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, 2005
   4    Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 2, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING.  If not, write to the Free
  20 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  21 02111-1307, USA.  */
  22
  23 #ifndef GCC_EXPR_H
  24 #define GCC_EXPR_H
  25
  26 /* For inhibit_defer_pop */
  27 #include "function.h"
  28 /* For XEXP, GEN_INT, rtx_code */
  29 #include "rtl.h"
  30 /* For optimize_size */
  31 #include "flags.h"
  32 /* For host_integerp, tree_low_cst, convert, size_binop, ssize_int, TREE_CODE,
  33    TYPE_SIZE, int_size_in_bytes,    */
  34 #include "tree.h"
  35 /* For GET_MODE_BITSIZE, word_mode */
  36 #include "machmode.h"
  37
  38 /* The default branch cost is 1.  */
  39 #ifndef BRANCH_COST
  40 #define BRANCH_COST 1
  41 #endif
  42
  43 /* This is the 4th arg to `expand_expr'.
  44    EXPAND_STACK_PARM means we are possibly expanding a call param onto
  45    the stack.
  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, 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   /* slot_offset is at least this aligned.  */
 121   unsigned int boundary;
 122 };
 123
 124 /* Add the value of the tree INC to the `struct args_size' TO.  */
 125
 126 #define ADD_PARM_SIZE(TO, INC)                          \
 127 do {                                                    \
 128   tree inc = (INC);                                     \
 129   if (host_integerp (inc, 0))                           \
 130     (TO).constant += tree_low_cst (inc, 0);             \
 131   else if ((TO).var == 0)                               \
 132     (TO).var = convert (ssizetype, inc);                \
 133   else                                                  \
 134     (TO).var = size_binop (PLUS_EXPR, (TO).var,         \
 135                            convert (ssizetype, inc));   \
 136 } while (0)
 137
 138 #define SUB_PARM_SIZE(TO, DEC)                          \
 139 do {                                                    \
 140   tree dec = (DEC);                                     \
 141   if (host_integerp (dec, 0))                           \
 142     (TO).constant -= tree_low_cst (dec, 0);             \
 143   else if ((TO).var == 0)                               \
 144     (TO).var = size_binop (MINUS_EXPR, ssize_int (0),   \
 145                            convert (ssizetype, dec));   \
 146   else                                                  \
 147     (TO).var = size_binop (MINUS_EXPR, (TO).var,        \
 148                            convert (ssizetype, dec));   \
 149 } while (0)
 150
 151 /* Convert the implicit sum in a `struct args_size' into a tree
 152    of type ssizetype.  */
 153 #define ARGS_SIZE_TREE(SIZE)                                    \
 154 ((SIZE).var == 0 ? ssize_int ((SIZE).constant)                  \
 155  : size_binop (PLUS_EXPR, convert (ssizetype, (SIZE).var),      \
 156                ssize_int ((SIZE).constant)))
 157
 158 /* Convert the implicit sum in a `struct args_size' into an rtx.  */
 159 #define ARGS_SIZE_RTX(SIZE)                                     \
 160 ((SIZE).var == 0 ? GEN_INT ((SIZE).constant)                    \
 161  : expand_expr (ARGS_SIZE_TREE (SIZE), NULL_RTX, VOIDmode, 0))
 162
 163 /* Supply a default definition for FUNCTION_ARG_PADDING:
 164    usually pad upward, but pad short args downward on
 165    big-endian machines.  */
 166
 167 #define DEFAULT_FUNCTION_ARG_PADDING(MODE, TYPE)                        \
 168   (! BYTES_BIG_ENDIAN                                                   \
 169    ? upward                                                             \
 170    : (((MODE) == BLKmode                                                \
 171        ? ((TYPE) && TREE_CODE (TYPE_SIZE (TYPE)) == INTEGER_CST         \
 172           && int_size_in_bytes (TYPE) < (PARM_BOUNDARY / BITS_PER_UNIT)) \
 173        : GET_MODE_BITSIZE (MODE) < PARM_BOUNDARY)                       \
 174       ? downward : upward))
 175
 176 #ifndef FUNCTION_ARG_PADDING
 177 #define FUNCTION_ARG_PADDING(MODE, TYPE)        \
 178   DEFAULT_FUNCTION_ARG_PADDING ((MODE), (TYPE))
 179 #endif
 180
 181 /* Supply a default definition for FUNCTION_ARG_BOUNDARY.  Normally, we let
 182    FUNCTION_ARG_PADDING, which also pads the length, handle any needed
 183    alignment.  */
 184
 185 #ifndef FUNCTION_ARG_BOUNDARY
 186 #define FUNCTION_ARG_BOUNDARY(MODE, TYPE)       PARM_BOUNDARY
 187 #endif
 188
 189 /* Supply a default definition of STACK_SAVEAREA_MODE for emit_stack_save.
 190    Normally move_insn, so Pmode stack pointer.  */
 191
 192 #ifndef STACK_SAVEAREA_MODE
 193 #define STACK_SAVEAREA_MODE(LEVEL) Pmode
 194 #endif
 195
 196 /* Supply a default definition of STACK_SIZE_MODE for
 197    allocate_dynamic_stack_space.  Normally PLUS/MINUS, so word_mode.  */
 198
 199 #ifndef STACK_SIZE_MODE
 200 #define STACK_SIZE_MODE word_mode
 201 #endif
 202
 203 /* Provide default values for the macros controlling stack checking.  */
 204
 205 #ifndef STACK_CHECK_BUILTIN
 206 #define STACK_CHECK_BUILTIN 0
 207 #endif
 208
 209 /* The default interval is one page.  */
 210 #ifndef STACK_CHECK_PROBE_INTERVAL
 211 #define STACK_CHECK_PROBE_INTERVAL 4096
 212 #endif
 213
 214 /* The default is to do a store into the stack.  */
 215 #ifndef STACK_CHECK_PROBE_LOAD
 216 #define STACK_CHECK_PROBE_LOAD 0
 217 #endif
 218
 219 /* This value is arbitrary, but should be sufficient for most machines.  */
 220 #ifndef STACK_CHECK_PROTECT
 221 #define STACK_CHECK_PROTECT (75 * UNITS_PER_WORD)
 222 #endif
 223
 224 /* Make the maximum frame size be the largest we can and still only need
 225    one probe per function.  */
 226 #ifndef STACK_CHECK_MAX_FRAME_SIZE
 227 #define STACK_CHECK_MAX_FRAME_SIZE \
 228   (STACK_CHECK_PROBE_INTERVAL - UNITS_PER_WORD)
 229 #endif
 230
 231 /* This is arbitrary, but should be large enough everywhere.  */
 232 #ifndef STACK_CHECK_FIXED_FRAME_SIZE
 233 #define STACK_CHECK_FIXED_FRAME_SIZE (4 * UNITS_PER_WORD)
 234 #endif
 235
 236 /* Provide a reasonable default for the maximum size of an object to
 237    allocate in the fixed frame.  We may need to be able to make this
 238    controllable by the user at some point.  */
 239 #ifndef STACK_CHECK_MAX_VAR_SIZE
 240 #define STACK_CHECK_MAX_VAR_SIZE (STACK_CHECK_MAX_FRAME_SIZE / 100)
 241 #endif
 242 \f
 243 /* Functions from optabs.c, commonly used, and without need for the optabs
 244    tables:  */
 245
 246 /* Passed to expand_simple_binop and expand_binop to say which options
 247    to try to use if the requested operation can't be open-coded on the
 248    requisite mode.  Either OPTAB_LIB or OPTAB_LIB_WIDEN says try using
 249    a library call.  Either OPTAB_WIDEN or OPTAB_LIB_WIDEN says try
 250    using a wider mode.  OPTAB_MUST_WIDEN says try widening and don't
 251    try anything else.  */
 252
 253 enum optab_methods
 254 {
 255   OPTAB_DIRECT,
 256   OPTAB_LIB,
 257   OPTAB_WIDEN,
 258   OPTAB_LIB_WIDEN,
 259   OPTAB_MUST_WIDEN
 260 };
 261
 262 /* Generate code for a simple binary or unary operation.  "Simple" in
 263    this case means "can be unambiguously described by a (mode, code)
 264    pair and mapped to a single optab."  */
 265 extern rtx expand_simple_binop (enum machine_mode, enum rtx_code, rtx,
 266                                 rtx, rtx, int, enum optab_methods);
 267 extern rtx expand_simple_unop (enum machine_mode, enum rtx_code, rtx, rtx,
 268                                int);
 269
 270 /* Report whether the machine description contains an insn which can
 271    perform the operation described by CODE and MODE.  */
 272 extern int have_insn_for (enum rtx_code, enum machine_mode);
 273
 274 /* Emit code to make a call to a constant function or a library call.  */
 275 extern void emit_libcall_block (rtx, rtx, rtx, rtx);
 276
 277 /* Create but don't emit one rtl instruction to perform certain operations.
 278    Modes must match; operands must meet the operation's predicates.
 279    Likewise for subtraction and for just copying.  */
 280 extern rtx gen_add2_insn (rtx, rtx);
 281 extern rtx gen_add3_insn (rtx, rtx, rtx);
 282 extern rtx gen_sub2_insn (rtx, rtx);
 283 extern rtx gen_sub3_insn (rtx, rtx, rtx);
 284 extern rtx gen_move_insn (rtx, rtx);
 285 extern int have_add2_insn (rtx, rtx);
 286 extern int have_sub2_insn (rtx, rtx);
 287
 288 /* Emit a pair of rtl insns to compare two rtx's and to jump
 289    to a label if the comparison is true.  */
 290 extern void emit_cmp_and_jump_insns (rtx, rtx, enum rtx_code, rtx,
 291                                      enum machine_mode, int, rtx);
 292
 293 /* Generate code to indirectly jump to a location given in the rtx LOC.  */
 294 extern void emit_indirect_jump (rtx);
 295
 296 /* Generate a conditional trap instruction.  */
 297 extern rtx gen_cond_trap (enum rtx_code, rtx, rtx, rtx);
 298
 299 #include "insn-config.h"
 300
 301 #ifdef HAVE_conditional_move
 302 /* Emit a conditional move operation.  */
 303 rtx emit_conditional_move (rtx, enum rtx_code, rtx, rtx, enum machine_mode,
 304                            rtx, rtx, enum machine_mode, int);
 305
 306 /* Return nonzero if the conditional move is supported.  */
 307 int can_conditionally_move_p (enum machine_mode mode);
 308
 309 #endif
 310 rtx emit_conditional_add (rtx, enum rtx_code, rtx, rtx, enum machine_mode,
 311                           rtx, rtx, enum machine_mode, int);
 312
 313 rtx expand_val_compare_and_swap (rtx, rtx, rtx, rtx);
 314 rtx expand_bool_compare_and_swap (rtx, rtx, rtx, rtx);
 315 rtx expand_sync_operation (rtx, rtx, enum rtx_code);
 316 rtx expand_sync_fetch_operation (rtx, rtx, enum rtx_code, bool, rtx);
 317 rtx expand_sync_lock_test_and_set (rtx, rtx, rtx);
 318 \f
 319 /* Functions from expmed.c:  */
 320
 321 /* Arguments MODE, RTX: return an rtx for the negation of that value.
 322    May emit insns.  */
 323 extern rtx negate_rtx (enum machine_mode, rtx);
 324
 325 /* Expand a logical AND operation.  */
 326 extern rtx expand_and (enum machine_mode, rtx, rtx, rtx);
 327
 328 /* Emit a store-flag operation.  */
 329 extern rtx emit_store_flag (rtx, enum rtx_code, rtx, rtx, enum machine_mode,
 330                             int, int);
 331
 332 /* Like emit_store_flag, but always succeeds.  */
 333 extern rtx emit_store_flag_force (rtx, enum rtx_code, rtx, rtx,
 334                                   enum machine_mode, int, int);
 335 \f
 336 /* Functions from builtins.c:  */
 337 extern rtx expand_builtin (tree, rtx, rtx, enum machine_mode, int);
 338 extern tree std_build_builtin_va_list (void);
 339 extern void std_expand_builtin_va_start (tree, rtx);
 340 extern rtx default_expand_builtin (tree, rtx, rtx, enum machine_mode, int);
 341 extern void expand_builtin_setjmp_setup (rtx, rtx);
 342 extern void expand_builtin_setjmp_receiver (rtx);
 343 extern rtx expand_builtin_saveregs (void);
 344 \f
 345 /* Functions from expr.c:  */
 346
 347 /* This is run once per compilation to set up which modes can be used
 348    directly in memory and to initialize the block move optab.  */
 349 extern void init_expr_once (void);
 350
 351 /* This is run at the start of compiling a function.  */
 352 extern void init_expr (void);
 353
 354 /* Emit some rtl insns to move data between rtx's, converting machine modes.
 355    Both modes must be floating or both fixed.  */
 356 extern void convert_move (rtx, rtx, int);
 357
 358 /* Convert an rtx to specified machine mode and return the result.  */
 359 extern rtx convert_to_mode (enum machine_mode, rtx, int);
 360
 361 /* Convert an rtx to MODE from OLDMODE and return the result.  */
 362 extern rtx convert_modes (enum machine_mode, enum machine_mode, rtx, int);
 363
 364 /* Emit code to move a block Y to a block X.  */
 365
 366 enum block_op_methods
 367 {
 368   BLOCK_OP_NORMAL,
 369   BLOCK_OP_NO_LIBCALL,
 370   BLOCK_OP_CALL_PARM,
 371   /* Like BLOCK_OP_NORMAL, but the libcall can be tail call optimized.  */
 372   BLOCK_OP_TAILCALL
 373 };
 374
 375 extern void init_block_move_fn (const char *);
 376 extern void init_block_clear_fn (const char *);
 377
 378 extern rtx emit_block_move (rtx, rtx, rtx, enum block_op_methods);
 379
 380 /* Copy all or part of a value X into registers starting at REGNO.
 381    The number of registers to be filled is NREGS.  */
 382 extern void move_block_to_reg (int, rtx, int, enum machine_mode);
 383
 384 /* Copy all or part of a BLKmode value X out of registers starting at REGNO.
 385    The number of registers to be filled is NREGS.  */
 386 extern void move_block_from_reg (int, rtx, int);
 387
 388 /* Generate a non-consecutive group of registers represented by a PARALLEL.  */
 389 extern rtx gen_group_rtx (rtx);
 390
 391 /* Load a BLKmode value into non-consecutive registers represented by a
 392    PARALLEL.  */
 393 extern void emit_group_load (rtx, rtx, tree, int);
 394
 395 /* Similarly, but load into new temporaries.  */
 396 extern rtx emit_group_load_into_temps (rtx, rtx, tree, int);
 397
 398 /* Move a non-consecutive group of registers represented by a PARALLEL into
 399    a non-consecutive group of registers represented by a PARALLEL.  */
 400 extern void emit_group_move (rtx, rtx);
 401
 402 /* Move a group of registers represented by a PARALLEL into pseudos.  */
 403 extern rtx emit_group_move_into_temps (rtx);
 404
 405 /* Store a BLKmode value from non-consecutive registers represented by a
 406    PARALLEL.  */
 407 extern void emit_group_store (rtx, rtx, tree, int);
 408
 409 /* Copy BLKmode object from a set of registers.  */
 410 extern rtx copy_blkmode_from_reg (rtx, rtx, tree);
 411
 412 /* Mark REG as holding a parameter for the next CALL_INSN.  */
 413 extern void use_reg (rtx *, rtx);
 414
 415 /* Mark NREGS consecutive regs, starting at REGNO, as holding parameters
 416    for the next CALL_INSN.  */
 417 extern void use_regs (rtx *, int, int);
 418
 419 /* Mark a PARALLEL as holding a parameter for the next CALL_INSN.  */
 420 extern void use_group_regs (rtx *, rtx);
 421
 422 /* Write zeros through the storage of OBJECT.
 423    If OBJECT has BLKmode, SIZE is its length in bytes.  */
 424 extern rtx clear_storage (rtx, rtx, enum block_op_methods);
 425
 426 /* Determine whether the LEN bytes can be moved by using several move
 427    instructions.  Return nonzero if a call to move_by_pieces should
 428    succeed.  */
 429 extern int can_move_by_pieces (unsigned HOST_WIDE_INT, unsigned int);
 430
 431 /* Return nonzero if it is desirable to store LEN bytes generated by
 432    CONSTFUN with several move instructions by store_by_pieces
 433    function.  CONSTFUNDATA is a pointer which will be passed as argument
 434    in every CONSTFUN call.
 435    ALIGN is maximum alignment we can assume.  */
 436 extern int can_store_by_pieces (unsigned HOST_WIDE_INT,
 437                                 rtx (*) (void *, HOST_WIDE_INT,
 438                                          enum machine_mode),
 439                                 void *, unsigned int);
 440
 441 /* Generate several move instructions to store LEN bytes generated by
 442    CONSTFUN to block TO.  (A MEM rtx with BLKmode).  CONSTFUNDATA is a
 443    pointer which will be passed as argument in every CONSTFUN call.
 444    ALIGN is maximum alignment we can assume.
 445    Returns TO + LEN.  */
 446 extern rtx store_by_pieces (rtx, unsigned HOST_WIDE_INT,
 447                             rtx (*) (void *, HOST_WIDE_INT, enum machine_mode),
 448                             void *, unsigned int, int);
 449
 450 /* Emit insns to set X from Y.  */
 451 extern rtx emit_move_insn (rtx, rtx);
 452
 453 /* Emit insns to set X from Y, with no frills.  */
 454 extern rtx emit_move_insn_1 (rtx, rtx);
 455
 456 /* Push a block of length SIZE (perhaps variable)
 457    and return an rtx to address the beginning of the block.  */
 458 extern rtx push_block (rtx, int, int);
 459
 460 /* Generate code to push something onto the stack, given its mode and type.  */
 461 extern void emit_push_insn (rtx, enum machine_mode, tree, rtx, unsigned int,
 462                             int, rtx, int, rtx, rtx, int, rtx);
 463
 464 /* Expand an assignment that stores the value of FROM into TO.  */
 465 extern void expand_assignment (tree, tree);
 466
 467 /* Generate code for computing expression EXP,
 468    and storing the value into TARGET.
 469    If SUGGEST_REG is nonzero, copy the value through a register
 470    and return that register, if that is possible.  */
 471 extern rtx store_expr (tree, rtx, int);
 472
 473 /* Given an rtx that may include add and multiply operations,
 474    generate them as insns and return a pseudo-reg containing the value.
 475    Useful after calling expand_expr with 1 as sum_ok.  */
 476 extern rtx force_operand (rtx, rtx);
 477
 478 /* Work horse for expand_expr.  */
 479 extern rtx expand_expr_real (tree, rtx, enum machine_mode,
 480                              enum expand_modifier, rtx *);
 481
 482 /* Generate code for computing expression EXP.
 483    An rtx for the computed value is returned.  The value is never null.
 484    In the case of a void EXP, const0_rtx is returned.  */
 485 static inline rtx
 486 expand_expr (tree exp, rtx target, enum machine_mode mode,
 487              enum expand_modifier modifier)
 488 {
 489   return expand_expr_real (exp, target, mode, modifier, NULL);
 490 }
 491
 492 extern void expand_var (tree);
 493
 494 /* At the start of a function, record that we have no previously-pushed
 495    arguments waiting to be popped.  */
 496 extern void init_pending_stack_adjust (void);
 497
 498 /* Discard any pending stack adjustment.  */
 499 extern void discard_pending_stack_adjust (void);
 500
 501 /* When exiting from function, if safe, clear out any pending stack adjust
 502    so the adjustment won't get done.  */
 503 extern void clear_pending_stack_adjust (void);
 504
 505 /* Pop any previously-pushed arguments that have not been popped yet.  */
 506 extern void do_pending_stack_adjust (void);
 507
 508 /* Return the tree node and offset if a given argument corresponds to
 509    a string constant.  */
 510 extern tree string_constant (tree, tree *);
 511
 512 /* Generate code to evaluate EXP and jump to LABEL if the value is zero.  */
 513 extern void jumpifnot (tree, rtx);
 514
 515 /* Generate code to evaluate EXP and jump to LABEL if the value is nonzero.  */
 516 extern void jumpif (tree, rtx);
 517
 518 /* Generate code to evaluate EXP and jump to IF_FALSE_LABEL if
 519    the result is zero, or IF_TRUE_LABEL if the result is one.  */
 520 extern void do_jump (tree, rtx, rtx);
 521
 522 /* Generate rtl to compare two rtx's, will call emit_cmp_insn.  */
 523 extern rtx compare_from_rtx (rtx, rtx, enum rtx_code, int, enum machine_mode,
 524                              rtx);
 525 extern void do_compare_rtx_and_jump (rtx, rtx, enum rtx_code, int,
 526                                      enum machine_mode, rtx, rtx, rtx);
 527
 528 /* Two different ways of generating switch statements.  */
 529 extern int try_casesi (tree, tree, tree, tree, rtx, rtx);
 530 extern int try_tablejump (tree, tree, tree, tree, rtx, rtx);
 531
 532 /* Smallest number of adjacent cases before we use a jump table.
 533    XXX Should be a target hook.  */
 534 extern unsigned int case_values_threshold (void);
 535
 536 /* Functions from alias.c */
 537 #include "alias.h"
 538
 539 \f
 540 /* rtl.h and tree.h were included.  */
 541 /* Return an rtx for the size in bytes of the value of an expr.  */
 542 extern rtx expr_size (tree);
 543
 544 /* Return a wide integer for the size in bytes of the value of EXP, or -1
 545    if the size can vary or is larger than an integer.  */
 546 extern HOST_WIDE_INT int_expr_size (tree);
 547
 548 /* Return an rtx that refers to the value returned by a function
 549    in its original home.  This becomes invalid if any more code is emitted.  */
 550 extern rtx hard_function_value (tree, tree, int);
 551
 552 extern rtx prepare_call_address (rtx, rtx, rtx *, int, int);
 553
 554 extern bool shift_return_value (enum machine_mode, bool, rtx);
 555
 556 extern rtx expand_call (tree, rtx, int);
 557
 558 extern void fixup_tail_calls (void);
 559
 560 #ifdef TREE_CODE
 561 extern rtx expand_shift (enum tree_code, enum machine_mode, rtx, tree, rtx,
 562                          int);
 563 extern rtx expand_divmod (int, enum tree_code, enum machine_mode, rtx, rtx,
 564                           rtx, int);
 565 #endif
 566
 567 extern void locate_and_pad_parm (enum machine_mode, tree, int, int, tree,
 568                                  struct args_size *,
 569                                  struct locate_and_pad_arg_data *);
 570
 571 /* Return the CODE_LABEL rtx for a LABEL_DECL, creating it if necessary.  */
 572 extern rtx label_rtx (tree);
 573
 574 /* As label_rtx, but additionally the label is placed on the forced label
 575    list of its containing function (i.e. it is treated as reachable even
 576    if how is not obvious).  */
 577 extern rtx force_label_rtx (tree);
 578
 579 /* Indicate how an input argument register was promoted.  */
 580 extern rtx promoted_input_arg (unsigned int, enum machine_mode *, int *);
 581
 582 /* Return an rtx like arg but sans any constant terms.
 583    Returns the original rtx if it has no constant terms.
 584    The constant terms are added and stored via a second arg.  */
 585 extern rtx eliminate_constant_term (rtx, rtx *);
 586
 587 /* Convert arg to a valid memory address for specified machine mode,
 588    by emitting insns to perform arithmetic if nec.  */
 589 extern rtx memory_address (enum machine_mode, rtx);
 590
 591 /* Like `memory_address' but pretend `flag_force_addr' is 0.  */
 592 extern rtx memory_address_noforce (enum machine_mode, rtx);
 593
 594 /* Return a memory reference like MEMREF, but with its mode changed
 595    to MODE and its address changed to ADDR.
 596    (VOIDmode means don't change the mode.
 597    NULL for ADDR means don't change the address.)  */
 598 extern rtx change_address (rtx, enum machine_mode, rtx);
 599
 600 /* Return a memory reference like MEMREF, but with its mode changed
 601    to MODE and its address offset by OFFSET bytes.  */
 602 #define adjust_address(MEMREF, MODE, OFFSET) \
 603   adjust_address_1 (MEMREF, MODE, OFFSET, 1, 1)
 604
 605 /* Likewise, but the reference is not required to be valid.  */
 606 #define adjust_address_nv(MEMREF, MODE, OFFSET) \
 607   adjust_address_1 (MEMREF, MODE, OFFSET, 0, 1)
 608
 609 /* Return a memory reference like MEMREF, but with its mode changed
 610    to MODE and its address changed to ADDR, which is assumed to be
 611    increased by OFFSET bytes from MEMREF.  */
 612 #define adjust_automodify_address(MEMREF, MODE, ADDR, OFFSET) \
 613   adjust_automodify_address_1 (MEMREF, MODE, ADDR, OFFSET, 1)
 614
 615 /* Likewise, but the reference is not required to be valid.  */
 616 #define adjust_automodify_address_nv(MEMREF, MODE, ADDR, OFFSET) \
 617   adjust_automodify_address_1 (MEMREF, MODE, ADDR, OFFSET, 0)
 618
 619 extern rtx adjust_address_1 (rtx, enum machine_mode, HOST_WIDE_INT, int, int);
 620 extern rtx adjust_automodify_address_1 (rtx, enum machine_mode, rtx,
 621                                         HOST_WIDE_INT, int);
 622
 623 /* Return a memory reference like MEMREF, but whose address is changed by
 624    adding OFFSET, an RTX, to it.  POW2 is the highest power of two factor
 625    known to be in OFFSET (possibly 1).  */
 626 extern rtx offset_address (rtx, rtx, unsigned HOST_WIDE_INT);
 627
 628 /* Definitions from emit-rtl.c */
 629 #include "emit-rtl.h"
 630
 631 /* Return a memory reference like MEMREF, but with its mode widened to
 632    MODE and adjusted by OFFSET.  */
 633 extern rtx widen_memory_access (rtx, enum machine_mode, HOST_WIDE_INT);
 634
 635 /* Return a memory reference like MEMREF, but which is known to have a
 636    valid address.  */
 637 extern rtx validize_mem (rtx);
 638
 639 /* Given REF, a MEM, and T, either the type of X or the expression
 640    corresponding to REF, set the memory attributes.  OBJECTP is nonzero
 641    if we are making a new object of this type.  */
 642 extern void set_mem_attributes (rtx, tree, int);
 643
 644 /* Similar, except that BITPOS has not yet been applied to REF, so if
 645    we alter MEM_OFFSET according to T then we should subtract BITPOS
 646    expecting that it'll be added back in later.  */
 647 extern void set_mem_attributes_minus_bitpos (rtx, tree, int, HOST_WIDE_INT);
 648
 649 /* Assemble the static constant template for function entry trampolines.  */
 650 extern rtx assemble_trampoline_template (void);
 651
 652 /* Copy given rtx to a new temp reg and return that.  */
 653 extern rtx copy_to_reg (rtx);
 654
 655 /* Like copy_to_reg but always make the reg Pmode.  */
 656 extern rtx copy_addr_to_reg (rtx);
 657
 658 /* Like copy_to_reg but always make the reg the specified mode MODE.  */
 659 extern rtx copy_to_mode_reg (enum machine_mode, rtx);
 660
 661 /* Copy given rtx to given temp reg and return that.  */
 662 extern rtx copy_to_suggested_reg (rtx, rtx, enum machine_mode);
 663
 664 /* Copy a value to a register if it isn't already a register.
 665    Args are mode (in case value is a constant) and the value.  */
 666 extern rtx force_reg (enum machine_mode, rtx);
 667
 668 /* Return given rtx, copied into a new temp reg if it was in memory.  */
 669 extern rtx force_not_mem (rtx);
 670
 671 /* Return mode and signedness to use when object is promoted.  */
 672 extern enum machine_mode promote_mode (tree, enum machine_mode, int *, int);
 673
 674 /* Remove some bytes from the stack.  An rtx says how many.  */
 675 extern void adjust_stack (rtx);
 676
 677 /* Add some bytes to the stack.  An rtx says how many.  */
 678 extern void anti_adjust_stack (rtx);
 679
 680 /* This enum is used for the following two functions.  */
 681 enum save_level {SAVE_BLOCK, SAVE_FUNCTION, SAVE_NONLOCAL};
 682
 683 /* Save the stack pointer at the specified level.  */
 684 extern void emit_stack_save (enum save_level, rtx *, rtx);
 685
 686 /* Restore the stack pointer from a save area of the specified level.  */
 687 extern void emit_stack_restore (enum save_level, rtx, rtx);
 688
 689 /* Invoke emit_stack_save for the nonlocal_goto_save_area.  */
 690 extern void update_nonlocal_goto_save_area (void);
 691
 692 /* Allocate some space on the stack dynamically and return its address.  An rtx
 693    says how many bytes.  */
 694 extern rtx allocate_dynamic_stack_space (rtx, rtx, int);
 695
 696 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
 697    FIRST is a constant and size is a Pmode RTX.  These are offsets from the
 698    current stack pointer.  STACK_GROWS_DOWNWARD says whether to add or
 699    subtract from the stack.  If SIZE is constant, this is done
 700    with a fixed number of probes.  Otherwise, we must make a loop.  */
 701 extern void probe_stack_range (HOST_WIDE_INT, rtx);
 702
 703 /* Return an rtx that refers to the value returned by a library call
 704    in its original home.  This becomes invalid if any more code is emitted.  */
 705 extern rtx hard_libcall_value (enum machine_mode);
 706
 707 /* Return the mode desired by operand N of a particular bitfield
 708    insert/extract insn, or MAX_MACHINE_MODE if no such insn is
 709    available.  */
 710
 711 enum extraction_pattern { EP_insv, EP_extv, EP_extzv };
 712 extern enum machine_mode
 713 mode_for_extraction (enum extraction_pattern, int);
 714
 715 extern rtx store_bit_field (rtx, unsigned HOST_WIDE_INT,
 716                             unsigned HOST_WIDE_INT, enum machine_mode, rtx);
 717 extern rtx extract_bit_field (rtx, unsigned HOST_WIDE_INT,
 718                               unsigned HOST_WIDE_INT, int, rtx,
 719                               enum machine_mode, enum machine_mode);
 720 extern rtx expand_mult (enum machine_mode, rtx, rtx, rtx, int);
 721 extern bool const_mult_add_overflow_p (rtx, rtx, rtx, enum machine_mode, int);
 722 extern rtx expand_mult_add (rtx, rtx, rtx, rtx,enum machine_mode, int);
 723 extern rtx expand_mult_highpart_adjust (enum machine_mode, rtx, rtx, rtx, rtx, int);
 724
 725 extern rtx assemble_static_space (unsigned HOST_WIDE_INT);
 726 extern int safe_from_p (rtx, tree, int);
 727
 728 /* Call this once to initialize the contents of the optabs
 729    appropriately for the current target machine.  */
 730 extern void init_optabs (void);
 731 extern void init_all_optabs (void);
 732
 733 /* Call this to initialize an optab function entry.  */
 734 extern rtx init_one_libfunc (const char *);
 735
 736 extern void do_jump_by_parts_equality_rtx (rtx, rtx, rtx);
 737 extern void do_jump_by_parts_greater_rtx (enum machine_mode, int, rtx, rtx,
 738                                           rtx, rtx);
 739
 740 extern int vector_mode_valid_p (enum machine_mode);
 741
 742 #endif /* GCC_EXPR_H */