[gcc.git] / gcc / regs.h

/* Define per-register tables for data flow info and register allocation.
   Copyright (C) 1987, 1993, 1994, 1995 Free Software Foundation, Inc.

This file is part of GNU CC.

GNU CC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU CC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */


#define REG_BYTES(R) mode_size[(int) GET_MODE (R)]

/* Get the number of consecutive hard regs required to hold the REG rtx R.
   When something may be an explicit hard reg, REG_SIZE is the only
   valid way to get this value.  You cannot get it from the regno.  */

#define REG_SIZE(R) \
  ((mode_size[(int) GET_MODE (R)] + UNITS_PER_WORD - 1) / UNITS_PER_WORD)

/* Maximum register number used in this function, plus one.  */

extern int max_regno;

/* Maximum number of SCRATCH rtx's in each block of this function.  */

extern int max_scratch;

/* Indexed by n, gives number of times (REG n) is used or set.
   References within loops may be counted more times.  */

extern int *reg_n_refs;

/* Indexed by n, gives number of times (REG n) is set.  */

extern short *reg_n_sets;

/* Indexed by N, gives number of insns in which register N dies.
   Note that if register N is live around loops, it can die
   in transitions between basic blocks, and that is not counted here.
   So this is only a reliable indicator of how many regions of life there are
   for registers that are contained in one basic block.  */

extern short *reg_n_deaths;

/* Indexed by N; says whether a pseudo register N was ever used
   within a SUBREG that changes the size of the reg.  Some machines prohibit
   such objects to be in certain (usually floating-point) registers.  */

extern char *reg_changes_size;

/* Get the number of consecutive words required to hold pseudo-reg N.  */

#define PSEUDO_REGNO_SIZE(N) \
  ((GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) + UNITS_PER_WORD - 1)		\
   / UNITS_PER_WORD)

/* Get the number of bytes required to hold pseudo-reg N.  */

#define PSEUDO_REGNO_BYTES(N) \
  GET_MODE_SIZE (PSEUDO_REGNO_MODE (N))

/* Get the machine mode of pseudo-reg N.  */

#define PSEUDO_REGNO_MODE(N) GET_MODE (regno_reg_rtx[N])

/* Indexed by N, gives number of CALL_INSNS across which (REG n) is live.  */

extern int *reg_n_calls_crossed;

/* Total number of instructions at which (REG n) is live.
   The larger this is, the less priority (REG n) gets for
   allocation in a hard register (in global-alloc).
   This is set in flow.c and remains valid for the rest of the compilation
   of the function; it is used to control register allocation.

   local-alloc.c may alter this number to change the priority.

   Negative values are special.
   -1 is used to mark a pseudo reg which has a constant or memory equivalent
   and is used infrequently enough that it should not get a hard register.
   -2 is used to mark a pseudo reg for a parameter, when a frame pointer
   is not required.  global.c makes an allocno for this but does
   not try to assign a hard register to it.  */

extern int *reg_live_length;

/* Vector of substitutions of register numbers,
   used to map pseudo regs into hardware regs.  */

extern short *reg_renumber;

/* Vector indexed by hardware reg
   saying whether that reg is ever used.  */

extern char regs_ever_live[FIRST_PSEUDO_REGISTER];

/* Vector indexed by hardware reg giving its name.  */

extern char *reg_names[FIRST_PSEUDO_REGISTER];

/* For each hard register, the widest mode object that it can contain.
   This will be a MODE_INT mode if the register can hold integers.  Otherwise
   it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the
   register.  */

extern enum machine_mode reg_raw_mode[FIRST_PSEUDO_REGISTER];

/* Vector indexed by regno; gives uid of first insn using that reg.
   This is computed by reg_scan for use by cse and loop.
   It is sometimes adjusted for subsequent changes during loop,
   but not adjusted by cse even if cse invalidates it.  */

extern int *regno_first_uid;

/* Vector indexed by regno; gives uid of last insn using that reg.
   This is computed by reg_scan for use by cse and loop.
   It is sometimes adjusted for subsequent changes during loop,
   but not adjusted by cse even if cse invalidates it.
   This is harmless since cse won't scan through a loop end.  */

extern int *regno_last_uid;

/* Similar, but includes insns that mention the reg in their notes.  */

extern int *regno_last_note_uid;

/* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function.
   After rtl generation, it is 1 plus the largest register number used.  */

extern int reg_rtx_no;

/* Vector indexed by regno; contains 1 for a register is considered a pointer.
   Reloading, etc. will use a pointer register rather than a non-pointer
   as the base register in an address, when there is a choice of two regs.  */

extern char *regno_pointer_flag;
#define REGNO_POINTER_FLAG(REGNO) regno_pointer_flag[REGNO]
extern int regno_pointer_flag_length;

/* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
   that have to go in the same hard reg.  */
extern rtx regs_may_share;

/* Vector mapping pseudo regno into the REG rtx for that register.
   This is computed by reg_scan.  */

extern rtx *regno_reg_rtx;

/* Flag set by local-alloc or global-alloc if they decide to allocate
   something in a call-clobbered register.  */

extern int caller_save_needed;

/* Predicate to decide whether to give a hard reg to a pseudo which
   is referenced REFS times and would need to be saved and restored
   around a call CALLS times.  */

#ifndef CALLER_SAVE_PROFITABLE
#define CALLER_SAVE_PROFITABLE(REFS, CALLS)  (4 * (CALLS) < (REFS))
#endif

/* On most machines a register class is likely to be spilled if it
   only has one register.  */
#ifndef CLASS_LIKELY_SPILLED_P
#define CLASS_LIKELY_SPILLED_P(CLASS) (reg_class_size[(int) (CLASS)] == 1)
#endif

/* Allocated in local_alloc.  */

/* A list of SCRATCH rtl allocated by local-alloc.  */
extern rtx *scratch_list;
/* The basic block in which each SCRATCH is used.  */
extern int *scratch_block;
/* The length of the arrays pointed to by scratch_block and scratch_list.  */
extern int scratch_list_length;
Commit	Line	Data
c3bcc836	1	/* Define per-register tables for data flow info and register allocation.
40f954f6	2	Copyright (C) 1987, 1993, 1994, 1995 Free Software Foundation, Inc.
c3bcc836 RK	3
	4	This file is part of GNU CC.
	5
	6	GNU CC is free software; you can redistribute it and/or modify
	7	it under the terms of the GNU General Public License as published by
	8	the Free Software Foundation; either version 2, or (at your option)
	9	any later version.
	10
	11	GNU CC is distributed in the hope that it will be useful,
	12	but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	GNU General Public License for more details.
	15
	16	You should have received a copy of the GNU General Public License
	17	along with GNU CC; see the file COPYING. If not, write to
e99215a3 RK	18	the Free Software Foundation, 59 Temple Place - Suite 330,
e99215a3 RK	19	Boston, MA 02111-1307, USA. */
c3bcc836 RK	20
	21
	22
	23	#define REG_BYTES(R) mode_size[(int) GET_MODE (R)]
	24
	25	/* Get the number of consecutive hard regs required to hold the REG rtx R.
	26	When something may be an explicit hard reg, REG_SIZE is the only
	27	valid way to get this value. You cannot get it from the regno. */
	28
	29	#define REG_SIZE(R) \
	30	((mode_size[(int) GET_MODE (R)] + UNITS_PER_WORD - 1) / UNITS_PER_WORD)
	31
	32	/* Maximum register number used in this function, plus one. */
	33
	34	extern int max_regno;
	35
	36	/* Maximum number of SCRATCH rtx's in each block of this function. */
	37
	38	extern int max_scratch;
	39
	40	/* Indexed by n, gives number of times (REG n) is used or set.
	41	References within loops may be counted more times. */
	42
	43	extern int *reg_n_refs;
	44
	45	/* Indexed by n, gives number of times (REG n) is set. */
	46
	47	extern short *reg_n_sets;
	48
	49	/* Indexed by N, gives number of insns in which register N dies.
	50	Note that if register N is live around loops, it can die
	51	in transitions between basic blocks, and that is not counted here.
	52	So this is only a reliable indicator of how many regions of life there are
	53	for registers that are contained in one basic block. */
	54
	55	extern short *reg_n_deaths;
	56
9faa82d8	57	/* Indexed by N; says whether a pseudo register N was ever used
ffceec83 RK	58	within a SUBREG that changes the size of the reg. Some machines prohibit
	59	such objects to be in certain (usually floating-point) registers. */
	60
	61	extern char *reg_changes_size;
	62
c3bcc836 RK	63	/* Get the number of consecutive words required to hold pseudo-reg N. */
	64
	65	#define PSEUDO_REGNO_SIZE(N) \
	66	((GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) + UNITS_PER_WORD - 1) \
	67	/ UNITS_PER_WORD)
	68
	69	/* Get the number of bytes required to hold pseudo-reg N. */
	70
	71	#define PSEUDO_REGNO_BYTES(N) \
	72	GET_MODE_SIZE (PSEUDO_REGNO_MODE (N))
	73
	74	/* Get the machine mode of pseudo-reg N. */
	75
	76	#define PSEUDO_REGNO_MODE(N) GET_MODE (regno_reg_rtx[N])
	77
	78	/* Indexed by N, gives number of CALL_INSNS across which (REG n) is live. */
	79
	80	extern int *reg_n_calls_crossed;
	81
	82	/* Total number of instructions at which (REG n) is live.
	83	The larger this is, the less priority (REG n) gets for
	84	allocation in a hard register (in global-alloc).
	85	This is set in flow.c and remains valid for the rest of the compilation
	86	of the function; it is used to control register allocation.
	87
	88	local-alloc.c may alter this number to change the priority.
	89
	90	Negative values are special.
	91	-1 is used to mark a pseudo reg which has a constant or memory equivalent
	92	and is used infrequently enough that it should not get a hard register.
	93	-2 is used to mark a pseudo reg for a parameter, when a frame pointer
cfb2c0b1	94	is not required. global.c makes an allocno for this but does
c3bcc836 RK	95	not try to assign a hard register to it. */
	96
	97	extern int *reg_live_length;
	98
	99	/* Vector of substitutions of register numbers,
	100	used to map pseudo regs into hardware regs. */
	101
	102	extern short *reg_renumber;
	103
	104	/* Vector indexed by hardware reg
	105	saying whether that reg is ever used. */
	106
	107	extern char regs_ever_live[FIRST_PSEUDO_REGISTER];
	108
	109	/* Vector indexed by hardware reg giving its name. */
	110
	111	extern char *reg_names[FIRST_PSEUDO_REGISTER];
	112
04569dfb DE	113	/* For each hard register, the widest mode object that it can contain.
	114	This will be a MODE_INT mode if the register can hold integers. Otherwise
	115	it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the
	116	register. */
	117
	118	extern enum machine_mode reg_raw_mode[FIRST_PSEUDO_REGISTER];
	119
c3bcc836 RK	120	/* Vector indexed by regno; gives uid of first insn using that reg.
	121	This is computed by reg_scan for use by cse and loop.
	122	It is sometimes adjusted for subsequent changes during loop,
	123	but not adjusted by cse even if cse invalidates it. */
	124
819817b9	125	extern int *regno_first_uid;
c3bcc836 RK	126
	127	/* Vector indexed by regno; gives uid of last insn using that reg.
	128	This is computed by reg_scan for use by cse and loop.
	129	It is sometimes adjusted for subsequent changes during loop,
	130	but not adjusted by cse even if cse invalidates it.
	131	This is harmless since cse won't scan through a loop end. */
	132
819817b9	133	extern int *regno_last_uid;
c3bcc836	134
2cb547d8 RS	135	/* Similar, but includes insns that mention the reg in their notes. */
	136
	137	extern int *regno_last_note_uid;
	138
40f954f6 RK	139	/* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function.
	140	After rtl generation, it is 1 plus the largest register number used. */
	141
	142	extern int reg_rtx_no;
	143
c3bcc836 RK	144	/* Vector indexed by regno; contains 1 for a register is considered a pointer.
	145	Reloading, etc. will use a pointer register rather than a non-pointer
	146	as the base register in an address, when there is a choice of two regs. */
	147
	148	extern char *regno_pointer_flag;
	149	#define REGNO_POINTER_FLAG(REGNO) regno_pointer_flag[REGNO]
40f954f6 RK	150	extern int regno_pointer_flag_length;
40f954f6 RK	151
c3bcc836 RK	152	/* List made of EXPR_LIST rtx's which gives pairs of pseudo registers
	153	that have to go in the same hard reg. */
	154	extern rtx regs_may_share;
	155
	156	/* Vector mapping pseudo regno into the REG rtx for that register.
	157	This is computed by reg_scan. */
	158
	159	extern rtx *regno_reg_rtx;
	160
	161	/* Flag set by local-alloc or global-alloc if they decide to allocate
	162	something in a call-clobbered register. */
	163
	164	extern int caller_save_needed;
	165
	166	/* Predicate to decide whether to give a hard reg to a pseudo which
	167	is referenced REFS times and would need to be saved and restored
	168	around a call CALLS times. */
	169
	170	#ifndef CALLER_SAVE_PROFITABLE
	171	#define CALLER_SAVE_PROFITABLE(REFS, CALLS) (4 * (CALLS) < (REFS))
	172	#endif
a65b6597	173
6cad67d2 JL	174	/* On most machines a register class is likely to be spilled if it
	175	only has one register. */
	176	#ifndef CLASS_LIKELY_SPILLED_P
	177	#define CLASS_LIKELY_SPILLED_P(CLASS) (reg_class_size[(int) (CLASS)] == 1)
	178	#endif
	179
a65b6597 RK	180	/* Allocated in local_alloc. */
	181
	182	/* A list of SCRATCH rtl allocated by local-alloc. */
	183	extern rtx *scratch_list;
	184	/* The basic block in which each SCRATCH is used. */
	185	extern int *scratch_block;
	186	/* The length of the arrays pointed to by scratch_block and scratch_list. */
	187	extern int scratch_list_length;