1 /* params.def
- Run
-time parameters.
2 Copyright (C
) 2001, 2002, 2004 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
2, 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 COPYING. If not
, write to the Free
19 Software Foundation
, 59 Temple Place
- Suite
330, Boston
, MA
24 /* This file contains definitions for language
-independent
25 parameters. The DEFPARAM macro takes
4 arguments
:
27 - The enumeral corresponding to this parameter.
29 - The name that can be used to set this parameter using the
30 command
-line option `
--param
<name
>=<value
>'.
32 - A help string explaining how the parameter is used.
34 - A default value for the parameter.
36 Be sure to add an entry to invoke.texi summarizing the parameter. */
38 /* The single function inlining limit. This is the maximum size
39 of a function counted in internal gcc instructions (not in
40 real machine instructions) that is eligible for inlining
42 The default value is 500.
43 Only functions marked inline (or methods defined in the class
44 definition for C++) are affected by this, unless you set the
45 -finline-functions (included in -O3) compiler option.
46 There are more restrictions to inlining: If inlined functions
47 call other functions, the already inlined instructions are
48 counted and once the recursive inline limit (see
49 "max-inline-insns" parameter) is exceeded, the acceptable size
51 DEFPARAM (PARAM_MAX_INLINE_INSNS_SINGLE,
52 "max-inline-insns-single",
53 "The maximum number of instructions in a single function eligible for inlining",
56 /* The single function inlining limit for functions that are
57 inlined by virtue of -finline-functions (-O3).
58 This limit should be chosen to be below or equal to the limit
59 that is applied to functions marked inlined (or defined in the
60 class declaration in C++) given by the "max-inline-insns-single"
62 The default value is 150. */
63 DEFPARAM (PARAM_MAX_INLINE_INSNS_AUTO,
64 "max-inline-insns-auto",
65 "The maximum number of instructions when automatically inlining",
68 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE,
69 "max-inline-insns-recursive",
70 "The maximum number of instructions inline function can grow to via recursive inlining",
73 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO,
74 "max-inline-insns-recursive-auto",
75 "The maximum number of instructions non-inline function can grow to via recursive inlining",
78 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH,
79 "max-inline-recursive-depth",
80 "The maximum depth of recursive inlining for inline functions",
83 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO,
84 "max-inline-recursive-depth-auto",
85 "The maximum depth of recursive inlining for non-inline functions",
88 /* For languages that (still) use the RTL inliner, we can specify
89 limits for the RTL inliner separately.
90 The parameter here defines the maximum number of RTL instructions
91 a function may have to be eligible for inlining in the RTL inliner.
92 The default value is 600. */
93 DEFPARAM (PARAM_MAX_INLINE_INSNS_RTL,
94 "max-inline-insns-rtl",
95 "The maximum number of instructions for the RTL inliner",
98 /* Limit the number of expansions created by the variable expansion
99 optimization to avoid register pressure. */
100 DEFPARAM (PARAM_MAX_VARIABLE_EXPANSIONS,
101 "max-variable-expansions-in-unroller",
102 "If -fvariable-expansion-in-unroller is used, the maximum number of \
103 times that an individual variable will be expanded \
104 during loop unrolling",
107 /* The maximum number of instructions to consider when looking for an
108 instruction to fill a delay slot. If more than this arbitrary
109 number of instructions is searched, the time savings from filling
110 the delay slot will be minimal so stop searching. Increasing
111 values mean more aggressive optimization, making the compile time
112 increase with probably small improvement in executable run time. */
113 DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH,
114 "max-delay-slot-insn-search",
115 "The maximum number of instructions to consider to fill a delay slot",
118 /* When trying to fill delay slots, the maximum number of instructions
119 to consider when searching for a block with valid live register
120 information. Increasing this arbitrarily chosen value means more
121 aggressive optimization, increasing the compile time. This
122 parameter should be removed when the delay slot code is rewritten
123 to maintain the control-flow graph. */
124 DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH,
125 "max-delay-slot-live-search",
126 "The maximum number of instructions to consider to find accurate live register information",
129 /* This parameter limits the number of branch elements that the
130 scheduler will track anti-dependencies through without resetting
131 the tracking mechanism. Large functions with few calls or barriers
132 can generate lists containing many 1000's of dependencies. Generally
133 the compiler either uses all available memory
, or runs for far too long.
*/
134 DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH
,
135 "max-pending-list-length",
136 "The maximum length of scheduling's pending operations list",
139 DEFPARAM(PARAM_LARGE_FUNCTION_INSNS
,
140 "large-function-insns",
141 "The size of function body to be considered large",
143 DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH
,
144 "large-function-growth",
145 "Maximal growth due to inlining of large function (in percent)",
147 DEFPARAM(PARAM_INLINE_UNIT_GROWTH
,
148 "inline-unit-growth",
149 "how much can given compilation unit grow because of the inlining (in percent)",
152 /* The GCSE optimization will be disabled if it would require
153 significantly more memory than this value.
*/
154 DEFPARAM(PARAM_MAX_GCSE_MEMORY
,
156 "The maximum amount of memory to be allocated by GCSE",
158 /* The number of repetitions of copy
/const prop and PRE to run.
*/
159 DEFPARAM(PARAM_MAX_GCSE_PASSES
,
161 "The maximum number of passes to make when doing GCSE",
163 /* This is the threshold ratio when to perform partial redundancy
164 elimination after reload. We perform partial redundancy elimination
165 when the following holds
:
166 (Redundant load execution count
)
167 ------------------------------- >= GCSE_AFTER_RELOAD_PARTIAL_FRACTION
168 (Added loads execution count
) */
169 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_PARTIAL_FRACTION
,
170 "gcse-after-reload-partial-fraction",
171 "The threshold ratio for performing partial redundancy elimination \
174 /* This is the threshold ratio of the critical edges execution count compared to
175 the redundant loads execution count that permits performing the load
176 redundancy elimination in gcse after reload.
*/
177 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_CRITICAL_FRACTION
,
178 "gcse-after-reload-critical-fraction",
179 "The threshold ratio of critical edges execution count that permit \
180 performing redundancy elimination after reload.",
182 /* This parameter limits the number of insns in a loop that will be unrolled
,
183 and by how much the loop is unrolled.
185 This limit should be at most half of the peeling limits
: loop unroller
186 decides to not unroll loops that iterate fewer than
2*number of allowed
187 unrollings and thus we would have loops that are neither peeled or unrolled
189 DEFPARAM(PARAM_MAX_UNROLLED_INSNS
,
190 "max-unrolled-insns",
191 "The maximum number of instructions to consider to unroll in a loop",
193 /* This parameter limits how many times the loop is unrolled depending
194 on number of insns really executed in each iteration.
*/
195 DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS
,
196 "max-average-unrolled-insns",
197 "The maximum number of instructions to consider to unroll in a loop on average",
199 /* The maximum number of unrollings of a single loop.
*/
200 DEFPARAM(PARAM_MAX_UNROLL_TIMES
,
202 "The maximum number of unrollings of a single loop",
204 /* The maximum number of insns of a peeled loop.
*/
205 DEFPARAM(PARAM_MAX_PEELED_INSNS
,
207 "The maximum number of insns of a peeled loop",
209 /* The maximum number of peelings of a single loop.
*/
210 DEFPARAM(PARAM_MAX_PEEL_TIMES
,
212 "The maximum number of peelings of a single loop",
214 /* The maximum number of insns of a peeled loop.
*/
215 DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS
,
216 "max-completely-peeled-insns",
217 "The maximum number of insns of a completely peeled loop",
219 /* The maximum number of peelings of a single loop that is peeled completely.
*/
220 DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES
,
221 "max-completely-peel-times",
222 "The maximum number of peelings of a single loop that is peeled completely",
224 /* The maximum number of insns of a peeled loop that rolls only once.
*/
225 DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS
,
226 "max-once-peeled-insns",
227 "The maximum number of insns of a peeled loop that rolls only once",
230 /* The maximum number of insns of an unswitched loop.
*/
231 DEFPARAM(PARAM_MAX_UNSWITCH_INSNS
,
232 "max-unswitch-insns",
233 "The maximum number of insns of an unswitched loop",
235 /* The maximum level of recursion in unswitch_single_loop.
*/
236 DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL
,
237 "max-unswitch-level",
238 "The maximum number of unswitchings in a single loop",
241 /* The maximum number of iterations of a loop the brute force algorithm
242 for analysis of # of iterations of the loop tries to evaluate.
*/
243 DEFPARAM(PARAM_MAX_ITERATIONS_TO_TRACK
,
244 "max-iterations-to-track",
245 "Bound on the number of iterations the brute force # of iterations \
246 analysis algorithm evaluates",
249 DEFPARAM(PARAM_MAX_SMS_LOOP_NUMBER
,
250 "max-sms-loop-number",
251 "Maximum number of loops to perform swing modulo scheduling on \
252 (mainly for debugging)",
255 /* This parameter is used to tune SMS
MAX II calculations.
*/
256 DEFPARAM(PARAM_SMS_MAX_II_FACTOR
,
258 "A factor for tuning the upper bound that swing modulo scheduler uses \
259 for scheduling a loop",
261 DEFPARAM(PARAM_SMS_DFA_HISTORY
,
263 "The number of cycles the swing modulo scheduler considers when \
264 checking conflicts using DFA",
266 DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD
,
267 "sms-loop-average-count-threshold",
268 "A threshold on the average loop count considered by the swing modulo \
272 DEFPARAM(HOT_BB_COUNT_FRACTION
,
273 "hot-bb-count-fraction",
274 "Select fraction of the maximal count of repetitions of basic block in \
275 program given basic block needs to have to be considered hot",
277 DEFPARAM(HOT_BB_FREQUENCY_FRACTION
,
278 "hot-bb-frequency-fraction",
279 "Select fraction of the maximal frequency of executions of basic \
280 block in function given basic block needs to have to be considered hot",
282 DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK
,
283 "tracer-dynamic-coverage-feedback",
284 "The percentage of function, weighted by execution frequency, that \
285 must be covered by trace formation. Used when profile feedback is available",
287 DEFPARAM(TRACER_DYNAMIC_COVERAGE
,
288 "tracer-dynamic-coverage",
289 "The percentage of function, weighted by execution frequency, that \
290 must be covered by trace formation. Used when profile feedback is not available",
292 DEFPARAM(TRACER_MAX_CODE_GROWTH
,
293 "tracer-max-code-growth",
294 "Maximal code growth caused by tail duplication (in percent)",
296 DEFPARAM(TRACER_MIN_BRANCH_RATIO
,
297 "tracer-min-branch-ratio",
298 "Stop reverse growth if the reverse probability of best edge is less \
299 than this threshold (in percent)",
301 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK
,
302 "tracer-min-branch-probability-feedback",
303 "Stop forward growth if the probability of best edge is less than \
304 this threshold (in percent). Used when profile feedback is available",
306 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY
,
307 "tracer-min-branch-probability",
308 "Stop forward growth if the probability of best edge is less than \
309 this threshold (in percent). Used when profile feedback is not available",
312 /* The maximum number of incoming edges to consider for crossjumping.
*/
313 DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES
,
314 "max-crossjump-edges",
315 "The maximum number of incoming edges to consider for crossjumping",
318 /* The minimum number of matching instructions to consider for crossjumping.
*/
319 DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS
,
320 "min-crossjump-insns",
321 "The minimum number of matching instructions to consider for crossjumping",
324 /* The maximum length of path considered in cse.
*/
325 DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH
,
326 "max-cse-path-length",
327 "The maximum length of path considered in cse",
330 /* The cost of expression in loop invariant motion that is considered
332 DEFPARAM(PARAM_LIM_EXPENSIVE
,
334 "The minimum cost of an expensive expression in the loop invariant motion",
337 /* Bound on number of candidates for induction variables below that
338 all candidates are considered for each use in induction variable
341 DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND
,
342 "iv-consider-all-candidates-bound",
343 "Bound on number of candidates below that all candidates are considered in iv optimizations",
346 /* The induction variable optimizations give up on loops that contain more
347 induction variable uses.
*/
349 DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES
,
350 "iv-max-considered-uses",
351 "Bound on number of iv uses in loop optimized in iv optimizations",
354 /* The product of the next two is used to decide whether or not to
355 use .GLOBAL_VAR. See tree
-dfa.c.
*/
356 DEFPARAM(PARAM_GLOBAL_VAR_THRESHOLD
,
357 "global-var-threshold",
358 "Given N calls and V call-clobbered vars in a function. Use .GLOBAL_VAR if NxV is larger than this limit",
361 DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS
,
362 "max-cselib-memory-locations",
363 "The maximum memory locations recorded by cselib",
366 #ifdef ENABLE_GC_ALWAYS_COLLECT
367 # define GGC_MIN_EXPAND_DEFAULT
0
368 # define GGC_MIN_HEAPSIZE_DEFAULT
0
370 # define GGC_MIN_EXPAND_DEFAULT
30
371 # define GGC_MIN_HEAPSIZE_DEFAULT
4096
374 DEFPARAM(GGC_MIN_EXPAND
,
376 "Minimum heap expansion to trigger garbage collection, as \
377 a percentage of the total size of the heap",
378 GGC_MIN_EXPAND_DEFAULT
)
380 DEFPARAM(GGC_MIN_HEAPSIZE
,
382 "Minimum heap size before we start collecting garbage, in kilobytes",
383 GGC_MIN_HEAPSIZE_DEFAULT
)
385 #undef GGC_MIN_EXPAND_DEFAULT
386 #undef GGC_MIN_HEAPSIZE_DEFAULT
388 DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS
,
389 "max-reload-search-insns",
390 "The maximum number of instructions to search backward when looking for equivalent reload",
393 DEFPARAM(PARAM_MAX_ALIASED_VOPS
,
395 "The maximum number of virtual operands allowed to represent aliases before triggering alias grouping.",
398 DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS
,
399 "max-sched-region-blocks",
400 "The maximum number of blocks in a region to be considered for interblock scheduling",
403 DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS
,
404 "max-sched-region-insns",
405 "The maximum number of insns in a region to be considered for interblock scheduling",
408 /* INTEGER_CST nodes are shared for values
[{-1,0} .. N
) for
409 {signed
,unsigned
} integral types. This determines N.
410 Experimentation shows
256 to be a good value.
*/
411 DEFPARAM (PARAM_INTEGER_SHARE_LIMIT
,
412 "integer-share-limit",
413 "The upper bound for sharing integer constants",