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