gcc/params.def

   1 /* params.def - Run-time parameters.
   2    Copyright (C) 2001, 2002 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 100.
  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 100.  */
  63 DEFPARAM (PARAM_MAX_INLINE_INSNS_AUTO,
  64           "max-inline-insns-auto",
  65           "The maximum number of instructions when automatically inlining",
  66           150)
  67
  68 /* The repeated inlining limit.  After this number of instructions
  69    (in the internal gcc representation, not real machine instructions)
  70    got inlined by repeated inlining, gcc starts to decrease the maximum
  71    number of inlinable instructions in the tree inliner.
  72    This is done by a linear function, see "max-inline-slope" parameter.
  73    It is necessary in order to limit the compile-time resources, that
  74    could otherwise become very high.
  75    It is recommended to set this value to twice the value of the single
  76    function limit (set by the "max-inline-insns-single" parameter) or
  77    higher.  The default value is 200.
  78    Higher values mean that more inlining is done, resulting in
  79    better performance of the code, at the expense of higher
  80    compile-time resource (time, memory) requirements and larger
  81    binaries.  */
  82 DEFPARAM (PARAM_MAX_INLINE_INSNS,
  83           "max-inline-insns",
  84           "The maximum number of instructions by repeated inlining before gcc starts to throttle inlining",
  85           200)
  86
  87 /* For languages that (still) use the RTL inliner, we can specify
  88    limits for the RTL inliner separately.
  89    The parameter here defines the maximum number of RTL instructions
  90    a function may have to be eligible for inlining in the RTL inliner.
  91    The default value is 600.  */
  92 DEFPARAM (PARAM_MAX_INLINE_INSNS_RTL,
  93           "max-inline-insns-rtl",
  94           "The maximum number of instructions for the RTL inliner",
  95           600)
  96
  97 /* The maximum number of instructions to consider when looking for an
  98    instruction to fill a delay slot.  If more than this arbitrary
  99    number of instructions is searched, the time savings from filling
 100    the delay slot will be minimal so stop searching.  Increasing
 101    values mean more aggressive optimization, making the compile time
 102    increase with probably small improvement in executable run time.  */
 103 DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH,
 104           "max-delay-slot-insn-search",
 105           "The maximum number of instructions to consider to fill a delay slot",
 106           100)
 107
 108 /* When trying to fill delay slots, the maximum number of instructions
 109    to consider when searching for a block with valid live register
 110    information.  Increasing this arbitrarily chosen value means more
 111    aggressive optimization, increasing the compile time.  This
 112    parameter should be removed when the delay slot code is rewritten
 113    to maintain the control-flow graph.  */
 114 DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH,
 115          "max-delay-slot-live-search",
 116          "The maximum number of instructions to consider to find accurate live register information",
 117          333)
 118
 119 /* This parameter limits the number of branch elements that the
 120    scheduler will track anti-dependencies through without resetting
 121    the tracking mechanism.  Large functions with few calls or barriers
 122    can generate lists containing many 1000's of dependencies.  Generally
 123    the compiler either uses all available memory, or runs for far too long.  */
 124 DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH,
 125          "max-pending-list-length",
 126          "The maximum length of scheduling's pending operations list",
 127          32)
 128
 129 DEFPARAM(PARAM_LARGE_FUNCTION_INSNS,
 130          "large-function-insns",
 131          "The size of function body to be considered large",
 132          10000)
 133 DEFPARAM(PARAM_LARGE_FUNCTION_GROWTH,
 134          "large-function-growth",
 135          "Maximal growth due to inlining of large function (in percent)",
 136          100)
 137 DEFPARAM(PARAM_INLINE_UNIT_GROWTH,
 138          "inline-unit-growth",
 139          "how much can given compilation unit grow because of the inlining (in percent)",
 140          50)
 141
 142 /* The GCSE optimization will be disabled if it would require
 143    significantly more memory than this value.  */
 144 DEFPARAM(PARAM_MAX_GCSE_MEMORY,
 145          "max-gcse-memory",
 146          "The maximum amount of memory to be allocated by GCSE",
 147          50 * 1024 * 1024)
 148 /* The number of repetitions of copy/const prop and PRE to run.  */
 149 DEFPARAM(PARAM_MAX_GCSE_PASSES,
 150         "max-gcse-passes",
 151         "The maximum number of passes to make when doing GCSE",
 152         1)
 153
 154 /* This parameter limits the number of insns in a loop that will be unrolled,
 155    and by how much the loop is unrolled.  */
 156 DEFPARAM(PARAM_MAX_UNROLLED_INSNS,
 157          "max-unrolled-insns",
 158          "The maximum number of instructions to consider to unroll in a loop",
 159          200)
 160 /* This parameter limits how many times the loop is unrolled depending
 161    on number of insns really executed in each iteration.  */
 162 DEFPARAM(PARAM_MAX_AVERAGE_UNROLLED_INSNS,
 163          "max-average-unrolled-insns",
 164          "The maximum number of instructions to consider to unroll in a loop on average",
 165          80)
 166 /* The maximum number of unrollings of a single loop.  */
 167 DEFPARAM(PARAM_MAX_UNROLL_TIMES,
 168         "max-unroll-times",
 169         "The maximum number of unrollings of a single loop",
 170         8)
 171 /* The maximum number of insns of a peeled loop.  */
 172 DEFPARAM(PARAM_MAX_PEELED_INSNS,
 173         "max-peeled-insns",
 174         "The maximum number of insns of a peeled loop",
 175         120)
 176 /* The maximum number of peelings of a single loop.  */
 177 DEFPARAM(PARAM_MAX_PEEL_TIMES,
 178         "max-peel-times",
 179         "The maximum number of peelings of a single loop",
 180         16)
 181 /* The maximum number of insns of a peeled loop.  */
 182 DEFPARAM(PARAM_MAX_COMPLETELY_PEELED_INSNS,
 183         "max-completely-peeled-insns",
 184         "The maximum number of insns of a completely peeled loop",
 185         120)
 186 /* The maximum number of peelings of a single loop that is peeled completely.  */
 187 DEFPARAM(PARAM_MAX_COMPLETELY_PEEL_TIMES,
 188         "max-completely-peel-times",
 189         "The maximum number of peelings of a single loop that is peeled completely",
 190         16)
 191 /* The maximum number of insns of a peeled loop that rolls only once.  */
 192 DEFPARAM(PARAM_MAX_ONCE_PEELED_INSNS,
 193         "max-once-peeled-insns",
 194         "The maximum number of insns of a peeled loop that rolls only once",
 195         200)
 196
 197 /* The maximum number of insns of an unswitched loop.  */
 198 DEFPARAM(PARAM_MAX_UNSWITCH_INSNS,
 199         "max-unswitch-insns",
 200         "The maximum number of insns of an unswitched loop",
 201         50)
 202 /* The maximum level of recursion in unswitch_single_loop.  */
 203 DEFPARAM(PARAM_MAX_UNSWITCH_LEVEL,
 204         "max-unswitch-level",
 205         "The maximum number of unswitchings in a single loop",
 206         3)
 207
 208 DEFPARAM(HOT_BB_COUNT_FRACTION,
 209          "hot-bb-count-fraction",
 210          "Select fraction of the maximal count of repetitions of basic block in \
 211 program given basic block needs to have to be considered hot",
 212          10000)
 213 DEFPARAM(HOT_BB_FREQUENCY_FRACTION,
 214          "hot-bb-frequency-fraction",
 215          "Select fraction of the maximal frequency of executions of basic \
 216 block in function given basic block needs to have to be considered hot",
 217          1000)
 218 DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK,
 219          "tracer-dynamic-coverage-feedback",
 220          "The percentage of function, weighted by execution frequency, that \
 221 must be covered by trace formation. Used when profile feedback is available",
 222          95)
 223 DEFPARAM(TRACER_DYNAMIC_COVERAGE,
 224          "tracer-dynamic-coverage",
 225          "The percentage of function, weighted by execution frequency, that \
 226 must be covered by trace formation. Used when profile feedback is not available",
 227          75)
 228 DEFPARAM(TRACER_MAX_CODE_GROWTH,
 229          "tracer-max-code-growth",
 230          "Maximal code growth caused by tail duplication (in percent)",
 231          100)
 232 DEFPARAM(TRACER_MIN_BRANCH_RATIO,
 233          "tracer-min-branch-ratio",
 234          "Stop reverse growth if the reverse probability of best edge is less \
 235 than this threshold (in percent)",
 236          10)
 237 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK,
 238          "tracer-min-branch-probability-feedback",
 239          "Stop forward growth if the probability of best edge is less than \
 240 this threshold (in percent). Used when profile feedback is available",
 241          80)
 242 DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY,
 243          "tracer-min-branch-probability",
 244          "Stop forward growth if the probability of best edge is less than \
 245 this threshold (in percent). Used when profile feedback is not available",
 246          50)
 247
 248 /* The maximum number of incoming edges to consider for crossjumping.  */
 249 DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES,
 250          "max-crossjump-edges",
 251          "The maximum number of incoming edges to consider for crossjumping",
 252          100)
 253
 254 /* The maximum length of path considered in cse.  */
 255 DEFPARAM(PARAM_MAX_CSE_PATH_LENGTH,
 256          "max-cse-path-length",
 257          "The maximum length of path considered in cse",
 258          10)
 259
 260 #ifdef ENABLE_GC_ALWAYS_COLLECT
 261 # define GGC_MIN_EXPAND_DEFAULT 0
 262 # define GGC_MIN_HEAPSIZE_DEFAULT 0
 263 #else
 264 # define GGC_MIN_EXPAND_DEFAULT 30
 265 # define GGC_MIN_HEAPSIZE_DEFAULT 4096
 266 #endif
 267
 268 DEFPARAM(GGC_MIN_EXPAND,
 269          "ggc-min-expand",
 270          "Minimum heap expansion to trigger garbage collection, as \
 271 a percentage of the total size of the heap",
 272          GGC_MIN_EXPAND_DEFAULT)
 273
 274 DEFPARAM(GGC_MIN_HEAPSIZE,
 275          "ggc-min-heapsize",
 276          "Minimum heap size before we start collecting garbage, in kilobytes",
 277          GGC_MIN_HEAPSIZE_DEFAULT)
 278
 279 #undef GGC_MIN_EXPAND_DEFAULT
 280 #undef GGC_MIN_HEAPSIZE_DEFAULT
 281
 282 /*
 283 Local variables:
 284 mode:c
 285 End: */