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 /* Limit of iterations of early inliner. This basically bounds number of
114 nested indirect calls early inliner can resolve. Deeper chains are still
115 handled by late inlining. */
116 DEFPARAM (PARAM_EARLY_INLINER_MAX_ITERATIONS,
117 "max-early-inliner-iterations",
118 "The maximum number of nested indirect inlining performed by early inliner",
121 /* Limit on probability of entry BB. */
122 DEFPARAM (PARAM_COMDAT_SHARING_PROBABILITY,
123 "comdat-sharing-probability",
124 "Probability that COMDAT function will be shared with different compilatoin unit",
127 /* Limit on probability of entry BB. */
128 DEFPARAM (PARAM_PARTIAL_INLINING_ENTRY_PROBABILITY,
129 "partial-inlining-entry-probability",
130 "Maximum probability of the entry BB of split region (in percent relative to entry BB of the function) to make partial inlining happen",
133 /* Limit the number of expansions created by the variable expansion
134 optimization to avoid register pressure. */
135 DEFPARAM (PARAM_MAX_VARIABLE_EXPANSIONS,
136 "max-variable-expansions-in-unroller",
137 "If -fvariable-expansion-in-unroller is used, the maximum number of times that an individual variable will be expanded during loop unrolling",
140 /* Limit loop autovectorization to loops with large enough iteration count. */
141 DEFPARAM (PARAM_MIN_VECT_LOOP_BOUND,
142 "min-vect-loop-bound",
143 "If -ftree-vectorize is used, the minimal loop bound of a loop to be considered for vectorization",
146 /* The maximum number of instructions to consider when looking for an
147 instruction to fill a delay slot. If more than this arbitrary
148 number of instructions is searched, the time savings from filling
149 the delay slot will be minimal so stop searching. Increasing
150 values mean more aggressive optimization, making the compile time
151 increase with probably small improvement in executable run time. */
152 DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH,
153 "max-delay-slot-insn-search",
154 "The maximum number of instructions to consider to fill a delay slot",
157 /* When trying to fill delay slots, the maximum number of instructions
158 to consider when searching for a block with valid live register
159 information. Increasing this arbitrarily chosen value means more
160 aggressive optimization, increasing the compile time. This
161 parameter should be removed when the delay slot code is rewritten
162 to maintain the control-flow graph. */
163 DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH,
164 "max-delay-slot-live-search",
165 "The maximum number of instructions to consider to find accurate live register information",
168 /* This parameter limits the number of branch elements that the
169 scheduler will track anti-dependencies through without resetting
170 the tracking mechanism. Large functions with few calls or barriers
171 can generate lists containing many 1000's of dependencies. Generally
172 the compiler either uses all available memory
, or runs for far too long.
*/
173 DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH
,
174 "max-pending-list-length",
175 "The maximum length of scheduling's pending operations list",
178 DEFPARAM(PARAM_LARGE_FUNCTION_INSNS
,
179 "large-function-insns",
180 "The size of function body to be considered large",
182 DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH
,
183 "large-function-growth",
184 "Maximal growth due to inlining of large function (in percent)",
186 DEFPARAM(PARAM_LARGE_UNIT_INSNS
,
188 "The size of translation unit to be considered large",
190 DEFPARAM(PARAM_INLINE_UNIT_GROWTH
,
191 "inline-unit-growth",
192 "How much can given compilation unit grow because of the inlining (in percent)",
194 DEFPARAM(PARAM_IPCP_UNIT_GROWTH
,
196 "How much can given compilation unit grow because of the interprocedural constant propagation (in percent)",
198 DEFPARAM(PARAM_EARLY_INLINING_INSNS
,
199 "early-inlining-insns",
200 "Maximal estimated growth of function body caused by early inlining of single call",
202 DEFPARAM(PARAM_LARGE_STACK_FRAME
,
204 "The size of stack frame to be considered large",
206 DEFPARAM(PARAM_STACK_FRAME_GROWTH
,
207 "large-stack-frame-growth",
208 "Maximal stack frame growth due to inlining (in percent)",
211 /* The GCSE optimization will be disabled if it would require
212 significantly more memory than this value.
*/
213 DEFPARAM(PARAM_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",
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",
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",
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",
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",
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
260 DEFPARAM(PARAM_MAX_HOIST_DEPTH,
262 "Maximum depth of search in the dominator tree for expressions to hoist",
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
272 DEFPARAM(PARAM_MAX_UNROLLED_INSNS,
273 "max-unrolled-insns",
274 "The maximum number of instructions to consider to unroll in a loop",
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",
282 /* The maximum number of unrollings of a single loop. */
283 DEFPARAM(PARAM_MAX_UNROLL_TIMES,
285 "The maximum number of unrollings of a single loop",
287 /* The maximum number of insns of a peeled loop. */
288 DEFPARAM(PARAM_MAX_PEELED_INSNS,
290 "The maximum number of insns of a peeled loop",
292 /* The maximum number of peelings of a single loop. */
293 DEFPARAM(PARAM_MAX_PEEL_TIMES,
295 "The maximum number of peelings of a single loop",
297 /* The maximum number of insns of a peeled loop. */
298 DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS,
299 "max-completely-peeled-insns",
300 "The maximum number of insns of a completely peeled loop",
302 /* The maximum number of peelings of a single loop that is peeled completely. */
303 DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES,
304 "max-completely-peel-times",
305 "The maximum number of peelings of a single loop that is peeled completely",
307 /* The maximum number of insns of a peeled loop that rolls only once. */
308 DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS,
309 "max-once-peeled-insns",
310 "The maximum number of insns of a peeled loop that rolls only once",
312 /* The maximum depth of a loop nest we completely peel. */
313 DEFPARAM(PARAM_MAX_UNROLL_ITERATIONS,
314 "max-completely-peel-loop-nest-depth",
315 "The maximum depth of a loop nest we completely peel",
318 /* The maximum number of insns of an unswitched loop. */
319 DEFPARAM(PARAM_MAX_UNSWITCH_INSNS,
320 "max-unswitch-insns",
321 "The maximum number of insns of an unswitched loop",
323 /* The maximum level of recursion in unswitch_single_loop. */
324 DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL,
325 "max-unswitch-level",
326 "The maximum number of unswitchings in a single loop",
329 /* The maximum number of iterations of a loop the brute force algorithm
330 for analysis of # of iterations of the loop tries to evaluate. */
331 DEFPARAM(PARAM_MAX_ITERATIONS_TO_TRACK,
332 "max-iterations-to-track",
333 "Bound on the number of iterations the brute force # of iterations analysis algorithm evaluates",
335 /* A cutoff to avoid costly computations of the number of iterations in
336 the doloop transformation. */
337 DEFPARAM(PARAM_MAX_ITERATIONS_COMPUTATION_COST,
338 "max-iterations-computation-cost",
339 "Bound on the cost of an expression to compute the number of iterations",
342 /* This parameter is used to tune SMS MAX II calculations. */
343 DEFPARAM(PARAM_SMS_MAX_II_FACTOR,
345 "A factor for tuning the upper bound that swing modulo scheduler uses for scheduling a loop",
347 DEFPARAM(PARAM_SMS_DFA_HISTORY,
349 "The number of cycles the swing modulo scheduler considers when checking conflicts using DFA",
351 DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD,
352 "sms-loop-average-count-threshold",
353 "A threshold on the average loop count considered by the swing modulo scheduler",
356 DEFPARAM(HOT_BB_COUNT_FRACTION,
357 "hot-bb-count-fraction",
358 "Select fraction of the maximal count of repetitions of basic block in program given basic block needs to have to be considered hot",
360 DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
361 "hot-bb-frequency-fraction",
362 "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot",
365 DEFPARAM (PARAM_ALIGN_THRESHOLD,
367 "Select fraction of the maximal frequency of executions of basic block in function given basic block get alignment",
370 DEFPARAM (PARAM_ALIGN_LOOP_ITERATIONS,
371 "align-loop-iterations",
372 "Loops iterating at least selected number of iterations will get loop alignement.",
375 /* For guessed profiles, the loops having unknown number of iterations
376 are predicted to iterate relatively few (10) times at average.
377 For functions containing one loop with large known number of iterations
378 and other loops having unbounded loops we would end up predicting all
379 the other loops cold that is not usually the case. So we need to artificially
382 We need to cut the maximal predicted iterations to large enough iterations
383 so the loop appears important, but safely within HOT_BB_COUNT_FRACTION
386 DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS,
387 "max-predicted-iterations",
388 "The maximum number of loop iterations we predict statically",
390 DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
391 "tracer-dynamic-coverage-feedback",
392 "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available",
394 DEFPARAM(TRACER_DYNAMIC_COVERAGE,
395 "tracer-dynamic-coverage",
396 "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available",
398 DEFPARAM(TRACER_MAX_CODE_GROWTH,
399 "tracer-max-code-growth",
400 "Maximal code growth caused by tail duplication (in percent)",
402 DEFPARAM(TRACER_MIN_BRANCH_RATIO,
403 "tracer-min-branch-ratio",
404 "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent)",
406 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
407 "tracer-min-branch-probability-feedback",
408 "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available",
410 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
411 "tracer-min-branch-probability",
412 "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available",
415 /* The maximum number of incoming edges to consider for crossjumping. */
416 DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
417 "max-crossjump-edges",
418 "The maximum number of incoming edges to consider for crossjumping",
421 /* The minimum number of matching instructions to consider for crossjumping. */
422 DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS,
423 "min-crossjump-insns",
424 "The minimum number of matching instructions to consider for crossjumping",
427 /* The maximum number expansion factor when copying basic blocks. */
428 DEFPARAM(PARAM_MAX_GROW_COPY_BB_INSNS,
429 "max-grow-copy-bb-insns",
430 "The maximum expansion factor when copying basic blocks",
433 /* The maximum number of insns to duplicate when unfactoring computed gotos. */
434 DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS,
435 "max-goto-duplication-insns",
436 "The maximum number of insns to duplicate when unfactoring computed gotos",
439 /* The maximum length of path considered in cse. */
440 DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
441 "max-cse-path-length",
442 "The maximum length of path considered in cse",
444 DEFPARAM(PARAM_MAX_CSE_INSNS,
446 "The maximum instructions CSE process before flushing",
449 /* The cost of expression in loop invariant motion that is considered
451 DEFPARAM(PARAM_LIM_EXPENSIVE,
453 "The minimum cost of an expensive expression in the loop invariant motion",
456 /* Bound on number of candidates for induction variables below that
457 all candidates are considered for each use in induction variable
460 DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND,
461 "iv-consider-all-candidates-bound",
462 "Bound on number of candidates below that all candidates are considered in iv optimizations",
465 /* The induction variable optimizations give up on loops that contain more
466 induction variable uses. */
468 DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES,
469 "iv-max-considered-uses",
470 "Bound on number of iv uses in loop optimized in iv optimizations",
473 /* If there are at most this number of ivs in the set, try removing unnecessary
474 ivs from the set always. */
476 DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND,
477 "iv-always-prune-cand-set-bound",
478 "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization",
481 DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE,
482 "scev-max-expr-size",
483 "Bound on size of expressions used in the scalar evolutions analyzer",
486 DEFPARAM(PARAM_SCEV_MAX_EXPR_COMPLEXITY,
487 "scev-max-expr-complexity",
488 "Bound on the complexity of the expressions in the scalar evolutions analyzer",
491 DEFPARAM(PARAM_OMEGA_MAX_VARS,
493 "Bound on the number of variables in Omega constraint systems",
496 DEFPARAM(PARAM_OMEGA_MAX_GEQS,
498 "Bound on the number of inequalities in Omega constraint systems",
501 DEFPARAM(PARAM_OMEGA_MAX_EQS,
503 "Bound on the number of equalities in Omega constraint systems",
506 DEFPARAM(PARAM_OMEGA_MAX_WILD_CARDS,
507 "omega-max-wild-cards",
508 "Bound on the number of wild cards in Omega constraint systems",
511 DEFPARAM(PARAM_OMEGA_HASH_TABLE_SIZE,
512 "omega-hash-table-size",
513 "Bound on the size of the hash table in Omega constraint systems",
516 DEFPARAM(PARAM_OMEGA_MAX_KEYS,
518 "Bound on the number of keys in Omega constraint systems",
521 DEFPARAM(PARAM_OMEGA_ELIMINATE_REDUNDANT_CONSTRAINTS,
522 "omega-eliminate-redundant-constraints",
523 "When set to 1, use expensive methods to eliminate all redundant constraints",
526 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIGNMENT_CHECKS,
527 "vect-max-version-for-alignment-checks",
528 "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alignment check
",
531 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS,
532 "vect
-max
-version
-for
-alias
-checks
",
533 "Bound on number of runtime checks inserted by the vectorizer
's loop versioning for alias check",
536 DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS,
537 "max-cselib-memory-locations",
538 "The maximum memory locations recorded by cselib",
541 #ifdef ENABLE_GC_ALWAYS_COLLECT
542 # define GGC_MIN_EXPAND_DEFAULT 0
543 # define GGC_MIN_HEAPSIZE_DEFAULT 0
545 # define GGC_MIN_EXPAND_DEFAULT 30
546 # define GGC_MIN_HEAPSIZE_DEFAULT 4096
549 DEFPARAM(GGC_MIN_EXPAND,
551 "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap",
552 GGC_MIN_EXPAND_DEFAULT, 0, 0)
554 DEFPARAM(GGC_MIN_HEAPSIZE,
556 "Minimum heap size before we start collecting garbage, in kilobytes",
557 GGC_MIN_HEAPSIZE_DEFAULT, 0, 0)
559 #undef GGC_MIN_EXPAND_DEFAULT
560 #undef GGC_MIN_HEAPSIZE_DEFAULT
562 DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
563 "max-reload-search-insns",
564 "The maximum number of instructions to search backward when looking for equivalent reload",
567 DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS,
568 "max-sched-region-blocks",
569 "The maximum number of blocks in a region to be considered for interblock scheduling",
572 DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS,
573 "max-sched-region-insns",
574 "The maximum number of insns in a region to be considered for interblock scheduling",
577 DEFPARAM(PARAM_MAX_PIPELINE_REGION_BLOCKS,
578 "max-pipeline-region-blocks",
579 "The maximum number of blocks in a region to be considered for interblock scheduling",
582 DEFPARAM(PARAM_MAX_PIPELINE_REGION_INSNS,
583 "max-pipeline-region-insns",
584 "The maximum number of insns in a region to be considered for interblock scheduling",
587 DEFPARAM(PARAM_MIN_SPEC_PROB,
589 "The minimum probability of reaching a source block for interblock speculative scheduling",
592 DEFPARAM(PARAM_MAX_SCHED_EXTEND_REGIONS_ITERS,
593 "max-sched-extend-regions-iters",
594 "The maximum number of iterations through CFG to extend regions",
597 DEFPARAM(PARAM_MAX_SCHED_INSN_CONFLICT_DELAY,
598 "max-sched-insn-conflict-delay",
599 "The maximum conflict delay for an insn to be considered for speculative motion",
602 DEFPARAM(PARAM_SCHED_SPEC_PROB_CUTOFF,
603 "sched-spec-prob-cutoff",
604 "The minimal probability of speculation success (in percents), so that speculative insn will be scheduled.",
607 DEFPARAM(PARAM_SELSCHED_MAX_LOOKAHEAD,
608 "selsched-max-lookahead",
609 "The maximum size of the lookahead window of selective scheduling",
612 DEFPARAM(PARAM_SELSCHED_MAX_SCHED_TIMES,
613 "selsched-max-sched-times",
614 "Maximum number of times that an insn could be scheduled",
617 DEFPARAM(PARAM_SELSCHED_INSNS_TO_RENAME,
618 "selsched-insns-to-rename",
619 "Maximum number of instructions in the ready list that are considered eligible for renaming",
622 DEFPARAM (PARAM_SCHED_MEM_TRUE_DEP_COST,
623 "sched-mem-true-dep-cost",
624 "Minimal distance between possibly conflicting store and load",
627 DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
628 "max-last-value-rtl",
629 "The maximum number of RTL nodes that can be recorded as combiner's last value
",
632 /* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
633 {signed,unsigned} integral types. This determines N.
634 Experimentation shows 256 to be a good value. */
635 DEFPARAM (PARAM_INTEGER_SHARE_LIMIT,
636 "integer
-share
-limit
",
637 "The upper bound for sharing integer constants
",
640 /* Incremental SSA updates for virtual operands may be very slow if
641 there is a large number of mappings to process. In those cases, it
642 is faster to rewrite the virtual symbols from scratch as if they
643 had been recently introduced. This heuristic cannot be applied to
644 SSA mappings for real SSA names, only symbols kept in FUD chains.
646 PARAM_MIN_VIRTUAL_MAPPINGS specifies the minimum number of virtual
647 mappings that should be registered to trigger the heuristic.
649 PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO specifies the ratio between
650 mappings and symbols. If the number of virtual mappings is
651 PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO bigger than the number of
652 virtual symbols to be updated, then the updater switches to a full
653 update for those symbols. */
654 DEFPARAM (PARAM_MIN_VIRTUAL_MAPPINGS,
655 "min
-virtual
-mappings
",
656 "Minimum number of virtual mappings to consider switching to full virtual renames
",
659 DEFPARAM (PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO,
660 "virtual
-mappings
-ratio
",
661 "Ratio between virtual mappings and virtual symbols to do full virtual renames
",
664 DEFPARAM (PARAM_SSP_BUFFER_SIZE,
666 "The lower bound for a buffer to be considered for stack smashing protection
",
669 /* When we thread through a block we have to make copies of the
670 statements within the block. Clearly for large blocks the code
673 PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number
674 of statements and PHI nodes allowed in a block which is going to
675 be duplicated for thread jumping purposes.
677 Some simple analysis showed that more than 99% of the jump
678 threading opportunities are for blocks with less than 15
679 statements. So we can get the benefits of jump threading
680 without excessive code bloat for pathological cases with the
681 throttle set at 15 statements. */
682 DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS,
683 "max
-jump
-thread
-duplication
-stmts
",
684 "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps
",
687 /* This is the maximum number of fields a variable may have before the pointer analysis machinery
688 will stop trying to treat it in a field-sensitive manner.
689 There are programs out there with thousands of fields per structure, and handling them
690 field-sensitively is not worth the cost. */
691 DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE,
692 "max
-fields
-for
-field
-sensitive
",
693 "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable
",
696 DEFPARAM(PARAM_MAX_SCHED_READY_INSNS,
697 "max
-sched
-ready
-insns
",
698 "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass
",
701 /* This is the maximum number of active local stores RTL DSE will consider. */
702 DEFPARAM (PARAM_MAX_DSE_ACTIVE_LOCAL_STORES,
703 "max
-dse
-active
-local
-stores
",
704 "Maximum number of active local stores in RTL dead store elimination
",
707 /* Prefetching and cache-optimizations related parameters. Default values are
708 usually set by machine description. */
710 /* The number of insns executed before prefetch is completed. */
712 DEFPARAM (PARAM_PREFETCH_LATENCY,
714 "The number of insns executed before prefetch is completed
",
717 /* The number of prefetches that can run at the same time. */
719 DEFPARAM (PARAM_SIMULTANEOUS_PREFETCHES,
720 "simultaneous
-prefetches
",
721 "The number of prefetches that can run at the same time
",
724 /* The size of L1 cache in kB. */
726 DEFPARAM (PARAM_L1_CACHE_SIZE,
728 "The size of L1 cache
",
731 /* The size of L1 cache line in bytes. */
733 DEFPARAM (PARAM_L1_CACHE_LINE_SIZE,
734 "l1
-cache
-line
-size
",
735 "The size of L1 cache line
",
738 /* The size of L2 cache in kB. */
740 DEFPARAM (PARAM_L2_CACHE_SIZE,
742 "The size of L2 cache
",
745 /* Whether we should use canonical types rather than deep "structural
"
746 type checking. Setting this value to 1 (the default) improves
747 compilation performance in the C++ and Objective-C++ front end;
748 this value should only be set to zero to work around bugs in the
749 canonical type system by disabling it. */
751 DEFPARAM (PARAM_USE_CANONICAL_TYPES,
752 "use
-canonical
-types
",
753 "Whether to use canonical types
",
756 DEFPARAM (PARAM_MAX_PARTIAL_ANTIC_LENGTH,
757 "max
-partial
-antic
-length
",
758 "Maximum length of partial antic set when performing tree pre optimization
",
761 /* The following is used as a stop-gap limit for cases where really huge
762 SCCs blow up memory and compile-time use too much. If we hit this limit,
763 SCCVN and such FRE and PRE will be not done at all for the current
766 DEFPARAM (PARAM_SCCVN_MAX_SCC_SIZE,
767 "sccvn
-max
-scc
-size
",
768 "Maximum size of a SCC before SCCVN stops processing a function
",
771 DEFPARAM (PARAM_IRA_MAX_LOOPS_NUM,
773 "Max loops number for regional RA
",
776 DEFPARAM (PARAM_IRA_MAX_CONFLICT_TABLE_SIZE,
777 "ira
-max
-conflict
-table
-size
",
778 "Max size of conflict table in MB
",
781 DEFPARAM (PARAM_IRA_LOOP_RESERVED_REGS,
782 "ira
-loop
-reserved
-regs
",
783 "The number of registers in each class kept unused by loop invariant motion
",
786 /* Switch initialization conversion will refuse to create arrays that are
787 bigger than this parameter times the number of switch branches. */
789 DEFPARAM (PARAM_SWITCH_CONVERSION_BRANCH_RATIO,
790 "switch
-conversion
-max
-branch
-ratio
",
791 "The maximum ratio between array size and switch branches for
"
792 "a switch conversion to take place
",
795 /* Size of tiles when doing loop blocking. */
797 DEFPARAM (PARAM_LOOP_BLOCK_TILE_SIZE,
798 "loop
-block
-tile
-size
",
799 "size of tiles for loop blocking
",
802 /* Maximal number of parameters that we allow in a SCoP. */
804 DEFPARAM (PARAM_GRAPHITE_MAX_NB_SCOP_PARAMS,
805 "graphite
-max
-nb
-scop
-params
",
806 "maximum number of parameters in a SCoP
",
809 /* Maximal number of basic blocks in the functions analyzed by Graphite. */
811 DEFPARAM (PARAM_GRAPHITE_MAX_BBS_PER_FUNCTION,
812 "graphite
-max
-bbs
-per
-function
",
813 "maximum number of basic blocks per function to be analyzed by Graphite
",
816 /* Avoid doing loop invariant motion on very large loops. */
818 DEFPARAM (PARAM_LOOP_INVARIANT_MAX_BBS_IN_LOOP,
819 "loop
-invariant
-max
-bbs
-in
-loop
",
820 "Max basic blocks number in loop for loop invariant motion
",
823 /* Avoid SLP vectorization of large basic blocks. */
824 DEFPARAM (PARAM_SLP_MAX_INSNS_IN_BB,
825 "slp
-max
-insns
-in
-bb
",
826 "Maximum number of instructions in basic block to be considered for SLP vectorization
",
829 DEFPARAM (PARAM_MIN_INSN_TO_PREFETCH_RATIO,
830 "min
-insn
-to
-prefetch
-ratio
",
831 "Min. ratio of insns to prefetches to enable prefetching for
"
832 "a loop with an unknown trip count
",
835 DEFPARAM (PARAM_PREFETCH_MIN_INSN_TO_MEM_RATIO,
836 "prefetch
-min
-insn
-to
-mem
-ratio
",
837 "Min. ratio of insns to mem ops to enable prefetching in a loop
",
840 /* Set maximum hash table size for var tracking. */
842 DEFPARAM (PARAM_MAX_VARTRACK_SIZE,
844 "Max. size of var tracking hash tables
",
847 /* Set minimum insn uid for non-debug insns. */
849 DEFPARAM (PARAM_MIN_NONDEBUG_INSN_UID,
850 "min
-nondebug
-insn
-uid
",
851 "The minimum UID to be used for a nondebug insn
",
854 DEFPARAM (PARAM_IPA_SRA_PTR_GROWTH_FACTOR,
855 "ipa
-sra
-ptr
-growth
-factor
",
856 "Maximum allowed growth of size of new parameters ipa
-sra replaces
"
857 "a pointer to an aggregate with
",
860 DEFPARAM (PARAM_DEVIRT_TYPE_LIST_SIZE,
861 "devirt
-type
-list
-size
",
862 "Maximum size of a type list associated with each parameter for
"
866 /* WHOPR partitioning configuration. */
868 DEFPARAM (PARAM_LTO_PARTITIONS,
870 "Number of paritions program should be split to
",
873 DEFPARAM (MIN_PARTITION_SIZE,
875 "Size of minimal paritition for
WHOPR (in estimated instructions
)",
878 /* Diagnostic parameters. */
880 DEFPARAM (CXX_MAX_NAMESPACES_FOR_DIAGNOSTIC_HELP,
881 "cxx
-max
-namespaces
-for
-diagnostic
-help
",
882 "Maximum number of namespaces to search for alternatives when
"