1 /* params.def - Run-time parameters.
2 Copyright (C) 2001-2016 Free Software Foundation, Inc.
3 Written by Mark Mitchell <mark@codesourcery.com>.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
21 /* This file contains definitions for language-independent
22 parameters. The DEFPARAM macro takes 6 arguments:
24 - The enumeral corresponding to this parameter.
26 - The name that can be used to set this parameter using the
27 command-line option `--param <name>=<value>'.
29 - A help string explaining how the parameter is used.
31 - A default value for the parameter.
33 - The minimum acceptable value for the parameter.
35 - The maximum acceptable value for the parameter (if greater than
38 The DEFPARAMENUM<N> macro is similar, but instead of the minumum and maximum
39 arguments, it contains a list of <N> allowed strings, corresponding to
40 integer values 0..<N>-1. Note that the default argument needs to be
41 specified as one of the allowed strings, rather than an integer value.
43 Be sure to add an entry to invoke.texi summarizing the parameter. */
45 /* When branch is predicted to be taken with probability lower than this
46 threshold (in percent), then it is considered well predictable. */
47 DEFPARAM (PARAM_PREDICTABLE_BRANCH_OUTCOME,
48 "predictable-branch-outcome",
49 "Maximal estimated outcome of branch considered predictable.",
52 DEFPARAM (PARAM_INLINE_MIN_SPEEDUP,
54 "The minimal estimated speedup allowing inliner to ignore inline-insns-single and inline-isnsns-auto.",
57 /* The single function inlining limit. This is the maximum size
58 of a function counted in internal gcc instructions (not in
59 real machine instructions) that is eligible for inlining
61 The default value is 450.
62 Only functions marked inline (or methods defined in the class
63 definition for C++) are affected by this.
64 There are more restrictions to inlining: If inlined functions
65 call other functions, the already inlined instructions are
66 counted and once the recursive inline limit (see
67 "max-inline-insns" parameter) is exceeded, the acceptable size
69 DEFPARAM (PARAM_MAX_INLINE_INSNS_SINGLE,
70 "max-inline-insns-single",
71 "The maximum number of instructions in a single function eligible for inlining.",
74 /* The single function inlining limit for functions that are
75 inlined by virtue of -finline-functions (-O3).
76 This limit should be chosen to be below or equal to the limit
77 that is applied to functions marked inlined (or defined in the
78 class declaration in C++) given by the "max-inline-insns-single"
80 The default value is 40. */
81 DEFPARAM (PARAM_MAX_INLINE_INSNS_AUTO,
82 "max-inline-insns-auto",
83 "The maximum number of instructions when automatically inlining.",
86 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE,
87 "max-inline-insns-recursive",
88 "The maximum number of instructions inline function can grow to via recursive inlining.",
91 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO,
92 "max-inline-insns-recursive-auto",
93 "The maximum number of instructions non-inline function can grow to via recursive inlining.",
96 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH,
97 "max-inline-recursive-depth",
98 "The maximum depth of recursive inlining for inline functions.",
101 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO,
102 "max-inline-recursive-depth-auto",
103 "The maximum depth of recursive inlining for non-inline functions.",
106 DEFPARAM (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY,
107 "min-inline-recursive-probability",
108 "Inline recursively only when the probability of call being executed exceeds the parameter.",
111 /* Limit of iterations of early inliner. This basically bounds number of
112 nested indirect calls early inliner can resolve. Deeper chains are still
113 handled by late inlining. */
114 DEFPARAM (PARAM_EARLY_INLINER_MAX_ITERATIONS,
115 "max-early-inliner-iterations",
116 "The maximum number of nested indirect inlining performed by early inliner.",
119 /* Limit on probability of entry BB. */
120 DEFPARAM (PARAM_COMDAT_SHARING_PROBABILITY,
121 "comdat-sharing-probability",
122 "Probability that COMDAT function will be shared with different compilation unit.",
125 /* Limit on probability of entry BB. */
126 DEFPARAM (PARAM_PARTIAL_INLINING_ENTRY_PROBABILITY,
127 "partial-inlining-entry-probability",
128 "Maximum probability of the entry BB of split region (in percent relative to entry BB of the function) to make partial inlining happen.",
131 /* Limit the number of expansions created by the variable expansion
132 optimization to avoid register pressure. */
133 DEFPARAM (PARAM_MAX_VARIABLE_EXPANSIONS,
134 "max-variable-expansions-in-unroller",
135 "If -fvariable-expansion-in-unroller is used, the maximum number of times that an individual variable will be expanded during loop unrolling.",
138 /* Limit loop autovectorization to loops with large enough iteration count. */
139 DEFPARAM (PARAM_MIN_VECT_LOOP_BOUND,
140 "min-vect-loop-bound",
141 "If -ftree-vectorize is used, the minimal loop bound of a loop to be considered for vectorization.",
144 /* The maximum number of instructions to consider when looking for an
145 instruction to fill a delay slot. If more than this arbitrary
146 number of instructions is searched, the time savings from filling
147 the delay slot will be minimal so stop searching. Increasing
148 values mean more aggressive optimization, making the compile time
149 increase with probably small improvement in executable run time. */
150 DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH,
151 "max-delay-slot-insn-search",
152 "The maximum number of instructions to consider to fill a delay slot.",
155 /* When trying to fill delay slots, the maximum number of instructions
156 to consider when searching for a block with valid live register
157 information. Increasing this arbitrarily chosen value means more
158 aggressive optimization, increasing the compile time. This
159 parameter should be removed when the delay slot code is rewritten
160 to maintain the control-flow graph. */
161 DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH,
162 "max-delay-slot-live-search",
163 "The maximum number of instructions to consider to find accurate live register information.",
166 /* This parameter limits the number of branch elements that the
167 scheduler will track anti-dependencies through without resetting
168 the tracking mechanism. Large functions with few calls or barriers
169 can generate lists containing many 1000's of dependencies. Generally
170 the compiler either uses all available memory, or runs for far too long. */
171 DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH,
172 "max-pending-list-length",
173 "The maximum length of scheduling's pending operations list.",
176 /* This parameter limits the number of backtracking attempts when using the
177 haifa scheduler for modulo scheduling. */
178 DEFPARAM(PARAM_MAX_MODULO_BACKTRACK_ATTEMPTS,
179 "max-modulo-backtrack-attempts",
180 "The maximum number of backtrack attempts the scheduler should make when modulo scheduling a loop.",
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.",
221 128 * 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.",
271 /* When synthesizing expnonentiation by a real constant operations using square
272 roots, this controls how deep sqrt chains we are willing to generate. */
273 DEFPARAM(PARAM_MAX_POW_SQRT_DEPTH,
274 "max-pow-sqrt-depth",
275 "Maximum depth of sqrt chains to use when synthesizing exponentiation by a real constant.",
278 /* This parameter limits the number of insns in a loop that will be unrolled,
279 and by how much the loop is unrolled.
281 This limit should be at most half of the peeling limits: loop unroller
282 decides to not unroll loops that iterate fewer than 2*number of allowed
283 unrollings and thus we would have loops that are neither peeled or unrolled
285 DEFPARAM(PARAM_MAX_UNROLLED_INSNS,
286 "max-unrolled-insns",
287 "The maximum number of instructions to consider to unroll in a loop.",
289 /* This parameter limits how many times the loop is unrolled depending
290 on number of insns really executed in each iteration. */
291 DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS,
292 "max-average-unrolled-insns",
293 "The maximum number of instructions to consider to unroll in a loop on average.",
295 /* The maximum number of unrollings of a single loop. */
296 DEFPARAM(PARAM_MAX_UNROLL_TIMES,
298 "The maximum number of unrollings of a single loop.",
300 /* The maximum number of insns of a peeled loop. */
301 DEFPARAM(PARAM_MAX_PEELED_INSNS,
303 "The maximum number of insns of a peeled loop.",
305 /* The maximum number of peelings of a single loop. */
306 DEFPARAM(PARAM_MAX_PEEL_TIMES,
308 "The maximum number of peelings of a single loop.",
310 /* The maximum number of peelings of a single loop that is peeled completely. */
311 DEFPARAM(PARAM_MAX_PEEL_BRANCHES,
313 "The maximum number of branches on the path through the peeled sequence.",
315 /* The maximum number of insns of a peeled loop. */
316 DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS,
317 "max-completely-peeled-insns",
318 "The maximum number of insns of a completely peeled loop.",
320 /* The maximum number of peelings of a single loop that is peeled completely. */
321 DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES,
322 "max-completely-peel-times",
323 "The maximum number of peelings of a single loop that is peeled completely.",
325 /* The maximum number of insns of a peeled loop that rolls only once. */
326 DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS,
327 "max-once-peeled-insns",
328 "The maximum number of insns of a peeled loop that rolls only once.",
330 /* The maximum depth of a loop nest we completely peel. */
331 DEFPARAM(PARAM_MAX_UNROLL_ITERATIONS,
332 "max-completely-peel-loop-nest-depth",
333 "The maximum depth of a loop nest we completely peel.",
336 /* The maximum number of insns of an unswitched loop. */
337 DEFPARAM(PARAM_MAX_UNSWITCH_INSNS,
338 "max-unswitch-insns",
339 "The maximum number of insns of an unswitched loop.",
341 /* The maximum level of recursion in unswitch_single_loop. */
342 DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL,
343 "max-unswitch-level",
344 "The maximum number of unswitchings in a single loop.",
347 /* The maximum number of iterations of a loop the brute force algorithm
348 for analysis of # of iterations of the loop tries to evaluate. */
349 DEFPARAM(PARAM_MAX_ITERATIONS_TO_TRACK,
350 "max-iterations-to-track",
351 "Bound on the number of iterations the brute force # of iterations analysis algorithm evaluates.",
353 /* A cutoff to avoid costly computations of the number of iterations in
354 the doloop transformation. */
355 DEFPARAM(PARAM_MAX_ITERATIONS_COMPUTATION_COST,
356 "max-iterations-computation-cost",
357 "Bound on the cost of an expression to compute the number of iterations.",
360 /* This parameter is used to tune SMS MAX II calculations. */
361 DEFPARAM(PARAM_SMS_MAX_II_FACTOR,
363 "A factor for tuning the upper bound that swing modulo scheduler uses for scheduling a loop.",
365 /* The minimum value of stage count that swing modulo scheduler will generate. */
366 DEFPARAM(PARAM_SMS_MIN_SC,
368 "The minimum value of stage count that swing modulo scheduler will generate.",
370 DEFPARAM(PARAM_SMS_DFA_HISTORY,
372 "The number of cycles the swing modulo scheduler considers when checking conflicts using DFA.",
374 DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD,
375 "sms-loop-average-count-threshold",
376 "A threshold on the average loop count considered by the swing modulo scheduler.",
379 DEFPARAM(HOT_BB_COUNT_WS_PERMILLE,
380 "hot-bb-count-ws-permille",
381 "A basic block profile count is considered hot if it contributes to "
382 "the given permillage of the entire profiled execution.",
384 DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
385 "hot-bb-frequency-fraction",
386 "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot.",
389 DEFPARAM(UNLIKELY_BB_COUNT_FRACTION,
390 "unlikely-bb-count-fraction",
391 "The minimum fraction of profile runs a given basic block execution count must be not to be considered unlikely.",
394 DEFPARAM (PARAM_ALIGN_THRESHOLD,
396 "Select fraction of the maximal frequency of executions of basic block in function given basic block get alignment.",
399 DEFPARAM (PARAM_ALIGN_LOOP_ITERATIONS,
400 "align-loop-iterations",
401 "Loops iterating at least selected number of iterations will get loop alignement..",
404 /* For guessed profiles, the loops having unknown number of iterations
405 are predicted to iterate relatively few (10) times at average.
406 For functions containing one loop with large known number of iterations
407 and other loops having unbounded loops we would end up predicting all
408 the other loops cold that is not usually the case. So we need to artificially
411 We need to cut the maximal predicted iterations to large enough iterations
412 so the loop appears important, but safely within maximum hotness
415 DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS,
416 "max-predicted-iterations",
417 "The maximum number of loop iterations we predict statically.",
420 /* This parameter controls the probability of builtin_expect. The default
421 value is 90%. This empirical value is obtained through the weighted
422 probability of FDO counters (with the FDO count value as the weight)
423 in some real world programs:
424 (1) Google performance test benchmarks: the probability is 0.9081.
425 (2) Linux 3.3 kernel running Google search workload: the probability
428 DEFPARAM(BUILTIN_EXPECT_PROBABILITY,
429 "builtin-expect-probability",
430 "Set the estimated probability in percentage for builtin expect. The default value is 90% probability.",
432 DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
433 "tracer-dynamic-coverage-feedback",
434 "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available.",
436 DEFPARAM(TRACER_DYNAMIC_COVERAGE,
437 "tracer-dynamic-coverage",
438 "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available.",
440 DEFPARAM(TRACER_MAX_CODE_GROWTH,
441 "tracer-max-code-growth",
442 "Maximal code growth caused by tail duplication (in percent).",
444 DEFPARAM(TRACER_MIN_BRANCH_RATIO,
445 "tracer-min-branch-ratio",
446 "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent).",
448 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
449 "tracer-min-branch-probability-feedback",
450 "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available.",
452 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
453 "tracer-min-branch-probability",
454 "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available.",
457 /* The maximum number of incoming edges to consider for crossjumping. */
458 DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
459 "max-crossjump-edges",
460 "The maximum number of incoming edges to consider for crossjumping.",
463 /* The minimum number of matching instructions to consider for crossjumping. */
464 DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS,
465 "min-crossjump-insns",
466 "The minimum number of matching instructions to consider for crossjumping.",
469 /* The maximum number expansion factor when copying basic blocks. */
470 DEFPARAM(PARAM_MAX_GROW_COPY_BB_INSNS,
471 "max-grow-copy-bb-insns",
472 "The maximum expansion factor when copying basic blocks.",
475 /* The maximum number of insns to duplicate when unfactoring computed gotos. */
476 DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS,
477 "max-goto-duplication-insns",
478 "The maximum number of insns to duplicate when unfactoring computed gotos.",
481 /* The maximum length of path considered in cse. */
482 DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
483 "max-cse-path-length",
484 "The maximum length of path considered in cse.",
486 DEFPARAM(PARAM_MAX_CSE_INSNS,
488 "The maximum instructions CSE process before flushing.",
491 /* The cost of expression in loop invariant motion that is considered
493 DEFPARAM(PARAM_LIM_EXPENSIVE,
495 "The minimum cost of an expensive expression in the loop invariant motion.",
498 /* Bound on number of candidates for induction variables below that
499 all candidates are considered for each use in induction variable
502 DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND,
503 "iv-consider-all-candidates-bound",
504 "Bound on number of candidates below that all candidates are considered in iv optimizations.",
507 /* The induction variable optimizations give up on loops that contain more
508 induction variable uses. */
510 DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES,
511 "iv-max-considered-uses",
512 "Bound on number of iv uses in loop optimized in iv optimizations.",
515 /* If there are at most this number of ivs in the set, try removing unnecessary
516 ivs from the set always. */
518 DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND,
519 "iv-always-prune-cand-set-bound",
520 "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization.",
523 DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE,
524 "scev-max-expr-size",
525 "Bound on size of expressions used in the scalar evolutions analyzer.",
528 DEFPARAM(PARAM_SCEV_MAX_EXPR_COMPLEXITY,
529 "scev-max-expr-complexity",
530 "Bound on the complexity of the expressions in the scalar evolutions analyzer.",
533 DEFPARAM (PARAM_MAX_TREE_IF_CONVERSION_PHI_ARGS,
534 "max-tree-if-conversion-phi-args",
535 "Maximum number of arguments in a PHI supported by TREE if-conversion "
536 "unless the loop is marked with simd pragma.",
539 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIGNMENT_CHECKS,
540 "vect-max-version-for-alignment-checks",
541 "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alignment check.",
544 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS,
545 "vect-max-version-for-alias-checks",
546 "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alias check.",
549 DEFPARAM(PARAM_VECT_MAX_PEELING_FOR_ALIGNMENT,
550 "vect-max-peeling-for-alignment",
551 "Max number of loop peels to enhancement alignment of data references in a loop.",
554 DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS,
555 "max-cselib-memory-locations",
556 "The maximum memory locations recorded by cselib.",
559 #ifdef ENABLE_GC_ALWAYS_COLLECT
560 # define GGC_MIN_EXPAND_DEFAULT 0
561 # define GGC_MIN_HEAPSIZE_DEFAULT 0
563 # define GGC_MIN_EXPAND_DEFAULT 30
564 # define GGC_MIN_HEAPSIZE_DEFAULT 4096
567 DEFPARAM(GGC_MIN_EXPAND,
569 "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap.",
570 GGC_MIN_EXPAND_DEFAULT, 0, 0)
572 DEFPARAM(GGC_MIN_HEAPSIZE,
574 "Minimum heap size before we start collecting garbage, in kilobytes.",
575 GGC_MIN_HEAPSIZE_DEFAULT, 0, 0)
577 #undef GGC_MIN_EXPAND_DEFAULT
578 #undef GGC_MIN_HEAPSIZE_DEFAULT
580 DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
581 "max-reload-search-insns",
582 "The maximum number of instructions to search backward when looking for equivalent reload.",
585 DEFPARAM(PARAM_SINK_FREQUENCY_THRESHOLD,
586 "sink-frequency-threshold",
587 "Target block's relative execution frequency (as a percentage) required to sink a statement.",
590 DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS,
591 "max-sched-region-blocks",
592 "The maximum number of blocks in a region to be considered for interblock scheduling.",
595 DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS,
596 "max-sched-region-insns",
597 "The maximum number of insns in a region to be considered for interblock scheduling.",
600 DEFPARAM(PARAM_MAX_PIPELINE_REGION_BLOCKS,
601 "max-pipeline-region-blocks",
602 "The maximum number of blocks in a region to be considered for interblock scheduling.",
605 DEFPARAM(PARAM_MAX_PIPELINE_REGION_INSNS,
606 "max-pipeline-region-insns",
607 "The maximum number of insns in a region to be considered for interblock scheduling.",
610 DEFPARAM(PARAM_MIN_SPEC_PROB,
612 "The minimum probability of reaching a source block for interblock speculative scheduling.",
615 DEFPARAM(PARAM_MAX_SCHED_EXTEND_REGIONS_ITERS,
616 "max-sched-extend-regions-iters",
617 "The maximum number of iterations through CFG to extend regions.",
620 DEFPARAM(PARAM_MAX_SCHED_INSN_CONFLICT_DELAY,
621 "max-sched-insn-conflict-delay",
622 "The maximum conflict delay for an insn to be considered for speculative motion.",
625 DEFPARAM(PARAM_SCHED_SPEC_PROB_CUTOFF,
626 "sched-spec-prob-cutoff",
627 "The minimal probability of speculation success (in percents), so that speculative insn will be scheduled.",
630 DEFPARAM(PARAM_SCHED_STATE_EDGE_PROB_CUTOFF,
631 "sched-state-edge-prob-cutoff",
632 "The minimum probability an edge must have for the scheduler to save its state across it.",
635 DEFPARAM(PARAM_SELSCHED_MAX_LOOKAHEAD,
636 "selsched-max-lookahead",
637 "The maximum size of the lookahead window of selective scheduling.",
640 DEFPARAM(PARAM_SELSCHED_MAX_SCHED_TIMES,
641 "selsched-max-sched-times",
642 "Maximum number of times that an insn could be scheduled.",
645 DEFPARAM(PARAM_SELSCHED_INSNS_TO_RENAME,
646 "selsched-insns-to-rename",
647 "Maximum number of instructions in the ready list that are considered eligible for renaming.",
650 DEFPARAM (PARAM_SCHED_MEM_TRUE_DEP_COST,
651 "sched-mem-true-dep-cost",
652 "Minimal distance between possibly conflicting store and load.",
655 DEFPARAM (PARAM_SCHED_AUTOPREF_QUEUE_DEPTH,
656 "sched-autopref-queue-depth",
657 "Hardware autoprefetcher scheduler model control flag. Number of lookahead cycles the model looks into; at '0' only enable instruction sorting heuristic. Disabled by default.",
660 DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
661 "max-last-value-rtl",
662 "The maximum number of RTL nodes that can be recorded as combiner's last value.",
665 DEFPARAM(PARAM_MAX_COMBINE_INSNS,
667 "The maximum number of insns combine tries to combine.",
670 /* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
671 {signed,unsigned} integral types. This determines N.
672 Experimentation shows 251 to be a good value that generates the
673 least amount of garbage for allocating the TREE_VEC storage. */
674 DEFPARAM (PARAM_INTEGER_SHARE_LIMIT,
675 "integer-share-limit",
676 "The upper bound for sharing integer constants.",
679 DEFPARAM (PARAM_SSP_BUFFER_SIZE,
681 "The lower bound for a buffer to be considered for stack smashing protection.",
684 DEFPARAM (PARAM_MIN_SIZE_FOR_STACK_SHARING,
685 "min-size-for-stack-sharing",
686 "The minimum size of variables taking part in stack slot sharing "
687 "when not optimizing.",
690 /* When we thread through a block we have to make copies of the
691 statements within the block. Clearly for large blocks the code
694 PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number
695 of statements and PHI nodes allowed in a block which is going to
696 be duplicated for thread jumping purposes.
698 Some simple analysis showed that more than 99% of the jump
699 threading opportunities are for blocks with less than 15
700 statements. So we can get the benefits of jump threading
701 without excessive code bloat for pathological cases with the
702 throttle set at 15 statements. */
703 DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS,
704 "max-jump-thread-duplication-stmts",
705 "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps.",
708 /* This is the maximum number of fields a variable may have before the pointer analysis machinery
709 will stop trying to treat it in a field-sensitive manner.
710 There are programs out there with thousands of fields per structure, and handling them
711 field-sensitively is not worth the cost. */
712 DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE,
713 "max-fields-for-field-sensitive",
714 "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable.",
717 DEFPARAM(PARAM_MAX_SCHED_READY_INSNS,
718 "max-sched-ready-insns",
719 "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass.",
722 /* This is the maximum number of active local stores RTL DSE will consider. */
723 DEFPARAM (PARAM_MAX_DSE_ACTIVE_LOCAL_STORES,
724 "max-dse-active-local-stores",
725 "Maximum number of active local stores in RTL dead store elimination.",
728 /* Prefetching and cache-optimizations related parameters. Default values are
729 usually set by machine description. */
731 /* The number of insns executed before prefetch is completed. */
733 DEFPARAM (PARAM_PREFETCH_LATENCY,
735 "The number of insns executed before prefetch is completed.",
738 /* The number of prefetches that can run at the same time. */
740 DEFPARAM (PARAM_SIMULTANEOUS_PREFETCHES,
741 "simultaneous-prefetches",
742 "The number of prefetches that can run at the same time.",
745 /* The size of L1 cache in kB. */
747 DEFPARAM (PARAM_L1_CACHE_SIZE,
749 "The size of L1 cache.",
752 /* The size of L1 cache line in bytes. */
754 DEFPARAM (PARAM_L1_CACHE_LINE_SIZE,
755 "l1-cache-line-size",
756 "The size of L1 cache line.",
759 /* The size of L2 cache in kB. */
761 DEFPARAM (PARAM_L2_CACHE_SIZE,
763 "The size of L2 cache.",
766 /* Whether we should use canonical types rather than deep "structural"
767 type checking. Setting this value to 1 (the default) improves
768 compilation performance in the C++ and Objective-C++ front end;
769 this value should only be set to zero to work around bugs in the
770 canonical type system by disabling it. */
772 DEFPARAM (PARAM_USE_CANONICAL_TYPES,
773 "use-canonical-types",
774 "Whether to use canonical types.",
777 DEFPARAM (PARAM_MAX_PARTIAL_ANTIC_LENGTH,
778 "max-partial-antic-length",
779 "Maximum length of partial antic set when performing tree pre optimization.",
782 /* The following is used as a stop-gap limit for cases where really huge
783 SCCs blow up memory and compile-time use too much. If we hit this limit,
784 SCCVN and such FRE and PRE will be not done at all for the current
787 DEFPARAM (PARAM_SCCVN_MAX_SCC_SIZE,
788 "sccvn-max-scc-size",
789 "Maximum size of a SCC before SCCVN stops processing a function.",
792 /* The following is used as a stop-gap limit for cases where really huge
793 functions blow up compile-time use too much. It limits the number of
794 alias-queries we do for finding common subexpressions for memory loads and
795 stores. The number of alias-queries is otherwise limited by the number of
796 stores on paths to function entry. */
798 DEFPARAM (PARAM_SCCVN_MAX_ALIAS_QUERIES_PER_ACCESS,
799 "sccvn-max-alias-queries-per-access",
800 "Maximum number of disambiguations to perform per memory access.",
803 DEFPARAM (PARAM_IRA_MAX_LOOPS_NUM,
805 "Max loops number for regional RA.",
808 DEFPARAM (PARAM_IRA_MAX_CONFLICT_TABLE_SIZE,
809 "ira-max-conflict-table-size",
810 "Max size of conflict table in MB.",
813 DEFPARAM (PARAM_IRA_LOOP_RESERVED_REGS,
814 "ira-loop-reserved-regs",
815 "The number of registers in each class kept unused by loop invariant motion.",
818 DEFPARAM (PARAM_LRA_MAX_CONSIDERED_RELOAD_PSEUDOS,
819 "lra-max-considered-reload-pseudos",
820 "The max number of reload pseudos which are considered during spilling a non-reload pseudo.",
823 DEFPARAM (PARAM_LRA_INHERITANCE_EBB_PROBABILITY_CUTOFF,
824 "lra-inheritance-ebb-probability-cutoff",
825 "Minimal fall-through edge probability in percentage used to add BB to inheritance EBB in LRA.",
828 /* Switch initialization conversion will refuse to create arrays that are
829 bigger than this parameter times the number of switch branches. */
831 DEFPARAM (PARAM_SWITCH_CONVERSION_BRANCH_RATIO,
832 "switch-conversion-max-branch-ratio",
833 "The maximum ratio between array size and switch branches for "
834 "a switch conversion to take place.",
837 /* Size of tiles when doing loop blocking. */
839 DEFPARAM (PARAM_LOOP_BLOCK_TILE_SIZE,
840 "loop-block-tile-size",
841 "size of tiles for loop blocking.",
844 /* Maximal number of parameters that we allow in a SCoP. */
846 DEFPARAM (PARAM_GRAPHITE_MAX_NB_SCOP_PARAMS,
847 "graphite-max-nb-scop-params",
848 "maximum number of parameters in a SCoP.",
851 /* Maximal number of basic blocks in the functions analyzed by Graphite. */
853 DEFPARAM (PARAM_GRAPHITE_MAX_BBS_PER_FUNCTION,
854 "graphite-max-bbs-per-function",
855 "maximum number of basic blocks per function to be analyzed by Graphite.",
858 /* Maximal number of array references in a scop. */
860 DEFPARAM (PARAM_GRAPHITE_MAX_ARRAYS_PER_SCOP,
861 "graphite-max-arrays-per-scop",
862 "maximum number of arrays per scop.",
865 /* Maximal number of basic blocks in the functions analyzed by Graphite. */
867 DEFPARAM (PARAM_GRAPHITE_MIN_LOOPS_PER_FUNCTION,
868 "graphite-min-loops-per-function",
869 "minimal number of loops per function to be analyzed by Graphite.",
872 DEFPARAM (PARAM_MAX_ISL_OPERATIONS,
873 "max-isl-operations",
874 "maximum number of isl operations, 0 means unlimited",
877 /* Avoid data dependence analysis on very large loops. */
878 DEFPARAM (PARAM_LOOP_MAX_DATAREFS_FOR_DATADEPS,
879 "loop-max-datarefs-for-datadeps",
880 "Maximum number of datarefs in loop for building loop data dependencies.",
883 /* Avoid doing loop invariant motion on very large loops. */
885 DEFPARAM (PARAM_LOOP_INVARIANT_MAX_BBS_IN_LOOP,
886 "loop-invariant-max-bbs-in-loop",
887 "Max basic blocks number in loop for loop invariant motion.",
890 /* When the parameter is 1, use the internal function id
891 to look up for profile data. Otherwise, use a more stable
892 external id based on assembler name and source location. */
893 DEFPARAM (PARAM_PROFILE_FUNC_INTERNAL_ID,
894 "profile-func-internal-id",
895 "use internal function id in profile lookup.",
898 /* When the parameter is 1, track the most frequent N target
899 addresses in indirect-call profile. This disables
900 indirect_call_profiler_v2 which tracks single target. */
901 DEFPARAM (PARAM_INDIR_CALL_TOPN_PROFILE,
902 "indir-call-topn-profile",
903 "track topn target addresses in indirect-call profile.",
906 /* Avoid SLP vectorization of large basic blocks. */
907 DEFPARAM (PARAM_SLP_MAX_INSNS_IN_BB,
908 "slp-max-insns-in-bb",
909 "Maximum number of instructions in basic block to be considered for SLP vectorization.",
912 DEFPARAM (PARAM_MIN_INSN_TO_PREFETCH_RATIO,
913 "min-insn-to-prefetch-ratio",
914 "Min. ratio of insns to prefetches to enable prefetching for "
915 "a loop with an unknown trip count.",
918 DEFPARAM (PARAM_PREFETCH_MIN_INSN_TO_MEM_RATIO,
919 "prefetch-min-insn-to-mem-ratio",
920 "Min. ratio of insns to mem ops to enable prefetching in a loop.",
923 /* Set maximum hash table size for var tracking. */
925 DEFPARAM (PARAM_MAX_VARTRACK_SIZE,
927 "Max. size of var tracking hash tables.",
930 /* Set maximum recursion depth for var tracking expression expansion
933 DEFPARAM (PARAM_MAX_VARTRACK_EXPR_DEPTH,
934 "max-vartrack-expr-depth",
935 "Max. recursion depth for expanding var tracking expressions.",
938 /* Set maximum length of value location list for which var tracking
939 should add reverse operations. */
941 DEFPARAM (PARAM_MAX_VARTRACK_REVERSE_OP_SIZE,
942 "max-vartrack-reverse-op-size",
943 "Max. size of loc list for which reverse ops should be added.",
946 /* Set minimum insn uid for non-debug insns. */
948 DEFPARAM (PARAM_MIN_NONDEBUG_INSN_UID,
949 "min-nondebug-insn-uid",
950 "The minimum UID to be used for a nondebug insn.",
953 DEFPARAM (PARAM_IPA_SRA_PTR_GROWTH_FACTOR,
954 "ipa-sra-ptr-growth-factor",
955 "Maximum allowed growth of size of new parameters ipa-sra replaces "
956 "a pointer to an aggregate with.",
959 DEFPARAM (PARAM_TM_MAX_AGGREGATE_SIZE,
960 "tm-max-aggregate-size",
961 "Size in bytes after which thread-local aggregates should be "
962 "instrumented with the logging functions instead of save/restore "
966 DEFPARAM (PARAM_SRA_MAX_SCALARIZATION_SIZE_SPEED,
967 "sra-max-scalarization-size-Ospeed",
968 "Maximum size, in storage units, of an aggregate which should be "
969 "considered for scalarization when compiling for speed.",
972 DEFPARAM (PARAM_SRA_MAX_SCALARIZATION_SIZE_SIZE,
973 "sra-max-scalarization-size-Osize",
974 "Maximum size, in storage units, of an aggregate which should be "
975 "considered for scalarization when compiling for size.",
978 DEFPARAM (PARAM_IPA_CP_VALUE_LIST_SIZE,
979 "ipa-cp-value-list-size",
980 "Maximum size of a list of values associated with each parameter for "
981 "interprocedural constant propagation.",
984 DEFPARAM (PARAM_IPA_CP_EVAL_THRESHOLD,
985 "ipa-cp-eval-threshold",
986 "Threshold ipa-cp opportunity evaluation that is still considered "
987 "beneficial to clone..",
990 DEFPARAM (PARAM_IPA_CP_RECURSION_PENALTY,
991 "ipa-cp-recursion-penalty",
992 "Percentage penalty the recursive functions will receive when they "
993 "are evaluated for cloning..",
996 DEFPARAM (PARAM_IPA_CP_SINGLE_CALL_PENALTY,
997 "ipa-cp-single-call-penalty",
998 "Percentage penalty functions containg a single call to another "
999 "function will receive when they are evaluated for cloning..",
1002 DEFPARAM (PARAM_IPA_MAX_AGG_ITEMS,
1003 "ipa-max-agg-items",
1004 "Maximum number of aggregate content items for a parameter in "
1005 "jump functions and lattices.",
1008 DEFPARAM (PARAM_IPA_CP_LOOP_HINT_BONUS,
1009 "ipa-cp-loop-hint-bonus",
1010 "Compile-time bonus IPA-CP assigns to candidates which make loop "
1011 "bounds or strides known..",
1014 DEFPARAM (PARAM_IPA_CP_ARRAY_INDEX_HINT_BONUS,
1015 "ipa-cp-array-index-hint-bonus",
1016 "Compile-time bonus IPA-CP assigns to candidates which make an array "
1020 DEFPARAM (PARAM_IPA_MAX_AA_STEPS,
1022 "Maximum number of statements that will be visited by IPA formal "
1023 "parameter analysis based on alias analysis in any given function.",
1026 /* WHOPR partitioning configuration. */
1028 DEFPARAM (PARAM_LTO_PARTITIONS,
1030 "Number of partitions the program should be split to.",
1033 DEFPARAM (MIN_PARTITION_SIZE,
1034 "lto-min-partition",
1035 "Minimal size of a partition for LTO (in estimated instructions).",
1038 DEFPARAM (MAX_PARTITION_SIZE,
1039 "lto-max-partition",
1040 "Maximal size of a partition for LTO (in estimated instructions).",
1041 1000000, 0, INT_MAX)
1043 /* Diagnostic parameters. */
1045 DEFPARAM (CXX_MAX_NAMESPACES_FOR_DIAGNOSTIC_HELP,
1046 "cxx-max-namespaces-for-diagnostic-help",
1047 "Maximum number of namespaces to search for alternatives when "
1048 "name lookup fails.",
1051 /* Maximum number of conditional store pairs that can be sunk. */
1052 DEFPARAM (PARAM_MAX_STORES_TO_SINK,
1053 "max-stores-to-sink",
1054 "Maximum number of conditional store pairs that can be sunk.",
1057 /* Override CASE_VALUES_THRESHOLD of when to switch from doing switch
1058 statements via if statements to using a table jump operation. If the value
1059 is 0, the default CASE_VALUES_THRESHOLD will be used. */
1060 DEFPARAM (PARAM_CASE_VALUES_THRESHOLD,
1061 "case-values-threshold",
1062 "The smallest number of different values for which it is best to "
1063 "use a jump-table instead of a tree of conditional branches, "
1064 "if 0, use the default for the machine.",
1067 /* Data race flags for C++0x memory model compliance. */
1068 DEFPARAM (PARAM_ALLOW_STORE_DATA_RACES,
1069 "allow-store-data-races",
1070 "Allow new data races on stores to be introduced.",
1073 /* Reassociation width to be used by tree reassoc optimization. */
1074 DEFPARAM (PARAM_TREE_REASSOC_WIDTH,
1075 "tree-reassoc-width",
1076 "Set the maximum number of instructions executed in parallel in "
1077 "reassociated tree. If 0, use the target dependent heuristic..",
1080 DEFPARAM (PARAM_MAX_TAIL_MERGE_COMPARISONS,
1081 "max-tail-merge-comparisons",
1082 "Maximum amount of similar bbs to compare a bb with.",
1085 DEFPARAM (PARAM_MAX_TAIL_MERGE_ITERATIONS,
1086 "max-tail-merge-iterations",
1087 "Maximum amount of iterations of the pass over a function.",
1090 /* Maximum number of strings for which strlen optimization pass will
1091 track string lenths. */
1092 DEFPARAM (PARAM_MAX_TRACKED_STRLENS,
1093 "max-tracked-strlens",
1094 "Maximum number of strings for which strlen optimization pass will "
1095 "track string lengths.",
1098 /* Keep this in sync with the sched_pressure_algorithm enum. */
1099 DEFPARAM (PARAM_SCHED_PRESSURE_ALGORITHM,
1100 "sched-pressure-algorithm",
1101 "Which -fsched-pressure algorithm to apply.",
1104 /* Maximum length of candidate scans in straight-line strength reduction. */
1105 DEFPARAM (PARAM_MAX_SLSR_CANDIDATE_SCAN,
1106 "max-slsr-cand-scan",
1107 "Maximum length of candidate scans for straight-line "
1108 "strength reduction.",
1111 DEFPARAM (PARAM_ASAN_STACK,
1113 "Enable asan stack protection.",
1116 DEFPARAM (PARAM_ASAN_GLOBALS,
1118 "Enable asan globals protection.",
1121 DEFPARAM (PARAM_ASAN_INSTRUMENT_WRITES,
1122 "asan-instrument-writes",
1123 "Enable asan store operations protection.",
1126 DEFPARAM (PARAM_ASAN_INSTRUMENT_READS,
1127 "asan-instrument-reads",
1128 "Enable asan load operations protection.",
1131 DEFPARAM (PARAM_ASAN_MEMINTRIN,
1133 "Enable asan builtin functions protection.",
1136 DEFPARAM (PARAM_ASAN_USE_AFTER_RETURN,
1137 "asan-use-after-return",
1138 "Enable asan detection of use-after-return bugs.",
1141 DEFPARAM (PARAM_ASAN_INSTRUMENTATION_WITH_CALL_THRESHOLD,
1142 "asan-instrumentation-with-call-threshold",
1143 "Use callbacks instead of inline code if number of accesses "
1144 "in function becomes greater or equal to this number.",
1147 DEFPARAM (PARAM_UNINIT_CONTROL_DEP_ATTEMPTS,
1148 "uninit-control-dep-attempts",
1149 "Maximum number of nested calls to search for control dependencies "
1150 "during uninitialized variable analysis.",
1153 DEFPARAM (PARAM_CHKP_MAX_CTOR_SIZE,
1154 "chkp-max-ctor-size",
1155 "Maximum number of statements to be included into a single static "
1156 "constructor generated by Pointer Bounds Checker.",
1159 DEFPARAM (PARAM_FSM_SCALE_PATH_STMTS,
1160 "fsm-scale-path-stmts",
1161 "Scale factor to apply to the number of statements in a threading path when comparing to the number of (scaled) blocks.",
1164 DEFPARAM (PARAM_FSM_MAXIMUM_PHI_ARGUMENTS,
1165 "fsm-maximum-phi-arguments",
1166 "Maximum number of arguments a PHI may have before the FSM threader will not try to thread through its block.",
1169 DEFPARAM (PARAM_FSM_SCALE_PATH_BLOCKS,
1170 "fsm-scale-path-blocks",
1171 "Scale factor to apply to the number of blocks in a threading path when comparing to the number of (scaled) statements.",
1174 DEFPARAM (PARAM_MAX_FSM_THREAD_PATH_INSNS,
1175 "max-fsm-thread-path-insns",
1176 "Maximum number of instructions to copy when duplicating blocks on a finite state automaton jump thread path.",
1179 DEFPARAM (PARAM_MAX_FSM_THREAD_LENGTH,
1180 "max-fsm-thread-length",
1181 "Maximum number of basic blocks on a finite state automaton jump thread path.",
1184 DEFPARAM (PARAM_MAX_FSM_THREAD_PATHS,
1185 "max-fsm-thread-paths",
1186 "Maximum number of new jump thread paths to create for a finite state automaton.",
1189 DEFPARAM (PARAM_PARLOOPS_CHUNK_SIZE,
1190 "parloops-chunk-size",
1191 "Chunk size of omp schedule for loops parallelized by parloops.",
1194 DEFPARAMENUM5 (PARAM_PARLOOPS_SCHEDULE,
1195 "parloops-schedule",
1196 "Schedule type of omp schedule for loops parallelized by "
1197 "parloops (static, dynamic, guided, auto, runtime).",
1199 static, dynamic, guided, auto, runtime)
1201 DEFPARAM (PARAM_MAX_SSA_NAME_QUERY_DEPTH,
1202 "max-ssa-name-query-depth",
1203 "Maximum recursion depth allowed when querying a property of an"
1207 DEFPARAM (PARAM_MAX_RTL_IF_CONVERSION_INSNS,
1208 "max-rtl-if-conversion-insns",
1209 "Maximum number of insns in a basic block to consider for RTL "
1213 DEFPARAM (PARAM_HSA_GEN_DEBUG_STORES,
1214 "hsa-gen-debug-stores",
1215 "Level of hsa debug stores verbosity",
1218 DEFPARAM (PARAM_MAX_SPECULATIVE_DEVIRT_MAYDEFS,
1219 "max-speculative-devirt-maydefs",
1220 "Maximum number of may-defs visited when devirtualizing "
1221 "speculatively", 50, 0, 0)