrarily chosen value means more 163 aggressive optimization, increasing the compile time. This 164 parameter should be removed when the delay slot code is rewritten 165 to maintain the control-flow graph. */ 166DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH, 167 "max-delay-slot-live-search", 168 "The maximum number of instructions to consider to find accurate live register information", 169 333, 0, 0) 170 171/* This parameter limits the number of branch elements that the 172 scheduler will track anti-dependencies through without resetting 173 the tracking mechanism. Large functions with few calls or barriers 174 can generate lists containing many 1000's of dependencies. Generally 175 the compiler either uses all available memory, or runs for far too long. */ 176DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH, 177 "max-pending-list-length", 178 "The maximum length of scheduling's pending operations list", 179 32, 0, 0) 180 181DEFPARAM(PARAM_LARGE_FUNCTION_INSNS, 182 "large-function-insns", 183 "The size of function body to be considered large", 184 2700, 0, 0) 185DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH, 186 "large-function-growth", 187 "Maximal growth due to inlining of large function (in percent)", 188 100, 0, 0) 189DEFPARAM(PARAM_LARGE_UNIT_INSNS, 190 "large-unit-insns", 191 "The size of translation unit to be considered large", 192 10000, 0, 0) 193DEFPARAM(PARAM_INLINE_UNIT_GROWTH, 194 "inline-unit-growth", 195 "how much can given compilation unit grow because of the inlining (in percent)", 196 50, 0, 0) 197DEFPARAM(PARAM_INLINE_CALL_COST, 198 "inline-call-cost", 199 "expense of call operation relative to ordinary arithmetic operations", 200 16, 0, 0) 201 202/* The GCSE optimization will be disabled if it would require 203 significantly more memory than this value. */ 204DEFPARAM(PARAM_MAX_GCSE_MEMORY, 205 "max-gcse-memory", 206 "The maximum amount of memory to be allocated by GCSE", 207 50 * 1024 * 1024, 0, 0) 208/* The number of repetitions of copy/const prop and PRE to run. */ 209DEFPARAM(PARAM_MAX_GCSE_PASSES, 210 "max-gcse-passes", 211 "The maximum number of passes to make when doing GCSE", 212 1, 1, 0) 213/* This is the threshold ratio when to perform partial redundancy 214 elimination after reload. We perform partial redundancy elimination 215 when the following holds: 216 (Redundant load execution count) 217 ------------------------------- >= GCSE_AFTER_RELOAD_PARTIAL_FRACTION 218 (Added loads execution count) */ 219DEFPARAM(PARAM_GCSE_AFTER_RELOAD_PARTIAL_FRACTION, 220 "gcse-after-reload-partial-fraction", 221 "The threshold ratio for performing partial redundancy elimination after reload", 222 3, 0, 0) 223/* This is the threshold ratio of the critical edges execution count compared to 224 the redundant loads execution count that permits performing the load 225 redundancy elimination in gcse after reload. */ 226DEFPARAM(PARAM_GCSE_AFTER_RELOAD_CRITICAL_FRACTION, 227 "gcse-after-reload-critical-fraction", 228 "The threshold ratio of critical edges execution count that permit performing redundancy elimination after reload", 229 10, 0, 0) 230/* This parameter limits the number of insns in a loop that will be unrolled, 231 and by how much the loop is unrolled. 232 233 This limit should be at most half of the peeling limits: loop unroller 234 decides to not unroll loops that iterate fewer than 2*number of allowed 235 unrollings and thus we would have loops that are neither peeled or unrolled 236 otherwise. */ 237DEFPARAM(PARAM_MAX_UNROLLED_INSNS, 238 "max-unrolled-insns", 239 "The maximum number of instructions to consider to unroll in a loop", 240 200, 0, 0) 241/* This parameter limits how many times the loop is unrolled depending 242 on number of insns really executed in each iteration. */ 243DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS, 244 "max-average-unrolled-insns", 245 "The maximum number of instructions to consider to unroll in a loop on average", 246 80, 0, 0) 247/* The maximum number of unrollings of a single loop. */ 248DEFPARAM(PARAM_MAX_UNROLL_TIMES, 249 "max-unroll-times", 250 "The maximum number of unrollings of a single loop", 251 8, 0, 0) 252/* The maximum number of insns of a peeled loop. */ 253DEFPARAM(PARAM_MAX_PEELED_INSNS, 254 "max-peeled-insns", 255 "The maximum number of insns of a peeled loop", 256 400, 0, 0) 257/* The maximum number of peelings of a single loop. */ 258DEFPARAM(PARAM_MAX_PEEL_TIMES, 259 "max-peel-times", 260 "The maximum number of peelings of a single loop", 261 16, 0, 0) 262/* The maximum number of insns of a peeled loop. */ 263DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS, 264 "max-completely-peeled-insns", 265 "The maximum number of insns of a completely peeled loop", 266 400, 0, 0) 267/* The maximum number of peelings of a single loop that is peeled completely. */ 268DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES, 269 "max-completely-peel-times", 270 "The maximum number of peelings of a single loop that is peeled completely", 271 16, 0, 0) 272/* The maximum number of insns of a peeled loop that rolls only once. */ 273DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS, 274 "max-once-peeled-insns", 275 "The maximum number of insns of a peeled loop that rolls only once", 276 400, 0, 0) 277 278/* The maximum number of insns of an unswitched loop. */ 279DEFPARAM(PARAM_MAX_UNSWITCH_INSNS, 280 "max-unswitch-insns", 281 "The maximum number of insns of an unswitched loop", 282 50, 0, 0) 283/* The maximum level of recursion in unswitch_single_loop. */ 284DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL, 285 "max-unswitch-level", 286 "The maximum number of unswitchings in a single loop", 287 3, 0, 0) 288 289/* The maximum number of iterations of a loop the brute force algorithm 290 for analysis of # of iterations of the loop tries to evaluate. */ 291DEFPARAM(PARAM_MAX_ITERATIONS_TO_TRACK, 292 "max-iterations-to-track", 293 "Bound on the number of iterations the brute force # of iterations analysis algorithm evaluates", 294 1000, 0, 0) 295/* A cutoff to avoid costly computations of the number of iterations in 296 the doloop transformation. */ 297DEFPARAM(PARAM_MAX_ITERATIONS_COMPUTATION_COST, 298 "max-iterations-computation-cost", 299 "Bound on the cost of an expression to compute the number of iterations", 300 10, 0, 0) 301 302DEFPARAM(PARAM_MAX_SMS_LOOP_NUMBER, 303 "max-sms-loop-number", 304 "Maximum number of loops to perform swing modulo scheduling on (mainly for debugging)", 305 -1, -1, -1) 306 307/* This parameter is used to tune SMS MAX II calculations. */ 308DEFPARAM(PARAM_SMS_MAX_II_FACTOR, 309 "sms-max-ii-factor", 310 "A factor for tuning the upper bound that swing modulo scheduler uses for scheduling a loop", 311 100, 0, 0) 312DEFPARAM(PARAM_SMS_DFA_HISTORY, 313 "sms-dfa-history", 314 "The number of cycles the swing modulo scheduler considers when checking conflicts using DFA", 315 0, 0, 0) 316DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD, 317 "sms-loop-average-count-threshold", 318 "A threshold on the average loop count considered by the swing modulo scheduler", 319 0, 0, 0) 320 321DEFPARAM(HOT_BB_COUNT_FRACTION, 322 "hot-bb-count-fraction", 323 "Select fraction of the maximal count of repetitions of basic block in program given basic block needs to have to be considered hot", 324 10000, 0, 0) 325DEFPARAM(HOT_BB_FREQUENCY_FRACTION, 326 "hot-bb-frequency-fraction", 327 "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot", 328 1000, 0, 0) 329 330/* For guessed profiles, the loops having unknown number of iterations 331 are predicted to iterate relatively few (10) times at average. 332 For functions containing one loop with large known number of iterations 333 and other loops having unbounded loops we would end up predicting all 334 the other loops cold that is not usually the case. So we need to artificially 335 flatten the profile. 336 337 We need to cut the maximal predicted iterations to large enough iterations 338 so the loop appears important, but safely within HOT_BB_COUNT_FRACTION 339 range. */ 340 341DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS, 342 "max-predicted-iterations", 343 "The maximum number of loop iterations we predict statically", 344 100, 0, 0) 345DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK, 346 "tracer-dynamic-coverage-feedback", 347 "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available", 348 95, 0, 100) 349DEFPARAM(TRACER_DYNAMIC_COVERAGE, 350 "tracer-dynamic-coverage", 351 "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available", 352 75, 0, 100) 353DEFPARAM(TRACER_MAX_CODE_GROWTH, 354 "tracer-max-code-growth", 355 "Maximal code growth caused by tail duplication (in percent)", 356 100, 0, 0) 357DEFPARAM(TRACER_MIN_BRANCH_RATIO, 358 "tracer-min-branch-ratio", 359 "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent)", 360 10, 0, 100) 361DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK, 362 "tracer-min-branch-probability-feedback", 363 "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available", 364 80, 0, 100) 365DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY, 366 "tracer-min-branch-probability", 367 "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available", 368 50, 0, 100) 369 370/* The maximum number of incoming edges to consider for crossjumping. */ 371DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES, 372 "max-crossjump-edges", 373 "The maximum number of incoming edges to consider for crossjumping", 374 100, 0, 0) 375 376/* The minimum number of matching instructions to consider for crossjumping. */ 377DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS, 378 "min-crossjump-insns", 379 "The minimum number of matching instructions to consider for crossjumping", 380 5, 0, 0) 381 382/* The maximum number expansion factor when copying basic blocks. */ 383DEFPARAM(PARAM_MAX_GROW_COPY_BB_INSNS, 384 "max-grow-copy-bb-insns", 385 "The maximum expansion factor when copying basic blocks", 386 8, 0, 0) 387 388/* The maximum number of insns to duplicate when unfactoring computed gotos. */ 389DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS, 390 "max-goto-duplication-insns", 391 "The maximum number of insns to duplicate when unfactoring computed gotos", 392 8, 0, 0) 393 394/* The maximum length of path considered in cse. */ 395DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH, 396 "max-cse-path-length", 397 "The maximum length of path considered in cse", 398 10, 0, 0) 399DEFPARAM(PARAM_MAX_CSE_INSNS, 400 "max-cse-insns", 401 "The maximum instructions CSE process before flushing", 402 1000, 0, 0) 403 404/* The cost of expression in loop invariant motion that is considered 405 expensive. */ 406DEFPARAM(PARAM_LIM_EXPENSIVE, 407 "lim-expensive", 408 "The minimum cost of an expensive expression in the loop invariant motion", 409 20, 0, 0) 410 411/* Bound on number of candidates for induction variables below that 412 all candidates are considered for each use in induction variable 413 optimizations. */ 414 415DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND, 416 "iv-consider-all-candidates-bound", 417 "Bound on number of candidates below that all candidates are considered in iv optimizations", 418 30, 0, 0) 419 420/* The induction variable optimizations give up on loops that contain more 421 induction variable uses. */ 422 423DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES, 424 "iv-max-considered-uses", 425 "Bound on number of iv uses in loop optimized in iv optimizations", 426 250, 0, 0) 427 428/* If there are at most this number of ivs in the set, try removing unnecessary 429 ivs from the set always. */ 430 431DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND, 432 "iv-always-prune-cand-set-bound", 433 "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization", 434 10, 0, 0) 435 436DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE, 437 "scev-max-expr-size", 438 "Bound on size of expressions used in the scalar evolutions analyzer", 439 20, 0, 0) 440 441DEFPARAM(PARAM_VECT_MAX_VERSION_CHECKS, 442 "vect-max-version-checks", 443 "Bound on number of runtime checks inserted by the vectorizer's loop versioning", 444 6, 0, 0) 445 446/* The product of the next two is used to decide whether or not to 447 use .GLOBAL_VAR. See tree-dfa.c. */ 448DEFPARAM(PARAM_GLOBAL_VAR_THRESHOLD, 449 "global-var-threshold", 450 "Given N calls and V call-clobbered vars in a function. Use .GLOBAL_VAR if NxV is larger than this limit", 451 500000, 0, 0) 452 453DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS, 454 "max-cselib-memory-locations", 455 "The maximum memory locations recorded by cselib", 456 500, 0, 0) 457DEFPARAM(PARAM_MAX_FLOW_MEMORY_LOCATIONS, 458 "max-flow-memory-locations", 459 "The maximum memory locations recorded by flow", 460 100, 0, 0) 461 462#ifdef ENABLE_GC_ALWAYS_COLLECT 463# define GGC_MIN_EXPAND_DEFAULT 0 464# define GGC_MIN_HEAPSIZE_DEFAULT 0 465#else 466# define GGC_MIN_EXPAND_DEFAULT 30 467# define GGC_MIN_HEAPSIZE_DEFAULT 4096 468#endif 469 470DEFPARAM(GGC_MIN_EXPAND, 471 "ggc-min-expand", 472 "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap", 473 GGC_MIN_EXPAND_DEFAULT, 0, 0) 474 475DEFPARAM(GGC_MIN_HEAPSIZE, 476 "ggc-min-heapsize", 477 "Minimum heap size before we start collecting garbage, in kilobytes", 478 GGC_MIN_HEAPSIZE_DEFAULT, 0, 0) 479 480#undef GGC_MIN_EXPAND_DEFAULT 481#undef GGC_MIN_HEAPSIZE_DEFAULT 482 483DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS, 484 "max-reload-search-insns", 485 "The maximum number of instructions to search backward when looking for equivalent reload", 486 100, 0, 0) 487 488DEFPARAM(PARAM_MAX_ALIASED_VOPS, 489 "max-aliased-vops", 490 "The maximum number of virtual operands allowed to represent aliases before triggering alias grouping", 491 500, 0, 0) 492 493DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS, 494 "max-sched-region-blocks", 495 "The maximum number of blocks in a region to be considered for interblock scheduling", 496 10, 0, 0) 497 498DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS, 499 "max-sched-region-insns", 500 "The maximum number of insns in a region to be considered for interblock scheduling", 501 100, 0, 0) 502 503DEFPARAM(PARAM_MIN_SPEC_PROB, 504 "min-spec-prob", 505 "The minimum probability of reaching a source block for interblock speculative scheduling", 506 40, 0, 0) 507 508DEFPARAM(PARAM_MAX_SCHED_EXTEND_REGIONS_ITERS, 509 "max-sched-extend-regions-iters", 510 "The maximum number of iterations through CFG to extend regions", 511 0, 0, 0) 512 513DEFPARAM(PARAM_MAX_SCHED_INSN_CONFLICT_DELAY, 514 "max-sched-insn-conflict-delay", 515 "The maximum conflict delay for an insn to be considered for speculative motion", 516 3, 1, 10) 517 518DEFPARAM(PARAM_SCHED_SPEC_PROB_CUTOFF, 519 "sched-spec-prob-cutoff", 520 "The minimal probability of speculation success (in percents), so that speculative insn will be scheduled.", 521 40, 0, 100) 522 523DEFPARAM(PARAM_MAX_LAST_VALUE_RTL, 524 "max-last-value-rtl", 525 "The maximum number of RTL nodes that can be recorded as combiner's last value", 526 10000, 0, 0) 527 528/* INTEGER_CST nodes are shared for values [{-1,0} .. N) for 529 {signed,unsigned} integral types. This determines N. 530 Experimentation shows 256 to be a good value. */ 531DEFPARAM (PARAM_INTEGER_SHARE_LIMIT, 532 "integer-share-limit", 533 "The upper bound for sharing integer constants", 534 256, 2, 2) 535 536/* Incremental SSA updates for virtual operands may be very slow if 537 there is a large number of mappings to process. In those cases, it 538 is faster to rewrite the virtual symbols from scratch as if they 539 had been recently introduced. This heuristic cannot be applied to 540 SSA mappings for real SSA names, only symbols kept in FUD chains. 541 542 PARAM_MIN_VIRTUAL_MAPPINGS specifies the minimum number of virtual 543 mappings that should be registered to trigger the heuristic. 544 545 PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO specifies the ratio between 546 mappings and symbols. If the number of virtual mappings is 547 PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO bigger than the number of 548 virtual symbols to be updated, then the updater switches to a full 549 update for those symbols. */ 550DEFPARAM (PARAM_MIN_VIRTUAL_MAPPINGS, 551 "min-virtual-mappings", 552 "Minimum number of virtual mappings to consider switching to full virtual renames", 553 100, 0, 0) 554 555DEFPARAM (PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO, 556 "virtual-mappings-ratio", 557 "Ratio between virtual mappings and virtual symbols to do full virtual renames", 558 3, 0, 0) 559 560DEFPARAM (PARAM_SSP_BUFFER_SIZE, 561 "ssp-buffer-size", 562 "The lower bound for a buffer to be considered for stack smashing protection", 563 8, 1, 0) 564 565/* When we thread through a block we have to make copies of the 566 statements within the block. Clearly for large blocks the code 567 duplication is bad. 568 569 PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number 570 of statements and PHI nodes allowed in a block which is going to 571 be duplicated for thread jumping purposes. 572 573 Some simple analysis showed that more than 99% of the jump 574 threading opportunities are for blocks with less than 15 575 statements. So we can get the benefits of jump threading 576 without excessive code bloat for pathological cases with the 577 throttle set at 15 statements. */ 578DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS, 579 "max-jump-thread-duplication-stmts", 580 "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps", 581 15, 0, 0) 582 583/* This is the maximum number of fields a variable may have before the pointer analysis machinery 584 will stop trying to treat it in a field-sensitive manner. 585 There are programs out there with thousands of fields per structure, and handling them 586 field-sensitively is not worth the cost. */ 587DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE, 588 "max-fields-for-field-sensitive", 589 "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable", 590 100, 0, 0) 591 592DEFPARAM(PARAM_MAX_SCHED_READY_INSNS, 593 "max-sched-ready-insns", 594 "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass", 595 100, 0, 0) 596 597/* 598Local variables: 599mode:c 600End: */ 601