Merge branch 'master' of ssh://crater.dragonflybsd.org/repository/git/dragonfly
[dragonfly.git] / contrib / gcc-3.4 / gcc / regs.h
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1/* Define per-register tables for data flow info and register allocation.
2 Copyright (C) 1987, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2003 Free Software Foundation, Inc.
4
5This file is part of GCC.
6
7GCC is free software; you can redistribute it and/or modify it under
8the terms of the GNU General Public License as published by the Free
9Software Foundation; either version 2, or (at your option) any later
10version.
11
12GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13WARRANTY; without even the implied warranty of MERCHANTABILITY or
14FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15for more details.
16
17You should have received a copy of the GNU General Public License
18along with GCC; see the file COPYING. If not, write to the Free
19Software Foundation, 59 Temple Place - Suite 330, Boston, MA
2002111-1307, USA. */
21
22
23#include "varray.h"
24#include "hard-reg-set.h"
25#include "basic-block.h"
26
27#define REG_BYTES(R) mode_size[(int) GET_MODE (R)]
28
29/* When you only have the mode of a pseudo register before it has a hard
30 register chosen for it, this reports the size of each hard register
31 a pseudo in such a mode would get allocated to. A target may
32 override this. */
33
34#ifndef REGMODE_NATURAL_SIZE
35#define REGMODE_NATURAL_SIZE(MODE) UNITS_PER_WORD
36#endif
37
38#ifndef SMALL_REGISTER_CLASSES
39#define SMALL_REGISTER_CLASSES 0
40#endif
41
42/* Maximum register number used in this function, plus one. */
43
44extern int max_regno;
45
46/* Register information indexed by register number */
47typedef struct reg_info_def
48{ /* fields set by reg_scan */
49 int first_uid; /* UID of first insn to use (REG n) */
50 int last_uid; /* UID of last insn to use (REG n) */
51 int last_note_uid; /* UID of last note to use (REG n) */
52
53 /* fields set by reg_scan & flow_analysis */
54 int sets; /* # of times (REG n) is set */
55
56 /* fields set by flow_analysis */
57 int refs; /* # of times (REG n) is used or set */
58 int freq; /* # estimated frequency (REG n) is used or set */
59 int deaths; /* # of times (REG n) dies */
60 int live_length; /* # of instructions (REG n) is live */
61 int calls_crossed; /* # of calls (REG n) is live across */
1378ea41 62 int throw_calls_crossed; /* # of calls that may throw (REG n) is live across */
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63 int basic_block; /* # of basic blocks (REG n) is used in */
64 char changes_mode; /* whether (SUBREG (REG n)) exists and
65 is illegal. */
66} reg_info;
67
68extern varray_type reg_n_info;
69
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70/* Indexed by n, gives number of times (REG n) is used or set. */
71
72#define REG_N_REFS(N) (VARRAY_REG (reg_n_info, N)->refs)
73
74/* Estimate frequency of references to register N. */
75
76#define REG_FREQ(N) (VARRAY_REG (reg_n_info, N)->freq)
77
78/* The weights for each insn varries from 0 to REG_FREQ_BASE.
79 This constant does not need to be high, as in infrequently executed
80 regions we want to count instructions equivalently to optimize for
81 size instead of speed. */
82#define REG_FREQ_MAX 1000
83
84/* Compute register frequency from the BB frequency. When optimizing for size,
85 or profile driven feedback is available and the function is never executed,
86 frequency is always equivalent. Otherwise rescale the basic block
87 frequency. */
88#define REG_FREQ_FROM_BB(bb) (optimize_size \
89 || (flag_branch_probabilities \
90 && !ENTRY_BLOCK_PTR->count) \
91 ? REG_FREQ_MAX \
92 : ((bb)->frequency * REG_FREQ_MAX / BB_FREQ_MAX)\
93 ? ((bb)->frequency * REG_FREQ_MAX / BB_FREQ_MAX)\
94 : 1)
95
96/* Indexed by n, gives number of times (REG n) is set.
97 ??? both regscan and flow allocate space for this. We should settle
98 on just copy. */
99
100#define REG_N_SETS(N) (VARRAY_REG (reg_n_info, N)->sets)
101
102/* Indexed by N, gives number of insns in which register N dies.
103 Note that if register N is live around loops, it can die
104 in transitions between basic blocks, and that is not counted here.
105 So this is only a reliable indicator of how many regions of life there are
106 for registers that are contained in one basic block. */
107
108#define REG_N_DEATHS(N) (VARRAY_REG (reg_n_info, N)->deaths)
109
110/* Get the number of consecutive words required to hold pseudo-reg N. */
111
112#define PSEUDO_REGNO_SIZE(N) \
113 ((GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) + UNITS_PER_WORD - 1) \
114 / UNITS_PER_WORD)
115
116/* Get the number of bytes required to hold pseudo-reg N. */
117
118#define PSEUDO_REGNO_BYTES(N) \
119 GET_MODE_SIZE (PSEUDO_REGNO_MODE (N))
120
121/* Get the machine mode of pseudo-reg N. */
122
123#define PSEUDO_REGNO_MODE(N) GET_MODE (regno_reg_rtx[N])
124
125/* Indexed by N, gives number of CALL_INSNS across which (REG n) is live. */
126
127#define REG_N_CALLS_CROSSED(N) (VARRAY_REG (reg_n_info, N)->calls_crossed)
128
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129/* Indexed by N, gives number of CALL_INSNS that may throw, across which
130 (REG n) is live. */
131
132#define REG_N_THROWING_CALLS_CROSSED(N) \
133 (VARRAY_REG (reg_n_info, N)->throw_calls_crossed)
134
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135/* Total number of instructions at which (REG n) is live.
136 The larger this is, the less priority (REG n) gets for
137 allocation in a hard register (in global-alloc).
138 This is set in flow.c and remains valid for the rest of the compilation
139 of the function; it is used to control register allocation.
140
141 local-alloc.c may alter this number to change the priority.
142
143 Negative values are special.
144 -1 is used to mark a pseudo reg which has a constant or memory equivalent
145 and is used infrequently enough that it should not get a hard register.
146 -2 is used to mark a pseudo reg for a parameter, when a frame pointer
147 is not required. global.c makes an allocno for this but does
148 not try to assign a hard register to it. */
149
150#define REG_LIVE_LENGTH(N) (VARRAY_REG (reg_n_info, N)->live_length)
151
152/* Vector of substitutions of register numbers,
153 used to map pseudo regs into hardware regs.
154
155 This can't be folded into reg_n_info without changing all of the
156 machine dependent directories, since the reload functions
157 in the machine dependent files access it. */
158
159extern short *reg_renumber;
160
161/* Vector indexed by hardware reg saying whether that reg is ever used. */
162
163extern char regs_ever_live[FIRST_PSEUDO_REGISTER];
164
165/* Like regs_ever_live, but saying whether reg is set by asm statements. */
166
167extern char regs_asm_clobbered[FIRST_PSEUDO_REGISTER];
168
169/* For each hard register, the widest mode object that it can contain.
170 This will be a MODE_INT mode if the register can hold integers. Otherwise
171 it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the
172 register. */
173
174extern enum machine_mode reg_raw_mode[FIRST_PSEUDO_REGISTER];
175
176/* Vector indexed by regno; gives uid of first insn using that reg.
177 This is computed by reg_scan for use by cse and loop.
178 It is sometimes adjusted for subsequent changes during loop,
179 but not adjusted by cse even if cse invalidates it. */
180
181#define REGNO_FIRST_UID(N) (VARRAY_REG (reg_n_info, N)->first_uid)
182
183/* Vector indexed by regno; gives uid of last insn using that reg.
184 This is computed by reg_scan for use by cse and loop.
185 It is sometimes adjusted for subsequent changes during loop,
186 but not adjusted by cse even if cse invalidates it.
187 This is harmless since cse won't scan through a loop end. */
188
189#define REGNO_LAST_UID(N) (VARRAY_REG (reg_n_info, N)->last_uid)
190
191/* Similar, but includes insns that mention the reg in their notes. */
192
193#define REGNO_LAST_NOTE_UID(N) (VARRAY_REG (reg_n_info, N)->last_note_uid)
194
195/* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
196 that have to go in the same hard reg. */
197extern rtx regs_may_share;
198
199/* Flag set by local-alloc or global-alloc if they decide to allocate
200 something in a call-clobbered register. */
201
202extern int caller_save_needed;
203
204/* Predicate to decide whether to give a hard reg to a pseudo which
205 is referenced REFS times and would need to be saved and restored
206 around a call CALLS times. */
207
208#ifndef CALLER_SAVE_PROFITABLE
209#define CALLER_SAVE_PROFITABLE(REFS, CALLS) (4 * (CALLS) < (REFS))
210#endif
211
212/* On most machines a register class is likely to be spilled if it
213 only has one register. */
214#ifndef CLASS_LIKELY_SPILLED_P
215#define CLASS_LIKELY_SPILLED_P(CLASS) (reg_class_size[(int) (CLASS)] == 1)
216#endif
217
218/* Select a register mode required for caller save of hard regno REGNO. */
219#ifndef HARD_REGNO_CALLER_SAVE_MODE
220#define HARD_REGNO_CALLER_SAVE_MODE(REGNO, NREGS, MODE) \
221 choose_hard_reg_mode (REGNO, NREGS, false)
222#endif
223
224/* Registers that get partially clobbered by a call in a given mode.
225 These must not be call used registers. */
226#ifndef HARD_REGNO_CALL_PART_CLOBBERED
227#define HARD_REGNO_CALL_PART_CLOBBERED(REGNO, MODE) 0
228#endif
229
230/* Allocate reg_n_info tables */
231extern void allocate_reg_info (size_t, int, int);