2014-08-04 Ed Schonberg <schonberg@adacore.com>
[official-gcc.git] / gcc / params.def
blobcad00e222a5c69379e723d270447eed2e73d8913
1 /* params.def - Run-time parameters.
2 Copyright (C) 2001-2014 Free Software Foundation, Inc.
3 Written by Mark Mitchell <mark@codesourcery.com>.
5 This file is part of GCC.
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.
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.
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/>. */
21 /* This file contains definitions for language-independent
22 parameters. The DEFPARAM macro takes 6 arguments:
24 - The enumeral corresponding to this parameter.
26 - The name that can be used to set this parameter using the
27 command-line option `--param <name>=<value>'.
29 - A help string explaining how the parameter is used.
31 - A default value for the parameter.
33 - The minimum acceptable value for the parameter.
35 - The maximum acceptable value for the parameter (if greater than
36 the minimum).
38 Be sure to add an entry to invoke.texi summarizing the parameter. */
40 /* When branch is predicted to be taken with probability lower than this
41 threshold (in percent), then it is considered well predictable. */
42 DEFPARAM (PARAM_PREDICTABLE_BRANCH_OUTCOME,
43 "predictable-branch-outcome",
44 "Maximal estimated outcome of branch considered predictable",
45 2, 0, 50)
47 DEFPARAM (PARAM_INLINE_MIN_SPEEDUP,
48 "inline-min-speedup",
49 "The minimal estimated speedup allowing inliner to ignore inline-insns-single and inline-isnsns-auto",
50 10, 0, 0)
52 /* The single function inlining limit. This is the maximum size
53 of a function counted in internal gcc instructions (not in
54 real machine instructions) that is eligible for inlining
55 by the tree inliner.
56 The default value is 450.
57 Only functions marked inline (or methods defined in the class
58 definition for C++) are affected by this.
59 There are more restrictions to inlining: If inlined functions
60 call other functions, the already inlined instructions are
61 counted and once the recursive inline limit (see
62 "max-inline-insns" parameter) is exceeded, the acceptable size
63 gets decreased. */
64 DEFPARAM (PARAM_MAX_INLINE_INSNS_SINGLE,
65 "max-inline-insns-single",
66 "The maximum number of instructions in a single function eligible for inlining",
67 400, 0, 0)
69 /* The single function inlining limit for functions that are
70 inlined by virtue of -finline-functions (-O3).
71 This limit should be chosen to be below or equal to the limit
72 that is applied to functions marked inlined (or defined in the
73 class declaration in C++) given by the "max-inline-insns-single"
74 parameter.
75 The default value is 40. */
76 DEFPARAM (PARAM_MAX_INLINE_INSNS_AUTO,
77 "max-inline-insns-auto",
78 "The maximum number of instructions when automatically inlining",
79 40, 0, 0)
81 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE,
82 "max-inline-insns-recursive",
83 "The maximum number of instructions inline function can grow to via recursive inlining",
84 450, 0, 0)
86 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO,
87 "max-inline-insns-recursive-auto",
88 "The maximum number of instructions non-inline function can grow to via recursive inlining",
89 450, 0, 0)
91 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH,
92 "max-inline-recursive-depth",
93 "The maximum depth of recursive inlining for inline functions",
94 8, 0, 0)
96 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO,
97 "max-inline-recursive-depth-auto",
98 "The maximum depth of recursive inlining for non-inline functions",
99 8, 0, 0)
101 DEFPARAM (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY,
102 "min-inline-recursive-probability",
103 "Inline recursively only when the probability of call being executed exceeds the parameter",
104 10, 0, 0)
106 /* Limit of iterations of early inliner. This basically bounds number of
107 nested indirect calls early inliner can resolve. Deeper chains are still
108 handled by late inlining. */
109 DEFPARAM (PARAM_EARLY_INLINER_MAX_ITERATIONS,
110 "max-early-inliner-iterations",
111 "The maximum number of nested indirect inlining performed by early inliner",
112 1, 0, 0)
114 /* Limit on probability of entry BB. */
115 DEFPARAM (PARAM_COMDAT_SHARING_PROBABILITY,
116 "comdat-sharing-probability",
117 "Probability that COMDAT function will be shared with different compilation unit",
118 20, 0, 0)
120 /* Limit on probability of entry BB. */
121 DEFPARAM (PARAM_PARTIAL_INLINING_ENTRY_PROBABILITY,
122 "partial-inlining-entry-probability",
123 "Maximum probability of the entry BB of split region (in percent relative to entry BB of the function) to make partial inlining happen",
124 70, 0, 0)
126 /* Limit the number of expansions created by the variable expansion
127 optimization to avoid register pressure. */
128 DEFPARAM (PARAM_MAX_VARIABLE_EXPANSIONS,
129 "max-variable-expansions-in-unroller",
130 "If -fvariable-expansion-in-unroller is used, the maximum number of times that an individual variable will be expanded during loop unrolling",
131 1, 0, 0)
133 /* Limit loop autovectorization to loops with large enough iteration count. */
134 DEFPARAM (PARAM_MIN_VECT_LOOP_BOUND,
135 "min-vect-loop-bound",
136 "If -ftree-vectorize is used, the minimal loop bound of a loop to be considered for vectorization",
137 1, 1, 0)
139 /* The maximum number of instructions to consider when looking for an
140 instruction to fill a delay slot. If more than this arbitrary
141 number of instructions is searched, the time savings from filling
142 the delay slot will be minimal so stop searching. Increasing
143 values mean more aggressive optimization, making the compile time
144 increase with probably small improvement in executable run time. */
145 DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH,
146 "max-delay-slot-insn-search",
147 "The maximum number of instructions to consider to fill a delay slot",
148 100, 0, 0)
150 /* When trying to fill delay slots, the maximum number of instructions
151 to consider when searching for a block with valid live register
152 information. Increasing this arbitrarily chosen value means more
153 aggressive optimization, increasing the compile time. This
154 parameter should be removed when the delay slot code is rewritten
155 to maintain the control-flow graph. */
156 DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH,
157 "max-delay-slot-live-search",
158 "The maximum number of instructions to consider to find accurate live register information",
159 333, 0, 0)
161 /* This parameter limits the number of branch elements that the
162 scheduler will track anti-dependencies through without resetting
163 the tracking mechanism. Large functions with few calls or barriers
164 can generate lists containing many 1000's of dependencies. Generally
165 the compiler either uses all available memory, or runs for far too long. */
166 DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH,
167 "max-pending-list-length",
168 "The maximum length of scheduling's pending operations list",
169 32, 0, 0)
171 /* This parameter limits the number of backtracking attempts when using the
172 haifa scheduler for modulo scheduling. */
173 DEFPARAM(PARAM_MAX_MODULO_BACKTRACK_ATTEMPTS,
174 "max-modulo-backtrack-attempts",
175 "The maximum number of backtrack attempts the scheduler should make when modulo scheduling a loop",
176 40, 0, 0)
178 DEFPARAM(PARAM_LARGE_FUNCTION_INSNS,
179 "large-function-insns",
180 "The size of function body to be considered large",
181 2700, 0, 0)
182 DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH,
183 "large-function-growth",
184 "Maximal growth due to inlining of large function (in percent)",
185 100, 0, 0)
186 DEFPARAM(PARAM_LARGE_UNIT_INSNS,
187 "large-unit-insns",
188 "The size of translation unit to be considered large",
189 10000, 0, 0)
190 DEFPARAM(PARAM_INLINE_UNIT_GROWTH,
191 "inline-unit-growth",
192 "How much can given compilation unit grow because of the inlining (in percent)",
193 30, 0, 0)
194 DEFPARAM(PARAM_IPCP_UNIT_GROWTH,
195 "ipcp-unit-growth",
196 "How much can given compilation unit grow because of the interprocedural constant propagation (in percent)",
197 10, 0, 0)
198 DEFPARAM(PARAM_EARLY_INLINING_INSNS,
199 "early-inlining-insns",
200 "Maximal estimated growth of function body caused by early inlining of single call",
201 11, 0, 0)
202 DEFPARAM(PARAM_LARGE_STACK_FRAME,
203 "large-stack-frame",
204 "The size of stack frame to be considered large",
205 256, 0, 0)
206 DEFPARAM(PARAM_STACK_FRAME_GROWTH,
207 "large-stack-frame-growth",
208 "Maximal stack frame growth due to inlining (in percent)",
209 1000, 0, 0)
211 /* The GCSE optimization will be disabled if it would require
212 significantly more memory than this value. */
213 DEFPARAM(PARAM_MAX_GCSE_MEMORY,
214 "max-gcse-memory",
215 "The maximum amount of memory to be allocated by GCSE",
216 50 * 1024 * 1024, 0, 0)
218 /* The GCSE optimization of an expression will avoided if the ratio of
219 insertions to deletions is greater than this value. */
220 DEFPARAM(PARAM_MAX_GCSE_INSERTION_RATIO,
221 "max-gcse-insertion-ratio",
222 "The maximum ratio of insertions to deletions of expressions in GCSE",
223 20, 0, 0)
225 /* This is the threshold ratio when to perform partial redundancy
226 elimination after reload. We perform partial redundancy elimination
227 when the following holds:
228 (Redundant load execution count)
229 ------------------------------- >= GCSE_AFTER_RELOAD_PARTIAL_FRACTION
230 (Added loads execution count) */
231 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_PARTIAL_FRACTION,
232 "gcse-after-reload-partial-fraction",
233 "The threshold ratio for performing partial redundancy elimination after reload",
234 3, 0, 0)
235 /* This is the threshold ratio of the critical edges execution count compared to
236 the redundant loads execution count that permits performing the load
237 redundancy elimination in gcse after reload. */
238 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_CRITICAL_FRACTION,
239 "gcse-after-reload-critical-fraction",
240 "The threshold ratio of critical edges execution count that permit performing redundancy elimination after reload",
241 10, 0, 0)
243 /* GCSE will use GCSE_COST_DISTANCE_RATION as a scaling factor
244 to calculate maximum distance for which an expression is allowed to move
245 from its rtx_cost. */
246 DEFPARAM(PARAM_GCSE_COST_DISTANCE_RATIO,
247 "gcse-cost-distance-ratio",
248 "Scaling factor in calculation of maximum distance an expression can be moved by GCSE optimizations",
249 10, 0, 0)
250 /* GCSE won't restrict distance for which an expression with rtx_cost greater
251 than COSTS_N_INSN(GCSE_UNRESTRICTED_COST) is allowed to move. */
252 DEFPARAM(PARAM_GCSE_UNRESTRICTED_COST,
253 "gcse-unrestricted-cost",
254 "Cost at which GCSE optimizations will not constraint the distance an expression can travel",
255 3, 0, 0)
257 /* How deep from a given basic block the dominator tree should be searched
258 for expressions to hoist to the block. The value of 0 will avoid limiting
259 the search. */
260 DEFPARAM(PARAM_MAX_HOIST_DEPTH,
261 "max-hoist-depth",
262 "Maximum depth of search in the dominator tree for expressions to hoist",
263 30, 0, 0)
265 /* This parameter limits the number of insns in a loop that will be unrolled,
266 and by how much the loop is unrolled.
268 This limit should be at most half of the peeling limits: loop unroller
269 decides to not unroll loops that iterate fewer than 2*number of allowed
270 unrollings and thus we would have loops that are neither peeled or unrolled
271 otherwise. */
272 DEFPARAM(PARAM_MAX_UNROLLED_INSNS,
273 "max-unrolled-insns",
274 "The maximum number of instructions to consider to unroll in a loop",
275 200, 0, 0)
276 /* This parameter limits how many times the loop is unrolled depending
277 on number of insns really executed in each iteration. */
278 DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS,
279 "max-average-unrolled-insns",
280 "The maximum number of instructions to consider to unroll in a loop on average",
281 80, 0, 0)
282 /* The maximum number of unrollings of a single loop. */
283 DEFPARAM(PARAM_MAX_UNROLL_TIMES,
284 "max-unroll-times",
285 "The maximum number of unrollings of a single loop",
286 8, 0, 0)
287 /* The maximum number of insns of a peeled loop. */
288 DEFPARAM(PARAM_MAX_PEELED_INSNS,
289 "max-peeled-insns",
290 "The maximum number of insns of a peeled loop",
291 100, 0, 0)
292 /* The maximum number of peelings of a single loop. */
293 DEFPARAM(PARAM_MAX_PEEL_TIMES,
294 "max-peel-times",
295 "The maximum number of peelings of a single loop",
296 16, 0, 0)
297 /* The maximum number of peelings of a single loop that is peeled completely. */
298 DEFPARAM(PARAM_MAX_PEEL_BRANCHES,
299 "max-peel-branches",
300 "The maximum number of branches on the path through the peeled sequence",
301 32, 0, 0)
302 /* The maximum number of insns of a peeled loop. */
303 DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS,
304 "max-completely-peeled-insns",
305 "The maximum number of insns of a completely peeled loop",
306 100, 0, 0)
307 /* The maximum number of peelings of a single loop that is peeled completely. */
308 DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES,
309 "max-completely-peel-times",
310 "The maximum number of peelings of a single loop that is peeled completely",
311 16, 0, 0)
312 /* The maximum number of insns of a peeled loop that rolls only once. */
313 DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS,
314 "max-once-peeled-insns",
315 "The maximum number of insns of a peeled loop that rolls only once",
316 400, 0, 0)
317 /* The maximum depth of a loop nest we completely peel. */
318 DEFPARAM(PARAM_MAX_UNROLL_ITERATIONS,
319 "max-completely-peel-loop-nest-depth",
320 "The maximum depth of a loop nest we completely peel",
321 8, 0, 0)
323 /* The maximum number of insns of an unswitched loop. */
324 DEFPARAM(PARAM_MAX_UNSWITCH_INSNS,
325 "max-unswitch-insns",
326 "The maximum number of insns of an unswitched loop",
327 50, 0, 0)
328 /* The maximum level of recursion in unswitch_single_loop. */
329 DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL,
330 "max-unswitch-level",
331 "The maximum number of unswitchings in a single loop",
332 3, 0, 0)
334 /* The maximum number of iterations of a loop the brute force algorithm
335 for analysis of # of iterations of the loop tries to evaluate. */
336 DEFPARAM(PARAM_MAX_ITERATIONS_TO_TRACK,
337 "max-iterations-to-track",
338 "Bound on the number of iterations the brute force # of iterations analysis algorithm evaluates",
339 1000, 0, 0)
340 /* A cutoff to avoid costly computations of the number of iterations in
341 the doloop transformation. */
342 DEFPARAM(PARAM_MAX_ITERATIONS_COMPUTATION_COST,
343 "max-iterations-computation-cost",
344 "Bound on the cost of an expression to compute the number of iterations",
345 10, 0, 0)
347 /* This parameter is used to tune SMS MAX II calculations. */
348 DEFPARAM(PARAM_SMS_MAX_II_FACTOR,
349 "sms-max-ii-factor",
350 "A factor for tuning the upper bound that swing modulo scheduler uses for scheduling a loop",
351 100, 0, 0)
352 /* The minimum value of stage count that swing modulo scheduler will generate. */
353 DEFPARAM(PARAM_SMS_MIN_SC,
354 "sms-min-sc",
355 "The minimum value of stage count that swing modulo scheduler will generate.",
356 2, 1, 1)
357 DEFPARAM(PARAM_SMS_DFA_HISTORY,
358 "sms-dfa-history",
359 "The number of cycles the swing modulo scheduler considers when checking conflicts using DFA",
360 0, 0, 0)
361 DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD,
362 "sms-loop-average-count-threshold",
363 "A threshold on the average loop count considered by the swing modulo scheduler",
364 0, 0, 0)
366 DEFPARAM(HOT_BB_COUNT_WS_PERMILLE,
367 "hot-bb-count-ws-permille",
368 "A basic block profile count is considered hot if it contributes to "
369 "the given permillage of the entire profiled execution",
370 999, 0, 1000)
371 DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
372 "hot-bb-frequency-fraction",
373 "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot",
374 1000, 0, 0)
376 DEFPARAM(UNLIKELY_BB_COUNT_FRACTION,
377 "unlikely-bb-count-fraction",
378 "The minimum fraction of profile runs a given basic block execution count must be not to be considered unlikely",
379 20, 1, 10000)
381 DEFPARAM (PARAM_ALIGN_THRESHOLD,
382 "align-threshold",
383 "Select fraction of the maximal frequency of executions of basic block in function given basic block get alignment",
384 100, 1, 0)
386 DEFPARAM (PARAM_ALIGN_LOOP_ITERATIONS,
387 "align-loop-iterations",
388 "Loops iterating at least selected number of iterations will get loop alignement.",
389 4, 0, 0)
391 /* For guessed profiles, the loops having unknown number of iterations
392 are predicted to iterate relatively few (10) times at average.
393 For functions containing one loop with large known number of iterations
394 and other loops having unbounded loops we would end up predicting all
395 the other loops cold that is not usually the case. So we need to artificially
396 flatten the profile.
398 We need to cut the maximal predicted iterations to large enough iterations
399 so the loop appears important, but safely within maximum hotness
400 range. */
402 DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS,
403 "max-predicted-iterations",
404 "The maximum number of loop iterations we predict statically",
405 100, 0, 0)
407 /* This parameter controls the probability of builtin_expect. The default
408 value is 90%. This empirical value is obtained through the weighted
409 probability of FDO counters (with the FDO count value as the weight)
410 in some real world programs:
411 (1) Google performance test benchmarks: the probability is 0.9081.
412 (2) Linux 3.3 kernel running Google search workload: the probability
413 is 0.8717. */
415 DEFPARAM(BUILTIN_EXPECT_PROBABILITY,
416 "builtin-expect-probability",
417 "Set the estimated probability in percentage for builtin expect. The default value is 90% probability.",
418 90, 0, 100)
419 DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
420 "tracer-dynamic-coverage-feedback",
421 "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available",
422 95, 0, 100)
423 DEFPARAM(TRACER_DYNAMIC_COVERAGE,
424 "tracer-dynamic-coverage",
425 "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available",
426 75, 0, 100)
427 DEFPARAM(TRACER_MAX_CODE_GROWTH,
428 "tracer-max-code-growth",
429 "Maximal code growth caused by tail duplication (in percent)",
430 100, 0, 0)
431 DEFPARAM(TRACER_MIN_BRANCH_RATIO,
432 "tracer-min-branch-ratio",
433 "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent)",
434 10, 0, 100)
435 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
436 "tracer-min-branch-probability-feedback",
437 "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available",
438 80, 0, 100)
439 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
440 "tracer-min-branch-probability",
441 "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available",
442 50, 0, 100)
444 /* The maximum number of incoming edges to consider for crossjumping. */
445 DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
446 "max-crossjump-edges",
447 "The maximum number of incoming edges to consider for crossjumping",
448 100, 0, 0)
450 /* The minimum number of matching instructions to consider for crossjumping. */
451 DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS,
452 "min-crossjump-insns",
453 "The minimum number of matching instructions to consider for crossjumping",
454 5, 1, 0)
456 /* The maximum number expansion factor when copying basic blocks. */
457 DEFPARAM(PARAM_MAX_GROW_COPY_BB_INSNS,
458 "max-grow-copy-bb-insns",
459 "The maximum expansion factor when copying basic blocks",
460 8, 0, 0)
462 /* The maximum number of insns to duplicate when unfactoring computed gotos. */
463 DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS,
464 "max-goto-duplication-insns",
465 "The maximum number of insns to duplicate when unfactoring computed gotos",
466 8, 0, 0)
468 /* The maximum length of path considered in cse. */
469 DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
470 "max-cse-path-length",
471 "The maximum length of path considered in cse",
472 10, 1, 0)
473 DEFPARAM(PARAM_MAX_CSE_INSNS,
474 "max-cse-insns",
475 "The maximum instructions CSE process before flushing",
476 1000, 0, 0)
478 /* The cost of expression in loop invariant motion that is considered
479 expensive. */
480 DEFPARAM(PARAM_LIM_EXPENSIVE,
481 "lim-expensive",
482 "The minimum cost of an expensive expression in the loop invariant motion",
483 20, 0, 0)
485 /* Bound on number of candidates for induction variables below that
486 all candidates are considered for each use in induction variable
487 optimizations. */
489 DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND,
490 "iv-consider-all-candidates-bound",
491 "Bound on number of candidates below that all candidates are considered in iv optimizations",
492 30, 0, 0)
494 /* The induction variable optimizations give up on loops that contain more
495 induction variable uses. */
497 DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES,
498 "iv-max-considered-uses",
499 "Bound on number of iv uses in loop optimized in iv optimizations",
500 250, 0, 0)
502 /* If there are at most this number of ivs in the set, try removing unnecessary
503 ivs from the set always. */
505 DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND,
506 "iv-always-prune-cand-set-bound",
507 "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization",
508 10, 0, 0)
510 DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE,
511 "scev-max-expr-size",
512 "Bound on size of expressions used in the scalar evolutions analyzer",
513 100, 0, 0)
515 DEFPARAM(PARAM_SCEV_MAX_EXPR_COMPLEXITY,
516 "scev-max-expr-complexity",
517 "Bound on the complexity of the expressions in the scalar evolutions analyzer",
518 10, 0, 0)
520 DEFPARAM(PARAM_OMEGA_MAX_VARS,
521 "omega-max-vars",
522 "Bound on the number of variables in Omega constraint systems",
523 128, 0, 0)
525 DEFPARAM(PARAM_OMEGA_MAX_GEQS,
526 "omega-max-geqs",
527 "Bound on the number of inequalities in Omega constraint systems",
528 256, 0, 0)
530 DEFPARAM(PARAM_OMEGA_MAX_EQS,
531 "omega-max-eqs",
532 "Bound on the number of equalities in Omega constraint systems",
533 128, 0, 0)
535 DEFPARAM(PARAM_OMEGA_MAX_WILD_CARDS,
536 "omega-max-wild-cards",
537 "Bound on the number of wild cards in Omega constraint systems",
538 18, 0, 0)
540 DEFPARAM(PARAM_OMEGA_HASH_TABLE_SIZE,
541 "omega-hash-table-size",
542 "Bound on the size of the hash table in Omega constraint systems",
543 550, 0, 0)
545 DEFPARAM(PARAM_OMEGA_MAX_KEYS,
546 "omega-max-keys",
547 "Bound on the number of keys in Omega constraint systems",
548 500, 0, 0)
550 DEFPARAM(PARAM_OMEGA_ELIMINATE_REDUNDANT_CONSTRAINTS,
551 "omega-eliminate-redundant-constraints",
552 "When set to 1, use expensive methods to eliminate all redundant constraints",
553 0, 0, 1)
555 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIGNMENT_CHECKS,
556 "vect-max-version-for-alignment-checks",
557 "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alignment check",
558 6, 0, 0)
560 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS,
561 "vect-max-version-for-alias-checks",
562 "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alias check",
563 10, 0, 0)
565 DEFPARAM(PARAM_VECT_MAX_PEELING_FOR_ALIGNMENT,
566 "vect-max-peeling-for-alignment",
567 "Max number of loop peels to enhancement alignment of data references in a loop",
568 -1, -1, 64)
570 DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS,
571 "max-cselib-memory-locations",
572 "The maximum memory locations recorded by cselib",
573 500, 0, 0)
575 #ifdef ENABLE_GC_ALWAYS_COLLECT
576 # define GGC_MIN_EXPAND_DEFAULT 0
577 # define GGC_MIN_HEAPSIZE_DEFAULT 0
578 #else
579 # define GGC_MIN_EXPAND_DEFAULT 30
580 # define GGC_MIN_HEAPSIZE_DEFAULT 4096
581 #endif
583 DEFPARAM(GGC_MIN_EXPAND,
584 "ggc-min-expand",
585 "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap",
586 GGC_MIN_EXPAND_DEFAULT, 0, 0)
588 DEFPARAM(GGC_MIN_HEAPSIZE,
589 "ggc-min-heapsize",
590 "Minimum heap size before we start collecting garbage, in kilobytes",
591 GGC_MIN_HEAPSIZE_DEFAULT, 0, 0)
593 #undef GGC_MIN_EXPAND_DEFAULT
594 #undef GGC_MIN_HEAPSIZE_DEFAULT
596 DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
597 "max-reload-search-insns",
598 "The maximum number of instructions to search backward when looking for equivalent reload",
599 100, 0, 0)
601 DEFPARAM(PARAM_SINK_FREQUENCY_THRESHOLD,
602 "sink-frequency-threshold",
603 "Target block's relative execution frequency (as a percentage) required to sink a statement",
604 75, 0, 100)
606 DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS,
607 "max-sched-region-blocks",
608 "The maximum number of blocks in a region to be considered for interblock scheduling",
609 10, 0, 0)
611 DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS,
612 "max-sched-region-insns",
613 "The maximum number of insns in a region to be considered for interblock scheduling",
614 100, 0, 0)
616 DEFPARAM(PARAM_MAX_PIPELINE_REGION_BLOCKS,
617 "max-pipeline-region-blocks",
618 "The maximum number of blocks in a region to be considered for interblock scheduling",
619 15, 0, 0)
621 DEFPARAM(PARAM_MAX_PIPELINE_REGION_INSNS,
622 "max-pipeline-region-insns",
623 "The maximum number of insns in a region to be considered for interblock scheduling",
624 200, 0, 0)
626 DEFPARAM(PARAM_MIN_SPEC_PROB,
627 "min-spec-prob",
628 "The minimum probability of reaching a source block for interblock speculative scheduling",
629 40, 0, 0)
631 DEFPARAM(PARAM_MAX_SCHED_EXTEND_REGIONS_ITERS,
632 "max-sched-extend-regions-iters",
633 "The maximum number of iterations through CFG to extend regions",
634 0, 0, 0)
636 DEFPARAM(PARAM_MAX_SCHED_INSN_CONFLICT_DELAY,
637 "max-sched-insn-conflict-delay",
638 "The maximum conflict delay for an insn to be considered for speculative motion",
639 3, 1, 10)
641 DEFPARAM(PARAM_SCHED_SPEC_PROB_CUTOFF,
642 "sched-spec-prob-cutoff",
643 "The minimal probability of speculation success (in percents), so that speculative insn will be scheduled.",
644 40, 0, 100)
646 DEFPARAM(PARAM_SCHED_STATE_EDGE_PROB_CUTOFF,
647 "sched-state-edge-prob-cutoff",
648 "The minimum probability an edge must have for the scheduler to save its state across it.",
649 10, 0, 100)
651 DEFPARAM(PARAM_SELSCHED_MAX_LOOKAHEAD,
652 "selsched-max-lookahead",
653 "The maximum size of the lookahead window of selective scheduling",
654 50, 0, 0)
656 DEFPARAM(PARAM_SELSCHED_MAX_SCHED_TIMES,
657 "selsched-max-sched-times",
658 "Maximum number of times that an insn could be scheduled",
659 2, 0, 0)
661 DEFPARAM(PARAM_SELSCHED_INSNS_TO_RENAME,
662 "selsched-insns-to-rename",
663 "Maximum number of instructions in the ready list that are considered eligible for renaming",
664 2, 0, 0)
666 DEFPARAM (PARAM_SCHED_MEM_TRUE_DEP_COST,
667 "sched-mem-true-dep-cost",
668 "Minimal distance between possibly conflicting store and load",
669 1, 0, 0)
671 DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
672 "max-last-value-rtl",
673 "The maximum number of RTL nodes that can be recorded as combiner's last value",
674 10000, 0, 0)
676 DEFPARAM(PARAM_MAX_COMBINE_INSNS,
677 "max-combine-insns",
678 "The maximum number of insns combine tries to combine",
679 4, 2, 4)
681 /* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
682 {signed,unsigned} integral types. This determines N.
683 Experimentation shows 251 to be a good value that generates the
684 least amount of garbage for allocating the TREE_VEC storage. */
685 DEFPARAM (PARAM_INTEGER_SHARE_LIMIT,
686 "integer-share-limit",
687 "The upper bound for sharing integer constants",
688 251, 2, 2)
690 DEFPARAM (PARAM_SSP_BUFFER_SIZE,
691 "ssp-buffer-size",
692 "The lower bound for a buffer to be considered for stack smashing protection",
693 8, 1, 0)
695 DEFPARAM (PARAM_MIN_SIZE_FOR_STACK_SHARING,
696 "min-size-for-stack-sharing",
697 "The minimum size of variables taking part in stack slot sharing "
698 "when not optimizing",
699 32, 0, 0)
701 /* When we thread through a block we have to make copies of the
702 statements within the block. Clearly for large blocks the code
703 duplication is bad.
705 PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number
706 of statements and PHI nodes allowed in a block which is going to
707 be duplicated for thread jumping purposes.
709 Some simple analysis showed that more than 99% of the jump
710 threading opportunities are for blocks with less than 15
711 statements. So we can get the benefits of jump threading
712 without excessive code bloat for pathological cases with the
713 throttle set at 15 statements. */
714 DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS,
715 "max-jump-thread-duplication-stmts",
716 "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps",
717 15, 0, 0)
719 /* This is the maximum number of fields a variable may have before the pointer analysis machinery
720 will stop trying to treat it in a field-sensitive manner.
721 There are programs out there with thousands of fields per structure, and handling them
722 field-sensitively is not worth the cost. */
723 DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE,
724 "max-fields-for-field-sensitive",
725 "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable",
726 0, 0, 0)
728 DEFPARAM(PARAM_MAX_SCHED_READY_INSNS,
729 "max-sched-ready-insns",
730 "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass",
731 100, 0, 0)
733 /* This is the maximum number of active local stores RTL DSE will consider. */
734 DEFPARAM (PARAM_MAX_DSE_ACTIVE_LOCAL_STORES,
735 "max-dse-active-local-stores",
736 "Maximum number of active local stores in RTL dead store elimination",
737 5000, 0, 0)
739 /* Prefetching and cache-optimizations related parameters. Default values are
740 usually set by machine description. */
742 /* The number of insns executed before prefetch is completed. */
744 DEFPARAM (PARAM_PREFETCH_LATENCY,
745 "prefetch-latency",
746 "The number of insns executed before prefetch is completed",
747 200, 0, 0)
749 /* The number of prefetches that can run at the same time. */
751 DEFPARAM (PARAM_SIMULTANEOUS_PREFETCHES,
752 "simultaneous-prefetches",
753 "The number of prefetches that can run at the same time",
754 3, 0, 0)
756 /* The size of L1 cache in kB. */
758 DEFPARAM (PARAM_L1_CACHE_SIZE,
759 "l1-cache-size",
760 "The size of L1 cache",
761 64, 0, 0)
763 /* The size of L1 cache line in bytes. */
765 DEFPARAM (PARAM_L1_CACHE_LINE_SIZE,
766 "l1-cache-line-size",
767 "The size of L1 cache line",
768 32, 0, 0)
770 /* The size of L2 cache in kB. */
772 DEFPARAM (PARAM_L2_CACHE_SIZE,
773 "l2-cache-size",
774 "The size of L2 cache",
775 512, 0, 0)
777 /* Whether we should use canonical types rather than deep "structural"
778 type checking. Setting this value to 1 (the default) improves
779 compilation performance in the C++ and Objective-C++ front end;
780 this value should only be set to zero to work around bugs in the
781 canonical type system by disabling it. */
783 DEFPARAM (PARAM_USE_CANONICAL_TYPES,
784 "use-canonical-types",
785 "Whether to use canonical types",
786 1, 0, 1)
788 DEFPARAM (PARAM_MAX_PARTIAL_ANTIC_LENGTH,
789 "max-partial-antic-length",
790 "Maximum length of partial antic set when performing tree pre optimization",
791 100, 0, 0)
793 /* The following is used as a stop-gap limit for cases where really huge
794 SCCs blow up memory and compile-time use too much. If we hit this limit,
795 SCCVN and such FRE and PRE will be not done at all for the current
796 function. */
798 DEFPARAM (PARAM_SCCVN_MAX_SCC_SIZE,
799 "sccvn-max-scc-size",
800 "Maximum size of a SCC before SCCVN stops processing a function",
801 10000, 10, 0)
803 /* The following is used as a stop-gap limit for cases where really huge
804 functions blow up compile-time use too much. It limits the number of
805 alias-queries we do for finding common subexpressions for memory loads and
806 stores. The number of alias-queries is otherwise limited by the number of
807 stores on paths to function entry. */
809 DEFPARAM (PARAM_SCCVN_MAX_ALIAS_QUERIES_PER_ACCESS,
810 "sccvn-max-alias-queries-per-access",
811 "Maximum number of disambiguations to perform per memory access",
812 1000, 0, 0)
814 DEFPARAM (PARAM_IRA_MAX_LOOPS_NUM,
815 "ira-max-loops-num",
816 "Max loops number for regional RA",
817 100, 0, 0)
819 DEFPARAM (PARAM_IRA_MAX_CONFLICT_TABLE_SIZE,
820 "ira-max-conflict-table-size",
821 "Max size of conflict table in MB",
822 1000, 0, 0)
824 DEFPARAM (PARAM_IRA_LOOP_RESERVED_REGS,
825 "ira-loop-reserved-regs",
826 "The number of registers in each class kept unused by loop invariant motion",
827 2, 0, 0)
829 DEFPARAM (PARAM_LRA_MAX_CONSIDERED_RELOAD_PSEUDOS,
830 "lra-max-considered-reload-pseudos",
831 "The max number of reload pseudos which are considered during spilling a non-reload pseudo",
832 500, 0, 0)
834 /* Switch initialization conversion will refuse to create arrays that are
835 bigger than this parameter times the number of switch branches. */
837 DEFPARAM (PARAM_SWITCH_CONVERSION_BRANCH_RATIO,
838 "switch-conversion-max-branch-ratio",
839 "The maximum ratio between array size and switch branches for "
840 "a switch conversion to take place",
841 8, 1, 0)
843 /* Size of tiles when doing loop blocking. */
845 DEFPARAM (PARAM_LOOP_BLOCK_TILE_SIZE,
846 "loop-block-tile-size",
847 "size of tiles for loop blocking",
848 51, 0, 0)
850 /* Maximal number of parameters that we allow in a SCoP. */
852 DEFPARAM (PARAM_GRAPHITE_MAX_NB_SCOP_PARAMS,
853 "graphite-max-nb-scop-params",
854 "maximum number of parameters in a SCoP",
855 10, 0, 0)
857 /* Maximal number of basic blocks in the functions analyzed by Graphite. */
859 DEFPARAM (PARAM_GRAPHITE_MAX_BBS_PER_FUNCTION,
860 "graphite-max-bbs-per-function",
861 "maximum number of basic blocks per function to be analyzed by Graphite",
862 100, 0, 0)
864 /* Avoid data dependence analysis on very large loops. */
865 DEFPARAM (PARAM_LOOP_MAX_DATAREFS_FOR_DATADEPS,
866 "loop-max-datarefs-for-datadeps",
867 "Maximum number of datarefs in loop for building loop data dependencies",
868 1000, 0, 0)
870 /* Avoid doing loop invariant motion on very large loops. */
872 DEFPARAM (PARAM_LOOP_INVARIANT_MAX_BBS_IN_LOOP,
873 "loop-invariant-max-bbs-in-loop",
874 "Max basic blocks number in loop for loop invariant motion",
875 10000, 0, 0)
877 /* When the parameter is 1, use the internal function id
878 to look up for profile data. Otherwise, use a more stable
879 external id based on assembler name and source location. */
880 DEFPARAM (PARAM_PROFILE_FUNC_INTERNAL_ID,
881 "profile-func-internal-id",
882 "use internal function id in profile lookup",
883 0, 0, 1)
885 /* Avoid SLP vectorization of large basic blocks. */
886 DEFPARAM (PARAM_SLP_MAX_INSNS_IN_BB,
887 "slp-max-insns-in-bb",
888 "Maximum number of instructions in basic block to be considered for SLP vectorization",
889 1000, 0, 0)
891 DEFPARAM (PARAM_MIN_INSN_TO_PREFETCH_RATIO,
892 "min-insn-to-prefetch-ratio",
893 "Min. ratio of insns to prefetches to enable prefetching for "
894 "a loop with an unknown trip count",
895 9, 0, 0)
897 DEFPARAM (PARAM_PREFETCH_MIN_INSN_TO_MEM_RATIO,
898 "prefetch-min-insn-to-mem-ratio",
899 "Min. ratio of insns to mem ops to enable prefetching in a loop",
900 3, 0, 0)
902 /* Set maximum hash table size for var tracking. */
904 DEFPARAM (PARAM_MAX_VARTRACK_SIZE,
905 "max-vartrack-size",
906 "Max. size of var tracking hash tables",
907 50000000, 0, 0)
909 /* Set maximum recursion depth for var tracking expression expansion
910 and resolution. */
912 DEFPARAM (PARAM_MAX_VARTRACK_EXPR_DEPTH,
913 "max-vartrack-expr-depth",
914 "Max. recursion depth for expanding var tracking expressions",
915 12, 0, 0)
917 /* Set maximum length of value location list for which var tracking
918 should add reverse operations. */
920 DEFPARAM (PARAM_MAX_VARTRACK_REVERSE_OP_SIZE,
921 "max-vartrack-reverse-op-size",
922 "Max. size of loc list for which reverse ops should be added",
923 50, 0, 0)
925 /* Set minimum insn uid for non-debug insns. */
927 DEFPARAM (PARAM_MIN_NONDEBUG_INSN_UID,
928 "min-nondebug-insn-uid",
929 "The minimum UID to be used for a nondebug insn",
930 0, 1, 0)
932 DEFPARAM (PARAM_IPA_SRA_PTR_GROWTH_FACTOR,
933 "ipa-sra-ptr-growth-factor",
934 "Maximum allowed growth of size of new parameters ipa-sra replaces "
935 "a pointer to an aggregate with",
936 2, 0, 0)
938 DEFPARAM (PARAM_TM_MAX_AGGREGATE_SIZE,
939 "tm-max-aggregate-size",
940 "Size in bytes after which thread-local aggregates should be "
941 "instrumented with the logging functions instead of save/restore "
942 "pairs",
943 9, 0, 0)
945 DEFPARAM (PARAM_IPA_CP_VALUE_LIST_SIZE,
946 "ipa-cp-value-list-size",
947 "Maximum size of a list of values associated with each parameter for "
948 "interprocedural constant propagation",
949 8, 0, 0)
951 DEFPARAM (PARAM_IPA_CP_EVAL_THRESHOLD,
952 "ipa-cp-eval-threshold",
953 "Threshold ipa-cp opportunity evaluation that is still considered "
954 "beneficial to clone.",
955 500, 0, 0)
957 DEFPARAM (PARAM_IPA_MAX_AGG_ITEMS,
958 "ipa-max-agg-items",
959 "Maximum number of aggregate content items for a parameter in "
960 "jump functions and lattices",
961 16, 0, 0)
963 DEFPARAM (PARAM_IPA_CP_LOOP_HINT_BONUS,
964 "ipa-cp-loop-hint-bonus",
965 "Compile-time bonus IPA-CP assigns to candidates which make loop "
966 "bounds or strides known.",
967 64, 0, 0)
969 DEFPARAM (PARAM_IPA_CP_ARRAY_INDEX_HINT_BONUS,
970 "ipa-cp-array-index-hint-bonus",
971 "Compile-time bonus IPA-CP assigns to candidates which make an array "
972 "index known.",
973 48, 0, 0)
975 DEFPARAM (PARAM_IPA_MAX_AA_STEPS,
976 "ipa-max-aa-steps",
977 "Maximum number of statements that will be visited by IPA formal "
978 "parameter analysis based on alias analysis in any given function",
979 25000, 0, 0)
981 /* WHOPR partitioning configuration. */
983 DEFPARAM (PARAM_LTO_PARTITIONS,
984 "lto-partitions",
985 "Number of partitions the program should be split to",
986 32, 1, 0)
988 DEFPARAM (MIN_PARTITION_SIZE,
989 "lto-min-partition",
990 "Minimal size of a partition for LTO (in estimated instructions)",
991 1000, 0, 0)
993 /* Diagnostic parameters. */
995 DEFPARAM (CXX_MAX_NAMESPACES_FOR_DIAGNOSTIC_HELP,
996 "cxx-max-namespaces-for-diagnostic-help",
997 "Maximum number of namespaces to search for alternatives when "
998 "name lookup fails",
999 1000, 0, 0)
1001 /* Maximum number of conditional store pairs that can be sunk. */
1002 DEFPARAM (PARAM_MAX_STORES_TO_SINK,
1003 "max-stores-to-sink",
1004 "Maximum number of conditional store pairs that can be sunk",
1005 2, 0, 0)
1007 /* Override CASE_VALUES_THRESHOLD of when to switch from doing switch
1008 statements via if statements to using a table jump operation. If the value
1009 is 0, the default CASE_VALUES_THRESHOLD will be used. */
1010 DEFPARAM (PARAM_CASE_VALUES_THRESHOLD,
1011 "case-values-threshold",
1012 "The smallest number of different values for which it is best to "
1013 "use a jump-table instead of a tree of conditional branches, "
1014 "if 0, use the default for the machine",
1015 0, 0, 0)
1017 /* Data race flags for C++0x memory model compliance. */
1018 DEFPARAM (PARAM_ALLOW_STORE_DATA_RACES,
1019 "allow-store-data-races",
1020 "Allow new data races on stores to be introduced",
1021 0, 0, 1)
1023 /* Reassociation width to be used by tree reassoc optimization. */
1024 DEFPARAM (PARAM_TREE_REASSOC_WIDTH,
1025 "tree-reassoc-width",
1026 "Set the maximum number of instructions executed in parallel in "
1027 "reassociated tree. If 0, use the target dependent heuristic.",
1028 0, 0, 0)
1030 DEFPARAM (PARAM_MAX_TAIL_MERGE_COMPARISONS,
1031 "max-tail-merge-comparisons",
1032 "Maximum amount of similar bbs to compare a bb with",
1033 10, 0, 0)
1035 DEFPARAM (PARAM_MAX_TAIL_MERGE_ITERATIONS,
1036 "max-tail-merge-iterations",
1037 "Maximum amount of iterations of the pass over a function",
1038 2, 0, 0)
1040 /* Maximum number of strings for which strlen optimization pass will
1041 track string lenths. */
1042 DEFPARAM (PARAM_MAX_TRACKED_STRLENS,
1043 "max-tracked-strlens",
1044 "Maximum number of strings for which strlen optimization pass will "
1045 "track string lengths",
1046 1000, 0, 0)
1048 /* Keep this in sync with the sched_pressure_algorithm enum. */
1049 DEFPARAM (PARAM_SCHED_PRESSURE_ALGORITHM,
1050 "sched-pressure-algorithm",
1051 "Which -fsched-pressure algorithm to apply",
1052 1, 1, 2)
1054 /* Maximum length of candidate scans in straight-line strength reduction. */
1055 DEFPARAM (PARAM_MAX_SLSR_CANDIDATE_SCAN,
1056 "max-slsr-cand-scan",
1057 "Maximum length of candidate scans for straight-line "
1058 "strength reduction",
1059 50, 1, 999999)
1061 DEFPARAM (PARAM_ASAN_STACK,
1062 "asan-stack",
1063 "Enable asan stack protection",
1064 1, 0, 1)
1066 DEFPARAM (PARAM_ASAN_GLOBALS,
1067 "asan-globals",
1068 "Enable asan globals protection",
1069 1, 0, 1)
1071 DEFPARAM (PARAM_ASAN_INSTRUMENT_WRITES,
1072 "asan-instrument-writes",
1073 "Enable asan store operations protection",
1074 1, 0, 1)
1076 DEFPARAM (PARAM_ASAN_INSTRUMENT_READS,
1077 "asan-instrument-reads",
1078 "Enable asan load operations protection",
1079 1, 0, 1)
1081 DEFPARAM (PARAM_ASAN_MEMINTRIN,
1082 "asan-memintrin",
1083 "Enable asan builtin functions protection",
1084 1, 0, 1)
1086 DEFPARAM (PARAM_ASAN_USE_AFTER_RETURN,
1087 "asan-use-after-return",
1088 "Enable asan builtin functions protection",
1089 1, 0, 1)
1091 DEFPARAM (PARAM_ASAN_INSTRUMENTATION_WITH_CALL_THRESHOLD,
1092 "asan-instrumentation-with-call-threshold",
1093 "Use callbacks instead of inline code once number of accesses "
1094 " in function becomes greater or equal than this threshold",
1095 10000, 0, INT_MAX)
1097 DEFPARAM (PARAM_UNINIT_CONTROL_DEP_ATTEMPTS,
1098 "uninit-control-dep-attempts",
1099 "Maximum number of nested calls to search for control dependencies "
1100 "during uninitialized variable analysis",
1101 1000, 1, 0)
1104 Local variables:
1105 mode:c
1106 End: