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0
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1 /* Basic block reordering routines for the GNU compiler.
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2 Copyright (C) 2000, 2002, 2003, 2004, 2005, 2006, 2007, 2008
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3 Free Software Foundation, Inc.
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4
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5 This file is part of GCC.
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6
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7 GCC is free software; you can redistribute it and/or modify it
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8 under the terms of the GNU General Public License as published by
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9 the Free Software Foundation; either version 3, or (at your option)
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10 any later version.
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11
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12 GCC is distributed in the hope that it will be useful, but WITHOUT
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13 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
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15 License for more details.
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16
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17 You should have received a copy of the GNU General Public License
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18 along with GCC; see the file COPYING3. If not see
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19 <http://www.gnu.org/licenses/>. */
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20
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21 /* This (greedy) algorithm constructs traces in several rounds.
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22 The construction starts from "seeds". The seed for the first round
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23 is the entry point of function. When there are more than one seed
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24 that one is selected first that has the lowest key in the heap
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25 (see function bb_to_key). Then the algorithm repeatedly adds the most
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26 probable successor to the end of a trace. Finally it connects the traces.
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27
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28 There are two parameters: Branch Threshold and Exec Threshold.
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29 If the edge to a successor of the actual basic block is lower than
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30 Branch Threshold or the frequency of the successor is lower than
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31 Exec Threshold the successor will be the seed in one of the next rounds.
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32 Each round has these parameters lower than the previous one.
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33 The last round has to have these parameters set to zero
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34 so that the remaining blocks are picked up.
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35
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36 The algorithm selects the most probable successor from all unvisited
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37 successors and successors that have been added to this trace.
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38 The other successors (that has not been "sent" to the next round) will be
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39 other seeds for this round and the secondary traces will start in them.
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40 If the successor has not been visited in this trace it is added to the trace
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41 (however, there is some heuristic for simple branches).
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42 If the successor has been visited in this trace the loop has been found.
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43 If the loop has many iterations the loop is rotated so that the
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44 source block of the most probable edge going out from the loop
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45 is the last block of the trace.
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46 If the loop has few iterations and there is no edge from the last block of
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47 the loop going out from loop the loop header is duplicated.
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48 Finally, the construction of the trace is terminated.
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49
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50 When connecting traces it first checks whether there is an edge from the
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51 last block of one trace to the first block of another trace.
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52 When there are still some unconnected traces it checks whether there exists
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53 a basic block BB such that BB is a successor of the last bb of one trace
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54 and BB is a predecessor of the first block of another trace. In this case,
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55 BB is duplicated and the traces are connected through this duplicate.
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56 The rest of traces are simply connected so there will be a jump to the
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57 beginning of the rest of trace.
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58
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59
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60 References:
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61
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62 "Software Trace Cache"
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63 A. Ramirez, J. Larriba-Pey, C. Navarro, J. Torrellas and M. Valero; 1999
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64 http://citeseer.nj.nec.com/15361.html
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65
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66 */
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67
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68 #include "config.h"
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69 #include "system.h"
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70 #include "coretypes.h"
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71 #include "tm.h"
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72 #include "rtl.h"
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73 #include "regs.h"
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74 #include "flags.h"
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75 #include "timevar.h"
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76 #include "output.h"
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77 #include "cfglayout.h"
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78 #include "fibheap.h"
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79 #include "target.h"
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80 #include "function.h"
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81 #include "tm_p.h"
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82 #include "obstack.h"
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83 #include "expr.h"
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84 #include "params.h"
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85 #include "toplev.h"
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86 #include "tree-pass.h"
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87 #include "df.h"
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88
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89 #ifndef HAVE_conditional_execution
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90 #define HAVE_conditional_execution 0
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91 #endif
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92
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93 /* The number of rounds. In most cases there will only be 4 rounds, but
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94 when partitioning hot and cold basic blocks into separate sections of
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95 the .o file there will be an extra round.*/
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96 #define N_ROUNDS 5
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97
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98 /* Stubs in case we don't have a return insn.
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99 We have to check at runtime too, not only compiletime. */
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100
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101 #ifndef HAVE_return
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102 #define HAVE_return 0
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103 #define gen_return() NULL_RTX
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104 #endif
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105
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106
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107 /* Branch thresholds in thousandths (per mille) of the REG_BR_PROB_BASE. */
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108 static int branch_threshold[N_ROUNDS] = {400, 200, 100, 0, 0};
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109
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110 /* Exec thresholds in thousandths (per mille) of the frequency of bb 0. */
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111 static int exec_threshold[N_ROUNDS] = {500, 200, 50, 0, 0};
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112
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113 /* If edge frequency is lower than DUPLICATION_THRESHOLD per mille of entry
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114 block the edge destination is not duplicated while connecting traces. */
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115 #define DUPLICATION_THRESHOLD 100
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116
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117 /* Length of unconditional jump instruction. */
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118 static int uncond_jump_length;
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119
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120 /* Structure to hold needed information for each basic block. */
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121 typedef struct bbro_basic_block_data_def
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122 {
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123 /* Which trace is the bb start of (-1 means it is not a start of a trace). */
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124 int start_of_trace;
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125
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126 /* Which trace is the bb end of (-1 means it is not an end of a trace). */
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127 int end_of_trace;
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128
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129 /* Which trace is the bb in? */
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130 int in_trace;
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131
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132 /* Which heap is BB in (if any)? */
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133 fibheap_t heap;
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134
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135 /* Which heap node is BB in (if any)? */
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136 fibnode_t node;
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137 } bbro_basic_block_data;
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138
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139 /* The current size of the following dynamic array. */
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140 static int array_size;
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141
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142 /* The array which holds needed information for basic blocks. */
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143 static bbro_basic_block_data *bbd;
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144
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145 /* To avoid frequent reallocation the size of arrays is greater than needed,
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146 the number of elements is (not less than) 1.25 * size_wanted. */
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147 #define GET_ARRAY_SIZE(X) ((((X) / 4) + 1) * 5)
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148
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149 /* Free the memory and set the pointer to NULL. */
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150 #define FREE(P) (gcc_assert (P), free (P), P = 0)
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151
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152 /* Structure for holding information about a trace. */
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153 struct trace
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154 {
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155 /* First and last basic block of the trace. */
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156 basic_block first, last;
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157
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158 /* The round of the STC creation which this trace was found in. */
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159 int round;
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160
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161 /* The length (i.e. the number of basic blocks) of the trace. */
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162 int length;
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163 };
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164
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165 /* Maximum frequency and count of one of the entry blocks. */
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166 static int max_entry_frequency;
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167 static gcov_type max_entry_count;
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168
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169 /* Local function prototypes. */
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170 static void find_traces (int *, struct trace *);
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171 static basic_block rotate_loop (edge, struct trace *, int);
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172 static void mark_bb_visited (basic_block, int);
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173 static void find_traces_1_round (int, int, gcov_type, struct trace *, int *,
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174 int, fibheap_t *, int);
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175 static basic_block copy_bb (basic_block, edge, basic_block, int);
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176 static fibheapkey_t bb_to_key (basic_block);
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177 static bool better_edge_p (const_basic_block, const_edge, int, int, int, int, const_edge);
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178 static void connect_traces (int, struct trace *);
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179 static bool copy_bb_p (const_basic_block, int);
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180 static int get_uncond_jump_length (void);
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181 static bool push_to_next_round_p (const_basic_block, int, int, int, gcov_type);
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182 static void find_rarely_executed_basic_blocks_and_crossing_edges (edge **,
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183 int *,
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184 int *);
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185 static void add_labels_and_missing_jumps (edge *, int);
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186 static void add_reg_crossing_jump_notes (void);
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187 static void fix_up_fall_thru_edges (void);
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188 static void fix_edges_for_rarely_executed_code (edge *, int);
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189 static void fix_crossing_conditional_branches (void);
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190 static void fix_crossing_unconditional_branches (void);
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191
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192 /* Check to see if bb should be pushed into the next round of trace
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193 collections or not. Reasons for pushing the block forward are 1).
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194 If the block is cold, we are doing partitioning, and there will be
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195 another round (cold partition blocks are not supposed to be
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196 collected into traces until the very last round); or 2). There will
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197 be another round, and the basic block is not "hot enough" for the
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198 current round of trace collection. */
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199
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200 static bool
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201 push_to_next_round_p (const_basic_block bb, int round, int number_of_rounds,
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202 int exec_th, gcov_type count_th)
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203 {
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204 bool there_exists_another_round;
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205 bool block_not_hot_enough;
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206
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207 there_exists_another_round = round < number_of_rounds - 1;
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208
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209 block_not_hot_enough = (bb->frequency < exec_th
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210 || bb->count < count_th
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211 || probably_never_executed_bb_p (bb));
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212
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213 if (there_exists_another_round
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214 && block_not_hot_enough)
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215 return true;
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216 else
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217 return false;
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218 }
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219
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220 /* Find the traces for Software Trace Cache. Chain each trace through
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221 RBI()->next. Store the number of traces to N_TRACES and description of
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222 traces to TRACES. */
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223
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224 static void
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225 find_traces (int *n_traces, struct trace *traces)
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226 {
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227 int i;
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228 int number_of_rounds;
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229 edge e;
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230 edge_iterator ei;
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231 fibheap_t heap;
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232
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233 /* Add one extra round of trace collection when partitioning hot/cold
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234 basic blocks into separate sections. The last round is for all the
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235 cold blocks (and ONLY the cold blocks). */
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236
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237 number_of_rounds = N_ROUNDS - 1;
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238
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239 /* Insert entry points of function into heap. */
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240 heap = fibheap_new ();
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241 max_entry_frequency = 0;
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242 max_entry_count = 0;
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243 FOR_EACH_EDGE (e, ei, ENTRY_BLOCK_PTR->succs)
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244 {
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245 bbd[e->dest->index].heap = heap;
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246 bbd[e->dest->index].node = fibheap_insert (heap, bb_to_key (e->dest),
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247 e->dest);
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248 if (e->dest->frequency > max_entry_frequency)
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249 max_entry_frequency = e->dest->frequency;
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250 if (e->dest->count > max_entry_count)
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251 max_entry_count = e->dest->count;
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252 }
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253
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254 /* Find the traces. */
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255 for (i = 0; i < number_of_rounds; i++)
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256 {
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257 gcov_type count_threshold;
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258
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259 if (dump_file)
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260 fprintf (dump_file, "STC - round %d\n", i + 1);
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261
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262 if (max_entry_count < INT_MAX / 1000)
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263 count_threshold = max_entry_count * exec_threshold[i] / 1000;
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264 else
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265 count_threshold = max_entry_count / 1000 * exec_threshold[i];
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266
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267 find_traces_1_round (REG_BR_PROB_BASE * branch_threshold[i] / 1000,
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268 max_entry_frequency * exec_threshold[i] / 1000,
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269 count_threshold, traces, n_traces, i, &heap,
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270 number_of_rounds);
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271 }
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272 fibheap_delete (heap);
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273
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274 if (dump_file)
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275 {
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276 for (i = 0; i < *n_traces; i++)
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277 {
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278 basic_block bb;
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279 fprintf (dump_file, "Trace %d (round %d): ", i + 1,
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280 traces[i].round + 1);
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281 for (bb = traces[i].first; bb != traces[i].last; bb = (basic_block) bb->aux)
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282 fprintf (dump_file, "%d [%d] ", bb->index, bb->frequency);
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283 fprintf (dump_file, "%d [%d]\n", bb->index, bb->frequency);
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284 }
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285 fflush (dump_file);
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286 }
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287 }
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288
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289 /* Rotate loop whose back edge is BACK_EDGE in the tail of trace TRACE
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290 (with sequential number TRACE_N). */
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291
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292 static basic_block
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293 rotate_loop (edge back_edge, struct trace *trace, int trace_n)
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294 {
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295 basic_block bb;
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296
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297 /* Information about the best end (end after rotation) of the loop. */
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298 basic_block best_bb = NULL;
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299 edge best_edge = NULL;
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300 int best_freq = -1;
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301 gcov_type best_count = -1;
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302 /* The best edge is preferred when its destination is not visited yet
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303 or is a start block of some trace. */
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304 bool is_preferred = false;
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305
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306 /* Find the most frequent edge that goes out from current trace. */
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307 bb = back_edge->dest;
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308 do
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309 {
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310 edge e;
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311 edge_iterator ei;
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312
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313 FOR_EACH_EDGE (e, ei, bb->succs)
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314 if (e->dest != EXIT_BLOCK_PTR
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315 && e->dest->il.rtl->visited != trace_n
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316 && (e->flags & EDGE_CAN_FALLTHRU)
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317 && !(e->flags & EDGE_COMPLEX))
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318 {
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319 if (is_preferred)
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320 {
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321 /* The best edge is preferred. */
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322 if (!e->dest->il.rtl->visited
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323 || bbd[e->dest->index].start_of_trace >= 0)
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324 {
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325 /* The current edge E is also preferred. */
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326 int freq = EDGE_FREQUENCY (e);
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327 if (freq > best_freq || e->count > best_count)
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328 {
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329 best_freq = freq;
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330 best_count = e->count;
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331 best_edge = e;
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332 best_bb = bb;
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333 }
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334 }
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335 }
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336 else
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337 {
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338 if (!e->dest->il.rtl->visited
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339 || bbd[e->dest->index].start_of_trace >= 0)
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340 {
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341 /* The current edge E is preferred. */
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342 is_preferred = true;
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343 best_freq = EDGE_FREQUENCY (e);
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344 best_count = e->count;
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345 best_edge = e;
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346 best_bb = bb;
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347 }
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348 else
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349 {
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350 int freq = EDGE_FREQUENCY (e);
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351 if (!best_edge || freq > best_freq || e->count > best_count)
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352 {
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353 best_freq = freq;
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354 best_count = e->count;
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355 best_edge = e;
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356 best_bb = bb;
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357 }
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358 }
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359 }
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360 }
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361 bb = (basic_block) bb->aux;
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362 }
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363 while (bb != back_edge->dest);
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364
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365 if (best_bb)
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366 {
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367 /* Rotate the loop so that the BEST_EDGE goes out from the last block of
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368 the trace. */
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369 if (back_edge->dest == trace->first)
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370 {
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371 trace->first = (basic_block) best_bb->aux;
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372 }
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373 else
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374 {
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375 basic_block prev_bb;
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376
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377 for (prev_bb = trace->first;
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378 prev_bb->aux != back_edge->dest;
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379 prev_bb = (basic_block) prev_bb->aux)
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380 ;
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381 prev_bb->aux = best_bb->aux;
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382
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383 /* Try to get rid of uncond jump to cond jump. */
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384 if (single_succ_p (prev_bb))
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385 {
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386 basic_block header = single_succ (prev_bb);
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387
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388 /* Duplicate HEADER if it is a small block containing cond jump
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389 in the end. */
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390 if (any_condjump_p (BB_END (header)) && copy_bb_p (header, 0)
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391 && !find_reg_note (BB_END (header), REG_CROSSING_JUMP,
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392 NULL_RTX))
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393 copy_bb (header, single_succ_edge (prev_bb), prev_bb, trace_n);
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394 }
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395 }
|
|
|
396 }
|
|
|
397 else
|
|
|
398 {
|
|
|
399 /* We have not found suitable loop tail so do no rotation. */
|
|
|
400 best_bb = back_edge->src;
|
|
|
401 }
|
|
|
402 best_bb->aux = NULL;
|
|
|
403 return best_bb;
|
|
|
404 }
|
|
|
405
|
|
|
406 /* This function marks BB that it was visited in trace number TRACE. */
|
|
|
407
|
|
|
408 static void
|
|
|
409 mark_bb_visited (basic_block bb, int trace)
|
|
|
410 {
|
|
|
411 bb->il.rtl->visited = trace;
|
|
|
412 if (bbd[bb->index].heap)
|
|
|
413 {
|
|
|
414 fibheap_delete_node (bbd[bb->index].heap, bbd[bb->index].node);
|
|
|
415 bbd[bb->index].heap = NULL;
|
|
|
416 bbd[bb->index].node = NULL;
|
|
|
417 }
|
|
|
418 }
|
|
|
419
|
|
|
420 /* One round of finding traces. Find traces for BRANCH_TH and EXEC_TH i.e. do
|
|
|
421 not include basic blocks their probability is lower than BRANCH_TH or their
|
|
|
422 frequency is lower than EXEC_TH into traces (or count is lower than
|
|
|
423 COUNT_TH). It stores the new traces into TRACES and modifies the number of
|
|
|
424 traces *N_TRACES. Sets the round (which the trace belongs to) to ROUND. It
|
|
|
425 expects that starting basic blocks are in *HEAP and at the end it deletes
|
|
|
426 *HEAP and stores starting points for the next round into new *HEAP. */
|
|
|
427
|
|
|
428 static void
|
|
|
429 find_traces_1_round (int branch_th, int exec_th, gcov_type count_th,
|
|
|
430 struct trace *traces, int *n_traces, int round,
|
|
|
431 fibheap_t *heap, int number_of_rounds)
|
|
|
432 {
|
|
|
433 /* Heap for discarded basic blocks which are possible starting points for
|
|
|
434 the next round. */
|
|
|
435 fibheap_t new_heap = fibheap_new ();
|
|
|
436
|
|
|
437 while (!fibheap_empty (*heap))
|
|
|
438 {
|
|
|
439 basic_block bb;
|
|
|
440 struct trace *trace;
|
|
|
441 edge best_edge, e;
|
|
|
442 fibheapkey_t key;
|
|
|
443 edge_iterator ei;
|
|
|
444
|
|
|
445 bb = (basic_block) fibheap_extract_min (*heap);
|
|
|
446 bbd[bb->index].heap = NULL;
|
|
|
447 bbd[bb->index].node = NULL;
|
|
|
448
|
|
|
449 if (dump_file)
|
|
|
450 fprintf (dump_file, "Getting bb %d\n", bb->index);
|
|
|
451
|
|
|
452 /* If the BB's frequency is too low send BB to the next round. When
|
|
|
453 partitioning hot/cold blocks into separate sections, make sure all
|
|
|
454 the cold blocks (and ONLY the cold blocks) go into the (extra) final
|
|
|
455 round. */
|
|
|
456
|
|
|
457 if (push_to_next_round_p (bb, round, number_of_rounds, exec_th,
|
|
|
458 count_th))
|
|
|
459 {
|
|
|
460 int key = bb_to_key (bb);
|
|
|
461 bbd[bb->index].heap = new_heap;
|
|
|
462 bbd[bb->index].node = fibheap_insert (new_heap, key, bb);
|
|
|
463
|
|
|
464 if (dump_file)
|
|
|
465 fprintf (dump_file,
|
|
|
466 " Possible start point of next round: %d (key: %d)\n",
|
|
|
467 bb->index, key);
|
|
|
468 continue;
|
|
|
469 }
|
|
|
470
|
|
|
471 trace = traces + *n_traces;
|
|
|
472 trace->first = bb;
|
|
|
473 trace->round = round;
|
|
|
474 trace->length = 0;
|
|
|
475 bbd[bb->index].in_trace = *n_traces;
|
|
|
476 (*n_traces)++;
|
|
|
477
|
|
|
478 do
|
|
|
479 {
|
|
|
480 int prob, freq;
|
|
|
481 bool ends_in_call;
|
|
|
482
|
|
|
483 /* The probability and frequency of the best edge. */
|
|
|
484 int best_prob = INT_MIN / 2;
|
|
|
485 int best_freq = INT_MIN / 2;
|
|
|
486
|
|
|
487 best_edge = NULL;
|
|
|
488 mark_bb_visited (bb, *n_traces);
|
|
|
489 trace->length++;
|
|
|
490
|
|
|
491 if (dump_file)
|
|
|
492 fprintf (dump_file, "Basic block %d was visited in trace %d\n",
|
|
|
493 bb->index, *n_traces - 1);
|
|
|
494
|
|
|
495 ends_in_call = block_ends_with_call_p (bb);
|
|
|
496
|
|
|
497 /* Select the successor that will be placed after BB. */
|
|
|
498 FOR_EACH_EDGE (e, ei, bb->succs)
|
|
|
499 {
|
|
|
500 gcc_assert (!(e->flags & EDGE_FAKE));
|
|
|
501
|
|
|
502 if (e->dest == EXIT_BLOCK_PTR)
|
|
|
503 continue;
|
|
|
504
|
|
|
505 if (e->dest->il.rtl->visited
|
|
|
506 && e->dest->il.rtl->visited != *n_traces)
|
|
|
507 continue;
|
|
|
508
|
|
|
509 if (BB_PARTITION (e->dest) != BB_PARTITION (bb))
|
|
|
510 continue;
|
|
|
511
|
|
|
512 prob = e->probability;
|
|
|
513 freq = e->dest->frequency;
|
|
|
514
|
|
|
515 /* The only sensible preference for a call instruction is the
|
|
|
516 fallthru edge. Don't bother selecting anything else. */
|
|
|
517 if (ends_in_call)
|
|
|
518 {
|
|
|
519 if (e->flags & EDGE_CAN_FALLTHRU)
|
|
|
520 {
|
|
|
521 best_edge = e;
|
|
|
522 best_prob = prob;
|
|
|
523 best_freq = freq;
|
|
|
524 }
|
|
|
525 continue;
|
|
|
526 }
|
|
|
527
|
|
|
528 /* Edge that cannot be fallthru or improbable or infrequent
|
|
|
529 successor (i.e. it is unsuitable successor). */
|
|
|
530 if (!(e->flags & EDGE_CAN_FALLTHRU) || (e->flags & EDGE_COMPLEX)
|
|
|
531 || prob < branch_th || EDGE_FREQUENCY (e) < exec_th
|
|
|
532 || e->count < count_th)
|
|
|
533 continue;
|
|
|
534
|
|
|
535 /* If partitioning hot/cold basic blocks, don't consider edges
|
|
|
536 that cross section boundaries. */
|
|
|
537
|
|
|
538 if (better_edge_p (bb, e, prob, freq, best_prob, best_freq,
|
|
|
539 best_edge))
|
|
|
540 {
|
|
|
541 best_edge = e;
|
|
|
542 best_prob = prob;
|
|
|
543 best_freq = freq;
|
|
|
544 }
|
|
|
545 }
|
|
|
546
|
|
|
547 /* If the best destination has multiple predecessors, and can be
|
|
|
548 duplicated cheaper than a jump, don't allow it to be added
|
|
|
549 to a trace. We'll duplicate it when connecting traces. */
|
|
|
550 if (best_edge && EDGE_COUNT (best_edge->dest->preds) >= 2
|
|
|
551 && copy_bb_p (best_edge->dest, 0))
|
|
|
552 best_edge = NULL;
|
|
|
553
|
|
|
554 /* Add all non-selected successors to the heaps. */
|
|
|
555 FOR_EACH_EDGE (e, ei, bb->succs)
|
|
|
556 {
|
|
|
557 if (e == best_edge
|
|
|
558 || e->dest == EXIT_BLOCK_PTR
|
|
|
559 || e->dest->il.rtl->visited)
|
|
|
560 continue;
|
|
|
561
|
|
|
562 key = bb_to_key (e->dest);
|
|
|
563
|
|
|
564 if (bbd[e->dest->index].heap)
|
|
|
565 {
|
|
|
566 /* E->DEST is already in some heap. */
|
|
|
567 if (key != bbd[e->dest->index].node->key)
|
|
|
568 {
|
|
|
569 if (dump_file)
|
|
|
570 {
|
|
|
571 fprintf (dump_file,
|
|
|
572 "Changing key for bb %d from %ld to %ld.\n",
|
|
|
573 e->dest->index,
|
|
|
574 (long) bbd[e->dest->index].node->key,
|
|
|
575 key);
|
|
|
576 }
|
|
|
577 fibheap_replace_key (bbd[e->dest->index].heap,
|
|
|
578 bbd[e->dest->index].node, key);
|
|
|
579 }
|
|
|
580 }
|
|
|
581 else
|
|
|
582 {
|
|
|
583 fibheap_t which_heap = *heap;
|
|
|
584
|
|
|
585 prob = e->probability;
|
|
|
586 freq = EDGE_FREQUENCY (e);
|
|
|
587
|
|
|
588 if (!(e->flags & EDGE_CAN_FALLTHRU)
|
|
|
589 || (e->flags & EDGE_COMPLEX)
|
|
|
590 || prob < branch_th || freq < exec_th
|
|
|
591 || e->count < count_th)
|
|
|
592 {
|
|
|
593 /* When partitioning hot/cold basic blocks, make sure
|
|
|
594 the cold blocks (and only the cold blocks) all get
|
|
|
595 pushed to the last round of trace collection. */
|
|
|
596
|
|
|
597 if (push_to_next_round_p (e->dest, round,
|
|
|
598 number_of_rounds,
|
|
|
599 exec_th, count_th))
|
|
|
600 which_heap = new_heap;
|
|
|
601 }
|
|
|
602
|
|
|
603 bbd[e->dest->index].heap = which_heap;
|
|
|
604 bbd[e->dest->index].node = fibheap_insert (which_heap,
|
|
|
605 key, e->dest);
|
|
|
606
|
|
|
607 if (dump_file)
|
|
|
608 {
|
|
|
609 fprintf (dump_file,
|
|
|
610 " Possible start of %s round: %d (key: %ld)\n",
|
|
|
611 (which_heap == new_heap) ? "next" : "this",
|
|
|
612 e->dest->index, (long) key);
|
|
|
613 }
|
|
|
614
|
|
|
615 }
|
|
|
616 }
|
|
|
617
|
|
|
618 if (best_edge) /* Suitable successor was found. */
|
|
|
619 {
|
|
|
620 if (best_edge->dest->il.rtl->visited == *n_traces)
|
|
|
621 {
|
|
|
622 /* We do nothing with one basic block loops. */
|
|
|
623 if (best_edge->dest != bb)
|
|
|
624 {
|
|
|
625 if (EDGE_FREQUENCY (best_edge)
|
|
|
626 > 4 * best_edge->dest->frequency / 5)
|
|
|
627 {
|
|
|
628 /* The loop has at least 4 iterations. If the loop
|
|
|
629 header is not the first block of the function
|
|
|
630 we can rotate the loop. */
|
|
|
631
|
|
|
632 if (best_edge->dest != ENTRY_BLOCK_PTR->next_bb)
|
|
|
633 {
|
|
|
634 if (dump_file)
|
|
|
635 {
|
|
|
636 fprintf (dump_file,
|
|
|
637 "Rotating loop %d - %d\n",
|
|
|
638 best_edge->dest->index, bb->index);
|
|
|
639 }
|
|
|
640 bb->aux = best_edge->dest;
|
|
|
641 bbd[best_edge->dest->index].in_trace =
|
|
|
642 (*n_traces) - 1;
|
|
|
643 bb = rotate_loop (best_edge, trace, *n_traces);
|
|
|
644 }
|
|
|
645 }
|
|
|
646 else
|
|
|
647 {
|
|
|
648 /* The loop has less than 4 iterations. */
|
|
|
649
|
|
|
650 if (single_succ_p (bb)
|
|
|
651 && copy_bb_p (best_edge->dest,
|
|
|
652 optimize_edge_for_speed_p (best_edge)))
|
|
|
653 {
|
|
|
654 bb = copy_bb (best_edge->dest, best_edge, bb,
|
|
|
655 *n_traces);
|
|
|
656 trace->length++;
|
|
|
657 }
|
|
|
658 }
|
|
|
659 }
|
|
|
660
|
|
|
661 /* Terminate the trace. */
|
|
|
662 break;
|
|
|
663 }
|
|
|
664 else
|
|
|
665 {
|
|
|
666 /* Check for a situation
|
|
|
667
|
|
|
668 A
|
|
|
669 /|
|
|
|
670 B |
|
|
|
671 \|
|
|
|
672 C
|
|
|
673
|
|
|
674 where
|
|
|
675 EDGE_FREQUENCY (AB) + EDGE_FREQUENCY (BC)
|
|
|
676 >= EDGE_FREQUENCY (AC).
|
|
|
677 (i.e. 2 * B->frequency >= EDGE_FREQUENCY (AC) )
|
|
|
678 Best ordering is then A B C.
|
|
|
679
|
|
|
680 This situation is created for example by:
|
|
|
681
|
|
|
682 if (A) B;
|
|
|
683 C;
|
|
|
684
|
|
|
685 */
|
|
|
686
|
|
|
687 FOR_EACH_EDGE (e, ei, bb->succs)
|
|
|
688 if (e != best_edge
|
|
|
689 && (e->flags & EDGE_CAN_FALLTHRU)
|
|
|
690 && !(e->flags & EDGE_COMPLEX)
|
|
|
691 && !e->dest->il.rtl->visited
|
|
|
692 && single_pred_p (e->dest)
|
|
|
693 && !(e->flags & EDGE_CROSSING)
|
|
|
694 && single_succ_p (e->dest)
|
|
|
695 && (single_succ_edge (e->dest)->flags
|
|
|
696 & EDGE_CAN_FALLTHRU)
|
|
|
697 && !(single_succ_edge (e->dest)->flags & EDGE_COMPLEX)
|
|
|
698 && single_succ (e->dest) == best_edge->dest
|
|
|
699 && 2 * e->dest->frequency >= EDGE_FREQUENCY (best_edge))
|
|
|
700 {
|
|
|
701 best_edge = e;
|
|
|
702 if (dump_file)
|
|
|
703 fprintf (dump_file, "Selecting BB %d\n",
|
|
|
704 best_edge->dest->index);
|
|
|
705 break;
|
|
|
706 }
|
|
|
707
|
|
|
708 bb->aux = best_edge->dest;
|
|
|
709 bbd[best_edge->dest->index].in_trace = (*n_traces) - 1;
|
|
|
710 bb = best_edge->dest;
|
|
|
711 }
|
|
|
712 }
|
|
|
713 }
|
|
|
714 while (best_edge);
|
|
|
715 trace->last = bb;
|
|
|
716 bbd[trace->first->index].start_of_trace = *n_traces - 1;
|
|
|
717 bbd[trace->last->index].end_of_trace = *n_traces - 1;
|
|
|
718
|
|
|
719 /* The trace is terminated so we have to recount the keys in heap
|
|
|
720 (some block can have a lower key because now one of its predecessors
|
|
|
721 is an end of the trace). */
|
|
|
722 FOR_EACH_EDGE (e, ei, bb->succs)
|
|
|
723 {
|
|
|
724 if (e->dest == EXIT_BLOCK_PTR
|
|
|
725 || e->dest->il.rtl->visited)
|
|
|
726 continue;
|
|
|
727
|
|
|
728 if (bbd[e->dest->index].heap)
|
|
|
729 {
|
|
|
730 key = bb_to_key (e->dest);
|
|
|
731 if (key != bbd[e->dest->index].node->key)
|
|
|
732 {
|
|
|
733 if (dump_file)
|
|
|
734 {
|
|
|
735 fprintf (dump_file,
|
|
|
736 "Changing key for bb %d from %ld to %ld.\n",
|
|
|
737 e->dest->index,
|
|
|
738 (long) bbd[e->dest->index].node->key, key);
|
|
|
739 }
|
|
|
740 fibheap_replace_key (bbd[e->dest->index].heap,
|
|
|
741 bbd[e->dest->index].node,
|
|
|
742 key);
|
|
|
743 }
|
|
|
744 }
|
|
|
745 }
|
|
|
746 }
|
|
|
747
|
|
|
748 fibheap_delete (*heap);
|
|
|
749
|
|
|
750 /* "Return" the new heap. */
|
|
|
751 *heap = new_heap;
|
|
|
752 }
|
|
|
753
|
|
|
754 /* Create a duplicate of the basic block OLD_BB and redirect edge E to it, add
|
|
|
755 it to trace after BB, mark OLD_BB visited and update pass' data structures
|
|
|
756 (TRACE is a number of trace which OLD_BB is duplicated to). */
|
|
|
757
|
|
|
758 static basic_block
|
|
|
759 copy_bb (basic_block old_bb, edge e, basic_block bb, int trace)
|
|
|
760 {
|
|
|
761 basic_block new_bb;
|
|
|
762
|
|
|
763 new_bb = duplicate_block (old_bb, e, bb);
|
|
|
764 BB_COPY_PARTITION (new_bb, old_bb);
|
|
|
765
|
|
|
766 gcc_assert (e->dest == new_bb);
|
|
|
767 gcc_assert (!e->dest->il.rtl->visited);
|
|
|
768
|
|
|
769 if (dump_file)
|
|
|
770 fprintf (dump_file,
|
|
|
771 "Duplicated bb %d (created bb %d)\n",
|
|
|
772 old_bb->index, new_bb->index);
|
|
|
773 new_bb->il.rtl->visited = trace;
|
|
|
774 new_bb->aux = bb->aux;
|
|
|
775 bb->aux = new_bb;
|
|
|
776
|
|
|
777 if (new_bb->index >= array_size || last_basic_block > array_size)
|
|
|
778 {
|
|
|
779 int i;
|
|
|
780 int new_size;
|
|
|
781
|
|
|
782 new_size = MAX (last_basic_block, new_bb->index + 1);
|
|
|
783 new_size = GET_ARRAY_SIZE (new_size);
|
|
|
784 bbd = XRESIZEVEC (bbro_basic_block_data, bbd, new_size);
|
|
|
785 for (i = array_size; i < new_size; i++)
|
|
|
786 {
|
|
|
787 bbd[i].start_of_trace = -1;
|
|
|
788 bbd[i].in_trace = -1;
|
|
|
789 bbd[i].end_of_trace = -1;
|
|
|
790 bbd[i].heap = NULL;
|
|
|
791 bbd[i].node = NULL;
|
|
|
792 }
|
|
|
793 array_size = new_size;
|
|
|
794
|
|
|
795 if (dump_file)
|
|
|
796 {
|
|
|
797 fprintf (dump_file,
|
|
|
798 "Growing the dynamic array to %d elements.\n",
|
|
|
799 array_size);
|
|
|
800 }
|
|
|
801 }
|
|
|
802
|
|
|
803 bbd[new_bb->index].in_trace = trace;
|
|
|
804
|
|
|
805 return new_bb;
|
|
|
806 }
|
|
|
807
|
|
|
808 /* Compute and return the key (for the heap) of the basic block BB. */
|
|
|
809
|
|
|
810 static fibheapkey_t
|
|
|
811 bb_to_key (basic_block bb)
|
|
|
812 {
|
|
|
813 edge e;
|
|
|
814 edge_iterator ei;
|
|
|
815 int priority = 0;
|
|
|
816
|
|
|
817 /* Do not start in probably never executed blocks. */
|
|
|
818
|
|
|
819 if (BB_PARTITION (bb) == BB_COLD_PARTITION
|
|
|
820 || probably_never_executed_bb_p (bb))
|
|
|
821 return BB_FREQ_MAX;
|
|
|
822
|
|
|
823 /* Prefer blocks whose predecessor is an end of some trace
|
|
|
824 or whose predecessor edge is EDGE_DFS_BACK. */
|
|
|
825 FOR_EACH_EDGE (e, ei, bb->preds)
|
|
|
826 {
|
|
|
827 if ((e->src != ENTRY_BLOCK_PTR && bbd[e->src->index].end_of_trace >= 0)
|
|
|
828 || (e->flags & EDGE_DFS_BACK))
|
|
|
829 {
|
|
|
830 int edge_freq = EDGE_FREQUENCY (e);
|
|
|
831
|
|
|
832 if (edge_freq > priority)
|
|
|
833 priority = edge_freq;
|
|
|
834 }
|
|
|
835 }
|
|
|
836
|
|
|
837 if (priority)
|
|
|
838 /* The block with priority should have significantly lower key. */
|
|
|
839 return -(100 * BB_FREQ_MAX + 100 * priority + bb->frequency);
|
|
|
840 return -bb->frequency;
|
|
|
841 }
|
|
|
842
|
|
|
843 /* Return true when the edge E from basic block BB is better than the temporary
|
|
|
844 best edge (details are in function). The probability of edge E is PROB. The
|
|
|
845 frequency of the successor is FREQ. The current best probability is
|
|
|
846 BEST_PROB, the best frequency is BEST_FREQ.
|
|
|
847 The edge is considered to be equivalent when PROB does not differ much from
|
|
|
848 BEST_PROB; similarly for frequency. */
|
|
|
849
|
|
|
850 static bool
|
|
|
851 better_edge_p (const_basic_block bb, const_edge e, int prob, int freq, int best_prob,
|
|
|
852 int best_freq, const_edge cur_best_edge)
|
|
|
853 {
|
|
|
854 bool is_better_edge;
|
|
|
855
|
|
|
856 /* The BEST_* values do not have to be best, but can be a bit smaller than
|
|
|
857 maximum values. */
|
|
|
858 int diff_prob = best_prob / 10;
|
|
|
859 int diff_freq = best_freq / 10;
|
|
|
860
|
|
|
861 if (prob > best_prob + diff_prob)
|
|
|
862 /* The edge has higher probability than the temporary best edge. */
|
|
|
863 is_better_edge = true;
|
|
|
864 else if (prob < best_prob - diff_prob)
|
|
|
865 /* The edge has lower probability than the temporary best edge. */
|
|
|
866 is_better_edge = false;
|
|
|
867 else if (freq < best_freq - diff_freq)
|
|
|
868 /* The edge and the temporary best edge have almost equivalent
|
|
|
869 probabilities. The higher frequency of a successor now means
|
|
|
870 that there is another edge going into that successor.
|
|
|
871 This successor has lower frequency so it is better. */
|
|
|
872 is_better_edge = true;
|
|
|
873 else if (freq > best_freq + diff_freq)
|
|
|
874 /* This successor has higher frequency so it is worse. */
|
|
|
875 is_better_edge = false;
|
|
|
876 else if (e->dest->prev_bb == bb)
|
|
|
877 /* The edges have equivalent probabilities and the successors
|
|
|
878 have equivalent frequencies. Select the previous successor. */
|
|
|
879 is_better_edge = true;
|
|
|
880 else
|
|
|
881 is_better_edge = false;
|
|
|
882
|
|
|
883 /* If we are doing hot/cold partitioning, make sure that we always favor
|
|
|
884 non-crossing edges over crossing edges. */
|
|
|
885
|
|
|
886 if (!is_better_edge
|
|
|
887 && flag_reorder_blocks_and_partition
|
|
|
888 && cur_best_edge
|
|
|
889 && (cur_best_edge->flags & EDGE_CROSSING)
|
|
|
890 && !(e->flags & EDGE_CROSSING))
|
|
|
891 is_better_edge = true;
|
|
|
892
|
|
|
893 return is_better_edge;
|
|
|
894 }
|
|
|
895
|
|
|
896 /* Connect traces in array TRACES, N_TRACES is the count of traces. */
|
|
|
897
|
|
|
898 static void
|
|
|
899 connect_traces (int n_traces, struct trace *traces)
|
|
|
900 {
|
|
|
901 int i;
|
|
|
902 bool *connected;
|
|
|
903 bool two_passes;
|
|
|
904 int last_trace;
|
|
|
905 int current_pass;
|
|
|
906 int current_partition;
|
|
|
907 int freq_threshold;
|
|
|
908 gcov_type count_threshold;
|
|
|
909
|
|
|
910 freq_threshold = max_entry_frequency * DUPLICATION_THRESHOLD / 1000;
|
|
|
911 if (max_entry_count < INT_MAX / 1000)
|
|
|
912 count_threshold = max_entry_count * DUPLICATION_THRESHOLD / 1000;
|
|
|
913 else
|
|
|
914 count_threshold = max_entry_count / 1000 * DUPLICATION_THRESHOLD;
|
|
|
915
|
|
|
916 connected = XCNEWVEC (bool, n_traces);
|
|
|
917 last_trace = -1;
|
|
|
918 current_pass = 1;
|
|
|
919 current_partition = BB_PARTITION (traces[0].first);
|
|
|
920 two_passes = false;
|
|
|
921
|
|
|
922 if (flag_reorder_blocks_and_partition)
|
|
|
923 for (i = 0; i < n_traces && !two_passes; i++)
|
|
|
924 if (BB_PARTITION (traces[0].first)
|
|
|
925 != BB_PARTITION (traces[i].first))
|
|
|
926 two_passes = true;
|
|
|
927
|
|
|
928 for (i = 0; i < n_traces || (two_passes && current_pass == 1) ; i++)
|
|
|
929 {
|
|
|
930 int t = i;
|
|
|
931 int t2;
|
|
|
932 edge e, best;
|
|
|
933 int best_len;
|
|
|
934
|
|
|
935 if (i >= n_traces)
|
|
|
936 {
|
|
|
937 gcc_assert (two_passes && current_pass == 1);
|
|
|
938 i = 0;
|
|
|
939 t = i;
|
|
|
940 current_pass = 2;
|
|
|
941 if (current_partition == BB_HOT_PARTITION)
|
|
|
942 current_partition = BB_COLD_PARTITION;
|
|
|
943 else
|
|
|
944 current_partition = BB_HOT_PARTITION;
|
|
|
945 }
|
|
|
946
|
|
|
947 if (connected[t])
|
|
|
948 continue;
|
|
|
949
|
|
|
950 if (two_passes
|
|
|
951 && BB_PARTITION (traces[t].first) != current_partition)
|
|
|
952 continue;
|
|
|
953
|
|
|
954 connected[t] = true;
|
|
|
955
|
|
|
956 /* Find the predecessor traces. */
|
|
|
957 for (t2 = t; t2 > 0;)
|
|
|
958 {
|
|
|
959 edge_iterator ei;
|
|
|
960 best = NULL;
|
|
|
961 best_len = 0;
|
|
|
962 FOR_EACH_EDGE (e, ei, traces[t2].first->preds)
|
|
|
963 {
|
|
|
964 int si = e->src->index;
|
|
|
965
|
|
|
966 if (e->src != ENTRY_BLOCK_PTR
|
|
|
967 && (e->flags & EDGE_CAN_FALLTHRU)
|
|
|
968 && !(e->flags & EDGE_COMPLEX)
|
|
|
969 && bbd[si].end_of_trace >= 0
|
|
|
970 && !connected[bbd[si].end_of_trace]
|
|
|
971 && (BB_PARTITION (e->src) == current_partition)
|
|
|
972 && (!best
|
|
|
973 || e->probability > best->probability
|
|
|
974 || (e->probability == best->probability
|
|
|
975 && traces[bbd[si].end_of_trace].length > best_len)))
|
|
|
976 {
|
|
|
977 best = e;
|
|
|
978 best_len = traces[bbd[si].end_of_trace].length;
|
|
|
979 }
|
|
|
980 }
|
|
|
981 if (best)
|
|
|
982 {
|
|
|
983 best->src->aux = best->dest;
|
|
|
984 t2 = bbd[best->src->index].end_of_trace;
|
|
|
985 connected[t2] = true;
|
|
|
986
|
|
|
987 if (dump_file)
|
|
|
988 {
|
|
|
989 fprintf (dump_file, "Connection: %d %d\n",
|
|
|
990 best->src->index, best->dest->index);
|
|
|
991 }
|
|
|
992 }
|
|
|
993 else
|
|
|
994 break;
|
|
|
995 }
|
|
|
996
|
|
|
997 if (last_trace >= 0)
|
|
|
998 traces[last_trace].last->aux = traces[t2].first;
|
|
|
999 last_trace = t;
|
|
|
1000
|
|
|
1001 /* Find the successor traces. */
|
|
|
1002 while (1)
|
|
|
1003 {
|
|
|
1004 /* Find the continuation of the chain. */
|
|
|
1005 edge_iterator ei;
|
|
|
1006 best = NULL;
|
|
|
1007 best_len = 0;
|
|
|
1008 FOR_EACH_EDGE (e, ei, traces[t].last->succs)
|
|
|
1009 {
|
|
|
1010 int di = e->dest->index;
|
|
|
1011
|
|
|
1012 if (e->dest != EXIT_BLOCK_PTR
|
|
|
1013 && (e->flags & EDGE_CAN_FALLTHRU)
|
|
|
1014 && !(e->flags & EDGE_COMPLEX)
|
|
|
1015 && bbd[di].start_of_trace >= 0
|
|
|
1016 && !connected[bbd[di].start_of_trace]
|
|
|
1017 && (BB_PARTITION (e->dest) == current_partition)
|
|
|
1018 && (!best
|
|
|
1019 || e->probability > best->probability
|
|
|
1020 || (e->probability == best->probability
|
|
|
1021 && traces[bbd[di].start_of_trace].length > best_len)))
|
|
|
1022 {
|
|
|
1023 best = e;
|
|
|
1024 best_len = traces[bbd[di].start_of_trace].length;
|
|
|
1025 }
|
|
|
1026 }
|
|
|
1027
|
|
|
1028 if (best)
|
|
|
1029 {
|
|
|
1030 if (dump_file)
|
|
|
1031 {
|
|
|
1032 fprintf (dump_file, "Connection: %d %d\n",
|
|
|
1033 best->src->index, best->dest->index);
|
|
|
1034 }
|
|
|
1035 t = bbd[best->dest->index].start_of_trace;
|
|
|
1036 traces[last_trace].last->aux = traces[t].first;
|
|
|
1037 connected[t] = true;
|
|
|
1038 last_trace = t;
|
|
|
1039 }
|
|
|
1040 else
|
|
|
1041 {
|
|
|
1042 /* Try to connect the traces by duplication of 1 block. */
|
|
|
1043 edge e2;
|
|
|
1044 basic_block next_bb = NULL;
|
|
|
1045 bool try_copy = false;
|
|
|
1046
|
|
|
1047 FOR_EACH_EDGE (e, ei, traces[t].last->succs)
|
|
|
1048 if (e->dest != EXIT_BLOCK_PTR
|
|
|
1049 && (e->flags & EDGE_CAN_FALLTHRU)
|
|
|
1050 && !(e->flags & EDGE_COMPLEX)
|
|
|
1051 && (!best || e->probability > best->probability))
|
|
|
1052 {
|
|
|
1053 edge_iterator ei;
|
|
|
1054 edge best2 = NULL;
|
|
|
1055 int best2_len = 0;
|
|
|
1056
|
|
|
1057 /* If the destination is a start of a trace which is only
|
|
|
1058 one block long, then no need to search the successor
|
|
|
1059 blocks of the trace. Accept it. */
|
|
|
1060 if (bbd[e->dest->index].start_of_trace >= 0
|
|
|
1061 && traces[bbd[e->dest->index].start_of_trace].length
|
|
|
1062 == 1)
|
|
|
1063 {
|
|
|
1064 best = e;
|
|
|
1065 try_copy = true;
|
|
|
1066 continue;
|
|
|
1067 }
|
|
|
1068
|
|
|
1069 FOR_EACH_EDGE (e2, ei, e->dest->succs)
|
|
|
1070 {
|
|
|
1071 int di = e2->dest->index;
|
|
|
1072
|
|
|
1073 if (e2->dest == EXIT_BLOCK_PTR
|
|
|
1074 || ((e2->flags & EDGE_CAN_FALLTHRU)
|
|
|
1075 && !(e2->flags & EDGE_COMPLEX)
|
|
|
1076 && bbd[di].start_of_trace >= 0
|
|
|
1077 && !connected[bbd[di].start_of_trace]
|
|
|
1078 && (BB_PARTITION (e2->dest) == current_partition)
|
|
|
1079 && (EDGE_FREQUENCY (e2) >= freq_threshold)
|
|
|
1080 && (e2->count >= count_threshold)
|
|
|
1081 && (!best2
|
|
|
1082 || e2->probability > best2->probability
|
|
|
1083 || (e2->probability == best2->probability
|
|
|
1084 && traces[bbd[di].start_of_trace].length
|
|
|
1085 > best2_len))))
|
|
|
1086 {
|
|
|
1087 best = e;
|
|
|
1088 best2 = e2;
|
|
|
1089 if (e2->dest != EXIT_BLOCK_PTR)
|
|
|
1090 best2_len = traces[bbd[di].start_of_trace].length;
|
|
|
1091 else
|
|
|
1092 best2_len = INT_MAX;
|
|
|
1093 next_bb = e2->dest;
|
|
|
1094 try_copy = true;
|
|
|
1095 }
|
|
|
1096 }
|
|
|
1097 }
|
|
|
1098
|
|
|
1099 if (flag_reorder_blocks_and_partition)
|
|
|
1100 try_copy = false;
|
|
|
1101
|
|
|
1102 /* Copy tiny blocks always; copy larger blocks only when the
|
|
|
1103 edge is traversed frequently enough. */
|
|
|
1104 if (try_copy
|
|
|
1105 && copy_bb_p (best->dest,
|
|
|
1106 optimize_edge_for_speed_p (best)
|
|
|
1107 && EDGE_FREQUENCY (best) >= freq_threshold
|
|
|
1108 && best->count >= count_threshold))
|
|
|
1109 {
|
|
|
1110 basic_block new_bb;
|
|
|
1111
|
|
|
1112 if (dump_file)
|
|
|
1113 {
|
|
|
1114 fprintf (dump_file, "Connection: %d %d ",
|
|
|
1115 traces[t].last->index, best->dest->index);
|
|
|
1116 if (!next_bb)
|
|
|
1117 fputc ('\n', dump_file);
|
|
|
1118 else if (next_bb == EXIT_BLOCK_PTR)
|
|
|
1119 fprintf (dump_file, "exit\n");
|
|
|
1120 else
|
|
|
1121 fprintf (dump_file, "%d\n", next_bb->index);
|
|
|
1122 }
|
|
|
1123
|
|
|
1124 new_bb = copy_bb (best->dest, best, traces[t].last, t);
|
|
|
1125 traces[t].last = new_bb;
|
|
|
1126 if (next_bb && next_bb != EXIT_BLOCK_PTR)
|
|
|
1127 {
|
|
|
1128 t = bbd[next_bb->index].start_of_trace;
|
|
|
1129 traces[last_trace].last->aux = traces[t].first;
|
|
|
1130 connected[t] = true;
|
|
|
1131 last_trace = t;
|
|
|
1132 }
|
|
|
1133 else
|
|
|
1134 break; /* Stop finding the successor traces. */
|
|
|
1135 }
|
|
|
1136 else
|
|
|
1137 break; /* Stop finding the successor traces. */
|
|
|
1138 }
|
|
|
1139 }
|
|
|
1140 }
|
|
|
1141
|
|
|
1142 if (dump_file)
|
|
|
1143 {
|
|
|
1144 basic_block bb;
|
|
|
1145
|
|
|
1146 fprintf (dump_file, "Final order:\n");
|
|
|
1147 for (bb = traces[0].first; bb; bb = (basic_block) bb->aux)
|
|
|
1148 fprintf (dump_file, "%d ", bb->index);
|
|
|
1149 fprintf (dump_file, "\n");
|
|
|
1150 fflush (dump_file);
|
|
|
1151 }
|
|
|
1152
|
|
|
1153 FREE (connected);
|
|
|
1154 }
|
|
|
1155
|
|
|
1156 /* Return true when BB can and should be copied. CODE_MAY_GROW is true
|
|
|
1157 when code size is allowed to grow by duplication. */
|
|
|
1158
|
|
|
1159 static bool
|
|
|
1160 copy_bb_p (const_basic_block bb, int code_may_grow)
|
|
|
1161 {
|
|
|
1162 int size = 0;
|
|
|
1163 int max_size = uncond_jump_length;
|
|
|
1164 rtx insn;
|
|
|
1165
|
|
|
1166 if (!bb->frequency)
|
|
|
1167 return false;
|
|
|
1168 if (EDGE_COUNT (bb->preds) < 2)
|
|
|
1169 return false;
|
|
|
1170 if (!can_duplicate_block_p (bb))
|
|
|
1171 return false;
|
|
|
1172
|
|
|
1173 /* Avoid duplicating blocks which have many successors (PR/13430). */
|
|
|
1174 if (EDGE_COUNT (bb->succs) > 8)
|
|
|
1175 return false;
|
|
|
1176
|
|
|
1177 if (code_may_grow && optimize_bb_for_speed_p (bb))
|
|
|
1178 max_size *= PARAM_VALUE (PARAM_MAX_GROW_COPY_BB_INSNS);
|
|
|
1179
|
|
|
1180 FOR_BB_INSNS (bb, insn)
|
|
|
1181 {
|
|
|
1182 if (INSN_P (insn))
|
|
|
1183 size += get_attr_min_length (insn);
|
|
|
1184 }
|
|
|
1185
|
|
|
1186 if (size <= max_size)
|
|
|
1187 return true;
|
|
|
1188
|
|
|
1189 if (dump_file)
|
|
|
1190 {
|
|
|
1191 fprintf (dump_file,
|
|
|
1192 "Block %d can't be copied because its size = %d.\n",
|
|
|
1193 bb->index, size);
|
|
|
1194 }
|
|
|
1195
|
|
|
1196 return false;
|
|
|
1197 }
|
|
|
1198
|
|
|
1199 /* Return the length of unconditional jump instruction. */
|
|
|
1200
|
|
|
1201 static int
|
|
|
1202 get_uncond_jump_length (void)
|
|
|
1203 {
|
|
|
1204 rtx label, jump;
|
|
|
1205 int length;
|
|
|
1206
|
|
|
1207 label = emit_label_before (gen_label_rtx (), get_insns ());
|
|
|
1208 jump = emit_jump_insn (gen_jump (label));
|
|
|
1209
|
|
|
1210 length = get_attr_min_length (jump);
|
|
|
1211
|
|
|
1212 delete_insn (jump);
|
|
|
1213 delete_insn (label);
|
|
|
1214 return length;
|
|
|
1215 }
|
|
|
1216
|
|
|
1217 /* Find the basic blocks that are rarely executed and need to be moved to
|
|
|
1218 a separate section of the .o file (to cut down on paging and improve
|
|
|
1219 cache locality). */
|
|
|
1220
|
|
|
1221 static void
|
|
|
1222 find_rarely_executed_basic_blocks_and_crossing_edges (edge **crossing_edges,
|
|
|
1223 int *n_crossing_edges,
|
|
|
1224 int *max_idx)
|
|
|
1225 {
|
|
|
1226 basic_block bb;
|
|
|
1227 edge e;
|
|
|
1228 int i;
|
|
|
1229 edge_iterator ei;
|
|
|
1230
|
|
|
1231 /* Mark which partition (hot/cold) each basic block belongs in. */
|
|
|
1232
|
|
|
1233 FOR_EACH_BB (bb)
|
|
|
1234 {
|
|
|
1235 if (probably_never_executed_bb_p (bb))
|
|
|
1236 BB_SET_PARTITION (bb, BB_COLD_PARTITION);
|
|
|
1237 else
|
|
|
1238 BB_SET_PARTITION (bb, BB_HOT_PARTITION);
|
|
|
1239 }
|
|
|
1240
|
|
|
1241 /* Mark every edge that crosses between sections. */
|
|
|
1242
|
|
|
1243 i = 0;
|
|
|
1244 FOR_EACH_BB (bb)
|
|
|
1245 FOR_EACH_EDGE (e, ei, bb->succs)
|
|
|
1246 {
|
|
|
1247 if (e->src != ENTRY_BLOCK_PTR
|
|
|
1248 && e->dest != EXIT_BLOCK_PTR
|
|
|
1249 && BB_PARTITION (e->src) != BB_PARTITION (e->dest))
|
|
|
1250 {
|
|
|
1251 e->flags |= EDGE_CROSSING;
|
|
|
1252 if (i == *max_idx)
|
|
|
1253 {
|
|
|
1254 *max_idx *= 2;
|
|
|
1255 *crossing_edges = XRESIZEVEC (edge, *crossing_edges, *max_idx);
|
|
|
1256 }
|
|
|
1257 (*crossing_edges)[i++] = e;
|
|
|
1258 }
|
|
|
1259 else
|
|
|
1260 e->flags &= ~EDGE_CROSSING;
|
|
|
1261 }
|
|
|
1262 *n_crossing_edges = i;
|
|
|
1263 }
|
|
|
1264
|
|
|
1265 /* If any destination of a crossing edge does not have a label, add label;
|
|
|
1266 Convert any fall-through crossing edges (for blocks that do not contain
|
|
|
1267 a jump) to unconditional jumps. */
|
|
|
1268
|
|
|
1269 static void
|
|
|
1270 add_labels_and_missing_jumps (edge *crossing_edges, int n_crossing_edges)
|
|
|
1271 {
|
|
|
1272 int i;
|
|
|
1273 basic_block src;
|
|
|
1274 basic_block dest;
|
|
|
1275 rtx label;
|
|
|
1276 rtx barrier;
|
|
|
1277 rtx new_jump;
|
|
|
1278
|
|
|
1279 for (i=0; i < n_crossing_edges; i++)
|
|
|
1280 {
|
|
|
1281 if (crossing_edges[i])
|
|
|
1282 {
|
|
|
1283 src = crossing_edges[i]->src;
|
|
|
1284 dest = crossing_edges[i]->dest;
|
|
|
1285
|
|
|
1286 /* Make sure dest has a label. */
|
|
|
1287
|
|
|
1288 if (dest && (dest != EXIT_BLOCK_PTR))
|
|
|
1289 {
|
|
|
1290 label = block_label (dest);
|
|
|
1291
|
|
|
1292 /* Make sure source block ends with a jump. If the
|
|
|
1293 source block does not end with a jump it might end
|
|
|
1294 with a call_insn; this case will be handled in
|
|
|
1295 fix_up_fall_thru_edges function. */
|
|
|
1296
|
|
|
1297 if (src && (src != ENTRY_BLOCK_PTR))
|
|
|
1298 {
|
|
|
1299 if (!JUMP_P (BB_END (src)) && !block_ends_with_call_p (src))
|
|
|
1300 /* bb just falls through. */
|
|
|
1301 {
|
|
|
1302 /* make sure there's only one successor */
|
|
|
1303 gcc_assert (single_succ_p (src));
|
|
|
1304
|
|
|
1305 /* Find label in dest block. */
|
|
|
1306 label = block_label (dest);
|
|
|
1307
|
|
|
1308 new_jump = emit_jump_insn_after (gen_jump (label),
|
|
|
1309 BB_END (src));
|
|
|
1310 barrier = emit_barrier_after (new_jump);
|
|
|
1311 JUMP_LABEL (new_jump) = label;
|
|
|
1312 LABEL_NUSES (label) += 1;
|
|
|
1313 src->il.rtl->footer = unlink_insn_chain (barrier, barrier);
|
|
|
1314 /* Mark edge as non-fallthru. */
|
|
|
1315 crossing_edges[i]->flags &= ~EDGE_FALLTHRU;
|
|
|
1316 } /* end: 'if (GET_CODE ... ' */
|
|
|
1317 } /* end: 'if (src && src->index...' */
|
|
|
1318 } /* end: 'if (dest && dest->index...' */
|
|
|
1319 } /* end: 'if (crossing_edges[i]...' */
|
|
|
1320 } /* end for loop */
|
|
|
1321 }
|
|
|
1322
|
|
|
1323 /* Find any bb's where the fall-through edge is a crossing edge (note that
|
|
|
1324 these bb's must also contain a conditional jump or end with a call
|
|
|
1325 instruction; we've already dealt with fall-through edges for blocks
|
|
|
1326 that didn't have a conditional jump or didn't end with call instruction
|
|
|
1327 in the call to add_labels_and_missing_jumps). Convert the fall-through
|
|
|
1328 edge to non-crossing edge by inserting a new bb to fall-through into.
|
|
|
1329 The new bb will contain an unconditional jump (crossing edge) to the
|
|
|
1330 original fall through destination. */
|
|
|
1331
|
|
|
1332 static void
|
|
|
1333 fix_up_fall_thru_edges (void)
|
|
|
1334 {
|
|
|
1335 basic_block cur_bb;
|
|
|
1336 basic_block new_bb;
|
|
|
1337 edge succ1;
|
|
|
1338 edge succ2;
|
|
|
1339 edge fall_thru;
|
|
|
1340 edge cond_jump = NULL;
|
|
|
1341 edge e;
|
|
|
1342 bool cond_jump_crosses;
|
|
|
1343 int invert_worked;
|
|
|
1344 rtx old_jump;
|
|
|
1345 rtx fall_thru_label;
|
|
|
1346 rtx barrier;
|
|
|
1347
|
|
|
1348 FOR_EACH_BB (cur_bb)
|
|
|
1349 {
|
|
|
1350 fall_thru = NULL;
|
|
|
1351 if (EDGE_COUNT (cur_bb->succs) > 0)
|
|
|
1352 succ1 = EDGE_SUCC (cur_bb, 0);
|
|
|
1353 else
|
|
|
1354 succ1 = NULL;
|
|
|
1355
|
|
|
1356 if (EDGE_COUNT (cur_bb->succs) > 1)
|
|
|
1357 succ2 = EDGE_SUCC (cur_bb, 1);
|
|
|
1358 else
|
|
|
1359 succ2 = NULL;
|
|
|
1360
|
|
|
1361 /* Find the fall-through edge. */
|
|
|
1362
|
|
|
1363 if (succ1
|
|
|
1364 && (succ1->flags & EDGE_FALLTHRU))
|
|
|
1365 {
|
|
|
1366 fall_thru = succ1;
|
|
|
1367 cond_jump = succ2;
|
|
|
1368 }
|
|
|
1369 else if (succ2
|
|
|
1370 && (succ2->flags & EDGE_FALLTHRU))
|
|
|
1371 {
|
|
|
1372 fall_thru = succ2;
|
|
|
1373 cond_jump = succ1;
|
|
|
1374 }
|
|
|
1375 else if (!fall_thru && succ1 && block_ends_with_call_p (cur_bb))
|
|
|
1376 {
|
|
|
1377 edge e;
|
|
|
1378 edge_iterator ei;
|
|
|
1379
|
|
|
1380 /* Find EDGE_CAN_FALLTHRU edge. */
|
|
|
1381 FOR_EACH_EDGE (e, ei, cur_bb->succs)
|
|
|
1382 if (e->flags & EDGE_CAN_FALLTHRU)
|
|
|
1383 {
|
|
|
1384 fall_thru = e;
|
|
|
1385 break;
|
|
|
1386 }
|
|
|
1387 }
|
|
|
1388
|
|
|
1389 if (fall_thru && (fall_thru->dest != EXIT_BLOCK_PTR))
|
|
|
1390 {
|
|
|
1391 /* Check to see if the fall-thru edge is a crossing edge. */
|
|
|
1392
|
|
|
1393 if (fall_thru->flags & EDGE_CROSSING)
|
|
|
1394 {
|
|
|
1395 /* The fall_thru edge crosses; now check the cond jump edge, if
|
|
|
1396 it exists. */
|
|
|
1397
|
|
|
1398 cond_jump_crosses = true;
|
|
|
1399 invert_worked = 0;
|
|
|
1400 old_jump = BB_END (cur_bb);
|
|
|
1401
|
|
|
1402 /* Find the jump instruction, if there is one. */
|
|
|
1403
|
|
|
1404 if (cond_jump)
|
|
|
1405 {
|
|
|
1406 if (!(cond_jump->flags & EDGE_CROSSING))
|
|
|
1407 cond_jump_crosses = false;
|
|
|
1408
|
|
|
1409 /* We know the fall-thru edge crosses; if the cond
|
|
|
1410 jump edge does NOT cross, and its destination is the
|
|
|
1411 next block in the bb order, invert the jump
|
|
|
1412 (i.e. fix it so the fall thru does not cross and
|
|
|
1413 the cond jump does). */
|
|
|
1414
|
|
|
1415 if (!cond_jump_crosses
|
|
|
1416 && cur_bb->aux == cond_jump->dest)
|
|
|
1417 {
|
|
|
1418 /* Find label in fall_thru block. We've already added
|
|
|
1419 any missing labels, so there must be one. */
|
|
|
1420
|
|
|
1421 fall_thru_label = block_label (fall_thru->dest);
|
|
|
1422
|
|
|
1423 if (old_jump && fall_thru_label)
|
|
|
1424 invert_worked = invert_jump (old_jump,
|
|
|
1425 fall_thru_label,0);
|
|
|
1426 if (invert_worked)
|
|
|
1427 {
|
|
|
1428 fall_thru->flags &= ~EDGE_FALLTHRU;
|
|
|
1429 cond_jump->flags |= EDGE_FALLTHRU;
|
|
|
1430 update_br_prob_note (cur_bb);
|
|
|
1431 e = fall_thru;
|
|
|
1432 fall_thru = cond_jump;
|
|
|
1433 cond_jump = e;
|
|
|
1434 cond_jump->flags |= EDGE_CROSSING;
|
|
|
1435 fall_thru->flags &= ~EDGE_CROSSING;
|
|
|
1436 }
|
|
|
1437 }
|
|
|
1438 }
|
|
|
1439
|
|
|
1440 if (cond_jump_crosses || !invert_worked)
|
|
|
1441 {
|
|
|
1442 /* This is the case where both edges out of the basic
|
|
|
1443 block are crossing edges. Here we will fix up the
|
|
|
1444 fall through edge. The jump edge will be taken care
|
|
|
1445 of later. The EDGE_CROSSING flag of fall_thru edge
|
|
|
1446 is unset before the call to force_nonfallthru
|
|
|
1447 function because if a new basic-block is created
|
|
|
1448 this edge remains in the current section boundary
|
|
|
1449 while the edge between new_bb and the fall_thru->dest
|
|
|
1450 becomes EDGE_CROSSING. */
|
|
|
1451
|
|
|
1452 fall_thru->flags &= ~EDGE_CROSSING;
|
|
|
1453 new_bb = force_nonfallthru (fall_thru);
|
|
|
1454
|
|
|
1455 if (new_bb)
|
|
|
1456 {
|
|
|
1457 new_bb->aux = cur_bb->aux;
|
|
|
1458 cur_bb->aux = new_bb;
|
|
|
1459
|
|
|
1460 /* Make sure new fall-through bb is in same
|
|
|
1461 partition as bb it's falling through from. */
|
|
|
1462
|
|
|
1463 BB_COPY_PARTITION (new_bb, cur_bb);
|
|
|
1464 single_succ_edge (new_bb)->flags |= EDGE_CROSSING;
|
|
|
1465 }
|
|
|
1466 else
|
|
|
1467 {
|
|
|
1468 /* If a new basic-block was not created; restore
|
|
|
1469 the EDGE_CROSSING flag. */
|
|
|
1470 fall_thru->flags |= EDGE_CROSSING;
|
|
|
1471 }
|
|
|
1472
|
|
|
1473 /* Add barrier after new jump */
|
|
|
1474
|
|
|
1475 if (new_bb)
|
|
|
1476 {
|
|
|
1477 barrier = emit_barrier_after (BB_END (new_bb));
|
|
|
1478 new_bb->il.rtl->footer = unlink_insn_chain (barrier,
|
|
|
1479 barrier);
|
|
|
1480 }
|
|
|
1481 else
|
|
|
1482 {
|
|
|
1483 barrier = emit_barrier_after (BB_END (cur_bb));
|
|
|
1484 cur_bb->il.rtl->footer = unlink_insn_chain (barrier,
|
|
|
1485 barrier);
|
|
|
1486 }
|
|
|
1487 }
|
|
|
1488 }
|
|
|
1489 }
|
|
|
1490 }
|
|
|
1491 }
|
|
|
1492
|
|
|
1493 /* This function checks the destination block of a "crossing jump" to
|
|
|
1494 see if it has any crossing predecessors that begin with a code label
|
|
|
1495 and end with an unconditional jump. If so, it returns that predecessor
|
|
|
1496 block. (This is to avoid creating lots of new basic blocks that all
|
|
|
1497 contain unconditional jumps to the same destination). */
|
|
|
1498
|
|
|
1499 static basic_block
|
|
|
1500 find_jump_block (basic_block jump_dest)
|
|
|
1501 {
|
|
|
1502 basic_block source_bb = NULL;
|
|
|
1503 edge e;
|
|
|
1504 rtx insn;
|
|
|
1505 edge_iterator ei;
|
|
|
1506
|
|
|
1507 FOR_EACH_EDGE (e, ei, jump_dest->preds)
|
|
|
1508 if (e->flags & EDGE_CROSSING)
|
|
|
1509 {
|
|
|
1510 basic_block src = e->src;
|
|
|
1511
|
|
|
1512 /* Check each predecessor to see if it has a label, and contains
|
|
|
1513 only one executable instruction, which is an unconditional jump.
|
|
|
1514 If so, we can use it. */
|
|
|
1515
|
|
|
1516 if (LABEL_P (BB_HEAD (src)))
|
|
|
1517 for (insn = BB_HEAD (src);
|
|
|
1518 !INSN_P (insn) && insn != NEXT_INSN (BB_END (src));
|
|
|
1519 insn = NEXT_INSN (insn))
|
|
|
1520 {
|
|
|
1521 if (INSN_P (insn)
|
|
|
1522 && insn == BB_END (src)
|
|
|
1523 && JUMP_P (insn)
|
|
|
1524 && !any_condjump_p (insn))
|
|
|
1525 {
|
|
|
1526 source_bb = src;
|
|
|
1527 break;
|
|
|
1528 }
|
|
|
1529 }
|
|
|
1530
|
|
|
1531 if (source_bb)
|
|
|
1532 break;
|
|
|
1533 }
|
|
|
1534
|
|
|
1535 return source_bb;
|
|
|
1536 }
|
|
|
1537
|
|
|
1538 /* Find all BB's with conditional jumps that are crossing edges;
|
|
|
1539 insert a new bb and make the conditional jump branch to the new
|
|
|
1540 bb instead (make the new bb same color so conditional branch won't
|
|
|
1541 be a 'crossing' edge). Insert an unconditional jump from the
|
|
|
1542 new bb to the original destination of the conditional jump. */
|
|
|
1543
|
|
|
1544 static void
|
|
|
1545 fix_crossing_conditional_branches (void)
|
|
|
1546 {
|
|
|
1547 basic_block cur_bb;
|
|
|
1548 basic_block new_bb;
|
|
|
1549 basic_block last_bb;
|
|
|
1550 basic_block dest;
|
|
|
1551 edge succ1;
|
|
|
1552 edge succ2;
|
|
|
1553 edge crossing_edge;
|
|
|
1554 edge new_edge;
|
|
|
1555 rtx old_jump;
|
|
|
1556 rtx set_src;
|
|
|
1557 rtx old_label = NULL_RTX;
|
|
|
1558 rtx new_label;
|
|
|
1559 rtx new_jump;
|
|
|
1560 rtx barrier;
|
|
|
1561
|
|
|
1562 last_bb = EXIT_BLOCK_PTR->prev_bb;
|
|
|
1563
|
|
|
1564 FOR_EACH_BB (cur_bb)
|
|
|
1565 {
|
|
|
1566 crossing_edge = NULL;
|
|
|
1567 if (EDGE_COUNT (cur_bb->succs) > 0)
|
|
|
1568 succ1 = EDGE_SUCC (cur_bb, 0);
|
|
|
1569 else
|
|
|
1570 succ1 = NULL;
|
|
|
1571
|
|
|
1572 if (EDGE_COUNT (cur_bb->succs) > 1)
|
|
|
1573 succ2 = EDGE_SUCC (cur_bb, 1);
|
|
|
1574 else
|
|
|
1575 succ2 = NULL;
|
|
|
1576
|
|
|
1577 /* We already took care of fall-through edges, so only one successor
|
|
|
1578 can be a crossing edge. */
|
|
|
1579
|
|
|
1580 if (succ1 && (succ1->flags & EDGE_CROSSING))
|
|
|
1581 crossing_edge = succ1;
|
|
|
1582 else if (succ2 && (succ2->flags & EDGE_CROSSING))
|
|
|
1583 crossing_edge = succ2;
|
|
|
1584
|
|
|
1585 if (crossing_edge)
|
|
|
1586 {
|
|
|
1587 old_jump = BB_END (cur_bb);
|
|
|
1588
|
|
|
1589 /* Check to make sure the jump instruction is a
|
|
|
1590 conditional jump. */
|
|
|
1591
|
|
|
1592 set_src = NULL_RTX;
|
|
|
1593
|
|
|
1594 if (any_condjump_p (old_jump))
|
|
|
1595 {
|
|
|
1596 if (GET_CODE (PATTERN (old_jump)) == SET)
|
|
|
1597 set_src = SET_SRC (PATTERN (old_jump));
|
|
|
1598 else if (GET_CODE (PATTERN (old_jump)) == PARALLEL)
|
|
|
1599 {
|
|
|
1600 set_src = XVECEXP (PATTERN (old_jump), 0,0);
|
|
|
1601 if (GET_CODE (set_src) == SET)
|
|
|
1602 set_src = SET_SRC (set_src);
|
|
|
1603 else
|
|
|
1604 set_src = NULL_RTX;
|
|
|
1605 }
|
|
|
1606 }
|
|
|
1607
|
|
|
1608 if (set_src && (GET_CODE (set_src) == IF_THEN_ELSE))
|
|
|
1609 {
|
|
|
1610 if (GET_CODE (XEXP (set_src, 1)) == PC)
|
|
|
1611 old_label = XEXP (set_src, 2);
|
|
|
1612 else if (GET_CODE (XEXP (set_src, 2)) == PC)
|
|
|
1613 old_label = XEXP (set_src, 1);
|
|
|
1614
|
|
|
1615 /* Check to see if new bb for jumping to that dest has
|
|
|
1616 already been created; if so, use it; if not, create
|
|
|
1617 a new one. */
|
|
|
1618
|
|
|
1619 new_bb = find_jump_block (crossing_edge->dest);
|
|
|
1620
|
|
|
1621 if (new_bb)
|
|
|
1622 new_label = block_label (new_bb);
|
|
|
1623 else
|
|
|
1624 {
|
|
|
1625 /* Create new basic block to be dest for
|
|
|
1626 conditional jump. */
|
|
|
1627
|
|
|
1628 new_bb = create_basic_block (NULL, NULL, last_bb);
|
|
|
1629 new_bb->aux = last_bb->aux;
|
|
|
1630 last_bb->aux = new_bb;
|
|
|
1631 last_bb = new_bb;
|
|
|
1632 /* Put appropriate instructions in new bb. */
|
|
|
1633
|
|
|
1634 new_label = gen_label_rtx ();
|
|
|
1635 emit_label_before (new_label, BB_HEAD (new_bb));
|
|
|
1636 BB_HEAD (new_bb) = new_label;
|
|
|
1637
|
|
|
1638 if (GET_CODE (old_label) == LABEL_REF)
|
|
|
1639 {
|
|
|
1640 old_label = JUMP_LABEL (old_jump);
|
|
|
1641 new_jump = emit_jump_insn_after (gen_jump
|
|
|
1642 (old_label),
|
|
|
1643 BB_END (new_bb));
|
|
|
1644 }
|
|
|
1645 else
|
|
|
1646 {
|
|
|
1647 gcc_assert (HAVE_return
|
|
|
1648 && GET_CODE (old_label) == RETURN);
|
|
|
1649 new_jump = emit_jump_insn_after (gen_return (),
|
|
|
1650 BB_END (new_bb));
|
|
|
1651 }
|
|
|
1652
|
|
|
1653 barrier = emit_barrier_after (new_jump);
|
|
|
1654 JUMP_LABEL (new_jump) = old_label;
|
|
|
1655 new_bb->il.rtl->footer = unlink_insn_chain (barrier,
|
|
|
1656 barrier);
|
|
|
1657
|
|
|
1658 /* Make sure new bb is in same partition as source
|
|
|
1659 of conditional branch. */
|
|
|
1660 BB_COPY_PARTITION (new_bb, cur_bb);
|
|
|
1661 }
|
|
|
1662
|
|
|
1663 /* Make old jump branch to new bb. */
|
|
|
1664
|
|
|
1665 redirect_jump (old_jump, new_label, 0);
|
|
|
1666
|
|
|
1667 /* Remove crossing_edge as predecessor of 'dest'. */
|
|
|
1668
|
|
|
1669 dest = crossing_edge->dest;
|
|
|
1670
|
|
|
1671 redirect_edge_succ (crossing_edge, new_bb);
|
|
|
1672
|
|
|
1673 /* Make a new edge from new_bb to old dest; new edge
|
|
|
1674 will be a successor for new_bb and a predecessor
|
|
|
1675 for 'dest'. */
|
|
|
1676
|
|
|
1677 if (EDGE_COUNT (new_bb->succs) == 0)
|
|
|
1678 new_edge = make_edge (new_bb, dest, 0);
|
|
|
1679 else
|
|
|
1680 new_edge = EDGE_SUCC (new_bb, 0);
|
|
|
1681
|
|
|
1682 crossing_edge->flags &= ~EDGE_CROSSING;
|
|
|
1683 new_edge->flags |= EDGE_CROSSING;
|
|
|
1684 }
|
|
|
1685 }
|
|
|
1686 }
|
|
|
1687 }
|
|
|
1688
|
|
|
1689 /* Find any unconditional branches that cross between hot and cold
|
|
|
1690 sections. Convert them into indirect jumps instead. */
|
|
|
1691
|
|
|
1692 static void
|
|
|
1693 fix_crossing_unconditional_branches (void)
|
|
|
1694 {
|
|
|
1695 basic_block cur_bb;
|
|
|
1696 rtx last_insn;
|
|
|
1697 rtx label;
|
|
|
1698 rtx label_addr;
|
|
|
1699 rtx indirect_jump_sequence;
|
|
|
1700 rtx jump_insn = NULL_RTX;
|
|
|
1701 rtx new_reg;
|
|
|
1702 rtx cur_insn;
|
|
|
1703 edge succ;
|
|
|
1704
|
|
|
1705 FOR_EACH_BB (cur_bb)
|
|
|
1706 {
|
|
|
1707 last_insn = BB_END (cur_bb);
|
|
|
1708
|
|
|
1709 if (EDGE_COUNT (cur_bb->succs) < 1)
|
|
|
1710 continue;
|
|
|
1711
|
|
|
1712 succ = EDGE_SUCC (cur_bb, 0);
|
|
|
1713
|
|
|
1714 /* Check to see if bb ends in a crossing (unconditional) jump. At
|
|
|
1715 this point, no crossing jumps should be conditional. */
|
|
|
1716
|
|
|
1717 if (JUMP_P (last_insn)
|
|
|
1718 && (succ->flags & EDGE_CROSSING))
|
|
|
1719 {
|
|
|
1720 rtx label2, table;
|
|
|
1721
|
|
|
1722 gcc_assert (!any_condjump_p (last_insn));
|
|
|
1723
|
|
|
1724 /* Make sure the jump is not already an indirect or table jump. */
|
|
|
1725
|
|
|
1726 if (!computed_jump_p (last_insn)
|
|
|
1727 && !tablejump_p (last_insn, &label2, &table))
|
|
|
1728 {
|
|
|
1729 /* We have found a "crossing" unconditional branch. Now
|
|
|
1730 we must convert it to an indirect jump. First create
|
|
|
1731 reference of label, as target for jump. */
|
|
|
1732
|
|
|
1733 label = JUMP_LABEL (last_insn);
|
|
|
1734 label_addr = gen_rtx_LABEL_REF (Pmode, label);
|
|
|
1735 LABEL_NUSES (label) += 1;
|
|
|
1736
|
|
|
1737 /* Get a register to use for the indirect jump. */
|
|
|
1738
|
|
|
1739 new_reg = gen_reg_rtx (Pmode);
|
|
|
1740
|
|
|
1741 /* Generate indirect the jump sequence. */
|
|
|
1742
|
|
|
1743 start_sequence ();
|
|
|
1744 emit_move_insn (new_reg, label_addr);
|
|
|
1745 emit_indirect_jump (new_reg);
|
|
|
1746 indirect_jump_sequence = get_insns ();
|
|
|
1747 end_sequence ();
|
|
|
1748
|
|
|
1749 /* Make sure every instruction in the new jump sequence has
|
|
|
1750 its basic block set to be cur_bb. */
|
|
|
1751
|
|
|
1752 for (cur_insn = indirect_jump_sequence; cur_insn;
|
|
|
1753 cur_insn = NEXT_INSN (cur_insn))
|
|
|
1754 {
|
|
|
1755 if (!BARRIER_P (cur_insn))
|
|
|
1756 BLOCK_FOR_INSN (cur_insn) = cur_bb;
|
|
|
1757 if (JUMP_P (cur_insn))
|
|
|
1758 jump_insn = cur_insn;
|
|
|
1759 }
|
|
|
1760
|
|
|
1761 /* Insert the new (indirect) jump sequence immediately before
|
|
|
1762 the unconditional jump, then delete the unconditional jump. */
|
|
|
1763
|
|
|
1764 emit_insn_before (indirect_jump_sequence, last_insn);
|
|
|
1765 delete_insn (last_insn);
|
|
|
1766
|
|
|
1767 /* Make BB_END for cur_bb be the jump instruction (NOT the
|
|
|
1768 barrier instruction at the end of the sequence...). */
|
|
|
1769
|
|
|
1770 BB_END (cur_bb) = jump_insn;
|
|
|
1771 }
|
|
|
1772 }
|
|
|
1773 }
|
|
|
1774 }
|
|
|
1775
|
|
|
1776 /* Add REG_CROSSING_JUMP note to all crossing jump insns. */
|
|
|
1777
|
|
|
1778 static void
|
|
|
1779 add_reg_crossing_jump_notes (void)
|
|
|
1780 {
|
|
|
1781 basic_block bb;
|
|
|
1782 edge e;
|
|
|
1783 edge_iterator ei;
|
|
|
1784
|
|
|
1785 FOR_EACH_BB (bb)
|
|
|
1786 FOR_EACH_EDGE (e, ei, bb->succs)
|
|
|
1787 if ((e->flags & EDGE_CROSSING)
|
|
|
1788 && JUMP_P (BB_END (e->src)))
|
|
|
1789 add_reg_note (BB_END (e->src), REG_CROSSING_JUMP, NULL_RTX);
|
|
|
1790 }
|
|
|
1791
|
|
|
1792 /* Hot and cold basic blocks are partitioned and put in separate
|
|
|
1793 sections of the .o file, to reduce paging and improve cache
|
|
|
1794 performance (hopefully). This can result in bits of code from the
|
|
|
1795 same function being widely separated in the .o file. However this
|
|
|
1796 is not obvious to the current bb structure. Therefore we must take
|
|
|
1797 care to ensure that: 1). There are no fall_thru edges that cross
|
|
|
1798 between sections; 2). For those architectures which have "short"
|
|
|
1799 conditional branches, all conditional branches that attempt to
|
|
|
1800 cross between sections are converted to unconditional branches;
|
|
|
1801 and, 3). For those architectures which have "short" unconditional
|
|
|
1802 branches, all unconditional branches that attempt to cross between
|
|
|
1803 sections are converted to indirect jumps.
|
|
|
1804
|
|
|
1805 The code for fixing up fall_thru edges that cross between hot and
|
|
|
1806 cold basic blocks does so by creating new basic blocks containing
|
|
|
1807 unconditional branches to the appropriate label in the "other"
|
|
|
1808 section. The new basic block is then put in the same (hot or cold)
|
|
|
1809 section as the original conditional branch, and the fall_thru edge
|
|
|
1810 is modified to fall into the new basic block instead. By adding
|
|
|
1811 this level of indirection we end up with only unconditional branches
|
|
|
1812 crossing between hot and cold sections.
|
|
|
1813
|
|
|
1814 Conditional branches are dealt with by adding a level of indirection.
|
|
|
1815 A new basic block is added in the same (hot/cold) section as the
|
|
|
1816 conditional branch, and the conditional branch is retargeted to the
|
|
|
1817 new basic block. The new basic block contains an unconditional branch
|
|
|
1818 to the original target of the conditional branch (in the other section).
|
|
|
1819
|
|
|
1820 Unconditional branches are dealt with by converting them into
|
|
|
1821 indirect jumps. */
|
|
|
1822
|
|
|
1823 static void
|
|
|
1824 fix_edges_for_rarely_executed_code (edge *crossing_edges,
|
|
|
1825 int n_crossing_edges)
|
|
|
1826 {
|
|
|
1827 /* Make sure the source of any crossing edge ends in a jump and the
|
|
|
1828 destination of any crossing edge has a label. */
|
|
|
1829
|
|
|
1830 add_labels_and_missing_jumps (crossing_edges, n_crossing_edges);
|
|
|
1831
|
|
|
1832 /* Convert all crossing fall_thru edges to non-crossing fall
|
|
|
1833 thrus to unconditional jumps (that jump to the original fall
|
|
|
1834 thru dest). */
|
|
|
1835
|
|
|
1836 fix_up_fall_thru_edges ();
|
|
|
1837
|
|
|
1838 /* If the architecture does not have conditional branches that can
|
|
|
1839 span all of memory, convert crossing conditional branches into
|
|
|
1840 crossing unconditional branches. */
|
|
|
1841
|
|
|
1842 if (!HAS_LONG_COND_BRANCH)
|
|
|
1843 fix_crossing_conditional_branches ();
|
|
|
1844
|
|
|
1845 /* If the architecture does not have unconditional branches that
|
|
|
1846 can span all of memory, convert crossing unconditional branches
|
|
|
1847 into indirect jumps. Since adding an indirect jump also adds
|
|
|
1848 a new register usage, update the register usage information as
|
|
|
1849 well. */
|
|
|
1850
|
|
|
1851 if (!HAS_LONG_UNCOND_BRANCH)
|
|
|
1852 fix_crossing_unconditional_branches ();
|
|
|
1853
|
|
|
1854 add_reg_crossing_jump_notes ();
|
|
|
1855 }
|
|
|
1856
|
|
|
1857 /* Verify, in the basic block chain, that there is at most one switch
|
|
|
1858 between hot/cold partitions. This is modelled on
|
|
|
1859 rtl_verify_flow_info_1, but it cannot go inside that function
|
|
|
1860 because this condition will not be true until after
|
|
|
1861 reorder_basic_blocks is called. */
|
|
|
1862
|
|
|
1863 static void
|
|
|
1864 verify_hot_cold_block_grouping (void)
|
|
|
1865 {
|
|
|
1866 basic_block bb;
|
|
|
1867 int err = 0;
|
|
|
1868 bool switched_sections = false;
|
|
|
1869 int current_partition = 0;
|
|
|
1870
|
|
|
1871 FOR_EACH_BB (bb)
|
|
|
1872 {
|
|
|
1873 if (!current_partition)
|
|
|
1874 current_partition = BB_PARTITION (bb);
|
|
|
1875 if (BB_PARTITION (bb) != current_partition)
|
|
|
1876 {
|
|
|
1877 if (switched_sections)
|
|
|
1878 {
|
|
|
1879 error ("multiple hot/cold transitions found (bb %i)",
|
|
|
1880 bb->index);
|
|
|
1881 err = 1;
|
|
|
1882 }
|
|
|
1883 else
|
|
|
1884 {
|
|
|
1885 switched_sections = true;
|
|
|
1886 current_partition = BB_PARTITION (bb);
|
|
|
1887 }
|
|
|
1888 }
|
|
|
1889 }
|
|
|
1890
|
|
|
1891 gcc_assert(!err);
|
|
|
1892 }
|
|
|
1893
|
|
|
1894 /* Reorder basic blocks. The main entry point to this file. FLAGS is
|
|
|
1895 the set of flags to pass to cfg_layout_initialize(). */
|
|
|
1896
|
|
|
1897 void
|
|
|
1898 reorder_basic_blocks (void)
|
|
|
1899 {
|
|
|
1900 int n_traces;
|
|
|
1901 int i;
|
|
|
1902 struct trace *traces;
|
|
|
1903
|
|
|
1904 gcc_assert (current_ir_type () == IR_RTL_CFGLAYOUT);
|
|
|
1905
|
|
|
1906 if (n_basic_blocks <= NUM_FIXED_BLOCKS + 1)
|
|
|
1907 return;
|
|
|
1908
|
|
|
1909 set_edge_can_fallthru_flag ();
|
|
|
1910 mark_dfs_back_edges ();
|
|
|
1911
|
|
|
1912 /* We are estimating the length of uncond jump insn only once since the code
|
|
|
1913 for getting the insn length always returns the minimal length now. */
|
|
|
1914 if (uncond_jump_length == 0)
|
|
|
1915 uncond_jump_length = get_uncond_jump_length ();
|
|
|
1916
|
|
|
1917 /* We need to know some information for each basic block. */
|
|
|
1918 array_size = GET_ARRAY_SIZE (last_basic_block);
|
|
|
1919 bbd = XNEWVEC (bbro_basic_block_data, array_size);
|
|
|
1920 for (i = 0; i < array_size; i++)
|
|
|
1921 {
|
|
|
1922 bbd[i].start_of_trace = -1;
|
|
|
1923 bbd[i].in_trace = -1;
|
|
|
1924 bbd[i].end_of_trace = -1;
|
|
|
1925 bbd[i].heap = NULL;
|
|
|
1926 bbd[i].node = NULL;
|
|
|
1927 }
|
|
|
1928
|
|
|
1929 traces = XNEWVEC (struct trace, n_basic_blocks);
|
|
|
1930 n_traces = 0;
|
|
|
1931 find_traces (&n_traces, traces);
|
|
|
1932 connect_traces (n_traces, traces);
|
|
|
1933 FREE (traces);
|
|
|
1934 FREE (bbd);
|
|
|
1935
|
|
|
1936 relink_block_chain (/*stay_in_cfglayout_mode=*/true);
|
|
|
1937
|
|
|
1938 if (dump_file)
|
|
|
1939 dump_flow_info (dump_file, dump_flags);
|
|
|
1940
|
|
|
1941 if (flag_reorder_blocks_and_partition)
|
|
|
1942 verify_hot_cold_block_grouping ();
|
|
|
1943 }
|
|
|
1944
|
|
|
1945 /* Determine which partition the first basic block in the function
|
|
|
1946 belongs to, then find the first basic block in the current function
|
|
|
1947 that belongs to a different section, and insert a
|
|
|
1948 NOTE_INSN_SWITCH_TEXT_SECTIONS note immediately before it in the
|
|
|
1949 instruction stream. When writing out the assembly code,
|
|
|
1950 encountering this note will make the compiler switch between the
|
|
|
1951 hot and cold text sections. */
|
|
|
1952
|
|
|
1953 static void
|
|
|
1954 insert_section_boundary_note (void)
|
|
|
1955 {
|
|
|
1956 basic_block bb;
|
|
|
1957 rtx new_note;
|
|
|
1958 int first_partition = 0;
|
|
|
1959
|
|
|
1960 if (flag_reorder_blocks_and_partition)
|
|
|
1961 FOR_EACH_BB (bb)
|
|
|
1962 {
|
|
|
1963 if (!first_partition)
|
|
|
1964 first_partition = BB_PARTITION (bb);
|
|
|
1965 if (BB_PARTITION (bb) != first_partition)
|
|
|
1966 {
|
|
|
1967 new_note = emit_note_before (NOTE_INSN_SWITCH_TEXT_SECTIONS,
|
|
|
1968 BB_HEAD (bb));
|
|
|
1969 /* ??? This kind of note always lives between basic blocks,
|
|
|
1970 but add_insn_before will set BLOCK_FOR_INSN anyway. */
|
|
|
1971 BLOCK_FOR_INSN (new_note) = NULL;
|
|
|
1972 break;
|
|
|
1973 }
|
|
|
1974 }
|
|
|
1975 }
|
|
|
1976
|
|
|
1977 /* Duplicate the blocks containing computed gotos. This basically unfactors
|
|
|
1978 computed gotos that were factored early on in the compilation process to
|
|
|
1979 speed up edge based data flow. We used to not unfactoring them again,
|
|
|
1980 which can seriously pessimize code with many computed jumps in the source
|
|
|
1981 code, such as interpreters. See e.g. PR15242. */
|
|
|
1982
|
|
|
1983 static bool
|
|
|
1984 gate_duplicate_computed_gotos (void)
|
|
|
1985 {
|
|
|
1986 if (targetm.cannot_modify_jumps_p ())
|
|
|
1987 return false;
|
|
|
1988 return (optimize > 0 && flag_expensive_optimizations);
|
|
|
1989 }
|
|
|
1990
|
|
|
1991
|
|
|
1992 static unsigned int
|
|
|
1993 duplicate_computed_gotos (void)
|
|
|
1994 {
|
|
|
1995 basic_block bb, new_bb;
|
|
|
1996 bitmap candidates;
|
|
|
1997 int max_size;
|
|
|
1998
|
|
|
1999 if (n_basic_blocks <= NUM_FIXED_BLOCKS + 1)
|
|
|
2000 return 0;
|
|
|
2001
|
|
|
2002 cfg_layout_initialize (0);
|
|
|
2003
|
|
|
2004 /* We are estimating the length of uncond jump insn only once
|
|
|
2005 since the code for getting the insn length always returns
|
|
|
2006 the minimal length now. */
|
|
|
2007 if (uncond_jump_length == 0)
|
|
|
2008 uncond_jump_length = get_uncond_jump_length ();
|
|
|
2009
|
|
|
2010 max_size = uncond_jump_length * PARAM_VALUE (PARAM_MAX_GOTO_DUPLICATION_INSNS);
|
|
|
2011 candidates = BITMAP_ALLOC (NULL);
|
|
|
2012
|
|
|
2013 /* Look for blocks that end in a computed jump, and see if such blocks
|
|
|
2014 are suitable for unfactoring. If a block is a candidate for unfactoring,
|
|
|
2015 mark it in the candidates. */
|
|
|
2016 FOR_EACH_BB (bb)
|
|
|
2017 {
|
|
|
2018 rtx insn;
|
|
|
2019 edge e;
|
|
|
2020 edge_iterator ei;
|
|
|
2021 int size, all_flags;
|
|
|
2022
|
|
|
2023 /* Build the reorder chain for the original order of blocks. */
|
|
|
2024 if (bb->next_bb != EXIT_BLOCK_PTR)
|
|
|
2025 bb->aux = bb->next_bb;
|
|
|
2026
|
|
|
2027 /* Obviously the block has to end in a computed jump. */
|
|
|
2028 if (!computed_jump_p (BB_END (bb)))
|
|
|
2029 continue;
|
|
|
2030
|
|
|
2031 /* Only consider blocks that can be duplicated. */
|
|
|
2032 if (find_reg_note (BB_END (bb), REG_CROSSING_JUMP, NULL_RTX)
|
|
|
2033 || !can_duplicate_block_p (bb))
|
|
|
2034 continue;
|
|
|
2035
|
|
|
2036 /* Make sure that the block is small enough. */
|
|
|
2037 size = 0;
|
|
|
2038 FOR_BB_INSNS (bb, insn)
|
|
|
2039 if (INSN_P (insn))
|
|
|
2040 {
|
|
|
2041 size += get_attr_min_length (insn);
|
|
|
2042 if (size > max_size)
|
|
|
2043 break;
|
|
|
2044 }
|
|
|
2045 if (size > max_size)
|
|
|
2046 continue;
|
|
|
2047
|
|
|
2048 /* Final check: there must not be any incoming abnormal edges. */
|
|
|
2049 all_flags = 0;
|
|
|
2050 FOR_EACH_EDGE (e, ei, bb->preds)
|
|
|
2051 all_flags |= e->flags;
|
|
|
2052 if (all_flags & EDGE_COMPLEX)
|
|
|
2053 continue;
|
|
|
2054
|
|
|
2055 bitmap_set_bit (candidates, bb->index);
|
|
|
2056 }
|
|
|
2057
|
|
|
2058 /* Nothing to do if there is no computed jump here. */
|
|
|
2059 if (bitmap_empty_p (candidates))
|
|
|
2060 goto done;
|
|
|
2061
|
|
|
2062 /* Duplicate computed gotos. */
|
|
|
2063 FOR_EACH_BB (bb)
|
|
|
2064 {
|
|
|
2065 if (bb->il.rtl->visited)
|
|
|
2066 continue;
|
|
|
2067
|
|
|
2068 bb->il.rtl->visited = 1;
|
|
|
2069
|
|
|
2070 /* BB must have one outgoing edge. That edge must not lead to
|
|
|
2071 the exit block or the next block.
|
|
|
2072 The destination must have more than one predecessor. */
|
|
|
2073 if (!single_succ_p (bb)
|
|
|
2074 || single_succ (bb) == EXIT_BLOCK_PTR
|
|
|
2075 || single_succ (bb) == bb->next_bb
|
|
|
2076 || single_pred_p (single_succ (bb)))
|
|
|
2077 continue;
|
|
|
2078
|
|
|
2079 if (!optimize_bb_for_size_p (bb))
|
|
|
2080 continue;
|
|
|
2081
|
|
|
2082 /* The successor block has to be a duplication candidate. */
|
|
|
2083 if (!bitmap_bit_p (candidates, single_succ (bb)->index))
|
|
|
2084 continue;
|
|
|
2085
|
|
|
2086 new_bb = duplicate_block (single_succ (bb), single_succ_edge (bb), bb);
|
|
|
2087 new_bb->aux = bb->aux;
|
|
|
2088 bb->aux = new_bb;
|
|
|
2089 new_bb->il.rtl->visited = 1;
|
|
|
2090 }
|
|
|
2091
|
|
|
2092 done:
|
|
|
2093 cfg_layout_finalize ();
|
|
|
2094
|
|
|
2095 BITMAP_FREE (candidates);
|
|
|
2096 return 0;
|
|
|
2097 }
|
|
|
2098
|
|
|
2099 struct rtl_opt_pass pass_duplicate_computed_gotos =
|
|
|
2100 {
|
|
|
2101 {
|
|
|
2102 RTL_PASS,
|
|
|
2103 "compgotos", /* name */
|
|
|
2104 gate_duplicate_computed_gotos, /* gate */
|
|
|
2105 duplicate_computed_gotos, /* execute */
|
|
|
2106 NULL, /* sub */
|
|
|
2107 NULL, /* next */
|
|
|
2108 0, /* static_pass_number */
|
|
|
2109 TV_REORDER_BLOCKS, /* tv_id */
|
|
|
2110 0, /* properties_required */
|
|
|
2111 0, /* properties_provided */
|
|
|
2112 0, /* properties_destroyed */
|
|
|
2113 0, /* todo_flags_start */
|
|
|
2114 TODO_dump_func | TODO_verify_rtl_sharing,/* todo_flags_finish */
|
|
|
2115 }
|
|
|
2116 };
|
|
|
2117
|
|
|
2118
|
|
|
2119 /* This function is the main 'entrance' for the optimization that
|
|
|
2120 partitions hot and cold basic blocks into separate sections of the
|
|
|
2121 .o file (to improve performance and cache locality). Ideally it
|
|
|
2122 would be called after all optimizations that rearrange the CFG have
|
|
|
2123 been called. However part of this optimization may introduce new
|
|
|
2124 register usage, so it must be called before register allocation has
|
|
|
2125 occurred. This means that this optimization is actually called
|
|
|
2126 well before the optimization that reorders basic blocks (see
|
|
|
2127 function above).
|
|
|
2128
|
|
|
2129 This optimization checks the feedback information to determine
|
|
|
2130 which basic blocks are hot/cold, updates flags on the basic blocks
|
|
|
2131 to indicate which section they belong in. This information is
|
|
|
2132 later used for writing out sections in the .o file. Because hot
|
|
|
2133 and cold sections can be arbitrarily large (within the bounds of
|
|
|
2134 memory), far beyond the size of a single function, it is necessary
|
|
|
2135 to fix up all edges that cross section boundaries, to make sure the
|
|
|
2136 instructions used can actually span the required distance. The
|
|
|
2137 fixes are described below.
|
|
|
2138
|
|
|
2139 Fall-through edges must be changed into jumps; it is not safe or
|
|
|
2140 legal to fall through across a section boundary. Whenever a
|
|
|
2141 fall-through edge crossing a section boundary is encountered, a new
|
|
|
2142 basic block is inserted (in the same section as the fall-through
|
|
|
2143 source), and the fall through edge is redirected to the new basic
|
|
|
2144 block. The new basic block contains an unconditional jump to the
|
|
|
2145 original fall-through target. (If the unconditional jump is
|
|
|
2146 insufficient to cross section boundaries, that is dealt with a
|
|
|
2147 little later, see below).
|
|
|
2148
|
|
|
2149 In order to deal with architectures that have short conditional
|
|
|
2150 branches (which cannot span all of memory) we take any conditional
|
|
|
2151 jump that attempts to cross a section boundary and add a level of
|
|
|
2152 indirection: it becomes a conditional jump to a new basic block, in
|
|
|
2153 the same section. The new basic block contains an unconditional
|
|
|
2154 jump to the original target, in the other section.
|
|
|
2155
|
|
|
2156 For those architectures whose unconditional branch is also
|
|
|
2157 incapable of reaching all of memory, those unconditional jumps are
|
|
|
2158 converted into indirect jumps, through a register.
|
|
|
2159
|
|
|
2160 IMPORTANT NOTE: This optimization causes some messy interactions
|
|
|
2161 with the cfg cleanup optimizations; those optimizations want to
|
|
|
2162 merge blocks wherever possible, and to collapse indirect jump
|
|
|
2163 sequences (change "A jumps to B jumps to C" directly into "A jumps
|
|
|
2164 to C"). Those optimizations can undo the jump fixes that
|
|
|
2165 partitioning is required to make (see above), in order to ensure
|
|
|
2166 that jumps attempting to cross section boundaries are really able
|
|
|
2167 to cover whatever distance the jump requires (on many architectures
|
|
|
2168 conditional or unconditional jumps are not able to reach all of
|
|
|
2169 memory). Therefore tests have to be inserted into each such
|
|
|
2170 optimization to make sure that it does not undo stuff necessary to
|
|
|
2171 cross partition boundaries. This would be much less of a problem
|
|
|
2172 if we could perform this optimization later in the compilation, but
|
|
|
2173 unfortunately the fact that we may need to create indirect jumps
|
|
|
2174 (through registers) requires that this optimization be performed
|
|
|
2175 before register allocation. */
|
|
|
2176
|
|
|
2177 static void
|
|
|
2178 partition_hot_cold_basic_blocks (void)
|
|
|
2179 {
|
|
|
2180 basic_block cur_bb;
|
|
|
2181 edge *crossing_edges;
|
|
|
2182 int n_crossing_edges;
|
|
|
2183 int max_edges = 2 * last_basic_block;
|
|
|
2184
|
|
|
2185 if (n_basic_blocks <= NUM_FIXED_BLOCKS + 1)
|
|
|
2186 return;
|
|
|
2187
|
|
|
2188 crossing_edges = XCNEWVEC (edge, max_edges);
|
|
|
2189
|
|
|
2190 cfg_layout_initialize (0);
|
|
|
2191
|
|
|
2192 FOR_EACH_BB (cur_bb)
|
|
|
2193 if (cur_bb->index >= NUM_FIXED_BLOCKS
|
|
|
2194 && cur_bb->next_bb->index >= NUM_FIXED_BLOCKS)
|
|
|
2195 cur_bb->aux = cur_bb->next_bb;
|
|
|
2196
|
|
|
2197 find_rarely_executed_basic_blocks_and_crossing_edges (&crossing_edges,
|
|
|
2198 &n_crossing_edges,
|
|
|
2199 &max_edges);
|
|
|
2200
|
|
|
2201 if (n_crossing_edges > 0)
|
|
|
2202 fix_edges_for_rarely_executed_code (crossing_edges, n_crossing_edges);
|
|
|
2203
|
|
|
2204 free (crossing_edges);
|
|
|
2205
|
|
|
2206 cfg_layout_finalize ();
|
|
|
2207 }
|
|
|
2208
|
|
|
2209 static bool
|
|
|
2210 gate_handle_reorder_blocks (void)
|
|
|
2211 {
|
|
|
2212 if (targetm.cannot_modify_jumps_p ())
|
|
|
2213 return false;
|
|
|
2214 return (optimize > 0);
|
|
|
2215 }
|
|
|
2216
|
|
|
2217
|
|
|
2218 /* Reorder basic blocks. */
|
|
|
2219 static unsigned int
|
|
|
2220 rest_of_handle_reorder_blocks (void)
|
|
|
2221 {
|
|
|
2222 basic_block bb;
|
|
|
2223
|
|
|
2224 /* Last attempt to optimize CFG, as scheduling, peepholing and insn
|
|
|
2225 splitting possibly introduced more crossjumping opportunities. */
|
|
|
2226 cfg_layout_initialize (CLEANUP_EXPENSIVE);
|
|
|
2227
|
|
|
2228 if ((flag_reorder_blocks || flag_reorder_blocks_and_partition)
|
|
|
2229 /* Don't reorder blocks when optimizing for size because extra jump insns may
|
|
|
2230 be created; also barrier may create extra padding.
|
|
|
2231
|
|
|
2232 More correctly we should have a block reordering mode that tried to
|
|
|
2233 minimize the combined size of all the jumps. This would more or less
|
|
|
2234 automatically remove extra jumps, but would also try to use more short
|
|
|
2235 jumps instead of long jumps. */
|
|
|
2236 && optimize_function_for_speed_p (cfun))
|
|
|
2237 {
|
|
|
2238 reorder_basic_blocks ();
|
|
|
2239 cleanup_cfg (CLEANUP_EXPENSIVE);
|
|
|
2240 }
|
|
|
2241
|
|
|
2242 FOR_EACH_BB (bb)
|
|
|
2243 if (bb->next_bb != EXIT_BLOCK_PTR)
|
|
|
2244 bb->aux = bb->next_bb;
|
|
|
2245 cfg_layout_finalize ();
|
|
|
2246
|
|
|
2247 /* Add NOTE_INSN_SWITCH_TEXT_SECTIONS notes. */
|
|
|
2248 insert_section_boundary_note ();
|
|
|
2249 return 0;
|
|
|
2250 }
|
|
|
2251
|
|
|
2252 struct rtl_opt_pass pass_reorder_blocks =
|
|
|
2253 {
|
|
|
2254 {
|
|
|
2255 RTL_PASS,
|
|
|
2256 "bbro", /* name */
|
|
|
2257 gate_handle_reorder_blocks, /* gate */
|
|
|
2258 rest_of_handle_reorder_blocks, /* execute */
|
|
|
2259 NULL, /* sub */
|
|
|
2260 NULL, /* next */
|
|
|
2261 0, /* static_pass_number */
|
|
|
2262 TV_REORDER_BLOCKS, /* tv_id */
|
|
|
2263 0, /* properties_required */
|
|
|
2264 0, /* properties_provided */
|
|
|
2265 0, /* properties_destroyed */
|
|
|
2266 0, /* todo_flags_start */
|
|
|
2267 TODO_dump_func | TODO_verify_rtl_sharing,/* todo_flags_finish */
|
|
|
2268 }
|
|
|
2269 };
|
|
|
2270
|
|
|
2271 static bool
|
|
|
2272 gate_handle_partition_blocks (void)
|
|
|
2273 {
|
|
|
2274 /* The optimization to partition hot/cold basic blocks into separate
|
|
|
2275 sections of the .o file does not work well with linkonce or with
|
|
|
2276 user defined section attributes. Don't call it if either case
|
|
|
2277 arises. */
|
|
|
2278
|
|
|
2279 return (flag_reorder_blocks_and_partition
|
|
|
2280 && !DECL_ONE_ONLY (current_function_decl)
|
|
|
2281 && !user_defined_section_attribute);
|
|
|
2282 }
|
|
|
2283
|
|
|
2284 /* Partition hot and cold basic blocks. */
|
|
|
2285 static unsigned int
|
|
|
2286 rest_of_handle_partition_blocks (void)
|
|
|
2287 {
|
|
|
2288 partition_hot_cold_basic_blocks ();
|
|
|
2289 return 0;
|
|
|
2290 }
|
|
|
2291
|
|
|
2292 struct rtl_opt_pass pass_partition_blocks =
|
|
|
2293 {
|
|
|
2294 {
|
|
|
2295 RTL_PASS,
|
|
|
2296 "bbpart", /* name */
|
|
|
2297 gate_handle_partition_blocks, /* gate */
|
|
|
2298 rest_of_handle_partition_blocks, /* execute */
|
|
|
2299 NULL, /* sub */
|
|
|
2300 NULL, /* next */
|
|
|
2301 0, /* static_pass_number */
|
|
|
2302 TV_REORDER_BLOCKS, /* tv_id */
|
|
|
2303 0, /* properties_required */
|
|
|
2304 0, /* properties_provided */
|
|
|
2305 0, /* properties_destroyed */
|
|
|
2306 0, /* todo_flags_start */
|
|
|
2307 TODO_dump_func | TODO_verify_rtl_sharing/* todo_flags_finish */
|
|
|
2308 }
|
|
|
2309 };
|
|
|
2310
|
|
|
2311
|
