1 /* params.def
- Run
-time parameters.
2 Copyright (C
) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
4 Free Software Foundation
, Inc.
5 Written by Mark Mitchell
<mark@codesourcery.com
>.
7 This file is part of GCC.
9 GCC is free software
; you can redistribute it and
/or modify it under
10 the terms of the GNU General Public License as published by the Free
11 Software Foundation
; either version
3, or (at your option
) any later
14 GCC is distributed in the hope that it will be useful
, but WITHOUT ANY
15 WARRANTY
; without even the implied warranty of MERCHANTABILITY or
16 FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License
19 You should have received a copy of the GNU General Public License
20 along with GCC
; see the file COPYING3. If not see
21 <http
://www.gnu.org
/licenses
/>.
*/
23 /* This file contains definitions for language
-independent
24 parameters. The DEFPARAM macro takes
6 arguments
:
26 - The enumeral corresponding to this parameter.
28 - The name that can be used to set this parameter using the
29 command
-line option `
--param
<name
>=<value
>'.
31 - A help string explaining how the parameter is used.
33 - A default value for the parameter.
35 - The minimum acceptable value for the parameter.
37 - The maximum acceptable value for the parameter (if greater than
40 Be sure to add an entry to invoke.texi summarizing the parameter. */
42 /* The threshold ratio between current and hottest structure counts.
43 We say that if the ratio of the current structure count,
44 calculated by profiling, to the hottest structure count
45 in the program is less than this parameter, then structure
46 reorganization is not applied. The default is 10%. */
47 DEFPARAM (PARAM_STRUCT_REORG_COLD_STRUCT_RATIO,
48 "struct-reorg-cold-struct-ratio",
49 "The threshold ratio between current and hottest structure counts",
52 /* When branch is predicted to be taken with probability lower than this
53 threshold (in percent), then it is considered well predictable. */
54 DEFPARAM (PARAM_PREDICTABLE_BRANCH_OUTCOME,
55 "predictable-branch-outcome",
56 "Maximal estimated outcome of branch considered predictable",
59 /* The single function inlining limit. This is the maximum size
60 of a function counted in internal gcc instructions (not in
61 real machine instructions) that is eligible for inlining
63 The default value is 450.
64 Only functions marked inline (or methods defined in the class
65 definition for C++) are affected by this.
66 There are more restrictions to inlining: If inlined functions
67 call other functions, the already inlined instructions are
68 counted and once the recursive inline limit (see
69 "max-inline-insns" parameter) is exceeded, the acceptable size
71 DEFPARAM (PARAM_MAX_INLINE_INSNS_SINGLE,
72 "max-inline-insns-single",
73 "The maximum number of instructions in a single function eligible for inlining",
76 /* The single function inlining limit for functions that are
77 inlined by virtue of -finline-functions (-O3).
78 This limit should be chosen to be below or equal to the limit
79 that is applied to functions marked inlined (or defined in the
80 class declaration in C++) given by the "max-inline-insns-single"
82 The default value is 40. */
83 DEFPARAM (PARAM_MAX_INLINE_INSNS_AUTO,
84 "max-inline-insns-auto",
85 "The maximum number of instructions when automatically inlining",
88 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE,
89 "max-inline-insns-recursive",
90 "The maximum number of instructions inline function can grow to via recursive inlining",
93 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO,
94 "max-inline-insns-recursive-auto",
95 "The maximum number of instructions non-inline function can grow to via recursive inlining",
98 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH,
99 "max-inline-recursive-depth",
100 "The maximum depth of recursive inlining for inline functions",
103 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO,
104 "max-inline-recursive-depth-auto",
105 "The maximum depth of recursive inlining for non-inline functions",
108 DEFPARAM (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY,
109 "min-inline-recursive-probability",
110 "Inline recursively only when the probability of call being executed exceeds the parameter",
113 DEFPARAM (PARAM_INLINE_FUNCTION_OVERHEAD_SIZE,
114 "inline-function-overhead-size",
115 "Size estimate of function overhead (prologue/epilogue) for inlining purposes",
118 /* Limit of iterations of early inliner. This basically bounds number of
119 nested indirect calls early inliner can resolve. Deeper chains are still
120 handled by late inlining. */
121 DEFPARAM (PARAM_EARLY_INLINER_MAX_ITERATIONS,
122 "max-early-inliner-iterations",
123 "The maximum number of nested indirect inlining performed by early inliner",
126 /* Limit on probability of entry BB. */
127 DEFPARAM (PARAM_COMDAT_SHARING_PROBABILITY,
128 "comdat-sharing-probability",
129 "Probability that COMDAT function will be shared with different compilatoin unit",
132 /* Limit on probability of entry BB. */
133 DEFPARAM (PARAM_PARTIAL_INLINING_ENTRY_PROBABILITY,
134 "partial-inlining-entry-probability",
135 "Maximum probability of the entry BB of split region (in percent relative to entry BB of the function) to make partial inlining happen",
138 /* Limit the number of expansions created by the variable expansion
139 optimization to avoid register pressure. */
140 DEFPARAM (PARAM_MAX_VARIABLE_EXPANSIONS,
141 "max-variable-expansions-in-unroller",
142 "If -fvariable-expansion-in-unroller is used, the maximum number of times that an individual variable will be expanded during loop unrolling",
145 /* Limit loop autovectorization to loops with large enough iteration count. */
146 DEFPARAM (PARAM_MIN_VECT_LOOP_BOUND,
147 "min-vect-loop-bound",
148 "If -ftree-vectorize is used, the minimal loop bound of a loop to be considered for vectorization",
151 /* The maximum number of instructions to consider when looking for an
152 instruction to fill a delay slot. If more than this arbitrary
153 number of instructions is searched, the time savings from filling
154 the delay slot will be minimal so stop searching. Increasing
155 values mean more aggressive optimization, making the compile time
156 increase with probably small improvement in executable run time. */
157 DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH,
158 "max-delay-slot-insn-search",
159 "The maximum number of instructions to consider to fill a delay slot",
162 /* When trying to fill delay slots, the maximum number of instructions
163 to consider when searching for a block with valid live register
164 information. Increasing this arbitrarily chosen value means more
165 aggressive optimization, increasing the compile time. This
166 parameter should be removed when the delay slot code is rewritten
167 to maintain the control-flow graph. */
168 DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH,
169 "max-delay-slot-live-search",
170 "The maximum number of instructions to consider to find accurate live register information",
173 /* This parameter limits the number of branch elements that the
174 scheduler will track anti-dependencies through without resetting
175 the tracking mechanism. Large functions with few calls or barriers
176 can generate lists containing many 1000's of dependencies. Generally
177 the compiler either uses all available memory
, or runs for far too long.
*/
178 DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH
,
179 "max-pending-list-length",
180 "The maximum length of scheduling's pending operations list",
183 DEFPARAM(PARAM_LARGE_FUNCTION_INSNS
,
184 "large-function-insns",
185 "The size of function body to be considered large",
187 DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH
,
188 "large-function-growth",
189 "Maximal growth due to inlining of large function (in percent)",
191 DEFPARAM(PARAM_LARGE_UNIT_INSNS
,
193 "The size of translation unit to be considered large",
195 DEFPARAM(PARAM_INLINE_UNIT_GROWTH
,
196 "inline-unit-growth",
197 "How much can given compilation unit grow because of the inlining (in percent)",
199 DEFPARAM(PARAM_IPCP_UNIT_GROWTH
,
201 "How much can given compilation unit grow because of the interprocedural constant propagation (in percent)",
203 DEFPARAM(PARAM_EARLY_INLINING_INSNS
,
204 "early-inlining-insns",
205 "Maximal estimated growth of function body caused by early inlining of single call",
207 DEFPARAM(PARAM_LARGE_STACK_FRAME
,
209 "The size of stack frame to be considered large",
211 DEFPARAM(PARAM_STACK_FRAME_GROWTH
,
212 "large-stack-frame-growth",
213 "Maximal stack frame growth due to inlining (in percent)",
216 /* The GCSE optimization will be disabled if it would require
217 significantly more memory than this value.
*/
218 DEFPARAM(PARAM_MAX_GCSE_MEMORY
,
220 "The maximum amount of memory to be allocated by GCSE",
221 50 * 1024 * 1024, 0, 0)
223 /* The GCSE optimization of an expression will avoided if the ratio of
224 insertions to deletions is greater than this value.
*/
225 DEFPARAM(PARAM_MAX_GCSE_INSERTION_RATIO
,
226 "max-gcse-insertion-ratio",
227 "The maximum ratio of insertions to deletions of expressions in GCSE",
230 /* This is the threshold ratio when to perform partial redundancy
231 elimination after reload. We perform partial redundancy elimination
232 when the following holds
:
233 (Redundant load execution count
)
234 ------------------------------- >= GCSE_AFTER_RELOAD_PARTIAL_FRACTION
235 (Added loads execution count
) */
236 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_PARTIAL_FRACTION
,
237 "gcse-after-reload-partial-fraction",
238 "The threshold ratio for performing partial redundancy elimination after reload",
240 /* This is the threshold ratio of the critical edges execution count compared to
241 the redundant loads execution count that permits performing the load
242 redundancy elimination in gcse after reload.
*/
243 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_CRITICAL_FRACTION
,
244 "gcse-after-reload-critical-fraction",
245 "The threshold ratio of critical edges execution count that permit performing redundancy elimination after reload",
248 /* GCSE will use GCSE_COST_DISTANCE_RATION as a scaling factor
249 to calculate maximum distance for which an expression is allowed to move
250 from its rtx_cost.
*/
251 DEFPARAM(PARAM_GCSE_COST_DISTANCE_RATIO
,
252 "gcse-cost-distance-ratio",
253 "Scaling factor in calculation of maximum distance an expression can be moved by GCSE optimizations",
255 /* GCSE won
't restrict distance for which an expression with rtx_cost greater
256 than COSTS_N_INSN(GCSE_UNRESTRICTED_COST) is allowed to move. */
257 DEFPARAM(PARAM_GCSE_UNRESTRICTED_COST,
258 "gcse-unrestricted-cost",
259 "Cost at which GCSE optimizations will not constraint the distance an expression can travel",
262 /* How deep from a given basic block the dominator tree should be searched
263 for expressions to hoist to the block. The value of 0 will avoid limiting
265 DEFPARAM(PARAM_MAX_HOIST_DEPTH,
267 "Maximum depth of search in the dominator tree for expressions to hoist",
270 /* This parameter limits the number of insns in a loop that will be unrolled,
271 and by how much the loop is unrolled.
273 This limit should be at most half of the peeling limits: loop unroller
274 decides to not unroll loops that iterate fewer than 2*number of allowed
275 unrollings and thus we would have loops that are neither peeled or unrolled
277 DEFPARAM(PARAM_MAX_UNROLLED_INSNS,
278 "max-unrolled-insns",
279 "The maximum number of instructions to consider to unroll in a loop",
281 /* This parameter limits how many times the loop is unrolled depending
282 on number of insns really executed in each iteration. */
283 DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS,
284 "max-average-unrolled-insns",
285 "The maximum number of instructions to consider to unroll in a loop on average",
287 /* The maximum number of unrollings of a single loop. */
288 DEFPARAM(PARAM_MAX_UNROLL_TIMES,
290 "The maximum number of unrollings of a single loop",
292 /* The maximum number of insns of a peeled loop. */
293 DEFPARAM(PARAM_MAX_PEELED_INSNS,
295 "The maximum number of insns of a peeled loop",
297 /* The maximum number of peelings of a single loop. */
298 DEFPARAM(PARAM_MAX_PEEL_TIMES,
300 "The maximum number of peelings of a single loop",
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",
307 /* The maximum number of insns of a peeled loop, when feedback
308 information is available. */
309 DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS_FEEDBACK,
310 "max-completely-peeled-insns-feedback",
311 "The maximum number of insns of a completely peeled loop when profile "
312 "feedback is available",
314 /* The maximum number of peelings of a single loop that is peeled completely. */
315 DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES,
316 "max-completely-peel-times",
317 "The maximum number of peelings of a single loop that is peeled completely",
319 /* The maximum number of peelings of a single loop that is peeled
320 completely, when feedback information is available. */
321 DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES_FEEDBACK,
322 "max-completely-peel-times-feedback",
323 "The maximum number of peelings of a single loop that is peeled "
324 "completely, when profile feedback is available",
326 /* The maximum number of insns of a peeled loop that rolls only once. */
327 DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS,
328 "max-once-peeled-insns",
329 "The maximum number of insns of a peeled loop that rolls only once",
331 /* The maximum number of insns of a peeled loop that rolls only once,
332 when feedback information is available. */
333 DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS_FEEDBACK,
334 "max-once-peeled-insns-feedback",
335 "The maximum number of insns of a peeled loop that rolls only once, "
336 "when profile feedback is available",
338 /* The maximum depth of a loop nest we completely peel. */
339 DEFPARAM(PARAM_MAX_UNROLL_ITERATIONS,
340 "max-completely-peel-loop-nest-depth",
341 "The maximum depth of a loop nest we completely peel",
343 /* The minimum profile count of basic blocks to look at when estimating
344 * the code size footprint of the call graph in a dynamic IPA compile. */
345 DEFPARAM(PARAM_CODESIZE_HOTNESS_THRESHOLD,
346 "codesize-hotness-threshold",
347 "Minimum profile count of basic blocks counted towards dynamic IPA "
348 "code size footprint estimate",
350 /* The maximum code size estimate under which loop unrolling and peeling
351 * is allowed in a dynamic IPA compile. This currently applies to loops with
352 * non-constant iteration counts and no floating point computations. */
353 DEFPARAM(PARAM_UNROLLPEEL_CODESIZE_THRESHOLD,
354 "unrollpeel-codesize-threshold",
355 "Maximum dynamic IPA code size footprint estimate for loop unrolling "
359 /* The maximum number of insns of an unswitched loop. */
360 DEFPARAM(PARAM_MAX_UNSWITCH_INSNS,
361 "max-unswitch-insns",
362 "The maximum number of insns of an unswitched loop",
364 /* The maximum level of recursion in unswitch_single_loop. */
365 DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL,
366 "max-unswitch-level",
367 "The maximum number of unswitchings in a single loop",
370 /* The maximum number of iterations of a loop the brute force algorithm
371 for analysis of # of iterations of the loop tries to evaluate. */
372 DEFPARAM(PARAM_MAX_ITERATIONS_TO_TRACK,
373 "max-iterations-to-track",
374 "Bound on the number of iterations the brute force # of iterations analysis algorithm evaluates",
376 /* A cutoff to avoid costly computations of the number of iterations in
377 the doloop transformation. */
378 DEFPARAM(PARAM_MAX_ITERATIONS_COMPUTATION_COST,
379 "max-iterations-computation-cost",
380 "Bound on the cost of an expression to compute the number of iterations",
383 /* This parameter is used to tune SMS MAX II calculations. */
384 DEFPARAM(PARAM_SMS_MAX_II_FACTOR,
386 "A factor for tuning the upper bound that swing modulo scheduler uses for scheduling a loop",
388 DEFPARAM(PARAM_SMS_DFA_HISTORY,
390 "The number of cycles the swing modulo scheduler considers when checking conflicts using DFA",
392 DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD,
393 "sms-loop-average-count-threshold",
394 "A threshold on the average loop count considered by the swing modulo scheduler",
397 DEFPARAM(HOT_BB_COUNT_FRACTION,
398 "hot-bb-count-fraction",
399 "Select fraction of the maximal count of repetitions of basic block in program given basic block needs to have to be considered hot",
401 DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
402 "hot-bb-frequency-fraction",
403 "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot",
406 DEFPARAM (PARAM_ALIGN_THRESHOLD,
408 "Select fraction of the maximal frequency of executions of basic block in function given basic block get alignment",
411 DEFPARAM (PARAM_ALIGN_LOOP_ITERATIONS,
412 "align-loop-iterations",
413 "Loops iterating at least selected number of iterations will get loop alignement.",
416 /* For guessed profiles, the loops having unknown number of iterations
417 are predicted to iterate relatively few (10) times at average.
418 For functions containing one loop with large known number of iterations
419 and other loops having unbounded loops we would end up predicting all
420 the other loops cold that is not usually the case. So we need to artificially
423 We need to cut the maximal predicted iterations to large enough iterations
424 so the loop appears important, but safely within HOT_BB_COUNT_FRACTION
427 DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS,
428 "max-predicted-iterations",
429 "The maximum number of loop iterations we predict statically",
431 DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
432 "tracer-dynamic-coverage-feedback",
433 "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available",
435 DEFPARAM(TRACER_DYNAMIC_COVERAGE,
436 "tracer-dynamic-coverage",
437 "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available",
439 DEFPARAM(TRACER_MAX_CODE_GROWTH,
440 "tracer-max-code-growth",
441 "Maximal code growth caused by tail duplication (in percent)",
443 DEFPARAM(TRACER_MIN_BRANCH_RATIO,
444 "tracer-min-branch-ratio",
445 "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent)",
447 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
448 "tracer-min-branch-probability-feedback",
449 "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available",
451 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
452 "tracer-min-branch-probability",
453 "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available",
456 /* The maximum number of incoming edges to consider for crossjumping. */
457 DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
458 "max-crossjump-edges",
459 "The maximum number of incoming edges to consider for crossjumping",
462 /* The minimum number of matching instructions to consider for crossjumping. */
463 DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS,
464 "min-crossjump-insns",
465 "The minimum number of matching instructions to consider for crossjumping",
468 /* The maximum number expansion factor when copying basic blocks. */
469 DEFPARAM(PARAM_MAX_GROW_COPY_BB_INSNS,
470 "max-grow-copy-bb-insns",
471 "The maximum expansion factor when copying basic blocks",
474 /* The maximum number of insns to duplicate when unfactoring computed gotos. */
475 DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS,
476 "max-goto-duplication-insns",
477 "The maximum number of insns to duplicate when unfactoring computed gotos",
480 /* The maximum length of path considered in cse. */
481 DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
482 "max-cse-path-length",
483 "The maximum length of path considered in cse",
485 DEFPARAM(PARAM_MAX_CSE_INSNS,
487 "The maximum instructions CSE process before flushing",
490 /* The cost of expression in loop invariant motion that is considered
492 DEFPARAM(PARAM_LIM_EXPENSIVE,
494 "The minimum cost of an expensive expression in the loop invariant motion",
497 /* Bound on number of candidates for induction variables below that
498 all candidates are considered for each use in induction variable
501 DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND,
502 "iv-consider-all-candidates-bound",
503 "Bound on number of candidates below that all candidates are considered in iv optimizations",
506 /* The induction variable optimizations give up on loops that contain more
507 induction variable uses. */
509 DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES,
510 "iv-max-considered-uses",
511 "Bound on number of iv uses in loop optimized in iv optimizations",
514 /* If there are at most this number of ivs in the set, try removing unnecessary
515 ivs from the set always. */
517 DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND,
518 "iv-always-prune-cand-set-bound",
519 "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization",
522 DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE,
523 "scev-max-expr-size",
524 "Bound on size of expressions used in the scalar evolutions analyzer",
527 DEFPARAM(PARAM_SCEV_MAX_EXPR_COMPLEXITY,
528 "scev-max-expr-complexity",
529 "Bound on the complexity of the expressions in the scalar evolutions analyzer",
532 DEFPARAM(PARAM_OMEGA_MAX_VARS,
534 "Bound on the number of variables in Omega constraint systems",
537 DEFPARAM(PARAM_OMEGA_MAX_GEQS,
539 "Bound on the number of inequalities in Omega constraint systems",
542 DEFPARAM(PARAM_OMEGA_MAX_EQS,
544 "Bound on the number of equalities in Omega constraint systems",
547 DEFPARAM(PARAM_OMEGA_MAX_WILD_CARDS,
548 "omega-max-wild-cards",
549 "Bound on the number of wild cards in Omega constraint systems",
552 DEFPARAM(PARAM_OMEGA_HASH_TABLE_SIZE,
553 "omega-hash-table-size",
554 "Bound on the size of the hash table in Omega constraint systems",
557 DEFPARAM(PARAM_OMEGA_MAX_KEYS,
559 "Bound on the number of keys in Omega constraint systems",
562 DEFPARAM(PARAM_OMEGA_ELIMINATE_REDUNDANT_CONSTRAINTS,
563 "omega-eliminate-redundant-constraints",
564 "When set to 1, use expensive methods to eliminate all redundant constraints",
567 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIGNMENT_CHECKS,
568 "vect-max-version-for-alignment-checks",
569 "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alignment check
",
572 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS,
573 "vect
-max
-version
-for
-alias
-checks
",
574 "Bound on number of runtime checks inserted by the vectorizer
's loop versioning for alias check",
577 DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS,
578 "max-cselib-memory-locations",
579 "The maximum memory locations recorded by cselib",
582 #ifdef ENABLE_GC_ALWAYS_COLLECT
583 # define GGC_MIN_EXPAND_DEFAULT 0
584 # define GGC_MIN_HEAPSIZE_DEFAULT 0
586 # define GGC_MIN_EXPAND_DEFAULT 30
587 # define GGC_MIN_HEAPSIZE_DEFAULT 4096
590 DEFPARAM(GGC_MIN_EXPAND,
592 "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap",
593 GGC_MIN_EXPAND_DEFAULT, 0, 0)
595 DEFPARAM(GGC_MIN_HEAPSIZE,
597 "Minimum heap size before we start collecting garbage, in kilobytes",
598 GGC_MIN_HEAPSIZE_DEFAULT, 0, 0)
600 #undef GGC_MIN_EXPAND_DEFAULT
601 #undef GGC_MIN_HEAPSIZE_DEFAULT
603 DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
604 "max-reload-search-insns",
605 "The maximum number of instructions to search backward when looking for equivalent reload",
608 DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS,
609 "max-sched-region-blocks",
610 "The maximum number of blocks in a region to be considered for interblock scheduling",
613 DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS,
614 "max-sched-region-insns",
615 "The maximum number of insns in a region to be considered for interblock scheduling",
618 DEFPARAM(PARAM_MAX_PIPELINE_REGION_BLOCKS,
619 "max-pipeline-region-blocks",
620 "The maximum number of blocks in a region to be considered for interblock scheduling",
623 DEFPARAM(PARAM_MAX_PIPELINE_REGION_INSNS,
624 "max-pipeline-region-insns",
625 "The maximum number of insns in a region to be considered for interblock scheduling",
628 DEFPARAM(PARAM_MIN_SPEC_PROB,
630 "The minimum probability of reaching a source block for interblock speculative scheduling",
633 DEFPARAM(PARAM_MAX_SCHED_EXTEND_REGIONS_ITERS,
634 "max-sched-extend-regions-iters",
635 "The maximum number of iterations through CFG to extend regions",
638 DEFPARAM(PARAM_MAX_SCHED_INSN_CONFLICT_DELAY,
639 "max-sched-insn-conflict-delay",
640 "The maximum conflict delay for an insn to be considered for speculative motion",
643 DEFPARAM(PARAM_SCHED_SPEC_PROB_CUTOFF,
644 "sched-spec-prob-cutoff",
645 "The minimal probability of speculation success (in percents), so that speculative insn will be scheduled.",
648 DEFPARAM(PARAM_SELSCHED_MAX_LOOKAHEAD,
649 "selsched-max-lookahead",
650 "The maximum size of the lookahead window of selective scheduling",
653 DEFPARAM(PARAM_SELSCHED_MAX_SCHED_TIMES,
654 "selsched-max-sched-times",
655 "Maximum number of times that an insn could be scheduled",
658 DEFPARAM(PARAM_SELSCHED_INSNS_TO_RENAME,
659 "selsched-insns-to-rename",
660 "Maximum number of instructions in the ready list that are considered eligible for renaming",
663 DEFPARAM (PARAM_SCHED_MEM_TRUE_DEP_COST,
664 "sched-mem-true-dep-cost",
665 "Minimal distance between possibly conflicting store and load",
668 DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
669 "max-last-value-rtl",
670 "The maximum number of RTL nodes that can be recorded as combiner's last value
",
673 /* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
674 {signed,unsigned} integral types. This determines N.
675 Experimentation shows 256 to be a good value. */
676 DEFPARAM (PARAM_INTEGER_SHARE_LIMIT,
677 "integer
-share
-limit
",
678 "The upper bound for sharing integer constants
",
681 /* Incremental SSA updates for virtual operands may be very slow if
682 there is a large number of mappings to process. In those cases, it
683 is faster to rewrite the virtual symbols from scratch as if they
684 had been recently introduced. This heuristic cannot be applied to
685 SSA mappings for real SSA names, only symbols kept in FUD chains.
687 PARAM_MIN_VIRTUAL_MAPPINGS specifies the minimum number of virtual
688 mappings that should be registered to trigger the heuristic.
690 PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO specifies the ratio between
691 mappings and symbols. If the number of virtual mappings is
692 PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO bigger than the number of
693 virtual symbols to be updated, then the updater switches to a full
694 update for those symbols. */
695 DEFPARAM (PARAM_MIN_VIRTUAL_MAPPINGS,
696 "min
-virtual
-mappings
",
697 "Minimum number of virtual mappings to consider switching to full virtual renames
",
700 DEFPARAM (PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO,
701 "virtual
-mappings
-ratio
",
702 "Ratio between virtual mappings and virtual symbols to do full virtual renames
",
705 DEFPARAM (PARAM_SSP_BUFFER_SIZE,
707 "The lower bound for a buffer to be considered for stack smashing protection
",
710 /* When we thread through a block we have to make copies of the
711 statements within the block. Clearly for large blocks the code
714 PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number
715 of statements and PHI nodes allowed in a block which is going to
716 be duplicated for thread jumping purposes.
718 Some simple analysis showed that more than 99% of the jump
719 threading opportunities are for blocks with less than 15
720 statements. So we can get the benefits of jump threading
721 without excessive code bloat for pathological cases with the
722 throttle set at 15 statements. */
723 DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS,
724 "max
-jump
-thread
-duplication
-stmts
",
725 "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps
",
728 /* This is the maximum number of fields a variable may have before the pointer analysis machinery
729 will stop trying to treat it in a field-sensitive manner.
730 There are programs out there with thousands of fields per structure, and handling them
731 field-sensitively is not worth the cost. */
732 DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE,
733 "max
-fields
-for
-field
-sensitive
",
734 "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable
",
737 DEFPARAM(PARAM_MAX_SCHED_READY_INSNS,
738 "max
-sched
-ready
-insns
",
739 "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass
",
742 /* This is the maximum number of active local stores RTL DSE will consider. */
743 DEFPARAM (PARAM_MAX_DSE_ACTIVE_LOCAL_STORES,
744 "max
-dse
-active
-local
-stores
",
745 "Maximum number of active local stores in RTL dead store elimination
",
748 /* Prefetching and cache-optimizations related parameters. Default values are
749 usually set by machine description. */
751 /* The number of insns executed before prefetch is completed. */
753 DEFPARAM (PARAM_PREFETCH_LATENCY,
755 "The number of insns executed before prefetch is completed
",
758 /* The number of prefetches that can run at the same time. */
760 DEFPARAM (PARAM_SIMULTANEOUS_PREFETCHES,
761 "simultaneous
-prefetches
",
762 "The number of prefetches that can run at the same time
",
765 /* The size of L1 cache in kB. */
767 DEFPARAM (PARAM_L1_CACHE_SIZE,
769 "The size of L1 cache
",
772 /* The size of L1 cache line in bytes. */
774 DEFPARAM (PARAM_L1_CACHE_LINE_SIZE,
775 "l1
-cache
-line
-size
",
776 "The size of L1 cache line
",
779 /* The size of L2 cache in kB. */
781 DEFPARAM (PARAM_L2_CACHE_SIZE,
783 "The size of L2 cache
",
786 /* Whether we should use canonical types rather than deep "structural
"
787 type checking. Setting this value to 1 (the default) improves
788 compilation performance in the C++ and Objective-C++ front end;
789 this value should only be set to zero to work around bugs in the
790 canonical type system by disabling it. */
792 DEFPARAM (PARAM_USE_CANONICAL_TYPES,
793 "use
-canonical
-types
",
794 "Whether to use canonical types
",
797 DEFPARAM (PARAM_MAX_PARTIAL_ANTIC_LENGTH,
798 "max
-partial
-antic
-length
",
799 "Maximum length of partial antic set when performing tree pre optimization
",
802 /* The following is used as a stop-gap limit for cases where really huge
803 SCCs blow up memory and compile-time use too much. If we hit this limit,
804 SCCVN and such FRE and PRE will be not done at all for the current
807 DEFPARAM (PARAM_SCCVN_MAX_SCC_SIZE,
808 "sccvn
-max
-scc
-size
",
809 "Maximum size of a SCC before SCCVN stops processing a function
",
812 DEFPARAM (PARAM_IRA_MAX_LOOPS_NUM,
814 "Max loops number for regional RA
",
817 DEFPARAM (PARAM_IRA_MAX_CONFLICT_TABLE_SIZE,
818 "ira
-max
-conflict
-table
-size
",
819 "Max size of conflict table in MB
",
822 DEFPARAM (PARAM_IRA_LOOP_RESERVED_REGS,
823 "ira
-loop
-reserved
-regs
",
824 "The number of registers in each class kept unused by loop invariant motion
",
827 /* Switch initialization conversion will refuse to create arrays that are
828 bigger than this parameter times the number of switch branches. */
830 DEFPARAM (PARAM_SWITCH_CONVERSION_BRANCH_RATIO,
831 "switch
-conversion
-max
-branch
-ratio
",
832 "The maximum ratio between array size and switch branches for
"
833 "a switch conversion to take place
",
836 /* Size of tiles when doing loop blocking. */
838 DEFPARAM (PARAM_LOOP_BLOCK_TILE_SIZE,
839 "loop
-block
-tile
-size
",
840 "size of tiles for loop blocking
",
843 /* Maximal number of parameters that we allow in a SCoP. */
845 DEFPARAM (PARAM_GRAPHITE_MAX_NB_SCOP_PARAMS,
846 "graphite
-max
-nb
-scop
-params
",
847 "maximum number of parameters in a SCoP
",
850 /* Maximal number of basic blocks in the functions analyzed by Graphite. */
852 DEFPARAM (PARAM_GRAPHITE_MAX_BBS_PER_FUNCTION,
853 "graphite
-max
-bbs
-per
-function
",
854 "maximum number of basic blocks per function to be analyzed by Graphite
",
857 /* Avoid doing loop invariant motion on very large loops. */
859 DEFPARAM (PARAM_LOOP_INVARIANT_MAX_BBS_IN_LOOP,
860 "loop
-invariant
-max
-bbs
-in
-loop
",
861 "Max basic blocks number in loop for loop invariant motion
",
864 /* Promote indirect call to conditional direct call only
865 when the percentage of the target count over the total
866 indirect call count is no smaller than the threshold. */
867 DEFPARAM (PARAM_ICALL_PROMOTE_PERCENT_THRESHOLD,
868 "icall
-promote
-target
-percent
-threshold
",
869 "percentage threshold for direct call promotion
"
870 " of a callee target
",
873 DEFPARAM (PARAM_ICALL_PROMOTE_COUNT_THRESHOLD,
874 "icall
-promote
-target_count
-threshold
",
875 "call count threshold for direct call promotion
"
876 " of a callee target
",
879 /* 0: do not always inline icall target:
880 other value: always inline icall target when call count
883 DEFPARAM (PARAM_ALWAYS_INLINE_ICALL_TARGET,
884 "always
-inline
-icall
-target
",
885 "force inline indirect call target when promoted
",
888 /* Force the compiler to be in LIPO mode even there is no
889 profile data available. -fripa is also needed. */
890 DEFPARAM (PARAM_FORCE_LIPO_MODE,
892 "force LIPO compilation mode
",
895 /* Limit max module group size in LIPO mode. When the value
896 is set to 0 (which is the default), there is no limit. */
897 DEFPARAM (PARAM_MAX_LIPO_GROUP,
899 "maximum module group size.
",
902 /* In LIPO mode, stop processing any further auxiliary modules
903 if current memory consumption exceeds this limit (in kb). */
904 DEFPARAM (PARAM_MAX_LIPO_MEMORY,
906 "don
't import aux files if memory consumption exceeds this value",
909 DEFPARAM (PARAM_PROFILE_GENERATE_SAMPLING_RATE,
910 "profile-generate-sampling-rate",
911 "sampling rate with -fprofile-generate-sampling",
914 /* Used for debugging purpose. Tell the compiler to find
915 the gcda file in the current directory. */
916 DEFPARAM (PARAM_GCOV_DEBUG,
918 "Looking for gcda file in current dir.",
921 DEFPARAM (PARAM_REUSEDIST_MEAN_DIST_LARGE_THRESH,
922 "reusedist-mean-dist-large-thresh",
923 "Generate NTA stringops only if reusedist at least this size",
926 DEFPARAM (PARAM_REUSEDIST_MEAN_DIST_SMALL_THRESH,
927 "reusedist-mean-dist-small-thresh",
928 "Force temporal stringops if reusedist at most this size",
931 DEFPARAM (PARAM_REUSEDIST_CALL_COUNT_THRESH,
932 "reusedist-call-count-thresh",
933 "Generate NTA stringops only if call count at least this large",
936 DEFPARAM (PARAM_REUSEDIST_MEMCPY_SIZE_THRESH,
937 "reusedist-memcpy-size-thresh",
938 "Generate memcpy-nta only if size at least this large",
941 DEFPARAM (PARAM_REUSEDIST_MEMSET_SIZE_THRESH,
942 "reusedist-memset-size-thresh",
943 "Generate NTA memset only if size at least this large",
946 /* Avoid SLP vectorization of large basic blocks. */
947 DEFPARAM (PARAM_SLP_MAX_INSNS_IN_BB,
948 "slp-max-insns-in-bb",
949 "Maximum number of instructions in basic block to be considered for SLP vectorization",
952 DEFPARAM (PARAM_MIN_INSN_TO_PREFETCH_RATIO,
953 "min-insn-to-prefetch-ratio",
954 "Min. ratio of insns to prefetches to enable prefetching for "
955 "a loop with an unknown trip count",
958 DEFPARAM (PARAM_PREFETCH_MIN_INSN_TO_MEM_RATIO,
959 "prefetch-min-insn-to-mem-ratio",
960 "Min. ratio of insns to mem ops to enable prefetching in a loop",
963 /* Set maximum hash table size for var tracking. */
965 DEFPARAM (PARAM_MAX_VARTRACK_SIZE,
967 "Max. size of var tracking hash tables",
970 /* Set minimum insn uid for non-debug insns. */
972 DEFPARAM (PARAM_MIN_NONDEBUG_INSN_UID,
973 "min-nondebug-insn-uid",
974 "The minimum UID to be used for a nondebug insn",
977 DEFPARAM (PARAM_IPA_SRA_PTR_GROWTH_FACTOR,
978 "ipa-sra-ptr-growth-factor",
979 "Maximum allowed growth of size of new parameters ipa-sra replaces "
980 "a pointer to an aggregate with",
983 DEFPARAM (PARAM_DEVIRT_TYPE_LIST_SIZE,
984 "devirt-type-list-size",
985 "Maximum size of a type list associated with each parameter for "
989 /* WHOPR partitioning configuration. */
991 DEFPARAM (PARAM_LTO_PARTITIONS,
993 "Number of paritions program should be split to",
996 DEFPARAM (MIN_PARTITION_SIZE,
998 "Size of minimal paritition for WHOPR (in estimated instructions)",
1001 DEFPARAM (PARAM_MIN_MCF_CANCEL_ITERS,
1002 "min-mcf-cancel-iters",
1003 "the minimum number of iterations of negative cycle cancellation "
1007 /* Diagnostic parameters. */
1009 DEFPARAM (CXX_MAX_NAMESPACES_FOR_DIAGNOSTIC_HELP,
1010 "cxx-max-namespaces-for-diagnostic-help",
1011 "Maximum number of namespaces to search for alternatives when "
1012 "name lookup fails",
1015 DEFPARAM (PARAM_NUMBER_OF_MVERSN_CLONES,
1016 "num-mversn-clones",
1017 "maximum number of functions to be cloned while doing "
1021 DEFPARAM (PARAM_MVERSN_CLONE_CGRAPH_DEPTH,
1022 "mversn-clone-depth",
1023 "maximum length of the call graph path to be cloned "
1024 "while doing multiversioning",
1027 /* Only output those call graph edges in .gnu.callgraph.text sections
1028 whose count is greater than this value. */
1029 DEFPARAM (PARAM_NOTE_CGRAPH_SECTION_EDGE_THRESHOLD,
1030 "note-cgraph-section-edge-threshold",
1031 "minimum call graph edge count for inclusion in "
1032 ".gnu.callgraph.text section",
1035 DEFPARAM (PARAM_PMU_PROFILE_N_ADDRESS,
1036 "pmu_profile_n_addresses",
1037 "While doing PMU profiling symbolize this many top addresses.",
1040 DEFPARAM (PARAM_MAX_FUNCTION_SIZE_FOR_AUTO_CLONING,
1041 "autoclone-function-size-limit",
1042 "Do not auto clone functions beyond this size.",
1045 /* Parameters to be used with -mpatch-functions-for-instrumentation.
1046 See config/i386/i386.opt */
1047 DEFPARAM (PARAM_FUNCTION_PATCH_MIN_INSTRUCTIONS,
1048 "function-patch-min-instructions",
1049 "Minimum number of instructions in the function without loop before "
1050 "the function is qualified for patching for instrumentation (for use "
1051 "with -mpatch-functions-for-instrumentation)",