1 /* params.def - Run-time parameters.
2 Copyright (C) 2001-2015 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 50 * 1024 * 1024, 0, 0)
223 /* The GCSE optimization of an expression will avoided if the ratio of
224 insertions to deletions is greater than this value. */
225 DEFPARAM(PARAM_MAX_GCSE_INSERTION_RATIO,
226 "max-gcse-insertion-ratio",
227 "The maximum ratio of insertions to deletions of expressions in GCSE.",
230 /* This is the threshold ratio when to perform partial redundancy
231 elimination after reload. We perform partial redundancy elimination
232 when the following holds:
233 (Redundant load execution count)
234 ------------------------------- >= GCSE_AFTER_RELOAD_PARTIAL_FRACTION
235 (Added loads execution count) */
236 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_PARTIAL_FRACTION,
237 "gcse-after-reload-partial-fraction",
238 "The threshold ratio for performing partial redundancy elimination after reload.",
240 /* This is the threshold ratio of the critical edges execution count compared to
241 the redundant loads execution count that permits performing the load
242 redundancy elimination in gcse after reload. */
243 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_CRITICAL_FRACTION,
244 "gcse-after-reload-critical-fraction",
245 "The threshold ratio of critical edges execution count that permit performing redundancy elimination after reload.",
248 /* GCSE will use GCSE_COST_DISTANCE_RATION as a scaling factor
249 to calculate maximum distance for which an expression is allowed to move
250 from its rtx_cost. */
251 DEFPARAM(PARAM_GCSE_COST_DISTANCE_RATIO,
252 "gcse-cost-distance-ratio",
253 "Scaling factor in calculation of maximum distance an expression can be moved by GCSE optimizations.",
255 /* GCSE won't restrict distance for which an expression with rtx_cost greater
256 than COSTS_N_INSN(GCSE_UNRESTRICTED_COST) is allowed to move. */
257 DEFPARAM(PARAM_GCSE_UNRESTRICTED_COST,
258 "gcse-unrestricted-cost",
259 "Cost at which GCSE optimizations will not constraint the distance an expression can travel.",
262 /* How deep from a given basic block the dominator tree should be searched
263 for expressions to hoist to the block. The value of 0 will avoid limiting
265 DEFPARAM(PARAM_MAX_HOIST_DEPTH,
267 "Maximum depth of search in the dominator tree for expressions to hoist.",
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_VECT_MAX_VERSION_FOR_ALIGNMENT_CHECKS,
534 "vect-max-version-for-alignment-checks",
535 "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alignment check.",
538 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS,
539 "vect-max-version-for-alias-checks",
540 "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alias check.",
543 DEFPARAM(PARAM_VECT_MAX_PEELING_FOR_ALIGNMENT,
544 "vect-max-peeling-for-alignment",
545 "Max number of loop peels to enhancement alignment of data references in a loop.",
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_SCHED_AUTOPREF_QUEUE_DEPTH,
650 "sched-autopref-queue-depth",
651 "Hardware autoprefetcher scheduler model control flag. Number of lookahead cycles the model looks into; at '0' only enable instruction sorting heuristic. Disabled by default.",
654 DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
655 "max-last-value-rtl",
656 "The maximum number of RTL nodes that can be recorded as combiner's last value.",
659 DEFPARAM(PARAM_MAX_COMBINE_INSNS,
661 "The maximum number of insns combine tries to combine.",
664 /* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
665 {signed,unsigned} integral types. This determines N.
666 Experimentation shows 251 to be a good value that generates the
667 least amount of garbage for allocating the TREE_VEC storage. */
668 DEFPARAM (PARAM_INTEGER_SHARE_LIMIT,
669 "integer-share-limit",
670 "The upper bound for sharing integer constants.",
673 DEFPARAM (PARAM_SSP_BUFFER_SIZE,
675 "The lower bound for a buffer to be considered for stack smashing protection.",
678 DEFPARAM (PARAM_MIN_SIZE_FOR_STACK_SHARING,
679 "min-size-for-stack-sharing",
680 "The minimum size of variables taking part in stack slot sharing "
681 "when not optimizing.",
684 /* When we thread through a block we have to make copies of the
685 statements within the block. Clearly for large blocks the code
688 PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number
689 of statements and PHI nodes allowed in a block which is going to
690 be duplicated for thread jumping purposes.
692 Some simple analysis showed that more than 99% of the jump
693 threading opportunities are for blocks with less than 15
694 statements. So we can get the benefits of jump threading
695 without excessive code bloat for pathological cases with the
696 throttle set at 15 statements. */
697 DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS,
698 "max-jump-thread-duplication-stmts",
699 "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps.",
702 /* This is the maximum number of fields a variable may have before the pointer analysis machinery
703 will stop trying to treat it in a field-sensitive manner.
704 There are programs out there with thousands of fields per structure, and handling them
705 field-sensitively is not worth the cost. */
706 DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE,
707 "max-fields-for-field-sensitive",
708 "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable.",
711 DEFPARAM(PARAM_MAX_SCHED_READY_INSNS,
712 "max-sched-ready-insns",
713 "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass.",
716 /* This is the maximum number of active local stores RTL DSE will consider. */
717 DEFPARAM (PARAM_MAX_DSE_ACTIVE_LOCAL_STORES,
718 "max-dse-active-local-stores",
719 "Maximum number of active local stores in RTL dead store elimination.",
722 /* Prefetching and cache-optimizations related parameters. Default values are
723 usually set by machine description. */
725 /* The number of insns executed before prefetch is completed. */
727 DEFPARAM (PARAM_PREFETCH_LATENCY,
729 "The number of insns executed before prefetch is completed.",
732 /* The number of prefetches that can run at the same time. */
734 DEFPARAM (PARAM_SIMULTANEOUS_PREFETCHES,
735 "simultaneous-prefetches",
736 "The number of prefetches that can run at the same time.",
739 /* The size of L1 cache in kB. */
741 DEFPARAM (PARAM_L1_CACHE_SIZE,
743 "The size of L1 cache.",
746 /* The size of L1 cache line in bytes. */
748 DEFPARAM (PARAM_L1_CACHE_LINE_SIZE,
749 "l1-cache-line-size",
750 "The size of L1 cache line.",
753 /* The size of L2 cache in kB. */
755 DEFPARAM (PARAM_L2_CACHE_SIZE,
757 "The size of L2 cache.",
760 /* Whether we should use canonical types rather than deep "structural"
761 type checking. Setting this value to 1 (the default) improves
762 compilation performance in the C++ and Objective-C++ front end;
763 this value should only be set to zero to work around bugs in the
764 canonical type system by disabling it. */
766 DEFPARAM (PARAM_USE_CANONICAL_TYPES,
767 "use-canonical-types",
768 "Whether to use canonical types.",
771 DEFPARAM (PARAM_MAX_PARTIAL_ANTIC_LENGTH,
772 "max-partial-antic-length",
773 "Maximum length of partial antic set when performing tree pre optimization.",
776 /* The following is used as a stop-gap limit for cases where really huge
777 SCCs blow up memory and compile-time use too much. If we hit this limit,
778 SCCVN and such FRE and PRE will be not done at all for the current
781 DEFPARAM (PARAM_SCCVN_MAX_SCC_SIZE,
782 "sccvn-max-scc-size",
783 "Maximum size of a SCC before SCCVN stops processing a function.",
786 /* The following is used as a stop-gap limit for cases where really huge
787 functions blow up compile-time use too much. It limits the number of
788 alias-queries we do for finding common subexpressions for memory loads and
789 stores. The number of alias-queries is otherwise limited by the number of
790 stores on paths to function entry. */
792 DEFPARAM (PARAM_SCCVN_MAX_ALIAS_QUERIES_PER_ACCESS,
793 "sccvn-max-alias-queries-per-access",
794 "Maximum number of disambiguations to perform per memory access.",
797 DEFPARAM (PARAM_IRA_MAX_LOOPS_NUM,
799 "Max loops number for regional RA.",
802 DEFPARAM (PARAM_IRA_MAX_CONFLICT_TABLE_SIZE,
803 "ira-max-conflict-table-size",
804 "Max size of conflict table in MB.",
807 DEFPARAM (PARAM_IRA_LOOP_RESERVED_REGS,
808 "ira-loop-reserved-regs",
809 "The number of registers in each class kept unused by loop invariant motion.",
812 DEFPARAM (PARAM_LRA_MAX_CONSIDERED_RELOAD_PSEUDOS,
813 "lra-max-considered-reload-pseudos",
814 "The max number of reload pseudos which are considered during spilling a non-reload pseudo.",
817 DEFPARAM (PARAM_LRA_INHERITANCE_EBB_PROBABILITY_CUTOFF,
818 "lra-inheritance-ebb-probability-cutoff",
819 "Minimal fall-through edge probability in percentage used to add BB to inheritance EBB in LRA.",
822 /* Switch initialization conversion will refuse to create arrays that are
823 bigger than this parameter times the number of switch branches. */
825 DEFPARAM (PARAM_SWITCH_CONVERSION_BRANCH_RATIO,
826 "switch-conversion-max-branch-ratio",
827 "The maximum ratio between array size and switch branches for "
828 "a switch conversion to take place.",
831 /* Size of tiles when doing loop blocking. */
833 DEFPARAM (PARAM_LOOP_BLOCK_TILE_SIZE,
834 "loop-block-tile-size",
835 "size of tiles for loop blocking.",
838 /* Maximal number of parameters that we allow in a SCoP. */
840 DEFPARAM (PARAM_GRAPHITE_MAX_NB_SCOP_PARAMS,
841 "graphite-max-nb-scop-params",
842 "maximum number of parameters in a SCoP.",
845 /* Maximal number of basic blocks in the functions analyzed by Graphite. */
847 DEFPARAM (PARAM_GRAPHITE_MAX_BBS_PER_FUNCTION,
848 "graphite-max-bbs-per-function",
849 "maximum number of basic blocks per function to be analyzed by Graphite.",
852 /* Maximal number of array references in a scop. */
854 DEFPARAM (PARAM_GRAPHITE_MAX_ARRAYS_PER_SCOP,
855 "graphite-max-arrays-per-scop",
856 "maximum number of arrays per scop.",
859 /* Maximal number of basic blocks in the functions analyzed by Graphite. */
861 DEFPARAM (PARAM_GRAPHITE_MIN_LOOPS_PER_FUNCTION,
862 "graphite-min-loops-per-function",
863 "minimal number of loops per function to be analyzed by Graphite.",
866 DEFPARAM (PARAM_MAX_ISL_OPERATIONS,
867 "max-isl-operations",
868 "maximum number of ISL operations, 0 means unlimited",
871 /* Avoid data dependence analysis on very large loops. */
872 DEFPARAM (PARAM_LOOP_MAX_DATAREFS_FOR_DATADEPS,
873 "loop-max-datarefs-for-datadeps",
874 "Maximum number of datarefs in loop for building loop data dependencies.",
877 /* Avoid doing loop invariant motion on very large loops. */
879 DEFPARAM (PARAM_LOOP_INVARIANT_MAX_BBS_IN_LOOP,
880 "loop-invariant-max-bbs-in-loop",
881 "Max basic blocks number in loop for loop invariant motion.",
884 /* When the parameter is 1, use the internal function id
885 to look up for profile data. Otherwise, use a more stable
886 external id based on assembler name and source location. */
887 DEFPARAM (PARAM_PROFILE_FUNC_INTERNAL_ID,
888 "profile-func-internal-id",
889 "use internal function id in profile lookup.",
892 /* When the parameter is 1, track the most frequent N target
893 addresses in indirect-call profile. This disables
894 indirect_call_profiler_v2 which tracks single target. */
895 DEFPARAM (PARAM_INDIR_CALL_TOPN_PROFILE,
896 "indir-call-topn-profile",
897 "track topn target addresses in indirect-call profile.",
900 /* Avoid SLP vectorization of large basic blocks. */
901 DEFPARAM (PARAM_SLP_MAX_INSNS_IN_BB,
902 "slp-max-insns-in-bb",
903 "Maximum number of instructions in basic block to be considered for SLP vectorization.",
906 DEFPARAM (PARAM_MIN_INSN_TO_PREFETCH_RATIO,
907 "min-insn-to-prefetch-ratio",
908 "Min. ratio of insns to prefetches to enable prefetching for "
909 "a loop with an unknown trip count.",
912 DEFPARAM (PARAM_PREFETCH_MIN_INSN_TO_MEM_RATIO,
913 "prefetch-min-insn-to-mem-ratio",
914 "Min. ratio of insns to mem ops to enable prefetching in a loop.",
917 /* Set maximum hash table size for var tracking. */
919 DEFPARAM (PARAM_MAX_VARTRACK_SIZE,
921 "Max. size of var tracking hash tables.",
924 /* Set maximum recursion depth for var tracking expression expansion
927 DEFPARAM (PARAM_MAX_VARTRACK_EXPR_DEPTH,
928 "max-vartrack-expr-depth",
929 "Max. recursion depth for expanding var tracking expressions.",
932 /* Set maximum length of value location list for which var tracking
933 should add reverse operations. */
935 DEFPARAM (PARAM_MAX_VARTRACK_REVERSE_OP_SIZE,
936 "max-vartrack-reverse-op-size",
937 "Max. size of loc list for which reverse ops should be added.",
940 /* Set minimum insn uid for non-debug insns. */
942 DEFPARAM (PARAM_MIN_NONDEBUG_INSN_UID,
943 "min-nondebug-insn-uid",
944 "The minimum UID to be used for a nondebug insn.",
947 DEFPARAM (PARAM_IPA_SRA_PTR_GROWTH_FACTOR,
948 "ipa-sra-ptr-growth-factor",
949 "Maximum allowed growth of size of new parameters ipa-sra replaces "
950 "a pointer to an aggregate with.",
953 DEFPARAM (PARAM_TM_MAX_AGGREGATE_SIZE,
954 "tm-max-aggregate-size",
955 "Size in bytes after which thread-local aggregates should be "
956 "instrumented with the logging functions instead of save/restore "
960 DEFPARAM (PARAM_SRA_MAX_SCALARIZATION_SIZE_SPEED,
961 "sra-max-scalarization-size-Ospeed",
962 "Maximum size, in storage units, of an aggregate which should be "
963 "considered for scalarization when compiling for speed.",
966 DEFPARAM (PARAM_SRA_MAX_SCALARIZATION_SIZE_SIZE,
967 "sra-max-scalarization-size-Osize",
968 "Maximum size, in storage units, of an aggregate which should be "
969 "considered for scalarization when compiling for size.",
972 DEFPARAM (PARAM_IPA_CP_VALUE_LIST_SIZE,
973 "ipa-cp-value-list-size",
974 "Maximum size of a list of values associated with each parameter for "
975 "interprocedural constant propagation.",
978 DEFPARAM (PARAM_IPA_CP_EVAL_THRESHOLD,
979 "ipa-cp-eval-threshold",
980 "Threshold ipa-cp opportunity evaluation that is still considered "
981 "beneficial to clone..",
984 DEFPARAM (PARAM_IPA_CP_RECURSION_PENALTY,
985 "ipa-cp-recursion-penalty",
986 "Percentage penalty the recursive functions will receive when they "
987 "are evaluated for cloning..",
990 DEFPARAM (PARAM_IPA_CP_SINGLE_CALL_PENALTY,
991 "ipa-cp-single-call-penalty",
992 "Percentage penalty functions containg a single call to another "
993 "function will receive when they are evaluated for cloning..",
996 DEFPARAM (PARAM_IPA_MAX_AGG_ITEMS,
998 "Maximum number of aggregate content items for a parameter in "
999 "jump functions and lattices.",
1002 DEFPARAM (PARAM_IPA_CP_LOOP_HINT_BONUS,
1003 "ipa-cp-loop-hint-bonus",
1004 "Compile-time bonus IPA-CP assigns to candidates which make loop "
1005 "bounds or strides known..",
1008 DEFPARAM (PARAM_IPA_CP_ARRAY_INDEX_HINT_BONUS,
1009 "ipa-cp-array-index-hint-bonus",
1010 "Compile-time bonus IPA-CP assigns to candidates which make an array "
1014 DEFPARAM (PARAM_IPA_MAX_AA_STEPS,
1016 "Maximum number of statements that will be visited by IPA formal "
1017 "parameter analysis based on alias analysis in any given function.",
1020 /* WHOPR partitioning configuration. */
1022 DEFPARAM (PARAM_LTO_PARTITIONS,
1024 "Number of partitions the program should be split to.",
1027 DEFPARAM (MIN_PARTITION_SIZE,
1028 "lto-min-partition",
1029 "Minimal size of a partition for LTO (in estimated instructions).",
1032 /* Diagnostic parameters. */
1034 DEFPARAM (CXX_MAX_NAMESPACES_FOR_DIAGNOSTIC_HELP,
1035 "cxx-max-namespaces-for-diagnostic-help",
1036 "Maximum number of namespaces to search for alternatives when "
1037 "name lookup fails.",
1040 /* Maximum number of conditional store pairs that can be sunk. */
1041 DEFPARAM (PARAM_MAX_STORES_TO_SINK,
1042 "max-stores-to-sink",
1043 "Maximum number of conditional store pairs that can be sunk.",
1046 /* Override CASE_VALUES_THRESHOLD of when to switch from doing switch
1047 statements via if statements to using a table jump operation. If the value
1048 is 0, the default CASE_VALUES_THRESHOLD will be used. */
1049 DEFPARAM (PARAM_CASE_VALUES_THRESHOLD,
1050 "case-values-threshold",
1051 "The smallest number of different values for which it is best to "
1052 "use a jump-table instead of a tree of conditional branches, "
1053 "if 0, use the default for the machine.",
1056 /* Data race flags for C++0x memory model compliance. */
1057 DEFPARAM (PARAM_ALLOW_STORE_DATA_RACES,
1058 "allow-store-data-races",
1059 "Allow new data races on stores to be introduced.",
1062 /* Reassociation width to be used by tree reassoc optimization. */
1063 DEFPARAM (PARAM_TREE_REASSOC_WIDTH,
1064 "tree-reassoc-width",
1065 "Set the maximum number of instructions executed in parallel in "
1066 "reassociated tree. If 0, use the target dependent heuristic..",
1069 DEFPARAM (PARAM_MAX_TAIL_MERGE_COMPARISONS,
1070 "max-tail-merge-comparisons",
1071 "Maximum amount of similar bbs to compare a bb with.",
1074 DEFPARAM (PARAM_MAX_TAIL_MERGE_ITERATIONS,
1075 "max-tail-merge-iterations",
1076 "Maximum amount of iterations of the pass over a function.",
1079 /* Maximum number of strings for which strlen optimization pass will
1080 track string lenths. */
1081 DEFPARAM (PARAM_MAX_TRACKED_STRLENS,
1082 "max-tracked-strlens",
1083 "Maximum number of strings for which strlen optimization pass will "
1084 "track string lengths.",
1087 /* Keep this in sync with the sched_pressure_algorithm enum. */
1088 DEFPARAM (PARAM_SCHED_PRESSURE_ALGORITHM,
1089 "sched-pressure-algorithm",
1090 "Which -fsched-pressure algorithm to apply.",
1093 /* Maximum length of candidate scans in straight-line strength reduction. */
1094 DEFPARAM (PARAM_MAX_SLSR_CANDIDATE_SCAN,
1095 "max-slsr-cand-scan",
1096 "Maximum length of candidate scans for straight-line "
1097 "strength reduction.",
1100 DEFPARAM (PARAM_ASAN_STACK,
1102 "Enable asan stack protection.",
1105 DEFPARAM (PARAM_ASAN_GLOBALS,
1107 "Enable asan globals protection.",
1110 DEFPARAM (PARAM_ASAN_INSTRUMENT_WRITES,
1111 "asan-instrument-writes",
1112 "Enable asan store operations protection.",
1115 DEFPARAM (PARAM_ASAN_INSTRUMENT_READS,
1116 "asan-instrument-reads",
1117 "Enable asan load operations protection.",
1120 DEFPARAM (PARAM_ASAN_MEMINTRIN,
1122 "Enable asan builtin functions protection.",
1125 DEFPARAM (PARAM_ASAN_USE_AFTER_RETURN,
1126 "asan-use-after-return",
1127 "Enable asan detection of use-after-return bugs.",
1130 DEFPARAM (PARAM_ASAN_INSTRUMENTATION_WITH_CALL_THRESHOLD,
1131 "asan-instrumentation-with-call-threshold",
1132 "Use callbacks instead of inline code if number of accesses "
1133 "in function becomes greater or equal to this number.",
1136 DEFPARAM (PARAM_UNINIT_CONTROL_DEP_ATTEMPTS,
1137 "uninit-control-dep-attempts",
1138 "Maximum number of nested calls to search for control dependencies "
1139 "during uninitialized variable analysis.",
1142 DEFPARAM (PARAM_CHKP_MAX_CTOR_SIZE,
1143 "chkp-max-ctor-size",
1144 "Maximum number of statements to be included into a single static "
1145 "constructor generated by Pointer Bounds Checker.",
1148 DEFPARAM (PARAM_MAX_FSM_THREAD_PATH_INSNS,
1149 "max-fsm-thread-path-insns",
1150 "Maximum number of instructions to copy when duplicating blocks on a finite state automaton jump thread path.",
1153 DEFPARAM (PARAM_MAX_FSM_THREAD_LENGTH,
1154 "max-fsm-thread-length",
1155 "Maximum number of basic blocks on a finite state automaton jump thread path.",
1158 DEFPARAM (PARAM_MAX_FSM_THREAD_PATHS,
1159 "max-fsm-thread-paths",
1160 "Maximum number of new jump thread paths to create for a finite state automaton.",
1163 DEFPARAM (PARAM_PARLOOPS_CHUNK_SIZE,
1164 "parloops-chunk-size",
1165 "Chunk size of omp schedule for loops parallelized by parloops.",
1168 DEFPARAMENUM5 (PARAM_PARLOOPS_SCHEDULE,
1169 "parloops-schedule",
1170 "Schedule type of omp schedule for loops parallelized by "
1171 "parloops (static, dynamic, guided, auto, runtime).",
1173 static, dynamic, guided, auto, runtime)
1175 DEFPARAM (PARAM_MAX_SSA_NAME_QUERY_DEPTH,
1176 "max-ssa-name-query-depth",
1177 "Maximum recursion depth allowed when querying a property of an"