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 tree split_complex_types (tree);
 192 tree split_complex_values (tree);
 193
 194 /* Supply a default definition of STACK_SAVEAREA_MODE for emit_stack_save.
 195    Normally move_insn, so Pmode stack pointer.  */
 196
 197 #ifndef STACK_SAVEAREA_MODE
 198 #define STACK_SAVEAREA_MODE(LEVEL) Pmode
 199 #endif
 200
 201 /* Supply a default definition of STACK_SIZE_MODE for
 202    allocate_dynamic_stack_space.  Normally PLUS/MINUS, so word_mode.  */
 203
 204 #ifndef STACK_SIZE_MODE
 205 #define STACK_SIZE_MODE word_mode
 206 #endif
 207
 208 /* Provide default values for the macros controlling stack checking.  */
 209
 210 #ifndef STACK_CHECK_BUILTIN
 211 #define STACK_CHECK_BUILTIN 0
 212 #endif
 213
 214 /* The default interval is one page.  */
 215 #ifndef STACK_CHECK_PROBE_INTERVAL
 216 #define STACK_CHECK_PROBE_INTERVAL 4096
 217 #endif
 218
 219 /* The default is to do a store into the stack.  */
 220 #ifndef STACK_CHECK_PROBE_LOAD
 221 #define STACK_CHECK_PROBE_LOAD 0
 222 #endif
 223
 224 /* This value is arbitrary, but should be sufficient for most machines.  */
 225 #ifndef STACK_CHECK_PROTECT
 226 #define STACK_CHECK_PROTECT (75 * UNITS_PER_WORD)
 227 #endif
 228
 229 /* Make the maximum frame size be the largest we can and still only need
 230    one probe per function.  */
 231 #ifndef STACK_CHECK_MAX_FRAME_SIZE
 232 #define STACK_CHECK_MAX_FRAME_SIZE \
 233   (STACK_CHECK_PROBE_INTERVAL - UNITS_PER_WORD)
 234 #endif
 235
 236 /* This is arbitrary, but should be large enough everywhere.  */
 237 #ifndef STACK_CHECK_FIXED_FRAME_SIZE
 238 #define STACK_CHECK_FIXED_FRAME_SIZE (4 * UNITS_PER_WORD)
 239 #endif
 240
 241 /* Provide a reasonable default for the maximum size of an object to
 242    allocate in the fixed frame.  We may need to be able to make this
 243    controllable by the user at some point.  */
 244 #ifndef STACK_CHECK_MAX_VAR_SIZE
 245 #define STACK_CHECK_MAX_VAR_SIZE (STACK_CHECK_MAX_FRAME_SIZE / 100)
 246 #endif
 247 \f
 248 /* Functions from optabs.c, commonly used, and without need for the optabs
 249    tables:  */
 250
 251 /* Passed to expand_simple_binop and expand_binop to say which options
 252    to try to use if the requested operation can't be open-coded on the
 253    requisite mode.  Either OPTAB_LIB or OPTAB_LIB_WIDEN says try using
 254    a library call.  Either OPTAB_WIDEN or OPTAB_LIB_WIDEN says try
 255    using a wider mode.  OPTAB_MUST_WIDEN says try widening and don't
 256    try anything else.  */
 257
 258 enum optab_methods
 259 {
 260   OPTAB_DIRECT,
 261   OPTAB_LIB,
 262   OPTAB_WIDEN,
 263   OPTAB_LIB_WIDEN,
 264   OPTAB_MUST_WIDEN
 265 };
 266
 267 /* Generate code for a simple binary or unary operation.  "Simple" in
 268    this case means "can be unambiguously described by a (mode, code)
 269    pair and mapped to a single optab."  */
 270 extern rtx expand_simple_binop (enum machine_mode, enum rtx_code, rtx,
 271                                 rtx, rtx, int, enum optab_methods);
 272 extern rtx expand_simple_unop (enum machine_mode, enum rtx_code, rtx, rtx,
 273                                int);
 274
 275 /* Report whether the machine description contains an insn which can
 276    perform the operation described by CODE and MODE.  */
 277 extern int have_insn_for (enum rtx_code, enum machine_mode);
 278
 279 /* Emit code to make a call to a constant function or a library call.  */
 280 extern void emit_libcall_block (rtx, rtx, rtx, rtx);
 281
 282 /* Create but don't emit one rtl instruction to perform certain operations.
 283    Modes must match; operands must meet the operation's predicates.
 284    Likewise for subtraction and for just copying.  */
 285 extern rtx gen_add2_insn (rtx, rtx);
 286 extern rtx gen_add3_insn (rtx, rtx, rtx);
 287 extern rtx gen_sub2_insn (rtx, rtx);
 288 extern rtx gen_sub3_insn (rtx, rtx, rtx);
 289 extern rtx gen_move_insn (rtx, rtx);
 290 extern int have_add2_insn (rtx, rtx);
 291 extern int have_sub2_insn (rtx, rtx);
 292
 293 /* Emit a pair of rtl insns to compare two rtx's and to jump
 294    to a label if the comparison is true.  */
 295 extern void emit_cmp_and_jump_insns (rtx, rtx, enum rtx_code, rtx,
 296                                      enum machine_mode, int, rtx);
 297
 298 /* Generate code to indirectly jump to a location given in the rtx LOC.  */
 299 extern void emit_indirect_jump (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
 333 /* Functions from loop.c:  */
 334
 335 /* Given an insn and condition, return a canonical description of
 336    the test being made.  */
 337 extern rtx canonicalize_condition (rtx, rtx, int, rtx *, rtx, int, int);
 338
 339 /* Given a JUMP_INSN, return a canonical description of the test
 340    being made.  */
 341 extern rtx get_condition (rtx, rtx *, int, int);
 342
 343 /* Generate a conditional trap instruction.  */
 344 extern rtx gen_cond_trap (enum rtx_code, rtx, rtx, rtx);
 345 \f
 346 /* Functions from builtins.c:  */
 347 extern rtx expand_builtin (tree, rtx, rtx, enum machine_mode, int);
 348 extern tree std_build_builtin_va_list (void);
 349 extern void std_expand_builtin_va_start (tree, rtx);
 350 extern rtx default_expand_builtin (tree, rtx, rtx, enum machine_mode, int);
 351 extern void expand_builtin_setjmp_setup (rtx, rtx);
 352 extern void expand_builtin_setjmp_receiver (rtx);
 353 extern void expand_builtin_longjmp (rtx, rtx);
 354 extern rtx expand_builtin_saveregs (void);
 355 extern void expand_builtin_trap (void);
 356 \f
 357 /* Functions from expr.c:  */
 358
 359 /* This is run once per compilation to set up which modes can be used
 360    directly in memory and to initialize the block move optab.  */
 361 extern void init_expr_once (void);
 362
 363 /* This is run at the start of compiling a function.  */
 364 extern void init_expr (void);
 365
 366 /* Emit some rtl insns to move data between rtx's, converting machine modes.
 367    Both modes must be floating or both fixed.  */
 368 extern void convert_move (rtx, rtx, int);
 369
 370 /* Convert an rtx to specified machine mode and return the result.  */
 371 extern rtx convert_to_mode (enum machine_mode, rtx, int);
 372
 373 /* Convert an rtx to MODE from OLDMODE and return the result.  */
 374 extern rtx convert_modes (enum machine_mode, enum machine_mode, rtx, int);
 375
 376 /* Emit code to move a block Y to a block X.  */
 377
 378 enum block_op_methods
 379 {
 380   BLOCK_OP_NORMAL,
 381   BLOCK_OP_NO_LIBCALL,
 382   BLOCK_OP_CALL_PARM
 383 };
 384
 385 extern void init_block_move_fn (const char *);
 386 extern void init_block_clear_fn (const char *);
 387
 388 extern rtx emit_block_move (rtx, rtx, rtx, enum block_op_methods);
 389
 390 /* Copy all or part of a value X into registers starting at REGNO.
 391    The number of registers to be filled is NREGS.  */
 392 extern void move_block_to_reg (int, rtx, int, enum machine_mode);
 393
 394 /* Copy all or part of a BLKmode value X out of registers starting at REGNO.
 395    The number of registers to be filled is NREGS.  */
 396 extern void move_block_from_reg (int, rtx, int);
 397
 398 /* Generate a non-consecutive group of registers represented by a PARALLEL.  */
 399 extern rtx gen_group_rtx (rtx);
 400
 401 /* Load a BLKmode value into non-consecutive registers represented by a
 402    PARALLEL.  */
 403 extern void emit_group_load (rtx, rtx, tree, int);
 404
 405 /* Move a non-consecutive group of registers represented by a PARALLEL into
 406    a non-consecutive group of registers represented by a PARALLEL.  */
 407 extern void emit_group_move (rtx, rtx);
 408
 409 /* Store a BLKmode value from non-consecutive registers represented by a
 410    PARALLEL.  */
 411 extern void emit_group_store (rtx, rtx, tree, int);
 412
 413 /* Copy BLKmode object from a set of registers.  */
 414 extern rtx copy_blkmode_from_reg (rtx, rtx, tree);
 415
 416 /* Mark REG as holding a parameter for the next CALL_INSN.  */
 417 extern void use_reg (rtx *, rtx);
 418
 419 /* Mark NREGS consecutive regs, starting at REGNO, as holding parameters
 420    for the next CALL_INSN.  */
 421 extern void use_regs (rtx *, int, int);
 422
 423 /* Mark a PARALLEL as holding a parameter for the next CALL_INSN.  */
 424 extern void use_group_regs (rtx *, rtx);
 425
 426 /* Write zeros through the storage of OBJECT.
 427    If OBJECT has BLKmode, SIZE is its length in bytes.  */
 428 extern rtx clear_storage (rtx, rtx);
 429
 430 /* Determine whether the LEN bytes can be moved by using several move
 431    instructions.  Return nonzero if a call to move_by_pieces should
 432    succeed.  */
 433 extern int can_move_by_pieces (unsigned HOST_WIDE_INT, unsigned int);
 434
 435 /* Return nonzero if it is desirable to store LEN bytes generated by
 436    CONSTFUN with several move instructions by store_by_pieces
 437    function.  CONSTFUNDATA is a pointer which will be passed as argument
 438    in every CONSTFUN call.
 439    ALIGN is maximum alignment we can assume.  */
 440 extern int can_store_by_pieces (unsigned HOST_WIDE_INT,
 441                                 rtx (*) (void *, HOST_WIDE_INT,
 442                                          enum machine_mode),
 443                                 void *, unsigned int);
 444
 445 /* Generate several move instructions to store LEN bytes generated by
 446    CONSTFUN to block TO.  (A MEM rtx with BLKmode).  CONSTFUNDATA is a
 447    pointer which will be passed as argument in every CONSTFUN call.
 448    ALIGN is maximum alignment we can assume.
 449    Returns TO + LEN.  */
 450 extern rtx store_by_pieces (rtx, unsigned HOST_WIDE_INT,
 451                             rtx (*) (void *, HOST_WIDE_INT, enum machine_mode),
 452                             void *, unsigned int, int);
 453
 454 /* Emit insns to set X from Y.  */
 455 extern rtx emit_move_insn (rtx, rtx);
 456
 457 /* Emit insns to set X from Y, with no frills.  */
 458 extern rtx emit_move_insn_1 (rtx, rtx);
 459
 460 /* Push a block of length SIZE (perhaps variable)
 461    and return an rtx to address the beginning of the block.  */
 462 extern rtx push_block (rtx, int, int);
 463
 464 /* Generate code to push something onto the stack, given its mode and type.  */
 465 extern void emit_push_insn (rtx, enum machine_mode, tree, rtx, unsigned int,
 466                             int, rtx, int, rtx, rtx, int, rtx);
 467
 468 /* Expand an assignment that stores the value of FROM into TO.  */
 469 extern void expand_assignment (tree, tree);
 470
 471 /* Generate code for computing expression EXP,
 472    and storing the value into TARGET.
 473    If SUGGEST_REG is nonzero, copy the value through a register
 474    and return that register, if that is possible.  */
 475 extern rtx store_expr (tree, rtx, int);
 476
 477 /* Given an rtx that may include add and multiply operations,
 478    generate them as insns and return a pseudo-reg containing the value.
 479    Useful after calling expand_expr with 1 as sum_ok.  */
 480 extern rtx force_operand (rtx, rtx);
 481
 482 /* Work horse for expand_expr.  */
 483 extern rtx expand_expr_real (tree, rtx, enum machine_mode,
 484                              enum expand_modifier, rtx *);
 485
 486 /* Generate code for computing expression EXP.
 487    An rtx for the computed value is returned.  The value is never null.
 488    In the case of a void EXP, const0_rtx is returned.  */
 489 static inline rtx
 490 expand_expr (tree exp, rtx target, enum machine_mode mode,
 491              enum expand_modifier modifier)
 492 {
 493   return expand_expr_real (exp, target, mode, modifier, NULL);
 494 }
 495
 496 extern void expand_var (tree);
 497
 498 /* At the start of a function, record that we have no previously-pushed
 499    arguments waiting to be popped.  */
 500 extern void init_pending_stack_adjust (void);
 501
 502 /* Discard any pending stack adjustment.  */
 503 extern void discard_pending_stack_adjust (void);
 504
 505 /* When exiting from function, if safe, clear out any pending stack adjust
 506    so the adjustment won't get done.  */
 507 extern void clear_pending_stack_adjust (void);
 508
 509 /* Pop any previously-pushed arguments that have not been popped yet.  */
 510 extern void do_pending_stack_adjust (void);
 511
 512 /* Return the tree node and offset if a given argument corresponds to
 513    a string constant.  */
 514 extern tree string_constant (tree, tree *);
 515
 516 /* Generate code to evaluate EXP and jump to LABEL if the value is zero.  */
 517 extern void jumpifnot (tree, rtx);
 518
 519 /* Generate code to evaluate EXP and jump to LABEL if the value is nonzero.  */
 520 extern void jumpif (tree, rtx);
 521
 522 /* Generate code to evaluate EXP and jump to IF_FALSE_LABEL if
 523    the result is zero, or IF_TRUE_LABEL if the result is one.  */
 524 extern void do_jump (tree, rtx, rtx);
 525
 526 /* Generate rtl to compare two rtx's, will call emit_cmp_insn.  */
 527 extern rtx compare_from_rtx (rtx, rtx, enum rtx_code, int, enum machine_mode,
 528                              rtx);
 529 extern void do_compare_rtx_and_jump (rtx, rtx, enum rtx_code, int,
 530                                      enum machine_mode, rtx, rtx, rtx);
 531
 532 /* Two different ways of generating switch statements.  */
 533 extern int try_casesi (tree, tree, tree, tree, rtx, rtx);
 534 extern int try_tablejump (tree, tree, tree, tree, rtx, rtx);
 535
 536 /* Smallest number of adjacent cases before we use a jump table.
 537    XXX Should be a target hook.  */
 538 extern unsigned int case_values_threshold (void);
 539
 540 /* Functions from alias.c */
 541 #include "alias.h"
 542 /* extern HOST_WIDE_INT get_varargs_alias_set (void); */
 543 /* extern HOST_WIDE_INT get_frame_alias_set (void); */
 544 /* extern void record_base_value (unsigned int, rtx, int); */
 545 /* extern void record_alias_subset (HOST_WIDE_INT, HOST_WIDE_INT); */
 546 /* extern HOST_WIDE_INT new_alias_set (void); */
 547 /* extern int can_address_p (tree); */
 548
 549 \f
 550 /* rtl.h and tree.h were included.  */
 551 /* Return an rtx for the size in bytes of the value of an expr.  */
 552 extern rtx expr_size (tree);
 553
 554 /* Return a wide integer for the size in bytes of the value of EXP, or -1
 555    if the size can vary or is larger than an integer.  */
 556 extern HOST_WIDE_INT int_expr_size (tree);
 557
 558 /* Return the address of the trampoline for entering nested fn FUNCTION.  */
 559 extern rtx trampoline_address (tree);
 560
 561 /* Return an rtx that refers to the value returned by a function
 562    in its original home.  This becomes invalid if any more code is emitted.  */
 563 extern rtx hard_function_value (tree, tree, int);
 564
 565 extern rtx prepare_call_address (rtx, rtx, rtx *, int, int);
 566
 567 extern rtx expand_call (tree, rtx, int);
 568
 569 extern void fixup_tail_calls (void);
 570
 571 #ifdef TREE_CODE
 572 extern rtx expand_shift (enum tree_code, enum machine_mode, rtx, tree, rtx,
 573                          int);
 574 extern rtx expand_divmod (int, enum tree_code, enum machine_mode, rtx, rtx,
 575                           rtx, int);
 576 #endif
 577
 578 extern void locate_and_pad_parm (enum machine_mode, tree, int, int, tree,
 579                                  struct args_size *,
 580                                  struct locate_and_pad_arg_data *);
 581
 582 /* Return the CODE_LABEL rtx for a LABEL_DECL, creating it if necessary.  */
 583 extern rtx label_rtx (tree);
 584
 585 /* As label_rtx, but additionally the label is placed on the forced label
 586    list of its containing function (i.e. it is treated as reachable even
 587    if how is not obvious).  */
 588 extern rtx force_label_rtx (tree);
 589
 590 /* Indicate how an input argument register was promoted.  */
 591 extern rtx promoted_input_arg (unsigned int, enum machine_mode *, int *);
 592
 593 /* Return an rtx like arg but sans any constant terms.
 594    Returns the original rtx if it has no constant terms.
 595    The constant terms are added and stored via a second arg.  */
 596 extern rtx eliminate_constant_term (rtx, rtx *);
 597
 598 /* Convert arg to a valid memory address for specified machine mode,
 599    by emitting insns to perform arithmetic if nec.  */
 600 extern rtx memory_address (enum machine_mode, rtx);
 601
 602 /* Like `memory_address' but pretent `flag_force_addr' is 0.  */
 603 extern rtx memory_address_noforce (enum machine_mode, rtx);
 604
 605 /* Return a memory reference like MEMREF, but with its mode changed
 606    to MODE and its address changed to ADDR.
 607    (VOIDmode means don't change the mode.
 608    NULL for ADDR means don't change the address.)  */
 609 extern rtx change_address (rtx, enum machine_mode, rtx);
 610
 611 /* Return a memory reference like MEMREF, but with its mode changed
 612    to MODE and its address offset by OFFSET bytes.  */
 613 #define adjust_address(MEMREF, MODE, OFFSET) \
 614   adjust_address_1 (MEMREF, MODE, OFFSET, 1, 1)
 615
 616 /* Likewise, but the reference is not required to be valid.  */
 617 #define adjust_address_nv(MEMREF, MODE, OFFSET) \
 618   adjust_address_1 (MEMREF, MODE, OFFSET, 0, 1)
 619
 620 /* Return a memory reference like MEMREF, but with its mode changed
 621    to MODE and its address changed to ADDR, which is assumed to be
 622    increased by OFFSET bytes from MEMREF.  */
 623 #define adjust_automodify_address(MEMREF, MODE, ADDR, OFFSET) \
 624   adjust_automodify_address_1 (MEMREF, MODE, ADDR, OFFSET, 1)
 625
 626 /* Likewise, but the reference is not required to be valid.  */
 627 #define adjust_automodify_address_nv(MEMREF, MODE, ADDR, OFFSET) \
 628   adjust_automodify_address_1 (MEMREF, MODE, ADDR, OFFSET, 0)
 629
 630 extern rtx adjust_address_1 (rtx, enum machine_mode, HOST_WIDE_INT, int, int);
 631 extern rtx adjust_automodify_address_1 (rtx, enum machine_mode, rtx,
 632                                         HOST_WIDE_INT, int);
 633
 634 /* Return a memory reference like MEMREF, but whose address is changed by
 635    adding OFFSET, an RTX, to it.  POW2 is the highest power of two factor
 636    known to be in OFFSET (possibly 1).  */
 637 extern rtx offset_address (rtx, rtx, unsigned HOST_WIDE_INT);
 638
 639 /* Definitions from emit-rtl.c */
 640 #include "emit-rtl.h"
 641
 642 /* Return a memory reference like MEMREF, but with its mode widened to
 643    MODE and adjusted by OFFSET.  */
 644 extern rtx widen_memory_access (rtx, enum machine_mode, HOST_WIDE_INT);
 645
 646 /* Return a memory reference like MEMREF, but which is known to have a
 647    valid address.  */
 648 extern rtx validize_mem (rtx);
 649
 650 /* Given REF, a MEM, and T, either the type of X or the expression
 651    corresponding to REF, set the memory attributes.  OBJECTP is nonzero
 652    if we are making a new object of this type.  */
 653 extern void set_mem_attributes (rtx, tree, int);
 654
 655 /* Similar, except that BITPOS has not yet been applied to REF, so if
 656    we alter MEM_OFFSET according to T then we should subtract BITPOS
 657    expecting that it'll be added back in later.  */
 658 extern void set_mem_attributes_minus_bitpos (rtx, tree, int, HOST_WIDE_INT);
 659
 660 /* Assemble the static constant template for function entry trampolines.  */
 661 extern rtx assemble_trampoline_template (void);
 662
 663 /* Given rtx, return new rtx whose address won't be affected by
 664    any side effects.  It has been copied to a new temporary reg.  */
 665 extern rtx stabilize (rtx);
 666
 667 /* Given an rtx, copy all regs it refers to into new temps
 668    and return a modified copy that refers to the new temps.  */
 669 extern rtx copy_all_regs (rtx);
 670
 671 /* Copy given rtx to a new temp reg and return that.  */
 672 extern rtx copy_to_reg (rtx);
 673
 674 /* Like copy_to_reg but always make the reg Pmode.  */
 675 extern rtx copy_addr_to_reg (rtx);
 676
 677 /* Like copy_to_reg but always make the reg the specified mode MODE.  */
 678 extern rtx copy_to_mode_reg (enum machine_mode, rtx);
 679
 680 /* Copy given rtx to given temp reg and return that.  */
 681 extern rtx copy_to_suggested_reg (rtx, rtx, enum machine_mode);
 682
 683 /* Copy a value to a register if it isn't already a register.
 684    Args are mode (in case value is a constant) and the value.  */
 685 extern rtx force_reg (enum machine_mode, rtx);
 686
 687 /* Return given rtx, copied into a new temp reg if it was in memory.  */
 688 extern rtx force_not_mem (rtx);
 689
 690 /* Return mode and signedness to use when object is promoted.  */
 691 extern enum machine_mode promote_mode (tree, enum machine_mode, int *, int);
 692
 693 /* Remove some bytes from the stack.  An rtx says how many.  */
 694 extern void adjust_stack (rtx);
 695
 696 /* Add some bytes to the stack.  An rtx says how many.  */
 697 extern void anti_adjust_stack (rtx);
 698
 699 /* This enum is used for the following two functions.  */
 700 enum save_level {SAVE_BLOCK, SAVE_FUNCTION, SAVE_NONLOCAL};
 701
 702 /* Save the stack pointer at the specified level.  */
 703 extern void emit_stack_save (enum save_level, rtx *, rtx);
 704
 705 /* Restore the stack pointer from a save area of the specified level.  */
 706 extern void emit_stack_restore (enum save_level, rtx, rtx);
 707
 708 /* Invoke emit_stack_save for the nonlocal_goto_save_area.  */
 709 extern void update_nonlocal_goto_save_area (void);
 710
 711 /* Allocate some space on the stack dynamically and return its address.  An rtx
 712    says how many bytes.  */
 713 extern rtx allocate_dynamic_stack_space (rtx, rtx, int);
 714
 715 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
 716    FIRST is a constant and size is a Pmode RTX.  These are offsets from the
 717    current stack pointer.  STACK_GROWS_DOWNWARD says whether to add or
 718    subtract from the stack.  If SIZE is constant, this is done
 719    with a fixed number of probes.  Otherwise, we must make a loop.  */
 720 extern void probe_stack_range (HOST_WIDE_INT, rtx);
 721
 722 /* Return an rtx that refers to the value returned by a library call
 723    in its original home.  This becomes invalid if any more code is emitted.  */
 724 extern rtx hard_libcall_value (enum machine_mode);
 725
 726 /* Given an rtx, return an rtx for a value rounded up to a multiple
 727    of STACK_BOUNDARY / BITS_PER_UNIT.  */
 728 extern rtx round_push (rtx);
 729
 730 /* Return the mode desired by operand N of a particular bitfield
 731    insert/extract insn, or MAX_MACHINE_MODE if no such insn is
 732    available.  */
 733
 734 enum extraction_pattern { EP_insv, EP_extv, EP_extzv };
 735 extern enum machine_mode
 736 mode_for_extraction (enum extraction_pattern, int);
 737
 738 extern rtx store_bit_field (rtx, unsigned HOST_WIDE_INT,
 739                             unsigned HOST_WIDE_INT, enum machine_mode, rtx);
 740 extern rtx extract_bit_field (rtx, unsigned HOST_WIDE_INT,
 741                               unsigned HOST_WIDE_INT, int, rtx,
 742                               enum machine_mode, enum machine_mode);
 743 extern rtx expand_mult (enum machine_mode, rtx, rtx, rtx, int);
 744 extern bool const_mult_add_overflow_p (rtx, rtx, rtx, enum machine_mode, int);
 745 extern rtx expand_mult_add (rtx, rtx, rtx, rtx,enum machine_mode, int);
 746 extern rtx expand_mult_highpart_adjust (enum machine_mode, rtx, rtx, rtx, rtx, int);
 747
 748 extern rtx assemble_static_space (unsigned HOST_WIDE_INT);
 749 extern int safe_from_p (rtx, tree, int);
 750
 751 /* Call this once to initialize the contents of the optabs
 752    appropriately for the current target machine.  */
 753 extern void init_optabs (void);
 754 extern void init_all_optabs (void);
 755
 756 /* Call this to initialize an optab function entry.  */
 757 extern rtx init_one_libfunc (const char *);
 758
 759 extern void do_jump_by_parts_equality_rtx (rtx, rtx, rtx);
 760 extern void do_jump_by_parts_greater_rtx (enum machine_mode, int, rtx, rtx,
 761                                           rtx, rtx);
 762
 763 extern int vector_mode_valid_p (enum machine_mode);
 764
 765 #endif /* GCC_EXPR_H */