params.def revision 117395
1/* params.def - Run-time parameters. 2 Copyright (C) 2001, 2002 Free Software Foundation, Inc. 3 Written by Mark Mitchell <mark@codesourcery.com>. 4 5This file is part of GCC. 6 7GCC is free software; you can redistribute it and/or modify it under 8the terms of the GNU General Public License as published by the Free 9Software Foundation; either version 2, or (at your option) any later 10version. 11 12GCC is distributed in the hope that it will be useful, but WITHOUT ANY 13WARRANTY; without even the implied warranty of MERCHANTABILITY or 14FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 15for more details. 16 17You should have received a copy of the GNU General Public License 18along with GCC; see the file COPYING. If not, write to the Free 19Software Foundation, 59 Temple Place - Suite 330, Boston, MA 2002111-1307, 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 300. 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. */ 51DEFPARAM (PARAM_MAX_INLINE_INSNS_SINGLE, 52 "max-inline-insns-single", 53 "The maximum number of instructions in a single function eligible for inlining", 54 300) 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 300. */ 63DEFPARAM (PARAM_MAX_INLINE_INSNS_AUTO, 64 "max-inline-insns-auto", 65 "The maximum number of instructions when automatically inlining", 66 300) 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 600. 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. */ 82DEFPARAM (PARAM_MAX_INLINE_INSNS, 83 "max-inline-insns", 84 "The maximum number of instructions by repeated inlining before gcc starts to throttle inlining", 85 600) 86 87/* After the repeated inline limit has been exceeded (see 88 "max-inline-insns" parameter), a linear function is used to 89 decrease the size of single functions eligible for inlining. 90 The slope of this linear function is given the negative 91 reciprocal value (-1/x) of this parameter. 92 The default value is 32. 93 This linear function is used until it falls below a minimum 94 value specified by the "min-inline-insns" parameter. */ 95DEFPARAM (PARAM_MAX_INLINE_SLOPE, 96 "max-inline-slope", 97 "The slope of the linear function throttling inlining after the recursive inlining limit has been reached is given by the negative reciprocal value of this parameter", 98 32) 99 100/* When gcc has inlined so many instructions (by repeated 101 inlining) that the throttling limits the inlining very much, 102 inlining for very small functions is still desirable to 103 achieve good runtime performance. The size of single functions 104 (measured in gcc instructions) which will still be eligible for 105 inlining then is given by this parameter. It defaults to 130. 106 Only much later (after exceeding 128 times the recursive limit) 107 inlining is cut down completely. */ 108DEFPARAM (PARAM_MIN_INLINE_INSNS, 109 "min-inline-insns", 110 "The number of instructions in a single functions still eligible to inlining after a lot recursive inlining", 111 130) 112 113/* For languages that (still) use the RTL inliner, we can specify 114 limits for the RTL inliner separately. 115 The parameter here defines the maximum number of RTL instructions 116 a function may have to be eligible for inlining in the RTL inliner. 117 The default value is 600. */ 118DEFPARAM (PARAM_MAX_INLINE_INSNS_RTL, 119 "max-inline-insns-rtl", 120 "The maximum number of instructions for the RTL inliner", 121 600) 122 123/* The maximum number of instructions to consider when looking for an 124 instruction to fill a delay slot. If more than this arbitrary 125 number of instructions is searched, the time savings from filling 126 the delay slot will be minimal so stop searching. Increasing 127 values mean more aggressive optimization, making the compile time 128 increase with probably small improvement in executable run time. */ 129DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH, 130 "max-delay-slot-insn-search", 131 "The maximum number of instructions to consider to fill a delay slot", 132 100) 133 134/* When trying to fill delay slots, the maximum number of instructions 135 to consider when searching for a block with valid live register 136 information. Increasing this arbitrarily chosen value means more 137 aggressive optimization, increasing the compile time. This 138 parameter should be removed when the delay slot code is rewritten 139 to maintain the control-flow graph. */ 140DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH, 141 "max-delay-slot-live-search", 142 "The maximum number of instructions to consider to find accurate live register information", 143 333) 144 145/* This parameter limits the number of branch elements that the 146 scheduler will track anti-dependencies through without resetting 147 the tracking mechanism. Large functions with few calls or barriers 148 can generate lists containing many 1000's of dependencies. Generally 149 the compiler either uses all available memory, or runs for far too long. */ 150DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH, 151 "max-pending-list-length", 152 "The maximum length of scheduling's pending operations list", 153 32) 154 155/* The GCSE optimization will be disabled if it would require 156 significantly more memory than this value. */ 157DEFPARAM(PARAM_MAX_GCSE_MEMORY, 158 "max-gcse-memory", 159 "The maximum amount of memory to be allocated by GCSE", 160 50 * 1024 * 1024) 161/* The number of repetitions of copy/const prop and PRE to run. */ 162DEFPARAM(PARAM_MAX_GCSE_PASSES, 163 "max-gcse-passes", 164 "The maximum number of passes to make when doing GCSE", 165 1) 166 167/* This parameter limits the number of insns in a loop that will be unrolled, 168 and by how much the loop is unrolled. */ 169DEFPARAM(PARAM_MAX_UNROLLED_INSNS, 170 "max-unrolled-insns", 171 "The maximum number of instructions to consider to unroll in a loop", 172 100) 173 174DEFPARAM(HOT_BB_COUNT_FRACTION, 175 "hot-bb-count-fraction", 176 "Select fraction of the maximal count of repetitions of basic block in \ 177program given basic block needs to have to be considered hot", 178 10000) 179DEFPARAM(HOT_BB_FREQUENCY_FRACTION, 180 "hot-bb-frequency-fraction", 181 "Select fraction of the maximal frequency of executions of basic \ 182block in function given basic block needs to have to be considered hot", 183 1000) 184DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK, 185 "tracer-dynamic-coverage-feedback", 186 "The percentage of function, weighted by execution frequency, that \ 187must be covered by trace formation. Used when profile feedback is available", 188 95) 189DEFPARAM(TRACER_DYNAMIC_COVERAGE, 190 "tracer-dynamic-coverage", 191 "The percentage of function, weighted by execution frequency, that \ 192must be covered by trace formation. Used when profile feedback is not available", 193 75) 194DEFPARAM(TRACER_MAX_CODE_GROWTH, 195 "tracer-max-code-growth", 196 "Maximal code growth caused by tail duplication (in percents)", 197 100) 198DEFPARAM(TRACER_MIN_BRANCH_RATIO, 199 "tracer-min-branch-ratio", 200 "Stop reverse growth if the reverse probability of best edge is less \ 201than this threshold (in percents)", 202 10) 203DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK, 204 "tracer-min-branch-probability-feedback", 205 "Stop forward growth if the probability of best edge is less than \ 206this threshold (in percents). Used when profile feedback is available", 207 30) 208DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY, 209 "tracer-min-branch-probability", 210 "Stop forward growth if the probability of best edge is less than \ 211this threshold (in percents). Used when profile feedback is not available", 212 50) 213 214/* The maximum number of incoming edges to consider for crossjumping. */ 215DEFPARAM(PARAM_MAX_CROSSJUMP_EDGES, 216 "max-crossjump-edges", 217 "The maximum number of incoming edges to consider for crossjumping", 218 100) 219 220#ifdef ENABLE_GC_ALWAYS_COLLECT 221# define GGC_MIN_EXPAND_DEFAULT 0 222# define GGC_MIN_HEAPSIZE_DEFAULT 0 223#else 224# define GGC_MIN_EXPAND_DEFAULT 30 225# define GGC_MIN_HEAPSIZE_DEFAULT 4096 226#endif 227 228DEFPARAM(GGC_MIN_EXPAND, 229 "ggc-min-expand", 230 "Minimum heap expansion to trigger garbage collection, as \ 231a percentage of the total size of the heap.", 232 GGC_MIN_EXPAND_DEFAULT) 233 234DEFPARAM(GGC_MIN_HEAPSIZE, 235 "ggc-min-heapsize", 236 "Minimum heap size before we start collecting garbage, in kilobytes.", 237 GGC_MIN_HEAPSIZE_DEFAULT) 238 239#undef GGC_MIN_EXPAND_DEFAULT 240#undef GGC_MIN_HEAPSIZE_DEFAULT 241 242/* 243Local variables: 244mode:c 245End: */ 246