1 | /* Define per-register tables for data flow info and register allocation. |
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2 | Copyright (C) 1987, 1993, 1994, 1995, 1997 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 | |
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23 | #define REG_BYTES(R) mode_size[(int) GET_MODE (R)] |
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24 | |
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25 | /* Get the number of consecutive hard regs required to hold the REG rtx R. |
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26 | When something may be an explicit hard reg, REG_SIZE is the only |
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27 | valid way to get this value. You cannot get it from the regno. */ |
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28 | |
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29 | #define REG_SIZE(R) \ |
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30 | ((mode_size[(int) GET_MODE (R)] + UNITS_PER_WORD - 1) / UNITS_PER_WORD) |
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31 | |
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32 | #ifndef SMALL_REGISTER_CLASSES |
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33 | #define SMALL_REGISTER_CLASSES 0 |
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34 | #endif |
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35 | |
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36 | /* Maximum register number used in this function, plus one. */ |
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37 | |
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38 | extern int max_regno; |
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39 | |
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40 | /* Maximum number of SCRATCH rtx's in each block of this function. */ |
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41 | |
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42 | extern int max_scratch; |
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43 | |
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44 | /* Register information indexed by register number */ |
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45 | typedef struct reg_info_def { |
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46 | /* fields set by reg_scan */ |
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47 | int first_uid; /* UID of first insn to use (REG n) */ |
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48 | int last_uid; /* UID of last insn to use (REG n) */ |
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49 | int last_note_uid; /* UID of last note to use (REG n) */ |
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50 | |
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51 | /* fields set by both reg_scan and flow_analysis */ |
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52 | int sets; /* # of times (REG n) is set */ |
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53 | |
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54 | /* fields set by flow_analysis */ |
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55 | int refs; /* # of times (REG n) is used or set */ |
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56 | int deaths; /* # of times (REG n) dies */ |
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57 | int live_length; /* # of instructions (REG n) is live */ |
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58 | int calls_crossed; /* # of calls (REG n) is live across */ |
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59 | int basic_block; /* # of basic blocks (REG n) is used in */ |
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60 | char changes_size; /* whether (SUBREG (REG n)) changes size */ |
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61 | } reg_info; |
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62 | |
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63 | extern reg_info *reg_n_info; |
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64 | |
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65 | /* Indexed by n, gives number of times (REG n) is used or set. |
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66 | References within loops may be counted more times. */ |
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67 | |
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68 | #define REG_N_REFS(N) (reg_n_info[(N)].refs) |
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69 | |
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70 | /* Indexed by n, gives number of times (REG n) is set. |
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71 | ??? both regscan and flow allocate space for this. We should settle |
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72 | on just copy. */ |
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73 | |
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74 | #define REG_N_SETS(N) (reg_n_info[(N)].sets) |
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75 | |
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76 | /* Indexed by N, gives number of insns in which register N dies. |
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77 | Note that if register N is live around loops, it can die |
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78 | in transitions between basic blocks, and that is not counted here. |
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79 | So this is only a reliable indicator of how many regions of life there are |
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80 | for registers that are contained in one basic block. */ |
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81 | |
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82 | #define REG_N_DEATHS(N) (reg_n_info[(N)].deaths) |
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83 | |
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84 | /* Indexed by N; says whether a pseudo register N was ever used |
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85 | within a SUBREG that changes the size of the reg. Some machines prohibit |
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86 | such objects to be in certain (usually floating-point) registers. */ |
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87 | |
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88 | #define REG_CHANGES_SIZE(N) (reg_n_info[(N)].changes_size) |
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89 | |
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90 | /* Get the number of consecutive words required to hold pseudo-reg N. */ |
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91 | |
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92 | #define PSEUDO_REGNO_SIZE(N) \ |
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93 | ((GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) + UNITS_PER_WORD - 1) \ |
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94 | / UNITS_PER_WORD) |
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95 | |
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96 | /* Get the number of bytes required to hold pseudo-reg N. */ |
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97 | |
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98 | #define PSEUDO_REGNO_BYTES(N) \ |
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99 | GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) |
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100 | |
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101 | /* Get the machine mode of pseudo-reg N. */ |
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102 | |
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103 | #define PSEUDO_REGNO_MODE(N) GET_MODE (regno_reg_rtx[N]) |
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104 | |
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105 | /* Indexed by N, gives number of CALL_INSNS across which (REG n) is live. */ |
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106 | |
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107 | #define REG_N_CALLS_CROSSED(N) (reg_n_info[(N)].calls_crossed) |
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108 | |
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109 | /* Total number of instructions at which (REG n) is live. |
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110 | The larger this is, the less priority (REG n) gets for |
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111 | allocation in a hard register (in global-alloc). |
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112 | This is set in flow.c and remains valid for the rest of the compilation |
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113 | of the function; it is used to control register allocation. |
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114 | |
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115 | local-alloc.c may alter this number to change the priority. |
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116 | |
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117 | Negative values are special. |
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118 | -1 is used to mark a pseudo reg which has a constant or memory equivalent |
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119 | and is used infrequently enough that it should not get a hard register. |
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120 | -2 is used to mark a pseudo reg for a parameter, when a frame pointer |
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121 | is not required. global.c makes an allocno for this but does |
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122 | not try to assign a hard register to it. */ |
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123 | |
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124 | #define REG_LIVE_LENGTH(N) (reg_n_info[(N)].live_length) |
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125 | |
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126 | /* Vector of substitutions of register numbers, |
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127 | used to map pseudo regs into hardware regs. |
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128 | |
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129 | This can't be folded into reg_n_info without changing all of the |
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130 | machine dependent directories, since the reload functions |
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131 | in the machine dependent files access it. */ |
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132 | |
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133 | extern short *reg_renumber; |
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134 | |
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135 | /* Vector indexed by hardware reg |
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136 | saying whether that reg is ever used. */ |
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137 | |
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138 | extern char regs_ever_live[FIRST_PSEUDO_REGISTER]; |
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139 | |
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140 | /* Vector indexed by hardware reg giving its name. */ |
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141 | |
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142 | extern char *reg_names[FIRST_PSEUDO_REGISTER]; |
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143 | |
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144 | /* For each hard register, the widest mode object that it can contain. |
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145 | This will be a MODE_INT mode if the register can hold integers. Otherwise |
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146 | it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the |
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147 | register. */ |
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148 | |
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149 | extern enum machine_mode reg_raw_mode[FIRST_PSEUDO_REGISTER]; |
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150 | |
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151 | /* Vector indexed by regno; gives uid of first insn using that reg. |
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152 | This is computed by reg_scan for use by cse and loop. |
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153 | It is sometimes adjusted for subsequent changes during loop, |
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154 | but not adjusted by cse even if cse invalidates it. */ |
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155 | |
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156 | #define REGNO_FIRST_UID(N) (reg_n_info[(N)].first_uid) |
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157 | |
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158 | /* Vector indexed by regno; gives uid of last insn using that reg. |
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159 | This is computed by reg_scan for use by cse and loop. |
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160 | It is sometimes adjusted for subsequent changes during loop, |
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161 | but not adjusted by cse even if cse invalidates it. |
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162 | This is harmless since cse won't scan through a loop end. */ |
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163 | |
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164 | #define REGNO_LAST_UID(N) (reg_n_info[(N)].last_uid) |
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165 | |
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166 | /* Similar, but includes insns that mention the reg in their notes. */ |
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167 | |
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168 | #define REGNO_LAST_NOTE_UID(N) (reg_n_info[(N)].last_note_uid) |
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169 | |
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170 | /* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function. |
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171 | After rtl generation, it is 1 plus the largest register number used. */ |
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172 | |
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173 | extern int reg_rtx_no; |
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174 | |
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175 | /* Vector indexed by regno; contains 1 for a register is considered a pointer. |
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176 | Reloading, etc. will use a pointer register rather than a non-pointer |
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177 | as the base register in an address, when there is a choice of two regs. */ |
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178 | |
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179 | extern char *regno_pointer_flag; |
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180 | #define REGNO_POINTER_FLAG(REGNO) regno_pointer_flag[REGNO] |
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181 | extern int regno_pointer_flag_length; |
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182 | |
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183 | /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers |
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184 | that have to go in the same hard reg. */ |
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185 | extern rtx regs_may_share; |
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186 | |
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187 | /* Vector mapping pseudo regno into the REG rtx for that register. |
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188 | This is computed by reg_scan. */ |
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189 | |
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190 | extern rtx *regno_reg_rtx; |
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191 | |
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192 | /* Flag set by local-alloc or global-alloc if they decide to allocate |
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193 | something in a call-clobbered register. */ |
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194 | |
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195 | extern int caller_save_needed; |
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196 | |
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197 | /* Predicate to decide whether to give a hard reg to a pseudo which |
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198 | is referenced REFS times and would need to be saved and restored |
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199 | around a call CALLS times. */ |
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200 | |
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201 | #ifndef CALLER_SAVE_PROFITABLE |
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202 | #define CALLER_SAVE_PROFITABLE(REFS, CALLS) (4 * (CALLS) < (REFS)) |
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203 | #endif |
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204 | |
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205 | /* On most machines a register class is likely to be spilled if it |
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206 | only has one register. */ |
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207 | #ifndef CLASS_LIKELY_SPILLED_P |
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208 | #define CLASS_LIKELY_SPILLED_P(CLASS) (reg_class_size[(int) (CLASS)] == 1) |
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209 | #endif |
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210 | |
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211 | /* Allocated in local_alloc. */ |
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212 | |
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213 | /* A list of SCRATCH rtl allocated by local-alloc. */ |
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214 | extern rtx *scratch_list; |
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215 | /* The basic block in which each SCRATCH is used. */ |
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216 | extern int *scratch_block; |
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217 | /* The length of the arrays pointed to by scratch_block and scratch_list. */ |
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218 | extern int scratch_list_length; |
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219 | |
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220 | /* Allocate reg_n_info tables */ |
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221 | extern void allocate_reg_info PROTO((int, int, int)); |
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