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1 | /* params.def - Run-time parameters. |
2 | Copyright (C) 2001 Free Software Foundation, Inc. | |
3 | Written by Mark Mitchell <mark@codesourcery.com>. | |
4 | ||
1322177d | 5 | This file is part of GCC. |
c6d9a88c | 6 | |
1322177d LB |
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. | |
c6d9a88c | 11 | |
1322177d LB |
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. | |
c6d9a88c MM |
16 | |
17 | You should have received a copy of the GNU General Public License | |
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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. | |
c6d9a88c MM |
21 | |
22 | */ | |
23 | ||
24 | /* This file contains definitions for language-independent | |
25 | parameters. The DEFPARAM macro takes 4 arguments: | |
26 | ||
0443f602 | 27 | - The enumeral corresponding to this parameter. |
c6d9a88c MM |
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 | ||
1c4c47db JO |
34 | - A default value for the parameter. |
35 | ||
36 | Be sure to add an entry to invoke.texi summarizing the parameter. */ | |
c6d9a88c | 37 | |
a6227154 KG |
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. */ | |
51 | DEFPARAM (PARAM_MAX_INLINE_INSNS_SINGLE, | |
52 | "max-inline-insns-single", | |
53 | "The maximum number of instructions in a single function eliglible for inlining", | |
54 | 300) | |
55 | ||
56 | /* The repeated inlining limit. After this number of instructions | |
57 | (in the internal gcc representation, not real machine instructions) | |
58 | got inlined by repeated inlining, gcc starts to decrease the maximum | |
59 | number of inlinable instructions in the tree inliner. | |
60 | This is done by a linear function, see "max-inline-slope" parameter. | |
61 | It is necessary in order to limit the compile-time resources, that | |
62 | could otherwise become very high. | |
63 | It is recommended to set this value to twice the value of the single | |
64 | function limit (set by the "max-inline-insns-single" parameter) or | |
65 | higher. The default value is 600. | |
66 | Higher values mean that more inlining is done, resulting in | |
67 | better performance of the code, at the expense of higher | |
68 | compile-time resource (time, memory) requirements and larger | |
69 | binaries. | |
70 | This parameters also controls the maximum size of functions considered | |
71 | for inlining in the RTL inliner. */ | |
c6d9a88c MM |
72 | DEFPARAM (PARAM_MAX_INLINE_INSNS, |
73 | "max-inline-insns", | |
a6227154 | 74 | "The maximuem number of instructions by repeated inlining before gcc starts to throttle inlining", |
eb77eeb3 | 75 | 600) |
c6d9a88c | 76 | |
a6227154 KG |
77 | /* After the repeated inline limit has been exceeded (see |
78 | "max-inline-insns" parameter), a linear function is used to | |
79 | decrease the size of single functions eligible for inlining. | |
80 | The slope of this linear function is given the negative | |
81 | reciprocal value (-1/x) of this parameter. | |
82 | The default vlue is 32. | |
83 | This linear function is used until it falls below a minimum | |
84 | value specified by the "min-inline-insns" parameter. */ | |
85 | DEFPARAM (PARAM_MAX_INLINE_SLOPE, | |
86 | "max-inline-slope", | |
87 | "The slope of the linear funtion throttling inlining after the recursive inlining limit has been reached is given by the negative reciprocal value of this parameter", | |
88 | 32) | |
89 | ||
90 | /* When gcc has inlined so many instructions (by repeated | |
91 | inlining) that the throttling limits the inlining very much, | |
92 | inlining for very small functions is still desirable to | |
93 | achieve good runtime performance. The size of single functions | |
94 | (measured in gcc instructions) which will still be eligible for | |
95 | inlining then is given by this parameter. It defaults to 130. | |
96 | Only much later (after exceeding 128 times the recursive limit) | |
97 | inlining is cut down completely. */ | |
98 | DEFPARAM (PARAM_MIN_INLINE_INSNS, | |
99 | "min-inline-insns", | |
100 | "The number of instructions in a single functions still eligible to inlining after a lot recursive inlining", | |
101 | 130) | |
102 | ||
0443f602 JO |
103 | /* The maximum number of instructions to consider when looking for an |
104 | instruction to fill a delay slot. If more than this arbitrary | |
105 | number of instructions is searched, the time savings from filling | |
106 | the delay slot will be minimal so stop searching. Increasing | |
107 | values mean more aggressive optimization, making the compile time | |
108 | increase with probably small improvement in executable run time. */ | |
109 | DEFPARAM (PARAM_MAX_DELAY_SLOT_INSN_SEARCH, | |
110 | "max-delay-slot-insn-search", | |
111 | "The maximum number of instructions to consider to fill a delay slot", | |
112 | 100) | |
113 | ||
d5d063d7 JO |
114 | /* When trying to fill delay slots, the maximum number of instructions |
115 | to consider when searching for a block with valid live register | |
116 | information. Increasing this arbitrarily chosen value means more | |
117 | aggressive optimization, increasing the compile time. This | |
118 | parameter should be removed when the delay slot code is rewritten | |
119 | to maintain the control-flow graph. */ | |
120 | DEFPARAM(PARAM_MAX_DELAY_SLOT_LIVE_SEARCH, | |
121 | "max-delay-slot-live-search", | |
122 | "The maximum number of instructions to consider to find accurate live register information", | |
123 | 333) | |
124 | ||
4a121cc3 | 125 | /* This parameter limits the number of branch elements that the |
ff7cc307 | 126 | scheduler will track anti-dependencies through without resetting |
4a121cc3 | 127 | the tracking mechanism. Large functions with few calls or barriers |
ff7cc307 | 128 | can generate lists containing many 1000's of dependencies. Generally |
4a121cc3 AM |
129 | the compiler either uses all available memory, or runs for far too long. */ |
130 | DEFPARAM(PARAM_MAX_PENDING_LIST_LENGTH, | |
131 | "max-pending-list-length", | |
132 | "The maximum length of scheduling's pending operations list", | |
133 | 32) | |
134 | ||
f1fa37ff MM |
135 | /* The GCSE optimization will be disabled if it would require |
136 | significantly more memory than this value. */ | |
137 | DEFPARAM(PARAM_MAX_GCSE_MEMORY, | |
138 | "max-gcse-memory", | |
139 | "The maximum amount of memory to be allocated by GCSE", | |
140 | 50 * 1024 * 1024) | |
991b6592 | 141 | /* The number of repetitions of copy/const prop and PRE to run. */ |
740f35a0 DB |
142 | DEFPARAM(PARAM_MAX_GCSE_PASSES, |
143 | "max-gcse-passes", | |
144 | "The maximum number of passes to make when doing GCSE", | |
145 | 1) | |
03e9dbc9 MM |
146 | |
147 | /* This parameter limits the number of insns in a loop that will be unrolled, | |
148 | and by how much the loop is unrolled. */ | |
149 | DEFPARAM(PARAM_MAX_UNROLLED_INSNS, | |
150 | "max-unrolled-insns", | |
151 | "The maximum number of instructions to consider to unroll in a loop", | |
152 | 100) | |
194734e9 JH |
153 | |
154 | DEFPARAM(HOT_BB_COUNT_FRACTION, | |
155 | "hot-bb-count-fraction", | |
5c856b23 JH |
156 | "Select fraction of the maximal count of repetitions of basic block in \ |
157 | program given basic block needs to have to be considered hot", | |
194734e9 JH |
158 | 10000) |
159 | DEFPARAM(HOT_BB_FREQUENCY_FRACTION, | |
160 | "hot-bb-frequency-fraction", | |
5c856b23 JH |
161 | "Select fraction of the maximal frequency of executions of basic \ |
162 | block in function given basic block needs to have to be considered hot", | |
194734e9 | 163 | 1000) |
5c856b23 JH |
164 | DEFPARAM(TRACER_DYNAMIC_COVERAGE_FEEDBACK, |
165 | "tracer-dynamic-coverage-feedback", | |
166 | "The percentage of function, weighted by execution frequency, that \ | |
167 | must be covered by trace formation. Used when profile feedback is available", | |
168 | 95) | |
169 | DEFPARAM(TRACER_DYNAMIC_COVERAGE, | |
170 | "tracer-dynamic-coverage", | |
171 | "The percentage of function, weighted by execution frequency, that \ | |
172 | must be covered by trace formation. Used when profile feedback is not available", | |
173 | 75) | |
174 | DEFPARAM(TRACER_MAX_CODE_GROWTH, | |
175 | "tracer-max-code-growth", | |
176 | "Maximal code growth caused by tail duplication (in percents)", | |
177 | 100) | |
178 | DEFPARAM(TRACER_MIN_BRANCH_RATIO, | |
179 | "tracer-min-branch-ratio", | |
180 | "Stop reverse growth if the reverse probability of best edge is less \ | |
181 | than this threshold (in percents)", | |
182 | 10) | |
183 | DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY_FEEDBACK, | |
184 | "tracer-min-branch-probability-feedback", | |
185 | "Stop forward growth if the probability of best edge is less than \ | |
186 | this threshold (in percents). Used when profile feedback is available", | |
187 | 30) | |
188 | DEFPARAM(TRACER_MIN_BRANCH_PROBABILITY, | |
189 | "tracer-min-branch-probability", | |
190 | "Stop forward growth if the probability of best edge is less than \ | |
191 | this threshold (in percents). Used when profile feedback is not available", | |
192 | 50) | |
c6d9a88c MM |
193 | /* |
194 | Local variables: | |
195 | mode:c | |
196 | End: */ |