gcc/params.def

   1 /* params.def - Run-time parameters.
   2    Copyright (C) 2001, 2002, 2004 Free Software Foundation, Inc.
   3    Written by Mark Mitchell <mark@codesourcery.com>.
   4
   5 This file is part of GCC.
   6
   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
  10 version.
  11
  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
  15 for more details.
  16
  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
  20 02111-1307, USA.
  21
  22 */
  23
  24 /* This file contains definitions for language-independent
  25    parameters.  The DEFPARAM macro takes 4 arguments:
  26
  27      - The enumeral corresponding to this parameter.
  28
  29      - The name that can be used to set this parameter using the
  30        command-line option `--param <name>=<value>'.
  31
  32      - A help string explaining how the parameter is used.
  33
  34      - A default value for the parameter.
  35
  36    Be sure to add an entry to invoke.texi summarizing the parameter.  */
  37
  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
  41    by the tree inliner.
  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
  50    gets decreased.  */
  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",
  54           500)
  55
  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"
  61    parameter.
  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",
  66           120)
  67
  68 /* For languages that (still) use the RTL inliner, we can specify
  69    limits for the RTL inliner separately.
  70    The parameter here defines the maximum number of RTL instructions
  71    a function may have to be eligible for inlining in the RTL inliner.
  72    The default value is 600.  */
  73 DEFPARAM (PARAM_MAX_INLINE_INSNS_RTL,
  74           "max-inline-insns-rtl",
  75           "The maximum number of instructions for the RTL inliner",
  76           600)
  77
  78 /* The maximum number of instructions to consider when looking for an
  79    instruction to fill a delay slot.  If more than this arbitrary
  80    number of instructions is searched, the time savings from filling
  81    the delay slot will be minimal so stop searching.  Increasing
  82    values mean more aggressive optimization, making the compile time
  83    increase with probably small improvement in executable run time.  */
  84 DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH,
  85           "max-delay-slot-insn-search",
  86           "The maximum number of instructions to consider to fill a delay slot",
  87           100)
  88
  89 /* When trying to fill delay slots, the maximum number of instructions
  90    to consider when searching for a block with valid live register
  91    information.  Increasing this arbitrarily chosen value means more
  92    aggressive optimization, increasing the compile time.  This
  93    parameter should be removed when the delay slot code is rewritten
  94    to maintain the control-flow graph.  */
  95 DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH,
  96          "max-delay-slot-live-search",
  97          "The maximum number of instructions to consider to find accurate live register information",
  98          333)
  99
 100 /* This parameter limits the number of branch elements that the
 101    scheduler will track anti-dependencies through without resetting
 102    the tracking mechanism.  Large functions with few calls or barriers
 103    can generate lists containing many 1000's of dependencies.  Generally
 104    the compiler either uses all available memory, or runs for far too long.  */
 105 DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH,
 106          "max-pending-list-length",
 107          "The maximum length of scheduling's pending operations list",
 108          32)
 109
 110 DEFPARAM(PARAM_LARGE_FUNCTION_INSNS,
 111          "large-function-insns",
 112          "The size of function body to be considered large",
 113          3000)
 114 DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH,
 115          "large-function-growth",
 116          "Maximal growth due to inlining of large function (in percent)",
 117          100)
 118 DEFPARAM(PARAM_INLINE_UNIT_GROWTH,
 119          "inline-unit-growth",
 120          "how much can given compilation unit grow because of the inlining (in percent)",
 121          50)
 122
 123 /* The GCSE optimization will be disabled if it would require
 124    significantly more memory than this value.  */
 125 DEFPARAM(PARAM_MAX_GCSE_MEMORY,
 126          "max-gcse-memory",
 127          "The maximum amount of memory to be allocated by GCSE",
 128          50 * 1024 * 1024)
 129 /* The number of repetitions of copy/const prop and PRE to run.  */
 130 DEFPARAM(PARAM_MAX_GCSE_PASSES,
 131         "max-gcse-passes",
 132         "The maximum number of passes to make when doing GCSE",
 133         1)
 134 /* This is the threshold ratio when to perform partial redundancy
 135    elimination after reload. We perform partial redundancy elimination
 136    when the following holds:
 137    (Redundant load execution count)
 138    ------------------------------- >= GCSE_AFTER_RELOAD_PARTIAL_FRACTION
 139    (Added loads execution count)                                          */
 140 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_PARTIAL_FRACTION,
 141         "gcse-after-reload-partial-fraction",
 142         "The threshold ratio for performing partial redundancy elimination \
 143          after reload.",
 144         3)
 145 /* This is the threshold ratio of the critical edges execution count compared to
 146    the redundant loads execution count that permits performing the load
 147    redundancy elimination in gcse after reload.  */
 148 DEFPARAM(PARAM_GCSE_AFTER_RELOAD_CRITICAL_FRACTION,
 149         "gcse-after-reload-critical-fraction",
 150         "The threshold ratio of critical edges execution count that permit \
 151          performing redundancy elimination after reload.",
 152         10)
 153 /* This parameter limits the number of insns in a loop that will be unrolled,
 154    and by how much the loop is unrolled.
 155
 156    This limit should be at most half of the peeling limits:  loop unroller
 157    decides to not unroll loops that iterate fewer than 2*number of allowed
 158    unrollings and thus we would have loops that are neither peeled or unrolled
 159    otherwise.  */
 160 DEFPARAM(PARAM_MAX_UNROLLED_INSNS,
 161          "max-unrolled-insns",
 162          "The maximum number of instructions to consider to unroll in a loop",
 163          200)
 164 /* This parameter limits how many times the loop is unrolled depending
 165    on number of insns really executed in each iteration.  */
 166 DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS,
 167          "max-average-unrolled-insns",
 168          "The maximum number of instructions to consider to unroll in a loop on average",
 169          80)
 170 /* The maximum number of unrollings of a single loop.  */
 171 DEFPARAM(PARAM_MAX_UNROLL_TIMES,
 172         "max-unroll-times",
 173         "The maximum number of unrollings of a single loop",
 174         8)
 175 /* The maximum number of insns of a peeled loop.  */
 176 DEFPARAM(PARAM_MAX_PEELED_INSNS,
 177         "max-peeled-insns",
 178         "The maximum number of insns of a peeled loop",
 179         400)
 180 /* The maximum number of peelings of a single loop.  */
 181 DEFPARAM(PARAM_MAX_PEEL_TIMES,
 182         "max-peel-times",
 183         "The maximum number of peelings of a single loop",
 184         16)
 185 /* The maximum number of insns of a peeled loop.  */
 186 DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS,
 187         "max-completely-peeled-insns",
 188         "The maximum number of insns of a completely peeled loop",
 189         400)
 190 /* The maximum number of peelings of a single loop that is peeled completely.  */
 191 DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES,
 192         "max-completely-peel-times",
 193         "The maximum number of peelings of a single loop that is peeled completely",
 194         16)
 195 /* The maximum number of insns of a peeled loop that rolls only once.  */
 196 DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS,
 197         "max-once-peeled-insns",
 198         "The maximum number of insns of a peeled loop that rolls only once",
 199         400)
 200
 201 /* The maximum number of insns of an unswitched loop.  */
 202 DEFPARAM(PARAM_MAX_UNSWITCH_INSNS,
 203         "max-unswitch-insns",
 204         "The maximum number of insns of an unswitched loop",
 205         50)
 206 /* The maximum level of recursion in unswitch_single_loop.  */
 207 DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL,
 208         "max-unswitch-level",
 209         "The maximum number of unswitchings in a single loop",
 210         3)
 211
 212 DEFPARAM(HOT_BB_COUNT_FRACTION,
 213          "hot-bb-count-fraction",
 214          "Select fraction of the maximal count of repetitions of basic block in \
 215 program given basic block needs to have to be considered hot",
 216          10000)
 217 DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
 218          "hot-bb-frequency-fraction",
 219          "Select fraction of the maximal frequency of executions of basic \
 220 block in function given basic block needs to have to be considered hot",
 221          1000)
 222 DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
 223          "tracer-dynamic-coverage-feedback",
 224          "The percentage of function, weighted by execution frequency, that \
 225 must be covered by trace formation. Used when profile feedback is available",
 226          95)
 227 DEFPARAM(TRACER_DYNAMIC_COVERAGE,
 228          "tracer-dynamic-coverage",
 229          "The percentage of function, weighted by execution frequency, that \
 230 must be covered by trace formation. Used when profile feedback is not available",
 231          75)
 232 DEFPARAM(TRACER_MAX_CODE_GROWTH,
 233          "tracer-max-code-growth",
 234          "Maximal code growth caused by tail duplication (in percent)",
 235          100)
 236 DEFPARAM(TRACER_MIN_BRANCH_RATIO,
 237          "tracer-min-branch-ratio",
 238          "Stop reverse growth if the reverse probability of best edge is less \
 239 than this threshold (in percent)",
 240          10)
 241 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
 242          "tracer-min-branch-probability-feedback",
 243          "Stop forward growth if the probability of best edge is less than \
 244 this threshold (in percent). Used when profile feedback is available",
 245          80)
 246 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
 247          "tracer-min-branch-probability",
 248          "Stop forward growth if the probability of best edge is less than \
 249 this threshold (in percent). Used when profile feedback is not available",
 250          50)
 251
 252 /* The maximum number of incoming edges to consider for crossjumping.  */
 253 DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
 254          "max-crossjump-edges",
 255          "The maximum number of incoming edges to consider for crossjumping",
 256          100)
 257
 258 /* The maximum length of path considered in cse.  */
 259 DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
 260          "max-cse-path-length",
 261          "The maximum length of path considered in cse",
 262          10)
 263
 264 DEFPARAM(PARAM_MAX_CSELIB_MEMORY_LOCATIONS,
 265          "max-cselib-memory-locations",
 266          "The maximum memory locations recorded by cselib",
 267          500)
 268
 269 #ifdef ENABLE_GC_ALWAYS_COLLECT
 270 # define GGC_MIN_EXPAND_DEFAULT 0
 271 # define GGC_MIN_HEAPSIZE_DEFAULT 0
 272 #else
 273 # define GGC_MIN_EXPAND_DEFAULT 30
 274 # define GGC_MIN_HEAPSIZE_DEFAULT 4096
 275 #endif
 276
 277 DEFPARAM(GGC_MIN_EXPAND,
 278          "ggc-min-expand",
 279          "Minimum heap expansion to trigger garbage collection, as \
 280 a percentage of the total size of the heap",
 281          GGC_MIN_EXPAND_DEFAULT)
 282
 283 DEFPARAM(GGC_MIN_HEAPSIZE,
 284          "ggc-min-heapsize",
 285          "Minimum heap size before we start collecting garbage, in kilobytes",
 286          GGC_MIN_HEAPSIZE_DEFAULT)
 287
 288 #undef GGC_MIN_EXPAND_DEFAULT
 289 #undef GGC_MIN_HEAPSIZE_DEFAULT
 290
 291 DEFPARAM(PARAM_MAX_RELOAD_SEARCH_INSNS,
 292          "max-reload-search-insns",
 293          "The maximum number of instructions to search backward when looking for equivalent reload",
 294          100)
 295
 296 DEFPARAM(PARAM_MAX_SCHED_REGION_BLOCKS,
 297          "max-sched-region-blocks",
 298          "The maximum number of blocks in a region to be considered for interblock scheduling",
 299          10)
 300
 301 DEFPARAM(PARAM_MAX_SCHED_REGION_INSNS,
 302          "max-sched-region-insns",
 303          "The maximum number of insns in a region to be considered for interblock scheduling",
 304          100)
 305
 306 /*
 307 Local variables:
 308 mode:c
 309 End: */