[8833] | 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. */ |
---|
| 429 | bzero ((char *) local_reg_live_length, sizeof local_reg_live_length); |
---|
| 430 | bzero ((char *) local_reg_n_refs, sizeof local_reg_n_refs); |
---|
| 431 | for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++) |
---|
| 432 | if (reg_allocno[i] < 0 && reg_renumber[i] >= 0) |
---|
| 433 | { |
---|
| 434 | int regno = reg_renumber[i]; |
---|
| 435 | int endregno = regno + HARD_REGNO_NREGS (regno, PSEUDO_REGNO_MODE (i)); |
---|
| 436 | int j; |
---|
| 437 | |
---|
| 438 | for (j = regno; j < endregno; j++) |
---|
| 439 | { |
---|
| 440 | local_reg_n_refs[j] += reg_n_refs[i]; |
---|
| 441 | local_reg_live_length[j] += reg_live_length[i]; |
---|
| 442 | } |
---|
| 443 | } |
---|
| 444 | |
---|
| 445 | /* We can't override local-alloc for a reg used not just by local-alloc. */ |
---|
| 446 | for (i = 0; i < FIRST_PSEUDO_REGISTER; i++) |
---|
| 447 | if (regs_ever_live[i]) |
---|
| 448 | local_reg_n_refs[i] = 0; |
---|
| 449 | |
---|
| 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 | } |
---|