gcc/reload.h

   1 /* Communication between reload.c and reload1.c.
   2    Copyright (C) 1987, 1991, 1992, 1993, 1994, 1995, 1997, 1998,
   3    1999, 2000, 2001, 2003, 2004 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   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
  10 version.
  11
  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
  15 for more details.
  16
  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
  20 02111-1307, USA.  */
  21
  22
  23 /* If secondary reloads are the same for inputs and outputs, define those
  24    macros here.  */
  25
  26 #ifdef SECONDARY_RELOAD_CLASS
  27 #define SECONDARY_INPUT_RELOAD_CLASS(CLASS, MODE, X) \
  28   SECONDARY_RELOAD_CLASS (CLASS, MODE, X)
  29 #define SECONDARY_OUTPUT_RELOAD_CLASS(CLASS, MODE, X) \
  30   SECONDARY_RELOAD_CLASS (CLASS, MODE, X)
  31 #endif
  32
  33 /* If either macro is defined, show that we need secondary reloads.  */
  34 #if defined(SECONDARY_INPUT_RELOAD_CLASS) || defined(SECONDARY_OUTPUT_RELOAD_CLASS)
  35 #define HAVE_SECONDARY_RELOADS
  36 #endif
  37
  38 /* If MEMORY_MOVE_COST isn't defined, give it a default here.  */
  39 #ifndef MEMORY_MOVE_COST
  40 #ifdef HAVE_SECONDARY_RELOADS
  41 #define MEMORY_MOVE_COST(MODE,CLASS,IN) \
  42   (4 + memory_move_secondary_cost ((MODE), (CLASS), (IN)))
  43 #else
  44 #define MEMORY_MOVE_COST(MODE,CLASS,IN) 4
  45 #endif
  46 #endif
  47 extern int memory_move_secondary_cost (enum machine_mode, enum reg_class, int);
  48
  49 /* Maximum number of reloads we can need.  */
  50 #define MAX_RELOADS (2 * MAX_RECOG_OPERANDS * (MAX_REGS_PER_ADDRESS + 1))
  51
  52 /* Encode the usage of a reload.  The following codes are supported:
  53
  54    RELOAD_FOR_INPUT             reload of an input operand
  55    RELOAD_FOR_OUTPUT            likewise, for output
  56    RELOAD_FOR_INSN              a reload that must not conflict with anything
  57                                 used in the insn, but may conflict with
  58                                 something used before or after the insn
  59    RELOAD_FOR_INPUT_ADDRESS     reload for parts of the address of an object
  60                                 that is an input reload
  61    RELOAD_FOR_INPADDR_ADDRESS   reload needed for RELOAD_FOR_INPUT_ADDRESS
  62    RELOAD_FOR_OUTPUT_ADDRESS    like RELOAD_FOR INPUT_ADDRESS, for output
  63    RELOAD_FOR_OUTADDR_ADDRESS   reload needed for RELOAD_FOR_OUTPUT_ADDRESS
  64    RELOAD_FOR_OPERAND_ADDRESS   reload for the address of a non-reloaded
  65                                 operand; these don't conflict with
  66                                 any other addresses.
  67    RELOAD_FOR_OPADDR_ADDR       reload needed for RELOAD_FOR_OPERAND_ADDRESS
  68                                 reloads; usually secondary reloads
  69    RELOAD_OTHER                 none of the above, usually multiple uses
  70    RELOAD_FOR_OTHER_ADDRESS     reload for part of the address of an input
  71                                 that is marked RELOAD_OTHER.
  72
  73    This used to be "enum reload_when_needed" but some debuggers have trouble
  74    with an enum tag and variable of the same name.  */
  75
  76 enum reload_type
  77 {
  78   RELOAD_FOR_INPUT, RELOAD_FOR_OUTPUT, RELOAD_FOR_INSN,
  79   RELOAD_FOR_INPUT_ADDRESS, RELOAD_FOR_INPADDR_ADDRESS,
  80   RELOAD_FOR_OUTPUT_ADDRESS, RELOAD_FOR_OUTADDR_ADDRESS,
  81   RELOAD_FOR_OPERAND_ADDRESS, RELOAD_FOR_OPADDR_ADDR,
  82   RELOAD_OTHER, RELOAD_FOR_OTHER_ADDRESS
  83 };
  84
  85 #ifdef GCC_INSN_CODES_H
  86 /* Each reload is recorded with a structure like this.  */
  87 struct reload
  88 {
  89   /* The value to reload from */
  90   rtx in;
  91   /* Where to store reload-reg afterward if nec (often the same as
  92      reload_in)  */
  93   rtx out;
  94
  95   /* The class of registers to reload into.  */
  96   enum reg_class class;
  97
  98   /* The mode this operand should have when reloaded, on input.  */
  99   enum machine_mode inmode;
 100   /* The mode this operand should have when reloaded, on output.  */
 101   enum machine_mode outmode;
 102
 103   /* The mode of the reload register.  */
 104   enum machine_mode mode;
 105
 106   /* the largest number of registers this reload will require.  */
 107   unsigned int nregs;
 108
 109   /* Positive amount to increment or decrement by if
 110      reload_in is a PRE_DEC, PRE_INC, POST_DEC, POST_INC.
 111      Ignored otherwise (don't assume it is zero).  */
 112   int inc;
 113   /* A reg for which reload_in is the equivalent.
 114      If reload_in is a symbol_ref which came from
 115      reg_equiv_constant, then this is the pseudo
 116      which has that symbol_ref as equivalent.  */
 117   rtx in_reg;
 118   rtx out_reg;
 119
 120   /* Used in find_reload_regs to record the allocated register.  */
 121   int regno;
 122   /* This is the register to reload into.  If it is zero when `find_reloads'
 123      returns, you must find a suitable register in the class specified by
 124      reload_reg_class, and store here an rtx for that register with mode from
 125      reload_inmode or reload_outmode.  */
 126   rtx reg_rtx;
 127   /* The operand number being reloaded.  This is used to group related reloads
 128      and need not always be equal to the actual operand number in the insn,
 129      though it current will be; for in-out operands, it is one of the two
 130      operand numbers.  */
 131   int opnum;
 132
 133   /* Gives the reload number of a secondary input reload, when needed;
 134      otherwise -1.  */
 135   int secondary_in_reload;
 136   /* Gives the reload number of a secondary output reload, when needed;
 137      otherwise -1.  */
 138   int secondary_out_reload;
 139   /* If a secondary input reload is required, gives the INSN_CODE that uses the
 140      secondary reload as a scratch register, or CODE_FOR_nothing if the
 141      secondary reload register is to be an intermediate register.  */
 142   enum insn_code secondary_in_icode;
 143   /* Likewise, for a secondary output reload.  */
 144   enum insn_code secondary_out_icode;
 145
 146   /* Classifies reload as needed either for addressing an input reload,
 147      addressing an output, for addressing a non-reloaded mem ref, or for
 148      unspecified purposes (i.e., more than one of the above).  */
 149   enum reload_type when_needed;
 150
 151   /* Nonzero for an optional reload.  Optional reloads are ignored unless the
 152      value is already sitting in a register.  */
 153   unsigned int optional:1;
 154   /* nonzero if this reload shouldn't be combined with another reload.  */
 155   unsigned int nocombine:1;
 156   /* Nonzero if this is a secondary register for one or more reloads.  */
 157   unsigned int secondary_p:1;
 158   /* Nonzero if this reload must use a register not already allocated to a
 159      group.  */
 160   unsigned int nongroup:1;
 161 };
 162
 163 extern struct reload rld[MAX_RELOADS];
 164 extern int n_reloads;
 165 #endif
 166
 167 extern GTY (()) struct varray_head_tag *reg_equiv_memory_loc_varray;
 168 extern rtx *reg_equiv_constant;
 169 extern rtx *reg_equiv_memory_loc;
 170 extern rtx *reg_equiv_address;
 171 extern rtx *reg_equiv_mem;
 172
 173 /* All the "earlyclobber" operands of the current insn
 174    are recorded here.  */
 175 extern int n_earlyclobbers;
 176 extern rtx reload_earlyclobbers[MAX_RECOG_OPERANDS];
 177
 178 /* Save the number of operands.  */
 179 extern int reload_n_operands;
 180
 181 /* First uid used by insns created by reload in this function.
 182    Used in find_equiv_reg.  */
 183 extern int reload_first_uid;
 184
 185 /* Nonzero if an address (plus (reg frame_pointer) (reg ...)) is valid.  */
 186 extern char double_reg_address_ok;
 187
 188 extern int num_not_at_initial_offset;
 189
 190 #if defined SET_HARD_REG_BIT && defined CLEAR_REG_SET
 191 /* This structure describes instructions which are relevant for reload.
 192    Apart from all regular insns, this also includes CODE_LABELs, since they
 193    must be examined for register elimination.  */
 194 struct insn_chain
 195 {
 196   /* Links to the neighbor instructions.  */
 197   struct insn_chain *next, *prev;
 198
 199   /* Link through a chains set up by calculate_needs_all_insns, containing
 200      all insns that need reloading.  */
 201   struct insn_chain *next_need_reload;
 202
 203   /* The basic block this insn is in.  */
 204   int block;
 205   /* The rtx of the insn.  */
 206   rtx insn;
 207   /* Register life information: record all live hard registers, and all
 208      live pseudos that have a hard register.  */
 209   regset_head live_throughout;
 210   regset_head dead_or_set;
 211
 212   /* Copies of the global variables computed by find_reloads.  */
 213   struct reload *rld;
 214   int n_reloads;
 215
 216   /* Indicates which registers have already been used for spills.  */
 217   HARD_REG_SET used_spill_regs;
 218
 219   /* Nonzero if find_reloads said the insn requires reloading.  */
 220   unsigned int need_reload:1;
 221   /* Nonzero if find_reloads needs to be run during reload_as_needed to
 222      perform modifications on any operands.  */
 223   unsigned int need_operand_change:1;
 224   /* Nonzero if eliminate_regs_in_insn said it requires eliminations.  */
 225   unsigned int need_elim:1;
 226   /* Nonzero if this insn was inserted by perform_caller_saves.  */
 227   unsigned int is_caller_save_insn:1;
 228 };
 229
 230 /* A chain of insn_chain structures to describe all non-note insns in
 231    a function.  */
 232 extern struct insn_chain *reload_insn_chain;
 233
 234 /* Allocate a new insn_chain structure.  */
 235 extern struct insn_chain *new_insn_chain (void);
 236
 237 extern void compute_use_by_pseudos (HARD_REG_SET *, regset);
 238 #endif
 239
 240 /* Functions from reload.c:  */
 241
 242 /* Return a memory location that will be used to copy X in mode MODE.
 243    If we haven't already made a location for this mode in this insn,
 244    call find_reloads_address on the location being returned.  */
 245 extern rtx get_secondary_mem (rtx, enum machine_mode, int, enum reload_type);
 246
 247 /* Clear any secondary memory locations we've made.  */
 248 extern void clear_secondary_mem (void);
 249
 250 /* Transfer all replacements that used to be in reload FROM to be in
 251    reload TO.  */
 252 extern void transfer_replacements (int, int);
 253
 254 /* IN_RTX is the value loaded by a reload that we now decided to inherit,
 255    or a subpart of it.  If we have any replacements registered for IN_RTX,
 256    cancel the reloads that were supposed to load them.
 257    Return nonzero if we canceled any reloads.  */
 258 extern int remove_address_replacements (rtx in_rtx);
 259
 260 /* Like rtx_equal_p except that it allows a REG and a SUBREG to match
 261    if they are the same hard reg, and has special hacks for
 262    autoincrement and autodecrement.  */
 263 extern int operands_match_p (rtx, rtx);
 264
 265 /* Return 1 if altering OP will not modify the value of CLOBBER.  */
 266 extern int safe_from_earlyclobber (rtx, rtx);
 267
 268 /* Search the body of INSN for values that need reloading and record them
 269    with push_reload.  REPLACE nonzero means record also where the values occur
 270    so that subst_reloads can be used.  */
 271 extern int find_reloads (rtx, int, int, int, short *);
 272
 273 /* Compute the sum of X and Y, making canonicalizations assumed in an
 274    address, namely: sum constant integers, surround the sum of two
 275    constants with a CONST, put the constant as the second operand, and
 276    group the constant on the outermost sum.  */
 277 extern rtx form_sum (rtx, rtx);
 278
 279 /* Substitute into the current INSN the registers into which we have reloaded
 280    the things that need reloading.  */
 281 extern void subst_reloads (rtx);
 282
 283 /* Make a copy of any replacements being done into X and move those copies
 284    to locations in Y, a copy of X.  We only look at the highest level of
 285    the RTL.  */
 286 extern void copy_replacements (rtx, rtx);
 287
 288 /* Change any replacements being done to *X to be done to *Y */
 289 extern void move_replacements (rtx *x, rtx *y);
 290
 291 /* If LOC was scheduled to be replaced by something, return the replacement.
 292    Otherwise, return *LOC.  */
 293 extern rtx find_replacement (rtx *);
 294
 295 /* Nonzero if modifying X will affect IN.  */
 296 extern int reg_overlap_mentioned_for_reload_p (rtx, rtx);
 297
 298 /* Check the insns before INSN to see if there is a suitable register
 299    containing the same value as GOAL.  */
 300 extern rtx find_equiv_reg (rtx, rtx, enum reg_class, int, short *,
 301                            int, enum machine_mode);
 302
 303 /* Return 1 if register REGNO is the subject of a clobber in insn INSN.  */
 304 extern int regno_clobbered_p (unsigned int, rtx, enum machine_mode, int);
 305
 306 /* Return 1 if X is an operand of an insn that is being earlyclobbered.  */
 307 extern int earlyclobber_operand_p (rtx);
 308
 309 /* Record one reload that needs to be performed.  */
 310 extern int push_reload (rtx, rtx, rtx *, rtx *, enum reg_class,
 311                         enum machine_mode, enum machine_mode,
 312                         int, int, int, enum reload_type);
 313
 314 /* Functions in postreload.c:  */
 315 extern void reload_cse_regs (rtx);
 316
 317 /* Functions in reload1.c:  */
 318
 319 /* Initialize the reload pass once per compilation.  */
 320 extern void init_reload (void);
 321
 322 /* The reload pass itself.  */
 323 extern int reload (rtx, int);
 324
 325 /* Mark the slots in regs_ever_live for the hard regs
 326    used by pseudo-reg number REGNO.  */
 327 extern void mark_home_live (int);
 328
 329 /* Scan X and replace any eliminable registers (such as fp) with a
 330    replacement (such as sp), plus an offset.  */
 331 extern rtx eliminate_regs (rtx, enum machine_mode, rtx);
 332
 333 /* Deallocate the reload register used by reload number R.  */
 334 extern void deallocate_reload_reg (int r);
 335
 336 /* Functions in caller-save.c:  */
 337
 338 /* Initialize for caller-save.  */
 339 extern void init_caller_save (void);
 340
 341 /* Initialize save areas by showing that we haven't allocated any yet.  */
 342 extern void init_save_areas (void);
 343
 344 /* Allocate save areas for any hard registers that might need saving.  */
 345 extern void setup_save_areas (void);
 346
 347 /* Find the places where hard regs are live across calls and save them.  */
 348 extern void save_call_clobbered_regs (void);
 349
 350 /* Replace (subreg (reg)) with the appropriate (reg) for any operands.  */
 351 extern void cleanup_subreg_operands (rtx);
 352
 353 /* Debugging support.  */
 354 extern void debug_reload_to_stream (FILE *);
 355 extern void debug_reload (void);
 356
 357 /* Compute the actual register we should reload to, in case we're
 358    reloading to/from a register that is wider than a word.  */
 359 extern rtx reload_adjust_reg_for_mode (rtx, enum machine_mode);