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, 2005, 2006, 2007, 2008 Free Software
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
26 #include "hard-reg-set.h"
27 #include "basic-block.h"
29 #define REG_BYTES(R) mode_size[(int) GET_MODE (R)]
31 /* When you only have the mode of a pseudo register before it has a hard
32 register chosen for it, this reports the size of each hard register
33 a pseudo in such a mode would get allocated to. A target may
36 #ifndef REGMODE_NATURAL_SIZE
37 #define REGMODE_NATURAL_SIZE(MODE) UNITS_PER_WORD
40 #ifndef SMALL_REGISTER_CLASSES
41 #define SMALL_REGISTER_CLASSES 0
44 /* Maximum register number used in this function, plus one. */
48 /* REG_N_REFS and REG_N_SETS are initialized by a call to
49 regstat_init_n_sets_and_refs from the current values of
50 DF_REG_DEF_COUNT and DF_REG_USE_COUNT. REG_N_REFS and REG_N_SETS
51 should only be used if a pass need to change these values in some
52 magical way or or the pass needs to have accurate values for these
53 and is not using incremental df scanning.
55 At the end of a pass that uses REG_N_REFS and REG_N_SETS, a call
56 should be made to regstat_free_n_sets_and_refs.
58 Local alloc seems to play pretty loose with these values.
59 REG_N_REFS is set to 0 if the register is used in an asm.
60 Furthermore, local_alloc calls regclass to hack both REG_N_REFS and
61 REG_N_SETS for three address insns. Other passes seem to have
62 other special values. */
66 /* Structure to hold values for REG_N_SETS (i) and REG_N_REFS (i). */
68 struct regstat_n_sets_and_refs_t
70 int sets; /* # of times (REG n) is set */
71 int refs; /* # of times (REG n) is used or set */
74 extern struct regstat_n_sets_and_refs_t *regstat_n_sets_and_refs;
76 /* Indexed by n, gives number of times (REG n) is used or set. */
80 return regstat_n_sets_and_refs[regno].refs;
83 /* Indexed by n, gives number of times (REG n) is used or set. */
84 #define SET_REG_N_REFS(N,V) (regstat_n_sets_and_refs[N].refs = V)
85 #define INC_REG_N_REFS(N,V) (regstat_n_sets_and_refs[N].refs += V)
87 /* Indexed by n, gives number of times (REG n) is set. */
89 REG_N_SETS (int regno)
91 return regstat_n_sets_and_refs[regno].sets;
94 /* Indexed by n, gives number of times (REG n) is set. */
95 #define SET_REG_N_SETS(N,V) (regstat_n_sets_and_refs[N].sets = V)
96 #define INC_REG_N_SETS(N,V) (regstat_n_sets_and_refs[N].sets += V)
99 /* Functions defined in reg-stat.c. */
100 extern void regstat_init_n_sets_and_refs (void);
101 extern void regstat_free_n_sets_and_refs (void);
102 extern void regstat_compute_ri (void);
103 extern void regstat_free_ri (void);
104 extern bitmap regstat_get_setjmp_crosses (void);
105 extern void regstat_compute_calls_crossed (void);
106 extern void regstat_free_calls_crossed (void);
109 /* Register information indexed by register number. This structure is
110 initialized by calling regstat_compute_ri and is destroyed by
111 calling regstat_free_ri. */
114 int freq; /* # estimated frequency (REG n) is used or set */
115 int deaths; /* # of times (REG n) dies */
116 int live_length; /* # of instructions (REG n) is live */
117 int calls_crossed; /* # of calls (REG n) is live across */
118 int freq_calls_crossed; /* # estimated frequency (REG n) crosses call */
119 int throw_calls_crossed; /* # of calls that may throw (REG n) is live across */
120 int basic_block; /* # of basic blocks (REG n) is used in */
123 extern struct reg_info_t *reg_info_p;
125 /* The number allocated elements of reg_info_p. */
126 extern size_t reg_info_p_size;
128 /* Estimate frequency of references to register N. */
130 #define REG_FREQ(N) (reg_info_p[N].freq)
132 /* The weights for each insn varies from 0 to REG_FREQ_BASE.
133 This constant does not need to be high, as in infrequently executed
134 regions we want to count instructions equivalently to optimize for
135 size instead of speed. */
136 #define REG_FREQ_MAX 1000
138 /* Compute register frequency from the BB frequency. When optimizing for size,
139 or profile driven feedback is available and the function is never executed,
140 frequency is always equivalent. Otherwise rescale the basic block
142 #define REG_FREQ_FROM_BB(bb) (optimize_size \
143 || (flag_branch_probabilities \
144 && !ENTRY_BLOCK_PTR->count) \
146 : ((bb)->frequency * REG_FREQ_MAX / BB_FREQ_MAX)\
147 ? ((bb)->frequency * REG_FREQ_MAX / BB_FREQ_MAX)\
150 /* Indexed by N, gives number of insns in which register N dies.
151 Note that if register N is live around loops, it can die
152 in transitions between basic blocks, and that is not counted here.
153 So this is only a reliable indicator of how many regions of life there are
154 for registers that are contained in one basic block. */
156 #define REG_N_DEATHS(N) (reg_info_p[N].deaths)
158 /* Get the number of consecutive words required to hold pseudo-reg N. */
160 #define PSEUDO_REGNO_SIZE(N) \
161 ((GET_MODE_SIZE (PSEUDO_REGNO_MODE (N)) + UNITS_PER_WORD - 1) \
164 /* Get the number of bytes required to hold pseudo-reg N. */
166 #define PSEUDO_REGNO_BYTES(N) \
167 GET_MODE_SIZE (PSEUDO_REGNO_MODE (N))
169 /* Get the machine mode of pseudo-reg N. */
171 #define PSEUDO_REGNO_MODE(N) GET_MODE (regno_reg_rtx[N])
173 /* Indexed by N, gives number of CALL_INSNS across which (REG n) is live. */
175 #define REG_N_CALLS_CROSSED(N) (reg_info_p[N].calls_crossed)
176 #define REG_FREQ_CALLS_CROSSED(N) (reg_info_p[N].freq_calls_crossed)
178 /* Indexed by N, gives number of CALL_INSNS that may throw, across which
181 #define REG_N_THROWING_CALLS_CROSSED(N) (reg_info_p[N].throw_calls_crossed)
183 /* Total number of instructions at which (REG n) is live. The larger
184 this is, the less priority (REG n) gets for allocation in a hard
185 register (in global-alloc). This is set in df-problems.c whenever
186 register info is requested and remains valid for the rest of the
187 compilation of the function; it is used to control register
190 local-alloc.c may alter this number to change the priority.
192 Negative values are special.
193 -1 is used to mark a pseudo reg which has a constant or memory equivalent
194 and is used infrequently enough that it should not get a hard register.
195 -2 is used to mark a pseudo reg for a parameter, when a frame pointer
196 is not required. global.c makes an allocno for this but does
197 not try to assign a hard register to it. */
199 #define REG_LIVE_LENGTH(N) (reg_info_p[N].live_length)
201 /* Indexed by n, gives number of basic block that (REG n) is used in.
202 If the value is REG_BLOCK_GLOBAL (-1),
203 it means (REG n) is used in more than one basic block.
204 REG_BLOCK_UNKNOWN (0) means it hasn't been seen yet so we don't know.
205 This information remains valid for the rest of the compilation
206 of the current function; it is used to control register allocation. */
208 #define REG_BLOCK_UNKNOWN 0
209 #define REG_BLOCK_GLOBAL -1
211 #define REG_BASIC_BLOCK(N) (reg_info_p[N].basic_block)
213 /* Vector of substitutions of register numbers,
214 used to map pseudo regs into hardware regs.
216 This can't be folded into reg_n_info without changing all of the
217 machine dependent directories, since the reload functions
218 in the machine dependent files access it. */
220 extern short *reg_renumber;
222 /* Vector indexed by machine mode saying whether there are regs of that mode. */
224 extern bool have_regs_of_mode [MAX_MACHINE_MODE];
226 /* For each hard register, the widest mode object that it can contain.
227 This will be a MODE_INT mode if the register can hold integers. Otherwise
228 it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the
231 extern enum machine_mode reg_raw_mode[FIRST_PSEUDO_REGISTER];
233 /* Flag set by local-alloc or global-alloc if they decide to allocate
234 something in a call-clobbered register. */
236 extern int caller_save_needed;
238 /* Predicate to decide whether to give a hard reg to a pseudo which
239 is referenced REFS times and would need to be saved and restored
240 around a call CALLS times. */
242 #ifndef CALLER_SAVE_PROFITABLE
243 #define CALLER_SAVE_PROFITABLE(REFS, CALLS) (4 * (CALLS) < (REFS))
246 /* On most machines a register class is likely to be spilled if it
247 only has one register. */
248 #ifndef CLASS_LIKELY_SPILLED_P
249 #define CLASS_LIKELY_SPILLED_P(CLASS) (reg_class_size[(int) (CLASS)] == 1)
252 /* Select a register mode required for caller save of hard regno REGNO. */
253 #ifndef HARD_REGNO_CALLER_SAVE_MODE
254 #define HARD_REGNO_CALLER_SAVE_MODE(REGNO, NREGS, MODE) \
255 choose_hard_reg_mode (REGNO, NREGS, false)
258 /* Registers that get partially clobbered by a call in a given mode.
259 These must not be call used registers. */
260 #ifndef HARD_REGNO_CALL_PART_CLOBBERED
261 #define HARD_REGNO_CALL_PART_CLOBBERED(REGNO, MODE) 0
264 /* 1 if the corresponding class does contain register of given
266 extern char contains_reg_of_mode [N_REG_CLASSES] [MAX_MACHINE_MODE];
268 typedef unsigned short move_table[N_REG_CLASSES];
270 /* Maximum cost of moving from a register in one class to a register
272 extern move_table *move_cost[MAX_MACHINE_MODE];
274 /* Specify number of hard registers given machine mode occupy. */
275 extern unsigned char hard_regno_nregs[FIRST_PSEUDO_REGISTER][MAX_MACHINE_MODE];
277 /* Similar, but here we don't have to move if the first index is a
278 subset of the second so in that case the cost is zero. */
279 extern move_table *may_move_in_cost[MAX_MACHINE_MODE];
281 /* Similar, but here we don't have to move if the first index is a
282 superset of the second so in that case the cost is zero. */
283 extern move_table *may_move_out_cost[MAX_MACHINE_MODE];
285 /* Return an exclusive upper bound on the registers occupied by hard
286 register (reg:MODE REGNO). */
288 static inline unsigned int
289 end_hard_regno (enum machine_mode mode, unsigned int regno)
291 return regno + hard_regno_nregs[regno][(int) mode];
294 /* Likewise for hard register X. */
296 #define END_HARD_REGNO(X) end_hard_regno (GET_MODE (X), REGNO (X))
298 /* Likewise for hard or pseudo register X. */
300 #define END_REGNO(X) (HARD_REGISTER_P (X) ? END_HARD_REGNO (X) : REGNO (X) + 1)
302 /* Add to REGS all the registers required to store a value of mode MODE
303 in register REGNO. */
306 add_to_hard_reg_set (HARD_REG_SET *regs, enum machine_mode mode,
309 unsigned int end_regno;
311 end_regno = end_hard_regno (mode, regno);
313 SET_HARD_REG_BIT (*regs, regno);
314 while (++regno < end_regno);
317 /* Likewise, but remove the registers. */
320 remove_from_hard_reg_set (HARD_REG_SET *regs, enum machine_mode mode,
323 unsigned int end_regno;
325 end_regno = end_hard_regno (mode, regno);
327 CLEAR_HARD_REG_BIT (*regs, regno);
328 while (++regno < end_regno);
331 /* Return true if REGS contains the whole of (reg:MODE REGNO). */
334 in_hard_reg_set_p (const HARD_REG_SET regs, enum machine_mode mode,
337 unsigned int end_regno;
339 if (!TEST_HARD_REG_BIT (regs, regno))
342 end_regno = end_hard_regno (mode, regno);
343 while (++regno < end_regno)
344 if (!TEST_HARD_REG_BIT (regs, regno))
350 /* Return true if (reg:MODE REGNO) includes an element of REGS. */
353 overlaps_hard_reg_set_p (const HARD_REG_SET regs, enum machine_mode mode,
356 unsigned int end_regno;
358 if (TEST_HARD_REG_BIT (regs, regno))
361 end_regno = end_hard_regno (mode, regno);
362 while (++regno < end_regno)
363 if (TEST_HARD_REG_BIT (regs, regno))
369 #endif /* GCC_REGS_H */