1 /* params.def - Run-time parameters.
2 Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007
3 Free Software Foundation, Inc.
4 Written by Mark Mitchell <mark@codesourcery.com>.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* This file contains definitions for language-independent
23 parameters. The DEFPARAM macro takes 6 arguments:
25 - The enumeral corresponding to this parameter.
27 - The name that can be used to set this parameter using the
28 command-line option `--param <name>=<value>'.
30 - A help string explaining how the parameter is used.
32 - A default value for the parameter.
34 - The minimum acceptable value for the parameter.
36 - The maximum acceptable value for the parameter (if greater than
39 Be sure to add an entry to invoke.texi summarizing the parameter. */
41 /* The maximum structure size at which the scalar replacement of
42 aggregates (SRA) pass will perform block copies. The default
43 value, 0, implies that GCC will select the most appropriate size
45 DEFPARAM (PARAM_SRA_MAX_STRUCTURE_SIZE,
46 "sra-max-structure-size",
47 "The maximum structure size (in bytes) for which GCC will "
48 "use by-element copies",
51 /* The maximum number of structure fields which the SRA pass will
52 instantiate to avoid block copies. The default value, 0, implies
53 that GCC will select the appropriate value itself. */
54 DEFPARAM (PARAM_SRA_MAX_STRUCTURE_COUNT,
55 "sra-max-structure-count",
56 "The maximum number of structure fields for which GCC will "
57 "use by-element copies",
60 /* The ratio between instantiated fields and the complete structure
61 size. We say that if the ratio of the number of bytes in
62 instantiated fields to the number of bytes in the complete
63 structure exceeds this parameter, or if the number of instantiated
64 fields to the total number of fields exceeds this parameter, then
65 block copies are not used. The default is 75%. */
66 DEFPARAM (PARAM_SRA_FIELD_STRUCTURE_RATIO,
67 "sra-field-structure-ratio",
68 "The threshold ratio between instantiated fields and the total structure size",
71 /* The threshold ratio between current and hottest structure counts.
72 We say that if the ratio of the current structure count,
73 calculated by profiling, to the hottest structure count
74 in the program is less than this parameter, then structure
75 reorganization is not applied. The default is 10%. */
76 DEFPARAM (PARAM_STRUCT_REORG_COLD_STRUCT_RATIO,
77 "struct-reorg-cold-struct-ratio",
78 "The threshold ratio between current and hottest structure counts",
81 /* The single function inlining limit. This is the maximum size
82 of a function counted in internal gcc instructions (not in
83 real machine instructions) that is eligible for inlining
85 The default value is 450.
86 Only functions marked inline (or methods defined in the class
87 definition for C++) are affected by this.
88 There are more restrictions to inlining: If inlined functions
89 call other functions, the already inlined instructions are
90 counted and once the recursive inline limit (see
91 "max-inline-insns" parameter) is exceeded, the acceptable size
93 DEFPARAM (PARAM_MAX_INLINE_INSNS_SINGLE,
94 "max-inline-insns-single",
95 "The maximum number of instructions in a single function eligible for inlining",
98 /* The single function inlining limit for functions that are
99 inlined by virtue of -finline-functions (-O3).
100 This limit should be chosen to be below or equal to the limit
101 that is applied to functions marked inlined (or defined in the
102 class declaration in C++) given by the "max-inline-insns-single"
104 The default value is 90. */
105 DEFPARAM (PARAM_MAX_INLINE_INSNS_AUTO,
106 "max-inline-insns-auto",
107 "The maximum number of instructions when automatically inlining",
110 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE,
111 "max-inline-insns-recursive",
112 "The maximum number of instructions inline function can grow to via recursive inlining",
115 DEFPARAM (PARAM_MAX_INLINE_INSNS_RECURSIVE_AUTO,
116 "max-inline-insns-recursive-auto",
117 "The maximum number of instructions non-inline function can grow to via recursive inlining",
120 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH,
121 "max-inline-recursive-depth",
122 "The maximum depth of recursive inlining for inline functions",
125 DEFPARAM (PARAM_MAX_INLINE_RECURSIVE_DEPTH_AUTO,
126 "max-inline-recursive-depth-auto",
127 "The maximum depth of recursive inlining for non-inline functions",
130 DEFPARAM (PARAM_MIN_INLINE_RECURSIVE_PROBABILITY,
131 "min-inline-recursive-probability",
132 "Inline recursively only when the probability of call being executed exceeds the parameter",
135 /* Limit the number of expansions created by the variable expansion
136 optimization to avoid register pressure. */
137 DEFPARAM (PARAM_MAX_VARIABLE_EXPANSIONS,
138 "max-variable-expansions-in-unroller",
139 "If -fvariable-expansion-in-unroller is used, the maximum number of times that an individual variable will be expanded during loop unrolling",
142 /* Limit loop autovectorization to loops with large enough iteration count. */
143 DEFPARAM (PARAM_MIN_VECT_LOOP_BOUND,
144 "min-vect-loop-bound",
145 "If -ftree-vectorize is used, the minimal loop bound of a loop to be considered for vectorization",
148 /* The maximum number of instructions to consider when looking for an
149 instruction to fill a delay slot. If more than this arbitrary
150 number of instructions is searched, the time savings from filling
151 the delay slot will be minimal so stop searching. Increasing
152 values mean more aggressive optimization, making the compile time
153 increase with probably small improvement in executable run time. */
154 DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH,
155 "max-delay-slot-insn-search",
156 "The maximum number of instructions to consider to fill a delay slot",
159 /* When trying to fill delay slots, the maximum number of instructions
160 to consider when searching for a block with valid live register
161 information. Increasing this arbitrarily chosen value means more
162 aggressive optimization, increasing the compile time. This
163 parameter should be removed when the delay slot code is rewritten
164 to maintain the control-flow graph. */
165 DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH,
166 "max-delay-slot-live-search",
167 "The maximum number of instructions to consider to find accurate live register information",
170 /* This parameter limits the number of branch elements that the
171 scheduler will track anti-dependencies through without resetting
172 the tracking mechanism. Large functions with few calls or barriers
173 can generate lists containing many 1000's of dependencies. Generally
174 the compiler either uses all available memory, or runs for far too long. */
175 DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH,
176 "max-pending-list-length",
177 "The maximum length of scheduling's pending operations list",
180 DEFPARAM(PARAM_LARGE_FUNCTION_INSNS,
181 "large-function-insns",
182 "The size of function body to be considered large",
184 DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH,
185 "large-function-growth",
186 "Maximal growth due to inlining of large function (in percent)",
188 DEFPARAM(PARAM_LARGE_UNIT_INSNS,
190 "The size of translation unit to be considered large",
192 DEFPARAM(PARAM_INLINE_UNIT_GROWTH,
193 "inline-unit-growth",
194 "how much can given compilation unit grow because of the inlining (in percent)",
196 DEFPARAM(PARAM_IPCP_UNIT_GROWTH,
198 "how much can given compilation unit grow because of the interprocedural constant propagation (in percent)",
200 DEFPARAM(PARAM_INLINE_CALL_COST,
202 "expense of call operation relative to ordinary arithmetic operations",
204 DEFPARAM(PARAM_LARGE_STACK_FRAME,
206 "The size of stack frame to be considered large",
208 DEFPARAM(PARAM_STACK_FRAME_GROWTH,
209 "large-stack-frame-growth",
210 "Maximal stack frame growth due to inlining (in percent)",
213 /* The GCSE optimization will be disabled if it would require
214 significantly more memory than this value. */
215 DEFPARAM(PARAM_MAX_GCSE_MEMORY,
217 "The maximum amount of memory to be allocated by GCSE",
218 50 * 1024 * 1024, 0, 0)
219 /* The number of repetitions of copy/const prop and PRE to run. */
220 DEFPARAM(PARAM_MAX_GCSE_PASSES,
222 "The maximum number of passes to make when doing GCSE",
224 /* This is the threshold ratio when to perform partial redundancy
225 elimination after reload. We perform partial redundancy elimination
226 when the following holds:
227 (Redundant load execution count)
228 ------------------------------- >= GCSE_AFTER_RELOAD_PARTIAL_FRACTION
229 (Added loads execution count) */
230 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_PARTIAL_FRACTION,
231 "gcse-after-reload-partial-fraction",
232 "The threshold ratio for performing partial redundancy elimination after reload",
234 /* This is the threshold ratio of the critical edges execution count compared to
235 the redundant loads execution count that permits performing the load
236 redundancy elimination in gcse after reload. */
237 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_CRITICAL_FRACTION,
238 "gcse-after-reload-critical-fraction",
239 "The threshold ratio of critical edges execution count that permit performing redundancy elimination after reload",
241 /* This parameter limits the number of insns in a loop that will be unrolled,
242 and by how much the loop is unrolled.
244 This limit should be at most half of the peeling limits: loop unroller
245 decides to not unroll loops that iterate fewer than 2*number of allowed
246 unrollings and thus we would have loops that are neither peeled or unrolled
248 DEFPARAM(PARAM_MAX_UNROLLED_INSNS,
249 "max-unrolled-insns",
250 "The maximum number of instructions to consider to unroll in a loop",
252 /* This parameter limits how many times the loop is unrolled depending
253 on number of insns really executed in each iteration. */
254 DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS,
255 "max-average-unrolled-insns",
256 "The maximum number of instructions to consider to unroll in a loop on average",
258 /* The maximum number of unrollings of a single loop. */
259 DEFPARAM(PARAM_MAX_UNROLL_TIMES,
261 "The maximum number of unrollings of a single loop",
263 /* The maximum number of insns of a peeled loop. */
264 DEFPARAM(PARAM_MAX_PEELED_INSNS,
266 "The maximum number of insns of a peeled loop",
268 /* The maximum number of peelings of a single loop. */
269 DEFPARAM(PARAM_MAX_PEEL_TIMES,
271 "The maximum number of peelings of a single loop",
273 /* The maximum number of insns of a peeled loop. */
274 DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS,
275 "max-completely-peeled-insns",
276 "The maximum number of insns of a completely peeled loop",
278 /* The maximum number of peelings of a single loop that is peeled completely. */
279 DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES,
280 "max-completely-peel-times",
281 "The maximum number of peelings of a single loop that is peeled completely",
283 /* The maximum number of insns of a peeled loop that rolls only once. */
284 DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS,
285 "max-once-peeled-insns",
286 "The maximum number of insns of a peeled loop that rolls only once",
289 /* The maximum number of insns of an unswitched loop. */
290 DEFPARAM(PARAM_MAX_UNSWITCH_INSNS,
291 "max-unswitch-insns",
292 "The maximum number of insns of an unswitched loop",
294 /* The maximum level of recursion in unswitch_single_loop. */
295 DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL,
296 "max-unswitch-level",
297 "The maximum number of unswitchings in a single loop",
300 /* The maximum number of iterations of a loop the brute force algorithm
301 for analysis of # of iterations of the loop tries to evaluate. */
302 DEFPARAM(PARAM_MAX_ITERATIONS_TO_TRACK,
303 "max-iterations-to-track",
304 "Bound on the number of iterations the brute force # of iterations analysis algorithm evaluates",
306 /* A cutoff to avoid costly computations of the number of iterations in
307 the doloop transformation. */
308 DEFPARAM(PARAM_MAX_ITERATIONS_COMPUTATION_COST,
309 "max-iterations-computation-cost",
310 "Bound on the cost of an expression to compute the number of iterations",
313 /* This parameter is used to tune SMS MAX II calculations. */
314 DEFPARAM(PARAM_SMS_MAX_II_FACTOR,
316 "A factor for tuning the upper bound that swing modulo scheduler uses for scheduling a loop",
318 DEFPARAM(PARAM_SMS_DFA_HISTORY,
320 "The number of cycles the swing modulo scheduler considers when checking conflicts using DFA",
322 DEFPARAM(PARAM_SMS_LOOP_AVERAGE_COUNT_THRESHOLD,
323 "sms-loop-average-count-threshold",
324 "A threshold on the average loop count considered by the swing modulo scheduler",
327 DEFPARAM(HOT_BB_COUNT_FRACTION,
328 "hot-bb-count-fraction",
329 "Select fraction of the maximal count of repetitions of basic block in program given basic block needs to have to be considered hot",
331 DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
332 "hot-bb-frequency-fraction",
333 "Select fraction of the maximal frequency of executions of basic block in function given basic block needs to have to be considered hot",
336 DEFPARAM (PARAM_ALIGN_THRESHOLD,
338 "Select fraction of the maximal frequency of executions of basic block in function given basic block get alignment",
341 DEFPARAM (PARAM_ALIGN_LOOP_ITERATIONS,
342 "align-loop-iterations",
343 "Loops iterating at least selected number of iterations will get loop alignement.",
346 /* For guessed profiles, the loops having unknown number of iterations
347 are predicted to iterate relatively few (10) times at average.
348 For functions containing one loop with large known number of iterations
349 and other loops having unbounded loops we would end up predicting all
350 the other loops cold that is not usually the case. So we need to artificially
353 We need to cut the maximal predicted iterations to large enough iterations
354 so the loop appears important, but safely within HOT_BB_COUNT_FRACTION
357 DEFPARAM(PARAM_MAX_PREDICTED_ITERATIONS,
358 "max-predicted-iterations",
359 "The maximum number of loop iterations we predict statically",
361 DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
362 "tracer-dynamic-coverage-feedback",
363 "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is available",
365 DEFPARAM(TRACER_DYNAMIC_COVERAGE,
366 "tracer-dynamic-coverage",
367 "The percentage of function, weighted by execution frequency, that must be covered by trace formation. Used when profile feedback is not available",
369 DEFPARAM(TRACER_MAX_CODE_GROWTH,
370 "tracer-max-code-growth",
371 "Maximal code growth caused by tail duplication (in percent)",
373 DEFPARAM(TRACER_MIN_BRANCH_RATIO,
374 "tracer-min-branch-ratio",
375 "Stop reverse growth if the reverse probability of best edge is less than this threshold (in percent)",
377 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
378 "tracer-min-branch-probability-feedback",
379 "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is available",
381 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
382 "tracer-min-branch-probability",
383 "Stop forward growth if the probability of best edge is less than this threshold (in percent). Used when profile feedback is not available",
386 /* The maximum number of incoming edges to consider for crossjumping. */
387 DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
388 "max-crossjump-edges",
389 "The maximum number of incoming edges to consider for crossjumping",
392 /* The minimum number of matching instructions to consider for crossjumping. */
393 DEFPARAM(PARAM_MIN_CROSSJUMP_INSNS,
394 "min-crossjump-insns",
395 "The minimum number of matching instructions to consider for crossjumping",
398 /* The maximum number expansion factor when copying basic blocks. */
399 DEFPARAM(PARAM_MAX_GROW_COPY_BB_INSNS,
400 "max-grow-copy-bb-insns",
401 "The maximum expansion factor when copying basic blocks",
404 /* The maximum number of insns to duplicate when unfactoring computed gotos. */
405 DEFPARAM(PARAM_MAX_GOTO_DUPLICATION_INSNS,
406 "max-goto-duplication-insns",
407 "The maximum number of insns to duplicate when unfactoring computed gotos",
410 /* The maximum length of path considered in cse. */
411 DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
412 "max-cse-path-length",
413 "The maximum length of path considered in cse",
415 DEFPARAM(PARAM_MAX_CSE_INSNS,
417 "The maximum instructions CSE process before flushing",
420 /* The cost of expression in loop invariant motion that is considered
422 DEFPARAM(PARAM_LIM_EXPENSIVE,
424 "The minimum cost of an expensive expression in the loop invariant motion",
427 /* Bound on number of candidates for induction variables below that
428 all candidates are considered for each use in induction variable
431 DEFPARAM(PARAM_IV_CONSIDER_ALL_CANDIDATES_BOUND,
432 "iv-consider-all-candidates-bound",
433 "Bound on number of candidates below that all candidates are considered in iv optimizations",
436 /* The induction variable optimizations give up on loops that contain more
437 induction variable uses. */
439 DEFPARAM(PARAM_IV_MAX_CONSIDERED_USES,
440 "iv-max-considered-uses",
441 "Bound on number of iv uses in loop optimized in iv optimizations",
444 /* If there are at most this number of ivs in the set, try removing unnecessary
445 ivs from the set always. */
447 DEFPARAM(PARAM_IV_ALWAYS_PRUNE_CAND_SET_BOUND,
448 "iv-always-prune-cand-set-bound",
449 "If number of candidates in the set is smaller, we always try to remove unused ivs during its optimization",
452 DEFPARAM(PARAM_SCEV_MAX_EXPR_SIZE,
453 "scev-max-expr-size",
454 "Bound on size of expressions used in the scalar evolutions analyzer",
457 DEFPARAM(PARAM_OMEGA_MAX_VARS,
459 "Bound on the number of variables in Omega constraint systems",
462 DEFPARAM(PARAM_OMEGA_MAX_GEQS,
464 "Bound on the number of inequalities in Omega constraint systems",
467 DEFPARAM(PARAM_OMEGA_MAX_EQS,
469 "Bound on the number of equalities in Omega constraint systems",
472 DEFPARAM(PARAM_OMEGA_MAX_WILD_CARDS,
473 "omega-max-wild-cards",
474 "Bound on the number of wild cards in Omega constraint systems",
477 DEFPARAM(PARAM_OMEGA_HASH_TABLE_SIZE,
478 "omega-hash-table-size",
479 "Bound on the size of the hash table in Omega constraint systems",
482 DEFPARAM(PARAM_OMEGA_MAX_KEYS,
484 "Bound on the number of keys in Omega constraint systems",
487 DEFPARAM(PARAM_OMEGA_ELIMINATE_REDUNDANT_CONSTRAINTS,
488 "omega-eliminate-redundant-constraints",
489 "When set to 1, use expensive methods to eliminate all redundant constraints",
492 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIGNMENT_CHECKS,
493 "vect-max-version-for-alignment-checks",
494 "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alignment check",
497 DEFPARAM(PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS,
498 "vect-max-version-for-alias-checks",
499 "Bound on number of runtime checks inserted by the vectorizer's loop versioning for alias check",
502 DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS,
503 "max-cselib-memory-locations",
504 "The maximum memory locations recorded by cselib",
507 #ifdef ENABLE_GC_ALWAYS_COLLECT
508 # define GGC_MIN_EXPAND_DEFAULT 0
509 # define GGC_MIN_HEAPSIZE_DEFAULT 0
511 # define GGC_MIN_EXPAND_DEFAULT 30
512 # define GGC_MIN_HEAPSIZE_DEFAULT 4096
515 DEFPARAM(GGC_MIN_EXPAND,
517 "Minimum heap expansion to trigger garbage collection, as a percentage of the total size of the heap",
518 GGC_MIN_EXPAND_DEFAULT, 0, 0)
520 DEFPARAM(GGC_MIN_HEAPSIZE,
522 "Minimum heap size before we start collecting garbage, in kilobytes",
523 GGC_MIN_HEAPSIZE_DEFAULT, 0, 0)
525 #undef GGC_MIN_EXPAND_DEFAULT
526 #undef GGC_MIN_HEAPSIZE_DEFAULT
528 DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
529 "max-reload-search-insns",
530 "The maximum number of instructions to search backward when looking for equivalent reload",
533 DEFPARAM(PARAM_MAX_ALIASED_VOPS,
535 "The maximum number of virtual operators that a function is allowed to have before triggering memory partitioning heuristics",
538 DEFPARAM(PARAM_AVG_ALIASED_VOPS,
540 "The average number of virtual operators that memory statements are allowed to have before triggering memory partitioning heuristics",
543 DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS,
544 "max-sched-region-blocks",
545 "The maximum number of blocks in a region to be considered for interblock scheduling",
548 DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS,
549 "max-sched-region-insns",
550 "The maximum number of insns in a region to be considered for interblock scheduling",
553 DEFPARAM(PARAM_MIN_SPEC_PROB,
555 "The minimum probability of reaching a source block for interblock speculative scheduling",
558 DEFPARAM(PARAM_MAX_SCHED_EXTEND_REGIONS_ITERS,
559 "max-sched-extend-regions-iters",
560 "The maximum number of iterations through CFG to extend regions",
563 DEFPARAM(PARAM_MAX_SCHED_INSN_CONFLICT_DELAY,
564 "max-sched-insn-conflict-delay",
565 "The maximum conflict delay for an insn to be considered for speculative motion",
568 DEFPARAM(PARAM_SCHED_SPEC_PROB_CUTOFF,
569 "sched-spec-prob-cutoff",
570 "The minimal probability of speculation success (in percents), so that speculative insn will be scheduled.",
573 DEFPARAM(PARAM_MAX_LAST_VALUE_RTL,
574 "max-last-value-rtl",
575 "The maximum number of RTL nodes that can be recorded as combiner's last value",
578 /* INTEGER_CST nodes are shared for values [{-1,0} .. N) for
579 {signed,unsigned} integral types. This determines N.
580 Experimentation shows 256 to be a good value. */
581 DEFPARAM (PARAM_INTEGER_SHARE_LIMIT,
582 "integer-share-limit",
583 "The upper bound for sharing integer constants",
586 /* Incremental SSA updates for virtual operands may be very slow if
587 there is a large number of mappings to process. In those cases, it
588 is faster to rewrite the virtual symbols from scratch as if they
589 had been recently introduced. This heuristic cannot be applied to
590 SSA mappings for real SSA names, only symbols kept in FUD chains.
592 PARAM_MIN_VIRTUAL_MAPPINGS specifies the minimum number of virtual
593 mappings that should be registered to trigger the heuristic.
595 PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO specifies the ratio between
596 mappings and symbols. If the number of virtual mappings is
597 PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO bigger than the number of
598 virtual symbols to be updated, then the updater switches to a full
599 update for those symbols. */
600 DEFPARAM (PARAM_MIN_VIRTUAL_MAPPINGS,
601 "min-virtual-mappings",
602 "Minimum number of virtual mappings to consider switching to full virtual renames",
605 DEFPARAM (PARAM_VIRTUAL_MAPPINGS_TO_SYMS_RATIO,
606 "virtual-mappings-ratio",
607 "Ratio between virtual mappings and virtual symbols to do full virtual renames",
610 DEFPARAM (PARAM_SSP_BUFFER_SIZE,
612 "The lower bound for a buffer to be considered for stack smashing protection",
615 /* When we thread through a block we have to make copies of the
616 statements within the block. Clearly for large blocks the code
619 PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS specifies the maximum number
620 of statements and PHI nodes allowed in a block which is going to
621 be duplicated for thread jumping purposes.
623 Some simple analysis showed that more than 99% of the jump
624 threading opportunities are for blocks with less than 15
625 statements. So we can get the benefits of jump threading
626 without excessive code bloat for pathological cases with the
627 throttle set at 15 statements. */
628 DEFPARAM (PARAM_MAX_JUMP_THREAD_DUPLICATION_STMTS,
629 "max-jump-thread-duplication-stmts",
630 "Maximum number of statements allowed in a block that needs to be duplicated when threading jumps",
633 /* This is the maximum number of fields a variable may have before the pointer analysis machinery
634 will stop trying to treat it in a field-sensitive manner.
635 There are programs out there with thousands of fields per structure, and handling them
636 field-sensitively is not worth the cost. */
637 DEFPARAM (PARAM_MAX_FIELDS_FOR_FIELD_SENSITIVE,
638 "max-fields-for-field-sensitive",
639 "Maximum number of fields in a structure before pointer analysis treats the structure as a single variable",
642 DEFPARAM(PARAM_MAX_SCHED_READY_INSNS,
643 "max-sched-ready-insns",
644 "The maximum number of instructions ready to be issued to be considered by the scheduler during the first scheduling pass",
647 /* Prefetching and cache-optimizations related parameters. Default values are
648 usually set by machine description. */
650 /* The number of insns executed before prefetch is completed. */
652 DEFPARAM (PARAM_PREFETCH_LATENCY,
654 "The number of insns executed before prefetch is completed",
657 /* The number of prefetches that can run at the same time. */
659 DEFPARAM (PARAM_SIMULTANEOUS_PREFETCHES,
660 "simultaneous-prefetches",
661 "The number of prefetches that can run at the same time",
664 /* The size of L1 cache in kB. */
666 DEFPARAM (PARAM_L1_CACHE_SIZE,
668 "The size of L1 cache",
671 /* The size of L1 cache line in bytes. */
673 DEFPARAM (PARAM_L1_CACHE_LINE_SIZE,
674 "l1-cache-line-size",
675 "The size of L1 cache line",
678 /* The size of L2 cache in kB. */
680 DEFPARAM (PARAM_L2_CACHE_SIZE,
682 "The size of L2 cache",
685 /* Whether we should use canonical types rather than deep "structural"
686 type checking. Setting this value to 1 (the default) improves
687 compilation performance in the C++ and Objective-C++ front end;
688 this value should only be set to zero to work around bugs in the
689 canonical type system by disabling it. */
691 DEFPARAM (PARAM_USE_CANONICAL_TYPES,
692 "use-canonical-types",
693 "Whether to use canonical types",
696 DEFPARAM (PARAM_MAX_PARTIAL_ANTIC_LENGTH,
697 "max-partial-antic-length",
698 "Maximum length of partial antic set when performing tree pre optimization",
701 /* The following is used as a stop-gap limit for cases where really huge
702 SCCs blow up memory and compile-time use too much. If we hit this limit,
703 SCCVN and such FRE and PRE will be not done at all for the current
706 DEFPARAM (PARAM_SCCVN_MAX_SCC_SIZE,
707 "sccvn-max-scc-size",
708 "Maximum size of a SCC before SCCVN stops processing a function",
712 DEFPARAM (PARAM_DF_DOUBLE_QUEUE_THRESHOLD_FACTOR,
713 "df-double-queue-threshold-factor",
714 "Multiplier used for determining the double-queueing threshold",
717 /* Switch initialization conversion will refuse to create arrays that are
718 bigger than this parameter times the number of switch branches. */
720 DEFPARAM (PARAM_SWITCH_CONVERSION_BRANCH_RATIO,
721 "switch-conversion-max-branch-ratio",
722 "The maximum ratio between array size and switch branches for "
723 "a switch conversion to take place",