Mercurial > hg > CbC > CbC_gcc
comparison gcc/predict.def @ 111:04ced10e8804
gcc 7
author | kono |
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date | Fri, 27 Oct 2017 22:46:09 +0900 |
parents | 77e2b8dfacca |
children | 84e7813d76e9 |
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68:561a7518be6b | 111:04ced10e8804 |
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1 /* Definitions for the branch prediction routines in the GNU compiler. | 1 /* Definitions for the branch prediction routines in the GNU compiler. |
2 Copyright (C) 2001, 2003, 2004, 2007, 2008 Free Software Foundation, Inc. | 2 Copyright (C) 2001-2017 Free Software Foundation, Inc. |
3 | 3 |
4 This file is part of GCC. | 4 This file is part of GCC. |
5 | 5 |
6 GCC is free software; you can redistribute it and/or modify it under | 6 GCC is free software; you can redistribute it and/or modify it under |
7 the terms of the GNU General Public License as published by the Free | 7 the terms of the GNU General Public License as published by the Free |
55 analysis to set probability. We don't want to use Dempster-Shaffer | 55 analysis to set probability. We don't want to use Dempster-Shaffer |
56 theory here, as the predictions is exact. */ | 56 theory here, as the predictions is exact. */ |
57 DEF_PREDICTOR (PRED_LOOP_ITERATIONS, "loop iterations", PROB_ALWAYS, | 57 DEF_PREDICTOR (PRED_LOOP_ITERATIONS, "loop iterations", PROB_ALWAYS, |
58 PRED_FLAG_FIRST_MATCH) | 58 PRED_FLAG_FIRST_MATCH) |
59 | 59 |
60 /* Hints dropped by user via __builtin_expect feature. */ | 60 /* Assume that any given atomic operation has low contention, |
61 and thus the compare-and-swap operation succeeds. */ | |
62 DEF_PREDICTOR (PRED_COMPARE_AND_SWAP, "compare and swap", PROB_VERY_LIKELY, | |
63 PRED_FLAG_FIRST_MATCH) | |
64 | |
65 /* Hints dropped by user via __builtin_expect feature. Note: the | |
66 probability of PROB_VERY_LIKELY is now overwritten by param | |
67 builtin_expect_probability with a default value of HITRATE(90). | |
68 Refer to param.def for details. */ | |
61 DEF_PREDICTOR (PRED_BUILTIN_EXPECT, "__builtin_expect", PROB_VERY_LIKELY, | 69 DEF_PREDICTOR (PRED_BUILTIN_EXPECT, "__builtin_expect", PROB_VERY_LIKELY, |
62 PRED_FLAG_FIRST_MATCH) | 70 PRED_FLAG_FIRST_MATCH) |
63 | 71 |
64 /* Use number of loop iterations guessed by the contents of the loop. */ | 72 /* Use number of loop iterations guessed by the contents of the loop. */ |
65 DEF_PREDICTOR (PRED_LOOP_ITERATIONS_GUESSED, "guessed loop iterations", | 73 DEF_PREDICTOR (PRED_LOOP_ITERATIONS_GUESSED, "guessed loop iterations", |
66 PROB_ALWAYS, PRED_FLAG_FIRST_MATCH) | 74 PROB_ALWAYS, PRED_FLAG_FIRST_MATCH) |
67 | 75 |
76 /* Use number of loop iterations guessed by the contents of the loop. */ | |
77 DEF_PREDICTOR (PRED_LOOP_ITERATIONS_MAX, "guessed loop iterations", | |
78 PROB_ALWAYS, PRED_FLAG_FIRST_MATCH) | |
79 | |
68 /* Branch containing goto is probably not taken. */ | 80 /* Branch containing goto is probably not taken. */ |
69 DEF_PREDICTOR (PRED_CONTINUE, "continue", HITRATE (50), 0) | 81 DEF_PREDICTOR (PRED_CONTINUE, "continue", HITRATE (67), 0) |
70 | 82 |
71 /* Branch to basic block containing call marked by noreturn attribute. */ | 83 /* Branch to basic block containing call marked by noreturn attribute. */ |
72 DEF_PREDICTOR (PRED_NORETURN, "noreturn call", PROB_VERY_LIKELY, | 84 DEF_PREDICTOR (PRED_NORETURN, "noreturn call", PROB_VERY_LIKELY, |
73 PRED_FLAG_FIRST_MATCH) | 85 PRED_FLAG_FIRST_MATCH) |
74 | 86 |
75 /* Branch to basic block containing call marked by cold function attribute. */ | 87 /* Branch to basic block containing call marked by cold function attribute. */ |
76 DEF_PREDICTOR (PRED_COLD_FUNCTION, "cold function call", PROB_VERY_LIKELY, | 88 DEF_PREDICTOR (PRED_COLD_FUNCTION, "cold function call", PROB_VERY_LIKELY, |
77 PRED_FLAG_FIRST_MATCH) | 89 PRED_FLAG_FIRST_MATCH) |
78 | 90 |
79 /* Loopback edge is taken. */ | |
80 DEF_PREDICTOR (PRED_LOOP_BRANCH, "loop branch", HITRATE (86), | |
81 PRED_FLAG_FIRST_MATCH) | |
82 | |
83 /* Edge causing loop to terminate is probably not taken. */ | 91 /* Edge causing loop to terminate is probably not taken. */ |
84 DEF_PREDICTOR (PRED_LOOP_EXIT, "loop exit", HITRATE (91), | 92 DEF_PREDICTOR (PRED_LOOP_EXIT, "loop exit", HITRATE (85), |
93 PRED_FLAG_FIRST_MATCH) | |
94 | |
95 /* Same as LOOP_EXIT but for loops containing recursive call. */ | |
96 DEF_PREDICTOR (PRED_LOOP_EXIT_WITH_RECURSION, "loop exit with recursion", | |
97 HITRATE (72), PRED_FLAG_FIRST_MATCH) | |
98 | |
99 /* Edge causing loop to terminate by computing value used by later | |
100 conditional. */ | |
101 DEF_PREDICTOR (PRED_LOOP_EXTRA_EXIT, "extra loop exit", HITRATE (83), | |
85 PRED_FLAG_FIRST_MATCH) | 102 PRED_FLAG_FIRST_MATCH) |
86 | 103 |
87 /* Pointers are usually not NULL. */ | 104 /* Pointers are usually not NULL. */ |
88 DEF_PREDICTOR (PRED_POINTER, "pointer", HITRATE (85), 0) | 105 DEF_PREDICTOR (PRED_POINTER, "pointer", HITRATE (70), 0) |
89 DEF_PREDICTOR (PRED_TREE_POINTER, "pointer (on trees)", HITRATE (85), 0) | 106 DEF_PREDICTOR (PRED_TREE_POINTER, "pointer (on trees)", HITRATE (70), 0) |
90 | 107 |
91 /* NE is probable, EQ not etc... */ | 108 /* NE is probable, EQ not etc... */ |
92 DEF_PREDICTOR (PRED_OPCODE_POSITIVE, "opcode values positive", HITRATE (79), 0) | 109 DEF_PREDICTOR (PRED_OPCODE_POSITIVE, "opcode values positive", HITRATE (64), 0) |
93 DEF_PREDICTOR (PRED_OPCODE_NONEQUAL, "opcode values nonequal", HITRATE (71), 0) | 110 DEF_PREDICTOR (PRED_OPCODE_NONEQUAL, "opcode values nonequal", HITRATE (66), 0) |
94 DEF_PREDICTOR (PRED_FPOPCODE, "fp_opcode", HITRATE (90), 0) | 111 DEF_PREDICTOR (PRED_FPOPCODE, "fp_opcode", HITRATE (90), 0) |
95 DEF_PREDICTOR (PRED_TREE_OPCODE_POSITIVE, "opcode values positive (on trees)", HITRATE (73), 0) | 112 DEF_PREDICTOR (PRED_TREE_OPCODE_POSITIVE, "opcode values positive (on trees)", |
96 DEF_PREDICTOR (PRED_TREE_OPCODE_NONEQUAL, "opcode values nonequal (on trees)", HITRATE (72), 0) | 113 HITRATE (64), 0) |
114 DEF_PREDICTOR (PRED_TREE_OPCODE_NONEQUAL, "opcode values nonequal (on trees)", | |
115 HITRATE (66), 0) | |
97 DEF_PREDICTOR (PRED_TREE_FPOPCODE, "fp_opcode (on trees)", HITRATE (90), 0) | 116 DEF_PREDICTOR (PRED_TREE_FPOPCODE, "fp_opcode (on trees)", HITRATE (90), 0) |
98 | 117 |
99 /* Branch guarding call is probably taken. */ | 118 /* Branch guarding call is probably taken. */ |
100 DEF_PREDICTOR (PRED_CALL, "call", HITRATE (71), 0) | 119 DEF_PREDICTOR (PRED_CALL, "call", HITRATE (67), 0) |
120 | |
121 /* PRED_CALL is not very reliable predictor and it turns out to be even | |
122 less reliable for indirect calls and polymorphic calls. For spec2k6 | |
123 the predictio nis slightly in the direction of taking the call. */ | |
124 DEF_PREDICTOR (PRED_INDIR_CALL, "indirect call", HITRATE (86), 0) | |
125 DEF_PREDICTOR (PRED_POLYMORPHIC_CALL, "polymorphic call", HITRATE (59), 0) | |
126 | |
127 /* Recursive calls are usually not taken or the function will recurse | |
128 indefinitely. */ | |
129 DEF_PREDICTOR (PRED_RECURSIVE_CALL, "recursive call", HITRATE (75), 0) | |
101 | 130 |
102 /* Branch causing function to terminate is probably not taken. */ | 131 /* Branch causing function to terminate is probably not taken. */ |
103 DEF_PREDICTOR (PRED_TREE_EARLY_RETURN, "early return (on trees)", HITRATE (61), 0) | 132 DEF_PREDICTOR (PRED_TREE_EARLY_RETURN, "early return (on trees)", HITRATE (66), |
133 0) | |
104 | 134 |
105 /* Branch containing goto is probably not taken. */ | 135 /* Branch containing goto is probably not taken. */ |
106 DEF_PREDICTOR (PRED_GOTO, "goto", HITRATE (70), 0) | 136 DEF_PREDICTOR (PRED_GOTO, "goto", HITRATE (66), 0) |
107 | 137 |
108 /* Branch ending with return constant is probably not taken. */ | 138 /* Branch ending with return constant is probably not taken. */ |
109 DEF_PREDICTOR (PRED_CONST_RETURN, "const return", HITRATE (67), 0) | 139 DEF_PREDICTOR (PRED_CONST_RETURN, "const return", HITRATE (69), 0) |
110 | 140 |
111 /* Branch ending with return negative constant is probably not taken. */ | 141 /* Branch ending with return negative constant is probably not taken. */ |
112 DEF_PREDICTOR (PRED_NEGATIVE_RETURN, "negative return", HITRATE (96), 0) | 142 DEF_PREDICTOR (PRED_NEGATIVE_RETURN, "negative return", HITRATE (98), 0) |
113 | 143 |
114 /* Branch ending with return; is probably not taken */ | 144 /* Branch ending with return; is probably not taken */ |
115 DEF_PREDICTOR (PRED_NULL_RETURN, "null return", HITRATE (90), 0) | 145 DEF_PREDICTOR (PRED_NULL_RETURN, "null return", HITRATE (91), 0) |
116 | 146 |
117 /* Branches to a mudflap bounds check are extremely unlikely. */ | 147 /* Branches to compare induction variable to a loop bound is |
118 DEF_PREDICTOR (PRED_MUDFLAP, "mudflap check", PROB_VERY_LIKELY, 0) | 148 extremely likely. */ |
149 DEF_PREDICTOR (PRED_LOOP_IV_COMPARE_GUESS, "guess loop iv compare", | |
150 HITRATE (98), 0) | |
151 | |
152 /* Use number of loop iterations determined by # of iterations analysis | |
153 to set probability of branches that compares IV to loop bound variable. */ | |
154 DEF_PREDICTOR (PRED_LOOP_IV_COMPARE, "loop iv compare", PROB_VERY_LIKELY, | |
155 PRED_FLAG_FIRST_MATCH) | |
156 | |
157 /* In the following code | |
158 for (loop1) | |
159 if (cond) | |
160 for (loop2) | |
161 body; | |
162 guess that cond is unlikely. */ | |
163 DEF_PREDICTOR (PRED_LOOP_GUARD, "loop guard", HITRATE (66), 0) | |
164 | |
165 /* Same but for loops containing recursion. */ | |
166 DEF_PREDICTOR (PRED_LOOP_GUARD_WITH_RECURSION, "loop guard with recursion", | |
167 HITRATE (85), 0) | |
168 | |
169 /* Branches to hot labels are likely. */ | |
170 DEF_PREDICTOR (PRED_HOT_LABEL, "hot label", HITRATE (85), 0) | |
171 | |
172 /* Branches to cold labels are extremely unlikely. */ | |
173 DEF_PREDICTOR (PRED_COLD_LABEL, "cold label", PROB_VERY_LIKELY, | |
174 PRED_FLAG_FIRST_MATCH) | |
175 | |
176 | |
177 /* The following predictors are used in Fortran. */ | |
178 | |
179 /* Branch leading to an integer overflow are extremely unlikely. */ | |
180 DEF_PREDICTOR (PRED_FORTRAN_OVERFLOW, "Fortran overflow", PROB_ALWAYS, | |
181 PRED_FLAG_FIRST_MATCH) | |
182 | |
183 /* Branch leading to a failure status are unlikely. This can occur for out | |
184 of memory. This predictor only occurs when the user explicitly asked | |
185 for a return status. By default, the code aborts, | |
186 which is handled via PRED_NORETURN. */ | |
187 DEF_PREDICTOR (PRED_FORTRAN_FAIL_ALLOC, "Fortran fail alloc", | |
188 PROB_VERY_LIKELY, 0) | |
189 | |
190 /* Predictor is used for an allocation of an already allocated memory or | |
191 deallocating an already deallocated allocatable. */ | |
192 DEF_PREDICTOR (PRED_FORTRAN_REALLOC, "Fortran repeated allocation/deallocation", | |
193 PROB_LIKELY, 0) | |
194 | |
195 /* Branch leading to an I/O failure status are unlikely. This predictor is | |
196 used for I/O failures such as for invalid unit numbers. This predictor | |
197 only occurs when the user explicitly asked for a return status. By default, | |
198 the code aborts, which is handled via PRED_NORETURN. */ | |
199 DEF_PREDICTOR (PRED_FORTRAN_FAIL_IO, "Fortran fail IO", HITRATE (85), 0) | |
200 | |
201 /* Branch leading to a run-time warning message which is printed only once | |
202 are unlikely. The print-warning branch itself can be likely or unlikely. */ | |
203 DEF_PREDICTOR (PRED_FORTRAN_WARN_ONCE, "Fortran warn once", HITRATE (75), 0) | |
204 | |
205 /* Branch belonging to a zero-sized array. */ | |
206 DEF_PREDICTOR (PRED_FORTRAN_SIZE_ZERO, "Fortran zero-sized array", \ | |
207 HITRATE (99), 0) | |
208 | |
209 /* Branch belonging to an invalid bound index, in a context where it is | |
210 standard conform and well defined but rather pointless and, hence, rather | |
211 unlikely to occur. */ | |
212 DEF_PREDICTOR (PRED_FORTRAN_INVALID_BOUND, "Fortran invalid bound", \ | |
213 HITRATE (90), 0) | |
214 | |
215 /* Branch belonging to the handling of absent optional arguments. This | |
216 predictor is used when an optional dummy argument, associated with an | |
217 absent argument, is passed on as actual argument to another procedure, | |
218 which in turn has an optional argument. */ | |
219 DEF_PREDICTOR (PRED_FORTRAN_ABSENT_DUMMY, "Fortran absent dummy", \ | |
220 HITRATE (60), 0) | |
221 | |
222 /* Fortran DO statement generates a pre-header guard: | |
223 empty = (step > 0 ? to < from : to > from), which can be predicted | |
224 to be very likely. */ | |
225 DEF_PREDICTOR (PRED_FORTRAN_LOOP_PREHEADER, "Fortran loop preheader", \ | |
226 HITRATE (99), 0) |