gcc/expr.h

   1 /* Definitions for code generation pass of GNU compiler.
   2    Copyright (C) 1987, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   3    1999, 2000, 2001, 2002, 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 #ifndef GCC_EXPR_H
  23 #define GCC_EXPR_H
  24
  25 /* For inhibit_defer_pop */
  26 #include "function.h"
  27 /* For XEXP, GEN_INT, rtx_code */
  28 #include "rtl.h"
  29 /* For optimize_size */
  30 #include "flags.h"
  31 /* For host_integerp, tree_low_cst, convert, size_binop, ssize_int, TREE_CODE,
  32    TYPE_SIZE, int_size_in_bytes,    */
  33 #include "tree.h"
  34 /* For GET_MODE_BITSIZE, word_mode */
  35 #include "machmode.h"
  36
  37 /* The default branch cost is 1.  */
  38 #ifndef BRANCH_COST
  39 #define BRANCH_COST 1
  40 #endif
  41
  42 /* This is the 4th arg to `expand_expr'.
  43    EXPAND_STACK_PARM means we are possibly expanding a call param onto
  44    the stack.  Choosing a value of 2 isn't special;  It just allows
  45    some code optimization in store_expr.
  46    EXPAND_SUM means it is ok to return a PLUS rtx or MULT rtx.
  47    EXPAND_INITIALIZER is similar but also record any labels on forced_labels.
  48    EXPAND_CONST_ADDRESS means it is ok to return a MEM whose address
  49     is a constant that is not a legitimate address.
  50    EXPAND_WRITE means we are only going to write to the resulting rtx.
  51    EXPAND_MEMORY means we are interested in a memory result, even if
  52     the memory is constant and we could have propagated a constant value.  */
  53 enum expand_modifier {EXPAND_NORMAL = 0, EXPAND_STACK_PARM = 2, EXPAND_SUM,
  54                       EXPAND_CONST_ADDRESS, EXPAND_INITIALIZER, EXPAND_WRITE,
  55                       EXPAND_MEMORY};
  56
  57 /* Prevent the compiler from deferring stack pops.  See
  58    inhibit_defer_pop for more information.  */
  59 #define NO_DEFER_POP (inhibit_defer_pop += 1)
  60
  61 /* Allow the compiler to defer stack pops.  See inhibit_defer_pop for
  62    more information.  */
  63 #define OK_DEFER_POP (inhibit_defer_pop -= 1)
  64 \f
  65 /* If a memory-to-memory move would take MOVE_RATIO or more simple
  66    move-instruction sequences, we will do a movmem or libcall instead.  */
  67
  68 #ifndef MOVE_RATIO
  69 #if defined (HAVE_movmemqi) || defined (HAVE_movmemhi) || defined (HAVE_movmemsi) || defined (HAVE_movmemdi) || defined (HAVE_movmemti)
  70 #define MOVE_RATIO 2
  71 #else
  72 /* If we are optimizing for space (-Os), cut down the default move ratio.  */
  73 #define MOVE_RATIO (optimize_size ? 3 : 15)
  74 #endif
  75 #endif
  76
  77 /* If a clear memory operation would take CLEAR_RATIO or more simple
  78    move-instruction sequences, we will do a clrmem or libcall instead.  */
  79
  80 #ifndef CLEAR_RATIO
  81 #if defined (HAVE_clrmemqi) || defined (HAVE_clrmemhi) || defined (HAVE_clrmemsi) || defined (HAVE_clrmemdi) || defined (HAVE_clrmemti)
  82 #define CLEAR_RATIO 2
  83 #else
  84 /* If we are optimizing for space, cut down the default clear ratio.  */
  85 #define CLEAR_RATIO (optimize_size ? 3 : 15)
  86 #endif
  87 #endif
  88 \f
  89 enum direction {none, upward, downward};
  90
  91 /* Structure to record the size of a sequence of arguments
  92    as the sum of a tree-expression and a constant.  This structure is
  93    also used to store offsets from the stack, which might be negative,
  94    so the variable part must be ssizetype, not sizetype.  */
  95
  96 struct args_size
  97 {
  98   HOST_WIDE_INT constant;
  99   tree var;
 100 };
 101
 102 /* Package up various arg related fields of struct args for
 103    locate_and_pad_parm.  */
 104 struct locate_and_pad_arg_data
 105 {
 106   /* Size of this argument on the stack, rounded up for any padding it
 107      gets.  If REG_PARM_STACK_SPACE is defined, then register parms are
 108      counted here, otherwise they aren't.  */
 109   struct args_size size;
 110   /* Offset of this argument from beginning of stack-args.  */
 111   struct args_size offset;
 112   /* Offset to the start of the stack slot.  Different from OFFSET
 113      if this arg pads downward.  */
 114   struct args_size slot_offset;
 115   /* The amount that the stack pointer needs to be adjusted to
 116      force alignment for the next argument.  */
 117   struct args_size alignment_pad;
 118   /* Which way we should pad this arg.  */
 119   enum direction where_pad;
 120 };
 121
 122 /* Add the value of the tree INC to the `struct args_size' TO.  */
 123
 124 #define ADD_PARM_SIZE(TO, INC)                          \
 125 do {                                                    \
 126   tree inc = (INC);                                     \
 127   if (host_integerp (inc, 0))                           \
 128     (TO).constant += tree_low_cst (inc, 0);             \
 129   else if ((TO).var == 0)                               \
 130     (TO).var = convert (ssizetype, inc);                \
 131   else                                                  \
 132     (TO).var = size_binop (PLUS_EXPR, (TO).var,         \
 133                            convert (ssizetype, inc));   \
 134 } while (0)
 135
 136 #define SUB_PARM_SIZE(TO, DEC)                          \
 137 do {                                                    \
 138   tree dec = (DEC);                                     \
 139   if (host_integerp (dec, 0))                           \
 140     (TO).constant -= tree_low_cst (dec, 0);             \
 141   else if ((TO).var == 0)                               \
 142     (TO).var = size_binop (MINUS_EXPR, ssize_int (0),   \
 143                            convert (ssizetype, dec));   \
 144   else                                                  \
 145     (TO).var = size_binop (MINUS_EXPR, (TO).var,        \
 146                            convert (ssizetype, dec));   \
 147 } while (0)
 148
 149 /* Convert the implicit sum in a `struct args_size' into a tree
 150    of type ssizetype.  */
 151 #define ARGS_SIZE_TREE(SIZE)                                    \
 152 ((SIZE).var == 0 ? ssize_int ((SIZE).constant)                  \
 153  : size_binop (PLUS_EXPR, convert (ssizetype, (SIZE).var),      \
 154                ssize_int ((SIZE).constant)))
 155
 156 /* Convert the implicit sum in a `struct args_size' into an rtx.  */
 157 #define ARGS_SIZE_RTX(SIZE)                                     \
 158 ((SIZE).var == 0 ? GEN_INT ((SIZE).constant)                    \
 159  : expand_expr (ARGS_SIZE_TREE (SIZE), NULL_RTX, VOIDmode, 0))
 160
 161 /* Supply a default definition for FUNCTION_ARG_PADDING:
 162    usually pad upward, but pad short args downward on
 163    big-endian machines.  */
 164
 165 #define DEFAULT_FUNCTION_ARG_PADDING(MODE, TYPE)                        \
 166   (! BYTES_BIG_ENDIAN                                                   \
 167    ? upward                                                             \
 168    : (((MODE) == BLKmode                                                \
 169        ? ((TYPE) && TREE_CODE (TYPE_SIZE (TYPE)) == INTEGER_CST         \
 170           && int_size_in_bytes (TYPE) < (PARM_BOUNDARY / BITS_PER_UNIT)) \
 171        : GET_MODE_BITSIZE (MODE) < PARM_BOUNDARY)                       \
 172       ? downward : upward))
 173
 174 #ifndef FUNCTION_ARG_PADDING
 175 #define FUNCTION_ARG_PADDING(MODE, TYPE)        \
 176   DEFAULT_FUNCTION_ARG_PADDING ((MODE), (TYPE))
 177 #endif
 178
 179 /* Supply a default definition for FUNCTION_ARG_BOUNDARY.  Normally, we let
 180    FUNCTION_ARG_PADDING, which also pads the length, handle any needed
 181    alignment.  */
 182
 183 #ifndef FUNCTION_ARG_BOUNDARY
 184 #define FUNCTION_ARG_BOUNDARY(MODE, TYPE)       PARM_BOUNDARY
 185 #endif
 186
 187 #ifndef FUNCTION_ARG_PARTIAL_NREGS
 188 #define FUNCTION_ARG_PARTIAL_NREGS(CUM, MODE, TYPE, NAMED) 0
 189 #endif
 190
 191 /* Supply a default definition of STACK_SAVEAREA_MODE for emit_stack_save.
 192    Normally move_insn, so Pmode stack pointer.  */
 193
 194 #ifndef STACK_SAVEAREA_MODE
 195 #define STACK_SAVEAREA_MODE(LEVEL) Pmode
 196 #endif
 197
 198 /* Supply a default definition of STACK_SIZE_MODE for
 199    allocate_dynamic_stack_space.  Normally PLUS/MINUS, so word_mode.  */
 200
 201 #ifndef STACK_SIZE_MODE
 202 #define STACK_SIZE_MODE word_mode
 203 #endif
 204
 205 /* Provide default values for the macros controlling stack checking.  */
 206
 207 #ifndef STACK_CHECK_BUILTIN
 208 #define STACK_CHECK_BUILTIN 0
 209 #endif
 210
 211 /* The default interval is one page.  */
 212 #ifndef STACK_CHECK_PROBE_INTERVAL
 213 #define STACK_CHECK_PROBE_INTERVAL 4096
 214 #endif
 215
 216 /* The default is to do a store into the stack.  */
 217 #ifndef STACK_CHECK_PROBE_LOAD
 218 #define STACK_CHECK_PROBE_LOAD 0
 219 #endif
 220
 221 /* This value is arbitrary, but should be sufficient for most machines.  */
 222 #ifndef STACK_CHECK_PROTECT
 223 #define STACK_CHECK_PROTECT (75 * UNITS_PER_WORD)
 224 #endif
 225
 226 /* Make the maximum frame size be the largest we can and still only need
 227    one probe per function.  */
 228 #ifndef STACK_CHECK_MAX_FRAME_SIZE
 229 #define STACK_CHECK_MAX_FRAME_SIZE \
 230   (STACK_CHECK_PROBE_INTERVAL - UNITS_PER_WORD)
 231 #endif
 232
 233 /* This is arbitrary, but should be large enough everywhere.  */
 234 #ifndef STACK_CHECK_FIXED_FRAME_SIZE
 235 #define STACK_CHECK_FIXED_FRAME_SIZE (4 * UNITS_PER_WORD)
 236 #endif
 237
 238 /* Provide a reasonable default for the maximum size of an object to
 239    allocate in the fixed frame.  We may need to be able to make this
 240    controllable by the user at some point.  */
 241 #ifndef STACK_CHECK_MAX_VAR_SIZE
 242 #define STACK_CHECK_MAX_VAR_SIZE (STACK_CHECK_MAX_FRAME_SIZE / 100)
 243 #endif
 244 \f
 245 /* Functions from optabs.c, commonly used, and without need for the optabs
 246    tables:  */
 247
 248 /* Passed to expand_simple_binop and expand_binop to say which options
 249    to try to use if the requested operation can't be open-coded on the
 250    requisite mode.  Either OPTAB_LIB or OPTAB_LIB_WIDEN says try using
 251    a library call.  Either OPTAB_WIDEN or OPTAB_LIB_WIDEN says try
 252    using a wider mode.  OPTAB_MUST_WIDEN says try widening and don't
 253    try anything else.  */
 254
 255 enum optab_methods
 256 {
 257   OPTAB_DIRECT,
 258   OPTAB_LIB,
 259   OPTAB_WIDEN,
 260   OPTAB_LIB_WIDEN,
 261   OPTAB_MUST_WIDEN
 262 };
 263
 264 /* Generate code for a simple binary or unary operation.  "Simple" in
 265    this case means "can be unambiguously described by a (mode, code)
 266    pair and mapped to a single optab."  */
 267 extern rtx expand_simple_binop (enum machine_mode, enum rtx_code, rtx,
 268                                 rtx, rtx, int, enum optab_methods);
 269 extern rtx expand_simple_unop (enum machine_mode, enum rtx_code, rtx, rtx,
 270                                int);
 271
 272 /* Report whether the machine description contains an insn which can
 273    perform the operation described by CODE and MODE.  */
 274 extern int have_insn_for (enum rtx_code, enum machine_mode);
 275
 276 /* Emit code to make a call to a constant function or a library call.  */
 277 extern void emit_libcall_block (rtx, rtx, rtx, rtx);
 278
 279 /* Create but don't emit one rtl instruction to perform certain operations.
 280    Modes must match; operands must meet the operation's predicates.
 281    Likewise for subtraction and for just copying.  */
 282 extern rtx gen_add2_insn (rtx, rtx);
 283 extern rtx gen_add3_insn (rtx, rtx, rtx);
 284 extern rtx gen_sub2_insn (rtx, rtx);
 285 extern rtx gen_sub3_insn (rtx, rtx, rtx);
 286 extern rtx gen_move_insn (rtx, rtx);
 287 extern int have_add2_insn (rtx, rtx);
 288 extern int have_sub2_insn (rtx, rtx);
 289
 290 /* Emit a pair of rtl insns to compare two rtx's and to jump
 291    to a label if the comparison is true.  */
 292 extern void emit_cmp_and_jump_insns (rtx, rtx, enum rtx_code, rtx,
 293                                      enum machine_mode, int, rtx);
 294
 295 /* Generate code to indirectly jump to a location given in the rtx LOC.  */
 296 extern void emit_indirect_jump (rtx);
 297
 298 /* Generate a conditional trap instruction.  */
 299 extern rtx gen_cond_trap (enum rtx_code, rtx, rtx, rtx);
 300
 301 #include "insn-config.h"
 302
 303 #ifdef HAVE_conditional_move
 304 /* Emit a conditional move operation.  */
 305 rtx emit_conditional_move (rtx, enum rtx_code, rtx, rtx, enum machine_mode,
 306                            rtx, rtx, enum machine_mode, int);
 307
 308 /* Return nonzero if the conditional move is supported.  */
 309 int can_conditionally_move_p (enum machine_mode mode);
 310
 311 #endif
 312 rtx emit_conditional_add (rtx, enum rtx_code, rtx, rtx, enum machine_mode,
 313                           rtx, rtx, enum machine_mode, int);
 314
 315 \f
 316 /* Functions from expmed.c:  */
 317
 318 /* Arguments MODE, RTX: return an rtx for the negation of that value.
 319    May emit insns.  */
 320 extern rtx negate_rtx (enum machine_mode, rtx);
 321
 322 /* Expand a logical AND operation.  */
 323 extern rtx expand_and (enum machine_mode, rtx, rtx, rtx);
 324
 325 /* Emit a store-flag operation.  */
 326 extern rtx emit_store_flag (rtx, enum rtx_code, rtx, rtx, enum machine_mode,
 327                             int, int);
 328
 329 /* Like emit_store_flag, but always succeeds.  */
 330 extern rtx emit_store_flag_force (rtx, enum rtx_code, rtx, rtx,
 331                                   enum machine_mode, int, int);
 332 \f
 333 /* Functions from builtins.c:  */
 334 extern rtx expand_builtin (tree, rtx, rtx, enum machine_mode, int);
 335 extern tree std_build_builtin_va_list (void);
 336 extern void std_expand_builtin_va_start (tree, rtx);
 337 extern rtx default_expand_builtin (tree, rtx, rtx, enum machine_mode, int);
 338 extern void expand_builtin_setjmp_setup (rtx, rtx);
 339 extern void expand_builtin_setjmp_receiver (rtx);
 340 extern rtx expand_builtin_saveregs (void);
 341 \f
 342 /* Functions from expr.c:  */
 343
 344 /* This is run once per compilation to set up which modes can be used
 345    directly in memory and to initialize the block move optab.  */
 346 extern void init_expr_once (void);
 347
 348 /* This is run at the start of compiling a function.  */
 349 extern void init_expr (void);
 350
 351 /* Emit some rtl insns to move data between rtx's, converting machine modes.
 352    Both modes must be floating or both fixed.  */
 353 extern void convert_move (rtx, rtx, int);
 354
 355 /* Convert an rtx to specified machine mode and return the result.  */
 356 extern rtx convert_to_mode (enum machine_mode, rtx, int);
 357
 358 /* Convert an rtx to MODE from OLDMODE and return the result.  */
 359 extern rtx convert_modes (enum machine_mode, enum machine_mode, rtx, int);
 360
 361 /* Emit code to move a block Y to a block X.  */
 362
 363 enum block_op_methods
 364 {
 365   BLOCK_OP_NORMAL,
 366   BLOCK_OP_NO_LIBCALL,
 367   BLOCK_OP_CALL_PARM
 368 };
 369
 370 extern void init_block_move_fn (const char *);
 371 extern void init_block_clear_fn (const char *);
 372
 373 extern rtx emit_block_move (rtx, rtx, rtx, enum block_op_methods);
 374
 375 /* Copy all or part of a value X into registers starting at REGNO.
 376    The number of registers to be filled is NREGS.  */
 377 extern void move_block_to_reg (int, rtx, int, enum machine_mode);
 378
 379 /* Copy all or part of a BLKmode value X out of registers starting at REGNO.
 380    The number of registers to be filled is NREGS.  */
 381 extern void move_block_from_reg (int, rtx, int);
 382
 383 /* Generate a non-consecutive group of registers represented by a PARALLEL.  */
 384 extern rtx gen_group_rtx (rtx);
 385
 386 /* Load a BLKmode value into non-consecutive registers represented by a
 387    PARALLEL.  */
 388 extern void emit_group_load (rtx, rtx, tree, int);
 389
 390 /* Move a non-consecutive group of registers represented by a PARALLEL into
 391    a non-consecutive group of registers represented by a PARALLEL.  */
 392 extern void emit_group_move (rtx, rtx);
 393
 394 /* Store a BLKmode value from non-consecutive registers represented by a
 395    PARALLEL.  */
 396 extern void emit_group_store (rtx, rtx, tree, int);
 397
 398 /* Copy BLKmode object from a set of registers.  */
 399 extern rtx copy_blkmode_from_reg (rtx, rtx, tree);
 400
 401 /* Mark REG as holding a parameter for the next CALL_INSN.  */
 402 extern void use_reg (rtx *, rtx);
 403
 404 /* Mark NREGS consecutive regs, starting at REGNO, as holding parameters
 405    for the next CALL_INSN.  */
 406 extern void use_regs (rtx *, int, int);
 407
 408 /* Mark a PARALLEL as holding a parameter for the next CALL_INSN.  */
 409 extern void use_group_regs (rtx *, rtx);
 410
 411 /* Write zeros through the storage of OBJECT.
 412    If OBJECT has BLKmode, SIZE is its length in bytes.  */
 413 extern rtx clear_storage (rtx, rtx);
 414
 415 /* Determine whether the LEN bytes can be moved by using several move
 416    instructions.  Return nonzero if a call to move_by_pieces should
 417    succeed.  */
 418 extern int can_move_by_pieces (unsigned HOST_WIDE_INT, unsigned int);
 419
 420 /* Return nonzero if it is desirable to store LEN bytes generated by
 421    CONSTFUN with several move instructions by store_by_pieces
 422    function.  CONSTFUNDATA is a pointer which will be passed as argument
 423    in every CONSTFUN call.
 424    ALIGN is maximum alignment we can assume.  */
 425 extern int can_store_by_pieces (unsigned HOST_WIDE_INT,
 426                                 rtx (*) (void *, HOST_WIDE_INT,
 427                                          enum machine_mode),
 428                                 void *, unsigned int);
 429
 430 /* Generate several move instructions to store LEN bytes generated by
 431    CONSTFUN to block TO.  (A MEM rtx with BLKmode).  CONSTFUNDATA is a
 432    pointer which will be passed as argument in every CONSTFUN call.
 433    ALIGN is maximum alignment we can assume.
 434    Returns TO + LEN.  */
 435 extern rtx store_by_pieces (rtx, unsigned HOST_WIDE_INT,
 436                             rtx (*) (void *, HOST_WIDE_INT, enum machine_mode),
 437                             void *, unsigned int, int);
 438
 439 /* Emit insns to set X from Y.  */
 440 extern rtx emit_move_insn (rtx, rtx);
 441
 442 /* Emit insns to set X from Y, with no frills.  */
 443 extern rtx emit_move_insn_1 (rtx, rtx);
 444
 445 /* Push a block of length SIZE (perhaps variable)
 446    and return an rtx to address the beginning of the block.  */
 447 extern rtx push_block (rtx, int, int);
 448
 449 /* Generate code to push something onto the stack, given its mode and type.  */
 450 extern void emit_push_insn (rtx, enum machine_mode, tree, rtx, unsigned int,
 451                             int, rtx, int, rtx, rtx, int, rtx);
 452
 453 /* Expand an assignment that stores the value of FROM into TO.  */
 454 extern void expand_assignment (tree, tree);
 455
 456 /* Generate code for computing expression EXP,
 457    and storing the value into TARGET.
 458    If SUGGEST_REG is nonzero, copy the value through a register
 459    and return that register, if that is possible.  */
 460 extern rtx store_expr (tree, rtx, int);
 461
 462 /* Given an rtx that may include add and multiply operations,
 463    generate them as insns and return a pseudo-reg containing the value.
 464    Useful after calling expand_expr with 1 as sum_ok.  */
 465 extern rtx force_operand (rtx, rtx);
 466
 467 /* Work horse for expand_expr.  */
 468 extern rtx expand_expr_real (tree, rtx, enum machine_mode,
 469                              enum expand_modifier, rtx *);
 470
 471 /* Generate code for computing expression EXP.
 472    An rtx for the computed value is returned.  The value is never null.
 473    In the case of a void EXP, const0_rtx is returned.  */
 474 static inline rtx
 475 expand_expr (tree exp, rtx target, enum machine_mode mode,
 476              enum expand_modifier modifier)
 477 {
 478   return expand_expr_real (exp, target, mode, modifier, NULL);
 479 }
 480
 481 extern void expand_var (tree);
 482
 483 /* At the start of a function, record that we have no previously-pushed
 484    arguments waiting to be popped.  */
 485 extern void init_pending_stack_adjust (void);
 486
 487 /* Discard any pending stack adjustment.  */
 488 extern void discard_pending_stack_adjust (void);
 489
 490 /* When exiting from function, if safe, clear out any pending stack adjust
 491    so the adjustment won't get done.  */
 492 extern void clear_pending_stack_adjust (void);
 493
 494 /* Pop any previously-pushed arguments that have not been popped yet.  */
 495 extern void do_pending_stack_adjust (void);
 496
 497 /* Return the tree node and offset if a given argument corresponds to
 498    a string constant.  */
 499 extern tree string_constant (tree, tree *);
 500
 501 /* Generate code to evaluate EXP and jump to LABEL if the value is zero.  */
 502 extern void jumpifnot (tree, rtx);
 503
 504 /* Generate code to evaluate EXP and jump to LABEL if the value is nonzero.  */
 505 extern void jumpif (tree, rtx);
 506
 507 /* Generate code to evaluate EXP and jump to IF_FALSE_LABEL if
 508    the result is zero, or IF_TRUE_LABEL if the result is one.  */
 509 extern void do_jump (tree, rtx, rtx);
 510
 511 /* Generate rtl to compare two rtx's, will call emit_cmp_insn.  */
 512 extern rtx compare_from_rtx (rtx, rtx, enum rtx_code, int, enum machine_mode,
 513                              rtx);
 514 extern void do_compare_rtx_and_jump (rtx, rtx, enum rtx_code, int,
 515                                      enum machine_mode, rtx, rtx, rtx);
 516
 517 /* Two different ways of generating switch statements.  */
 518 extern int try_casesi (tree, tree, tree, tree, rtx, rtx);
 519 extern int try_tablejump (tree, tree, tree, tree, rtx, rtx);
 520
 521 /* Smallest number of adjacent cases before we use a jump table.
 522    XXX Should be a target hook.  */
 523 extern unsigned int case_values_threshold (void);
 524
 525 /* Functions from alias.c */
 526 #include "alias.h"
 527 /* extern HOST_WIDE_INT get_varargs_alias_set (void); */
 528 /* extern HOST_WIDE_INT get_frame_alias_set (void); */
 529 /* extern void record_base_value (unsigned int, rtx, int); */
 530 /* extern void record_alias_subset (HOST_WIDE_INT, HOST_WIDE_INT); */
 531 /* extern HOST_WIDE_INT new_alias_set (void); */
 532 /* extern int can_address_p (tree); */
 533
 534 \f
 535 /* rtl.h and tree.h were included.  */
 536 /* Return an rtx for the size in bytes of the value of an expr.  */
 537 extern rtx expr_size (tree);
 538
 539 /* Return a wide integer for the size in bytes of the value of EXP, or -1
 540    if the size can vary or is larger than an integer.  */
 541 extern HOST_WIDE_INT int_expr_size (tree);
 542
 543 /* Return the address of the trampoline for entering nested fn FUNCTION.  */
 544 extern rtx trampoline_address (tree);
 545
 546 /* Return an rtx that refers to the value returned by a function
 547    in its original home.  This becomes invalid if any more code is emitted.  */
 548 extern rtx hard_function_value (tree, tree, int);
 549
 550 extern rtx prepare_call_address (rtx, rtx, rtx *, int, int);
 551
 552 extern rtx expand_call (tree, rtx, int);
 553
 554 extern void fixup_tail_calls (void);
 555
 556 #ifdef TREE_CODE
 557 extern rtx expand_shift (enum tree_code, enum machine_mode, rtx, tree, rtx,
 558                          int);
 559 extern rtx expand_divmod (int, enum tree_code, enum machine_mode, rtx, rtx,
 560                           rtx, int);
 561 #endif
 562
 563 extern void locate_and_pad_parm (enum machine_mode, tree, int, int, tree,
 564                                  struct args_size *,
 565                                  struct locate_and_pad_arg_data *);
 566
 567 /* Return the CODE_LABEL rtx for a LABEL_DECL, creating it if necessary.  */
 568 extern rtx label_rtx (tree);
 569
 570 /* As label_rtx, but additionally the label is placed on the forced label
 571    list of its containing function (i.e. it is treated as reachable even
 572    if how is not obvious).  */
 573 extern rtx force_label_rtx (tree);
 574
 575 /* Indicate how an input argument register was promoted.  */
 576 extern rtx promoted_input_arg (unsigned int, enum machine_mode *, int *);
 577
 578 /* Return an rtx like arg but sans any constant terms.
 579    Returns the original rtx if it has no constant terms.
 580    The constant terms are added and stored via a second arg.  */
 581 extern rtx eliminate_constant_term (rtx, rtx *);
 582
 583 /* Convert arg to a valid memory address for specified machine mode,
 584    by emitting insns to perform arithmetic if nec.  */
 585 extern rtx memory_address (enum machine_mode, rtx);
 586
 587 /* Like `memory_address' but pretent `flag_force_addr' is 0.  */
 588 extern rtx memory_address_noforce (enum machine_mode, rtx);
 589
 590 /* Return a memory reference like MEMREF, but with its mode changed
 591    to MODE and its address changed to ADDR.
 592    (VOIDmode means don't change the mode.
 593    NULL for ADDR means don't change the address.)  */
 594 extern rtx change_address (rtx, enum machine_mode, rtx);
 595
 596 /* Return a memory reference like MEMREF, but with its mode changed
 597    to MODE and its address offset by OFFSET bytes.  */
 598 #define adjust_address(MEMREF, MODE, OFFSET) \
 599   adjust_address_1 (MEMREF, MODE, OFFSET, 1, 1)
 600
 601 /* Likewise, but the reference is not required to be valid.  */
 602 #define adjust_address_nv(MEMREF, MODE, OFFSET) \
 603   adjust_address_1 (MEMREF, MODE, OFFSET, 0, 1)
 604
 605 /* Return a memory reference like MEMREF, but with its mode changed
 606    to MODE and its address changed to ADDR, which is assumed to be
 607    increased by OFFSET bytes from MEMREF.  */
 608 #define adjust_automodify_address(MEMREF, MODE, ADDR, OFFSET) \
 609   adjust_automodify_address_1 (MEMREF, MODE, ADDR, OFFSET, 1)
 610
 611 /* Likewise, but the reference is not required to be valid.  */
 612 #define adjust_automodify_address_nv(MEMREF, MODE, ADDR, OFFSET) \
 613   adjust_automodify_address_1 (MEMREF, MODE, ADDR, OFFSET, 0)
 614
 615 extern rtx adjust_address_1 (rtx, enum machine_mode, HOST_WIDE_INT, int, int);
 616 extern rtx adjust_automodify_address_1 (rtx, enum machine_mode, rtx,
 617                                         HOST_WIDE_INT, int);
 618
 619 /* Return a memory reference like MEMREF, but whose address is changed by
 620    adding OFFSET, an RTX, to it.  POW2 is the highest power of two factor
 621    known to be in OFFSET (possibly 1).  */
 622 extern rtx offset_address (rtx, rtx, unsigned HOST_WIDE_INT);
 623
 624 /* Definitions from emit-rtl.c */
 625 #include "emit-rtl.h"
 626
 627 /* Return a memory reference like MEMREF, but with its mode widened to
 628    MODE and adjusted by OFFSET.  */
 629 extern rtx widen_memory_access (rtx, enum machine_mode, HOST_WIDE_INT);
 630
 631 /* Return a memory reference like MEMREF, but which is known to have a
 632    valid address.  */
 633 extern rtx validize_mem (rtx);
 634
 635 /* Given REF, a MEM, and T, either the type of X or the expression
 636    corresponding to REF, set the memory attributes.  OBJECTP is nonzero
 637    if we are making a new object of this type.  */
 638 extern void set_mem_attributes (rtx, tree, int);
 639
 640 /* Similar, except that BITPOS has not yet been applied to REF, so if
 641    we alter MEM_OFFSET according to T then we should subtract BITPOS
 642    expecting that it'll be added back in later.  */
 643 extern void set_mem_attributes_minus_bitpos (rtx, tree, int, HOST_WIDE_INT);
 644
 645 /* Assemble the static constant template for function entry trampolines.  */
 646 extern rtx assemble_trampoline_template (void);
 647
 648 /* Given rtx, return new rtx whose address won't be affected by
 649    any side effects.  It has been copied to a new temporary reg.  */
 650 extern rtx stabilize (rtx);
 651
 652 /* Given an rtx, copy all regs it refers to into new temps
 653    and return a modified copy that refers to the new temps.  */
 654 extern rtx copy_all_regs (rtx);
 655
 656 /* Copy given rtx to a new temp reg and return that.  */
 657 extern rtx copy_to_reg (rtx);
 658
 659 /* Like copy_to_reg but always make the reg Pmode.  */
 660 extern rtx copy_addr_to_reg (rtx);
 661
 662 /* Like copy_to_reg but always make the reg the specified mode MODE.  */
 663 extern rtx copy_to_mode_reg (enum machine_mode, rtx);
 664
 665 /* Copy given rtx to given temp reg and return that.  */
 666 extern rtx copy_to_suggested_reg (rtx, rtx, enum machine_mode);
 667
 668 /* Copy a value to a register if it isn't already a register.
 669    Args are mode (in case value is a constant) and the value.  */
 670 extern rtx force_reg (enum machine_mode, rtx);
 671
 672 /* Return given rtx, copied into a new temp reg if it was in memory.  */
 673 extern rtx force_not_mem (rtx);
 674
 675 /* Return mode and signedness to use when object is promoted.  */
 676 extern enum machine_mode promote_mode (tree, enum machine_mode, int *, int);
 677
 678 /* Remove some bytes from the stack.  An rtx says how many.  */
 679 extern void adjust_stack (rtx);
 680
 681 /* Add some bytes to the stack.  An rtx says how many.  */
 682 extern void anti_adjust_stack (rtx);
 683
 684 /* This enum is used for the following two functions.  */
 685 enum save_level {SAVE_BLOCK, SAVE_FUNCTION, SAVE_NONLOCAL};
 686
 687 /* Save the stack pointer at the specified level.  */
 688 extern void emit_stack_save (enum save_level, rtx *, rtx);
 689
 690 /* Restore the stack pointer from a save area of the specified level.  */
 691 extern void emit_stack_restore (enum save_level, rtx, rtx);
 692
 693 /* Invoke emit_stack_save for the nonlocal_goto_save_area.  */
 694 extern void update_nonlocal_goto_save_area (void);
 695
 696 /* Allocate some space on the stack dynamically and return its address.  An rtx
 697    says how many bytes.  */
 698 extern rtx allocate_dynamic_stack_space (rtx, rtx, int);
 699
 700 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
 701    FIRST is a constant and size is a Pmode RTX.  These are offsets from the
 702    current stack pointer.  STACK_GROWS_DOWNWARD says whether to add or
 703    subtract from the stack.  If SIZE is constant, this is done
 704    with a fixed number of probes.  Otherwise, we must make a loop.  */
 705 extern void probe_stack_range (HOST_WIDE_INT, rtx);
 706
 707 /* Return an rtx that refers to the value returned by a library call
 708    in its original home.  This becomes invalid if any more code is emitted.  */
 709 extern rtx hard_libcall_value (enum machine_mode);
 710
 711 /* Given an rtx, return an rtx for a value rounded up to a multiple
 712    of STACK_BOUNDARY / BITS_PER_UNIT.  */
 713 extern rtx round_push (rtx);
 714
 715 /* Return the mode desired by operand N of a particular bitfield
 716    insert/extract insn, or MAX_MACHINE_MODE if no such insn is
 717    available.  */
 718
 719 enum extraction_pattern { EP_insv, EP_extv, EP_extzv };
 720 extern enum machine_mode
 721 mode_for_extraction (enum extraction_pattern, int);
 722
 723 extern rtx store_bit_field (rtx, unsigned HOST_WIDE_INT,
 724                             unsigned HOST_WIDE_INT, enum machine_mode, rtx);
 725 extern rtx extract_bit_field (rtx, unsigned HOST_WIDE_INT,
 726                               unsigned HOST_WIDE_INT, int, rtx,
 727                               enum machine_mode, enum machine_mode);
 728 extern rtx expand_mult (enum machine_mode, rtx, rtx, rtx, int);
 729 extern bool const_mult_add_overflow_p (rtx, rtx, rtx, enum machine_mode, int);
 730 extern rtx expand_mult_add (rtx, rtx, rtx, rtx,enum machine_mode, int);
 731 extern rtx expand_mult_highpart_adjust (enum machine_mode, rtx, rtx, rtx, rtx, int);
 732
 733 extern rtx assemble_static_space (unsigned HOST_WIDE_INT);
 734 extern int safe_from_p (rtx, tree, int);
 735
 736 /* Call this once to initialize the contents of the optabs
 737    appropriately for the current target machine.  */
 738 extern void init_optabs (void);
 739 extern void init_all_optabs (void);
 740
 741 /* Call this to initialize an optab function entry.  */
 742 extern rtx init_one_libfunc (const char *);
 743
 744 extern void do_jump_by_parts_equality_rtx (rtx, rtx, rtx);
 745 extern void do_jump_by_parts_greater_rtx (enum machine_mode, int, rtx, rtx,
 746                                           rtx, rtx);
 747
 748 extern int vector_mode_valid_p (enum machine_mode);
 749
 750 #endif /* GCC_EXPR_H */