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c6d9a88c 1/* params.def - Run-time parameters.
c75c517d 2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
3d8864c0 3 Free Software Foundation, Inc.
c6d9a88c
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4 Written by Mark Mitchell <mark@codesourcery.com>.
5
1322177d 6This file is part of GCC.
c6d9a88c 7
1322177d
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8GCC is free software; you can redistribute it and/or modify it under
9the terms of the GNU General Public License as published by the Free
9dcd6f09 10Software Foundation; either version 3, or (at your option) any later
1322177d 11version.
c6d9a88c 12
1322177d
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13GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14WARRANTY; without even the implied warranty of MERCHANTABILITY or
15FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16for more details.
c6d9a88c
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17
18You should have received a copy of the GNU General Public License
9dcd6f09
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19along with GCC; see the file COPYING3. If not see
20<http://www.gnu.org/licenses/>. */
c6d9a88c
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21
22/* This file contains definitions for language-independent
1eb68dca 23 parameters. The DEFPARAM macro takes 6 arguments:
c6d9a88c 24
0443f602 25 - The enumeral corresponding to this parameter.
c6d9a88c 26
b8698a0f 27 - The name that can be used to set this parameter using the
c6d9a88c
MM
28 command-line option `--param <name>=<value>'.
29
30 - A help string explaining how the parameter is used.
31
1c4c47db
JO
32 - A default value for the parameter.
33
9e7705cb 34 - The minimum acceptable value for the parameter.
1eb68dca 35
9e7705cb 36 - The maximum acceptable value for the parameter (if greater than
1eb68dca
KZ
37 the minimum).
38
1c4c47db 39 Be sure to add an entry to invoke.texi summarizing the parameter. */
c6d9a88c 40
ea429753 41/* The threshold ratio between current and hottest structure counts.
b8698a0f
L
42 We say that if the ratio of the current structure count,
43 calculated by profiling, to the hottest structure count
e1dc98b2
OG
44 in the program is less than this parameter, then structure
45 reorganization is not applied. The default is 10%. */
46DEFPARAM (PARAM_STRUCT_REORG_COLD_STRUCT_RATIO,
47 "struct-reorg-cold-struct-ratio",
ea429753 48 "The threshold ratio between current and hottest structure counts",
e1dc98b2
OG
49 10, 0, 100)
50
3a4fd356
JH
51/* When branch is predicted to be taken with probability lower than this
52 threshold (in percent), then it is considered well predictable. */
53DEFPARAM (PARAM_PREDICTABLE_BRANCH_OUTCOME,
54 "predictable-branch-outcome",
67018619 55 "Maximal estimated outcome of branch considered predictable",
3a4fd356
JH
56 2, 0, 50)
57
a6227154
KG
58/* The single function inlining limit. This is the maximum size
59 of a function counted in internal gcc instructions (not in
60 real machine instructions) that is eligible for inlining
61 by the tree inliner.
e5c4f28a 62 The default value is 450.
a6227154 63 Only functions marked inline (or methods defined in the class
e5c4f28a 64 definition for C++) are affected by this.
a6227154
KG
65 There are more restrictions to inlining: If inlined functions
66 call other functions, the already inlined instructions are
b8698a0f 67 counted and once the recursive inline limit (see
a6227154
KG
68 "max-inline-insns" parameter) is exceeded, the acceptable size
69 gets decreased. */
70DEFPARAM (PARAM_MAX_INLINE_INSNS_SINGLE,
71 "max-inline-insns-single",
bc522472 72 "The maximum number of instructions in a single function eligible for inlining",
172d54e0 73 400, 0, 0)
a6227154 74
bc522472
KG
75/* The single function inlining limit for functions that are
76 inlined by virtue of -finline-functions (-O3).
77 This limit should be chosen to be below or equal to the limit
78 that is applied to functions marked inlined (or defined in the
79 class declaration in C++) given by the "max-inline-insns-single"
80 parameter.
7802ca7c 81 The default value is 40. */
bc522472
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82DEFPARAM (PARAM_MAX_INLINE_INSNS_AUTO,
83 "max-inline-insns-auto",
84 "The maximum number of instructions when automatically inlining",
7802ca7c 85 40, 0, 0)
bc522472 86
6de9cd9a
DN
87DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE,
88 "max-inline-insns-recursive",
89 "The maximum number of instructions inline function can grow to via recursive inlining",
172d54e0 90 450, 0, 0)
6de9cd9a
DN
91
92DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO,
93 "max-inline-insns-recursive-auto",
94 "The maximum number of instructions non-inline function can grow to via recursive inlining",
172d54e0 95 450, 0, 0)
6de9cd9a
DN
96
97DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH,
98 "max-inline-recursive-depth",
99 "The maximum depth of recursive inlining for inline functions",
e06c0feb 100 8, 0, 0)
6de9cd9a
DN
101
102DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO,
103 "max-inline-recursive-depth-auto",
104 "The maximum depth of recursive inlining for non-inline functions",
e06c0feb 105 8, 0, 0)
6de9cd9a 106
c5a4444c
JH
107DEFPARAM (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY,
108 "min-inline-recursive-probability",
109 "Inline recursively only when the probability of call being executed exceeds the parameter",
110 10, 0, 0)
111
796bda22
JH
112/* Limit of iterations of early inliner. This basically bounds number of
113 nested indirect calls early inliner can resolve. Deeper chains are still
114 handled by late inlining. */
115DEFPARAM (PARAM_EARLY_INLINER_MAX_ITERATIONS,
116 "max-early-inliner-iterations",
117 "The maximum number of nested indirect inlining performed by early inliner",
118 10, 0, 0)
119
c5d0600d
JH
120/* Limit on probability of entry BB. */
121DEFPARAM (PARAM_COMDAT_SHARING_PROBABILITY,
122 "comdat-sharing-probability",
123 "Probability that COMDAT function will be shared with different compilatoin unit",
124 20, 0, 0)
125
3e485f62
JH
126/* Limit on probability of entry BB. */
127DEFPARAM (PARAM_PARTIAL_INLINING_ENTRY_PROBABILITY,
128 "partial-inlining-entry-probability",
129 "Maximum probability of the entry BB of split region (in percent relative to entry BB of the function) to make partial inlining happen",
130 70, 0, 0)
131
f37a4f14
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132/* Limit the number of expansions created by the variable expansion
133 optimization to avoid register pressure. */
134DEFPARAM (PARAM_MAX_VARIABLE_EXPANSIONS,
135 "max-variable-expansions-in-unroller",
5fa534e3 136 "If -fvariable-expansion-in-unroller is used, the maximum number of times that an individual variable will be expanded during loop unrolling",
e06c0feb 137 1, 0, 0)
b8698a0f 138
acdc40df
DN
139/* Limit loop autovectorization to loops with large enough iteration count. */
140DEFPARAM (PARAM_MIN_VECT_LOOP_BOUND,
141 "min-vect-loop-bound",
142 "If -ftree-vectorize is used, the minimal loop bound of a loop to be considered for vectorization",
8d888559 143 1, 1, 0)
acdc40df 144
0443f602
JO
145/* The maximum number of instructions to consider when looking for an
146 instruction to fill a delay slot. If more than this arbitrary
147 number of instructions is searched, the time savings from filling
148 the delay slot will be minimal so stop searching. Increasing
149 values mean more aggressive optimization, making the compile time
150 increase with probably small improvement in executable run time. */
151DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH,
152 "max-delay-slot-insn-search",
153 "The maximum number of instructions to consider to fill a delay slot",
e06c0feb 154 100, 0, 0)
0443f602 155
d5d063d7
JO
156/* When trying to fill delay slots, the maximum number of instructions
157 to consider when searching for a block with valid live register
158 information. Increasing this arbitrarily chosen value means more
159 aggressive optimization, increasing the compile time. This
160 parameter should be removed when the delay slot code is rewritten
161 to maintain the control-flow graph. */
162DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH,
163 "max-delay-slot-live-search",
164 "The maximum number of instructions to consider to find accurate live register information",
e06c0feb 165 333, 0, 0)
d5d063d7 166
b8698a0f 167/* This parameter limits the number of branch elements that the
ff7cc307 168 scheduler will track anti-dependencies through without resetting
b8698a0f
L
169 the tracking mechanism. Large functions with few calls or barriers
170 can generate lists containing many 1000's of dependencies. Generally
4a121cc3
AM
171 the compiler either uses all available memory, or runs for far too long. */
172DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH,
173 "max-pending-list-length",
174 "The maximum length of scheduling's pending operations list",
e06c0feb 175 32, 0, 0)
4a121cc3 176
b58b1157
JH
177DEFPARAM(PARAM_LARGE_FUNCTION_INSNS,
178 "large-function-insns",
179 "The size of function body to be considered large",
e5c4f28a 180 2700, 0, 0)
b58b1157
JH
181DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH,
182 "large-function-growth",
2cc98056 183 "Maximal growth due to inlining of large function (in percent)",
e06c0feb 184 100, 0, 0)
b4f32d07
JH
185DEFPARAM(PARAM_LARGE_UNIT_INSNS,
186 "large-unit-insns",
187 "The size of translation unit to be considered large",
188 10000, 0, 0)
b58b1157
JH
189DEFPARAM(PARAM_INLINE_UNIT_GROWTH,
190 "inline-unit-growth",
7b98c16f 191 "How much can given compilation unit grow because of the inlining (in percent)",
d562c668 192 30, 0, 0)
5e45130d
JH
193DEFPARAM(PARAM_IPCP_UNIT_GROWTH,
194 "ipcp-unit-growth",
7b98c16f 195 "How much can given compilation unit grow because of the interprocedural constant propagation (in percent)",
5e45130d 196 10, 0, 0)
85057983
JH
197DEFPARAM(PARAM_EARLY_INLINING_INSNS,
198 "early-inlining-insns",
7b98c16f 199 "Maximal estimated growth of function body caused by early inlining of single call",
211ceaca 200 10, 0, 0)
ff28a94d
JH
201DEFPARAM(PARAM_LARGE_STACK_FRAME,
202 "large-stack-frame",
203 "The size of stack frame to be considered large",
204 256, 0, 0)
205DEFPARAM(PARAM_STACK_FRAME_GROWTH,
206 "large-stack-frame-growth",
207 "Maximal stack frame growth due to inlining (in percent)",
208 1000, 0, 0)
b58b1157 209
f1fa37ff
MM
210/* The GCSE optimization will be disabled if it would require
211 significantly more memory than this value. */
212DEFPARAM(PARAM_MAX_GCSE_MEMORY,
213 "max-gcse-memory",
214 "The maximum amount of memory to be allocated by GCSE",
e06c0feb 215 50 * 1024 * 1024, 0, 0)
3906a4a1 216
f9957958
MH
217/* This is the threshold ratio when to perform partial redundancy
218 elimination after reload. We perform partial redundancy elimination
219 when the following holds:
220 (Redundant load execution count)
221 ------------------------------- >= GCSE_AFTER_RELOAD_PARTIAL_FRACTION
222 (Added loads execution count) */
223DEFPARAM(PARAM_GCSE_AFTER_RELOAD_PARTIAL_FRACTION,
224 "gcse-after-reload-partial-fraction",
c85ce869 225 "The threshold ratio for performing partial redundancy elimination after reload",
e06c0feb 226 3, 0, 0)
f9957958
MH
227/* This is the threshold ratio of the critical edges execution count compared to
228 the redundant loads execution count that permits performing the load
229 redundancy elimination in gcse after reload. */
230DEFPARAM(PARAM_GCSE_AFTER_RELOAD_CRITICAL_FRACTION,
231 "gcse-after-reload-critical-fraction",
c85ce869 232 "The threshold ratio of critical edges execution count that permit performing redundancy elimination after reload",
e06c0feb 233 10, 0, 0)
20160347
MK
234
235/* GCSE will use GCSE_COST_DISTANCE_RATION as a scaling factor
236 to calculate maximum distance for which an expression is allowed to move
237 from its rtx_cost. */
238DEFPARAM(PARAM_GCSE_COST_DISTANCE_RATIO,
239 "gcse-cost-distance-ratio",
240 "Scaling factor in calculation of maximum distance an expression can be moved by GCSE optimizations",
241 10, 0, 0)
242/* GCSE won't restrict distance for which an expression with rtx_cost greater
243 than COSTS_N_INSN(GCSE_UNRESTRICTED_COST) is allowed to move. */
244DEFPARAM(PARAM_GCSE_UNRESTRICTED_COST,
245 "gcse-unrestricted-cost",
246 "Cost at which GCSE optimizations will not constraint the distance an expression can travel",
247 3, 0, 0)
248
cad9aa15
MK
249/* How deep from a given basic block the dominator tree should be searched
250 for expressions to hoist to the block. The value of 0 will avoid limiting
251 the search. */
252DEFPARAM(PARAM_MAX_HOIST_DEPTH,
253 "max-hoist-depth",
254 "Maximum depth of search in the dominator tree for expressions to hoist",
255 30, 0, 0)
256
03e9dbc9 257/* This parameter limits the number of insns in a loop that will be unrolled,
701ad47e 258 and by how much the loop is unrolled.
b8698a0f 259
701ad47e
JH
260 This limit should be at most half of the peeling limits: loop unroller
261 decides to not unroll loops that iterate fewer than 2*number of allowed
a1105617 262 unrollings and thus we would have loops that are neither peeled or unrolled
701ad47e 263 otherwise. */
03e9dbc9
MM
264DEFPARAM(PARAM_MAX_UNROLLED_INSNS,
265 "max-unrolled-insns",
266 "The maximum number of instructions to consider to unroll in a loop",
e06c0feb 267 200, 0, 0)
b17d5d7c
ZD
268/* This parameter limits how many times the loop is unrolled depending
269 on number of insns really executed in each iteration. */
270DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS,
271 "max-average-unrolled-insns",
272 "The maximum number of instructions to consider to unroll in a loop on average",
e06c0feb 273 80, 0, 0)
b17d5d7c
ZD
274/* The maximum number of unrollings of a single loop. */
275DEFPARAM(PARAM_MAX_UNROLL_TIMES,
276 "max-unroll-times",
277 "The maximum number of unrollings of a single loop",
e06c0feb 278 8, 0, 0)
b17d5d7c
ZD
279/* The maximum number of insns of a peeled loop. */
280DEFPARAM(PARAM_MAX_PEELED_INSNS,
281 "max-peeled-insns",
282 "The maximum number of insns of a peeled loop",
e06c0feb 283 400, 0, 0)
b17d5d7c
ZD
284/* The maximum number of peelings of a single loop. */
285DEFPARAM(PARAM_MAX_PEEL_TIMES,
286 "max-peel-times",
287 "The maximum number of peelings of a single loop",
e06c0feb 288 16, 0, 0)
b17d5d7c
ZD
289/* The maximum number of insns of a peeled loop. */
290DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS,
291 "max-completely-peeled-insns",
292 "The maximum number of insns of a completely peeled loop",
e06c0feb 293 400, 0, 0)
b17d5d7c
ZD
294/* The maximum number of peelings of a single loop that is peeled completely. */
295DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES,
296 "max-completely-peel-times",
297 "The maximum number of peelings of a single loop that is peeled completely",
e06c0feb 298 16, 0, 0)
b17d5d7c
ZD
299/* The maximum number of insns of a peeled loop that rolls only once. */
300DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS,
301 "max-once-peeled-insns",
302 "The maximum number of insns of a peeled loop that rolls only once",
e06c0feb 303 400, 0, 0)
30bc1dca
RG
304/* The maximum depth of a loop nest we completely peel. */
305DEFPARAM(PARAM_MAX_UNROLL_ITERATIONS,
306 "max-completely-peel-loop-nest-depth",
307 "The maximum depth of a loop nest we completely peel",
308 8, 0, 0)
194734e9 309
617b465c
ZD
310/* The maximum number of insns of an unswitched loop. */
311DEFPARAM(PARAM_MAX_UNSWITCH_INSNS,
312 "max-unswitch-insns",
313 "The maximum number of insns of an unswitched loop",
e06c0feb 314 50, 0, 0)
617b465c
ZD
315/* The maximum level of recursion in unswitch_single_loop. */
316DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL,
317 "max-unswitch-level",
318 "The maximum number of unswitchings in a single loop",
e06c0feb 319 3, 0, 0)
617b465c 320
e9eb809d
ZD
321/* The maximum number of iterations of a loop the brute force algorithm
322 for analysis of # of iterations of the loop tries to evaluate. */
323DEFPARAM(PARAM_MAX_ITERATIONS_TO_TRACK,
324 "max-iterations-to-track",
e06c0feb
NS
325 "Bound on the number of iterations the brute force # of iterations analysis algorithm evaluates",
326 1000, 0, 0)
45b9a14b
BS
327/* A cutoff to avoid costly computations of the number of iterations in
328 the doloop transformation. */
329DEFPARAM(PARAM_MAX_ITERATIONS_COMPUTATION_COST,
330 "max-iterations-computation-cost",
331 "Bound on the cost of an expression to compute the number of iterations",
332 10, 0, 0)
e9eb809d 333
e5626198
AZ
334/* This parameter is used to tune SMS MAX II calculations. */
335DEFPARAM(PARAM_SMS_MAX_II_FACTOR,
336 "sms-max-ii-factor",
e06c0feb
NS
337 "A factor for tuning the upper bound that swing modulo scheduler uses for scheduling a loop",
338 100, 0, 0)
e5626198
AZ
339DEFPARAM(PARAM_SMS_DFA_HISTORY,
340 "sms-dfa-history",
5fa534e3 341 "The number of cycles the swing modulo scheduler considers when checking conflicts using DFA",
e06c0feb 342 0, 0, 0)
e5626198
AZ
343DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD,
344 "sms-loop-average-count-threshold",
e06c0feb
NS
345 "A threshold on the average loop count considered by the swing modulo scheduler",
346 0, 0, 0)
e5626198 347
194734e9
JH
348DEFPARAM(HOT_BB_COUNT_FRACTION,
349 "hot-bb-count-fraction",
e06c0feb
NS
350 "Select fraction of the maximal count of repetitions of basic block in program given basic block needs to have to be considered hot",
351 10000, 0, 0)
194734e9
JH
352DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
353 "hot-bb-frequency-fraction",
e06c0feb
NS
354 "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot",
355 1000, 0, 0)
95b9a3a5 356
edbed3d3
JH
357DEFPARAM (PARAM_ALIGN_THRESHOLD,
358 "align-threshold",
359 "Select fraction of the maximal frequency of executions of basic block in function given basic block get alignment",
360 100, 0, 0)
361
362DEFPARAM (PARAM_ALIGN_LOOP_ITERATIONS,
363 "align-loop-iterations",
364 "Loops iterating at least selected number of iterations will get loop alignement.",
365 4, 0, 0)
366
95b9a3a5
JH
367/* For guessed profiles, the loops having unknown number of iterations
368 are predicted to iterate relatively few (10) times at average.
369 For functions containing one loop with large known number of iterations
370 and other loops having unbounded loops we would end up predicting all
c83eecad 371 the other loops cold that is not usually the case. So we need to artificially
b8698a0f 372 flatten the profile.
95b9a3a5 373
6416ae7f 374 We need to cut the maximal predicted iterations to large enough iterations
95b9a3a5
JH
375 so the loop appears important, but safely within HOT_BB_COUNT_FRACTION
376 range. */
377
378DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS,
379 "max-predicted-iterations",
380 "The maximum number of loop iterations we predict statically",
381 100, 0, 0)
5c856b23
JH
382DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
383 "tracer-dynamic-coverage-feedback",
e06c0feb
NS
384 "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available",
385 95, 0, 100)
5c856b23
JH
386DEFPARAM(TRACER_DYNAMIC_COVERAGE,
387 "tracer-dynamic-coverage",
e06c0feb
NS
388 "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available",
389 75, 0, 100)
5c856b23
JH
390DEFPARAM(TRACER_MAX_CODE_GROWTH,
391 "tracer-max-code-growth",
2cc98056 392 "Maximal code growth caused by tail duplication (in percent)",
e06c0feb 393 100, 0, 0)
5c856b23
JH
394DEFPARAM(TRACER_MIN_BRANCH_RATIO,
395 "tracer-min-branch-ratio",
e06c0feb
NS
396 "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent)",
397 10, 0, 100)
5c856b23
JH
398DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
399 "tracer-min-branch-probability-feedback",
e06c0feb
NS
400 "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available",
401 80, 0, 100)
5c856b23
JH
402DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
403 "tracer-min-branch-probability",
e06c0feb
NS
404 "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available",
405 50, 0, 100)
3788cc17 406
5f24e0dc
RH
407/* The maximum number of incoming edges to consider for crossjumping. */
408DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
409 "max-crossjump-edges",
410 "The maximum number of incoming edges to consider for crossjumping",
e06c0feb 411 100, 0, 0)
5f24e0dc 412
12183e0f
PH
413/* The minimum number of matching instructions to consider for crossjumping. */
414DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS,
415 "min-crossjump-insns",
416 "The minimum number of matching instructions to consider for crossjumping",
e06c0feb 417 5, 0, 0)
12183e0f 418
f935b9e0
DE
419/* The maximum number expansion factor when copying basic blocks. */
420DEFPARAM(PARAM_MAX_GROW_COPY_BB_INSNS,
421 "max-grow-copy-bb-insns",
422 "The maximum expansion factor when copying basic blocks",
423 8, 0, 0)
424
bbcb0c05
SB
425/* The maximum number of insns to duplicate when unfactoring computed gotos. */
426DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS,
427 "max-goto-duplication-insns",
428 "The maximum number of insns to duplicate when unfactoring computed gotos",
429 8, 0, 0)
430
9bf8cfbf
ZD
431/* The maximum length of path considered in cse. */
432DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
433 "max-cse-path-length",
2cc98056 434 "The maximum length of path considered in cse",
e06c0feb 435 10, 0, 0)
95b9a3a5 436DEFPARAM(PARAM_MAX_CSE_INSNS,
921b02cd 437 "max-cse-insns",
95b9a3a5
JH
438 "The maximum instructions CSE process before flushing",
439 1000, 0, 0)
9bf8cfbf 440
a7e5372d
ZD
441/* The cost of expression in loop invariant motion that is considered
442 expensive. */
443DEFPARAM(PARAM_LIM_EXPENSIVE,
444 "lim-expensive",
445 "The minimum cost of an expensive expression in the loop invariant motion",
e06c0feb 446 20, 0, 0)
a7e5372d 447
8b11a64c
ZD
448/* Bound on number of candidates for induction variables below that
449 all candidates are considered for each use in induction variable
450 optimizations. */
451
452DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND,
453 "iv-consider-all-candidates-bound",
454 "Bound on number of candidates below that all candidates are considered in iv optimizations",
e06c0feb 455 30, 0, 0)
8b11a64c
ZD
456
457/* The induction variable optimizations give up on loops that contain more
458 induction variable uses. */
459
460DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES,
461 "iv-max-considered-uses",
462 "Bound on number of iv uses in loop optimized in iv optimizations",
e06c0feb 463 250, 0, 0)
8b11a64c 464
36f5ada1
ZD
465/* If there are at most this number of ivs in the set, try removing unnecessary
466 ivs from the set always. */
467
468DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND,
469 "iv-always-prune-cand-set-bound",
470 "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization",
471 10, 0, 0)
472
2412d35c
SP
473DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE,
474 "scev-max-expr-size",
475 "Bound on size of expressions used in the scalar evolutions analyzer",
57fe3c87 476 100, 0, 0)
2412d35c 477
3d8864c0
SP
478DEFPARAM(PARAM_OMEGA_MAX_VARS,
479 "omega-max-vars",
480 "Bound on the number of variables in Omega constraint systems",
481 128, 0, 0)
482
483DEFPARAM(PARAM_OMEGA_MAX_GEQS,
484 "omega-max-geqs",
485 "Bound on the number of inequalities in Omega constraint systems",
486 256, 0, 0)
487
488DEFPARAM(PARAM_OMEGA_MAX_EQS,
489 "omega-max-eqs",
490 "Bound on the number of equalities in Omega constraint systems",
491 128, 0, 0)
492
493DEFPARAM(PARAM_OMEGA_MAX_WILD_CARDS,
494 "omega-max-wild-cards",
495 "Bound on the number of wild cards in Omega constraint systems",
496 18, 0, 0)
497
498DEFPARAM(PARAM_OMEGA_HASH_TABLE_SIZE,
499 "omega-hash-table-size",
500 "Bound on the size of the hash table in Omega constraint systems",
501 550, 0, 0)
502
503DEFPARAM(PARAM_OMEGA_MAX_KEYS,
504 "omega-max-keys",
505 "Bound on the number of keys in Omega constraint systems",
506 500, 0, 0)
507
508DEFPARAM(PARAM_OMEGA_ELIMINATE_REDUNDANT_CONSTRAINTS,
509 "omega-eliminate-redundant-constraints",
510 "When set to 1, use expensive methods to eliminate all redundant constraints",
511 0, 0, 1)
512
bc1edb77
VK
513DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIGNMENT_CHECKS,
514 "vect-max-version-for-alignment-checks",
515 "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alignment check",
c12cc930
KB
516 6, 0, 0)
517
bc1edb77
VK
518DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS,
519 "vect-max-version-for-alias-checks",
520 "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alias check",
521 10, 0, 0)
522
c65ecebc
JH
523DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS,
524 "max-cselib-memory-locations",
525 "The maximum memory locations recorded by cselib",
e06c0feb 526 500, 0, 0)
c65ecebc 527
3788cc17
ZW
528#ifdef ENABLE_GC_ALWAYS_COLLECT
529# define GGC_MIN_EXPAND_DEFAULT 0
737c38d1 530# define GGC_MIN_HEAPSIZE_DEFAULT 0
3788cc17
ZW
531#else
532# define GGC_MIN_EXPAND_DEFAULT 30
737c38d1 533# define GGC_MIN_HEAPSIZE_DEFAULT 4096
3788cc17
ZW
534#endif
535
536DEFPARAM(GGC_MIN_EXPAND,
537 "ggc-min-expand",
e06c0feb
NS
538 "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap",
539 GGC_MIN_EXPAND_DEFAULT, 0, 0)
3788cc17 540
3788cc17
ZW
541DEFPARAM(GGC_MIN_HEAPSIZE,
542 "ggc-min-heapsize",
2cc98056 543 "Minimum heap size before we start collecting garbage, in kilobytes",
e06c0feb 544 GGC_MIN_HEAPSIZE_DEFAULT, 0, 0)
737c38d1
GK
545
546#undef GGC_MIN_EXPAND_DEFAULT
547#undef GGC_MIN_HEAPSIZE_DEFAULT
3788cc17 548
0bcf8261
JH
549DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
550 "max-reload-search-insns",
551 "The maximum number of instructions to search backward when looking for equivalent reload",
e06c0feb 552 100, 0, 0)
0bcf8261 553
f72c6b56
DE
554DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS,
555 "max-sched-region-blocks",
556 "The maximum number of blocks in a region to be considered for interblock scheduling",
e06c0feb 557 10, 0, 0)
f72c6b56
DE
558
559DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS,
560 "max-sched-region-insns",
561 "The maximum number of insns in a region to be considered for interblock scheduling",
e06c0feb 562 100, 0, 0)
f72c6b56 563
e855c69d
AB
564DEFPARAM(PARAM_MAX_PIPELINE_REGION_BLOCKS,
565 "max-pipeline-region-blocks",
566 "The maximum number of blocks in a region to be considered for interblock scheduling",
567 15, 0, 0)
568
569DEFPARAM(PARAM_MAX_PIPELINE_REGION_INSNS,
570 "max-pipeline-region-insns",
571 "The maximum number of insns in a region to be considered for interblock scheduling",
572 200, 0, 0)
573
6f48c21a
PS
574DEFPARAM(PARAM_MIN_SPEC_PROB,
575 "min-spec-prob",
576 "The minimum probability of reaching a source block for interblock speculative scheduling",
577 40, 0, 0)
578
d08eefb9
MK
579DEFPARAM(PARAM_MAX_SCHED_EXTEND_REGIONS_ITERS,
580 "max-sched-extend-regions-iters",
581 "The maximum number of iterations through CFG to extend regions",
bb83aa4b 582 0, 0, 0)
d08eefb9 583
496d7bb0
MK
584DEFPARAM(PARAM_MAX_SCHED_INSN_CONFLICT_DELAY,
585 "max-sched-insn-conflict-delay",
586 "The maximum conflict delay for an insn to be considered for speculative motion",
587 3, 1, 10)
588
589DEFPARAM(PARAM_SCHED_SPEC_PROB_CUTOFF,
590 "sched-spec-prob-cutoff",
591 "The minimal probability of speculation success (in percents), so that speculative insn will be scheduled.",
592 40, 0, 100)
593
e855c69d
AB
594DEFPARAM(PARAM_SELSCHED_MAX_LOOKAHEAD,
595 "selsched-max-lookahead",
596 "The maximum size of the lookahead window of selective scheduling",
597 50, 0, 0)
598
599DEFPARAM(PARAM_SELSCHED_MAX_SCHED_TIMES,
600 "selsched-max-sched-times",
601 "Maximum number of times that an insn could be scheduled",
602 2, 0, 0)
603
604DEFPARAM(PARAM_SELSCHED_INSNS_TO_RENAME,
605 "selsched-insns-to-rename",
606 "Maximum number of instructions in the ready list that are considered eligible for renaming",
607 2, 0, 0)
608
609DEFPARAM (PARAM_SCHED_MEM_TRUE_DEP_COST,
610 "sched-mem-true-dep-cost",
611 "Minimal distance between possibly conflicting store and load",
612 1, 0, 0)
613
49c3b9a8
JJ
614DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
615 "max-last-value-rtl",
616 "The maximum number of RTL nodes that can be recorded as combiner's last value",
617 10000, 0, 0)
618
89b0433e
NS
619/* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
620 {signed,unsigned} integral types. This determines N.
621 Experimentation shows 256 to be a good value. */
622DEFPARAM (PARAM_INTEGER_SHARE_LIMIT,
623 "integer-share-limit",
624 "The upper bound for sharing integer constants",
e06c0feb 625 256, 2, 2)
89b0433e 626
84d65814
DN
627/* Incremental SSA updates for virtual operands may be very slow if
628 there is a large number of mappings to process. In those cases, it
629 is faster to rewrite the virtual symbols from scratch as if they
630 had been recently introduced. This heuristic cannot be applied to
631 SSA mappings for real SSA names, only symbols kept in FUD chains.
632
633 PARAM_MIN_VIRTUAL_MAPPINGS specifies the minimum number of virtual
634 mappings that should be registered to trigger the heuristic.
b8698a0f 635
84d65814
DN
636 PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO specifies the ratio between
637 mappings and symbols. If the number of virtual mappings is
638 PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO bigger than the number of
639 virtual symbols to be updated, then the updater switches to a full
640 update for those symbols. */
641DEFPARAM (PARAM_MIN_VIRTUAL_MAPPINGS,
642 "min-virtual-mappings",
643 "Minimum number of virtual mappings to consider switching to full virtual renames",
644 100, 0, 0)
645
646DEFPARAM (PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO,
647 "virtual-mappings-ratio",
648 "Ratio between virtual mappings and virtual symbols to do full virtual renames",
649 3, 0, 0)
650
7d69de61
RH
651DEFPARAM (PARAM_SSP_BUFFER_SIZE,
652 "ssp-buffer-size",
653 "The lower bound for a buffer to be considered for stack smashing protection",
654 8, 1, 0)
655
43f31be5
JL
656/* When we thread through a block we have to make copies of the
657 statements within the block. Clearly for large blocks the code
658 duplication is bad.
659
660 PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number
661 of statements and PHI nodes allowed in a block which is going to
662 be duplicated for thread jumping purposes.
663
664 Some simple analysis showed that more than 99% of the jump
665 threading opportunities are for blocks with less than 15
666 statements. So we can get the benefits of jump threading
667 without excessive code bloat for pathological cases with the
668 throttle set at 15 statements. */
669DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS,
670 "max-jump-thread-duplication-stmts",
671 "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps",
672 15, 0, 0)
98035a75
DB
673
674/* This is the maximum number of fields a variable may have before the pointer analysis machinery
b8698a0f 675 will stop trying to treat it in a field-sensitive manner.
98035a75
DB
676 There are programs out there with thousands of fields per structure, and handling them
677 field-sensitively is not worth the cost. */
678DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE,
679 "max-fields-for-field-sensitive",
680 "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable",
d9338cf0 681 0, 0, 0)
6f8dd94b
EB
682
683DEFPARAM(PARAM_MAX_SCHED_READY_INSNS,
684 "max-sched-ready-insns",
685 "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass",
686 100, 0, 0)
687
47eb5b32
ZD
688/* Prefetching and cache-optimizations related parameters. Default values are
689 usually set by machine description. */
690
691/* The number of insns executed before prefetch is completed. */
692
693DEFPARAM (PARAM_PREFETCH_LATENCY,
694 "prefetch-latency",
695 "The number of insns executed before prefetch is completed",
696 200, 0, 0)
697
698/* The number of prefetches that can run at the same time. */
699
700DEFPARAM (PARAM_SIMULTANEOUS_PREFETCHES,
701 "simultaneous-prefetches",
702 "The number of prefetches that can run at the same time",
703 3, 0, 0)
704
46cb0441 705/* The size of L1 cache in kB. */
47eb5b32
ZD
706
707DEFPARAM (PARAM_L1_CACHE_SIZE,
708 "l1-cache-size",
709 "The size of L1 cache",
46cb0441 710 64, 0, 0)
47eb5b32
ZD
711
712/* The size of L1 cache line in bytes. */
713
714DEFPARAM (PARAM_L1_CACHE_LINE_SIZE,
715 "l1-cache-line-size",
716 "The size of L1 cache line",
717 32, 0, 0)
718
46cb0441
ZD
719/* The size of L2 cache in kB. */
720
721DEFPARAM (PARAM_L2_CACHE_SIZE,
722 "l2-cache-size",
723 "The size of L2 cache",
724 512, 0, 0)
725
7313518b
DG
726/* Whether we should use canonical types rather than deep "structural"
727 type checking. Setting this value to 1 (the default) improves
728 compilation performance in the C++ and Objective-C++ front end;
729 this value should only be set to zero to work around bugs in the
730 canonical type system by disabling it. */
731
732DEFPARAM (PARAM_USE_CANONICAL_TYPES,
733 "use-canonical-types",
734 "Whether to use canonical types",
735 1, 0, 1)
f0ed4cfb
NC
736
737DEFPARAM (PARAM_MAX_PARTIAL_ANTIC_LENGTH,
738 "max-partial-antic-length",
739 "Maximum length of partial antic set when performing tree pre optimization",
740 100, 0, 0)
741
863d2a57
RG
742/* The following is used as a stop-gap limit for cases where really huge
743 SCCs blow up memory and compile-time use too much. If we hit this limit,
744 SCCVN and such FRE and PRE will be not done at all for the current
745 function. */
746
747DEFPARAM (PARAM_SCCVN_MAX_SCC_SIZE,
748 "sccvn-max-scc-size",
749 "Maximum size of a SCC before SCCVN stops processing a function",
750 10000, 10, 0)
751
058e97ec
VM
752DEFPARAM (PARAM_IRA_MAX_LOOPS_NUM,
753 "ira-max-loops-num",
7b98c16f 754 "Max loops number for regional RA",
30ea859e 755 100, 0, 0)
058e97ec 756
311aab06
VM
757DEFPARAM (PARAM_IRA_MAX_CONFLICT_TABLE_SIZE,
758 "ira-max-conflict-table-size",
7b98c16f 759 "Max size of conflict table in MB",
7cd06356 760 1000, 0, 0)
311aab06 761
1833192f
VM
762DEFPARAM (PARAM_IRA_LOOP_RESERVED_REGS,
763 "ira-loop-reserved-regs",
764 "The number of registers in each class kept unused by loop invariant motion",
765 2, 0, 0)
766
b6e99746
MJ
767/* Switch initialization conversion will refuse to create arrays that are
768 bigger than this parameter times the number of switch branches. */
769
770DEFPARAM (PARAM_SWITCH_CONVERSION_BRANCH_RATIO,
771 "switch-conversion-max-branch-ratio",
772 "The maximum ratio between array size and switch branches for "
773 "a switch conversion to take place",
774 8, 1, 0)
775
e797c5f2
SP
776/* Size of tiles when doing loop blocking. */
777
778DEFPARAM (PARAM_LOOP_BLOCK_TILE_SIZE,
779 "loop-block-tile-size",
780 "size of tiles for loop blocking",
781 51, 0, 0)
782
4e7dd376
SP
783/* Maximal number of parameters that we allow in a SCoP. */
784
785DEFPARAM (PARAM_GRAPHITE_MAX_NB_SCOP_PARAMS,
786 "graphite-max-nb-scop-params",
d97c90ae 787 "maximum number of parameters in a SCoP",
4e7dd376
SP
788 10, 0, 0)
789
b6bb0094
SP
790/* Maximal number of basic blocks in the functions analyzed by Graphite. */
791
792DEFPARAM (PARAM_GRAPHITE_MAX_BBS_PER_FUNCTION,
793 "graphite-max-bbs-per-function",
d97c90ae 794 "maximum number of basic blocks per function to be analyzed by Graphite",
b6bb0094
SP
795 100, 0, 0)
796
b1fb9f56
JJ
797/* Avoid doing loop invariant motion on very large loops. */
798
799DEFPARAM (PARAM_LOOP_INVARIANT_MAX_BBS_IN_LOOP,
800 "loop-invariant-max-bbs-in-loop",
7b98c16f 801 "Max basic blocks number in loop for loop invariant motion",
b1fb9f56
JJ
802 10000, 0, 0)
803
a70d6342
IR
804/* Avoid SLP vectorization of large basic blocks. */
805DEFPARAM (PARAM_SLP_MAX_INSNS_IN_BB,
806 "slp-max-insns-in-bb",
807 "Maximum number of instructions in basic block to be considered for SLP vectorization",
808 1000, 0, 0)
809
db34470d
GS
810DEFPARAM (PARAM_MIN_INSN_TO_PREFETCH_RATIO,
811 "min-insn-to-prefetch-ratio",
7b98c16f 812 "Min. ratio of insns to prefetches to enable prefetching for "
db34470d
GS
813 "a loop with an unknown trip count",
814 10, 0, 0)
815
816DEFPARAM (PARAM_PREFETCH_MIN_INSN_TO_MEM_RATIO,
817 "prefetch-min-insn-to-mem-ratio",
7b98c16f 818 "Min. ratio of insns to mem ops to enable prefetching in a loop",
db34470d
GS
819 3, 0, 0)
820
ec8c3978
JJ
821/* Set maximum hash table size for var tracking. */
822
823DEFPARAM (PARAM_MAX_VARTRACK_SIZE,
824 "max-vartrack-size",
825 "Max. size of var tracking hash tables",
826 50000000, 0, 0)
827
b5b8b0ac
AO
828/* Set minimum insn uid for non-debug insns. */
829
830DEFPARAM (PARAM_MIN_NONDEBUG_INSN_UID,
831 "min-nondebug-insn-uid",
832 "The minimum UID to be used for a nondebug insn",
833 0, 1, 0)
834
07ffa034
MJ
835DEFPARAM (PARAM_IPA_SRA_PTR_GROWTH_FACTOR,
836 "ipa-sra-ptr-growth-factor",
7b98c16f 837 "Maximum allowed growth of size of new parameters ipa-sra replaces "
07ffa034
MJ
838 "a pointer to an aggregate with",
839 2, 0, 0)
840
3949c4a7
MJ
841DEFPARAM (PARAM_DEVIRT_TYPE_LIST_SIZE,
842 "devirt-type-list-size",
843 "Maximum size of a type list associated with each parameter for "
844 "devirtualization",
845 8, 0, 0)
846
852e4bd2
JH
847/* WHOPR partitioning configuration. */
848
849DEFPARAM (PARAM_LTO_PARTITIONS,
850 "lto-partitions",
851 "Number of paritions program should be split to",
852 32, 0, 0)
853
854DEFPARAM (MIN_PARTITION_SIZE,
855 "lto-min-partition",
856 "Size of minimal paritition for WHOPR (in estimated instructions)",
857 1000, 0, 0)
501c95ff
NF
858
859/* Diagnostic parameters. */
860
861DEFPARAM (CXX_MAX_NAMESPACES_FOR_DIAGNOSTIC_HELP,
862 "cxx-max-namespaces-for-diagnostic-help",
863 "Maximum number of namespaces to search for alternatives when "
864 "name lookup fails",
865 1000, 0, 0)
866
c6d9a88c
MM
867/*
868Local variables:
869mode:c
f4b4a3e2
NC
870End:
871*/