* tree.c (make_node): Set TREE_SIDE_EFFECTS for expressions that
[official-gcc.git] / gcc / reload.h
blob5371362b1c021a777e2407aa7426451b921a1e39
1 /* Communication between reload.c and reload1.c.
2 Copyright (C) 1987, 91-95, 97, 1998 Free Software Foundation, Inc.
4 This file is part of GNU CC.
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.
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.
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
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
22 /* If secondary reloads are the same for inputs and outputs, define those
23 macros here. */
25 #ifdef SECONDARY_RELOAD_CLASS
26 #define SECONDARY_INPUT_RELOAD_CLASS(CLASS, MODE, X) \
27 SECONDARY_RELOAD_CLASS (CLASS, MODE, X)
28 #define SECONDARY_OUTPUT_RELOAD_CLASS(CLASS, MODE, X) \
29 SECONDARY_RELOAD_CLASS (CLASS, MODE, X)
30 #endif
32 /* If either macro is defined, show that we need secondary reloads. */
33 #if defined(SECONDARY_INPUT_RELOAD_CLASS) || defined(SECONDARY_OUTPUT_RELOAD_CLASS)
34 #define HAVE_SECONDARY_RELOADS
35 #endif
37 /* If MEMORY_MOVE_COST isn't defined, give it a default here. */
38 #ifndef MEMORY_MOVE_COST
39 #ifdef HAVE_SECONDARY_RELOADS
40 #define MEMORY_MOVE_COST(MODE,CLASS,IN) \
41 (4 + memory_move_secondary_cost ((MODE), (CLASS), (IN)))
42 #else
43 #define MEMORY_MOVE_COST(MODE,CLASS,IN) 4
44 #endif
45 #endif
46 extern int memory_move_secondary_cost PROTO ((enum machine_mode, enum reg_class, int));
48 /* Maximum number of reloads we can need. */
49 #define MAX_RELOADS (2 * MAX_RECOG_OPERANDS * (MAX_REGS_PER_ADDRESS + 1))
51 /* Encode the usage of a reload. The following codes are supported:
53 RELOAD_FOR_INPUT reload of an input operand
54 RELOAD_FOR_OUTPUT likewise, for output
55 RELOAD_FOR_INSN a reload that must not conflict with anything
56 used in the insn, but may conflict with
57 something used before or after the insn
58 RELOAD_FOR_INPUT_ADDRESS reload for parts of the address of an object
59 that is an input reload
60 RELOAD_FOR_INPADDR_ADDRESS reload needed for RELOAD_FOR_INPUT_ADDRESS
61 RELOAD_FOR_OUTPUT_ADDRESS like RELOAD_FOR INPUT_ADDRESS, for output
62 RELOAD_FOR_OUTADDR_ADDRESS reload needed for RELOAD_FOR_OUTPUT_ADDRESS
63 RELOAD_FOR_OPERAND_ADDRESS reload for the address of a non-reloaded
64 operand; these don't conflict with
65 any other addresses.
66 RELOAD_FOR_OPADDR_ADDR reload needed for RELOAD_FOR_OPERAND_ADDRESS
67 reloads; usually secondary reloads
68 RELOAD_OTHER none of the above, usually multiple uses
69 RELOAD_FOR_OTHER_ADDRESS reload for part of the address of an input
70 that is marked RELOAD_OTHER.
72 This used to be "enum reload_when_needed" but some debuggers have trouble
73 with an enum tag and variable of the same name. */
75 enum reload_type
77 RELOAD_FOR_INPUT, RELOAD_FOR_OUTPUT, RELOAD_FOR_INSN,
78 RELOAD_FOR_INPUT_ADDRESS, RELOAD_FOR_INPADDR_ADDRESS,
79 RELOAD_FOR_OUTPUT_ADDRESS, RELOAD_FOR_OUTADDR_ADDRESS,
80 RELOAD_FOR_OPERAND_ADDRESS, RELOAD_FOR_OPADDR_ADDR,
81 RELOAD_OTHER, RELOAD_FOR_OTHER_ADDRESS
84 #ifdef MAX_INSN_CODE
85 /* Each reload is recorded with a structure like this. */
86 struct reload
88 /* The value to reload from */
89 rtx in;
90 /* Where to store reload-reg afterward if nec (often the same as
91 reload_in) */
92 rtx out;
94 /* The class of registers to reload into. */
95 enum reg_class class;
97 /* The mode this operand should have when reloaded, on input. */
98 enum machine_mode inmode;
99 /* The mode this operand should have when reloaded, on output. */
100 enum machine_mode outmode;
102 /* Positive amount to increment or decrement by if
103 reload_in is a PRE_DEC, PRE_INC, POST_DEC, POST_INC.
104 Ignored otherwise (don't assume it is zero). */
105 int inc;
106 /* A reg for which reload_in is the equivalent.
107 If reload_in is a symbol_ref which came from
108 reg_equiv_constant, then this is the pseudo
109 which has that symbol_ref as equivalent. */
110 rtx in_reg;
111 rtx out_reg;
113 /* Used in find_reload_regs to record the allocated register. */
114 int regno;
115 /* This is the register to reload into. If it is zero when `find_reloads'
116 returns, you must find a suitable register in the class specified by
117 reload_reg_class, and store here an rtx for that register with mode from
118 reload_inmode or reload_outmode. */
119 rtx reg_rtx;
120 /* The operand number being reloaded. This is used to group related reloads
121 and need not always be equal to the actual operand number in the insn,
122 though it current will be; for in-out operands, it is one of the two
123 operand numbers. */
124 int opnum;
126 /* Gives the reload number of a secondary input reload, when needed;
127 otherwise -1. */
128 int secondary_in_reload;
129 /* Gives the reload number of a secondary output reload, when needed;
130 otherwise -1. */
131 int secondary_out_reload;
132 /* If a secondary input reload is required, gives the INSN_CODE that uses the
133 secondary reload as a scratch register, or CODE_FOR_nothing if the
134 secondary reload register is to be an intermediate register. */
135 enum insn_code secondary_in_icode;
136 /* Likewise, for a secondary output reload. */
137 enum insn_code secondary_out_icode;
139 /* Classifies reload as needed either for addressing an input reload,
140 addressing an output, for addressing a non-reloaded mem ref, or for
141 unspecified purposes (i.e., more than one of the above). */
142 enum reload_type when_needed;
144 /* Nonzero for an optional reload. Optional reloads are ignored unless the
145 value is already sitting in a register. */
146 unsigned int optional:1;
147 /* nonzero if this reload shouldn't be combined with another reload. */
148 unsigned int nocombine:1;
149 /* Nonzero if this is a secondary register for one or more reloads. */
150 unsigned int secondary_p:1;
151 /* Nonzero if this reload must use a register not already allocated to a
152 group. */
153 unsigned int nongroup:1;
156 extern struct reload rld[MAX_RELOADS];
157 extern int n_reloads;
158 #endif
160 extern rtx *reg_equiv_constant;
161 extern rtx *reg_equiv_memory_loc;
162 extern rtx *reg_equiv_address;
163 extern rtx *reg_equiv_mem;
165 /* All the "earlyclobber" operands of the current insn
166 are recorded here. */
167 extern int n_earlyclobbers;
168 extern rtx reload_earlyclobbers[MAX_RECOG_OPERANDS];
170 /* Save the number of operands. */
171 extern int reload_n_operands;
173 /* First uid used by insns created by reload in this function.
174 Used in find_equiv_reg. */
175 extern int reload_first_uid;
177 /* Nonzero if indirect addressing is supported when the innermost MEM is
178 of the form (MEM (SYMBOL_REF sym)). It is assumed that the level to
179 which these are valid is the same as spill_indirect_levels, above. */
181 extern char indirect_symref_ok;
183 /* Nonzero if an address (plus (reg frame_pointer) (reg ...)) is valid. */
184 extern char double_reg_address_ok;
186 extern int num_not_at_initial_offset;
188 #ifdef MAX_INSN_CODE
189 /* These arrays record the insn_code of insns that may be needed to
190 perform input and output reloads of special objects. They provide a
191 place to pass a scratch register. */
192 extern enum insn_code reload_in_optab[];
193 extern enum insn_code reload_out_optab[];
194 #endif
196 struct needs
198 /* [0] is normal, [1] is nongroup. */
199 short regs[2][N_REG_CLASSES];
200 short groups[N_REG_CLASSES];
203 #if defined SET_HARD_REG_BIT && defined CLEAR_REG_SET
204 /* This structure describes instructions which are relevant for reload.
205 Apart from all regular insns, this also includes CODE_LABELs, since they
206 must be examined for register elimination. */
207 struct insn_chain
209 /* Links to the neighbour instructions. */
210 struct insn_chain *next, *prev;
212 /* Link through a chains set up by calculate_needs_all_insns, containing
213 all insns that need reloading. */
214 struct insn_chain *next_need_reload;
216 /* The basic block this insn is in. */
217 int block;
218 /* The rtx of the insn. */
219 rtx insn;
220 /* Register life information: record all live hard registers, and all
221 live pseudos that have a hard register.
222 This information is recorded for the point immediately before the insn
223 (in live_before), and for the point within the insn at which all
224 outputs have just been written to (in live_after). */
225 regset live_before;
226 regset live_after;
228 /* For each class, size of group of consecutive regs
229 that is needed for the reloads of this class. */
230 char group_size[N_REG_CLASSES];
231 /* For each class, the machine mode which requires consecutive
232 groups of regs of that class.
233 If two different modes ever require groups of one class,
234 they must be the same size and equally restrictive for that class,
235 otherwise we can't handle the complexity. */
236 enum machine_mode group_mode[N_REG_CLASSES];
238 /* Indicates if a register was counted against the need for
239 groups. 0 means it can count against max_nongroup instead. */
240 HARD_REG_SET counted_for_groups;
242 /* Indicates if a register was counted against the need for
243 non-groups. 0 means it can become part of a new group.
244 During choose_reload_regs, 1 here means don't use this reg
245 as part of a group, even if it seems to be otherwise ok. */
246 HARD_REG_SET counted_for_nongroups;
248 /* Indicates which registers have already been used for spills. */
249 HARD_REG_SET used_spill_regs;
251 /* Describe the needs for reload registers of this insn. */
252 struct needs need;
254 /* Nonzero if find_reloads said the insn requires reloading. */
255 unsigned int need_reload:1;
256 /* Nonzero if find_reloads needs to be run during reload_as_needed to
257 perform modifications on any operands. */
258 unsigned int need_operand_change:1;
259 /* Nonzero if eliminate_regs_in_insn said it requires eliminations. */
260 unsigned int need_elim:1;
261 /* Nonzero if this insn was inserted by perform_caller_saves. */
262 unsigned int is_caller_save_insn:1;
265 /* A chain of insn_chain structures to describe all non-note insns in
266 a function. */
267 extern struct insn_chain *reload_insn_chain;
269 /* Allocate a new insn_chain structure. */
270 extern struct insn_chain *new_insn_chain PROTO((void));
272 extern void compute_use_by_pseudos PROTO((HARD_REG_SET *, regset));
273 #endif
275 /* Functions from reload.c: */
277 /* Return a memory location that will be used to copy X in mode MODE.
278 If we haven't already made a location for this mode in this insn,
279 call find_reloads_address on the location being returned. */
280 extern rtx get_secondary_mem PROTO((rtx, enum machine_mode,
281 int, enum reload_type));
283 /* Clear any secondary memory locations we've made. */
284 extern void clear_secondary_mem PROTO((void));
286 /* Transfer all replacements that used to be in reload FROM to be in
287 reload TO. */
288 extern void transfer_replacements PROTO((int, int));
290 /* IN_RTX is the value loaded by a reload that we now decided to inherit,
291 or a subpart of it. If we have any replacements registered for IN_RTX,
292 chancel the reloads that were supposed to load them.
293 Return non-zero if we chanceled any reloads. */
294 extern int remove_address_replacements PROTO((rtx in_rtx));
296 /* Like rtx_equal_p except that it allows a REG and a SUBREG to match
297 if they are the same hard reg, and has special hacks for
298 autoincrement and autodecrement. */
299 extern int operands_match_p PROTO((rtx, rtx));
301 /* Return 1 if altering OP will not modify the value of CLOBBER. */
302 extern int safe_from_earlyclobber PROTO((rtx, rtx));
304 /* Search the body of INSN for values that need reloading and record them
305 with push_reload. REPLACE nonzero means record also where the values occur
306 so that subst_reloads can be used. */
307 extern int find_reloads PROTO((rtx, int, int, int, short *));
309 /* Compute the sum of X and Y, making canonicalizations assumed in an
310 address, namely: sum constant integers, surround the sum of two
311 constants with a CONST, put the constant as the second operand, and
312 group the constant on the outermost sum. */
313 extern rtx form_sum PROTO((rtx, rtx));
315 /* Substitute into the current INSN the registers into which we have reloaded
316 the things that need reloading. */
317 extern void subst_reloads PROTO((void));
319 /* Make a copy of any replacements being done into X and move those copies
320 to locations in Y, a copy of X. We only look at the highest level of
321 the RTL. */
322 extern void copy_replacements PROTO((rtx, rtx));
324 /* Change any replacements being done to *X to be done to *Y */
325 extern void move_replacements PROTO((rtx *x, rtx *y));
327 /* If LOC was scheduled to be replaced by something, return the replacement.
328 Otherwise, return *LOC. */
329 extern rtx find_replacement PROTO((rtx *));
331 /* Return nonzero if register in range [REGNO, ENDREGNO)
332 appears either explicitly or implicitly in X
333 other than being stored into. */
334 extern int refers_to_regno_for_reload_p PROTO((int, int, rtx, rtx *));
336 /* Nonzero if modifying X will affect IN. */
337 extern int reg_overlap_mentioned_for_reload_p PROTO((rtx, rtx));
339 /* Return nonzero if anything in X contains a MEM. Look also for pseudo
340 registers. */
341 extern int refers_to_mem_for_reload_p PROTO((rtx));
343 /* Check the insns before INSN to see if there is a suitable register
344 containing the same value as GOAL. */
345 extern rtx find_equiv_reg PROTO((rtx, rtx, enum reg_class, int, short *,
346 int, enum machine_mode));
348 /* Return 1 if register REGNO is the subject of a clobber in insn INSN. */
349 extern int regno_clobbered_p PROTO((int, rtx));
351 /* Functions in reload1.c: */
353 extern int reloads_conflict PROTO ((int, int));
355 int count_occurrences PROTO((rtx, rtx));
357 /* Initialize the reload pass once per compilation. */
358 extern void init_reload PROTO((void));
360 /* The reload pass itself. */
361 extern int reload PROTO((rtx, int, FILE *));
363 /* Mark the slots in regs_ever_live for the hard regs
364 used by pseudo-reg number REGNO. */
365 extern void mark_home_live PROTO((int));
367 /* Scan X and replace any eliminable registers (such as fp) with a
368 replacement (such as sp), plus an offset. */
369 extern rtx eliminate_regs PROTO((rtx, enum machine_mode, rtx));
371 /* Emit code to perform a reload from IN (which may be a reload register) to
372 OUT (which may also be a reload register). IN or OUT is from operand
373 OPNUM with reload type TYPE. */
374 extern rtx gen_reload PROTO((rtx, rtx, int, enum reload_type));
376 /* Deallocate the reload register used by reload number R. */
377 extern void deallocate_reload_reg PROTO((int r));
379 /* Functions in caller-save.c: */
381 /* Initialize for caller-save. */
382 extern void init_caller_save PROTO((void));
384 /* Initialize save areas by showing that we haven't allocated any yet. */
385 extern void init_save_areas PROTO((void));
387 /* Allocate save areas for any hard registers that might need saving. */
388 extern void setup_save_areas PROTO((void));
390 /* Find the places where hard regs are live across calls and save them. */
391 extern void save_call_clobbered_regs PROTO((void));
393 /* Replace (subreg (reg)) with the appropriate (reg) for any operands. */
394 extern void cleanup_subreg_operands PROTO ((rtx));