1 | /* Allocate registers for pseudo-registers that span basic blocks. |
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2 | Copyright (C) 1987, 1988, 1991, 1994 Free Software Foundation, Inc. |
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3 | |
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4 | This file is part of GNU CC. |
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5 | |
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6 | GNU CC is free software; you can redistribute it and/or modify |
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7 | it under the terms of the GNU General Public License as published by |
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8 | the Free Software Foundation; either version 2, or (at your option) |
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9 | any later version. |
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10 | |
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11 | GNU CC is distributed in the hope that it will be useful, |
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12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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14 | GNU General Public License 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 GNU CC; see the file COPYING. If not, write to |
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18 | the Free Software Foundation, 59 Temple Place - Suite 330, |
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19 | Boston, MA 02111-1307, USA. */ |
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20 | |
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21 | |
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22 | #include <stdio.h> |
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23 | #include "config.h" |
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24 | #include "rtl.h" |
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25 | #include "flags.h" |
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26 | #include "basic-block.h" |
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27 | #include "hard-reg-set.h" |
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28 | #include "regs.h" |
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29 | #include "insn-config.h" |
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30 | #include "output.h" |
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31 | |
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32 | /* This pass of the compiler performs global register allocation. |
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33 | It assigns hard register numbers to all the pseudo registers |
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34 | that were not handled in local_alloc. Assignments are recorded |
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35 | in the vector reg_renumber, not by changing the rtl code. |
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36 | (Such changes are made by final). The entry point is |
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37 | the function global_alloc. |
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38 | |
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39 | After allocation is complete, the reload pass is run as a subroutine |
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40 | of this pass, so that when a pseudo reg loses its hard reg due to |
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41 | spilling it is possible to make a second attempt to find a hard |
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42 | reg for it. The reload pass is independent in other respects |
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43 | and it is run even when stupid register allocation is in use. |
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44 | |
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45 | 1. count the pseudo-registers still needing allocation |
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46 | and assign allocation-numbers (allocnos) to them. |
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47 | Set up tables reg_allocno and allocno_reg to map |
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48 | reg numbers to allocnos and vice versa. |
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49 | max_allocno gets the number of allocnos in use. |
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50 | |
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51 | 2. Allocate a max_allocno by max_allocno conflict bit matrix and clear it. |
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52 | Allocate a max_allocno by FIRST_PSEUDO_REGISTER conflict matrix |
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53 | for conflicts between allocnos and explicit hard register use |
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54 | (which includes use of pseudo-registers allocated by local_alloc). |
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55 | |
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56 | 3. for each basic block |
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57 | walk forward through the block, recording which |
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58 | unallocated registers and which hardware registers are live. |
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59 | Build the conflict matrix between the unallocated registers |
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60 | and another of unallocated registers versus hardware registers. |
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61 | Also record the preferred hardware registers |
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62 | for each unallocated one. |
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63 | |
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64 | 4. Sort a table of the allocnos into order of |
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65 | desirability of the variables. |
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66 | |
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67 | 5. Allocate the variables in that order; each if possible into |
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68 | a preferred register, else into another register. */ |
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69 | |
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70 | /* Number of pseudo-registers still requiring allocation |
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71 | (not allocated by local_allocate). */ |
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72 | |
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73 | static int max_allocno; |
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74 | |
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75 | /* Indexed by (pseudo) reg number, gives the allocno, or -1 |
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76 | for pseudo registers already allocated by local_allocate. */ |
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77 | |
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78 | static int *reg_allocno; |
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79 | |
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80 | /* Indexed by allocno, gives the reg number. */ |
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81 | |
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82 | static int *allocno_reg; |
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83 | |
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84 | /* A vector of the integers from 0 to max_allocno-1, |
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85 | sorted in the order of first-to-be-allocated first. */ |
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86 | |
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87 | static int *allocno_order; |
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88 | |
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89 | /* Indexed by an allocno, gives the number of consecutive |
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90 | hard registers needed by that pseudo reg. */ |
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91 | |
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92 | static int *allocno_size; |
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93 | |
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94 | /* Indexed by (pseudo) reg number, gives the number of another |
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95 | lower-numbered pseudo reg which can share a hard reg with this pseudo |
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96 | *even if the two pseudos would otherwise appear to conflict*. */ |
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97 | |
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98 | static int *reg_may_share; |
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99 | |
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100 | /* Define the number of bits in each element of `conflicts' and what |
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101 | type that element has. We use the largest integer format on the |
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102 | host machine. */ |
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103 | |
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104 | #define INT_BITS HOST_BITS_PER_WIDE_INT |
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105 | #define INT_TYPE HOST_WIDE_INT |
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106 | |
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107 | /* max_allocno by max_allocno array of bits, |
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108 | recording whether two allocno's conflict (can't go in the same |
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109 | hardware register). |
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110 | |
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111 | `conflicts' is not symmetric; a conflict between allocno's i and j |
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112 | is recorded either in element i,j or in element j,i. */ |
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113 | |
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114 | static INT_TYPE *conflicts; |
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115 | |
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116 | /* Number of ints require to hold max_allocno bits. |
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117 | This is the length of a row in `conflicts'. */ |
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118 | |
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119 | static int allocno_row_words; |
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120 | |
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121 | /* Two macros to test or store 1 in an element of `conflicts'. */ |
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122 | |
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123 | #define CONFLICTP(I, J) \ |
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124 | (conflicts[(I) * allocno_row_words + (J) / INT_BITS] \ |
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125 | & ((INT_TYPE) 1 << ((J) % INT_BITS))) |
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126 | |
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127 | #define SET_CONFLICT(I, J) \ |
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128 | (conflicts[(I) * allocno_row_words + (J) / INT_BITS] \ |
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129 | |= ((INT_TYPE) 1 << ((J) % INT_BITS))) |
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130 | |
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131 | /* Set of hard regs currently live (during scan of all insns). */ |
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132 | |
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133 | static HARD_REG_SET hard_regs_live; |
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134 | |
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135 | /* Indexed by N, set of hard regs conflicting with allocno N. */ |
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136 | |
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137 | static HARD_REG_SET *hard_reg_conflicts; |
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138 | |
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139 | /* Indexed by N, set of hard regs preferred by allocno N. |
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140 | This is used to make allocnos go into regs that are copied to or from them, |
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141 | when possible, to reduce register shuffling. */ |
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142 | |
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143 | static HARD_REG_SET *hard_reg_preferences; |
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144 | |
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145 | /* Similar, but just counts register preferences made in simple copy |
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146 | operations, rather than arithmetic. These are given priority because |
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147 | we can always eliminate an insn by using these, but using a register |
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148 | in the above list won't always eliminate an insn. */ |
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149 | |
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150 | static HARD_REG_SET *hard_reg_copy_preferences; |
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151 | |
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152 | /* Similar to hard_reg_preferences, but includes bits for subsequent |
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153 | registers when an allocno is multi-word. The above variable is used for |
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154 | allocation while this is used to build reg_someone_prefers, below. */ |
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155 | |
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156 | static HARD_REG_SET *hard_reg_full_preferences; |
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157 | |
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158 | /* Indexed by N, set of hard registers that some later allocno has a |
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159 | preference for. */ |
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160 | |
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161 | static HARD_REG_SET *regs_someone_prefers; |
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162 | |
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163 | /* Set of registers that global-alloc isn't supposed to use. */ |
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164 | |
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165 | static HARD_REG_SET no_global_alloc_regs; |
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166 | |
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167 | /* Set of registers used so far. */ |
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168 | |
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169 | static HARD_REG_SET regs_used_so_far; |
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170 | |
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171 | /* Number of calls crossed by each allocno. */ |
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172 | |
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173 | static int *allocno_calls_crossed; |
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174 | |
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175 | /* Number of refs (weighted) to each allocno. */ |
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176 | |
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177 | static int *allocno_n_refs; |
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178 | |
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179 | /* Guess at live length of each allocno. |
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180 | This is actually the max of the live lengths of the regs. */ |
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181 | |
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182 | static int *allocno_live_length; |
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183 | |
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184 | /* Number of refs (weighted) to each hard reg, as used by local alloc. |
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185 | It is zero for a reg that contains global pseudos or is explicitly used. */ |
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186 | |
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187 | static int local_reg_n_refs[FIRST_PSEUDO_REGISTER]; |
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188 | |
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189 | /* Guess at live length of each hard reg, as used by local alloc. |
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190 | This is actually the sum of the live lengths of the specific regs. */ |
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191 | |
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192 | static int local_reg_live_length[FIRST_PSEUDO_REGISTER]; |
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193 | |
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194 | /* Test a bit in TABLE, a vector of HARD_REG_SETs, |
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195 | for vector element I, and hard register number J. */ |
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196 | |
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197 | #define REGBITP(TABLE, I, J) TEST_HARD_REG_BIT (TABLE[I], J) |
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198 | |
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199 | /* Set to 1 a bit in a vector of HARD_REG_SETs. Works like REGBITP. */ |
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200 | |
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201 | #define SET_REGBIT(TABLE, I, J) SET_HARD_REG_BIT (TABLE[I], J) |
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202 | |
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203 | /* Bit mask for allocnos live at current point in the scan. */ |
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204 | |
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205 | static INT_TYPE *allocnos_live; |
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206 | |
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207 | /* Test, set or clear bit number I in allocnos_live, |
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208 | a bit vector indexed by allocno. */ |
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209 | |
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210 | #define ALLOCNO_LIVE_P(I) \ |
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211 | (allocnos_live[(I) / INT_BITS] & ((INT_TYPE) 1 << ((I) % INT_BITS))) |
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212 | |
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213 | #define SET_ALLOCNO_LIVE(I) \ |
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214 | (allocnos_live[(I) / INT_BITS] |= ((INT_TYPE) 1 << ((I) % INT_BITS))) |
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215 | |
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216 | #define CLEAR_ALLOCNO_LIVE(I) \ |
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217 | (allocnos_live[(I) / INT_BITS] &= ~((INT_TYPE) 1 << ((I) % INT_BITS))) |
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218 | |
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219 | /* This is turned off because it doesn't work right for DImode. |
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220 | (And it is only used for DImode, so the other cases are worthless.) |
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221 | The problem is that it isn't true that there is NO possibility of conflict; |
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222 | only that there is no conflict if the two pseudos get the exact same regs. |
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223 | If they were allocated with a partial overlap, there would be a conflict. |
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224 | We can't safely turn off the conflict unless we have another way to |
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225 | prevent the partial overlap. |
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226 | |
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227 | Idea: change hard_reg_conflicts so that instead of recording which |
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228 | hard regs the allocno may not overlap, it records where the allocno |
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229 | may not start. Change both where it is used and where it is updated. |
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230 | Then there is a way to record that (reg:DI 108) may start at 10 |
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231 | but not at 9 or 11. There is still the question of how to record |
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232 | this semi-conflict between two pseudos. */ |
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233 | #if 0 |
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234 | /* Reg pairs for which conflict after the current insn |
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235 | is inhibited by a REG_NO_CONFLICT note. |
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236 | If the table gets full, we ignore any other notes--that is conservative. */ |
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237 | #define NUM_NO_CONFLICT_PAIRS 4 |
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238 | /* Number of pairs in use in this insn. */ |
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239 | int n_no_conflict_pairs; |
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240 | static struct { int allocno1, allocno2;} |
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241 | no_conflict_pairs[NUM_NO_CONFLICT_PAIRS]; |
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242 | #endif /* 0 */ |
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243 | |
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244 | /* Record all regs that are set in any one insn. |
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245 | Communication from mark_reg_{store,clobber} and global_conflicts. */ |
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246 | |
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247 | static rtx *regs_set; |
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248 | static int n_regs_set; |
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249 | |
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250 | /* All registers that can be eliminated. */ |
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251 | |
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252 | static HARD_REG_SET eliminable_regset; |
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253 | |
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254 | static int allocno_compare PROTO((int *, int *)); |
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255 | static void global_conflicts PROTO((void)); |
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256 | static void expand_preferences PROTO((void)); |
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257 | static void prune_preferences PROTO((void)); |
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258 | static void find_reg PROTO((int, HARD_REG_SET, int, int, int)); |
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259 | static void record_one_conflict PROTO((int)); |
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260 | static void record_conflicts PROTO((short *, int)); |
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261 | static void mark_reg_store PROTO((rtx, rtx)); |
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262 | static void mark_reg_clobber PROTO((rtx, rtx)); |
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263 | static void mark_reg_conflicts PROTO((rtx)); |
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264 | static void mark_reg_death PROTO((rtx)); |
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265 | static void mark_reg_live_nc PROTO((int, enum machine_mode)); |
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266 | static void set_preference PROTO((rtx, rtx)); |
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267 | static void dump_conflicts PROTO((FILE *)); |
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268 | |
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269 | /* Perform allocation of pseudo-registers not allocated by local_alloc. |
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270 | FILE is a file to output debugging information on, |
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271 | or zero if such output is not desired. |
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272 | |
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273 | Return value is nonzero if reload failed |
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274 | and we must not do any more for this function. */ |
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275 | |
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276 | int |
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277 | global_alloc (file) |
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278 | FILE *file; |
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279 | { |
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280 | #ifdef ELIMINABLE_REGS |
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281 | static struct {int from, to; } eliminables[] = ELIMINABLE_REGS; |
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282 | #endif |
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283 | int need_fp |
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284 | = (! flag_omit_frame_pointer |
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285 | #ifdef EXIT_IGNORE_STACK |
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286 | || (current_function_calls_alloca && EXIT_IGNORE_STACK) |
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287 | #endif |
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288 | || FRAME_POINTER_REQUIRED); |
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289 | |
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290 | register int i; |
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291 | rtx x; |
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292 | |
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293 | max_allocno = 0; |
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294 | |
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295 | /* A machine may have certain hard registers that |
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296 | are safe to use only within a basic block. */ |
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297 | |
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298 | CLEAR_HARD_REG_SET (no_global_alloc_regs); |
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299 | #ifdef OVERLAPPING_REGNO_P |
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300 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
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301 | if (OVERLAPPING_REGNO_P (i)) |
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302 | SET_HARD_REG_BIT (no_global_alloc_regs, i); |
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303 | #endif |
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304 | |
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305 | /* Build the regset of all eliminable registers and show we can't use those |
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306 | that we already know won't be eliminated. */ |
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307 | #ifdef ELIMINABLE_REGS |
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308 | for (i = 0; i < sizeof eliminables / sizeof eliminables[0]; i++) |
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309 | { |
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310 | SET_HARD_REG_BIT (eliminable_regset, eliminables[i].from); |
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311 | |
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312 | if (! CAN_ELIMINATE (eliminables[i].from, eliminables[i].to) |
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313 | || (eliminables[i].to == STACK_POINTER_REGNUM && need_fp)) |
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314 | SET_HARD_REG_BIT (no_global_alloc_regs, eliminables[i].from); |
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315 | } |
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316 | #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM |
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317 | SET_HARD_REG_BIT (eliminable_regset, HARD_FRAME_POINTER_REGNUM); |
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318 | if (need_fp) |
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319 | SET_HARD_REG_BIT (no_global_alloc_regs, HARD_FRAME_POINTER_REGNUM); |
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320 | #endif |
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321 | |
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322 | #else |
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323 | SET_HARD_REG_BIT (eliminable_regset, FRAME_POINTER_REGNUM); |
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324 | if (need_fp) |
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325 | SET_HARD_REG_BIT (no_global_alloc_regs, FRAME_POINTER_REGNUM); |
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326 | #endif |
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327 | |
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328 | /* Track which registers have already been used. Start with registers |
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329 | explicitly in the rtl, then registers allocated by local register |
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330 | allocation. */ |
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331 | |
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332 | CLEAR_HARD_REG_SET (regs_used_so_far); |
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333 | #ifdef LEAF_REGISTERS |
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334 | /* If we are doing the leaf function optimization, and this is a leaf |
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335 | function, it means that the registers that take work to save are those |
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336 | that need a register window. So prefer the ones that can be used in |
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337 | a leaf function. */ |
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338 | { |
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339 | char *cheap_regs; |
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340 | static char leaf_regs[] = LEAF_REGISTERS; |
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341 | |
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342 | if (only_leaf_regs_used () && leaf_function_p ()) |
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343 | cheap_regs = leaf_regs; |
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344 | else |
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345 | cheap_regs = call_used_regs; |
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346 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
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347 | if (regs_ever_live[i] || cheap_regs[i]) |
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348 | SET_HARD_REG_BIT (regs_used_so_far, i); |
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349 | } |
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350 | #else |
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351 | /* We consider registers that do not have to be saved over calls as if |
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352 | they were already used since there is no cost in using them. */ |
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353 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
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354 | if (regs_ever_live[i] || call_used_regs[i]) |
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355 | SET_HARD_REG_BIT (regs_used_so_far, i); |
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356 | #endif |
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357 | |
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358 | for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) |
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359 | if (reg_renumber[i] >= 0) |
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360 | SET_HARD_REG_BIT (regs_used_so_far, reg_renumber[i]); |
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361 | |
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362 | /* Establish mappings from register number to allocation number |
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363 | and vice versa. In the process, count the allocnos. */ |
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364 | |
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365 | reg_allocno = (int *) alloca (max_regno * sizeof (int)); |
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366 | |
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367 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
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368 | reg_allocno[i] = -1; |
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369 | |
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370 | /* Initialize the shared-hard-reg mapping |
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371 | from the list of pairs that may share. */ |
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372 | reg_may_share = (int *) alloca (max_regno * sizeof (int)); |
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373 | bzero ((char *) reg_may_share, max_regno * sizeof (int)); |
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374 | for (x = regs_may_share; x; x = XEXP (XEXP (x, 1), 1)) |
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375 | { |
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376 | int r1 = REGNO (XEXP (x, 0)); |
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377 | int r2 = REGNO (XEXP (XEXP (x, 1), 0)); |
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378 | if (r1 > r2) |
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379 | reg_may_share[r1] = r2; |
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380 | else |
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381 | reg_may_share[r2] = r1; |
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382 | } |
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383 | |
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384 | for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) |
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385 | /* Note that reg_live_length[i] < 0 indicates a "constant" reg |
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386 | that we are supposed to refrain from putting in a hard reg. |
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387 | -2 means do make an allocno but don't allocate it. */ |
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388 | if (reg_n_refs[i] != 0 && reg_renumber[i] < 0 && reg_live_length[i] != -1 |
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389 | /* Don't allocate pseudos that cross calls, |
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390 | if this function receives a nonlocal goto. */ |
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391 | && (! current_function_has_nonlocal_label |
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392 | || reg_n_calls_crossed[i] == 0)) |
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393 | { |
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394 | if (reg_may_share[i] && reg_allocno[reg_may_share[i]] >= 0) |
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395 | reg_allocno[i] = reg_allocno[reg_may_share[i]]; |
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396 | else |
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397 | reg_allocno[i] = max_allocno++; |
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398 | if (reg_live_length[i] == 0) |
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399 | abort (); |
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400 | } |
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401 | else |
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402 | reg_allocno[i] = -1; |
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403 | |
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404 | allocno_reg = (int *) alloca (max_allocno * sizeof (int)); |
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405 | allocno_size = (int *) alloca (max_allocno * sizeof (int)); |
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406 | allocno_calls_crossed = (int *) alloca (max_allocno * sizeof (int)); |
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407 | allocno_n_refs = (int *) alloca (max_allocno * sizeof (int)); |
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408 | allocno_live_length = (int *) alloca (max_allocno * sizeof (int)); |
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409 | bzero ((char *) allocno_size, max_allocno * sizeof (int)); |
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410 | bzero ((char *) allocno_calls_crossed, max_allocno * sizeof (int)); |
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411 | bzero ((char *) allocno_n_refs, max_allocno * sizeof (int)); |
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412 | bzero ((char *) allocno_live_length, max_allocno * sizeof (int)); |
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413 | |
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414 | for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) |
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415 | if (reg_allocno[i] >= 0) |
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416 | { |
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417 | int allocno = reg_allocno[i]; |
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418 | allocno_reg[allocno] = i; |
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419 | allocno_size[allocno] = PSEUDO_REGNO_SIZE (i); |
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420 | allocno_calls_crossed[allocno] += reg_n_calls_crossed[i]; |
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421 | allocno_n_refs[allocno] += reg_n_refs[i]; |
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422 | if (allocno_live_length[allocno] < reg_live_length[i]) |
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423 | allocno_live_length[allocno] = reg_live_length[i]; |
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424 | } |
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425 | |
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426 | /* Calculate amount of usage of each hard reg by pseudos |
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427 | allocated by local-alloc. This is to see if we want to |
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428 | override it. */ |
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429 | bzero ((char *) local_reg_live_length, sizeof local_reg_live_length); |
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430 | bzero ((char *) local_reg_n_refs, sizeof local_reg_n_refs); |
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431 | for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) |
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432 | if (reg_allocno[i] < 0 && reg_renumber[i] >= 0) |
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433 | { |
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434 | int regno = reg_renumber[i]; |
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435 | int endregno = regno + HARD_REGNO_NREGS (regno, PSEUDO_REGNO_MODE (i)); |
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436 | int j; |
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437 | |
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438 | for (j = regno; j < endregno; j++) |
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439 | { |
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440 | local_reg_n_refs[j] += reg_n_refs[i]; |
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441 | local_reg_live_length[j] += reg_live_length[i]; |
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442 | } |
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443 | } |
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444 | |
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445 | /* We can't override local-alloc for a reg used not just by local-alloc. */ |
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446 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
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447 | if (regs_ever_live[i]) |
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448 | local_reg_n_refs[i] = 0; |
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449 | |
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450 | /* Likewise for regs used in a SCRATCH. */ |
---|
451 | for (i = 0; i < scratch_list_length; i++) |
---|
452 | if (scratch_list[i]) |
---|
453 | { |
---|
454 | int regno = REGNO (scratch_list[i]); |
---|
455 | int lim = regno + HARD_REGNO_NREGS (regno, GET_MODE (scratch_list[i])); |
---|
456 | int j; |
---|
457 | |
---|
458 | for (j = regno; j < lim; j++) |
---|
459 | local_reg_n_refs[j] = 0; |
---|
460 | } |
---|
461 | |
---|
462 | /* Allocate the space for the conflict and preference tables and |
---|
463 | initialize them. */ |
---|
464 | |
---|
465 | hard_reg_conflicts |
---|
466 | = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET)); |
---|
467 | bzero ((char *) hard_reg_conflicts, max_allocno * sizeof (HARD_REG_SET)); |
---|
468 | |
---|
469 | hard_reg_preferences |
---|
470 | = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET)); |
---|
471 | bzero ((char *) hard_reg_preferences, max_allocno * sizeof (HARD_REG_SET)); |
---|
472 | |
---|
473 | hard_reg_copy_preferences |
---|
474 | = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET)); |
---|
475 | bzero ((char *) hard_reg_copy_preferences, |
---|
476 | max_allocno * sizeof (HARD_REG_SET)); |
---|
477 | |
---|
478 | hard_reg_full_preferences |
---|
479 | = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET)); |
---|
480 | bzero ((char *) hard_reg_full_preferences, |
---|
481 | max_allocno * sizeof (HARD_REG_SET)); |
---|
482 | |
---|
483 | regs_someone_prefers |
---|
484 | = (HARD_REG_SET *) alloca (max_allocno * sizeof (HARD_REG_SET)); |
---|
485 | bzero ((char *) regs_someone_prefers, max_allocno * sizeof (HARD_REG_SET)); |
---|
486 | |
---|
487 | allocno_row_words = (max_allocno + INT_BITS - 1) / INT_BITS; |
---|
488 | |
---|
489 | conflicts = (INT_TYPE *) alloca (max_allocno * allocno_row_words |
---|
490 | * sizeof (INT_TYPE)); |
---|
491 | bzero ((char *) conflicts, |
---|
492 | max_allocno * allocno_row_words * sizeof (INT_TYPE)); |
---|
493 | |
---|
494 | allocnos_live = (INT_TYPE *) alloca (allocno_row_words * sizeof (INT_TYPE)); |
---|
495 | |
---|
496 | /* If there is work to be done (at least one reg to allocate), |
---|
497 | perform global conflict analysis and allocate the regs. */ |
---|
498 | |
---|
499 | if (max_allocno > 0) |
---|
500 | { |
---|
501 | /* Scan all the insns and compute the conflicts among allocnos |
---|
502 | and between allocnos and hard regs. */ |
---|
503 | |
---|
504 | global_conflicts (); |
---|
505 | |
---|
506 | /* Eliminate conflicts between pseudos and eliminable registers. If |
---|
507 | the register is not eliminated, the pseudo won't really be able to |
---|
508 | live in the eliminable register, so the conflict doesn't matter. |
---|
509 | If we do eliminate the register, the conflict will no longer exist. |
---|
510 | So in either case, we can ignore the conflict. Likewise for |
---|
511 | preferences. */ |
---|
512 | |
---|
513 | for (i = 0; i < max_allocno; i++) |
---|
514 | { |
---|
515 | AND_COMPL_HARD_REG_SET (hard_reg_conflicts[i], eliminable_regset); |
---|
516 | AND_COMPL_HARD_REG_SET (hard_reg_copy_preferences[i], |
---|
517 | eliminable_regset); |
---|
518 | AND_COMPL_HARD_REG_SET (hard_reg_preferences[i], eliminable_regset); |
---|
519 | } |
---|
520 | |
---|
521 | /* Try to expand the preferences by merging them between allocnos. */ |
---|
522 | |
---|
523 | expand_preferences (); |
---|
524 | |
---|
525 | /* Determine the order to allocate the remaining pseudo registers. */ |
---|
526 | |
---|
527 | allocno_order = (int *) alloca (max_allocno * sizeof (int)); |
---|
528 | for (i = 0; i < max_allocno; i++) |
---|
529 | allocno_order[i] = i; |
---|
530 | |
---|
531 | /* Default the size to 1, since allocno_compare uses it to divide by. |
---|
532 | Also convert allocno_live_length of zero to -1. A length of zero |
---|
533 | can occur when all the registers for that allocno have reg_live_length |
---|
534 | equal to -2. In this case, we want to make an allocno, but not |
---|
535 | allocate it. So avoid the divide-by-zero and set it to a low |
---|
536 | priority. */ |
---|
537 | |
---|
538 | for (i = 0; i < max_allocno; i++) |
---|
539 | { |
---|
540 | if (allocno_size[i] == 0) |
---|
541 | allocno_size[i] = 1; |
---|
542 | if (allocno_live_length[i] == 0) |
---|
543 | allocno_live_length[i] = -1; |
---|
544 | } |
---|
545 | |
---|
546 | qsort (allocno_order, max_allocno, sizeof (int), allocno_compare); |
---|
547 | |
---|
548 | prune_preferences (); |
---|
549 | |
---|
550 | if (file) |
---|
551 | dump_conflicts (file); |
---|
552 | |
---|
553 | /* Try allocating them, one by one, in that order, |
---|
554 | except for parameters marked with reg_live_length[regno] == -2. */ |
---|
555 | |
---|
556 | for (i = 0; i < max_allocno; i++) |
---|
557 | if (reg_live_length[allocno_reg[allocno_order[i]]] >= 0) |
---|
558 | { |
---|
559 | /* If we have more than one register class, |
---|
560 | first try allocating in the class that is cheapest |
---|
561 | for this pseudo-reg. If that fails, try any reg. */ |
---|
562 | if (N_REG_CLASSES > 1) |
---|
563 | { |
---|
564 | find_reg (allocno_order[i], HARD_CONST (0), 0, 0, 0); |
---|
565 | if (reg_renumber[allocno_reg[allocno_order[i]]] >= 0) |
---|
566 | continue; |
---|
567 | } |
---|
568 | if (reg_alternate_class (allocno_reg[allocno_order[i]]) != NO_REGS) |
---|
569 | find_reg (allocno_order[i], HARD_CONST (0), 1, 0, 0); |
---|
570 | } |
---|
571 | } |
---|
572 | |
---|
573 | /* Do the reloads now while the allocno data still exist, so that we can |
---|
574 | try to assign new hard regs to any pseudo regs that are spilled. */ |
---|
575 | |
---|
576 | #if 0 /* We need to eliminate regs even if there is no rtl code, |
---|
577 | for the sake of debugging information. */ |
---|
578 | if (n_basic_blocks > 0) |
---|
579 | #endif |
---|
580 | return reload (get_insns (), 1, file); |
---|
581 | } |
---|
582 | |
---|
583 | /* Sort predicate for ordering the allocnos. |
---|
584 | Returns -1 (1) if *v1 should be allocated before (after) *v2. */ |
---|
585 | |
---|
586 | static int |
---|
587 | allocno_compare (v1, v2) |
---|
588 | int *v1, *v2; |
---|
589 | { |
---|
590 | /* Note that the quotient will never be bigger than |
---|
591 | the value of floor_log2 times the maximum number of |
---|
592 | times a register can occur in one insn (surely less than 100). |
---|
593 | Multiplying this by 10000 can't overflow. */ |
---|
594 | register int pri1 |
---|
595 | = (((double) (floor_log2 (allocno_n_refs[*v1]) * allocno_n_refs[*v1]) |
---|
596 | / allocno_live_length[*v1]) |
---|
597 | * 10000 * allocno_size[*v1]); |
---|
598 | register int pri2 |
---|
599 | = (((double) (floor_log2 (allocno_n_refs[*v2]) * allocno_n_refs[*v2]) |
---|
600 | / allocno_live_length[*v2]) |
---|
601 | * 10000 * allocno_size[*v2]); |
---|
602 | if (pri2 - pri1) |
---|
603 | return pri2 - pri1; |
---|
604 | |
---|
605 | /* If regs are equally good, sort by allocno, |
---|
606 | so that the results of qsort leave nothing to chance. */ |
---|
607 | return *v1 - *v2; |
---|
608 | } |
---|
609 | |
---|
610 | /* Scan the rtl code and record all conflicts and register preferences in the |
---|
611 | conflict matrices and preference tables. */ |
---|
612 | |
---|
613 | static void |
---|
614 | global_conflicts () |
---|
615 | { |
---|
616 | register int b, i; |
---|
617 | register rtx insn; |
---|
618 | short *block_start_allocnos; |
---|
619 | |
---|
620 | /* Make a vector that mark_reg_{store,clobber} will store in. */ |
---|
621 | regs_set = (rtx *) alloca (max_parallel * sizeof (rtx) * 2); |
---|
622 | |
---|
623 | block_start_allocnos = (short *) alloca (max_allocno * sizeof (short)); |
---|
624 | |
---|
625 | for (b = 0; b < n_basic_blocks; b++) |
---|
626 | { |
---|
627 | bzero ((char *) allocnos_live, allocno_row_words * sizeof (INT_TYPE)); |
---|
628 | |
---|
629 | /* Initialize table of registers currently live |
---|
630 | to the state at the beginning of this basic block. |
---|
631 | This also marks the conflicts among them. |
---|
632 | |
---|
633 | For pseudo-regs, there is only one bit for each one |
---|
634 | no matter how many hard regs it occupies. |
---|
635 | This is ok; we know the size from PSEUDO_REGNO_SIZE. |
---|
636 | For explicit hard regs, we cannot know the size that way |
---|
637 | since one hard reg can be used with various sizes. |
---|
638 | Therefore, we must require that all the hard regs |
---|
639 | implicitly live as part of a multi-word hard reg |
---|
640 | are explicitly marked in basic_block_live_at_start. */ |
---|
641 | |
---|
642 | { |
---|
643 | register int offset; |
---|
644 | REGSET_ELT_TYPE bit; |
---|
645 | register regset old = basic_block_live_at_start[b]; |
---|
646 | int ax = 0; |
---|
647 | |
---|
648 | #ifdef HARD_REG_SET |
---|
649 | hard_regs_live = old[0]; |
---|
650 | #else |
---|
651 | COPY_HARD_REG_SET (hard_regs_live, old); |
---|
652 | #endif |
---|
653 | for (offset = 0, i = 0; offset < regset_size; offset++) |
---|
654 | if (old[offset] == 0) |
---|
655 | i += REGSET_ELT_BITS; |
---|
656 | else |
---|
657 | for (bit = 1; bit; bit <<= 1, i++) |
---|
658 | { |
---|
659 | if (i >= max_regno) |
---|
660 | break; |
---|
661 | if (old[offset] & bit) |
---|
662 | { |
---|
663 | register int a = reg_allocno[i]; |
---|
664 | if (a >= 0) |
---|
665 | { |
---|
666 | SET_ALLOCNO_LIVE (a); |
---|
667 | block_start_allocnos[ax++] = a; |
---|
668 | } |
---|
669 | else if ((a = reg_renumber[i]) >= 0) |
---|
670 | mark_reg_live_nc (a, PSEUDO_REGNO_MODE (i)); |
---|
671 | } |
---|
672 | } |
---|
673 | |
---|
674 | /* Record that each allocno now live conflicts with each other |
---|
675 | allocno now live, and with each hard reg now live. */ |
---|
676 | |
---|
677 | record_conflicts (block_start_allocnos, ax); |
---|
678 | } |
---|
679 | |
---|
680 | insn = basic_block_head[b]; |
---|
681 | |
---|
682 | /* Scan the code of this basic block, noting which allocnos |
---|
683 | and hard regs are born or die. When one is born, |
---|
684 | record a conflict with all others currently live. */ |
---|
685 | |
---|
686 | while (1) |
---|
687 | { |
---|
688 | register RTX_CODE code = GET_CODE (insn); |
---|
689 | register rtx link; |
---|
690 | |
---|
691 | /* Make regs_set an empty set. */ |
---|
692 | |
---|
693 | n_regs_set = 0; |
---|
694 | |
---|
695 | if (code == INSN || code == CALL_INSN || code == JUMP_INSN) |
---|
696 | { |
---|
697 | |
---|
698 | #if 0 |
---|
699 | int i = 0; |
---|
700 | for (link = REG_NOTES (insn); |
---|
701 | link && i < NUM_NO_CONFLICT_PAIRS; |
---|
702 | link = XEXP (link, 1)) |
---|
703 | if (REG_NOTE_KIND (link) == REG_NO_CONFLICT) |
---|
704 | { |
---|
705 | no_conflict_pairs[i].allocno1 |
---|
706 | = reg_allocno[REGNO (SET_DEST (PATTERN (insn)))]; |
---|
707 | no_conflict_pairs[i].allocno2 |
---|
708 | = reg_allocno[REGNO (XEXP (link, 0))]; |
---|
709 | i++; |
---|
710 | } |
---|
711 | #endif /* 0 */ |
---|
712 | |
---|
713 | /* Mark any registers clobbered by INSN as live, |
---|
714 | so they conflict with the inputs. */ |
---|
715 | |
---|
716 | note_stores (PATTERN (insn), mark_reg_clobber); |
---|
717 | |
---|
718 | /* Mark any registers dead after INSN as dead now. */ |
---|
719 | |
---|
720 | for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) |
---|
721 | if (REG_NOTE_KIND (link) == REG_DEAD) |
---|
722 | mark_reg_death (XEXP (link, 0)); |
---|
723 | |
---|
724 | /* Mark any registers set in INSN as live, |
---|
725 | and mark them as conflicting with all other live regs. |
---|
726 | Clobbers are processed again, so they conflict with |
---|
727 | the registers that are set. */ |
---|
728 | |
---|
729 | note_stores (PATTERN (insn), mark_reg_store); |
---|
730 | |
---|
731 | #ifdef AUTO_INC_DEC |
---|
732 | for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) |
---|
733 | if (REG_NOTE_KIND (link) == REG_INC) |
---|
734 | mark_reg_store (XEXP (link, 0), NULL_RTX); |
---|
735 | #endif |
---|
736 | |
---|
737 | /* If INSN has multiple outputs, then any reg that dies here |
---|
738 | and is used inside of an output |
---|
739 | must conflict with the other outputs. */ |
---|
740 | |
---|
741 | if (GET_CODE (PATTERN (insn)) == PARALLEL && !single_set (insn)) |
---|
742 | for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) |
---|
743 | if (REG_NOTE_KIND (link) == REG_DEAD) |
---|
744 | { |
---|
745 | int used_in_output = 0; |
---|
746 | int i; |
---|
747 | rtx reg = XEXP (link, 0); |
---|
748 | |
---|
749 | for (i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--) |
---|
750 | { |
---|
751 | rtx set = XVECEXP (PATTERN (insn), 0, i); |
---|
752 | if (GET_CODE (set) == SET |
---|
753 | && GET_CODE (SET_DEST (set)) != REG |
---|
754 | && !rtx_equal_p (reg, SET_DEST (set)) |
---|
755 | && reg_overlap_mentioned_p (reg, SET_DEST (set))) |
---|
756 | used_in_output = 1; |
---|
757 | } |
---|
758 | if (used_in_output) |
---|
759 | mark_reg_conflicts (reg); |
---|
760 | } |
---|
761 | |
---|
762 | /* Mark any registers set in INSN and then never used. */ |
---|
763 | |
---|
764 | while (n_regs_set > 0) |
---|
765 | if (find_regno_note (insn, REG_UNUSED, |
---|
766 | REGNO (regs_set[--n_regs_set]))) |
---|
767 | mark_reg_death (regs_set[n_regs_set]); |
---|
768 | } |
---|
769 | |
---|
770 | if (insn == basic_block_end[b]) |
---|
771 | break; |
---|
772 | insn = NEXT_INSN (insn); |
---|
773 | } |
---|
774 | } |
---|
775 | } |
---|
776 | /* Expand the preference information by looking for cases where one allocno |
---|
777 | dies in an insn that sets an allocno. If those two allocnos don't conflict, |
---|
778 | merge any preferences between those allocnos. */ |
---|
779 | |
---|
780 | static void |
---|
781 | expand_preferences () |
---|
782 | { |
---|
783 | rtx insn; |
---|
784 | rtx link; |
---|
785 | rtx set; |
---|
786 | |
---|
787 | /* We only try to handle the most common cases here. Most of the cases |
---|
788 | where this wins are reg-reg copies. */ |
---|
789 | |
---|
790 | for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) |
---|
791 | if (GET_RTX_CLASS (GET_CODE (insn)) == 'i' |
---|
792 | && (set = single_set (insn)) != 0 |
---|
793 | && GET_CODE (SET_DEST (set)) == REG |
---|
794 | && reg_allocno[REGNO (SET_DEST (set))] >= 0) |
---|
795 | for (link = REG_NOTES (insn); link; link = XEXP (link, 1)) |
---|
796 | if (REG_NOTE_KIND (link) == REG_DEAD |
---|
797 | && GET_CODE (XEXP (link, 0)) == REG |
---|
798 | && reg_allocno[REGNO (XEXP (link, 0))] >= 0 |
---|
799 | && ! CONFLICTP (reg_allocno[REGNO (SET_DEST (set))], |
---|
800 | reg_allocno[REGNO (XEXP (link, 0))]) |
---|
801 | && ! CONFLICTP (reg_allocno[REGNO (XEXP (link, 0))], |
---|
802 | reg_allocno[REGNO (SET_DEST (set))])) |
---|
803 | { |
---|
804 | int a1 = reg_allocno[REGNO (SET_DEST (set))]; |
---|
805 | int a2 = reg_allocno[REGNO (XEXP (link, 0))]; |
---|
806 | |
---|
807 | if (XEXP (link, 0) == SET_SRC (set)) |
---|
808 | { |
---|
809 | IOR_HARD_REG_SET (hard_reg_copy_preferences[a1], |
---|
810 | hard_reg_copy_preferences[a2]); |
---|
811 | IOR_HARD_REG_SET (hard_reg_copy_preferences[a2], |
---|
812 | hard_reg_copy_preferences[a1]); |
---|
813 | } |
---|
814 | |
---|
815 | IOR_HARD_REG_SET (hard_reg_preferences[a1], |
---|
816 | hard_reg_preferences[a2]); |
---|
817 | IOR_HARD_REG_SET (hard_reg_preferences[a2], |
---|
818 | hard_reg_preferences[a1]); |
---|
819 | IOR_HARD_REG_SET (hard_reg_full_preferences[a1], |
---|
820 | hard_reg_full_preferences[a2]); |
---|
821 | IOR_HARD_REG_SET (hard_reg_full_preferences[a2], |
---|
822 | hard_reg_full_preferences[a1]); |
---|
823 | } |
---|
824 | } |
---|
825 | |
---|
826 | /* Prune the preferences for global registers to exclude registers that cannot |
---|
827 | be used. |
---|
828 | |
---|
829 | Compute `regs_someone_prefers', which is a bitmask of the hard registers |
---|
830 | that are preferred by conflicting registers of lower priority. If possible, |
---|
831 | we will avoid using these registers. */ |
---|
832 | |
---|
833 | static void |
---|
834 | prune_preferences () |
---|
835 | { |
---|
836 | int i, j; |
---|
837 | int allocno; |
---|
838 | |
---|
839 | /* Scan least most important to most important. |
---|
840 | For each allocno, remove from preferences registers that cannot be used, |
---|
841 | either because of conflicts or register type. Then compute all registers |
---|
842 | preferred by each lower-priority register that conflicts. */ |
---|
843 | |
---|
844 | for (i = max_allocno - 1; i >= 0; i--) |
---|
845 | { |
---|
846 | HARD_REG_SET temp; |
---|
847 | |
---|
848 | allocno = allocno_order[i]; |
---|
849 | COPY_HARD_REG_SET (temp, hard_reg_conflicts[allocno]); |
---|
850 | |
---|
851 | if (allocno_calls_crossed[allocno] == 0) |
---|
852 | IOR_HARD_REG_SET (temp, fixed_reg_set); |
---|
853 | else |
---|
854 | IOR_HARD_REG_SET (temp, call_used_reg_set); |
---|
855 | |
---|
856 | IOR_COMPL_HARD_REG_SET |
---|
857 | (temp, |
---|
858 | reg_class_contents[(int) reg_preferred_class (allocno_reg[allocno])]); |
---|
859 | |
---|
860 | AND_COMPL_HARD_REG_SET (hard_reg_preferences[allocno], temp); |
---|
861 | AND_COMPL_HARD_REG_SET (hard_reg_copy_preferences[allocno], temp); |
---|
862 | AND_COMPL_HARD_REG_SET (hard_reg_full_preferences[allocno], temp); |
---|
863 | |
---|
864 | CLEAR_HARD_REG_SET (regs_someone_prefers[allocno]); |
---|
865 | |
---|
866 | /* Merge in the preferences of lower-priority registers (they have |
---|
867 | already been pruned). If we also prefer some of those registers, |
---|
868 | don't exclude them unless we are of a smaller size (in which case |
---|
869 | we want to give the lower-priority allocno the first chance for |
---|
870 | these registers). */ |
---|
871 | for (j = i + 1; j < max_allocno; j++) |
---|
872 | if (CONFLICTP (allocno, allocno_order[j])) |
---|
873 | { |
---|
874 | COPY_HARD_REG_SET (temp, |
---|
875 | hard_reg_full_preferences[allocno_order[j]]); |
---|
876 | if (allocno_size[allocno_order[j]] <= allocno_size[allocno]) |
---|
877 | AND_COMPL_HARD_REG_SET (temp, |
---|
878 | hard_reg_full_preferences[allocno]); |
---|
879 | |
---|
880 | IOR_HARD_REG_SET (regs_someone_prefers[allocno], temp); |
---|
881 | } |
---|
882 | } |
---|
883 | } |
---|
884 | |
---|
885 | /* Assign a hard register to ALLOCNO; look for one that is the beginning |
---|
886 | of a long enough stretch of hard regs none of which conflicts with ALLOCNO. |
---|
887 | The registers marked in PREFREGS are tried first. |
---|
888 | |
---|
889 | LOSERS, if non-zero, is a HARD_REG_SET indicating registers that cannot |
---|
890 | be used for this allocation. |
---|
891 | |
---|
892 | If ALT_REGS_P is zero, consider only the preferred class of ALLOCNO's reg. |
---|
893 | Otherwise ignore that preferred class and use the alternate class. |
---|
894 | |
---|
895 | If ACCEPT_CALL_CLOBBERED is nonzero, accept a call-clobbered hard reg that |
---|
896 | will have to be saved and restored at calls. |
---|
897 | |
---|
898 | RETRYING is nonzero if this is called from retry_global_alloc. |
---|
899 | |
---|
900 | If we find one, record it in reg_renumber. |
---|
901 | If not, do nothing. */ |
---|
902 | |
---|
903 | static void |
---|
904 | find_reg (allocno, losers, alt_regs_p, accept_call_clobbered, retrying) |
---|
905 | int allocno; |
---|
906 | HARD_REG_SET losers; |
---|
907 | int alt_regs_p; |
---|
908 | int accept_call_clobbered; |
---|
909 | int retrying; |
---|
910 | { |
---|
911 | register int i, best_reg, pass; |
---|
912 | #ifdef HARD_REG_SET |
---|
913 | register /* Declare it register if it's a scalar. */ |
---|
914 | #endif |
---|
915 | HARD_REG_SET used, used1, used2; |
---|
916 | |
---|
917 | enum reg_class class = (alt_regs_p |
---|
918 | ? reg_alternate_class (allocno_reg[allocno]) |
---|
919 | : reg_preferred_class (allocno_reg[allocno])); |
---|
920 | enum machine_mode mode = PSEUDO_REGNO_MODE (allocno_reg[allocno]); |
---|
921 | |
---|
922 | if (accept_call_clobbered) |
---|
923 | COPY_HARD_REG_SET (used1, call_fixed_reg_set); |
---|
924 | else if (allocno_calls_crossed[allocno] == 0) |
---|
925 | COPY_HARD_REG_SET (used1, fixed_reg_set); |
---|
926 | else |
---|
927 | COPY_HARD_REG_SET (used1, call_used_reg_set); |
---|
928 | |
---|
929 | /* Some registers should not be allocated in global-alloc. */ |
---|
930 | IOR_HARD_REG_SET (used1, no_global_alloc_regs); |
---|
931 | if (losers) |
---|
932 | IOR_HARD_REG_SET (used1, losers); |
---|
933 | |
---|
934 | IOR_COMPL_HARD_REG_SET (used1, reg_class_contents[(int) class]); |
---|
935 | COPY_HARD_REG_SET (used2, used1); |
---|
936 | |
---|
937 | IOR_HARD_REG_SET (used1, hard_reg_conflicts[allocno]); |
---|
938 | |
---|
939 | #ifdef CLASS_CANNOT_CHANGE_SIZE |
---|
940 | if (reg_changes_size[allocno_reg[allocno]]) |
---|
941 | IOR_HARD_REG_SET (used1, |
---|
942 | reg_class_contents[(int) CLASS_CANNOT_CHANGE_SIZE]); |
---|
943 | #endif |
---|
944 | |
---|
945 | /* Try each hard reg to see if it fits. Do this in two passes. |
---|
946 | In the first pass, skip registers that are preferred by some other pseudo |
---|
947 | to give it a better chance of getting one of those registers. Only if |
---|
948 | we can't get a register when excluding those do we take one of them. |
---|
949 | However, we never allocate a register for the first time in pass 0. */ |
---|
950 | |
---|
951 | COPY_HARD_REG_SET (used, used1); |
---|
952 | IOR_COMPL_HARD_REG_SET (used, regs_used_so_far); |
---|
953 | IOR_HARD_REG_SET (used, regs_someone_prefers[allocno]); |
---|
954 | |
---|
955 | best_reg = -1; |
---|
956 | for (i = FIRST_PSEUDO_REGISTER, pass = 0; |
---|
957 | pass <= 1 && i >= FIRST_PSEUDO_REGISTER; |
---|
958 | pass++) |
---|
959 | { |
---|
960 | if (pass == 1) |
---|
961 | COPY_HARD_REG_SET (used, used1); |
---|
962 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
---|
963 | { |
---|
964 | #ifdef REG_ALLOC_ORDER |
---|
965 | int regno = reg_alloc_order[i]; |
---|
966 | #else |
---|
967 | int regno = i; |
---|
968 | #endif |
---|
969 | if (! TEST_HARD_REG_BIT (used, regno) |
---|
970 | && HARD_REGNO_MODE_OK (regno, mode)) |
---|
971 | { |
---|
972 | register int j; |
---|
973 | register int lim = regno + HARD_REGNO_NREGS (regno, mode); |
---|
974 | for (j = regno + 1; |
---|
975 | (j < lim |
---|
976 | && ! TEST_HARD_REG_BIT (used, j)); |
---|
977 | j++); |
---|
978 | if (j == lim) |
---|
979 | { |
---|
980 | best_reg = regno; |
---|
981 | break; |
---|
982 | } |
---|
983 | #ifndef REG_ALLOC_ORDER |
---|
984 | i = j; /* Skip starting points we know will lose */ |
---|
985 | #endif |
---|
986 | } |
---|
987 | } |
---|
988 | } |
---|
989 | |
---|
990 | /* See if there is a preferred register with the same class as the register |
---|
991 | we allocated above. Making this restriction prevents register |
---|
992 | preferencing from creating worse register allocation. |
---|
993 | |
---|
994 | Remove from the preferred registers and conflicting registers. Note that |
---|
995 | additional conflicts may have been added after `prune_preferences' was |
---|
996 | called. |
---|
997 | |
---|
998 | First do this for those register with copy preferences, then all |
---|
999 | preferred registers. */ |
---|
1000 | |
---|
1001 | AND_COMPL_HARD_REG_SET (hard_reg_copy_preferences[allocno], used); |
---|
1002 | GO_IF_HARD_REG_SUBSET (hard_reg_copy_preferences[allocno], |
---|
1003 | reg_class_contents[(int) NO_REGS], no_copy_prefs); |
---|
1004 | |
---|
1005 | if (best_reg >= 0) |
---|
1006 | { |
---|
1007 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
---|
1008 | if (TEST_HARD_REG_BIT (hard_reg_copy_preferences[allocno], i) |
---|
1009 | && HARD_REGNO_MODE_OK (i, mode) |
---|
1010 | && (REGNO_REG_CLASS (i) == REGNO_REG_CLASS (best_reg) |
---|
1011 | || reg_class_subset_p (REGNO_REG_CLASS (i), |
---|
1012 | REGNO_REG_CLASS (best_reg)) |
---|
1013 | || reg_class_subset_p (REGNO_REG_CLASS (best_reg), |
---|
1014 | REGNO_REG_CLASS (i)))) |
---|
1015 | { |
---|
1016 | register int j; |
---|
1017 | register int lim = i + HARD_REGNO_NREGS (i, mode); |
---|
1018 | for (j = i + 1; |
---|
1019 | (j < lim |
---|
1020 | && ! TEST_HARD_REG_BIT (used, j) |
---|
1021 | && (REGNO_REG_CLASS (j) |
---|
1022 | == REGNO_REG_CLASS (best_reg + (j - i)) |
---|
1023 | || reg_class_subset_p (REGNO_REG_CLASS (j), |
---|
1024 | REGNO_REG_CLASS (best_reg + (j - i))) |
---|
1025 | || reg_class_subset_p (REGNO_REG_CLASS (best_reg + (j - i)), |
---|
1026 | REGNO_REG_CLASS (j)))); |
---|
1027 | j++); |
---|
1028 | if (j == lim) |
---|
1029 | { |
---|
1030 | best_reg = i; |
---|
1031 | goto no_prefs; |
---|
1032 | } |
---|
1033 | } |
---|
1034 | } |
---|
1035 | no_copy_prefs: |
---|
1036 | |
---|
1037 | AND_COMPL_HARD_REG_SET (hard_reg_preferences[allocno], used); |
---|
1038 | GO_IF_HARD_REG_SUBSET (hard_reg_preferences[allocno], |
---|
1039 | reg_class_contents[(int) NO_REGS], no_prefs); |
---|
1040 | |
---|
1041 | if (best_reg >= 0) |
---|
1042 | { |
---|
1043 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
---|
1044 | if (TEST_HARD_REG_BIT (hard_reg_preferences[allocno], i) |
---|
1045 | && HARD_REGNO_MODE_OK (i, mode) |
---|
1046 | && (REGNO_REG_CLASS (i) == REGNO_REG_CLASS (best_reg) |
---|
1047 | || reg_class_subset_p (REGNO_REG_CLASS (i), |
---|
1048 | REGNO_REG_CLASS (best_reg)) |
---|
1049 | || reg_class_subset_p (REGNO_REG_CLASS (best_reg), |
---|
1050 | REGNO_REG_CLASS (i)))) |
---|
1051 | { |
---|
1052 | register int j; |
---|
1053 | register int lim = i + HARD_REGNO_NREGS (i, mode); |
---|
1054 | for (j = i + 1; |
---|
1055 | (j < lim |
---|
1056 | && ! TEST_HARD_REG_BIT (used, j) |
---|
1057 | && (REGNO_REG_CLASS (j) |
---|
1058 | == REGNO_REG_CLASS (best_reg + (j - i)) |
---|
1059 | || reg_class_subset_p (REGNO_REG_CLASS (j), |
---|
1060 | REGNO_REG_CLASS (best_reg + (j - i))) |
---|
1061 | || reg_class_subset_p (REGNO_REG_CLASS (best_reg + (j - i)), |
---|
1062 | REGNO_REG_CLASS (j)))); |
---|
1063 | j++); |
---|
1064 | if (j == lim) |
---|
1065 | { |
---|
1066 | best_reg = i; |
---|
1067 | break; |
---|
1068 | } |
---|
1069 | } |
---|
1070 | } |
---|
1071 | no_prefs: |
---|
1072 | |
---|
1073 | /* If we haven't succeeded yet, try with caller-saves. |
---|
1074 | We need not check to see if the current function has nonlocal |
---|
1075 | labels because we don't put any pseudos that are live over calls in |
---|
1076 | registers in that case. */ |
---|
1077 | |
---|
1078 | if (flag_caller_saves && best_reg < 0) |
---|
1079 | { |
---|
1080 | /* Did not find a register. If it would be profitable to |
---|
1081 | allocate a call-clobbered register and save and restore it |
---|
1082 | around calls, do that. */ |
---|
1083 | if (! accept_call_clobbered |
---|
1084 | && allocno_calls_crossed[allocno] != 0 |
---|
1085 | && CALLER_SAVE_PROFITABLE (allocno_n_refs[allocno], |
---|
1086 | allocno_calls_crossed[allocno])) |
---|
1087 | { |
---|
1088 | find_reg (allocno, losers, alt_regs_p, 1, retrying); |
---|
1089 | if (reg_renumber[allocno_reg[allocno]] >= 0) |
---|
1090 | { |
---|
1091 | caller_save_needed = 1; |
---|
1092 | return; |
---|
1093 | } |
---|
1094 | } |
---|
1095 | } |
---|
1096 | |
---|
1097 | /* If we haven't succeeded yet, |
---|
1098 | see if some hard reg that conflicts with us |
---|
1099 | was utilized poorly by local-alloc. |
---|
1100 | If so, kick out the regs that were put there by local-alloc |
---|
1101 | so we can use it instead. */ |
---|
1102 | if (best_reg < 0 && !retrying |
---|
1103 | /* Let's not bother with multi-reg allocnos. */ |
---|
1104 | && allocno_size[allocno] == 1) |
---|
1105 | { |
---|
1106 | /* Count from the end, to find the least-used ones first. */ |
---|
1107 | for (i = FIRST_PSEUDO_REGISTER - 1; i >= 0; i--) |
---|
1108 | { |
---|
1109 | #ifdef REG_ALLOC_ORDER |
---|
1110 | int regno = reg_alloc_order[i]; |
---|
1111 | #else |
---|
1112 | int regno = i; |
---|
1113 | #endif |
---|
1114 | |
---|
1115 | if (local_reg_n_refs[regno] != 0 |
---|
1116 | /* Don't use a reg no good for this pseudo. */ |
---|
1117 | && ! TEST_HARD_REG_BIT (used2, regno) |
---|
1118 | && HARD_REGNO_MODE_OK (regno, mode) |
---|
1119 | #ifdef CLASS_CANNOT_CHANGE_SIZE |
---|
1120 | && ! (reg_changes_size[allocno_reg[allocno]] |
---|
1121 | && (TEST_HARD_REG_BIT |
---|
1122 | (reg_class_contents[(int) CLASS_CANNOT_CHANGE_SIZE], |
---|
1123 | regno))) |
---|
1124 | #endif |
---|
1125 | ) |
---|
1126 | { |
---|
1127 | /* We explicitly evaluate the divide results into temporary |
---|
1128 | variables so as to avoid excess precision problems that occur |
---|
1129 | on a i386-unknown-sysv4.2 (unixware) host. */ |
---|
1130 | |
---|
1131 | double tmp1 = ((double) local_reg_n_refs[regno] |
---|
1132 | / local_reg_live_length[regno]); |
---|
1133 | double tmp2 = ((double) allocno_n_refs[allocno] |
---|
1134 | / allocno_live_length[allocno]); |
---|
1135 | |
---|
1136 | if (tmp1 < tmp2) |
---|
1137 | { |
---|
1138 | /* Hard reg REGNO was used less in total by local regs |
---|
1139 | than it would be used by this one allocno! */ |
---|
1140 | int k; |
---|
1141 | for (k = 0; k < max_regno; k++) |
---|
1142 | if (reg_renumber[k] >= 0) |
---|
1143 | { |
---|
1144 | int r = reg_renumber[k]; |
---|
1145 | int endregno |
---|
1146 | = r + HARD_REGNO_NREGS (r, PSEUDO_REGNO_MODE (k)); |
---|
1147 | |
---|
1148 | if (regno >= r && regno < endregno) |
---|
1149 | reg_renumber[k] = -1; |
---|
1150 | } |
---|
1151 | |
---|
1152 | best_reg = regno; |
---|
1153 | break; |
---|
1154 | } |
---|
1155 | } |
---|
1156 | } |
---|
1157 | } |
---|
1158 | |
---|
1159 | /* Did we find a register? */ |
---|
1160 | |
---|
1161 | if (best_reg >= 0) |
---|
1162 | { |
---|
1163 | register int lim, j; |
---|
1164 | HARD_REG_SET this_reg; |
---|
1165 | |
---|
1166 | /* Yes. Record it as the hard register of this pseudo-reg. */ |
---|
1167 | reg_renumber[allocno_reg[allocno]] = best_reg; |
---|
1168 | /* Also of any pseudo-regs that share with it. */ |
---|
1169 | if (reg_may_share[allocno_reg[allocno]]) |
---|
1170 | for (j = FIRST_PSEUDO_REGISTER; j < max_regno; j++) |
---|
1171 | if (reg_allocno[j] == allocno) |
---|
1172 | reg_renumber[j] = best_reg; |
---|
1173 | |
---|
1174 | /* Make a set of the hard regs being allocated. */ |
---|
1175 | CLEAR_HARD_REG_SET (this_reg); |
---|
1176 | lim = best_reg + HARD_REGNO_NREGS (best_reg, mode); |
---|
1177 | for (j = best_reg; j < lim; j++) |
---|
1178 | { |
---|
1179 | SET_HARD_REG_BIT (this_reg, j); |
---|
1180 | SET_HARD_REG_BIT (regs_used_so_far, j); |
---|
1181 | /* This is no longer a reg used just by local regs. */ |
---|
1182 | local_reg_n_refs[j] = 0; |
---|
1183 | } |
---|
1184 | /* For each other pseudo-reg conflicting with this one, |
---|
1185 | mark it as conflicting with the hard regs this one occupies. */ |
---|
1186 | lim = allocno; |
---|
1187 | for (j = 0; j < max_allocno; j++) |
---|
1188 | if (CONFLICTP (lim, j) || CONFLICTP (j, lim)) |
---|
1189 | { |
---|
1190 | IOR_HARD_REG_SET (hard_reg_conflicts[j], this_reg); |
---|
1191 | } |
---|
1192 | } |
---|
1193 | } |
---|
1194 | |
---|
1195 | /* Called from `reload' to look for a hard reg to put pseudo reg REGNO in. |
---|
1196 | Perhaps it had previously seemed not worth a hard reg, |
---|
1197 | or perhaps its old hard reg has been commandeered for reloads. |
---|
1198 | FORBIDDEN_REGS indicates certain hard regs that may not be used, even if |
---|
1199 | they do not appear to be allocated. |
---|
1200 | If FORBIDDEN_REGS is zero, no regs are forbidden. */ |
---|
1201 | |
---|
1202 | void |
---|
1203 | retry_global_alloc (regno, forbidden_regs) |
---|
1204 | int regno; |
---|
1205 | HARD_REG_SET forbidden_regs; |
---|
1206 | { |
---|
1207 | int allocno = reg_allocno[regno]; |
---|
1208 | if (allocno >= 0) |
---|
1209 | { |
---|
1210 | /* If we have more than one register class, |
---|
1211 | first try allocating in the class that is cheapest |
---|
1212 | for this pseudo-reg. If that fails, try any reg. */ |
---|
1213 | if (N_REG_CLASSES > 1) |
---|
1214 | find_reg (allocno, forbidden_regs, 0, 0, 1); |
---|
1215 | if (reg_renumber[regno] < 0 |
---|
1216 | && reg_alternate_class (regno) != NO_REGS) |
---|
1217 | find_reg (allocno, forbidden_regs, 1, 0, 1); |
---|
1218 | |
---|
1219 | /* If we found a register, modify the RTL for the register to |
---|
1220 | show the hard register, and mark that register live. */ |
---|
1221 | if (reg_renumber[regno] >= 0) |
---|
1222 | { |
---|
1223 | REGNO (regno_reg_rtx[regno]) = reg_renumber[regno]; |
---|
1224 | mark_home_live (regno); |
---|
1225 | } |
---|
1226 | } |
---|
1227 | } |
---|
1228 | |
---|
1229 | /* Record a conflict between register REGNO |
---|
1230 | and everything currently live. |
---|
1231 | REGNO must not be a pseudo reg that was allocated |
---|
1232 | by local_alloc; such numbers must be translated through |
---|
1233 | reg_renumber before calling here. */ |
---|
1234 | |
---|
1235 | static void |
---|
1236 | record_one_conflict (regno) |
---|
1237 | int regno; |
---|
1238 | { |
---|
1239 | register int j; |
---|
1240 | |
---|
1241 | if (regno < FIRST_PSEUDO_REGISTER) |
---|
1242 | /* When a hard register becomes live, |
---|
1243 | record conflicts with live pseudo regs. */ |
---|
1244 | for (j = 0; j < max_allocno; j++) |
---|
1245 | { |
---|
1246 | if (ALLOCNO_LIVE_P (j)) |
---|
1247 | SET_HARD_REG_BIT (hard_reg_conflicts[j], regno); |
---|
1248 | } |
---|
1249 | else |
---|
1250 | /* When a pseudo-register becomes live, |
---|
1251 | record conflicts first with hard regs, |
---|
1252 | then with other pseudo regs. */ |
---|
1253 | { |
---|
1254 | register int ialloc = reg_allocno[regno]; |
---|
1255 | register int ialloc_prod = ialloc * allocno_row_words; |
---|
1256 | IOR_HARD_REG_SET (hard_reg_conflicts[ialloc], hard_regs_live); |
---|
1257 | for (j = allocno_row_words - 1; j >= 0; j--) |
---|
1258 | { |
---|
1259 | #if 0 |
---|
1260 | int k; |
---|
1261 | for (k = 0; k < n_no_conflict_pairs; k++) |
---|
1262 | if (! ((j == no_conflict_pairs[k].allocno1 |
---|
1263 | && ialloc == no_conflict_pairs[k].allocno2) |
---|
1264 | || |
---|
1265 | (j == no_conflict_pairs[k].allocno2 |
---|
1266 | && ialloc == no_conflict_pairs[k].allocno1))) |
---|
1267 | #endif /* 0 */ |
---|
1268 | conflicts[ialloc_prod + j] |= allocnos_live[j]; |
---|
1269 | } |
---|
1270 | } |
---|
1271 | } |
---|
1272 | |
---|
1273 | /* Record all allocnos currently live as conflicting |
---|
1274 | with each other and with all hard regs currently live. |
---|
1275 | ALLOCNO_VEC is a vector of LEN allocnos, all allocnos that |
---|
1276 | are currently live. Their bits are also flagged in allocnos_live. */ |
---|
1277 | |
---|
1278 | static void |
---|
1279 | record_conflicts (allocno_vec, len) |
---|
1280 | register short *allocno_vec; |
---|
1281 | register int len; |
---|
1282 | { |
---|
1283 | register int allocno; |
---|
1284 | register int j; |
---|
1285 | register int ialloc_prod; |
---|
1286 | |
---|
1287 | while (--len >= 0) |
---|
1288 | { |
---|
1289 | allocno = allocno_vec[len]; |
---|
1290 | ialloc_prod = allocno * allocno_row_words; |
---|
1291 | IOR_HARD_REG_SET (hard_reg_conflicts[allocno], hard_regs_live); |
---|
1292 | for (j = allocno_row_words - 1; j >= 0; j--) |
---|
1293 | conflicts[ialloc_prod + j] |= allocnos_live[j]; |
---|
1294 | } |
---|
1295 | } |
---|
1296 | |
---|
1297 | /* Handle the case where REG is set by the insn being scanned, |
---|
1298 | during the forward scan to accumulate conflicts. |
---|
1299 | Store a 1 in regs_live or allocnos_live for this register, record how many |
---|
1300 | consecutive hardware registers it actually needs, |
---|
1301 | and record a conflict with all other registers already live. |
---|
1302 | |
---|
1303 | Note that even if REG does not remain alive after this insn, |
---|
1304 | we must mark it here as live, to ensure a conflict between |
---|
1305 | REG and any other regs set in this insn that really do live. |
---|
1306 | This is because those other regs could be considered after this. |
---|
1307 | |
---|
1308 | REG might actually be something other than a register; |
---|
1309 | if so, we do nothing. |
---|
1310 | |
---|
1311 | SETTER is 0 if this register was modified by an auto-increment (i.e., |
---|
1312 | a REG_INC note was found for it). |
---|
1313 | |
---|
1314 | CLOBBERs are processed here by calling mark_reg_clobber. */ |
---|
1315 | |
---|
1316 | static void |
---|
1317 | mark_reg_store (orig_reg, setter) |
---|
1318 | rtx orig_reg, setter; |
---|
1319 | { |
---|
1320 | register int regno; |
---|
1321 | register rtx reg = orig_reg; |
---|
1322 | |
---|
1323 | /* WORD is which word of a multi-register group is being stored. |
---|
1324 | For the case where the store is actually into a SUBREG of REG. |
---|
1325 | Except we don't use it; I believe the entire REG needs to be |
---|
1326 | made live. */ |
---|
1327 | int word = 0; |
---|
1328 | |
---|
1329 | if (GET_CODE (reg) == SUBREG) |
---|
1330 | { |
---|
1331 | word = SUBREG_WORD (reg); |
---|
1332 | reg = SUBREG_REG (reg); |
---|
1333 | } |
---|
1334 | |
---|
1335 | if (GET_CODE (reg) != REG) |
---|
1336 | return; |
---|
1337 | |
---|
1338 | if (setter && GET_CODE (setter) == CLOBBER) |
---|
1339 | { |
---|
1340 | /* A clobber of a register should be processed here too. */ |
---|
1341 | mark_reg_clobber (orig_reg, setter); |
---|
1342 | return; |
---|
1343 | } |
---|
1344 | |
---|
1345 | regs_set[n_regs_set++] = reg; |
---|
1346 | |
---|
1347 | if (setter) |
---|
1348 | set_preference (reg, SET_SRC (setter)); |
---|
1349 | |
---|
1350 | regno = REGNO (reg); |
---|
1351 | |
---|
1352 | if (reg_renumber[regno] >= 0) |
---|
1353 | regno = reg_renumber[regno] /* + word */; |
---|
1354 | |
---|
1355 | /* Either this is one of the max_allocno pseudo regs not allocated, |
---|
1356 | or it is or has a hardware reg. First handle the pseudo-regs. */ |
---|
1357 | if (regno >= FIRST_PSEUDO_REGISTER) |
---|
1358 | { |
---|
1359 | if (reg_allocno[regno] >= 0) |
---|
1360 | { |
---|
1361 | SET_ALLOCNO_LIVE (reg_allocno[regno]); |
---|
1362 | record_one_conflict (regno); |
---|
1363 | } |
---|
1364 | } |
---|
1365 | /* Handle hardware regs (and pseudos allocated to hard regs). */ |
---|
1366 | else if (! fixed_regs[regno]) |
---|
1367 | { |
---|
1368 | register int last = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)); |
---|
1369 | while (regno < last) |
---|
1370 | { |
---|
1371 | record_one_conflict (regno); |
---|
1372 | SET_HARD_REG_BIT (hard_regs_live, regno); |
---|
1373 | regno++; |
---|
1374 | } |
---|
1375 | } |
---|
1376 | } |
---|
1377 | |
---|
1378 | /* Like mark_reg_set except notice just CLOBBERs; ignore SETs. */ |
---|
1379 | |
---|
1380 | static void |
---|
1381 | mark_reg_clobber (reg, setter) |
---|
1382 | rtx reg, setter; |
---|
1383 | { |
---|
1384 | register int regno; |
---|
1385 | |
---|
1386 | /* WORD is which word of a multi-register group is being stored. |
---|
1387 | For the case where the store is actually into a SUBREG of REG. |
---|
1388 | Except we don't use it; I believe the entire REG needs to be |
---|
1389 | made live. */ |
---|
1390 | int word = 0; |
---|
1391 | |
---|
1392 | if (GET_CODE (setter) != CLOBBER) |
---|
1393 | return; |
---|
1394 | |
---|
1395 | if (GET_CODE (reg) == SUBREG) |
---|
1396 | { |
---|
1397 | word = SUBREG_WORD (reg); |
---|
1398 | reg = SUBREG_REG (reg); |
---|
1399 | } |
---|
1400 | |
---|
1401 | if (GET_CODE (reg) != REG) |
---|
1402 | return; |
---|
1403 | |
---|
1404 | regs_set[n_regs_set++] = reg; |
---|
1405 | |
---|
1406 | regno = REGNO (reg); |
---|
1407 | |
---|
1408 | if (reg_renumber[regno] >= 0) |
---|
1409 | regno = reg_renumber[regno] /* + word */; |
---|
1410 | |
---|
1411 | /* Either this is one of the max_allocno pseudo regs not allocated, |
---|
1412 | or it is or has a hardware reg. First handle the pseudo-regs. */ |
---|
1413 | if (regno >= FIRST_PSEUDO_REGISTER) |
---|
1414 | { |
---|
1415 | if (reg_allocno[regno] >= 0) |
---|
1416 | { |
---|
1417 | SET_ALLOCNO_LIVE (reg_allocno[regno]); |
---|
1418 | record_one_conflict (regno); |
---|
1419 | } |
---|
1420 | } |
---|
1421 | /* Handle hardware regs (and pseudos allocated to hard regs). */ |
---|
1422 | else if (! fixed_regs[regno]) |
---|
1423 | { |
---|
1424 | register int last = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)); |
---|
1425 | while (regno < last) |
---|
1426 | { |
---|
1427 | record_one_conflict (regno); |
---|
1428 | SET_HARD_REG_BIT (hard_regs_live, regno); |
---|
1429 | regno++; |
---|
1430 | } |
---|
1431 | } |
---|
1432 | } |
---|
1433 | |
---|
1434 | /* Record that REG has conflicts with all the regs currently live. |
---|
1435 | Do not mark REG itself as live. */ |
---|
1436 | |
---|
1437 | static void |
---|
1438 | mark_reg_conflicts (reg) |
---|
1439 | rtx reg; |
---|
1440 | { |
---|
1441 | register int regno; |
---|
1442 | |
---|
1443 | if (GET_CODE (reg) == SUBREG) |
---|
1444 | reg = SUBREG_REG (reg); |
---|
1445 | |
---|
1446 | if (GET_CODE (reg) != REG) |
---|
1447 | return; |
---|
1448 | |
---|
1449 | regno = REGNO (reg); |
---|
1450 | |
---|
1451 | if (reg_renumber[regno] >= 0) |
---|
1452 | regno = reg_renumber[regno]; |
---|
1453 | |
---|
1454 | /* Either this is one of the max_allocno pseudo regs not allocated, |
---|
1455 | or it is or has a hardware reg. First handle the pseudo-regs. */ |
---|
1456 | if (regno >= FIRST_PSEUDO_REGISTER) |
---|
1457 | { |
---|
1458 | if (reg_allocno[regno] >= 0) |
---|
1459 | record_one_conflict (regno); |
---|
1460 | } |
---|
1461 | /* Handle hardware regs (and pseudos allocated to hard regs). */ |
---|
1462 | else if (! fixed_regs[regno]) |
---|
1463 | { |
---|
1464 | register int last = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)); |
---|
1465 | while (regno < last) |
---|
1466 | { |
---|
1467 | record_one_conflict (regno); |
---|
1468 | regno++; |
---|
1469 | } |
---|
1470 | } |
---|
1471 | } |
---|
1472 | |
---|
1473 | /* Mark REG as being dead (following the insn being scanned now). |
---|
1474 | Store a 0 in regs_live or allocnos_live for this register. */ |
---|
1475 | |
---|
1476 | static void |
---|
1477 | mark_reg_death (reg) |
---|
1478 | rtx reg; |
---|
1479 | { |
---|
1480 | register int regno = REGNO (reg); |
---|
1481 | |
---|
1482 | /* For pseudo reg, see if it has been assigned a hardware reg. */ |
---|
1483 | if (reg_renumber[regno] >= 0) |
---|
1484 | regno = reg_renumber[regno]; |
---|
1485 | |
---|
1486 | /* Either this is one of the max_allocno pseudo regs not allocated, |
---|
1487 | or it is a hardware reg. First handle the pseudo-regs. */ |
---|
1488 | if (regno >= FIRST_PSEUDO_REGISTER) |
---|
1489 | { |
---|
1490 | if (reg_allocno[regno] >= 0) |
---|
1491 | CLEAR_ALLOCNO_LIVE (reg_allocno[regno]); |
---|
1492 | } |
---|
1493 | /* Handle hardware regs (and pseudos allocated to hard regs). */ |
---|
1494 | else if (! fixed_regs[regno]) |
---|
1495 | { |
---|
1496 | /* Pseudo regs already assigned hardware regs are treated |
---|
1497 | almost the same as explicit hardware regs. */ |
---|
1498 | register int last = regno + HARD_REGNO_NREGS (regno, GET_MODE (reg)); |
---|
1499 | while (regno < last) |
---|
1500 | { |
---|
1501 | CLEAR_HARD_REG_BIT (hard_regs_live, regno); |
---|
1502 | regno++; |
---|
1503 | } |
---|
1504 | } |
---|
1505 | } |
---|
1506 | |
---|
1507 | /* Mark hard reg REGNO as currently live, assuming machine mode MODE |
---|
1508 | for the value stored in it. MODE determines how many consecutive |
---|
1509 | registers are actually in use. Do not record conflicts; |
---|
1510 | it is assumed that the caller will do that. */ |
---|
1511 | |
---|
1512 | static void |
---|
1513 | mark_reg_live_nc (regno, mode) |
---|
1514 | register int regno; |
---|
1515 | enum machine_mode mode; |
---|
1516 | { |
---|
1517 | register int last = regno + HARD_REGNO_NREGS (regno, mode); |
---|
1518 | while (regno < last) |
---|
1519 | { |
---|
1520 | SET_HARD_REG_BIT (hard_regs_live, regno); |
---|
1521 | regno++; |
---|
1522 | } |
---|
1523 | } |
---|
1524 | |
---|
1525 | /* Try to set a preference for an allocno to a hard register. |
---|
1526 | We are passed DEST and SRC which are the operands of a SET. It is known |
---|
1527 | that SRC is a register. If SRC or the first operand of SRC is a register, |
---|
1528 | try to set a preference. If one of the two is a hard register and the other |
---|
1529 | is a pseudo-register, mark the preference. |
---|
1530 | |
---|
1531 | Note that we are not as aggressive as local-alloc in trying to tie a |
---|
1532 | pseudo-register to a hard register. */ |
---|
1533 | |
---|
1534 | static void |
---|
1535 | set_preference (dest, src) |
---|
1536 | rtx dest, src; |
---|
1537 | { |
---|
1538 | int src_regno, dest_regno; |
---|
1539 | /* Amount to add to the hard regno for SRC, or subtract from that for DEST, |
---|
1540 | to compensate for subregs in SRC or DEST. */ |
---|
1541 | int offset = 0; |
---|
1542 | int i; |
---|
1543 | int copy = 1; |
---|
1544 | |
---|
1545 | if (GET_RTX_FORMAT (GET_CODE (src))[0] == 'e') |
---|
1546 | src = XEXP (src, 0), copy = 0; |
---|
1547 | |
---|
1548 | /* Get the reg number for both SRC and DEST. |
---|
1549 | If neither is a reg, give up. */ |
---|
1550 | |
---|
1551 | if (GET_CODE (src) == REG) |
---|
1552 | src_regno = REGNO (src); |
---|
1553 | else if (GET_CODE (src) == SUBREG && GET_CODE (SUBREG_REG (src)) == REG) |
---|
1554 | { |
---|
1555 | src_regno = REGNO (SUBREG_REG (src)); |
---|
1556 | offset += SUBREG_WORD (src); |
---|
1557 | } |
---|
1558 | else |
---|
1559 | return; |
---|
1560 | |
---|
1561 | if (GET_CODE (dest) == REG) |
---|
1562 | dest_regno = REGNO (dest); |
---|
1563 | else if (GET_CODE (dest) == SUBREG && GET_CODE (SUBREG_REG (dest)) == REG) |
---|
1564 | { |
---|
1565 | dest_regno = REGNO (SUBREG_REG (dest)); |
---|
1566 | offset -= SUBREG_WORD (dest); |
---|
1567 | } |
---|
1568 | else |
---|
1569 | return; |
---|
1570 | |
---|
1571 | /* Convert either or both to hard reg numbers. */ |
---|
1572 | |
---|
1573 | if (reg_renumber[src_regno] >= 0) |
---|
1574 | src_regno = reg_renumber[src_regno]; |
---|
1575 | |
---|
1576 | if (reg_renumber[dest_regno] >= 0) |
---|
1577 | dest_regno = reg_renumber[dest_regno]; |
---|
1578 | |
---|
1579 | /* Now if one is a hard reg and the other is a global pseudo |
---|
1580 | then give the other a preference. */ |
---|
1581 | |
---|
1582 | if (dest_regno < FIRST_PSEUDO_REGISTER && src_regno >= FIRST_PSEUDO_REGISTER |
---|
1583 | && reg_allocno[src_regno] >= 0) |
---|
1584 | { |
---|
1585 | dest_regno -= offset; |
---|
1586 | if (dest_regno >= 0 && dest_regno < FIRST_PSEUDO_REGISTER) |
---|
1587 | { |
---|
1588 | if (copy) |
---|
1589 | SET_REGBIT (hard_reg_copy_preferences, |
---|
1590 | reg_allocno[src_regno], dest_regno); |
---|
1591 | |
---|
1592 | SET_REGBIT (hard_reg_preferences, |
---|
1593 | reg_allocno[src_regno], dest_regno); |
---|
1594 | for (i = dest_regno; |
---|
1595 | i < dest_regno + HARD_REGNO_NREGS (dest_regno, GET_MODE (dest)); |
---|
1596 | i++) |
---|
1597 | SET_REGBIT (hard_reg_full_preferences, reg_allocno[src_regno], i); |
---|
1598 | } |
---|
1599 | } |
---|
1600 | |
---|
1601 | if (src_regno < FIRST_PSEUDO_REGISTER && dest_regno >= FIRST_PSEUDO_REGISTER |
---|
1602 | && reg_allocno[dest_regno] >= 0) |
---|
1603 | { |
---|
1604 | src_regno += offset; |
---|
1605 | if (src_regno >= 0 && src_regno < FIRST_PSEUDO_REGISTER) |
---|
1606 | { |
---|
1607 | if (copy) |
---|
1608 | SET_REGBIT (hard_reg_copy_preferences, |
---|
1609 | reg_allocno[dest_regno], src_regno); |
---|
1610 | |
---|
1611 | SET_REGBIT (hard_reg_preferences, |
---|
1612 | reg_allocno[dest_regno], src_regno); |
---|
1613 | for (i = src_regno; |
---|
1614 | i < src_regno + HARD_REGNO_NREGS (src_regno, GET_MODE (src)); |
---|
1615 | i++) |
---|
1616 | SET_REGBIT (hard_reg_full_preferences, reg_allocno[dest_regno], i); |
---|
1617 | } |
---|
1618 | } |
---|
1619 | } |
---|
1620 | |
---|
1621 | /* Indicate that hard register number FROM was eliminated and replaced with |
---|
1622 | an offset from hard register number TO. The status of hard registers live |
---|
1623 | at the start of a basic block is updated by replacing a use of FROM with |
---|
1624 | a use of TO. */ |
---|
1625 | |
---|
1626 | void |
---|
1627 | mark_elimination (from, to) |
---|
1628 | int from, to; |
---|
1629 | { |
---|
1630 | int i; |
---|
1631 | |
---|
1632 | for (i = 0; i < n_basic_blocks; i++) |
---|
1633 | if ((basic_block_live_at_start[i][from / REGSET_ELT_BITS] |
---|
1634 | & ((REGSET_ELT_TYPE) 1 << (from % REGSET_ELT_BITS))) != 0) |
---|
1635 | { |
---|
1636 | basic_block_live_at_start[i][from / REGSET_ELT_BITS] |
---|
1637 | &= ~ ((REGSET_ELT_TYPE) 1 << (from % REGSET_ELT_BITS)); |
---|
1638 | basic_block_live_at_start[i][to / REGSET_ELT_BITS] |
---|
1639 | |= ((REGSET_ELT_TYPE) 1 << (to % REGSET_ELT_BITS)); |
---|
1640 | } |
---|
1641 | } |
---|
1642 | |
---|
1643 | /* Print debugging trace information if -greg switch is given, |
---|
1644 | showing the information on which the allocation decisions are based. */ |
---|
1645 | |
---|
1646 | static void |
---|
1647 | dump_conflicts (file) |
---|
1648 | FILE *file; |
---|
1649 | { |
---|
1650 | register int i; |
---|
1651 | register int has_preferences; |
---|
1652 | fprintf (file, ";; %d regs to allocate:", max_allocno); |
---|
1653 | for (i = 0; i < max_allocno; i++) |
---|
1654 | { |
---|
1655 | int j; |
---|
1656 | fprintf (file, " %d", allocno_reg[allocno_order[i]]); |
---|
1657 | for (j = 0; j < max_regno; j++) |
---|
1658 | if (reg_allocno[j] == allocno_order[i] |
---|
1659 | && j != allocno_reg[allocno_order[i]]) |
---|
1660 | fprintf (file, "+%d", j); |
---|
1661 | if (allocno_size[allocno_order[i]] != 1) |
---|
1662 | fprintf (file, " (%d)", allocno_size[allocno_order[i]]); |
---|
1663 | } |
---|
1664 | fprintf (file, "\n"); |
---|
1665 | |
---|
1666 | for (i = 0; i < max_allocno; i++) |
---|
1667 | { |
---|
1668 | register int j; |
---|
1669 | fprintf (file, ";; %d conflicts:", allocno_reg[i]); |
---|
1670 | for (j = 0; j < max_allocno; j++) |
---|
1671 | if (CONFLICTP (i, j) || CONFLICTP (j, i)) |
---|
1672 | fprintf (file, " %d", allocno_reg[j]); |
---|
1673 | for (j = 0; j < FIRST_PSEUDO_REGISTER; j++) |
---|
1674 | if (TEST_HARD_REG_BIT (hard_reg_conflicts[i], j)) |
---|
1675 | fprintf (file, " %d", j); |
---|
1676 | fprintf (file, "\n"); |
---|
1677 | |
---|
1678 | has_preferences = 0; |
---|
1679 | for (j = 0; j < FIRST_PSEUDO_REGISTER; j++) |
---|
1680 | if (TEST_HARD_REG_BIT (hard_reg_preferences[i], j)) |
---|
1681 | has_preferences = 1; |
---|
1682 | |
---|
1683 | if (! has_preferences) |
---|
1684 | continue; |
---|
1685 | fprintf (file, ";; %d preferences:", allocno_reg[i]); |
---|
1686 | for (j = 0; j < FIRST_PSEUDO_REGISTER; j++) |
---|
1687 | if (TEST_HARD_REG_BIT (hard_reg_preferences[i], j)) |
---|
1688 | fprintf (file, " %d", j); |
---|
1689 | fprintf (file, "\n"); |
---|
1690 | } |
---|
1691 | fprintf (file, "\n"); |
---|
1692 | } |
---|
1693 | |
---|
1694 | void |
---|
1695 | dump_global_regs (file) |
---|
1696 | FILE *file; |
---|
1697 | { |
---|
1698 | register int i, j; |
---|
1699 | |
---|
1700 | fprintf (file, ";; Register dispositions:\n"); |
---|
1701 | for (i = FIRST_PSEUDO_REGISTER, j = 0; i < max_regno; i++) |
---|
1702 | if (reg_renumber[i] >= 0) |
---|
1703 | { |
---|
1704 | fprintf (file, "%d in %d ", i, reg_renumber[i]); |
---|
1705 | if (++j % 6 == 0) |
---|
1706 | fprintf (file, "\n"); |
---|
1707 | } |
---|
1708 | |
---|
1709 | fprintf (file, "\n\n;; Hard regs used: "); |
---|
1710 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
---|
1711 | if (regs_ever_live[i]) |
---|
1712 | fprintf (file, " %d", i); |
---|
1713 | fprintf (file, "\n\n"); |
---|
1714 | } |
---|