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, 2004 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
27 #include "hard-reg-set.h"
28 #include "basic-block.h"
30 #define REG_BYTES(R) mode_size[(int) GET_MODE (R)]
32 /* When you only have the mode of a pseudo register before it has a hard
33 register chosen for it, this reports the size of each hard register
34 a pseudo in such a mode would get allocated to. A target may
37 #ifndef REGMODE_NATURAL_SIZE
38 #define REGMODE_NATURAL_SIZE(MODE) UNITS_PER_WORD
41 #ifndef SMALL_REGISTER_CLASSES
42 #define SMALL_REGISTER_CLASSES 0
45 /* Maximum register number used in this function, plus one. */
49 /* Register information indexed by register number */
50 typedef struct reg_info_def
51 { /* fields set by reg_scan */
52 int first_uid
; /* UID of first insn to use (REG n) */
53 int last_uid
; /* UID of last insn to use (REG n) */
55 /* fields set by reg_scan & flow_analysis */
56 int sets
; /* # of times (REG n) is set */
58 /* fields set by flow_analysis */
59 int refs
; /* # of times (REG n) is used or set */
60 int freq
; /* # estimated frequency (REG n) is used or set */
61 int deaths
; /* # of times (REG n) dies */
62 int live_length
; /* # of instructions (REG n) is live */
63 int calls_crossed
; /* # of calls (REG n) is live across */
64 int throw_calls_crossed
; /* # of calls that may throw (REG n) is live across */
65 int basic_block
; /* # of basic blocks (REG n) is used in */
68 extern varray_type reg_n_info
;
70 /* Indexed by n, gives number of times (REG n) is used or set. */
72 #define REG_N_REFS(N) (VARRAY_REG (reg_n_info, N)->refs)
74 /* Estimate frequency of references to register N. */
76 #define REG_FREQ(N) (VARRAY_REG (reg_n_info, N)->freq)
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
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
88 #define REG_FREQ_FROM_BB(bb) (optimize_size \
89 || (flag_branch_probabilities \
90 && !ENTRY_BLOCK_PTR->count) \
92 : ((bb)->frequency * REG_FREQ_MAX / BB_FREQ_MAX)\
93 ? ((bb)->frequency * REG_FREQ_MAX / BB_FREQ_MAX)\
96 /* Indexed by n, gives number of times (REG n) is set.
97 ??? both regscan and flow allocate space for this. We should settle
100 #define REG_N_SETS(N) (VARRAY_REG (reg_n_info, N)->sets)
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. */
108 #define REG_N_DEATHS(N) (VARRAY_REG (reg_n_info, N)->deaths)
110 /* Get the number of consecutive words required to hold pseudo-reg N. */
112 #define PSEUDO_REGNO_SIZE(N) \
113 ((GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) + UNITS_PER_WORD - 1) \
116 /* Get the number of bytes required to hold pseudo-reg N. */
118 #define PSEUDO_REGNO_BYTES(N) \
119 GET_MODE_SIZE (PSEUDO_REGNO_MODE (N))
121 /* Get the machine mode of pseudo-reg N. */
123 #define PSEUDO_REGNO_MODE(N) GET_MODE (regno_reg_rtx[N])
125 /* Indexed by N, gives number of CALL_INSNS across which (REG n) is live. */
127 #define REG_N_CALLS_CROSSED(N) (VARRAY_REG (reg_n_info, N)->calls_crossed)
129 /* Indexed by N, gives number of CALL_INSNS that may throw, across which
132 #define REG_N_THROWING_CALLS_CROSSED(N) \
133 (VARRAY_REG (reg_n_info, N)->throw_calls_crossed)
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.
141 local-alloc.c may alter this number to change the priority.
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. */
150 #define REG_LIVE_LENGTH(N) (VARRAY_REG (reg_n_info, N)->live_length)
152 /* Vector of substitutions of register numbers,
153 used to map pseudo regs into hardware regs.
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. */
159 extern short *reg_renumber
;
161 /* Vector indexed by hardware reg saying whether that reg is ever used. */
163 extern char regs_ever_live
[FIRST_PSEUDO_REGISTER
];
165 /* Like regs_ever_live, but saying whether reg is set by asm statements. */
167 extern char regs_asm_clobbered
[FIRST_PSEUDO_REGISTER
];
169 /* Vector indexed by machine mode saying whether there are regs of that mode. */
171 extern bool have_regs_of_mode
[MAX_MACHINE_MODE
];
173 /* For each hard register, the widest mode object that it can contain.
174 This will be a MODE_INT mode if the register can hold integers. Otherwise
175 it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the
178 extern enum machine_mode reg_raw_mode
[FIRST_PSEUDO_REGISTER
];
180 /* Vector indexed by regno; gives uid of first insn using that reg.
181 This is computed by reg_scan for use by cse and loop.
182 It is sometimes adjusted for subsequent changes during loop,
183 but not adjusted by cse even if cse invalidates it. */
185 #define REGNO_FIRST_UID(N) (VARRAY_REG (reg_n_info, N)->first_uid)
187 /* Vector indexed by regno; gives uid of last insn using that reg.
188 This is computed by reg_scan for use by cse and loop.
189 It is sometimes adjusted for subsequent changes during loop,
190 but not adjusted by cse even if cse invalidates it.
191 This is harmless since cse won't scan through a loop end. */
193 #define REGNO_LAST_UID(N) (VARRAY_REG (reg_n_info, N)->last_uid)
195 /* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
196 that have to go in the same hard reg. */
197 extern rtx regs_may_share
;
199 /* Flag set by local-alloc or global-alloc if they decide to allocate
200 something in a call-clobbered register. */
202 extern int caller_save_needed
;
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. */
208 #ifndef CALLER_SAVE_PROFITABLE
209 #define CALLER_SAVE_PROFITABLE(REFS, CALLS) (4 * (CALLS) < (REFS))
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)
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)
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
230 /* Allocate reg_n_info tables */
231 extern void allocate_reg_info (size_t, int, int);
233 /* Specify number of hard registers given machine mode occupy. */
234 extern unsigned char hard_regno_nregs
[FIRST_PSEUDO_REGISTER
][MAX_MACHINE_MODE
];
236 #endif /* GCC_REGS_H */