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131
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1 /* Early (pre-RA) rematerialization
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145
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2 Copyright (C) 2017-2020 Free Software Foundation, Inc.
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131
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3
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4 This file is part of GCC.
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5
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6 GCC is free software; you can redistribute it and/or modify it under
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7 the terms of the GNU General Public License as published by the Free
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8 Software Foundation; either version 3, or (at your option) any later
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9 version.
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10
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11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
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13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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14 for more details.
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15
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16 You should have received a copy of the GNU General Public License
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17 along with GCC; see the file COPYING3. If not see
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18 <http://www.gnu.org/licenses/>. */
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19
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20 #include "config.h"
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21 #include "system.h"
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22 #include "coretypes.h"
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23 #include "backend.h"
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24 #include "rtl.h"
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25 #include "df.h"
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26 #include "tree-pass.h"
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27 #include "memmodel.h"
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28 #include "emit-rtl.h"
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29 #include "insn-config.h"
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30 #include "recog.h"
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31 /* FIXME: The next two are only needed for gen_move_insn. */
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32 #include "tree.h"
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33 #include "expr.h"
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34 #include "target.h"
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35 #include "inchash.h"
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36 #include "rtlhash.h"
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37 #include "print-rtl.h"
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38 #include "rtl-iter.h"
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145
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39 #include "regs.h"
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40 #include "function-abi.h"
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131
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41
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42 /* This pass runs before register allocation and implements an aggressive
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43 form of rematerialization. It looks for pseudo registers R of mode M
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44 for which:
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45
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46 (a) there are no call-preserved registers of mode M; and
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47 (b) spilling R to the stack is expensive.
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48
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49 The assumption is that it's better to recompute R after each call instead
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50 of spilling it, even if this extends the live ranges of other registers.
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51
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52 The motivating example for which these conditions hold are AArch64 SVE
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53 vectors and predicates. Spilling them to the stack makes the frame
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54 variable-sized, which we'd like to avoid if possible. It's also very
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55 rare for SVE values to be "naturally" live across a call: usually this
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56 happens as a result of CSE or other code motion.
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57
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58 The pass is split into the following phases:
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59
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60 Collection phase
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61 ================
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62
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63 First we go through all pseudo registers looking for any that meet
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64 the conditions above. For each such register R, we go through each
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65 instruction that defines R to see whether any of them are suitable
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66 rematerialization candidates. If at least one is, we treat all the
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67 instructions that define R as candidates, but record which ones are
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68 not in fact suitable. These unsuitable candidates exist only for the
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69 sake of calculating reaching definitions (see below).
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70
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71 A "candidate" is a single instruction that we want to rematerialize
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72 and a "candidate register" is a register that is set by at least one
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73 candidate.
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74
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75 Candidate sorting
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76 =================
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77
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78 Next we sort the candidates based on the cfg postorder, so that if
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79 candidate C1 uses candidate C2, C1 has a lower index than C2.
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80 This is useful when iterating through candidate bitmaps.
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81
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82 Reaching definition calculation
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83 ===============================
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84
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85 We then compute standard reaching-definition sets for each candidate.
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86 Each set specifies which candidates might provide the current definition
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87 of a live candidate register.
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88
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89 From here on, a candidate C is "live" at a point P if the candidate
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90 register defined by C is live at P and if C's definition reaches P.
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91 An instruction I "uses" a candidate C if I takes the register defined by
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92 C as input and if C is one of the reaching definitions of that register.
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93
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94 Candidate validation and value numbering
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95 ========================================
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96
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97 Next we simultaneously decide which candidates are valid and look
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98 for candidates that are equivalent to each other, assigning numbers
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99 to each unique candidate value. A candidate C is invalid if:
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100
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101 (a) C uses an invalid candidate;
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102
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103 (b) there is a cycle of candidate uses involving C; or
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104
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105 (c) C takes a candidate register R as input and the reaching
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106 definitions of R do not have the same value number.
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107
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108 We assign a "representative" candidate C to each value number and from
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109 here on replace references to other candidates with that value number
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110 with references to C. It is then only possible to rematerialize a
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111 register R at point P if (after this replacement) there is a single
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112 reaching definition of R at P.
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113
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114 Local phase
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115 ===========
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116
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117 During this phase we go through each block and look for cases in which:
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118
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119 (a) an instruction I comes between two call instructions CI1 and CI2;
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120
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121 (b) I uses a candidate register R;
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122
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123 (c) a candidate C provides the only reaching definition of R; and
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124
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125 (d) C does not come between CI1 and I.
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126
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127 We then emit a copy of C after CI1, as well as the transitive closure
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128 TC of the candidates used by C. The copies of TC might use the original
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129 candidate registers or new temporary registers, depending on circumstances.
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130
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131 For example, if elsewhere we have:
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132
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133 C3: R3 <- f3 (...)
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134 ...
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135 C2: R2 <- f2 (...)
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136 ...
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137 C1: R1 <- f1 (R2, R3, ...) // uses C2 and C3
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138
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139 then for a block containing:
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140
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141 CI1: call
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142 ...
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143 I: use R1 // uses C1
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144 ...
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145 CI2: call
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146
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147 we would emit:
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148
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149 CI1: call
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150 C3': R3' <- f3 (...)
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151 C2': R2' <- f2 (...)
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152 C1': R1 <- f1 (R2', R3', ...)
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153 ...
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154 I: use R1
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155 ...
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156 CI2: call
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157
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158 where R2' and R3' might be fresh registers. If instead we had:
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159
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160 CI1: call
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161 ...
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162 I1: use R1 // uses C1
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163 ...
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164 I2: use R3 // uses C3
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165 ...
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166 CI2: call
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167
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168 we would keep the original R3:
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169
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170 CI1: call
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171 C3': R3 <- f3 (...)
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172 C2': R2' <- f2 (...)
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173 C1': R1 <- f1 (R2', R3, ...)
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174 ...
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175 I1: use R1 // uses C1
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176 ...
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177 I2: use R3 // uses C3
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178 ...
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179 CI2: call
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180
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181 We also record the last call in each block (if any) and compute:
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182
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183 rd_after_call:
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184 The set of candidates that either (a) are defined outside the block
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185 and are live after the last call or (b) are defined within the block
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186 and reach the end of the last call. (We don't track whether the
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187 latter values are live or not.)
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188
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189 required_after_call:
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190 The set of candidates that need to be rematerialized after the
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191 last call in order to satisfy uses in the block itself.
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192
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193 required_in:
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194 The set of candidates that are live on entry to the block and are
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195 used without an intervening call.
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196
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197 In addition, we compute the initial values of the sets required by
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198 the global phase below.
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199
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200 Global phase
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201 ============
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202
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203 We next compute a maximal solution to the following availability
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204 problem:
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205
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206 available_in:
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207 The set of candidates that are live on entry to a block and can
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208 be used at that point without rematerialization.
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209
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210 available_out:
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211 The set of candidates that are live on exit from a block and can
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212 be used at that point without rematerialization.
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213
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214 available_locally:
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215 The subset of available_out that is due to code in the block itself.
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216 It contains candidates that are defined or used in the block and
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217 not invalidated by a later call.
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218
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219 We then go through each block B and look for an appropriate place
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220 to insert copies of required_in - available_in. Conceptually we
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221 start by placing the copies at the head of B, but then move the
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222 copy of a candidate C to predecessors if:
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223
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224 (a) that seems cheaper;
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225
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226 (b) there is more than one reaching definition of C's register at
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227 the head of B; or
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228
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229 (c) copying C would clobber a hard register that is live on entry to B.
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230
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231 Moving a copy of C to a predecessor block PB involves:
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232
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233 (1) adding C to PB's required_after_call, if PB contains a call; or
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234
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235 (2) adding C PB's required_in otherwise.
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236
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237 C is then available on output from each PB and on input to B.
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238
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239 Once all this is done, we emit instructions for the final required_in
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240 and required_after_call sets. */
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241
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242 namespace {
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243
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244 /* An invalid candidate index, used to indicate that there is more than
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245 one reaching definition. */
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246 const unsigned int MULTIPLE_CANDIDATES = -1U;
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247
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248 /* Pass-specific information about one basic block. */
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249 struct remat_block_info {
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250 /* The last call instruction in the block. */
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251 rtx_insn *last_call;
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252
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253 /* The set of candidates that are live on entry to the block. NULL is
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254 equivalent to an empty set. */
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255 bitmap rd_in;
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256
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257 /* The set of candidates that are live on exit from the block. This might
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258 reuse rd_in. NULL is equivalent to an empty set. */
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259 bitmap rd_out;
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260
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261 /* The subset of RD_OUT that comes from local definitions. NULL is
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262 equivalent to an empty set. */
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263 bitmap rd_gen;
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264
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265 /* The set of candidates that the block invalidates (because it defines
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266 the register to something else, or because the register's value is
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267 no longer important). NULL is equivalent to an empty set. */
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268 bitmap rd_kill;
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269
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270 /* The set of candidates that either (a) are defined outside the block
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271 and are live after LAST_CALL or (b) are defined within the block
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272 and reach the instruction after LAST_CALL. (We don't track whether
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273 the latter values are live or not.)
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274
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275 Only used if LAST_CALL is nonnull. NULL is equivalent to an
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276 empty set. */
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277 bitmap rd_after_call;
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278
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279 /* Candidates that are live and available without rematerialization
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280 on entry to the block. NULL is equivalent to an empty set. */
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281 bitmap available_in;
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282
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283 /* Candidates that become available without rematerialization within the
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284 block, and remain so on exit. NULL is equivalent to an empty set. */
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285 bitmap available_locally;
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286
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287 /* Candidates that are available without rematerialization on exit from
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288 the block. This might reuse available_in or available_locally. */
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289 bitmap available_out;
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290
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291 /* Candidates that need to be rematerialized either at the start of the
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292 block or before entering the block. */
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293 bitmap required_in;
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294
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295 /* Candidates that need to be rematerialized after LAST_CALL.
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296 Only used if LAST_CALL is nonnull. */
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297 bitmap required_after_call;
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298
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299 /* The number of candidates in the block. */
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300 unsigned int num_candidates;
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301
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302 /* The earliest candidate in the block (i.e. the one with the
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303 highest index). Only valid if NUM_CANDIDATES is nonzero. */
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304 unsigned int first_candidate;
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305
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306 /* The best (lowest) execution frequency for rematerializing REQUIRED_IN.
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307 This is the execution frequency of the block if LOCAL_REMAT_CHEAPER_P,
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308 otherwise it is the sum of the execution frequencies of whichever
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309 predecessor blocks would do the rematerialization. */
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310 int remat_frequency;
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311
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312 /* True if the block ends with an abnormal call. */
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313 unsigned int abnormal_call_p : 1;
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314
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315 /* Used to record whether a graph traversal has visited this block. */
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316 unsigned int visited_p : 1;
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317
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318 /* True if we have calculated REMAT_FREQUENCY. */
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319 unsigned int remat_frequency_valid_p : 1;
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320
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321 /* True if it is cheaper to rematerialize candidates at the start of
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322 the block, rather than moving them to predecessor blocks. */
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323 unsigned int local_remat_cheaper_p : 1;
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324 };
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325
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326 /* Information about a group of candidates with the same value number. */
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327 struct remat_equiv_class {
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328 /* The candidates that have the same value number. */
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329 bitmap members;
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330
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331 /* The candidate that was first added to MEMBERS. */
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332 unsigned int earliest;
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333
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334 /* The candidate that represents the others. This is always the one
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335 with the highest index. */
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336 unsigned int representative;
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337 };
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338
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339 /* Information about an instruction that we might want to rematerialize. */
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340 struct remat_candidate {
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341 /* The pseudo register that the instruction sets. */
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342 unsigned int regno;
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343
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344 /* A temporary register used when rematerializing uses of this candidate,
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345 if REGNO doesn't have the right value or isn't worth using. */
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346 unsigned int copy_regno;
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347
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348 /* True if we intend to rematerialize this instruction by emitting
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349 a move of a constant into REGNO, false if we intend to emit a
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350 copy of the original instruction. */
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351 unsigned int constant_p : 1;
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352
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353 /* True if we still think it's possible to rematerialize INSN. */
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354 unsigned int can_copy_p : 1;
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355
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356 /* Used to record whether a graph traversal has visited this candidate. */
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357 unsigned int visited_p : 1;
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358
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359 /* True if we have verified that it's possible to rematerialize INSN.
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360 Once this is true, both it and CAN_COPY_P remain true. */
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361 unsigned int validated_p : 1;
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362
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363 /* True if we have "stabilized" INSN, i.e. ensured that all non-candidate
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364 registers read by INSN will have the same value when rematerializing INSN.
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365 Only ever true if CAN_COPY_P. */
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366 unsigned int stabilized_p : 1;
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367
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368 /* Hash value used for value numbering. */
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369 hashval_t hash;
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370
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371 /* The instruction that sets REGNO. */
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372 rtx_insn *insn;
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373
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374 /* If CONSTANT_P, the value that should be moved into REGNO when
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375 rematerializing, otherwise the pattern of the instruction that
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376 should be used. */
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377 rtx remat_rtx;
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378
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379 /* The set of candidates that INSN takes as input. NULL is equivalent
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380 to the empty set. All candidates in this set have a higher index
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381 than the current candidate. */
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382 bitmap uses;
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383
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384 /* The set of hard registers that would be clobbered by rematerializing
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385 the candidate, including (transitively) all those that would be
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386 clobbered by rematerializing USES. */
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387 bitmap clobbers;
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388
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389 /* The equivalence class to which the candidate belongs, or null if none. */
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390 remat_equiv_class *equiv_class;
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391 };
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392
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393 /* Hash functions used for value numbering. */
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394 struct remat_candidate_hasher : nofree_ptr_hash <remat_candidate>
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395 {
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396 typedef value_type compare_type;
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397 static hashval_t hash (const remat_candidate *);
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398 static bool equal (const remat_candidate *, const remat_candidate *);
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399 };
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400
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401 /* Main class for this pass. */
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402 class early_remat {
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403 public:
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404 early_remat (function *, sbitmap);
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405 ~early_remat ();
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406
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407 void run (void);
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408
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409 private:
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410 bitmap alloc_bitmap (void);
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411 bitmap get_bitmap (bitmap *);
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412 void init_temp_bitmap (bitmap *);
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413 void copy_temp_bitmap (bitmap *, bitmap *);
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414
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415 void dump_insn_id (rtx_insn *);
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416 void dump_candidate_bitmap (bitmap);
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417 void dump_all_candidates (void);
|
|
|
418 void dump_edge_list (basic_block, bool);
|
|
|
419 void dump_block_info (basic_block);
|
|
|
420 void dump_all_blocks (void);
|
|
|
421
|
|
|
422 bool interesting_regno_p (unsigned int);
|
|
|
423 remat_candidate *add_candidate (rtx_insn *, unsigned int, bool);
|
|
|
424 bool maybe_add_candidate (rtx_insn *, unsigned int);
|
|
|
425 bool collect_candidates (void);
|
|
|
426 void init_block_info (void);
|
|
|
427 void sort_candidates (void);
|
|
|
428 void finalize_candidate_indices (void);
|
|
|
429 void record_equiv_candidates (unsigned int, unsigned int);
|
|
|
430 static bool rd_confluence_n (edge);
|
|
|
431 static bool rd_transfer (int);
|
|
|
432 void compute_rd (void);
|
|
|
433 unsigned int canon_candidate (unsigned int);
|
|
|
434 void canon_bitmap (bitmap *);
|
|
|
435 unsigned int resolve_reaching_def (bitmap);
|
|
|
436 bool check_candidate_uses (unsigned int);
|
|
|
437 void compute_clobbers (unsigned int);
|
|
|
438 void assign_value_number (unsigned int);
|
|
|
439 void decide_candidate_validity (void);
|
|
145
|
440 void restrict_remat_for_unavail_regs (bitmap, const_bitmap);
|
|
|
441 void restrict_remat_for_call (bitmap, rtx_insn *);
|
|
131
|
442 bool stable_use_p (unsigned int);
|
|
|
443 void emit_copy_before (unsigned int, rtx, rtx);
|
|
|
444 void stabilize_pattern (unsigned int);
|
|
|
445 void replace_dest_with_copy (unsigned int);
|
|
|
446 void stabilize_candidate_uses (unsigned int, bitmap, bitmap, bitmap,
|
|
|
447 bitmap);
|
|
|
448 void emit_remat_insns (bitmap, bitmap, bitmap, rtx_insn *);
|
|
|
449 bool set_available_out (remat_block_info *);
|
|
|
450 void process_block (basic_block);
|
|
|
451 void local_phase (void);
|
|
|
452 static bool avail_confluence_n (edge);
|
|
|
453 static bool avail_transfer (int);
|
|
|
454 void compute_availability (void);
|
|
|
455 void unshare_available_sets (remat_block_info *);
|
|
|
456 bool can_move_across_edge_p (edge);
|
|
|
457 bool local_remat_cheaper_p (unsigned int);
|
|
|
458 bool need_to_move_candidate_p (unsigned int, unsigned int);
|
|
|
459 void compute_minimum_move_set (unsigned int, bitmap);
|
|
|
460 void move_to_predecessors (unsigned int, bitmap, bitmap);
|
|
|
461 void choose_rematerialization_points (void);
|
|
|
462 void emit_remat_insns_for_block (basic_block);
|
|
|
463 void global_phase (void);
|
|
|
464
|
|
|
465 /* The function that we're optimizing. */
|
|
|
466 function *m_fn;
|
|
|
467
|
|
|
468 /* The modes that we want to rematerialize. */
|
|
|
469 sbitmap m_selected_modes;
|
|
|
470
|
|
|
471 /* All rematerialization candidates, identified by their index into the
|
|
|
472 vector. */
|
|
|
473 auto_vec<remat_candidate> m_candidates;
|
|
|
474
|
|
|
475 /* The set of candidate registers. */
|
|
|
476 bitmap_head m_candidate_regnos;
|
|
|
477
|
|
|
478 /* Temporary sets. */
|
|
|
479 bitmap_head m_tmp_bitmap;
|
|
|
480 bitmap m_available;
|
|
|
481 bitmap m_required;
|
|
|
482
|
|
|
483 /* Information about each basic block. */
|
|
|
484 auto_vec<remat_block_info> m_block_info;
|
|
|
485
|
|
|
486 /* A mapping from register numbers to the set of associated candidates.
|
|
|
487 Only valid for registers in M_CANDIDATE_REGNOS. */
|
|
|
488 auto_vec<bitmap> m_regno_to_candidates;
|
|
|
489
|
|
|
490 /* An obstack used for allocating bitmaps, so that we can free them all
|
|
|
491 in one go. */
|
|
|
492 bitmap_obstack m_obstack;
|
|
|
493
|
|
|
494 /* A hash table of candidates used for value numbering. If a candidate
|
|
|
495 in the table is in an equivalence class, the candidate is marked as
|
|
|
496 the earliest member of the class. */
|
|
|
497 hash_table<remat_candidate_hasher> m_value_table;
|
|
|
498
|
|
|
499 /* Used temporarily by callback functions. */
|
|
|
500 static early_remat *er;
|
|
|
501 };
|
|
|
502
|
|
|
503 }
|
|
|
504
|
|
|
505 early_remat *early_remat::er;
|
|
|
506
|
|
|
507 /* rtx_equal_p_cb callback that treats any two SCRATCHes as equal.
|
|
|
508 This allows us to compare two copies of a pattern, even though their
|
|
|
509 SCRATCHes are always distinct. */
|
|
|
510
|
|
|
511 static int
|
|
|
512 scratch_equal (const_rtx *x, const_rtx *y, rtx *nx, rtx *ny)
|
|
|
513 {
|
|
|
514 if (GET_CODE (*x) == SCRATCH && GET_CODE (*y) == SCRATCH)
|
|
|
515 {
|
|
|
516 *nx = const0_rtx;
|
|
|
517 *ny = const0_rtx;
|
|
|
518 return 1;
|
|
|
519 }
|
|
|
520 return 0;
|
|
|
521 }
|
|
|
522
|
|
|
523 /* Hash callback functions for remat_candidate. */
|
|
|
524
|
|
|
525 hashval_t
|
|
|
526 remat_candidate_hasher::hash (const remat_candidate *cand)
|
|
|
527 {
|
|
|
528 return cand->hash;
|
|
|
529 }
|
|
|
530
|
|
|
531 bool
|
|
|
532 remat_candidate_hasher::equal (const remat_candidate *cand1,
|
|
|
533 const remat_candidate *cand2)
|
|
|
534 {
|
|
|
535 return (cand1->regno == cand2->regno
|
|
|
536 && cand1->constant_p == cand2->constant_p
|
|
|
537 && (cand1->constant_p
|
|
|
538 ? rtx_equal_p (cand1->remat_rtx, cand2->remat_rtx)
|
|
|
539 : rtx_equal_p_cb (cand1->remat_rtx, cand2->remat_rtx,
|
|
|
540 scratch_equal))
|
|
|
541 && (!cand1->uses || bitmap_equal_p (cand1->uses, cand2->uses)));
|
|
|
542 }
|
|
|
543
|
|
|
544 /* Return true if B is null or empty. */
|
|
|
545
|
|
|
546 inline bool
|
|
|
547 empty_p (bitmap b)
|
|
|
548 {
|
|
|
549 return !b || bitmap_empty_p (b);
|
|
|
550 }
|
|
|
551
|
|
|
552 /* Allocate a new bitmap. It will be automatically freed at the end of
|
|
|
553 the pass. */
|
|
|
554
|
|
|
555 inline bitmap
|
|
|
556 early_remat::alloc_bitmap (void)
|
|
|
557 {
|
|
|
558 return bitmap_alloc (&m_obstack);
|
|
|
559 }
|
|
|
560
|
|
|
561 /* Initialize *PTR to an empty bitmap if it is currently null. */
|
|
|
562
|
|
|
563 inline bitmap
|
|
|
564 early_remat::get_bitmap (bitmap *ptr)
|
|
|
565 {
|
|
|
566 if (!*ptr)
|
|
|
567 *ptr = alloc_bitmap ();
|
|
|
568 return *ptr;
|
|
|
569 }
|
|
|
570
|
|
|
571 /* *PTR is either null or empty. If it is null, initialize it to an
|
|
|
572 empty bitmap. */
|
|
|
573
|
|
|
574 inline void
|
|
|
575 early_remat::init_temp_bitmap (bitmap *ptr)
|
|
|
576 {
|
|
|
577 if (!*ptr)
|
|
|
578 *ptr = alloc_bitmap ();
|
|
|
579 else
|
|
|
580 gcc_checking_assert (bitmap_empty_p (*ptr));
|
|
|
581 }
|
|
|
582
|
|
|
583 /* Move *SRC to *DEST and leave *SRC empty. */
|
|
|
584
|
|
|
585 inline void
|
|
|
586 early_remat::copy_temp_bitmap (bitmap *dest, bitmap *src)
|
|
|
587 {
|
|
|
588 if (!empty_p (*src))
|
|
|
589 {
|
|
|
590 *dest = *src;
|
|
|
591 *src = NULL;
|
|
|
592 }
|
|
|
593 else
|
|
|
594 *dest = NULL;
|
|
|
595 }
|
|
|
596
|
|
|
597 /* Print INSN's identifier to the dump file. */
|
|
|
598
|
|
|
599 void
|
|
|
600 early_remat::dump_insn_id (rtx_insn *insn)
|
|
|
601 {
|
|
|
602 fprintf (dump_file, "%d[bb:%d]", INSN_UID (insn),
|
|
|
603 BLOCK_FOR_INSN (insn)->index);
|
|
|
604 }
|
|
|
605
|
|
|
606 /* Print candidate set CANDIDATES to the dump file, with a leading space. */
|
|
|
607
|
|
|
608 void
|
|
|
609 early_remat::dump_candidate_bitmap (bitmap candidates)
|
|
|
610 {
|
|
|
611 if (empty_p (candidates))
|
|
|
612 {
|
|
|
613 fprintf (dump_file, " none");
|
|
|
614 return;
|
|
|
615 }
|
|
|
616
|
|
|
617 unsigned int cand_index;
|
|
|
618 bitmap_iterator bi;
|
|
|
619 EXECUTE_IF_SET_IN_BITMAP (candidates, 0, cand_index, bi)
|
|
|
620 fprintf (dump_file, " %d", cand_index);
|
|
|
621 }
|
|
|
622
|
|
|
623 /* Print information about all candidates to the dump file. */
|
|
|
624
|
|
|
625 void
|
|
|
626 early_remat::dump_all_candidates (void)
|
|
|
627 {
|
|
|
628 fprintf (dump_file, "\n;; Candidates:\n;;\n");
|
|
|
629 fprintf (dump_file, ";; %5s %5s %8s %s\n", "#", "reg", "mode", "insn");
|
|
|
630 fprintf (dump_file, ";; %5s %5s %8s %s\n", "=", "===", "====", "====");
|
|
|
631 unsigned int cand_index;
|
|
|
632 remat_candidate *cand;
|
|
|
633 FOR_EACH_VEC_ELT (m_candidates, cand_index, cand)
|
|
|
634 {
|
|
|
635 fprintf (dump_file, ";; %5d %5d %8s ", cand_index, cand->regno,
|
|
|
636 GET_MODE_NAME (GET_MODE (regno_reg_rtx[cand->regno])));
|
|
|
637 dump_insn_id (cand->insn);
|
|
|
638 if (!cand->can_copy_p)
|
|
|
639 fprintf (dump_file, " -- can't copy");
|
|
|
640 fprintf (dump_file, "\n");
|
|
|
641 }
|
|
|
642
|
|
|
643 fprintf (dump_file, "\n;; Register-to-candidate mapping:\n;;\n");
|
|
|
644 unsigned int regno;
|
|
|
645 bitmap_iterator bi;
|
|
|
646 EXECUTE_IF_SET_IN_BITMAP (&m_candidate_regnos, 0, regno, bi)
|
|
|
647 {
|
|
|
648 fprintf (dump_file, ";; %5d:", regno);
|
|
|
649 dump_candidate_bitmap (m_regno_to_candidates[regno]);
|
|
|
650 fprintf (dump_file, "\n");
|
|
|
651 }
|
|
|
652 }
|
|
|
653
|
|
|
654 /* Print the predecessors or successors of BB to the dump file, with a
|
|
|
655 leading space. DO_SUCC is true to print successors and false to print
|
|
|
656 predecessors. */
|
|
|
657
|
|
|
658 void
|
|
|
659 early_remat::dump_edge_list (basic_block bb, bool do_succ)
|
|
|
660 {
|
|
|
661 edge e;
|
|
|
662 edge_iterator ei;
|
|
|
663 FOR_EACH_EDGE (e, ei, do_succ ? bb->succs : bb->preds)
|
|
|
664 dump_edge_info (dump_file, e, TDF_NONE, do_succ);
|
|
|
665 }
|
|
|
666
|
|
|
667 /* Print information about basic block BB to the dump file. */
|
|
|
668
|
|
|
669 void
|
|
|
670 early_remat::dump_block_info (basic_block bb)
|
|
|
671 {
|
|
|
672 remat_block_info *info = &m_block_info[bb->index];
|
|
|
673 fprintf (dump_file, ";;\n;; Block %d:", bb->index);
|
|
|
674 int width = 25;
|
|
|
675
|
|
|
676 fprintf (dump_file, "\n;;%*s:", width, "predecessors");
|
|
|
677 dump_edge_list (bb, false);
|
|
|
678
|
|
|
679 fprintf (dump_file, "\n;;%*s:", width, "successors");
|
|
|
680 dump_edge_list (bb, true);
|
|
|
681
|
|
|
682 fprintf (dump_file, "\n;;%*s: %d", width, "frequency",
|
|
|
683 bb->count.to_frequency (m_fn));
|
|
|
684
|
|
|
685 if (info->last_call)
|
|
|
686 fprintf (dump_file, "\n;;%*s: %d", width, "last call",
|
|
|
687 INSN_UID (info->last_call));
|
|
|
688
|
|
|
689 if (!empty_p (info->rd_in))
|
|
|
690 {
|
|
|
691 fprintf (dump_file, "\n;;%*s:", width, "RD in");
|
|
|
692 dump_candidate_bitmap (info->rd_in);
|
|
|
693 }
|
|
|
694 if (!empty_p (info->rd_kill))
|
|
|
695 {
|
|
|
696 fprintf (dump_file, "\n;;%*s:", width, "RD kill");
|
|
|
697 dump_candidate_bitmap (info->rd_kill);
|
|
|
698 }
|
|
|
699 if (!empty_p (info->rd_gen))
|
|
|
700 {
|
|
|
701 fprintf (dump_file, "\n;;%*s:", width, "RD gen");
|
|
|
702 dump_candidate_bitmap (info->rd_gen);
|
|
|
703 }
|
|
|
704 if (!empty_p (info->rd_after_call))
|
|
|
705 {
|
|
|
706 fprintf (dump_file, "\n;;%*s:", width, "RD after call");
|
|
|
707 dump_candidate_bitmap (info->rd_after_call);
|
|
|
708 }
|
|
|
709 if (!empty_p (info->rd_out))
|
|
|
710 {
|
|
|
711 fprintf (dump_file, "\n;;%*s:", width, "RD out");
|
|
|
712 if (info->rd_in == info->rd_out)
|
|
|
713 fprintf (dump_file, " RD in");
|
|
|
714 else
|
|
|
715 dump_candidate_bitmap (info->rd_out);
|
|
|
716 }
|
|
|
717 if (!empty_p (info->available_in))
|
|
|
718 {
|
|
|
719 fprintf (dump_file, "\n;;%*s:", width, "available in");
|
|
|
720 dump_candidate_bitmap (info->available_in);
|
|
|
721 }
|
|
|
722 if (!empty_p (info->available_locally))
|
|
|
723 {
|
|
|
724 fprintf (dump_file, "\n;;%*s:", width, "available locally");
|
|
|
725 dump_candidate_bitmap (info->available_locally);
|
|
|
726 }
|
|
|
727 if (!empty_p (info->available_out))
|
|
|
728 {
|
|
|
729 fprintf (dump_file, "\n;;%*s:", width, "available out");
|
|
|
730 if (info->available_in == info->available_out)
|
|
|
731 fprintf (dump_file, " available in");
|
|
|
732 else if (info->available_locally == info->available_out)
|
|
|
733 fprintf (dump_file, " available locally");
|
|
|
734 else
|
|
|
735 dump_candidate_bitmap (info->available_out);
|
|
|
736 }
|
|
|
737 if (!empty_p (info->required_in))
|
|
|
738 {
|
|
|
739 fprintf (dump_file, "\n;;%*s:", width, "required in");
|
|
|
740 dump_candidate_bitmap (info->required_in);
|
|
|
741 }
|
|
|
742 if (!empty_p (info->required_after_call))
|
|
|
743 {
|
|
|
744 fprintf (dump_file, "\n;;%*s:", width, "required after call");
|
|
|
745 dump_candidate_bitmap (info->required_after_call);
|
|
|
746 }
|
|
|
747 fprintf (dump_file, "\n");
|
|
|
748 }
|
|
|
749
|
|
|
750 /* Print information about all basic blocks to the dump file. */
|
|
|
751
|
|
|
752 void
|
|
|
753 early_remat::dump_all_blocks (void)
|
|
|
754 {
|
|
|
755 basic_block bb;
|
|
|
756 FOR_EACH_BB_FN (bb, m_fn)
|
|
|
757 dump_block_info (bb);
|
|
|
758 }
|
|
|
759
|
|
|
760 /* Return true if REGNO is worth rematerializing. */
|
|
|
761
|
|
|
762 bool
|
|
|
763 early_remat::interesting_regno_p (unsigned int regno)
|
|
|
764 {
|
|
|
765 /* Ignore unused registers. */
|
|
|
766 rtx reg = regno_reg_rtx[regno];
|
|
|
767 if (!reg || DF_REG_DEF_COUNT (regno) == 0)
|
|
|
768 return false;
|
|
|
769
|
|
|
770 /* Make sure the register has a mode that we want to rematerialize. */
|
|
|
771 if (!bitmap_bit_p (m_selected_modes, GET_MODE (reg)))
|
|
|
772 return false;
|
|
|
773
|
|
|
774 /* Ignore values that might sometimes be used uninitialized. We could
|
|
|
775 instead add dummy candidates for the entry block definition, and so
|
|
|
776 handle uses that are definitely not uninitialized, but the combination
|
|
|
777 of the two should be rare in practice. */
|
|
|
778 if (bitmap_bit_p (DF_LR_OUT (ENTRY_BLOCK_PTR_FOR_FN (m_fn)), regno))
|
|
|
779 return false;
|
|
|
780
|
|
|
781 return true;
|
|
|
782 }
|
|
|
783
|
|
|
784 /* Record the set of register REGNO in instruction INSN as a
|
|
|
785 rematerialization candidate. CAN_COPY_P is true unless we already
|
|
|
786 know that rematerialization is impossible (in which case the candidate
|
|
|
787 only exists for the reaching definition calculation).
|
|
|
788
|
|
|
789 The candidate's index is not fixed at this stage. */
|
|
|
790
|
|
|
791 remat_candidate *
|
|
|
792 early_remat::add_candidate (rtx_insn *insn, unsigned int regno,
|
|
|
793 bool can_copy_p)
|
|
|
794 {
|
|
|
795 remat_candidate cand;
|
|
|
796 memset (&cand, 0, sizeof (cand));
|
|
|
797 cand.regno = regno;
|
|
|
798 cand.insn = insn;
|
|
|
799 cand.remat_rtx = PATTERN (insn);
|
|
|
800 cand.can_copy_p = can_copy_p;
|
|
|
801 m_candidates.safe_push (cand);
|
|
|
802
|
|
|
803 bitmap_set_bit (&m_candidate_regnos, regno);
|
|
|
804
|
|
|
805 return &m_candidates.last ();
|
|
|
806 }
|
|
|
807
|
|
|
808 /* Return true if we can rematerialize the set of register REGNO in
|
|
|
809 instruction INSN, and add it as a candidate if so. When returning
|
|
|
810 false, print the reason to the dump file. */
|
|
|
811
|
|
|
812 bool
|
|
|
813 early_remat::maybe_add_candidate (rtx_insn *insn, unsigned int regno)
|
|
|
814 {
|
|
|
815 #define FAILURE_FORMAT ";; Can't rematerialize set of reg %d in %d[bb:%d]: "
|
|
|
816 #define FAILURE_ARGS regno, INSN_UID (insn), BLOCK_FOR_INSN (insn)->index
|
|
|
817
|
|
|
818 /* The definition must come from an ordinary instruction. */
|
|
|
819 basic_block bb = BLOCK_FOR_INSN (insn);
|
|
|
820 if (!NONJUMP_INSN_P (insn)
|
|
|
821 || (insn == BB_END (bb)
|
|
|
822 && has_abnormal_or_eh_outgoing_edge_p (bb)))
|
|
|
823 {
|
|
|
824 if (dump_file)
|
|
|
825 fprintf (dump_file, FAILURE_FORMAT "insn alters control flow\n",
|
|
|
826 FAILURE_ARGS);
|
|
|
827 return false;
|
|
|
828 }
|
|
|
829
|
|
|
830 /* Prefer to rematerialize constants directly -- it's much easier. */
|
|
|
831 machine_mode mode = GET_MODE (regno_reg_rtx[regno]);
|
|
|
832 if (rtx note = find_reg_equal_equiv_note (insn))
|
|
|
833 {
|
|
|
834 rtx val = XEXP (note, 0);
|
|
|
835 if (CONSTANT_P (val)
|
|
|
836 && targetm.legitimate_constant_p (mode, val))
|
|
|
837 {
|
|
|
838 remat_candidate *cand = add_candidate (insn, regno, true);
|
|
|
839 cand->constant_p = true;
|
|
|
840 cand->remat_rtx = val;
|
|
|
841 return true;
|
|
|
842 }
|
|
|
843 }
|
|
|
844
|
|
|
845 /* See whether the target has reasons to prevent a copy. */
|
|
|
846 if (targetm.cannot_copy_insn_p && targetm.cannot_copy_insn_p (insn))
|
|
|
847 {
|
|
|
848 if (dump_file)
|
|
|
849 fprintf (dump_file, FAILURE_FORMAT "target forbids copying\n",
|
|
|
850 FAILURE_ARGS);
|
|
|
851 return false;
|
|
|
852 }
|
|
|
853
|
|
|
854 /* We can't copy trapping instructions. */
|
|
|
855 rtx pat = PATTERN (insn);
|
|
|
856 if (may_trap_p (pat))
|
|
|
857 {
|
|
|
858 if (dump_file)
|
|
|
859 fprintf (dump_file, FAILURE_FORMAT "insn might trap\n", FAILURE_ARGS);
|
|
|
860 return false;
|
|
|
861 }
|
|
|
862
|
|
|
863 /* We can't copy instructions that read memory, unless we know that
|
|
|
864 the contents never change. */
|
|
|
865 subrtx_iterator::array_type array;
|
|
|
866 FOR_EACH_SUBRTX (iter, array, pat, ALL)
|
|
|
867 if (MEM_P (*iter) && !MEM_READONLY_P (*iter))
|
|
|
868 {
|
|
|
869 if (dump_file)
|
|
|
870 fprintf (dump_file, FAILURE_FORMAT "insn references non-constant"
|
|
|
871 " memory\n", FAILURE_ARGS);
|
|
|
872 return false;
|
|
|
873 }
|
|
|
874
|
|
|
875 /* Check each defined register. */
|
|
|
876 df_ref ref;
|
|
|
877 FOR_EACH_INSN_DEF (ref, insn)
|
|
|
878 {
|
|
|
879 unsigned int def_regno = DF_REF_REGNO (ref);
|
|
|
880 if (def_regno == regno)
|
|
|
881 {
|
|
|
882 /* Make sure the definition is write-only. (Partial definitions,
|
|
|
883 such as setting the low part and clobbering the high part,
|
|
|
884 are otherwise OK.) */
|
|
|
885 if (DF_REF_FLAGS_IS_SET (ref, DF_REF_READ_WRITE))
|
|
|
886 {
|
|
|
887 if (dump_file)
|
|
|
888 fprintf (dump_file, FAILURE_FORMAT "destination is"
|
|
|
889 " read-modify-write\n", FAILURE_ARGS);
|
|
|
890 return false;
|
|
|
891 }
|
|
|
892 }
|
|
|
893 else
|
|
|
894 {
|
|
|
895 /* The instruction can set additional registers, provided that
|
|
145
|
896 they're hard registers. This is useful for instructions
|
|
|
897 that alter the condition codes. */
|
|
131
|
898 if (!HARD_REGISTER_NUM_P (def_regno))
|
|
|
899 {
|
|
|
900 if (dump_file)
|
|
|
901 fprintf (dump_file, FAILURE_FORMAT "insn also sets"
|
|
|
902 " pseudo reg %d\n", FAILURE_ARGS, def_regno);
|
|
|
903 return false;
|
|
|
904 }
|
|
|
905 }
|
|
|
906 }
|
|
|
907
|
|
|
908 /* If the instruction uses fixed hard registers, check that those
|
|
|
909 registers have the same value throughout the function. If the
|
|
|
910 instruction uses non-fixed hard registers, check that we can
|
|
|
911 replace them with pseudos. */
|
|
|
912 FOR_EACH_INSN_USE (ref, insn)
|
|
|
913 {
|
|
|
914 unsigned int use_regno = DF_REF_REGNO (ref);
|
|
|
915 if (HARD_REGISTER_NUM_P (use_regno) && fixed_regs[use_regno])
|
|
|
916 {
|
|
|
917 if (rtx_unstable_p (DF_REF_REAL_REG (ref)))
|
|
|
918 {
|
|
|
919 if (dump_file)
|
|
|
920 fprintf (dump_file, FAILURE_FORMAT "insn uses fixed hard reg"
|
|
|
921 " %d\n", FAILURE_ARGS, use_regno);
|
|
|
922 return false;
|
|
|
923 }
|
|
|
924 }
|
|
|
925 else if (HARD_REGISTER_NUM_P (use_regno))
|
|
|
926 {
|
|
|
927 /* Allocate a dummy pseudo register and temporarily install it.
|
|
|
928 Make the register number depend on the mode, which should
|
|
|
929 provide enough sharing for match_dup while also weeding
|
|
|
930 out cases in which operands with different modes are
|
|
|
931 explicitly tied. */
|
|
|
932 rtx *loc = DF_REF_REAL_LOC (ref);
|
|
|
933 unsigned int size = RTX_CODE_SIZE (REG);
|
|
|
934 rtx new_reg = (rtx) alloca (size);
|
|
|
935 memset (new_reg, 0, size);
|
|
|
936 PUT_CODE (new_reg, REG);
|
|
|
937 set_mode_and_regno (new_reg, GET_MODE (*loc),
|
|
|
938 LAST_VIRTUAL_REGISTER + 1 + GET_MODE (*loc));
|
|
|
939 validate_change (insn, loc, new_reg, 1);
|
|
|
940 }
|
|
|
941 }
|
|
|
942 bool ok_p = verify_changes (0);
|
|
|
943 cancel_changes (0);
|
|
|
944 if (!ok_p)
|
|
|
945 {
|
|
|
946 if (dump_file)
|
|
|
947 fprintf (dump_file, FAILURE_FORMAT "insn does not allow hard"
|
|
|
948 " register inputs to be replaced\n", FAILURE_ARGS);
|
|
|
949 return false;
|
|
|
950 }
|
|
|
951
|
|
|
952 #undef FAILURE_ARGS
|
|
|
953 #undef FAILURE_FORMAT
|
|
|
954
|
|
|
955 add_candidate (insn, regno, true);
|
|
|
956 return true;
|
|
|
957 }
|
|
|
958
|
|
|
959 /* Calculate the set of rematerialization candidates. Return true if
|
|
|
960 we find at least one. */
|
|
|
961
|
|
|
962 bool
|
|
|
963 early_remat::collect_candidates (void)
|
|
|
964 {
|
|
|
965 unsigned int nregs = DF_REG_SIZE (df);
|
|
|
966 for (unsigned int regno = FIRST_PSEUDO_REGISTER; regno < nregs; ++regno)
|
|
|
967 if (interesting_regno_p (regno))
|
|
|
968 {
|
|
|
969 /* Create candidates for all suitable definitions. */
|
|
|
970 bitmap_clear (&m_tmp_bitmap);
|
|
|
971 unsigned int bad = 0;
|
|
|
972 unsigned int id = 0;
|
|
|
973 for (df_ref ref = DF_REG_DEF_CHAIN (regno); ref;
|
|
|
974 ref = DF_REF_NEXT_REG (ref))
|
|
|
975 {
|
|
|
976 rtx_insn *insn = DF_REF_INSN (ref);
|
|
|
977 if (maybe_add_candidate (insn, regno))
|
|
|
978 bitmap_set_bit (&m_tmp_bitmap, id);
|
|
|
979 else
|
|
|
980 bad += 1;
|
|
|
981 id += 1;
|
|
|
982 }
|
|
|
983
|
|
|
984 /* If we found at least one suitable definition, add dummy
|
|
|
985 candidates for the rest, so that we can see which definitions
|
|
|
986 are live where. */
|
|
|
987 if (!bitmap_empty_p (&m_tmp_bitmap) && bad)
|
|
|
988 {
|
|
|
989 id = 0;
|
|
|
990 for (df_ref ref = DF_REG_DEF_CHAIN (regno); ref;
|
|
|
991 ref = DF_REF_NEXT_REG (ref))
|
|
|
992 {
|
|
|
993 if (!bitmap_bit_p (&m_tmp_bitmap, id))
|
|
|
994 add_candidate (DF_REF_INSN (ref), regno, false);
|
|
|
995 id += 1;
|
|
|
996 }
|
|
|
997 }
|
|
|
998 }
|
|
|
999
|
|
|
1000
|
|
|
1001 return !m_candidates.is_empty ();
|
|
|
1002 }
|
|
|
1003
|
|
|
1004 /* Initialize the m_block_info array. */
|
|
|
1005
|
|
|
1006 void
|
|
|
1007 early_remat::init_block_info (void)
|
|
|
1008 {
|
|
|
1009 unsigned int n_blocks = last_basic_block_for_fn (m_fn);
|
|
|
1010 m_block_info.safe_grow_cleared (n_blocks);
|
|
|
1011 }
|
|
|
1012
|
|
|
1013 /* Maps basic block indices to their position in the post order. */
|
|
|
1014 static unsigned int *postorder_index;
|
|
|
1015
|
|
|
1016 /* Order remat_candidates X_IN and Y_IN according to the cfg postorder. */
|
|
|
1017
|
|
|
1018 static int
|
|
|
1019 compare_candidates (const void *x_in, const void *y_in)
|
|
|
1020 {
|
|
|
1021 const remat_candidate *x = (const remat_candidate *) x_in;
|
|
|
1022 const remat_candidate *y = (const remat_candidate *) y_in;
|
|
|
1023 basic_block x_bb = BLOCK_FOR_INSN (x->insn);
|
|
|
1024 basic_block y_bb = BLOCK_FOR_INSN (y->insn);
|
|
|
1025 if (x_bb != y_bb)
|
|
|
1026 /* Make X and Y follow block postorder. */
|
|
|
1027 return postorder_index[x_bb->index] - postorder_index[y_bb->index];
|
|
|
1028
|
|
|
1029 /* Make X and Y follow a backward traversal of the containing block. */
|
|
|
1030 return DF_INSN_LUID (y->insn) - DF_INSN_LUID (x->insn);
|
|
|
1031 }
|
|
|
1032
|
|
|
1033 /* Sort the collected rematerialization candidates so that they follow
|
|
|
1034 cfg postorder. */
|
|
|
1035
|
|
|
1036 void
|
|
|
1037 early_remat::sort_candidates (void)
|
|
|
1038 {
|
|
|
1039 /* Make sure the DF LUIDs are up-to-date for all the blocks we
|
|
|
1040 care about. */
|
|
|
1041 bitmap_clear (&m_tmp_bitmap);
|
|
|
1042 unsigned int cand_index;
|
|
|
1043 remat_candidate *cand;
|
|
|
1044 FOR_EACH_VEC_ELT (m_candidates, cand_index, cand)
|
|
|
1045 {
|
|
|
1046 basic_block bb = BLOCK_FOR_INSN (cand->insn);
|
|
|
1047 if (bitmap_set_bit (&m_tmp_bitmap, bb->index))
|
|
|
1048 df_recompute_luids (bb);
|
|
|
1049 }
|
|
|
1050
|
|
|
1051 /* Create a mapping from block numbers to their position in the
|
|
|
1052 postorder. */
|
|
|
1053 unsigned int n_blocks = last_basic_block_for_fn (m_fn);
|
|
|
1054 int *postorder = df_get_postorder (DF_BACKWARD);
|
|
|
1055 unsigned int postorder_len = df_get_n_blocks (DF_BACKWARD);
|
|
|
1056 postorder_index = new unsigned int[n_blocks];
|
|
|
1057 for (unsigned int i = 0; i < postorder_len; ++i)
|
|
|
1058 postorder_index[postorder[i]] = i;
|
|
|
1059
|
|
|
1060 m_candidates.qsort (compare_candidates);
|
|
|
1061
|
|
|
1062 delete postorder_index;
|
|
|
1063 }
|
|
|
1064
|
|
|
1065 /* Commit to the current candidate indices and initialize cross-references. */
|
|
|
1066
|
|
|
1067 void
|
|
|
1068 early_remat::finalize_candidate_indices (void)
|
|
|
1069 {
|
|
|
1070 /* Create a bitmap for each candidate register. */
|
|
|
1071 m_regno_to_candidates.safe_grow (max_reg_num ());
|
|
|
1072 unsigned int regno;
|
|
|
1073 bitmap_iterator bi;
|
|
|
1074 EXECUTE_IF_SET_IN_BITMAP (&m_candidate_regnos, 0, regno, bi)
|
|
|
1075 m_regno_to_candidates[regno] = alloc_bitmap ();
|
|
|
1076
|
|
|
1077 /* Go through each candidate and record its index. */
|
|
|
1078 unsigned int cand_index;
|
|
|
1079 remat_candidate *cand;
|
|
|
1080 FOR_EACH_VEC_ELT (m_candidates, cand_index, cand)
|
|
|
1081 {
|
|
|
1082 basic_block bb = BLOCK_FOR_INSN (cand->insn);
|
|
|
1083 remat_block_info *info = &m_block_info[bb->index];
|
|
|
1084 info->num_candidates += 1;
|
|
|
1085 info->first_candidate = cand_index;
|
|
|
1086 bitmap_set_bit (m_regno_to_candidates[cand->regno], cand_index);
|
|
|
1087 }
|
|
|
1088 }
|
|
|
1089
|
|
|
1090 /* Record that candidates CAND1_INDEX and CAND2_INDEX are equivalent.
|
|
|
1091 CAND1_INDEX might already have an equivalence class, but CAND2_INDEX
|
|
|
1092 doesn't. */
|
|
|
1093
|
|
|
1094 void
|
|
|
1095 early_remat::record_equiv_candidates (unsigned int cand1_index,
|
|
|
1096 unsigned int cand2_index)
|
|
|
1097 {
|
|
|
1098 if (dump_file)
|
|
|
1099 fprintf (dump_file, ";; Candidate %d is equivalent to candidate %d\n",
|
|
|
1100 cand2_index, cand1_index);
|
|
|
1101
|
|
|
1102 remat_candidate *cand1 = &m_candidates[cand1_index];
|
|
|
1103 remat_candidate *cand2 = &m_candidates[cand2_index];
|
|
|
1104 gcc_checking_assert (!cand2->equiv_class);
|
|
|
1105
|
|
|
1106 remat_equiv_class *ec = cand1->equiv_class;
|
|
|
1107 if (!ec)
|
|
|
1108 {
|
|
|
1109 ec = XOBNEW (&m_obstack.obstack, remat_equiv_class);
|
|
|
1110 ec->members = alloc_bitmap ();
|
|
|
1111 bitmap_set_bit (ec->members, cand1_index);
|
|
|
1112 ec->earliest = cand1_index;
|
|
|
1113 ec->representative = cand1_index;
|
|
|
1114 cand1->equiv_class = ec;
|
|
|
1115 }
|
|
|
1116 cand2->equiv_class = ec;
|
|
|
1117 bitmap_set_bit (ec->members, cand2_index);
|
|
|
1118 if (cand2_index > ec->representative)
|
|
|
1119 ec->representative = cand2_index;
|
|
|
1120 }
|
|
|
1121
|
|
|
1122 /* Propagate information from the rd_out set of E->src to the rd_in set
|
|
|
1123 of E->dest, when computing global reaching definitions. Return true
|
|
|
1124 if something changed. */
|
|
|
1125
|
|
|
1126 bool
|
|
|
1127 early_remat::rd_confluence_n (edge e)
|
|
|
1128 {
|
|
|
1129 remat_block_info *src = &er->m_block_info[e->src->index];
|
|
|
1130 remat_block_info *dest = &er->m_block_info[e->dest->index];
|
|
|
1131
|
|
|
1132 /* available_in temporarily contains the set of candidates whose
|
|
|
1133 registers are live on entry. */
|
|
|
1134 if (empty_p (src->rd_out) || empty_p (dest->available_in))
|
|
|
1135 return false;
|
|
|
1136
|
|
|
1137 return bitmap_ior_and_into (er->get_bitmap (&dest->rd_in),
|
|
|
1138 src->rd_out, dest->available_in);
|
|
|
1139 }
|
|
|
1140
|
|
|
1141 /* Propagate information from the rd_in set of block BB_INDEX to rd_out.
|
|
|
1142 Return true if something changed. */
|
|
|
1143
|
|
|
1144 bool
|
|
|
1145 early_remat::rd_transfer (int bb_index)
|
|
|
1146 {
|
|
|
1147 remat_block_info *info = &er->m_block_info[bb_index];
|
|
|
1148
|
|
|
1149 if (empty_p (info->rd_in))
|
|
|
1150 return false;
|
|
|
1151
|
|
|
1152 if (empty_p (info->rd_kill))
|
|
|
1153 {
|
|
|
1154 gcc_checking_assert (empty_p (info->rd_gen));
|
|
|
1155 if (!info->rd_out)
|
|
|
1156 info->rd_out = info->rd_in;
|
|
|
1157 else
|
|
|
1158 gcc_checking_assert (info->rd_out == info->rd_in);
|
|
|
1159 /* Assume that we only get called if something changed. */
|
|
|
1160 return true;
|
|
|
1161 }
|
|
|
1162
|
|
|
1163 if (empty_p (info->rd_gen))
|
|
|
1164 return bitmap_and_compl (er->get_bitmap (&info->rd_out),
|
|
|
1165 info->rd_in, info->rd_kill);
|
|
|
1166
|
|
|
1167 return bitmap_ior_and_compl (er->get_bitmap (&info->rd_out), info->rd_gen,
|
|
|
1168 info->rd_in, info->rd_kill);
|
|
|
1169 }
|
|
|
1170
|
|
|
1171 /* Calculate the rd_* sets for each block. */
|
|
|
1172
|
|
|
1173 void
|
|
|
1174 early_remat::compute_rd (void)
|
|
|
1175 {
|
|
|
1176 /* First calculate the rd_kill and rd_gen sets, using the fact
|
|
|
1177 that m_candidates is sorted in order of decreasing LUID. */
|
|
|
1178 unsigned int cand_index;
|
|
|
1179 remat_candidate *cand;
|
|
|
1180 FOR_EACH_VEC_ELT_REVERSE (m_candidates, cand_index, cand)
|
|
|
1181 {
|
|
|
1182 rtx_insn *insn = cand->insn;
|
|
|
1183 basic_block bb = BLOCK_FOR_INSN (insn);
|
|
|
1184 remat_block_info *info = &m_block_info[bb->index];
|
|
|
1185 bitmap kill = m_regno_to_candidates[cand->regno];
|
|
|
1186 bitmap_ior_into (get_bitmap (&info->rd_kill), kill);
|
|
|
1187 if (bitmap_bit_p (DF_LR_OUT (bb), cand->regno))
|
|
|
1188 {
|
|
|
1189 bitmap_and_compl_into (get_bitmap (&info->rd_gen), kill);
|
|
|
1190 bitmap_set_bit (info->rd_gen, cand_index);
|
|
|
1191 }
|
|
|
1192 }
|
|
|
1193
|
|
|
1194 /* Set up the initial values of the other sets. */
|
|
|
1195 basic_block bb;
|
|
|
1196 FOR_EACH_BB_FN (bb, m_fn)
|
|
|
1197 {
|
|
|
1198 remat_block_info *info = &m_block_info[bb->index];
|
|
|
1199 unsigned int regno;
|
|
|
1200 bitmap_iterator bi;
|
|
|
1201 EXECUTE_IF_AND_IN_BITMAP (DF_LR_IN (bb), &m_candidate_regnos,
|
|
|
1202 0, regno, bi)
|
|
|
1203 {
|
|
|
1204 /* Use available_in to record the set of candidates whose
|
|
|
1205 registers are live on entry (i.e. a maximum bound on rd_in). */
|
|
|
1206 bitmap_ior_into (get_bitmap (&info->available_in),
|
|
|
1207 m_regno_to_candidates[regno]);
|
|
|
1208
|
|
|
1209 /* Add registers that die in a block to the block's kill set,
|
|
|
1210 so that we don't needlessly propagate them through the rest
|
|
|
1211 of the function. */
|
|
|
1212 if (!bitmap_bit_p (DF_LR_OUT (bb), regno))
|
|
|
1213 bitmap_ior_into (get_bitmap (&info->rd_kill),
|
|
|
1214 m_regno_to_candidates[regno]);
|
|
|
1215 }
|
|
|
1216
|
|
|
1217 /* Initialize each block's rd_out to the minimal set (the set of
|
|
|
1218 local definitions). */
|
|
|
1219 if (!empty_p (info->rd_gen))
|
|
|
1220 bitmap_copy (get_bitmap (&info->rd_out), info->rd_gen);
|
|
|
1221 }
|
|
|
1222
|
|
|
1223 /* Iterate until we reach a fixed point. */
|
|
|
1224 er = this;
|
|
|
1225 bitmap_clear (&m_tmp_bitmap);
|
|
|
1226 bitmap_set_range (&m_tmp_bitmap, 0, last_basic_block_for_fn (m_fn));
|
|
|
1227 df_simple_dataflow (DF_FORWARD, NULL, NULL, rd_confluence_n, rd_transfer,
|
|
|
1228 &m_tmp_bitmap, df_get_postorder (DF_FORWARD),
|
|
|
1229 df_get_n_blocks (DF_FORWARD));
|
|
|
1230 er = 0;
|
|
|
1231
|
|
|
1232 /* Work out which definitions reach which candidates, again taking
|
|
|
1233 advantage of the candidate order. */
|
|
|
1234 bitmap_head reaching;
|
|
|
1235 bitmap_initialize (&reaching, &m_obstack);
|
|
|
1236 basic_block old_bb = NULL;
|
|
|
1237 FOR_EACH_VEC_ELT_REVERSE (m_candidates, cand_index, cand)
|
|
|
1238 {
|
|
|
1239 bb = BLOCK_FOR_INSN (cand->insn);
|
|
|
1240 if (bb != old_bb)
|
|
|
1241 {
|
|
|
1242 /* Get the definitions that reach the start of the new block. */
|
|
|
1243 remat_block_info *info = &m_block_info[bb->index];
|
|
|
1244 if (info->rd_in)
|
|
|
1245 bitmap_copy (&reaching, info->rd_in);
|
|
|
1246 else
|
|
|
1247 bitmap_clear (&reaching);
|
|
|
1248 old_bb = bb;
|
|
|
1249 }
|
|
|
1250 else
|
|
|
1251 {
|
|
|
1252 /* Process the definitions of the previous instruction. */
|
|
|
1253 bitmap kill = m_regno_to_candidates[cand[1].regno];
|
|
|
1254 bitmap_and_compl_into (&reaching, kill);
|
|
|
1255 bitmap_set_bit (&reaching, cand_index + 1);
|
|
|
1256 }
|
|
|
1257
|
|
|
1258 if (cand->can_copy_p && !cand->constant_p)
|
|
|
1259 {
|
|
|
1260 df_ref ref;
|
|
|
1261 FOR_EACH_INSN_USE (ref, cand->insn)
|
|
|
1262 {
|
|
|
1263 unsigned int regno = DF_REF_REGNO (ref);
|
|
|
1264 if (bitmap_bit_p (&m_candidate_regnos, regno))
|
|
|
1265 {
|
|
|
1266 bitmap defs = m_regno_to_candidates[regno];
|
|
|
1267 bitmap_and (&m_tmp_bitmap, defs, &reaching);
|
|
|
1268 bitmap_ior_into (get_bitmap (&cand->uses), &m_tmp_bitmap);
|
|
|
1269 }
|
|
|
1270 }
|
|
|
1271 }
|
|
|
1272 }
|
|
|
1273 bitmap_clear (&reaching);
|
|
|
1274 }
|
|
|
1275
|
|
|
1276 /* If CAND_INDEX is in an equivalence class, return the representative
|
|
|
1277 of the class, otherwise return CAND_INDEX. */
|
|
|
1278
|
|
|
1279 inline unsigned int
|
|
|
1280 early_remat::canon_candidate (unsigned int cand_index)
|
|
|
1281 {
|
|
|
1282 if (remat_equiv_class *ec = m_candidates[cand_index].equiv_class)
|
|
|
1283 return ec->representative;
|
|
|
1284 return cand_index;
|
|
|
1285 }
|
|
|
1286
|
|
|
1287 /* Make candidate set *PTR refer to candidates using the representative
|
|
|
1288 of each equivalence class. */
|
|
|
1289
|
|
|
1290 void
|
|
|
1291 early_remat::canon_bitmap (bitmap *ptr)
|
|
|
1292 {
|
|
|
1293 bitmap old_set = *ptr;
|
|
|
1294 if (empty_p (old_set))
|
|
|
1295 return;
|
|
|
1296
|
|
|
1297 bitmap new_set = NULL;
|
|
|
1298 unsigned int old_index;
|
|
|
1299 bitmap_iterator bi;
|
|
|
1300 EXECUTE_IF_SET_IN_BITMAP (old_set, 0, old_index, bi)
|
|
|
1301 {
|
|
|
1302 unsigned int new_index = canon_candidate (old_index);
|
|
|
1303 if (old_index != new_index)
|
|
|
1304 {
|
|
|
1305 if (!new_set)
|
|
|
1306 {
|
|
|
1307 new_set = alloc_bitmap ();
|
|
|
1308 bitmap_copy (new_set, old_set);
|
|
|
1309 }
|
|
|
1310 bitmap_clear_bit (new_set, old_index);
|
|
|
1311 bitmap_set_bit (new_set, new_index);
|
|
|
1312 }
|
|
|
1313 }
|
|
|
1314 if (new_set)
|
|
|
1315 {
|
|
|
1316 BITMAP_FREE (*ptr);
|
|
|
1317 *ptr = new_set;
|
|
|
1318 }
|
|
|
1319 }
|
|
|
1320
|
|
|
1321 /* If the candidates in REACHING all have the same value, return the
|
|
|
1322 earliest instance of that value (i.e. the first one to be added
|
|
|
1323 to m_value_table), otherwise return MULTIPLE_CANDIDATES. */
|
|
|
1324
|
|
|
1325 unsigned int
|
|
|
1326 early_remat::resolve_reaching_def (bitmap reaching)
|
|
|
1327 {
|
|
|
1328 unsigned int cand_index = bitmap_first_set_bit (reaching);
|
|
|
1329 if (remat_equiv_class *ec = m_candidates[cand_index].equiv_class)
|
|
|
1330 {
|
|
|
1331 if (!bitmap_intersect_compl_p (reaching, ec->members))
|
|
|
1332 return ec->earliest;
|
|
|
1333 }
|
|
|
1334 else if (bitmap_single_bit_set_p (reaching))
|
|
|
1335 return cand_index;
|
|
|
1336
|
|
|
1337 return MULTIPLE_CANDIDATES;
|
|
|
1338 }
|
|
|
1339
|
|
|
1340 /* Check whether all candidate registers used by candidate CAND_INDEX have
|
|
|
1341 unique definitions. Return true if so, replacing the candidate's uses
|
|
|
1342 set with the appropriate form for value numbering. */
|
|
|
1343
|
|
|
1344 bool
|
|
|
1345 early_remat::check_candidate_uses (unsigned int cand_index)
|
|
|
1346 {
|
|
|
1347 remat_candidate *cand = &m_candidates[cand_index];
|
|
|
1348
|
|
|
1349 /* Process the uses for each register in turn. */
|
|
|
1350 bitmap_head uses;
|
|
|
1351 bitmap_initialize (&uses, &m_obstack);
|
|
|
1352 bitmap_copy (&uses, cand->uses);
|
|
|
1353 bitmap uses_ec = alloc_bitmap ();
|
|
|
1354 while (!bitmap_empty_p (&uses))
|
|
|
1355 {
|
|
|
1356 /* Get the register for the lowest-indexed candidate remaining,
|
|
|
1357 and the reaching definitions of that register. */
|
|
|
1358 unsigned int first = bitmap_first_set_bit (&uses);
|
|
|
1359 unsigned int regno = m_candidates[first].regno;
|
|
|
1360 bitmap_and (&m_tmp_bitmap, &uses, m_regno_to_candidates[regno]);
|
|
|
1361
|
|
|
1362 /* See whether all reaching definitions have the same value and if
|
|
|
1363 so get the index of the first candidate we saw with that value. */
|
|
|
1364 unsigned int def = resolve_reaching_def (&m_tmp_bitmap);
|
|
|
1365 if (def == MULTIPLE_CANDIDATES)
|
|
|
1366 {
|
|
|
1367 if (dump_file)
|
|
|
1368 fprintf (dump_file, ";; Removing candidate %d because there is"
|
|
|
1369 " more than one reaching definition of reg %d\n",
|
|
|
1370 cand_index, regno);
|
|
|
1371 cand->can_copy_p = false;
|
|
|
1372 break;
|
|
|
1373 }
|
|
|
1374 bitmap_set_bit (uses_ec, def);
|
|
|
1375 bitmap_and_compl_into (&uses, &m_tmp_bitmap);
|
|
|
1376 }
|
|
|
1377 BITMAP_FREE (cand->uses);
|
|
|
1378 cand->uses = uses_ec;
|
|
|
1379 return cand->can_copy_p;
|
|
|
1380 }
|
|
|
1381
|
|
|
1382 /* Calculate the set of hard registers that would be clobbered by
|
|
|
1383 rematerializing candidate CAND_INDEX. At this point the candidate's
|
|
|
1384 set of uses is final. */
|
|
|
1385
|
|
|
1386 void
|
|
|
1387 early_remat::compute_clobbers (unsigned int cand_index)
|
|
|
1388 {
|
|
|
1389 remat_candidate *cand = &m_candidates[cand_index];
|
|
|
1390 if (cand->uses)
|
|
|
1391 {
|
|
|
1392 unsigned int use_index;
|
|
|
1393 bitmap_iterator bi;
|
|
|
1394 EXECUTE_IF_SET_IN_BITMAP (cand->uses, 0, use_index, bi)
|
|
|
1395 if (bitmap clobbers = m_candidates[use_index].clobbers)
|
|
|
1396 bitmap_ior_into (get_bitmap (&cand->clobbers), clobbers);
|
|
|
1397 }
|
|
|
1398
|
|
|
1399 df_ref ref;
|
|
|
1400 FOR_EACH_INSN_DEF (ref, cand->insn)
|
|
|
1401 {
|
|
|
1402 unsigned int def_regno = DF_REF_REGNO (ref);
|
|
|
1403 if (def_regno != cand->regno)
|
|
|
1404 bitmap_set_bit (get_bitmap (&cand->clobbers), def_regno);
|
|
|
1405 }
|
|
|
1406 }
|
|
|
1407
|
|
|
1408 /* Mark candidate CAND_INDEX as validated and add it to the value table. */
|
|
|
1409
|
|
|
1410 void
|
|
|
1411 early_remat::assign_value_number (unsigned int cand_index)
|
|
|
1412 {
|
|
|
1413 remat_candidate *cand = &m_candidates[cand_index];
|
|
|
1414 gcc_checking_assert (cand->can_copy_p && !cand->validated_p);
|
|
|
1415
|
|
|
1416 compute_clobbers (cand_index);
|
|
|
1417 cand->validated_p = true;
|
|
|
1418
|
|
|
1419 inchash::hash h;
|
|
|
1420 h.add_int (cand->regno);
|
|
|
1421 inchash::add_rtx (cand->remat_rtx, h);
|
|
|
1422 cand->hash = h.end ();
|
|
|
1423
|
|
|
1424 remat_candidate **slot
|
|
|
1425 = m_value_table.find_slot_with_hash (cand, cand->hash, INSERT);
|
|
|
1426 if (!*slot)
|
|
|
1427 {
|
|
|
1428 *slot = cand;
|
|
|
1429 if (dump_file)
|
|
|
1430 fprintf (dump_file, ";; Candidate %d is not equivalent to"
|
|
|
1431 " others seen so far\n", cand_index);
|
|
|
1432 }
|
|
|
1433 else
|
|
|
1434 record_equiv_candidates (*slot - m_candidates.address (), cand_index);
|
|
|
1435 }
|
|
|
1436
|
|
|
1437 /* Make a final decision about which candidates are valid and assign
|
|
|
1438 value numbers to those that are. */
|
|
|
1439
|
|
|
1440 void
|
|
|
1441 early_remat::decide_candidate_validity (void)
|
|
|
1442 {
|
|
|
1443 auto_vec<unsigned int, 16> stack;
|
|
|
1444 unsigned int cand1_index;
|
|
|
1445 remat_candidate *cand1;
|
|
|
1446 FOR_EACH_VEC_ELT_REVERSE (m_candidates, cand1_index, cand1)
|
|
|
1447 {
|
|
|
1448 if (!cand1->can_copy_p || cand1->validated_p)
|
|
|
1449 continue;
|
|
|
1450
|
|
|
1451 if (empty_p (cand1->uses))
|
|
|
1452 {
|
|
|
1453 assign_value_number (cand1_index);
|
|
|
1454 continue;
|
|
|
1455 }
|
|
|
1456
|
|
|
1457 stack.safe_push (cand1_index);
|
|
|
1458 while (!stack.is_empty ())
|
|
|
1459 {
|
|
|
1460 unsigned int cand2_index = stack.last ();
|
|
|
1461 unsigned int watermark = stack.length ();
|
|
|
1462 remat_candidate *cand2 = &m_candidates[cand2_index];
|
|
|
1463 if (!cand2->can_copy_p || cand2->validated_p)
|
|
|
1464 {
|
|
|
1465 stack.pop ();
|
|
|
1466 continue;
|
|
|
1467 }
|
|
|
1468 cand2->visited_p = true;
|
|
|
1469 unsigned int cand3_index;
|
|
|
1470 bitmap_iterator bi;
|
|
|
1471 EXECUTE_IF_SET_IN_BITMAP (cand2->uses, 0, cand3_index, bi)
|
|
|
1472 {
|
|
|
1473 remat_candidate *cand3 = &m_candidates[cand3_index];
|
|
|
1474 if (!cand3->can_copy_p)
|
|
|
1475 {
|
|
|
1476 if (dump_file)
|
|
|
1477 fprintf (dump_file, ";; Removing candidate %d because"
|
|
|
1478 " it uses removed candidate %d\n", cand2_index,
|
|
|
1479 cand3_index);
|
|
|
1480 cand2->can_copy_p = false;
|
|
|
1481 break;
|
|
|
1482 }
|
|
|
1483 if (!cand3->validated_p)
|
|
|
1484 {
|
|
|
1485 if (empty_p (cand3->uses))
|
|
|
1486 assign_value_number (cand3_index);
|
|
|
1487 else if (cand3->visited_p)
|
|
|
1488 {
|
|
|
1489 if (dump_file)
|
|
|
1490 fprintf (dump_file, ";; Removing candidate %d"
|
|
|
1491 " because its definition is cyclic\n",
|
|
|
1492 cand2_index);
|
|
|
1493 cand2->can_copy_p = false;
|
|
|
1494 break;
|
|
|
1495 }
|
|
|
1496 else
|
|
|
1497 stack.safe_push (cand3_index);
|
|
|
1498 }
|
|
|
1499 }
|
|
|
1500 if (!cand2->can_copy_p)
|
|
|
1501 {
|
|
|
1502 cand2->visited_p = false;
|
|
|
1503 stack.truncate (watermark - 1);
|
|
|
1504 }
|
|
|
1505 else if (watermark == stack.length ())
|
|
|
1506 {
|
|
|
1507 cand2->visited_p = false;
|
|
|
1508 if (check_candidate_uses (cand2_index))
|
|
|
1509 assign_value_number (cand2_index);
|
|
|
1510 stack.pop ();
|
|
|
1511 }
|
|
|
1512 }
|
|
|
1513 }
|
|
|
1514
|
|
|
1515 /* Ensure that the candidates always use the same candidate index
|
|
|
1516 to refer to an equivalence class. */
|
|
|
1517 FOR_EACH_VEC_ELT_REVERSE (m_candidates, cand1_index, cand1)
|
|
|
1518 if (cand1->can_copy_p && !empty_p (cand1->uses))
|
|
|
1519 {
|
|
|
1520 canon_bitmap (&cand1->uses);
|
|
|
1521 gcc_checking_assert (bitmap_first_set_bit (cand1->uses) > cand1_index);
|
|
|
1522 }
|
|
|
1523 }
|
|
|
1524
|
|
145
|
1525 /* Remove any candidates in CANDIDATES that would clobber a register in
|
|
|
1526 UNAVAIL_REGS. */
|
|
|
1527
|
|
|
1528 void
|
|
|
1529 early_remat::restrict_remat_for_unavail_regs (bitmap candidates,
|
|
|
1530 const_bitmap unavail_regs)
|
|
|
1531 {
|
|
|
1532 bitmap_clear (&m_tmp_bitmap);
|
|
|
1533 unsigned int cand_index;
|
|
|
1534 bitmap_iterator bi;
|
|
|
1535 EXECUTE_IF_SET_IN_BITMAP (candidates, 0, cand_index, bi)
|
|
|
1536 {
|
|
|
1537 remat_candidate *cand = &m_candidates[cand_index];
|
|
|
1538 if (cand->clobbers
|
|
|
1539 && bitmap_intersect_p (cand->clobbers, unavail_regs))
|
|
|
1540 bitmap_set_bit (&m_tmp_bitmap, cand_index);
|
|
|
1541 }
|
|
|
1542 bitmap_and_compl_into (candidates, &m_tmp_bitmap);
|
|
|
1543 }
|
|
|
1544
|
|
|
1545 /* Remove any candidates in CANDIDATES that would clobber a register
|
|
|
1546 that is potentially live across CALL. */
|
|
|
1547
|
|
|
1548 void
|
|
|
1549 early_remat::restrict_remat_for_call (bitmap candidates, rtx_insn *call)
|
|
|
1550 {
|
|
|
1551 /* We don't know whether partially-clobbered registers are live
|
|
|
1552 across the call or not, so assume that they are. */
|
|
|
1553 bitmap_view<HARD_REG_SET> call_preserved_regs
|
|
|
1554 (~insn_callee_abi (call).full_reg_clobbers ());
|
|
|
1555 restrict_remat_for_unavail_regs (candidates, call_preserved_regs);
|
|
|
1556 }
|
|
|
1557
|
|
131
|
1558 /* Assuming that every path reaching a point P contains a copy of a
|
|
|
1559 use U of REGNO, return true if another copy of U at P would have
|
|
|
1560 access to the same value of REGNO. */
|
|
|
1561
|
|
|
1562 bool
|
|
|
1563 early_remat::stable_use_p (unsigned int regno)
|
|
|
1564 {
|
|
|
1565 /* Conservatively assume not for hard registers. */
|
|
|
1566 if (HARD_REGISTER_NUM_P (regno))
|
|
|
1567 return false;
|
|
|
1568
|
|
|
1569 /* See if REGNO has a single definition and is never used uninitialized.
|
|
|
1570 In this case the definition of REGNO dominates the common dominator
|
|
|
1571 of the uses U, which in turn dominates P. */
|
|
|
1572 if (DF_REG_DEF_COUNT (regno) == 1
|
|
|
1573 && !bitmap_bit_p (DF_LR_OUT (ENTRY_BLOCK_PTR_FOR_FN (m_fn)), regno))
|
|
|
1574 return true;
|
|
|
1575
|
|
|
1576 return false;
|
|
|
1577 }
|
|
|
1578
|
|
|
1579 /* Emit a copy from register DEST to register SRC before candidate
|
|
|
1580 CAND_INDEX's instruction. */
|
|
|
1581
|
|
|
1582 void
|
|
|
1583 early_remat::emit_copy_before (unsigned int cand_index, rtx dest, rtx src)
|
|
|
1584 {
|
|
|
1585 remat_candidate *cand = &m_candidates[cand_index];
|
|
|
1586 if (dump_file)
|
|
|
1587 {
|
|
|
1588 fprintf (dump_file, ";; Stabilizing insn ");
|
|
|
1589 dump_insn_id (cand->insn);
|
|
|
1590 fprintf (dump_file, " by copying source reg %d:%s to temporary reg %d\n",
|
|
|
1591 REGNO (src), GET_MODE_NAME (GET_MODE (src)), REGNO (dest));
|
|
|
1592 }
|
|
|
1593 emit_insn_before (gen_move_insn (dest, src), cand->insn);
|
|
|
1594 }
|
|
|
1595
|
|
|
1596 /* Check whether any inputs to candidate CAND_INDEX's instruction could
|
|
|
1597 change at rematerialization points and replace them with new pseudo
|
|
|
1598 registers if so. */
|
|
|
1599
|
|
|
1600 void
|
|
|
1601 early_remat::stabilize_pattern (unsigned int cand_index)
|
|
|
1602 {
|
|
|
1603 remat_candidate *cand = &m_candidates[cand_index];
|
|
|
1604 if (cand->stabilized_p)
|
|
|
1605 return;
|
|
|
1606
|
|
|
1607 remat_equiv_class *ec = cand->equiv_class;
|
|
|
1608 gcc_checking_assert (!ec || cand_index == ec->representative);
|
|
|
1609
|
|
|
1610 /* Record the replacements we've made so far, so that we don't
|
|
|
1611 create two separate registers for match_dups. Lookup is O(n),
|
|
|
1612 but the n is very small. */
|
|
|
1613 typedef std::pair<rtx, rtx> reg_pair;
|
|
|
1614 auto_vec<reg_pair, 16> reg_map;
|
|
|
1615
|
|
|
1616 rtx_insn *insn = cand->insn;
|
|
|
1617 df_ref ref;
|
|
|
1618 FOR_EACH_INSN_USE (ref, insn)
|
|
|
1619 {
|
|
|
1620 unsigned int old_regno = DF_REF_REGNO (ref);
|
|
|
1621 rtx *loc = DF_REF_REAL_LOC (ref);
|
|
|
1622
|
|
|
1623 if (HARD_REGISTER_NUM_P (old_regno) && fixed_regs[old_regno])
|
|
|
1624 {
|
|
|
1625 /* We checked when adding the candidate that the value is stable. */
|
|
|
1626 gcc_checking_assert (!rtx_unstable_p (*loc));
|
|
|
1627 continue;
|
|
|
1628 }
|
|
|
1629
|
|
|
1630 if (bitmap_bit_p (&m_candidate_regnos, old_regno))
|
|
|
1631 /* We already know which candidate provides the definition
|
|
|
1632 and will handle it during copying. */
|
|
|
1633 continue;
|
|
|
1634
|
|
|
1635 if (stable_use_p (old_regno))
|
|
|
1636 /* We can continue to use the existing register. */
|
|
|
1637 continue;
|
|
|
1638
|
|
|
1639 /* We need to replace the register. See whether we've already
|
|
|
1640 created a suitable copy. */
|
|
|
1641 rtx old_reg = *loc;
|
|
|
1642 rtx new_reg = NULL_RTX;
|
|
|
1643 machine_mode mode = GET_MODE (old_reg);
|
|
|
1644 reg_pair *p;
|
|
|
1645 unsigned int pi;
|
|
|
1646 FOR_EACH_VEC_ELT (reg_map, pi, p)
|
|
|
1647 if (REGNO (p->first) == old_regno
|
|
|
1648 && GET_MODE (p->first) == mode)
|
|
|
1649 {
|
|
|
1650 new_reg = p->second;
|
|
|
1651 break;
|
|
|
1652 }
|
|
|
1653
|
|
|
1654 if (!new_reg)
|
|
|
1655 {
|
|
|
1656 /* Create a new register and initialize it just before
|
|
|
1657 the instruction. */
|
|
|
1658 new_reg = gen_reg_rtx (mode);
|
|
|
1659 reg_map.safe_push (reg_pair (old_reg, new_reg));
|
|
|
1660 if (ec)
|
|
|
1661 {
|
|
|
1662 unsigned int member_index;
|
|
|
1663 bitmap_iterator bi;
|
|
|
1664 EXECUTE_IF_SET_IN_BITMAP (ec->members, 0, member_index, bi)
|
|
|
1665 emit_copy_before (member_index, new_reg, old_reg);
|
|
|
1666 }
|
|
|
1667 else
|
|
|
1668 emit_copy_before (cand_index, new_reg, old_reg);
|
|
|
1669 }
|
|
|
1670 validate_change (insn, loc, new_reg, true);
|
|
|
1671 }
|
|
|
1672 if (num_changes_pending ())
|
|
|
1673 {
|
|
|
1674 if (!apply_change_group ())
|
|
|
1675 /* We checked when adding the candidates that the pattern allows
|
|
|
1676 hard registers to be replaced. Nothing else should make the
|
|
|
1677 changes invalid. */
|
|
|
1678 gcc_unreachable ();
|
|
|
1679
|
|
|
1680 if (ec)
|
|
|
1681 {
|
|
|
1682 /* Copy the new pattern to other members of the equivalence
|
|
|
1683 class. */
|
|
|
1684 unsigned int member_index;
|
|
|
1685 bitmap_iterator bi;
|
|
|
1686 EXECUTE_IF_SET_IN_BITMAP (ec->members, 0, member_index, bi)
|
|
|
1687 if (cand_index != member_index)
|
|
|
1688 {
|
|
|
1689 rtx_insn *other_insn = m_candidates[member_index].insn;
|
|
|
1690 if (!validate_change (other_insn, &PATTERN (other_insn),
|
|
|
1691 copy_insn (PATTERN (insn)), 0))
|
|
|
1692 /* If the original instruction was valid then the copy
|
|
|
1693 should be too. */
|
|
|
1694 gcc_unreachable ();
|
|
|
1695 }
|
|
|
1696 }
|
|
|
1697 }
|
|
|
1698
|
|
|
1699 cand->stabilized_p = true;
|
|
|
1700 }
|
|
|
1701
|
|
|
1702 /* Change CAND's instruction so that it sets CAND->copy_regno instead
|
|
|
1703 of CAND->regno. */
|
|
|
1704
|
|
|
1705 void
|
|
|
1706 early_remat::replace_dest_with_copy (unsigned int cand_index)
|
|
|
1707 {
|
|
|
1708 remat_candidate *cand = &m_candidates[cand_index];
|
|
|
1709 df_ref def;
|
|
|
1710 FOR_EACH_INSN_DEF (def, cand->insn)
|
|
|
1711 if (DF_REF_REGNO (def) == cand->regno)
|
|
|
1712 validate_change (cand->insn, DF_REF_REAL_LOC (def),
|
|
|
1713 regno_reg_rtx[cand->copy_regno], 1);
|
|
|
1714 }
|
|
|
1715
|
|
|
1716 /* Make sure that the candidates used by candidate CAND_INDEX are available.
|
|
|
1717 There are two ways of doing this for an input candidate I:
|
|
|
1718
|
|
|
1719 (1) Using the existing register number and ensuring that I is available.
|
|
|
1720
|
|
|
1721 (2) Using a new register number (recorded in copy_regno) and adding I
|
|
|
1722 to VIA_COPY. This guarantees that making I available does not
|
|
|
1723 conflict with other uses of the original register.
|
|
|
1724
|
|
|
1725 REQUIRED is the set of candidates that are required but not available
|
|
|
1726 before the copy of CAND_INDEX. AVAILABLE is the set of candidates
|
|
|
1727 that are already available before the copy of CAND_INDEX. REACHING
|
|
|
1728 is the set of candidates that reach the copy of CAND_INDEX. VIA_COPY
|
|
|
1729 is the set of candidates that will use new register numbers recorded
|
|
|
1730 in copy_regno instead of the original ones. */
|
|
|
1731
|
|
|
1732 void
|
|
|
1733 early_remat::stabilize_candidate_uses (unsigned int cand_index,
|
|
|
1734 bitmap required, bitmap available,
|
|
|
1735 bitmap reaching, bitmap via_copy)
|
|
|
1736 {
|
|
|
1737 remat_candidate *cand = &m_candidates[cand_index];
|
|
|
1738 df_ref use;
|
|
|
1739 FOR_EACH_INSN_USE (use, cand->insn)
|
|
|
1740 {
|
|
|
1741 unsigned int regno = DF_REF_REGNO (use);
|
|
|
1742 if (!bitmap_bit_p (&m_candidate_regnos, regno))
|
|
|
1743 continue;
|
|
|
1744
|
|
|
1745 /* Work out which candidate provides the definition. */
|
|
|
1746 bitmap defs = m_regno_to_candidates[regno];
|
|
|
1747 bitmap_and (&m_tmp_bitmap, cand->uses, defs);
|
|
|
1748 gcc_checking_assert (bitmap_single_bit_set_p (&m_tmp_bitmap));
|
|
|
1749 unsigned int def_index = bitmap_first_set_bit (&m_tmp_bitmap);
|
|
|
1750
|
|
|
1751 /* First see if DEF_INDEX is the only reaching definition of REGNO
|
|
|
1752 at this point too and if it is or will become available. We can
|
|
|
1753 continue to use REGNO if so. */
|
|
|
1754 bitmap_and (&m_tmp_bitmap, reaching, defs);
|
|
|
1755 if (bitmap_single_bit_set_p (&m_tmp_bitmap)
|
|
|
1756 && bitmap_first_set_bit (&m_tmp_bitmap) == def_index
|
|
|
1757 && ((available && bitmap_bit_p (available, def_index))
|
|
|
1758 || bitmap_bit_p (required, def_index)))
|
|
|
1759 {
|
|
|
1760 if (dump_file)
|
|
|
1761 fprintf (dump_file, ";; Keeping reg %d for use of candidate %d"
|
|
|
1762 " in candidate %d\n", regno, def_index, cand_index);
|
|
|
1763 continue;
|
|
|
1764 }
|
|
|
1765
|
|
|
1766 /* Otherwise fall back to using a copy. There are other cases
|
|
|
1767 in which we *could* continue to use REGNO, but there's not
|
|
|
1768 really much point. Using a separate register ought to make
|
|
|
1769 things easier for the register allocator. */
|
|
|
1770 remat_candidate *def_cand = &m_candidates[def_index];
|
|
|
1771 rtx *loc = DF_REF_REAL_LOC (use);
|
|
|
1772 rtx new_reg;
|
|
|
1773 if (bitmap_set_bit (via_copy, def_index))
|
|
|
1774 {
|
|
|
1775 new_reg = gen_reg_rtx (GET_MODE (*loc));
|
|
|
1776 def_cand->copy_regno = REGNO (new_reg);
|
|
|
1777 if (dump_file)
|
|
|
1778 fprintf (dump_file, ";; Creating reg %d for use of candidate %d"
|
|
|
1779 " in candidate %d\n", REGNO (new_reg), def_index,
|
|
|
1780 cand_index);
|
|
|
1781 }
|
|
|
1782 else
|
|
|
1783 new_reg = regno_reg_rtx[def_cand->copy_regno];
|
|
|
1784 validate_change (cand->insn, loc, new_reg, 1);
|
|
|
1785 }
|
|
|
1786 }
|
|
|
1787
|
|
|
1788 /* Rematerialize the candidates in REQUIRED after instruction INSN,
|
|
|
1789 given that the candidates in AVAILABLE are already available
|
|
|
1790 and that REACHING is the set of candidates live after INSN.
|
|
|
1791 REQUIRED and AVAILABLE are disjoint on entry.
|
|
|
1792
|
|
|
1793 Clear REQUIRED on exit. */
|
|
|
1794
|
|
|
1795 void
|
|
|
1796 early_remat::emit_remat_insns (bitmap required, bitmap available,
|
|
|
1797 bitmap reaching, rtx_insn *insn)
|
|
|
1798 {
|
|
|
1799 /* Quick exit if there's nothing to do. */
|
|
|
1800 if (empty_p (required))
|
|
|
1801 return;
|
|
|
1802
|
|
|
1803 /* Only reaching definitions should be available or required. */
|
|
|
1804 gcc_checking_assert (!bitmap_intersect_compl_p (required, reaching));
|
|
|
1805 if (available)
|
|
|
1806 gcc_checking_assert (!bitmap_intersect_compl_p (available, reaching));
|
|
|
1807
|
|
|
1808 bitmap_head via_copy;
|
|
|
1809 bitmap_initialize (&via_copy, &m_obstack);
|
|
|
1810 while (!bitmap_empty_p (required) || !bitmap_empty_p (&via_copy))
|
|
|
1811 {
|
|
|
1812 /* Pick the lowest-indexed candidate left. */
|
|
|
1813 unsigned int required_index = (bitmap_empty_p (required)
|
|
|
1814 ? ~0U : bitmap_first_set_bit (required));
|
|
|
1815 unsigned int via_copy_index = (bitmap_empty_p (&via_copy)
|
|
|
1816 ? ~0U : bitmap_first_set_bit (&via_copy));
|
|
|
1817 unsigned int cand_index = MIN (required_index, via_copy_index);
|
|
|
1818 remat_candidate *cand = &m_candidates[cand_index];
|
|
|
1819
|
|
|
1820 bool via_copy_p = (cand_index == via_copy_index);
|
|
|
1821 if (via_copy_p)
|
|
|
1822 bitmap_clear_bit (&via_copy, cand_index);
|
|
|
1823 else
|
|
|
1824 {
|
|
|
1825 /* Remove all candidates for the same register from REQUIRED. */
|
|
|
1826 bitmap_and (&m_tmp_bitmap, reaching,
|
|
|
1827 m_regno_to_candidates[cand->regno]);
|
|
|
1828 bitmap_and_compl_into (required, &m_tmp_bitmap);
|
|
|
1829 gcc_checking_assert (!bitmap_bit_p (required, cand_index));
|
|
|
1830
|
|
|
1831 /* Only rematerialize if we have a single reaching definition
|
|
|
1832 of the register. */
|
|
|
1833 if (!bitmap_single_bit_set_p (&m_tmp_bitmap))
|
|
|
1834 {
|
|
|
1835 if (dump_file)
|
|
|
1836 {
|
|
|
1837 fprintf (dump_file, ";; Can't rematerialize reg %d after ",
|
|
|
1838 cand->regno);
|
|
|
1839 dump_insn_id (insn);
|
|
|
1840 fprintf (dump_file, ": more than one reaching definition\n");
|
|
|
1841 }
|
|
|
1842 continue;
|
|
|
1843 }
|
|
|
1844
|
|
|
1845 /* Skip candidates that can't be rematerialized. */
|
|
|
1846 if (!cand->can_copy_p)
|
|
|
1847 continue;
|
|
|
1848
|
|
|
1849 /* Check the function precondition. */
|
|
|
1850 gcc_checking_assert (!available
|
|
|
1851 || !bitmap_bit_p (available, cand_index));
|
|
|
1852 }
|
|
|
1853
|
|
|
1854 /* Invalid candidates should have been weeded out by now. */
|
|
|
1855 gcc_assert (cand->can_copy_p);
|
|
|
1856
|
|
|
1857 rtx new_pattern;
|
|
|
1858 if (cand->constant_p)
|
|
|
1859 {
|
|
|
1860 /* Emit a simple move. */
|
|
|
1861 unsigned int regno = via_copy_p ? cand->copy_regno : cand->regno;
|
|
|
1862 new_pattern = gen_move_insn (regno_reg_rtx[regno], cand->remat_rtx);
|
|
|
1863 }
|
|
|
1864 else
|
|
|
1865 {
|
|
|
1866 /* If this is the first time we've copied the instruction, make
|
|
|
1867 sure that any inputs will have the same value after INSN. */
|
|
|
1868 stabilize_pattern (cand_index);
|
|
|
1869
|
|
|
1870 /* Temporarily adjust the original instruction so that it has
|
|
|
1871 the right form for the copy. */
|
|
|
1872 if (via_copy_p)
|
|
|
1873 replace_dest_with_copy (cand_index);
|
|
|
1874 if (cand->uses)
|
|
|
1875 stabilize_candidate_uses (cand_index, required, available,
|
|
|
1876 reaching, &via_copy);
|
|
|
1877
|
|
|
1878 /* Get the new instruction pattern. */
|
|
|
1879 new_pattern = copy_insn (cand->remat_rtx);
|
|
|
1880
|
|
|
1881 /* Undo the temporary changes. */
|
|
|
1882 cancel_changes (0);
|
|
|
1883 }
|
|
|
1884
|
|
|
1885 /* Emit the new instruction. */
|
|
|
1886 rtx_insn *new_insn = emit_insn_after (new_pattern, insn);
|
|
|
1887
|
|
|
1888 if (dump_file)
|
|
|
1889 {
|
|
|
1890 fprintf (dump_file, ";; Rematerializing candidate %d after ",
|
|
|
1891 cand_index);
|
|
|
1892 dump_insn_id (insn);
|
|
|
1893 if (via_copy_p)
|
|
|
1894 fprintf (dump_file, " with new destination reg %d",
|
|
|
1895 cand->copy_regno);
|
|
|
1896 fprintf (dump_file, ":\n\n");
|
|
|
1897 print_rtl_single (dump_file, new_insn);
|
|
|
1898 fprintf (dump_file, "\n");
|
|
|
1899 }
|
|
|
1900 }
|
|
|
1901 }
|
|
|
1902
|
|
|
1903 /* Recompute INFO's available_out set, given that it's distinct from
|
|
|
1904 available_in and available_locally. */
|
|
|
1905
|
|
|
1906 bool
|
|
|
1907 early_remat::set_available_out (remat_block_info *info)
|
|
|
1908 {
|
|
|
1909 if (empty_p (info->available_locally))
|
|
|
1910 return bitmap_and_compl (get_bitmap (&info->available_out),
|
|
|
1911 info->available_in, info->rd_kill);
|
|
|
1912
|
|
|
1913 if (empty_p (info->rd_kill))
|
|
|
1914 return bitmap_ior (get_bitmap (&info->available_out),
|
|
|
1915 info->available_locally, info->available_in);
|
|
|
1916
|
|
|
1917 return bitmap_ior_and_compl (get_bitmap (&info->available_out),
|
|
|
1918 info->available_locally, info->available_in,
|
|
|
1919 info->rd_kill);
|
|
|
1920 }
|
|
|
1921
|
|
|
1922 /* If BB has more than one call, decide which candidates should be
|
|
|
1923 rematerialized after the non-final calls and emit the associated
|
|
|
1924 instructions. Record other information about the block in preparation
|
|
|
1925 for the global phase. */
|
|
|
1926
|
|
|
1927 void
|
|
|
1928 early_remat::process_block (basic_block bb)
|
|
|
1929 {
|
|
|
1930 remat_block_info *info = &m_block_info[bb->index];
|
|
|
1931 rtx_insn *last_call = NULL;
|
|
|
1932 rtx_insn *insn;
|
|
|
1933
|
|
|
1934 /* Ensure that we always use the same candidate index to refer to an
|
|
|
1935 equivalence class. */
|
|
|
1936 if (info->rd_out == info->rd_in)
|
|
|
1937 {
|
|
|
1938 canon_bitmap (&info->rd_in);
|
|
|
1939 info->rd_out = info->rd_in;
|
|
|
1940 }
|
|
|
1941 else
|
|
|
1942 {
|
|
|
1943 canon_bitmap (&info->rd_in);
|
|
|
1944 canon_bitmap (&info->rd_out);
|
|
|
1945 }
|
|
|
1946 canon_bitmap (&info->rd_kill);
|
|
|
1947 canon_bitmap (&info->rd_gen);
|
|
|
1948
|
|
|
1949 /* The set of candidates that should be rematerialized on entry to the
|
|
|
1950 block or after the previous call (whichever is more recent). */
|
|
|
1951 init_temp_bitmap (&m_required);
|
|
|
1952
|
|
|
1953 /* The set of candidates that reach the current instruction (i.e. are
|
|
|
1954 live just before the instruction). */
|
|
|
1955 bitmap_head reaching;
|
|
|
1956 bitmap_initialize (&reaching, &m_obstack);
|
|
|
1957 if (info->rd_in)
|
|
|
1958 bitmap_copy (&reaching, info->rd_in);
|
|
|
1959
|
|
|
1960 /* The set of candidates that are live and available without
|
|
|
1961 rematerialization just before the current instruction. This only
|
|
|
1962 accounts for earlier candidates in the block, or those that become
|
|
|
1963 available by being added to M_REQUIRED. */
|
|
|
1964 init_temp_bitmap (&m_available);
|
|
|
1965
|
|
|
1966 /* Get the range of candidates in the block. */
|
|
|
1967 unsigned int next_candidate = info->first_candidate;
|
|
|
1968 unsigned int num_candidates = info->num_candidates;
|
|
|
1969 remat_candidate *next_def = (num_candidates > 0
|
|
|
1970 ? &m_candidates[next_candidate]
|
|
|
1971 : NULL);
|
|
|
1972
|
|
|
1973 FOR_BB_INSNS (bb, insn)
|
|
|
1974 {
|
|
|
1975 if (!NONDEBUG_INSN_P (insn))
|
|
|
1976 continue;
|
|
|
1977
|
|
|
1978 /* First process uses, since this is a forward walk. */
|
|
|
1979 df_ref ref;
|
|
|
1980 FOR_EACH_INSN_USE (ref, insn)
|
|
|
1981 {
|
|
|
1982 unsigned int regno = DF_REF_REGNO (ref);
|
|
|
1983 if (bitmap_bit_p (&m_candidate_regnos, regno))
|
|
|
1984 {
|
|
|
1985 bitmap defs = m_regno_to_candidates[regno];
|
|
|
1986 bitmap_and (&m_tmp_bitmap, defs, &reaching);
|
|
|
1987 gcc_checking_assert (!bitmap_empty_p (&m_tmp_bitmap));
|
|
|
1988 if (!bitmap_intersect_p (defs, m_available))
|
|
|
1989 {
|
|
|
1990 /* There has been no definition of the register since
|
|
|
1991 the last call or the start of the block (whichever
|
|
|
1992 is most recent). Mark the reaching definitions
|
|
|
1993 as required at that point and thus available here. */
|
|
|
1994 bitmap_ior_into (m_required, &m_tmp_bitmap);
|
|
|
1995 bitmap_ior_into (m_available, &m_tmp_bitmap);
|
|
|
1996 }
|
|
|
1997 }
|
|
|
1998 }
|
|
|
1999
|
|
|
2000 if (CALL_P (insn))
|
|
|
2001 {
|
|
|
2002 if (!last_call)
|
|
|
2003 {
|
|
|
2004 /* The first call in the block. Record which candidates are
|
|
|
2005 required at the start of the block. */
|
|
|
2006 copy_temp_bitmap (&info->required_in, &m_required);
|
|
|
2007 init_temp_bitmap (&m_required);
|
|
|
2008 }
|
|
|
2009 else
|
|
145
|
2010 {
|
|
|
2011 /* The fully-local case: candidates that need to be
|
|
|
2012 rematerialized after a previous call in the block. */
|
|
|
2013 restrict_remat_for_call (m_required, last_call);
|
|
|
2014 emit_remat_insns (m_required, NULL, info->rd_after_call,
|
|
|
2015 last_call);
|
|
|
2016 }
|
|
131
|
2017 last_call = insn;
|
|
|
2018 bitmap_clear (m_available);
|
|
|
2019 gcc_checking_assert (empty_p (m_required));
|
|
|
2020 }
|
|
|
2021
|
|
|
2022 /* Now process definitions. */
|
|
|
2023 if (next_def && insn == next_def->insn)
|
|
|
2024 {
|
|
|
2025 unsigned int gen = canon_candidate (next_candidate);
|
|
|
2026
|
|
|
2027 /* Other candidates with the same regno are not available
|
|
|
2028 any more. */
|
|
|
2029 bitmap kill = m_regno_to_candidates[next_def->regno];
|
|
|
2030 bitmap_and_compl_into (m_available, kill);
|
|
|
2031 bitmap_and_compl_into (&reaching, kill);
|
|
|
2032
|
|
|
2033 /* Record that this candidate is available without
|
|
|
2034 rematerialization. */
|
|
|
2035 bitmap_set_bit (m_available, gen);
|
|
|
2036 bitmap_set_bit (&reaching, gen);
|
|
|
2037
|
|
|
2038 /* Find the next candidate in the block. */
|
|
|
2039 num_candidates -= 1;
|
|
|
2040 next_candidate -= 1;
|
|
|
2041 if (num_candidates > 0)
|
|
|
2042 next_def -= 1;
|
|
|
2043 else
|
|
|
2044 next_def = NULL;
|
|
|
2045 }
|
|
|
2046
|
|
|
2047 if (insn == last_call)
|
|
|
2048 bitmap_copy (get_bitmap (&info->rd_after_call), &reaching);
|
|
|
2049 }
|
|
|
2050 bitmap_clear (&reaching);
|
|
|
2051 gcc_checking_assert (num_candidates == 0);
|
|
|
2052
|
|
|
2053 /* Remove values from the available set if they aren't live (and so
|
|
|
2054 aren't interesting to successor blocks). */
|
|
|
2055 if (info->rd_out)
|
|
|
2056 bitmap_and_into (m_available, info->rd_out);
|
|
|
2057
|
|
|
2058 /* Record the accumulated information. */
|
|
|
2059 info->last_call = last_call;
|
|
|
2060 info->abnormal_call_p = (last_call
|
|
|
2061 && last_call == BB_END (bb)
|
|
|
2062 && has_abnormal_or_eh_outgoing_edge_p (bb));
|
|
|
2063 copy_temp_bitmap (&info->available_locally, &m_available);
|
|
|
2064 if (last_call)
|
|
|
2065 copy_temp_bitmap (&info->required_after_call, &m_required);
|
|
|
2066 else
|
|
|
2067 copy_temp_bitmap (&info->required_in, &m_required);
|
|
|
2068
|
|
|
2069 /* Assume at first that all live-in values are available without
|
|
|
2070 rematerialization (i.e. start with the most optimistic assumption). */
|
|
|
2071 if (info->available_in)
|
|
|
2072 {
|
|
|
2073 if (info->rd_in)
|
|
|
2074 bitmap_copy (info->available_in, info->rd_in);
|
|
|
2075 else
|
|
|
2076 BITMAP_FREE (info->available_in);
|
|
|
2077 }
|
|
|
2078
|
|
|
2079 if (last_call || empty_p (info->available_in))
|
|
|
2080 /* The values available on exit from the block are exactly those that
|
|
|
2081 are available locally. This set doesn't change. */
|
|
|
2082 info->available_out = info->available_locally;
|
|
|
2083 else if (empty_p (info->available_locally) && empty_p (info->rd_kill))
|
|
|
2084 /* The values available on exit are the same as those available on entry.
|
|
|
2085 Updating one updates the other. */
|
|
|
2086 info->available_out = info->available_in;
|
|
|
2087 else
|
|
|
2088 set_available_out (info);
|
|
|
2089 }
|
|
|
2090
|
|
|
2091 /* Process each block as for process_block, visiting dominators before
|
|
|
2092 the blocks they dominate. */
|
|
|
2093
|
|
|
2094 void
|
|
|
2095 early_remat::local_phase (void)
|
|
|
2096 {
|
|
|
2097 if (dump_file)
|
|
|
2098 fprintf (dump_file, "\n;; Local phase:\n");
|
|
|
2099
|
|
|
2100 int *postorder = df_get_postorder (DF_BACKWARD);
|
|
|
2101 unsigned int postorder_len = df_get_n_blocks (DF_BACKWARD);
|
|
|
2102 for (unsigned int i = postorder_len; i-- > 0; )
|
|
|
2103 if (postorder[i] >= NUM_FIXED_BLOCKS)
|
|
|
2104 process_block (BASIC_BLOCK_FOR_FN (m_fn, postorder[i]));
|
|
|
2105 }
|
|
|
2106
|
|
|
2107 /* Return true if available values survive across edge E. */
|
|
|
2108
|
|
|
2109 static inline bool
|
|
|
2110 available_across_edge_p (edge e)
|
|
|
2111 {
|
|
|
2112 return (e->flags & EDGE_EH) == 0;
|
|
|
2113 }
|
|
|
2114
|
|
|
2115 /* Propagate information from the available_out set of E->src to the
|
|
|
2116 available_in set of E->dest, when computing global availability.
|
|
|
2117 Return true if something changed. */
|
|
|
2118
|
|
|
2119 bool
|
|
|
2120 early_remat::avail_confluence_n (edge e)
|
|
|
2121 {
|
|
|
2122 remat_block_info *src = &er->m_block_info[e->src->index];
|
|
|
2123 remat_block_info *dest = &er->m_block_info[e->dest->index];
|
|
|
2124
|
|
|
2125 if (!available_across_edge_p (e))
|
|
|
2126 return false;
|
|
|
2127
|
|
|
2128 if (empty_p (dest->available_in))
|
|
|
2129 return false;
|
|
|
2130
|
|
|
2131 if (!src->available_out)
|
|
|
2132 {
|
|
|
2133 bitmap_clear (dest->available_in);
|
|
|
2134 return true;
|
|
|
2135 }
|
|
|
2136
|
|
|
2137 return bitmap_and_into (dest->available_in, src->available_out);
|
|
|
2138 }
|
|
|
2139
|
|
|
2140 /* Propagate information from the available_in set of block BB_INDEX
|
|
|
2141 to available_out. Return true if something changed. */
|
|
|
2142
|
|
|
2143 bool
|
|
|
2144 early_remat::avail_transfer (int bb_index)
|
|
|
2145 {
|
|
|
2146 remat_block_info *info = &er->m_block_info[bb_index];
|
|
|
2147
|
|
|
2148 if (info->available_out == info->available_locally)
|
|
|
2149 return false;
|
|
|
2150
|
|
|
2151 if (info->available_out == info->available_in)
|
|
|
2152 /* Assume that we are only called if the input changed. */
|
|
|
2153 return true;
|
|
|
2154
|
|
|
2155 return er->set_available_out (info);
|
|
|
2156 }
|
|
|
2157
|
|
|
2158 /* Compute global availability for the function, starting with the local
|
|
|
2159 information computed by local_phase. */
|
|
|
2160
|
|
|
2161 void
|
|
|
2162 early_remat::compute_availability (void)
|
|
|
2163 {
|
|
|
2164 /* We use df_simple_dataflow instead of the lcm routines for three reasons:
|
|
|
2165
|
|
|
2166 (1) it avoids recomputing the traversal order;
|
|
|
2167 (2) many of the sets are likely to be sparse, so we don't necessarily
|
|
|
2168 want to use sbitmaps; and
|
|
|
2169 (3) it means we can avoid creating an explicit kill set for the call. */
|
|
|
2170 er = this;
|
|
|
2171 bitmap_clear (&m_tmp_bitmap);
|
|
|
2172 bitmap_set_range (&m_tmp_bitmap, 0, last_basic_block_for_fn (m_fn));
|
|
|
2173 df_simple_dataflow (DF_FORWARD, NULL, NULL,
|
|
|
2174 avail_confluence_n, avail_transfer,
|
|
|
2175 &m_tmp_bitmap, df_get_postorder (DF_FORWARD),
|
|
|
2176 df_get_n_blocks (DF_FORWARD));
|
|
|
2177 er = 0;
|
|
|
2178
|
|
|
2179 /* Restrict the required_in sets to values that aren't available. */
|
|
|
2180 basic_block bb;
|
|
|
2181 FOR_EACH_BB_FN (bb, m_fn)
|
|
|
2182 {
|
|
|
2183 remat_block_info *info = &m_block_info[bb->index];
|
|
|
2184 if (info->required_in && info->available_in)
|
|
|
2185 bitmap_and_compl_into (info->required_in, info->available_in);
|
|
|
2186 }
|
|
|
2187 }
|
|
|
2188
|
|
|
2189 /* Make sure that INFO's available_out and available_in sets are unique. */
|
|
|
2190
|
|
|
2191 inline void
|
|
|
2192 early_remat::unshare_available_sets (remat_block_info *info)
|
|
|
2193 {
|
|
|
2194 if (info->available_in && info->available_in == info->available_out)
|
|
|
2195 {
|
|
|
2196 info->available_in = alloc_bitmap ();
|
|
|
2197 bitmap_copy (info->available_in, info->available_out);
|
|
|
2198 }
|
|
|
2199 }
|
|
|
2200
|
|
|
2201 /* Return true if it is possible to move rematerializations from the
|
|
|
2202 destination of E to the source of E. */
|
|
|
2203
|
|
|
2204 inline bool
|
|
|
2205 early_remat::can_move_across_edge_p (edge e)
|
|
|
2206 {
|
|
|
2207 return (available_across_edge_p (e)
|
|
|
2208 && !m_block_info[e->src->index].abnormal_call_p);
|
|
|
2209 }
|
|
|
2210
|
|
|
2211 /* Return true if it is cheaper to rematerialize values at the head of
|
|
|
2212 block QUERY_BB_INDEX instead of rematerializing in its predecessors. */
|
|
|
2213
|
|
|
2214 bool
|
|
|
2215 early_remat::local_remat_cheaper_p (unsigned int query_bb_index)
|
|
|
2216 {
|
|
|
2217 if (m_block_info[query_bb_index].remat_frequency_valid_p)
|
|
|
2218 return m_block_info[query_bb_index].local_remat_cheaper_p;
|
|
|
2219
|
|
|
2220 /* Iteratively compute the cost of rematerializing values in the
|
|
|
2221 predecessor blocks, then compare that with the cost of
|
|
|
2222 rematerializing at the head of the block.
|
|
|
2223
|
|
|
2224 A cycle indicates that there is no call on that execution path,
|
|
|
2225 so it isn't necessary to rematerialize on that path. */
|
|
|
2226 auto_vec<basic_block, 16> stack;
|
|
|
2227 stack.quick_push (BASIC_BLOCK_FOR_FN (m_fn, query_bb_index));
|
|
|
2228 while (!stack.is_empty ())
|
|
|
2229 {
|
|
|
2230 basic_block bb = stack.last ();
|
|
|
2231 remat_block_info *info = &m_block_info[bb->index];
|
|
|
2232 if (info->remat_frequency_valid_p)
|
|
|
2233 {
|
|
|
2234 stack.pop ();
|
|
|
2235 continue;
|
|
|
2236 }
|
|
|
2237
|
|
|
2238 info->visited_p = true;
|
|
|
2239 int frequency = 0;
|
|
|
2240 bool can_move_p = true;
|
|
|
2241 edge e;
|
|
|
2242 edge_iterator ei;
|
|
|
2243 FOR_EACH_EDGE (e, ei, bb->preds)
|
|
|
2244 if (!can_move_across_edge_p (e))
|
|
|
2245 {
|
|
|
2246 can_move_p = false;
|
|
|
2247 break;
|
|
|
2248 }
|
|
|
2249 else if (m_block_info[e->src->index].last_call)
|
|
|
2250 /* We'll rematerialize after the call. */
|
|
|
2251 frequency += e->src->count.to_frequency (m_fn);
|
|
|
2252 else if (m_block_info[e->src->index].remat_frequency_valid_p)
|
|
|
2253 /* Add the cost of rematerializing at the head of E->src
|
|
|
2254 or in its predecessors (whichever is cheaper). */
|
|
|
2255 frequency += m_block_info[e->src->index].remat_frequency;
|
|
|
2256 else if (!m_block_info[e->src->index].visited_p)
|
|
|
2257 /* Queue E->src and then revisit this block again. */
|
|
|
2258 stack.safe_push (e->src);
|
|
|
2259
|
|
|
2260 /* Come back to this block later if we need to process some of
|
|
|
2261 its predecessors. */
|
|
|
2262 if (stack.last () != bb)
|
|
|
2263 continue;
|
|
|
2264
|
|
|
2265 /* If rematerializing in and before the block have equal cost, prefer
|
|
|
2266 rematerializing in the block. This should shorten the live range. */
|
|
|
2267 int bb_frequency = bb->count.to_frequency (m_fn);
|
|
|
2268 if (!can_move_p || frequency >= bb_frequency)
|
|
|
2269 {
|
|
|
2270 info->local_remat_cheaper_p = true;
|
|
|
2271 info->remat_frequency = bb_frequency;
|
|
|
2272 }
|
|
|
2273 else
|
|
|
2274 info->remat_frequency = frequency;
|
|
|
2275 info->remat_frequency_valid_p = true;
|
|
|
2276 info->visited_p = false;
|
|
|
2277 if (dump_file)
|
|
|
2278 {
|
|
|
2279 if (!can_move_p)
|
|
|
2280 fprintf (dump_file, ";; Need to rematerialize at the head of"
|
|
|
2281 " block %d; cannot move to predecessors.\n", bb->index);
|
|
|
2282 else
|
|
|
2283 {
|
|
|
2284 fprintf (dump_file, ";; Block %d has frequency %d,"
|
|
|
2285 " rematerializing in predecessors has frequency %d",
|
|
|
2286 bb->index, bb_frequency, frequency);
|
|
|
2287 if (info->local_remat_cheaper_p)
|
|
|
2288 fprintf (dump_file, "; prefer to rematerialize"
|
|
|
2289 " in the block\n");
|
|
|
2290 else
|
|
|
2291 fprintf (dump_file, "; prefer to rematerialize"
|
|
|
2292 " in predecessors\n");
|
|
|
2293 }
|
|
|
2294 }
|
|
|
2295 stack.pop ();
|
|
|
2296 }
|
|
|
2297 return m_block_info[query_bb_index].local_remat_cheaper_p;
|
|
|
2298 }
|
|
|
2299
|
|
|
2300 /* Return true if we cannot rematerialize candidate CAND_INDEX at the head of
|
|
|
2301 block BB_INDEX. */
|
|
|
2302
|
|
|
2303 bool
|
|
|
2304 early_remat::need_to_move_candidate_p (unsigned int bb_index,
|
|
|
2305 unsigned int cand_index)
|
|
|
2306 {
|
|
|
2307 remat_block_info *info = &m_block_info[bb_index];
|
|
|
2308 remat_candidate *cand = &m_candidates[cand_index];
|
|
|
2309 basic_block bb = BASIC_BLOCK_FOR_FN (m_fn, bb_index);
|
|
|
2310
|
|
|
2311 /* If there is more than one reaching definition of REGNO,
|
|
|
2312 we'll need to rematerialize in predecessors instead. */
|
|
|
2313 bitmap_and (&m_tmp_bitmap, info->rd_in, m_regno_to_candidates[cand->regno]);
|
|
|
2314 if (!bitmap_single_bit_set_p (&m_tmp_bitmap))
|
|
|
2315 {
|
|
|
2316 if (dump_file)
|
|
|
2317 fprintf (dump_file, ";; Cannot rematerialize %d at the"
|
|
|
2318 " head of block %d because there is more than one"
|
|
|
2319 " reaching definition of reg %d\n", cand_index,
|
|
|
2320 bb_index, cand->regno);
|
|
|
2321 return true;
|
|
|
2322 }
|
|
|
2323
|
|
|
2324 /* Likewise if rematerializing CAND here would clobber a live register. */
|
|
|
2325 if (cand->clobbers
|
|
|
2326 && bitmap_intersect_p (cand->clobbers, DF_LR_IN (bb)))
|
|
|
2327 {
|
|
|
2328 if (dump_file)
|
|
|
2329 fprintf (dump_file, ";; Cannot rematerialize %d at the"
|
|
|
2330 " head of block %d because it would clobber live"
|
|
|
2331 " registers\n", cand_index, bb_index);
|
|
|
2332 return true;
|
|
|
2333 }
|
|
|
2334
|
|
|
2335 return false;
|
|
|
2336 }
|
|
|
2337
|
|
|
2338 /* Set REQUIRED to the minimum set of candidates that must be rematerialized
|
|
|
2339 in predecessors of block BB_INDEX instead of at the start of the block. */
|
|
|
2340
|
|
|
2341 void
|
|
|
2342 early_remat::compute_minimum_move_set (unsigned int bb_index,
|
|
|
2343 bitmap required)
|
|
|
2344 {
|
|
|
2345 remat_block_info *info = &m_block_info[bb_index];
|
|
|
2346 bitmap_head remaining;
|
|
|
2347
|
|
|
2348 bitmap_clear (required);
|
|
|
2349 bitmap_initialize (&remaining, &m_obstack);
|
|
|
2350 bitmap_copy (&remaining, info->required_in);
|
|
|
2351 while (!bitmap_empty_p (&remaining))
|
|
|
2352 {
|
|
|
2353 unsigned int cand_index = bitmap_first_set_bit (&remaining);
|
|
|
2354 remat_candidate *cand = &m_candidates[cand_index];
|
|
|
2355 bitmap_clear_bit (&remaining, cand_index);
|
|
|
2356
|
|
|
2357 /* Leave invalid candidates where they are. */
|
|
|
2358 if (!cand->can_copy_p)
|
|
|
2359 continue;
|
|
|
2360
|
|
|
2361 /* Decide whether to move this candidate. */
|
|
|
2362 if (!bitmap_bit_p (required, cand_index))
|
|
|
2363 {
|
|
|
2364 if (!need_to_move_candidate_p (bb_index, cand_index))
|
|
|
2365 continue;
|
|
|
2366 bitmap_set_bit (required, cand_index);
|
|
|
2367 }
|
|
|
2368
|
|
|
2369 /* Also move values used by the candidate, so that we don't
|
|
|
2370 rematerialize them twice. */
|
|
|
2371 if (cand->uses)
|
|
|
2372 {
|
|
|
2373 bitmap_ior_and_into (required, cand->uses, info->required_in);
|
|
|
2374 bitmap_ior_and_into (&remaining, cand->uses, info->required_in);
|
|
|
2375 }
|
|
|
2376 }
|
|
|
2377 }
|
|
|
2378
|
|
|
2379 /* Make the predecessors of BB_INDEX rematerialize the candidates in
|
|
|
2380 REQUIRED. Add any blocks whose required_in set changes to
|
|
|
2381 PENDING_BLOCKS. */
|
|
|
2382
|
|
|
2383 void
|
|
|
2384 early_remat::move_to_predecessors (unsigned int bb_index, bitmap required,
|
|
|
2385 bitmap pending_blocks)
|
|
|
2386 {
|
|
|
2387 if (empty_p (required))
|
|
|
2388 return;
|
|
|
2389 remat_block_info *dest_info = &m_block_info[bb_index];
|
|
|
2390 basic_block bb = BASIC_BLOCK_FOR_FN (m_fn, bb_index);
|
|
|
2391 edge e;
|
|
|
2392 edge_iterator ei;
|
|
|
2393 FOR_EACH_EDGE (e, ei, bb->preds)
|
|
|
2394 {
|
|
|
2395 remat_block_info *src_info = &m_block_info[e->src->index];
|
|
|
2396
|
|
|
2397 /* Restrict the set we add to the reaching definitions. */
|
|
|
2398 bitmap_and (&m_tmp_bitmap, required, src_info->rd_out);
|
|
|
2399 if (bitmap_empty_p (&m_tmp_bitmap))
|
|
|
2400 continue;
|
|
|
2401
|
|
|
2402 if (!can_move_across_edge_p (e))
|
|
|
2403 {
|
|
|
2404 /* We can't move the rematerialization and we can't do it at
|
|
|
2405 the start of the block either. In this case we just give up
|
|
|
2406 and rely on spilling to make the values available across E. */
|
|
|
2407 if (dump_file)
|
|
|
2408 {
|
|
|
2409 fprintf (dump_file, ";; Cannot rematerialize the following"
|
|
|
2410 " candidates in block %d:", e->src->index);
|
|
|
2411 dump_candidate_bitmap (required);
|
|
|
2412 fprintf (dump_file, "\n");
|
|
|
2413 }
|
|
|
2414 continue;
|
|
|
2415 }
|
|
|
2416
|
|
|
2417 /* Remove candidates that are already available. */
|
|
|
2418 if (src_info->available_out)
|
|
|
2419 {
|
|
|
2420 bitmap_and_compl_into (&m_tmp_bitmap, src_info->available_out);
|
|
|
2421 if (bitmap_empty_p (&m_tmp_bitmap))
|
|
|
2422 continue;
|
|
|
2423 }
|
|
|
2424
|
|
|
2425 /* Add the remaining candidates to the appropriate required set. */
|
|
|
2426 if (dump_file)
|
|
|
2427 {
|
|
|
2428 fprintf (dump_file, ";; Moving this set from block %d"
|
|
|
2429 " to block %d:", bb_index, e->src->index);
|
|
|
2430 dump_candidate_bitmap (&m_tmp_bitmap);
|
|
|
2431 fprintf (dump_file, "\n");
|
|
|
2432 }
|
|
|
2433 /* If the source block contains a call, we want to rematerialize
|
|
|
2434 after the call, otherwise we want to rematerialize at the start
|
|
|
2435 of the block. */
|
|
|
2436 bitmap src_required = get_bitmap (src_info->last_call
|
|
|
2437 ? &src_info->required_after_call
|
|
|
2438 : &src_info->required_in);
|
|
|
2439 if (bitmap_ior_into (src_required, &m_tmp_bitmap))
|
|
|
2440 {
|
|
|
2441 if (!src_info->last_call)
|
|
|
2442 bitmap_set_bit (pending_blocks, e->src->index);
|
|
|
2443 unshare_available_sets (src_info);
|
|
|
2444 bitmap_ior_into (get_bitmap (&src_info->available_out),
|
|
|
2445 &m_tmp_bitmap);
|
|
|
2446 }
|
|
|
2447 }
|
|
|
2448
|
|
|
2449 /* The candidates are now available on entry to the block. */
|
|
|
2450 bitmap_and_compl_into (dest_info->required_in, required);
|
|
|
2451 unshare_available_sets (dest_info);
|
|
|
2452 bitmap_ior_into (get_bitmap (&dest_info->available_in), required);
|
|
|
2453 }
|
|
|
2454
|
|
|
2455 /* Go through the candidates that are currently marked as being
|
|
|
2456 rematerialized at the beginning of a block. Decide in each case
|
|
|
2457 whether that's valid and profitable; if it isn't, move the
|
|
|
2458 rematerialization to predecessor blocks instead. */
|
|
|
2459
|
|
|
2460 void
|
|
|
2461 early_remat::choose_rematerialization_points (void)
|
|
|
2462 {
|
|
|
2463 bitmap_head required;
|
|
|
2464 bitmap_head pending_blocks;
|
|
|
2465
|
|
|
2466 int *postorder = df_get_postorder (DF_BACKWARD);
|
|
|
2467 unsigned int postorder_len = df_get_n_blocks (DF_BACKWARD);
|
|
|
2468 bitmap_initialize (&required, &m_obstack);
|
|
|
2469 bitmap_initialize (&pending_blocks, &m_obstack);
|
|
|
2470 do
|
|
|
2471 /* Process the blocks in postorder, to reduce the number of iterations
|
|
|
2472 of the outer loop. */
|
|
|
2473 for (unsigned int i = 0; i < postorder_len; ++i)
|
|
|
2474 {
|
|
|
2475 unsigned int bb_index = postorder[i];
|
|
|
2476 remat_block_info *info = &m_block_info[bb_index];
|
|
|
2477 bitmap_clear_bit (&pending_blocks, bb_index);
|
|
|
2478
|
|
|
2479 if (empty_p (info->required_in))
|
|
|
2480 continue;
|
|
|
2481
|
|
|
2482 if (info->available_in)
|
|
|
2483 gcc_checking_assert (!bitmap_intersect_p (info->required_in,
|
|
|
2484 info->available_in));
|
|
|
2485
|
|
|
2486 if (local_remat_cheaper_p (bb_index))
|
|
|
2487 {
|
|
|
2488 /* We'd prefer to rematerialize at the head of the block.
|
|
|
2489 Only move candidates if we need to. */
|
|
|
2490 compute_minimum_move_set (bb_index, &required);
|
|
|
2491 move_to_predecessors (bb_index, &required, &pending_blocks);
|
|
|
2492 }
|
|
|
2493 else
|
|
|
2494 move_to_predecessors (bb_index, info->required_in,
|
|
|
2495 &pending_blocks);
|
|
|
2496 }
|
|
|
2497 while (!bitmap_empty_p (&pending_blocks));
|
|
|
2498 bitmap_clear (&required);
|
|
|
2499 }
|
|
|
2500
|
|
|
2501 /* Emit all rematerialization instructions queued for BB. */
|
|
|
2502
|
|
|
2503 void
|
|
|
2504 early_remat::emit_remat_insns_for_block (basic_block bb)
|
|
|
2505 {
|
|
|
2506 remat_block_info *info = &m_block_info[bb->index];
|
|
|
2507
|
|
|
2508 if (info->last_call && !empty_p (info->required_after_call))
|
|
145
|
2509 {
|
|
|
2510 restrict_remat_for_call (info->required_after_call, info->last_call);
|
|
|
2511 emit_remat_insns (info->required_after_call, NULL,
|
|
|
2512 info->rd_after_call, info->last_call);
|
|
|
2513 }
|
|
131
|
2514
|
|
|
2515 if (!empty_p (info->required_in))
|
|
|
2516 {
|
|
|
2517 rtx_insn *insn = BB_HEAD (bb);
|
|
|
2518 while (insn != BB_END (bb)
|
|
|
2519 && !INSN_P (NEXT_INSN (insn)))
|
|
|
2520 insn = NEXT_INSN (insn);
|
|
145
|
2521 restrict_remat_for_unavail_regs (info->required_in, DF_LR_IN (bb));
|
|
131
|
2522 emit_remat_insns (info->required_in, info->available_in,
|
|
|
2523 info->rd_in, insn);
|
|
|
2524 }
|
|
|
2525 }
|
|
|
2526
|
|
|
2527 /* Decide which candidates in each block's REQUIRED_IN set need to be
|
|
|
2528 rematerialized and decide where the rematerialization instructions
|
|
|
2529 should go. Emit queued rematerialization instructions at the start
|
|
|
2530 of blocks and after the last calls in blocks. */
|
|
|
2531
|
|
|
2532 void
|
|
|
2533 early_remat::global_phase (void)
|
|
|
2534 {
|
|
|
2535 compute_availability ();
|
|
|
2536 if (dump_file)
|
|
|
2537 {
|
|
|
2538 fprintf (dump_file, "\n;; Blocks after computing global"
|
|
|
2539 " availability:\n");
|
|
|
2540 dump_all_blocks ();
|
|
|
2541 }
|
|
|
2542
|
|
|
2543 choose_rematerialization_points ();
|
|
|
2544 if (dump_file)
|
|
|
2545 {
|
|
|
2546 fprintf (dump_file, "\n;; Blocks after choosing rematerialization"
|
|
|
2547 " points:\n");
|
|
|
2548 dump_all_blocks ();
|
|
|
2549 }
|
|
|
2550
|
|
|
2551 basic_block bb;
|
|
|
2552 FOR_EACH_BB_FN (bb, m_fn)
|
|
|
2553 emit_remat_insns_for_block (bb);
|
|
|
2554 }
|
|
|
2555
|
|
|
2556 /* Main function for the pass. */
|
|
|
2557
|
|
|
2558 void
|
|
|
2559 early_remat::run (void)
|
|
|
2560 {
|
|
|
2561 df_analyze ();
|
|
|
2562
|
|
|
2563 if (!collect_candidates ())
|
|
|
2564 return;
|
|
|
2565
|
|
|
2566 init_block_info ();
|
|
|
2567 sort_candidates ();
|
|
|
2568 finalize_candidate_indices ();
|
|
|
2569 if (dump_file)
|
|
|
2570 dump_all_candidates ();
|
|
|
2571
|
|
|
2572 compute_rd ();
|
|
|
2573 decide_candidate_validity ();
|
|
|
2574 local_phase ();
|
|
|
2575 global_phase ();
|
|
|
2576 }
|
|
|
2577
|
|
|
2578 early_remat::early_remat (function *fn, sbitmap selected_modes)
|
|
|
2579 : m_fn (fn),
|
|
|
2580 m_selected_modes (selected_modes),
|
|
|
2581 m_available (0),
|
|
|
2582 m_required (0),
|
|
|
2583 m_value_table (63)
|
|
|
2584 {
|
|
|
2585 bitmap_obstack_initialize (&m_obstack);
|
|
|
2586 bitmap_initialize (&m_candidate_regnos, &m_obstack);
|
|
|
2587 bitmap_initialize (&m_tmp_bitmap, &m_obstack);
|
|
|
2588 }
|
|
|
2589
|
|
|
2590 early_remat::~early_remat ()
|
|
|
2591 {
|
|
|
2592 bitmap_obstack_release (&m_obstack);
|
|
|
2593 }
|
|
|
2594
|
|
|
2595 namespace {
|
|
|
2596
|
|
|
2597 const pass_data pass_data_early_remat =
|
|
|
2598 {
|
|
|
2599 RTL_PASS, /* type */
|
|
|
2600 "early_remat", /* name */
|
|
|
2601 OPTGROUP_NONE, /* optinfo_flags */
|
|
|
2602 TV_EARLY_REMAT, /* tv_id */
|
|
|
2603 0, /* properties_required */
|
|
|
2604 0, /* properties_provided */
|
|
|
2605 0, /* properties_destroyed */
|
|
|
2606 0, /* todo_flags_start */
|
|
|
2607 TODO_df_finish, /* todo_flags_finish */
|
|
|
2608 };
|
|
|
2609
|
|
|
2610 class pass_early_remat : public rtl_opt_pass
|
|
|
2611 {
|
|
|
2612 public:
|
|
|
2613 pass_early_remat (gcc::context *ctxt)
|
|
|
2614 : rtl_opt_pass (pass_data_early_remat, ctxt)
|
|
|
2615 {}
|
|
|
2616
|
|
|
2617 /* opt_pass methods: */
|
|
|
2618 virtual bool gate (function *)
|
|
|
2619 {
|
|
|
2620 return optimize > 1 && NUM_POLY_INT_COEFFS > 1;
|
|
|
2621 }
|
|
|
2622
|
|
|
2623 virtual unsigned int execute (function *f)
|
|
|
2624 {
|
|
|
2625 auto_sbitmap selected_modes (NUM_MACHINE_MODES);
|
|
|
2626 bitmap_clear (selected_modes);
|
|
|
2627 targetm.select_early_remat_modes (selected_modes);
|
|
|
2628 if (!bitmap_empty_p (selected_modes))
|
|
|
2629 early_remat (f, selected_modes).run ();
|
|
|
2630 return 0;
|
|
|
2631 }
|
|
|
2632 }; // class pass_early_remat
|
|
|
2633
|
|
|
2634 } // anon namespace
|
|
|
2635
|
|
|
2636 rtl_opt_pass *
|
|
|
2637 make_pass_early_remat (gcc::context *ctxt)
|
|
|
2638 {
|
|
|
2639 return new pass_early_remat (ctxt);
|
|
|
2640 }
|
