[8833] | 1 | /* Dummy data flow analysis for GNU compiler in nonoptimizing mode. |
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[11287] | 2 | Copyright (C) 1987, 91, 94, 95, 96, 1997 Free Software Foundation, Inc. |
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[8833] | 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 | /* This file performs stupid register allocation, which is used |
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| 23 | when cc1 gets the -noreg switch (which is when cc does not get -O). |
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| 24 | |
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| 25 | Stupid register allocation goes in place of the the flow_analysis, |
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| 26 | local_alloc and global_alloc passes. combine_instructions cannot |
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| 27 | be done with stupid allocation because the data flow info that it needs |
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| 28 | is not computed here. |
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| 29 | |
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| 30 | In stupid allocation, the only user-defined variables that can |
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| 31 | go in registers are those declared "register". They are assumed |
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| 32 | to have a life span equal to their scope. Other user variables |
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| 33 | are given stack slots in the rtl-generation pass and are not |
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| 34 | represented as pseudo regs. A compiler-generated temporary |
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| 35 | is assumed to live from its first mention to its last mention. |
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| 36 | |
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| 37 | Since each pseudo-reg's life span is just an interval, it can be |
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| 38 | represented as a pair of numbers, each of which identifies an insn by |
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| 39 | its position in the function (number of insns before it). The first |
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| 40 | thing done for stupid allocation is to compute such a number for each |
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| 41 | insn. It is called the suid. Then the life-interval of each |
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| 42 | pseudo reg is computed. Then the pseudo regs are ordered by priority |
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| 43 | and assigned hard regs in priority order. */ |
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| 44 | |
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[11287] | 45 | #include "config.h" |
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[8833] | 46 | #include <stdio.h> |
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| 47 | #include "rtl.h" |
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| 48 | #include "hard-reg-set.h" |
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| 49 | #include "regs.h" |
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| 50 | #include "flags.h" |
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| 51 | |
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| 52 | /* Vector mapping INSN_UIDs to suids. |
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| 53 | The suids are like uids but increase monotonically always. |
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| 54 | We use them to see whether a subroutine call came |
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| 55 | between a variable's birth and its death. */ |
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| 56 | |
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| 57 | static int *uid_suid; |
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| 58 | |
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| 59 | /* Get the suid of an insn. */ |
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| 60 | |
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| 61 | #define INSN_SUID(INSN) (uid_suid[INSN_UID (INSN)]) |
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| 62 | |
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| 63 | /* Record the suid of the last CALL_INSN |
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| 64 | so we can tell whether a pseudo reg crosses any calls. */ |
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| 65 | |
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| 66 | static int last_call_suid; |
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| 67 | |
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[11287] | 68 | /* Record the suid of the last NOTE_INSN_SETJMP |
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| 69 | so we can tell whether a pseudo reg crosses any setjmp. */ |
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| 70 | |
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| 71 | static int last_setjmp_suid; |
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| 72 | |
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[8833] | 73 | /* Element N is suid of insn where life span of pseudo reg N ends. |
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| 74 | Element is 0 if register N has not been seen yet on backward scan. */ |
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| 75 | |
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| 76 | static int *reg_where_dead; |
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| 77 | |
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| 78 | /* Element N is suid of insn where life span of pseudo reg N begins. */ |
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| 79 | |
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| 80 | static int *reg_where_born; |
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| 81 | |
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| 82 | /* Numbers of pseudo-regs to be allocated, highest priority first. */ |
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| 83 | |
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| 84 | static int *reg_order; |
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| 85 | |
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| 86 | /* Indexed by reg number (hard or pseudo), nonzero if register is live |
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| 87 | at the current point in the instruction stream. */ |
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| 88 | |
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| 89 | static char *regs_live; |
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| 90 | |
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| 91 | /* Indexed by reg number, nonzero if reg was used in a SUBREG that changes |
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| 92 | its size. */ |
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| 93 | |
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| 94 | static char *regs_change_size; |
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| 95 | |
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[11287] | 96 | /* Indexed by reg number, nonzero if reg crosses a setjmp. */ |
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| 97 | |
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| 98 | static char *regs_crosses_setjmp; |
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| 99 | |
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[8833] | 100 | /* Indexed by insn's suid, the set of hard regs live after that insn. */ |
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| 101 | |
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| 102 | static HARD_REG_SET *after_insn_hard_regs; |
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| 103 | |
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| 104 | /* Record that hard reg REGNO is live after insn INSN. */ |
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| 105 | |
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| 106 | #define MARK_LIVE_AFTER(INSN,REGNO) \ |
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| 107 | SET_HARD_REG_BIT (after_insn_hard_regs[INSN_SUID (INSN)], (REGNO)) |
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| 108 | |
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[11287] | 109 | static int stupid_reg_compare PROTO((const GENERIC_PTR,const GENERIC_PTR)); |
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[8833] | 110 | static int stupid_find_reg PROTO((int, enum reg_class, enum machine_mode, |
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| 111 | int, int, int)); |
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| 112 | static void stupid_mark_refs PROTO((rtx, rtx)); |
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| 113 | |
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| 114 | /* Stupid life analysis is for the case where only variables declared |
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| 115 | `register' go in registers. For this case, we mark all |
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| 116 | pseudo-registers that belong to register variables as |
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| 117 | dying in the last instruction of the function, and all other |
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| 118 | pseudo registers as dying in the last place they are referenced. |
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| 119 | Hard registers are marked as dying in the last reference before |
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| 120 | the end or before each store into them. */ |
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| 121 | |
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| 122 | void |
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| 123 | stupid_life_analysis (f, nregs, file) |
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| 124 | rtx f; |
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| 125 | int nregs; |
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| 126 | FILE *file; |
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| 127 | { |
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| 128 | register int i; |
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| 129 | register rtx last, insn; |
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| 130 | int max_uid, max_suid; |
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| 131 | |
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| 132 | bzero (regs_ever_live, sizeof regs_ever_live); |
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| 133 | |
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| 134 | regs_live = (char *) alloca (nregs); |
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| 135 | |
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| 136 | /* First find the last real insn, and count the number of insns, |
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| 137 | and assign insns their suids. */ |
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| 138 | |
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| 139 | for (insn = f, i = 0; insn; insn = NEXT_INSN (insn)) |
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| 140 | if (INSN_UID (insn) > i) |
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| 141 | i = INSN_UID (insn); |
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| 142 | |
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| 143 | max_uid = i + 1; |
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| 144 | uid_suid = (int *) alloca ((i + 1) * sizeof (int)); |
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| 145 | |
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| 146 | /* Compute the mapping from uids to suids. |
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| 147 | Suids are numbers assigned to insns, like uids, |
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| 148 | except that suids increase monotonically through the code. */ |
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| 149 | |
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| 150 | last = 0; /* In case of empty function body */ |
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| 151 | for (insn = f, i = 0; insn; insn = NEXT_INSN (insn)) |
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| 152 | { |
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| 153 | if (GET_RTX_CLASS (GET_CODE (insn)) == 'i') |
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| 154 | last = insn; |
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| 155 | |
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| 156 | INSN_SUID (insn) = ++i; |
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| 157 | } |
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| 158 | |
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| 159 | last_call_suid = i + 1; |
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[11287] | 160 | last_setjmp_suid = i + 1; |
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[8833] | 161 | max_suid = i + 1; |
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| 162 | |
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| 163 | max_regno = nregs; |
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| 164 | |
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| 165 | /* Allocate tables to record info about regs. */ |
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| 166 | |
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| 167 | reg_where_dead = (int *) alloca (nregs * sizeof (int)); |
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| 168 | bzero ((char *) reg_where_dead, nregs * sizeof (int)); |
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| 169 | |
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| 170 | reg_where_born = (int *) alloca (nregs * sizeof (int)); |
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| 171 | bzero ((char *) reg_where_born, nregs * sizeof (int)); |
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| 172 | |
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| 173 | reg_order = (int *) alloca (nregs * sizeof (int)); |
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| 174 | bzero ((char *) reg_order, nregs * sizeof (int)); |
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| 175 | |
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| 176 | regs_change_size = (char *) alloca (nregs * sizeof (char)); |
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| 177 | bzero ((char *) regs_change_size, nregs * sizeof (char)); |
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| 178 | |
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[11287] | 179 | regs_crosses_setjmp = (char *) alloca (nregs * sizeof (char)); |
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| 180 | bzero ((char *) regs_crosses_setjmp, nregs * sizeof (char)); |
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| 181 | |
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| 182 | /* Allocate the reg_renumber array */ |
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| 183 | allocate_reg_info (max_regno, FALSE, TRUE); |
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[8833] | 184 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
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| 185 | reg_renumber[i] = i; |
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| 186 | |
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| 187 | after_insn_hard_regs |
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| 188 | = (HARD_REG_SET *) alloca (max_suid * sizeof (HARD_REG_SET)); |
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| 189 | |
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| 190 | bzero ((char *) after_insn_hard_regs, max_suid * sizeof (HARD_REG_SET)); |
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| 191 | |
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| 192 | /* Allocate and zero out many data structures |
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| 193 | that will record the data from lifetime analysis. */ |
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| 194 | |
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| 195 | allocate_for_life_analysis (); |
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| 196 | |
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| 197 | for (i = 0; i < max_regno; i++) |
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[11287] | 198 | REG_N_DEATHS (i) = 1; |
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[8833] | 199 | |
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| 200 | bzero (regs_live, nregs); |
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| 201 | |
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| 202 | /* Find where each pseudo register is born and dies, |
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| 203 | by scanning all insns from the end to the start |
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| 204 | and noting all mentions of the registers. |
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| 205 | |
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| 206 | Also find where each hard register is live |
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| 207 | and record that info in after_insn_hard_regs. |
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| 208 | regs_live[I] is 1 if hard reg I is live |
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| 209 | at the current point in the scan. */ |
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| 210 | |
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| 211 | for (insn = last; insn; insn = PREV_INSN (insn)) |
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| 212 | { |
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| 213 | register HARD_REG_SET *p = after_insn_hard_regs + INSN_SUID (insn); |
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| 214 | |
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| 215 | /* Copy the info in regs_live into the element of after_insn_hard_regs |
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| 216 | for the current position in the rtl code. */ |
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| 217 | |
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| 218 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
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| 219 | if (regs_live[i]) |
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| 220 | SET_HARD_REG_BIT (*p, i); |
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| 221 | |
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| 222 | /* Update which hard regs are currently live |
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| 223 | and also the birth and death suids of pseudo regs |
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| 224 | based on the pattern of this insn. */ |
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| 225 | |
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| 226 | if (GET_RTX_CLASS (GET_CODE (insn)) == 'i') |
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| 227 | stupid_mark_refs (PATTERN (insn), insn); |
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| 228 | |
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[11287] | 229 | if (GET_CODE (insn) == NOTE |
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| 230 | && NOTE_LINE_NUMBER (insn) == NOTE_INSN_SETJMP) |
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| 231 | last_setjmp_suid = INSN_SUID (insn); |
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| 232 | |
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[8833] | 233 | /* Mark all call-clobbered regs as live after each call insn |
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| 234 | so that a pseudo whose life span includes this insn |
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| 235 | will not go in one of them. |
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| 236 | Then mark those regs as all dead for the continuing scan |
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| 237 | of the insns before the call. */ |
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| 238 | |
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| 239 | if (GET_CODE (insn) == CALL_INSN) |
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| 240 | { |
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| 241 | last_call_suid = INSN_SUID (insn); |
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| 242 | IOR_HARD_REG_SET (after_insn_hard_regs[last_call_suid], |
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| 243 | call_used_reg_set); |
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| 244 | |
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| 245 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
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| 246 | if (call_used_regs[i]) |
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| 247 | regs_live[i] = 0; |
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| 248 | |
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| 249 | /* It is important that this be done after processing the insn's |
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| 250 | pattern because we want the function result register to still |
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| 251 | be live if it's also used to pass arguments. */ |
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| 252 | stupid_mark_refs (CALL_INSN_FUNCTION_USAGE (insn), insn); |
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| 253 | } |
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| 254 | } |
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| 255 | |
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| 256 | /* Now decide the order in which to allocate the pseudo registers. */ |
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| 257 | |
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| 258 | for (i = LAST_VIRTUAL_REGISTER + 1; i < max_regno; i++) |
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| 259 | reg_order[i] = i; |
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| 260 | |
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| 261 | qsort (®_order[LAST_VIRTUAL_REGISTER + 1], |
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| 262 | max_regno - LAST_VIRTUAL_REGISTER - 1, sizeof (int), |
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| 263 | stupid_reg_compare); |
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| 264 | |
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| 265 | /* Now, in that order, try to find hard registers for those pseudo regs. */ |
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| 266 | |
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| 267 | for (i = LAST_VIRTUAL_REGISTER + 1; i < max_regno; i++) |
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| 268 | { |
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| 269 | register int r = reg_order[i]; |
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| 270 | |
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[11287] | 271 | /* Some regnos disappear from the rtl. Ignore them to avoid crash. |
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| 272 | Also don't allocate registers that cross a setjmp, or live across |
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| 273 | a call if this function receives a nonlocal goto. */ |
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| 274 | if (regno_reg_rtx[r] == 0 || regs_crosses_setjmp[r] |
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| 275 | || (REG_N_CALLS_CROSSED (r) > 0 |
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| 276 | && current_function_has_nonlocal_label)) |
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[8833] | 277 | continue; |
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| 278 | |
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| 279 | /* Now find the best hard-register class for this pseudo register */ |
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| 280 | if (N_REG_CLASSES > 1) |
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[11287] | 281 | reg_renumber[r] = stupid_find_reg (REG_N_CALLS_CROSSED (r), |
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[8833] | 282 | reg_preferred_class (r), |
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| 283 | PSEUDO_REGNO_MODE (r), |
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| 284 | reg_where_born[r], |
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| 285 | reg_where_dead[r], |
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| 286 | regs_change_size[r]); |
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| 287 | |
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| 288 | /* If no reg available in that class, try alternate class. */ |
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| 289 | if (reg_renumber[r] == -1 && reg_alternate_class (r) != NO_REGS) |
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[11287] | 290 | reg_renumber[r] = stupid_find_reg (REG_N_CALLS_CROSSED (r), |
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[8833] | 291 | reg_alternate_class (r), |
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| 292 | PSEUDO_REGNO_MODE (r), |
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| 293 | reg_where_born[r], |
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| 294 | reg_where_dead[r], |
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| 295 | regs_change_size[r]); |
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| 296 | } |
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| 297 | |
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| 298 | if (file) |
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| 299 | dump_flow_info (file); |
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| 300 | } |
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| 301 | |
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| 302 | /* Comparison function for qsort. |
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| 303 | Returns -1 (1) if register *R1P is higher priority than *R2P. */ |
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| 304 | |
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| 305 | static int |
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| 306 | stupid_reg_compare (r1p, r2p) |
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[11287] | 307 | const GENERIC_PTR r1p; |
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| 308 | const GENERIC_PTR r2p; |
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[8833] | 309 | { |
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[11287] | 310 | register int r1 = *(int *)r1p, r2 = *(int *)r2p; |
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[8833] | 311 | register int len1 = reg_where_dead[r1] - reg_where_born[r1]; |
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| 312 | register int len2 = reg_where_dead[r2] - reg_where_born[r2]; |
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| 313 | int tem; |
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| 314 | |
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| 315 | tem = len2 - len1; |
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| 316 | if (tem != 0) |
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| 317 | return tem; |
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| 318 | |
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[11287] | 319 | tem = REG_N_REFS (r1) - REG_N_REFS (r2); |
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[8833] | 320 | if (tem != 0) |
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| 321 | return tem; |
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| 322 | |
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| 323 | /* If regs are equally good, sort by regno, |
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| 324 | so that the results of qsort leave nothing to chance. */ |
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| 325 | return r1 - r2; |
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| 326 | } |
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| 327 | |
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| 328 | /* Find a block of SIZE words of hard registers in reg_class CLASS |
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| 329 | that can hold a value of machine-mode MODE |
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| 330 | (but actually we test only the first of the block for holding MODE) |
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[11287] | 331 | currently free from after insn whose suid is BORN_INSN |
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| 332 | through the insn whose suid is DEAD_INSN, |
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[8833] | 333 | and return the number of the first of them. |
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| 334 | Return -1 if such a block cannot be found. |
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| 335 | |
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| 336 | If CALL_PRESERVED is nonzero, insist on registers preserved |
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| 337 | over subroutine calls, and return -1 if cannot find such. |
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| 338 | |
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| 339 | If CHANGES_SIZE is nonzero, it means this register was used as the |
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| 340 | operand of a SUBREG that changes its size. */ |
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| 341 | |
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| 342 | static int |
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| 343 | stupid_find_reg (call_preserved, class, mode, |
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| 344 | born_insn, dead_insn, changes_size) |
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| 345 | int call_preserved; |
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| 346 | enum reg_class class; |
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| 347 | enum machine_mode mode; |
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| 348 | int born_insn, dead_insn; |
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| 349 | int changes_size; |
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| 350 | { |
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| 351 | register int i, ins; |
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| 352 | #ifdef HARD_REG_SET |
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| 353 | register /* Declare them register if they are scalars. */ |
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| 354 | #endif |
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| 355 | HARD_REG_SET used, this_reg; |
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| 356 | #ifdef ELIMINABLE_REGS |
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| 357 | static struct {int from, to; } eliminables[] = ELIMINABLE_REGS; |
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| 358 | #endif |
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| 359 | |
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[11287] | 360 | /* If this register's life is more than 5,000 insns, we probably |
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| 361 | can't allocate it, so don't waste the time trying. This avoids |
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| 362 | quadratic behavior on programs that have regularly-occurring |
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| 363 | SAVE_EXPRs. */ |
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| 364 | if (dead_insn > born_insn + 5000) |
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| 365 | return -1; |
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| 366 | |
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[8833] | 367 | COPY_HARD_REG_SET (used, |
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| 368 | call_preserved ? call_used_reg_set : fixed_reg_set); |
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| 369 | |
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| 370 | #ifdef ELIMINABLE_REGS |
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| 371 | for (i = 0; i < sizeof eliminables / sizeof eliminables[0]; i++) |
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| 372 | SET_HARD_REG_BIT (used, eliminables[i].from); |
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| 373 | #if HARD_FRAME_POINTER_REGNUM != FRAME_POINTER_REGNUM |
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| 374 | SET_HARD_REG_BIT (used, HARD_FRAME_POINTER_REGNUM); |
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| 375 | #endif |
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| 376 | #else |
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| 377 | SET_HARD_REG_BIT (used, FRAME_POINTER_REGNUM); |
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| 378 | #endif |
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| 379 | |
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| 380 | for (ins = born_insn; ins < dead_insn; ins++) |
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| 381 | IOR_HARD_REG_SET (used, after_insn_hard_regs[ins]); |
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| 382 | |
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| 383 | IOR_COMPL_HARD_REG_SET (used, reg_class_contents[(int) class]); |
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| 384 | |
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| 385 | #ifdef CLASS_CANNOT_CHANGE_SIZE |
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| 386 | if (changes_size) |
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| 387 | IOR_HARD_REG_SET (used, |
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| 388 | reg_class_contents[(int) CLASS_CANNOT_CHANGE_SIZE]); |
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| 389 | #endif |
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| 390 | |
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| 391 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
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| 392 | { |
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| 393 | #ifdef REG_ALLOC_ORDER |
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| 394 | int regno = reg_alloc_order[i]; |
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| 395 | #else |
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| 396 | int regno = i; |
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| 397 | #endif |
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| 398 | |
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| 399 | /* If a register has screwy overlap problems, |
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| 400 | don't use it at all if not optimizing. |
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| 401 | Actually this is only for the 387 stack register, |
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| 402 | and it's because subsequent code won't work. */ |
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| 403 | #ifdef OVERLAPPING_REGNO_P |
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| 404 | if (OVERLAPPING_REGNO_P (regno)) |
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| 405 | continue; |
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| 406 | #endif |
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| 407 | |
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| 408 | if (! TEST_HARD_REG_BIT (used, regno) |
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| 409 | && HARD_REGNO_MODE_OK (regno, mode)) |
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| 410 | { |
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| 411 | register int j; |
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| 412 | register int size1 = HARD_REGNO_NREGS (regno, mode); |
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| 413 | for (j = 1; j < size1 && ! TEST_HARD_REG_BIT (used, regno + j); j++); |
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| 414 | if (j == size1) |
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| 415 | { |
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| 416 | CLEAR_HARD_REG_SET (this_reg); |
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| 417 | while (--j >= 0) |
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| 418 | SET_HARD_REG_BIT (this_reg, regno + j); |
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| 419 | for (ins = born_insn; ins < dead_insn; ins++) |
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| 420 | { |
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| 421 | IOR_HARD_REG_SET (after_insn_hard_regs[ins], this_reg); |
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| 422 | } |
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| 423 | return regno; |
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| 424 | } |
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| 425 | #ifndef REG_ALLOC_ORDER |
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| 426 | i += j; /* Skip starting points we know will lose */ |
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| 427 | #endif |
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| 428 | } |
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| 429 | } |
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| 430 | |
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| 431 | return -1; |
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| 432 | } |
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| 433 | |
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| 434 | /* Walk X, noting all assignments and references to registers |
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| 435 | and recording what they imply about life spans. |
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| 436 | INSN is the current insn, supplied so we can find its suid. */ |
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| 437 | |
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| 438 | static void |
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| 439 | stupid_mark_refs (x, insn) |
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| 440 | rtx x, insn; |
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| 441 | { |
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| 442 | register RTX_CODE code; |
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| 443 | register char *fmt; |
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| 444 | register int regno, i; |
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| 445 | |
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| 446 | if (x == 0) |
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| 447 | return; |
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| 448 | |
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| 449 | code = GET_CODE (x); |
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| 450 | |
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| 451 | if (code == SET || code == CLOBBER) |
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| 452 | { |
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| 453 | if (SET_DEST (x) != 0 |
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| 454 | && (GET_CODE (SET_DEST (x)) == REG |
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| 455 | || (GET_CODE (SET_DEST (x)) == SUBREG |
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| 456 | && GET_CODE (SUBREG_REG (SET_DEST (x))) == REG |
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| 457 | && (REGNO (SUBREG_REG (SET_DEST (x))) |
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| 458 | >= FIRST_PSEUDO_REGISTER)))) |
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| 459 | { |
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| 460 | /* Register is being assigned. */ |
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| 461 | /* If setting a SUBREG, we treat the entire reg as being set. */ |
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| 462 | if (GET_CODE (SET_DEST (x)) == SUBREG) |
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| 463 | regno = REGNO (SUBREG_REG (SET_DEST (x))); |
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| 464 | else |
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| 465 | regno = REGNO (SET_DEST (x)); |
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| 466 | |
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| 467 | /* For hard regs, update the where-live info. */ |
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| 468 | if (regno < FIRST_PSEUDO_REGISTER) |
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| 469 | { |
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| 470 | register int j |
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| 471 | = HARD_REGNO_NREGS (regno, GET_MODE (SET_DEST (x))); |
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| 472 | |
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| 473 | while (--j >= 0) |
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| 474 | { |
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| 475 | regs_ever_live[regno+j] = 1; |
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| 476 | regs_live[regno+j] = 0; |
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| 477 | |
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| 478 | /* The following line is for unused outputs; |
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| 479 | they do get stored even though never used again. */ |
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[11287] | 480 | MARK_LIVE_AFTER (insn, regno+j); |
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[8833] | 481 | |
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| 482 | /* When a hard reg is clobbered, mark it in use |
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| 483 | just before this insn, so it is live all through. */ |
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| 484 | if (code == CLOBBER && INSN_SUID (insn) > 0) |
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| 485 | SET_HARD_REG_BIT (after_insn_hard_regs[INSN_SUID (insn) - 1], |
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[11287] | 486 | regno+j); |
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[8833] | 487 | } |
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| 488 | } |
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| 489 | /* For pseudo regs, record where born, where dead, number of |
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| 490 | times used, and whether live across a call. */ |
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| 491 | else |
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| 492 | { |
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| 493 | /* Update the life-interval bounds of this pseudo reg. */ |
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| 494 | |
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| 495 | /* When a pseudo-reg is CLOBBERed, it is born just before |
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| 496 | the clobbering insn. When setting, just after. */ |
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| 497 | int where_born = INSN_SUID (insn) - (code == CLOBBER); |
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| 498 | |
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| 499 | reg_where_born[regno] = where_born; |
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| 500 | |
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| 501 | /* The reg must live at least one insn even |
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| 502 | in it is never again used--because it has to go |
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| 503 | in SOME hard reg. Mark it as dying after the current |
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| 504 | insn so that it will conflict with any other outputs of |
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| 505 | this insn. */ |
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| 506 | if (reg_where_dead[regno] < where_born + 2) |
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| 507 | { |
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| 508 | reg_where_dead[regno] = where_born + 2; |
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| 509 | regs_live[regno] = 1; |
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| 510 | } |
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| 511 | |
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| 512 | /* Count the refs of this reg. */ |
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[11287] | 513 | REG_N_REFS (regno)++; |
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[8833] | 514 | |
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| 515 | if (last_call_suid < reg_where_dead[regno]) |
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[11287] | 516 | REG_N_CALLS_CROSSED (regno) += 1; |
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| 517 | |
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| 518 | if (last_setjmp_suid < reg_where_dead[regno]) |
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| 519 | regs_crosses_setjmp[regno] = 1; |
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| 520 | |
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| 521 | /* If this register is only used in this insn and is only |
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| 522 | set, mark it unused. We have to do this even when not |
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| 523 | optimizing so that MD patterns which count on this |
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| 524 | behavior (e.g., it not causing an output reload on |
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| 525 | an insn setting CC) will operate correctly. */ |
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| 526 | if (GET_CODE (SET_DEST (x)) == REG |
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| 527 | && REGNO_FIRST_UID (regno) == INSN_UID (insn) |
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| 528 | && REGNO_LAST_UID (regno) == INSN_UID (insn) |
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| 529 | && (code == CLOBBER || ! reg_mentioned_p (SET_DEST (x), |
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| 530 | SET_SRC (x)))) |
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| 531 | REG_NOTES (insn) = gen_rtx (EXPR_LIST, REG_UNUSED, |
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| 532 | SET_DEST (x), REG_NOTES (insn)); |
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[8833] | 533 | } |
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| 534 | } |
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| 535 | |
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| 536 | /* Record references from the value being set, |
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| 537 | or from addresses in the place being set if that's not a reg. |
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| 538 | If setting a SUBREG, we treat the entire reg as *used*. */ |
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| 539 | if (code == SET) |
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| 540 | { |
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| 541 | stupid_mark_refs (SET_SRC (x), insn); |
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| 542 | if (GET_CODE (SET_DEST (x)) != REG) |
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| 543 | stupid_mark_refs (SET_DEST (x), insn); |
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| 544 | } |
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| 545 | return; |
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| 546 | } |
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| 547 | |
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| 548 | else if (code == SUBREG |
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| 549 | && GET_CODE (SUBREG_REG (x)) == REG |
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| 550 | && REGNO (SUBREG_REG (x)) >= FIRST_PSEUDO_REGISTER |
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| 551 | && (GET_MODE_SIZE (GET_MODE (x)) |
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| 552 | != GET_MODE_SIZE (GET_MODE (SUBREG_REG (x)))) |
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| 553 | && (INTEGRAL_MODE_P (GET_MODE (x)) |
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| 554 | || INTEGRAL_MODE_P (GET_MODE (SUBREG_REG (x))))) |
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| 555 | regs_change_size[REGNO (SUBREG_REG (x))] = 1; |
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| 556 | |
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| 557 | /* Register value being used, not set. */ |
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| 558 | |
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| 559 | else if (code == REG) |
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| 560 | { |
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| 561 | regno = REGNO (x); |
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| 562 | if (regno < FIRST_PSEUDO_REGISTER) |
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| 563 | { |
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| 564 | /* Hard reg: mark it live for continuing scan of previous insns. */ |
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| 565 | register int j = HARD_REGNO_NREGS (regno, GET_MODE (x)); |
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| 566 | while (--j >= 0) |
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| 567 | { |
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| 568 | regs_ever_live[regno+j] = 1; |
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| 569 | regs_live[regno+j] = 1; |
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| 570 | } |
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| 571 | } |
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| 572 | else |
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| 573 | { |
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| 574 | /* Pseudo reg: record first use, last use and number of uses. */ |
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| 575 | |
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| 576 | reg_where_born[regno] = INSN_SUID (insn); |
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[11287] | 577 | REG_N_REFS (regno)++; |
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[8833] | 578 | if (regs_live[regno] == 0) |
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| 579 | { |
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| 580 | regs_live[regno] = 1; |
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| 581 | reg_where_dead[regno] = INSN_SUID (insn); |
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| 582 | } |
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| 583 | } |
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| 584 | return; |
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| 585 | } |
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| 586 | |
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| 587 | /* Recursive scan of all other rtx's. */ |
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| 588 | |
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| 589 | fmt = GET_RTX_FORMAT (code); |
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| 590 | for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--) |
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| 591 | { |
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| 592 | if (fmt[i] == 'e') |
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| 593 | stupid_mark_refs (XEXP (x, i), insn); |
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| 594 | if (fmt[i] == 'E') |
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| 595 | { |
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| 596 | register int j; |
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| 597 | for (j = XVECLEN (x, i) - 1; j >= 0; j--) |
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| 598 | stupid_mark_refs (XVECEXP (x, i, j), insn); |
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| 599 | } |
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| 600 | } |
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| 601 | } |
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