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 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, 51 Franklin Street, Fifth Floor, 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 /* REG_N_REFS and REG_N_SETS are initialized by a call to
50 regstat_init_n_sets_and_refs from the current values of
51 DF_REG_DEF_COUNT and DF_REG_USE_COUNT. REG_N_REFS and REG_N_SETS
52 should only be used if a pass need to change these values in some
53 magical way or or the pass needs to have accurate values for these
54 and is not using incremental df scanning.
56 At the end of a pass that uses REG_N_REFS and REG_N_SETS, a call
57 should be made to regstat_free_n_sets_and_refs.
59 Local alloc seems to play pretty loose with these values.
60 REG_N_REFS is set to 0 if the register is used in an asm.
61 Furthermore, local_alloc calls regclass to hack both REG_N_REFS and
62 REG_N_SETS for three address insns. Other passes seem to have
63 other special values. */
67 /* Structure to hold values for REG_N_SETS (i) and REG_N_REFS (i). */
69 struct regstat_n_sets_and_refs_t
71 int sets; /* # of times (REG n) is set */
72 int refs; /* # of times (REG n) is used or set */
75 extern struct regstat_n_sets_and_refs_t *regstat_n_sets_and_refs;
77 /* Indexed by n, gives number of times (REG n) is used or set. */
81 return regstat_n_sets_and_refs[regno].refs;
84 /* Indexed by n, gives number of times (REG n) is used or set. */
85 #define SET_REG_N_REFS(N,V) (regstat_n_sets_and_refs[N].refs = V)
86 #define INC_REG_N_REFS(N,V) (regstat_n_sets_and_refs[N].refs += V)
88 /* Indexed by n, gives number of times (REG n) is set. */
90 REG_N_SETS (int regno)
92 return regstat_n_sets_and_refs[regno].sets;
95 /* Indexed by n, gives number of times (REG n) is set. */
96 #define SET_REG_N_SETS(N,V) (regstat_n_sets_and_refs[N].sets = V)
97 #define INC_REG_N_SETS(N,V) (regstat_n_sets_and_refs[N].sets += V)
100 /* Functions defined in reg-stat.c. */
101 extern void regstat_init_n_sets_and_refs (void);
102 extern void regstat_free_n_sets_and_refs (void);
103 extern void regstat_compute_ri (void);
104 extern void regstat_free_ri (void);
105 extern bitmap regstat_get_setjmp_crosses (void);
106 extern void regstat_compute_calls_crossed (void);
107 extern void regstat_free_calls_crossed (void);
110 /* Register information indexed by register number. This structure is
111 initialized by calling regstat_compute_ri and is destroyed by
112 calling regstat_free_ri. */
115 int freq; /* # estimated frequency (REG n) is used or set */
116 int deaths; /* # of times (REG n) dies */
117 int live_length; /* # of instructions (REG n) is live */
118 int calls_crossed; /* # of calls (REG n) is live across */
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 varries 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)
177 /* Indexed by N, gives number of CALL_INSNS that may throw, across which
180 #define REG_N_THROWING_CALLS_CROSSED(N) (reg_info_p[N].throw_calls_crossed)
182 /* Total number of instructions at which (REG n) is live. The larger
183 this is, the less priority (REG n) gets for allocation in a hard
184 register (in global-alloc). This is set in df-problems.c whenever
185 register info is requested and remains valid for the rest of the
186 compilation of the function; it is used to control register
189 local-alloc.c may alter this number to change the priority.
191 Negative values are special.
192 -1 is used to mark a pseudo reg which has a constant or memory equivalent
193 and is used infrequently enough that it should not get a hard register.
194 -2 is used to mark a pseudo reg for a parameter, when a frame pointer
195 is not required. global.c makes an allocno for this but does
196 not try to assign a hard register to it. */
198 #define REG_LIVE_LENGTH(N) (reg_info_p[N].live_length)
200 /* Indexed by n, gives number of basic block that (REG n) is used in.
201 If the value is REG_BLOCK_GLOBAL (-1),
202 it means (REG n) is used in more than one basic block.
203 REG_BLOCK_UNKNOWN (0) means it hasn't been seen yet so we don't know.
204 This information remains valid for the rest of the compilation
205 of the current function; it is used to control register allocation. */
207 #define REG_BLOCK_UNKNOWN 0
208 #define REG_BLOCK_GLOBAL -1
210 #define REG_BASIC_BLOCK(N) (reg_info_p[N].basic_block)
212 /* Vector of substitutions of register numbers,
213 used to map pseudo regs into hardware regs.
215 This can't be folded into reg_n_info without changing all of the
216 machine dependent directories, since the reload functions
217 in the machine dependent files access it. */
219 extern short *reg_renumber;
221 /* Vector indexed by machine mode saying whether there are regs of that mode. */
223 extern bool have_regs_of_mode [MAX_MACHINE_MODE];
225 /* For each hard register, the widest mode object that it can contain.
226 This will be a MODE_INT mode if the register can hold integers. Otherwise
227 it will be a MODE_FLOAT or a MODE_CC mode, whichever is valid for the
230 extern enum machine_mode reg_raw_mode[FIRST_PSEUDO_REGISTER];
232 /* Flag set by local-alloc or global-alloc if they decide to allocate
233 something in a call-clobbered register. */
235 extern int caller_save_needed;
237 /* Predicate to decide whether to give a hard reg to a pseudo which
238 is referenced REFS times and would need to be saved and restored
239 around a call CALLS times. */
241 #ifndef CALLER_SAVE_PROFITABLE
242 #define CALLER_SAVE_PROFITABLE(REFS, CALLS) (4 * (CALLS) < (REFS))
245 /* On most machines a register class is likely to be spilled if it
246 only has one register. */
247 #ifndef CLASS_LIKELY_SPILLED_P
248 #define CLASS_LIKELY_SPILLED_P(CLASS) (reg_class_size[(int) (CLASS)] == 1)
251 /* Select a register mode required for caller save of hard regno REGNO. */
252 #ifndef HARD_REGNO_CALLER_SAVE_MODE
253 #define HARD_REGNO_CALLER_SAVE_MODE(REGNO, NREGS, MODE) \
254 choose_hard_reg_mode (REGNO, NREGS, false)
257 /* Registers that get partially clobbered by a call in a given mode.
258 These must not be call used registers. */
259 #ifndef HARD_REGNO_CALL_PART_CLOBBERED
260 #define HARD_REGNO_CALL_PART_CLOBBERED(REGNO, MODE) 0
263 /* Specify number of hard registers given machine mode occupy. */
264 extern unsigned char hard_regno_nregs[FIRST_PSEUDO_REGISTER][MAX_MACHINE_MODE];
266 /* Return an exclusive upper bound on the registers occupied by hard
267 register (reg:MODE REGNO). */
269 static inline unsigned int
270 end_hard_regno (enum machine_mode mode, unsigned int regno)
272 return regno + hard_regno_nregs[regno][(int) mode];
275 /* Likewise for hard register X. */
277 #define END_HARD_REGNO(X) end_hard_regno (GET_MODE (X), REGNO (X))
279 /* Likewise for hard or pseudo register X. */
281 #define END_REGNO(X) (HARD_REGISTER_P (X) ? END_HARD_REGNO (X) : REGNO (X) + 1)
283 /* Add to REGS all the registers required to store a value of mode MODE
284 in register REGNO. */
287 add_to_hard_reg_set (HARD_REG_SET *regs, enum machine_mode mode,
290 unsigned int end_regno;
292 end_regno = end_hard_regno (mode, regno);
294 SET_HARD_REG_BIT (*regs, regno);
295 while (++regno < end_regno);
298 /* Likewise, but remove the registers. */
301 remove_from_hard_reg_set (HARD_REG_SET *regs, enum machine_mode mode,
304 unsigned int end_regno;
306 end_regno = end_hard_regno (mode, regno);
308 CLEAR_HARD_REG_BIT (*regs, regno);
309 while (++regno < end_regno);
312 /* Return true if REGS contains the whole of (reg:MODE REGNO). */
315 in_hard_reg_set_p (const HARD_REG_SET regs, enum machine_mode mode,
318 unsigned int end_regno;
320 if (!TEST_HARD_REG_BIT (regs, regno))
323 end_regno = end_hard_regno (mode, regno);
324 while (++regno < end_regno)
325 if (!TEST_HARD_REG_BIT (regs, regno))
331 /* Return true if (reg:MODE REGNO) includes an element of REGS. */
334 overlaps_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 #endif /* GCC_REGS_H */