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 /* When branch is predicted to be taken with probability lower than this
43 threshold (in percent), then it is considered well predictable. */
44 DEFPARAM (PARAM_PREDICTABLE_BRANCH_OUTCOME,
45 "predictable-branch-outcome",
46 "Maximal estimated outcome of branch considered predictable",
49 DEFPARAM (PARAM_INLINE_MIN_SPEEDUP,
51 "The minimal estimated speedup allowing inliner to ignore inline-insns-single and inline-isnsns-auto",
54 /* The single function inlining limit. This is the maximum size
55 of a function counted in internal gcc instructions (not in
56 real machine instructions) that is eligible for inlining
58 The default value is 450.
59 Only functions marked inline (or methods defined in the class
60 definition for C++) are affected by this.
61 There are more restrictions to inlining: If inlined functions
62 call other functions, the already inlined instructions are
63 counted and once the recursive inline limit (see
64 "max-inline-insns" parameter) is exceeded, the acceptable size
66 DEFPARAM (PARAM_MAX_INLINE_INSNS_SINGLE,
67 "max-inline-insns-single",
68 "The maximum number of instructions in a single function eligible for inlining",
71 /* The single function inlining limit for functions that are
72 inlined by virtue of -finline-functions (-O3).
73 This limit should be chosen to be below or equal to the limit
74 that is applied to functions marked inlined (or defined in the
75 class declaration in C++) given by the "max-inline-insns-single"
77 The default value is 40. */
78 DEFPARAM (PARAM_MAX_INLINE_INSNS_AUTO,
79 "max-inline-insns-auto",
80 "The maximum number of instructions when automatically inlining",
83 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE,
84 "max-inline-insns-recursive",
85 "The maximum number of instructions inline function can grow to via recursive inlining",
88 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO,
89 "max-inline-insns-recursive-auto",
90 "The maximum number of instructions non-inline function can grow to via recursive inlining",
93 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH,
94 "max-inline-recursive-depth",
95 "The maximum depth of recursive inlining for inline functions",
98 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO,
99 "max-inline-recursive-depth-auto",
100 "The maximum depth of recursive inlining for non-inline functions",
103 DEFPARAM (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY,
104 "min-inline-recursive-probability",
105 "Inline recursively only when the probability of call being executed exceeds the parameter",
108 /* Limit of iterations of early inliner. This basically bounds number of
109 nested indirect calls early inliner can resolve. Deeper chains are still
110 handled by late inlining. */
111 DEFPARAM (PARAM_EARLY_INLINER_MAX_ITERATIONS,
112 "max-early-inliner-iterations",
113 "The maximum number of nested indirect inlining performed by early inliner",
116 /* Limit on probability of entry BB. */
117 DEFPARAM (PARAM_COMDAT_SHARING_PROBABILITY,
118 "comdat-sharing-probability",
119 "Probability that COMDAT function will be shared with different compilation unit",
122 /* Limit on probability of entry BB. */
123 DEFPARAM (PARAM_PARTIAL_INLINING_ENTRY_PROBABILITY,
124 "partial-inlining-entry-probability",
125 "Maximum probability of the entry BB of split region (in percent relative to entry BB of the function) to make partial inlining happen",
128 /* Limit the number of expansions created by the variable expansion
129 optimization to avoid register pressure. */
130 DEFPARAM (PARAM_MAX_VARIABLE_EXPANSIONS,
131 "max-variable-expansions-in-unroller",
132 "If -fvariable-expansion-in-unroller is used, the maximum number of times that an individual variable will be expanded during loop unrolling",
135 /* Limit loop autovectorization to loops with large enough iteration count. */
136 DEFPARAM (PARAM_MIN_VECT_LOOP_BOUND,
137 "min-vect-loop-bound",
138 "If -ftree-vectorize is used, the minimal loop bound of a loop to be considered for vectorization",
141 /* The maximum number of instructions to consider when looking for an
142 instruction to fill a delay slot. If more than this arbitrary
143 number of instructions is searched, the time savings from filling
144 the delay slot will be minimal so stop searching. Increasing
145 values mean more aggressive optimization, making the compile time
146 increase with probably small improvement in executable run time. */
147 DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH,
148 "max-delay-slot-insn-search",
149 "The maximum number of instructions to consider to fill a delay slot",
152 /* When trying to fill delay slots, the maximum number of instructions
153 to consider when searching for a block with valid live register
154 information. Increasing this arbitrarily chosen value means more
155 aggressive optimization, increasing the compile time. This
156 parameter should be removed when the delay slot code is rewritten
157 to maintain the control-flow graph. */
158 DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH,
159 "max-delay-slot-live-search",
160 "The maximum number of instructions to consider to find accurate live register information",
163 /* This parameter limits the number of branch elements that the
164 scheduler will track anti-dependencies through without resetting
165 the tracking mechanism. Large functions with few calls or barriers
166 can generate lists containing many 1000's of dependencies. Generally
167 the compiler either uses all available memory, or runs for far too long. */
168 DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH,
169 "max-pending-list-length",
170 "The maximum length of scheduling's pending operations list",
173 /* This parameter limits the number of backtracking attempts when using the
174 haifa scheduler for modulo scheduling. */
175 DEFPARAM(PARAM_MAX_MODULO_BACKTRACK_ATTEMPTS,
176 "max-modulo-backtrack-attempts",
177 "The maximum number of backtrack attempts the scheduler should make when modulo scheduling a loop",
180 DEFPARAM(PARAM_LARGE_FUNCTION_INSNS,
181 "large-function-insns",
182 "The size of function body to be considered large",
184 DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH,
185 "large-function-growth",
186 "Maximal growth due to inlining of large function (in percent)",
188 DEFPARAM(PARAM_LARGE_UNIT_INSNS,
190 "The size of translation unit to be considered large",
192 DEFPARAM(PARAM_INLINE_UNIT_GROWTH,
193 "inline-unit-growth",
194 "How much can given compilation unit grow because of the inlining (in percent)",
196 DEFPARAM(PARAM_IPCP_UNIT_GROWTH,
198 "How much can given compilation unit grow because of the interprocedural constant propagation (in percent)",
200 DEFPARAM(PARAM_EARLY_INLINING_INSNS,
201 "early-inlining-insns",
202 "Maximal estimated growth of function body caused by early inlining of single call",
204 DEFPARAM(PARAM_LARGE_STACK_FRAME,
206 "The size of stack frame to be considered large",
208 DEFPARAM(PARAM_STACK_FRAME_GROWTH,
209 "large-stack-frame-growth",
210 "Maximal stack frame growth due to inlining (in percent)",
213 /* The GCSE optimization will be disabled if it would require
214 significantly more memory than this value. */
215 DEFPARAM(PARAM_MAX_GCSE_MEMORY,
217 "The maximum amount of memory to be allocated by GCSE",
218 50 * 1024 * 1024, 0, 0)
220 /* The GCSE optimization of an expression will avoided if the ratio of
221 insertions to deletions is greater than this value. */
222 DEFPARAM(PARAM_MAX_GCSE_INSERTION_RATIO,
223 "max-gcse-insertion-ratio",
224 "The maximum ratio of insertions to deletions of expressions in GCSE",
227 /* This is the threshold ratio when to perform partial redundancy
228 elimination after reload. We perform partial redundancy elimination
229 when the following holds:
230 (Redundant load execution count)
231 ------------------------------- >= GCSE_AFTER_RELOAD_PARTIAL_FRACTION
232 (Added loads execution count) */
233 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_PARTIAL_FRACTION,
234 "gcse-after-reload-partial-fraction",
235 "The threshold ratio for performing partial redundancy elimination after reload",
237 /* This is the threshold ratio of the critical edges execution count compared to
238 the redundant loads execution count that permits performing the load
239 redundancy elimination in gcse after reload. */
240 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_CRITICAL_FRACTION,
241 "gcse-after-reload-critical-fraction",
242 "The threshold ratio of critical edges execution count that permit performing redundancy elimination after reload",
245 /* GCSE will use GCSE_COST_DISTANCE_RATION as a scaling factor
246 to calculate maximum distance for which an expression is allowed to move
247 from its rtx_cost. */
248 DEFPARAM(PARAM_GCSE_COST_DISTANCE_RATIO,
249 "gcse-cost-distance-ratio",
250 "Scaling factor in calculation of maximum distance an expression can be moved by GCSE optimizations",
252 /* GCSE won't restrict distance for which an expression with rtx_cost greater
253 than COSTS_N_INSN(GCSE_UNRESTRICTED_COST) is allowed to move. */
254 DEFPARAM(PARAM_GCSE_UNRESTRICTED_COST,
255 "gcse-unrestricted-cost",
256 "Cost at which GCSE optimizations will not constraint the distance an expression can travel",
259 /* How deep from a given basic block the dominator tree should be searched
260 for expressions to hoist to the block. The value of 0 will avoid limiting
262 DEFPARAM(PARAM_MAX_HOIST_DEPTH,
264 "Maximum depth of search in the dominator tree for expressions to hoist",
267 /* This parameter limits the number of insns in a loop that will be unrolled,
268 and by how much the loop is unrolled.
270 This limit should be at most half of the peeling limits: loop unroller
271 decides to not unroll loops that iterate fewer than 2*number of allowed
272 unrollings and thus we would have loops that are neither peeled or unrolled
274 DEFPARAM(PARAM_MAX_UNROLLED_INSNS,
275 "max-unrolled-insns",
276 "The maximum number of instructions to consider to unroll in a loop",
278 /* This parameter limits how many times the loop is unrolled depending
279 on number of insns really executed in each iteration. */
280 DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS,
281 "max-average-unrolled-insns",
282 "The maximum number of instructions to consider to unroll in a loop on average",
284 /* The maximum number of unrollings of a single loop. */
285 DEFPARAM(PARAM_MAX_UNROLL_TIMES,
287 "The maximum number of unrollings of a single loop",
289 /* The maximum number of insns of a peeled loop. */
290 DEFPARAM(PARAM_MAX_PEELED_INSNS,
292 "The maximum number of insns of a peeled loop",
294 /* The maximum number of peelings of a single loop. */
295 DEFPARAM(PARAM_MAX_PEEL_TIMES,
297 "The maximum number of peelings of a single loop",
299 /* The maximum number of peelings of a single loop that is peeled completely. */
300 DEFPARAM(PARAM_MAX_PEEL_BRANCHES,
302 "The maximum number of branches on the path through the peeled sequence",
304 /* The maximum number of insns of a peeled loop. */
305 DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS,
306 "max-completely-peeled-insns",
307 "The maximum number of insns of a completely peeled loop",
309 /* The maximum number of peelings of a single loop that is peeled completely. */
310 DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES,
311 "max-completely-peel-times",
312 "The maximum number of peelings of a single loop that is peeled completely",
314 /* The maximum number of insns of a peeled loop that rolls only once. */
315 DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS,
316 "max-once-peeled-insns",
317 "The maximum number of insns of a peeled loop that rolls only once",
319 /* The maximum depth of a loop nest we completely peel. */
320 DEFPARAM(PARAM_MAX_UNROLL_ITERATIONS,
321 "max-completely-peel-loop-nest-depth",
322 "The maximum depth of a loop nest we completely peel",
325 /* The maximum number of insns of an unswitched loop. */
326 DEFPARAM(PARAM_MAX_UNSWITCH_INSNS,
327 "max-unswitch-insns",
328 "The maximum number of insns of an unswitched loop",
330 /* The maximum level of recursion in unswitch_single_loop. */
331 DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL,
332 "max-unswitch-level",
333 "The maximum number of unswitchings in a single loop",
336 /* The maximum number of iterations of a loop the brute force algorithm
337 for analysis of # of iterations of the loop tries to evaluate. */
338 DEFPARAM(PARAM_MAX_ITERATIONS_TO_TRACK,
339 "max-iterations-to-track",
340 "Bound on the number of iterations the brute force # of iterations analysis algorithm evaluates",
342 /* A cutoff to avoid costly computations of the number of iterations in
343 the doloop transformation. */
344 DEFPARAM(PARAM_MAX_ITERATIONS_COMPUTATION_COST,
345 "max-iterations-computation-cost",
346 "Bound on the cost of an expression to compute the number of iterations",
349 /* This parameter is used to tune SMS MAX II calculations. */
350 DEFPARAM(PARAM_SMS_MAX_II_FACTOR,
352 "A factor for tuning the upper bound that swing modulo scheduler uses for scheduling a loop",
354 /* The minimum value of stage count that swing modulo scheduler will generate. */
355 DEFPARAM(PARAM_SMS_MIN_SC,
357 "The minimum value of stage count that swing modulo scheduler will generate.",
359 DEFPARAM(PARAM_SMS_DFA_HISTORY,
361 "The number of cycles the swing modulo scheduler considers when checking conflicts using DFA",
363 DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD,
364 "sms-loop-average-count-threshold",
365 "A threshold on the average loop count considered by the swing modulo scheduler",
368 DEFPARAM(HOT_BB_COUNT_FRACTION,
369 "hot-bb-count-fraction",
370 "Select fraction of the maximal count of repetitions of basic block in program given basic block needs to have to be considered hot",
372 DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
373 "hot-bb-frequency-fraction",
374 "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot",
377 DEFPARAM (PARAM_ALIGN_THRESHOLD,
379 "Select fraction of the maximal frequency of executions of basic block in function given basic block get alignment",
382 DEFPARAM (PARAM_ALIGN_LOOP_ITERATIONS,
383 "align-loop-iterations",
384 "Loops iterating at least selected number of iterations will get loop alignement.",
387 /* For guessed profiles, the loops having unknown number of iterations
388 are predicted to iterate relatively few (10) times at average.
389 For functions containing one loop with large known number of iterations
390 and other loops having unbounded loops we would end up predicting all
391 the other loops cold that is not usually the case. So we need to artificially
394 We need to cut the maximal predicted iterations to large enough iterations
395 so the loop appears important, but safely within HOT_BB_COUNT_FRACTION
398 DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS,
399 "max-predicted-iterations",
400 "The maximum number of loop iterations we predict statically",
402 DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
403 "tracer-dynamic-coverage-feedback",
404 "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available",
406 DEFPARAM(TRACER_DYNAMIC_COVERAGE,
407 "tracer-dynamic-coverage",
408 "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available",
410 DEFPARAM(TRACER_MAX_CODE_GROWTH,
411 "tracer-max-code-growth",
412 "Maximal code growth caused by tail duplication (in percent)",
414 DEFPARAM(TRACER_MIN_BRANCH_RATIO,
415 "tracer-min-branch-ratio",
416 "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent)",
418 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
419 "tracer-min-branch-probability-feedback",
420 "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available",
422 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
423 "tracer-min-branch-probability",
424 "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available",
427 /* The maximum number of incoming edges to consider for crossjumping. */
428 DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
429 "max-crossjump-edges",
430 "The maximum number of incoming edges to consider for crossjumping",
433 /* The minimum number of matching instructions to consider for crossjumping. */
434 DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS,
435 "min-crossjump-insns",
436 "The minimum number of matching instructions to consider for crossjumping",
439 /* The maximum number expansion factor when copying basic blocks. */
440 DEFPARAM(PARAM_MAX_GROW_COPY_BB_INSNS,
441 "max-grow-copy-bb-insns",
442 "The maximum expansion factor when copying basic blocks",
445 /* The maximum number of insns to duplicate when unfactoring computed gotos. */
446 DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS,
447 "max-goto-duplication-insns",
448 "The maximum number of insns to duplicate when unfactoring computed gotos",
451 /* The maximum length of path considered in cse. */
452 DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
453 "max-cse-path-length",
454 "The maximum length of path considered in cse",
456 DEFPARAM(PARAM_MAX_CSE_INSNS,
458 "The maximum instructions CSE process before flushing",
461 /* The cost of expression in loop invariant motion that is considered
463 DEFPARAM(PARAM_LIM_EXPENSIVE,
465 "The minimum cost of an expensive expression in the loop invariant motion",
468 /* Bound on number of candidates for induction variables below that
469 all candidates are considered for each use in induction variable
472 DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND,
473 "iv-consider-all-candidates-bound",
474 "Bound on number of candidates below that all candidates are considered in iv optimizations",
477 /* The induction variable optimizations give up on loops that contain more
478 induction variable uses. */
480 DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES,
481 "iv-max-considered-uses",
482 "Bound on number of iv uses in loop optimized in iv optimizations",
485 /* If there are at most this number of ivs in the set, try removing unnecessary
486 ivs from the set always. */
488 DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND,
489 "iv-always-prune-cand-set-bound",
490 "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization",
493 DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE,
494 "scev-max-expr-size",
495 "Bound on size of expressions used in the scalar evolutions analyzer",
498 DEFPARAM(PARAM_SCEV_MAX_EXPR_COMPLEXITY,
499 "scev-max-expr-complexity",
500 "Bound on the complexity of the expressions in the scalar evolutions analyzer",
503 DEFPARAM(PARAM_OMEGA_MAX_VARS,
505 "Bound on the number of variables in Omega constraint systems",
508 DEFPARAM(PARAM_OMEGA_MAX_GEQS,
510 "Bound on the number of inequalities in Omega constraint systems",
513 DEFPARAM(PARAM_OMEGA_MAX_EQS,
515 "Bound on the number of equalities in Omega constraint systems",
518 DEFPARAM(PARAM_OMEGA_MAX_WILD_CARDS,
519 "omega-max-wild-cards",
520 "Bound on the number of wild cards in Omega constraint systems",
523 DEFPARAM(PARAM_OMEGA_HASH_TABLE_SIZE,
524 "omega-hash-table-size",
525 "Bound on the size of the hash table in Omega constraint systems",
528 DEFPARAM(PARAM_OMEGA_MAX_KEYS,
530 "Bound on the number of keys in Omega constraint systems",
533 DEFPARAM(PARAM_OMEGA_ELIMINATE_REDUNDANT_CONSTRAINTS,
534 "omega-eliminate-redundant-constraints",
535 "When set to 1, use expensive methods to eliminate all redundant constraints",
538 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIGNMENT_CHECKS,
539 "vect-max-version-for-alignment-checks",
540 "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alignment check",
543 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS,
544 "vect-max-version-for-alias-checks",
545 "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alias check",
548 DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS,
549 "max-cselib-memory-locations",
550 "The maximum memory locations recorded by cselib",
553 #ifdef ENABLE_GC_ALWAYS_COLLECT
554 # define GGC_MIN_EXPAND_DEFAULT 0
555 # define GGC_MIN_HEAPSIZE_DEFAULT 0
557 # define GGC_MIN_EXPAND_DEFAULT 30
558 # define GGC_MIN_HEAPSIZE_DEFAULT 4096
561 DEFPARAM(GGC_MIN_EXPAND,
563 "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap",
564 GGC_MIN_EXPAND_DEFAULT, 0, 0)
566 DEFPARAM(GGC_MIN_HEAPSIZE,
568 "Minimum heap size before we start collecting garbage, in kilobytes",
569 GGC_MIN_HEAPSIZE_DEFAULT, 0, 0)
571 #undef GGC_MIN_EXPAND_DEFAULT
572 #undef GGC_MIN_HEAPSIZE_DEFAULT
574 DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
575 "max-reload-search-insns",
576 "The maximum number of instructions to search backward when looking for equivalent reload",
579 DEFPARAM(PARAM_SINK_FREQUENCY_THRESHOLD,
580 "sink-frequency-threshold",
581 "Target block's relative execution frequency (as a percentage) required to sink a statement",
584 DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS,
585 "max-sched-region-blocks",
586 "The maximum number of blocks in a region to be considered for interblock scheduling",
589 DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS,
590 "max-sched-region-insns",
591 "The maximum number of insns in a region to be considered for interblock scheduling",
594 DEFPARAM(PARAM_MAX_PIPELINE_REGION_BLOCKS,
595 "max-pipeline-region-blocks",
596 "The maximum number of blocks in a region to be considered for interblock scheduling",
599 DEFPARAM(PARAM_MAX_PIPELINE_REGION_INSNS,
600 "max-pipeline-region-insns",
601 "The maximum number of insns in a region to be considered for interblock scheduling",
604 DEFPARAM(PARAM_MIN_SPEC_PROB,
606 "The minimum probability of reaching a source block for interblock speculative scheduling",
609 DEFPARAM(PARAM_MAX_SCHED_EXTEND_REGIONS_ITERS,
610 "max-sched-extend-regions-iters",
611 "The maximum number of iterations through CFG to extend regions",
614 DEFPARAM(PARAM_MAX_SCHED_INSN_CONFLICT_DELAY,
615 "max-sched-insn-conflict-delay",
616 "The maximum conflict delay for an insn to be considered for speculative motion",
619 DEFPARAM(PARAM_SCHED_SPEC_PROB_CUTOFF,
620 "sched-spec-prob-cutoff",
621 "The minimal probability of speculation success (in percents), so that speculative insn will be scheduled.",
624 DEFPARAM(PARAM_SCHED_STATE_EDGE_PROB_CUTOFF,
625 "sched-state-edge-prob-cutoff",
626 "The minimum probability an edge must have for the scheduler to save its state across it.",
629 DEFPARAM(PARAM_SELSCHED_MAX_LOOKAHEAD,
630 "selsched-max-lookahead",
631 "The maximum size of the lookahead window of selective scheduling",
634 DEFPARAM(PARAM_SELSCHED_MAX_SCHED_TIMES,
635 "selsched-max-sched-times",
636 "Maximum number of times that an insn could be scheduled",
639 DEFPARAM(PARAM_SELSCHED_INSNS_TO_RENAME,
640 "selsched-insns-to-rename",
641 "Maximum number of instructions in the ready list that are considered eligible for renaming",
644 DEFPARAM (PARAM_SCHED_MEM_TRUE_DEP_COST,
645 "sched-mem-true-dep-cost",
646 "Minimal distance between possibly conflicting store and load",
649 DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
650 "max-last-value-rtl",
651 "The maximum number of RTL nodes that can be recorded as combiner's last value",
654 /* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
655 {signed,unsigned} integral types. This determines N.
656 Experimentation shows 251 to be a good value that generates the
657 least amount of garbage for allocating the TREE_VEC storage. */
658 DEFPARAM (PARAM_INTEGER_SHARE_LIMIT,
659 "integer-share-limit",
660 "The upper bound for sharing integer constants",
663 DEFPARAM (PARAM_SSP_BUFFER_SIZE,
665 "The lower bound for a buffer to be considered for stack smashing protection",
668 /* When we thread through a block we have to make copies of the
669 statements within the block. Clearly for large blocks the code
672 PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number
673 of statements and PHI nodes allowed in a block which is going to
674 be duplicated for thread jumping purposes.
676 Some simple analysis showed that more than 99% of the jump
677 threading opportunities are for blocks with less than 15
678 statements. So we can get the benefits of jump threading
679 without excessive code bloat for pathological cases with the
680 throttle set at 15 statements. */
681 DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS,
682 "max-jump-thread-duplication-stmts",
683 "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps",
686 /* This is the maximum number of fields a variable may have before the pointer analysis machinery
687 will stop trying to treat it in a field-sensitive manner.
688 There are programs out there with thousands of fields per structure, and handling them
689 field-sensitively is not worth the cost. */
690 DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE,
691 "max-fields-for-field-sensitive",
692 "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable",
695 DEFPARAM(PARAM_MAX_SCHED_READY_INSNS,
696 "max-sched-ready-insns",
697 "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass",
700 /* This is the maximum number of active local stores RTL DSE will consider. */
701 DEFPARAM (PARAM_MAX_DSE_ACTIVE_LOCAL_STORES,
702 "max-dse-active-local-stores",
703 "Maximum number of active local stores in RTL dead store elimination",
706 /* Prefetching and cache-optimizations related parameters. Default values are
707 usually set by machine description. */
709 /* The number of insns executed before prefetch is completed. */
711 DEFPARAM (PARAM_PREFETCH_LATENCY,
713 "The number of insns executed before prefetch is completed",
716 /* The number of prefetches that can run at the same time. */
718 DEFPARAM (PARAM_SIMULTANEOUS_PREFETCHES,
719 "simultaneous-prefetches",
720 "The number of prefetches that can run at the same time",
723 /* The size of L1 cache in kB. */
725 DEFPARAM (PARAM_L1_CACHE_SIZE,
727 "The size of L1 cache",
730 /* The size of L1 cache line in bytes. */
732 DEFPARAM (PARAM_L1_CACHE_LINE_SIZE,
733 "l1-cache-line-size",
734 "The size of L1 cache line",
737 /* The size of L2 cache in kB. */
739 DEFPARAM (PARAM_L2_CACHE_SIZE,
741 "The size of L2 cache",
744 /* Whether we should use canonical types rather than deep "structural"
745 type checking. Setting this value to 1 (the default) improves
746 compilation performance in the C++ and Objective-C++ front end;
747 this value should only be set to zero to work around bugs in the
748 canonical type system by disabling it. */
750 DEFPARAM (PARAM_USE_CANONICAL_TYPES,
751 "use-canonical-types",
752 "Whether to use canonical types",
755 DEFPARAM (PARAM_MAX_PARTIAL_ANTIC_LENGTH,
756 "max-partial-antic-length",
757 "Maximum length of partial antic set when performing tree pre optimization",
760 /* The following is used as a stop-gap limit for cases where really huge
761 SCCs blow up memory and compile-time use too much. If we hit this limit,
762 SCCVN and such FRE and PRE will be not done at all for the current
765 DEFPARAM (PARAM_SCCVN_MAX_SCC_SIZE,
766 "sccvn-max-scc-size",
767 "Maximum size of a SCC before SCCVN stops processing a function",
770 /* The following is used as a stop-gap limit for cases where really huge
771 functions blow up compile-time use too much. It limits the number of
772 alias-queries we do for finding common subexpressions for memory loads and
773 stores. The number of alias-queries is otherwise limited by the number of
774 stores on paths to function entry. */
776 DEFPARAM (PARAM_SCCVN_MAX_ALIAS_QUERIES_PER_ACCESS,
777 "sccvn-max-alias-queries-per-access",
778 "Maximum number of disambiguations to perform per memory access",
781 DEFPARAM (PARAM_IRA_MAX_LOOPS_NUM,
783 "Max loops number for regional RA",
786 DEFPARAM (PARAM_IRA_MAX_CONFLICT_TABLE_SIZE,
787 "ira-max-conflict-table-size",
788 "Max size of conflict table in MB",
791 DEFPARAM (PARAM_IRA_LOOP_RESERVED_REGS,
792 "ira-loop-reserved-regs",
793 "The number of registers in each class kept unused by loop invariant motion",
796 /* Switch initialization conversion will refuse to create arrays that are
797 bigger than this parameter times the number of switch branches. */
799 DEFPARAM (PARAM_SWITCH_CONVERSION_BRANCH_RATIO,
800 "switch-conversion-max-branch-ratio",
801 "The maximum ratio between array size and switch branches for "
802 "a switch conversion to take place",
805 /* Size of tiles when doing loop blocking. */
807 DEFPARAM (PARAM_LOOP_BLOCK_TILE_SIZE,
808 "loop-block-tile-size",
809 "size of tiles for loop blocking",
812 /* Maximal number of parameters that we allow in a SCoP. */
814 DEFPARAM (PARAM_GRAPHITE_MAX_NB_SCOP_PARAMS,
815 "graphite-max-nb-scop-params",
816 "maximum number of parameters in a SCoP",
819 /* Maximal number of basic blocks in the functions analyzed by Graphite. */
821 DEFPARAM (PARAM_GRAPHITE_MAX_BBS_PER_FUNCTION,
822 "graphite-max-bbs-per-function",
823 "maximum number of basic blocks per function to be analyzed by Graphite",
826 /* Avoid data dependence analysis on very large loops. */
827 DEFPARAM (PARAM_LOOP_MAX_DATAREFS_FOR_DATADEPS,
828 "loop-max-datarefs-for-datadeps",
829 "Maximum number of datarefs in loop for building loop data dependencies",
832 /* Avoid doing loop invariant motion on very large loops. */
834 DEFPARAM (PARAM_LOOP_INVARIANT_MAX_BBS_IN_LOOP,
835 "loop-invariant-max-bbs-in-loop",
836 "Max basic blocks number in loop for loop invariant motion",
839 /* Avoid SLP vectorization of large basic blocks. */
840 DEFPARAM (PARAM_SLP_MAX_INSNS_IN_BB,
841 "slp-max-insns-in-bb",
842 "Maximum number of instructions in basic block to be considered for SLP vectorization",
845 DEFPARAM (PARAM_MIN_INSN_TO_PREFETCH_RATIO,
846 "min-insn-to-prefetch-ratio",
847 "Min. ratio of insns to prefetches to enable prefetching for "
848 "a loop with an unknown trip count",
851 DEFPARAM (PARAM_PREFETCH_MIN_INSN_TO_MEM_RATIO,
852 "prefetch-min-insn-to-mem-ratio",
853 "Min. ratio of insns to mem ops to enable prefetching in a loop",
856 /* Set maximum hash table size for var tracking. */
858 DEFPARAM (PARAM_MAX_VARTRACK_SIZE,
860 "Max. size of var tracking hash tables",
863 /* Set maximum recursion depth for var tracking expression expansion
866 DEFPARAM (PARAM_MAX_VARTRACK_EXPR_DEPTH,
867 "max-vartrack-expr-depth",
868 "Max. recursion depth for expanding var tracking expressions",
871 /* Set minimum insn uid for non-debug insns. */
873 DEFPARAM (PARAM_MIN_NONDEBUG_INSN_UID,
874 "min-nondebug-insn-uid",
875 "The minimum UID to be used for a nondebug insn",
878 DEFPARAM (PARAM_IPA_SRA_PTR_GROWTH_FACTOR,
879 "ipa-sra-ptr-growth-factor",
880 "Maximum allowed growth of size of new parameters ipa-sra replaces "
881 "a pointer to an aggregate with",
884 DEFPARAM (PARAM_TM_MAX_AGGREGATE_SIZE,
885 "tm-max-aggregate-size",
886 "Size in bytes after which thread-local aggregates should be "
887 "instrumented with the logging functions instead of save/restore "
891 DEFPARAM (PARAM_IPA_CP_VALUE_LIST_SIZE,
892 "ipa-cp-value-list-size",
893 "Maximum size of a list of values associated with each parameter for "
894 "interprocedural constant propagation",
897 DEFPARAM (PARAM_IPA_CP_EVAL_THRESHOLD,
898 "ipa-cp-eval-threshold",
899 "Threshold ipa-cp opportunity evaluation that is still considered "
900 "beneficial to clone.",
903 DEFPARAM (PARAM_IPA_MAX_AGG_ITEMS,
905 "Maximum number of aggregate content items for a parameter in "
906 "jump functions and lattices",
909 DEFPARAM (PARAM_IPA_CP_LOOP_HINT_BONUS,
910 "ipa-cp-loop-hint-bonus",
911 "Compile-time bonus IPA-CP assigns to candidates which make loop "
912 "bounds or strides known.",
915 /* WHOPR partitioning configuration. */
917 DEFPARAM (PARAM_LTO_PARTITIONS,
919 "Number of partitions the program should be split to",
922 DEFPARAM (MIN_PARTITION_SIZE,
924 "Minimal size of a partition for LTO (in estimated instructions)",
927 /* Diagnostic parameters. */
929 DEFPARAM (CXX_MAX_NAMESPACES_FOR_DIAGNOSTIC_HELP,
930 "cxx-max-namespaces-for-diagnostic-help",
931 "Maximum number of namespaces to search for alternatives when "
935 /* Maximum number of conditional store pairs that can be sunk. */
936 DEFPARAM (PARAM_MAX_STORES_TO_SINK,
937 "max-stores-to-sink",
938 "Maximum number of conditional store pairs that can be sunk",
941 /* Override CASE_VALUES_THRESHOLD of when to switch from doing switch
942 statements via if statements to using a table jump operation. If the value
943 is 0, the default CASE_VALUES_THRESHOLD will be used. */
944 DEFPARAM (PARAM_CASE_VALUES_THRESHOLD,
945 "case-values-threshold",
946 "The smallest number of different values for which it is best to "
947 "use a jump-table instead of a tree of conditional branches, "
948 "if 0, use the default for the machine",
951 /* Data race flags for C++0x memory model compliance. */
952 DEFPARAM (PARAM_ALLOW_LOAD_DATA_RACES,
953 "allow-load-data-races",
954 "Allow new data races on loads to be introduced",
957 DEFPARAM (PARAM_ALLOW_STORE_DATA_RACES,
958 "allow-store-data-races",
959 "Allow new data races on stores to be introduced",
962 DEFPARAM (PARAM_ALLOW_PACKED_LOAD_DATA_RACES,
963 "allow-packed-load-data-races",
964 "Allow new data races on packed data loads to be introduced",
967 DEFPARAM (PARAM_ALLOW_PACKED_STORE_DATA_RACES,
968 "allow-packed-store-data-races",
969 "Allow new data races on packed data stores to be introduced",
972 /* Reassociation width to be used by tree reassoc optimization. */
973 DEFPARAM (PARAM_TREE_REASSOC_WIDTH,
974 "tree-reassoc-width",
975 "Set the maximum number of instructions executed in parallel in "
976 "reassociated tree. If 0, use the target dependent heuristic.",
979 DEFPARAM (PARAM_MAX_TAIL_MERGE_COMPARISONS,
980 "max-tail-merge-comparisons",
981 "Maximum amount of similar bbs to compare a bb with",
984 DEFPARAM (PARAM_MAX_TAIL_MERGE_ITERATIONS,
985 "max-tail-merge-iterations",
986 "Maximum amount of iterations of the pass over a function",
989 /* Maximum number of strings for which strlen optimization pass will
990 track string lenths. */
991 DEFPARAM (PARAM_MAX_TRACKED_STRLENS,
992 "max-tracked-strlens",
993 "Maximum number of strings for which strlen optimization pass will "
994 "track string lengths",
997 /* Keep this in sync with the sched_pressure_algorithm enum. */
998 DEFPARAM (PARAM_SCHED_PRESSURE_ALGORITHM,
999 "sched-pressure-algorithm",
1000 "Which -fsched-pressure algorithm to apply",
1003 /* Maximum length of candidate scans in straight-line strength reduction. */
1004 DEFPARAM (PARAM_MAX_SLSR_CANDIDATE_SCAN,
1005 "max-slsr-cand-scan",
1006 "Maximum length of candidate scans for straight-line "
1007 "strength reduction",