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 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 /* The default branch cost is 1.  */
  23 #ifndef BRANCH_COST
  24 #define BRANCH_COST 1
  25 #endif
  26
  27 /* Macros to access the slots of a QUEUED rtx.
  28    Here rather than in rtl.h because only the expansion pass
  29    should ever encounter a QUEUED.  */
  30
  31 /* The variable for which an increment is queued.  */
  32 #define QUEUED_VAR(P) XEXP (P, 0)
  33 /* If the increment has been emitted, this is the insn
  34    that does the increment.  It is zero before the increment is emitted.
  35    If more than one insn is emitted, this is the first insn.  */
  36 #define QUEUED_INSN(P) XEXP (P, 1)
  37 /* If a pre-increment copy has been generated, this is the copy
  38    (it is a temporary reg).  Zero if no copy made yet.  */
  39 #define QUEUED_COPY(P) XEXP (P, 2)
  40 /* This is the body to use for the insn to do the increment.
  41    It is used to emit the increment.  */
  42 #define QUEUED_BODY(P) XEXP (P, 3)
  43 /* Next QUEUED in the queue.  */
  44 #define QUEUED_NEXT(P) XEXP (P, 4)
  45
  46 /* This is the 4th arg to `expand_expr'.
  47    EXPAND_SUM means it is ok to return a PLUS rtx or MULT rtx.
  48    EXPAND_INITIALIZER is similar but also record any labels on forced_labels.
  49    EXPAND_CONST_ADDRESS means it is ok to return a MEM whose address
  50     is a constant that is not a legitimate address.
  51    EXPAND_WRITE means we are only going to write to the resulting rtx.  */
  52 enum expand_modifier {EXPAND_NORMAL, EXPAND_SUM, EXPAND_CONST_ADDRESS,
  53                         EXPAND_INITIALIZER, EXPAND_WRITE};
  54
  55 /* Prevent the compiler from deferring stack pops.  See
  56    inhibit_defer_pop for more information.  */
  57 #define NO_DEFER_POP (inhibit_defer_pop += 1)
  58
  59 /* Allow the compiler to defer stack pops.  See inhibit_defer_pop for
  60    more information.  */
  61 #define OK_DEFER_POP (inhibit_defer_pop -= 1)
  62 \f
  63 #ifdef TREE_CODE /* Don't lose if tree.h not included.  */
  64 /* Structure to record the size of a sequence of arguments
  65    as the sum of a tree-expression and a constant.  This structure is
  66    also used to store offsets from the stack, which might be negative,
  67    so the variable part must be ssizetype, not sizetype.  */
  68
  69 struct args_size
  70 {
  71   HOST_WIDE_INT constant;
  72   tree var;
  73 };
  74 #endif
  75
  76 /* Add the value of the tree INC to the `struct args_size' TO.  */
  77
  78 #define ADD_PARM_SIZE(TO, INC)                          \
  79 do {                                                    \
  80   tree inc = (INC);                                     \
  81   if (host_integerp (inc, 0))                           \
  82     (TO).constant += tree_low_cst (inc, 0);             \
  83   else if ((TO).var == 0)                               \
  84     (TO).var = convert (ssizetype, inc);                \
  85   else                                                  \
  86     (TO).var = size_binop (PLUS_EXPR, (TO).var,         \
  87                            convert (ssizetype, inc));   \
  88 } while (0)
  89
  90 #define SUB_PARM_SIZE(TO, DEC)                          \
  91 do {                                                    \
  92   tree dec = (DEC);                                     \
  93   if (host_integerp (dec, 0))                           \
  94     (TO).constant -= tree_low_cst (dec, 0);             \
  95   else if ((TO).var == 0)                               \
  96     (TO).var = size_binop (MINUS_EXPR, ssize_int (0),   \
  97                            convert (ssizetype, dec));   \
  98   else                                                  \
  99     (TO).var = size_binop (MINUS_EXPR, (TO).var,        \
 100                            convert (ssizetype, dec));   \
 101 } while (0)
 102
 103 /* Convert the implicit sum in a `struct args_size' into a tree
 104    of type ssizetype.  */
 105 #define ARGS_SIZE_TREE(SIZE)                                    \
 106 ((SIZE).var == 0 ? ssize_int ((SIZE).constant)                  \
 107  : size_binop (PLUS_EXPR, convert (ssizetype, (SIZE).var),      \
 108                ssize_int ((SIZE).constant)))
 109
 110 /* Convert the implicit sum in a `struct args_size' into an rtx.  */
 111 #define ARGS_SIZE_RTX(SIZE)                                     \
 112 ((SIZE).var == 0 ? GEN_INT ((SIZE).constant)                    \
 113  : expand_expr (ARGS_SIZE_TREE (SIZE), NULL_RTX, VOIDmode, 0))
 114
 115 /* Supply a default definition for FUNCTION_ARG_PADDING:
 116    usually pad upward, but pad short args downward on
 117    big-endian machines.  */
 118
 119 enum direction {none, upward, downward};  /* Value has this type.  */
 120
 121 #ifndef FUNCTION_ARG_PADDING
 122 #define FUNCTION_ARG_PADDING(MODE, TYPE)                                \
 123   (! BYTES_BIG_ENDIAN                                                   \
 124    ? upward                                                             \
 125    : (((MODE) == BLKmode                                                \
 126        ? ((TYPE) && TREE_CODE (TYPE_SIZE (TYPE)) == INTEGER_CST         \
 127           && int_size_in_bytes (TYPE) < (PARM_BOUNDARY / BITS_PER_UNIT)) \
 128        : GET_MODE_BITSIZE (MODE) < PARM_BOUNDARY)                       \
 129       ? downward : upward))
 130 #endif
 131
 132 /* Supply a default definition for FUNCTION_ARG_BOUNDARY.  Normally, we let
 133    FUNCTION_ARG_PADDING, which also pads the length, handle any needed
 134    alignment.  */
 135
 136 #ifndef FUNCTION_ARG_BOUNDARY
 137 #define FUNCTION_ARG_BOUNDARY(MODE, TYPE)       PARM_BOUNDARY
 138 #endif
 139
 140 /* Provide a default value for STRICT_ARGUMENT_NAMING.  */
 141 #ifndef STRICT_ARGUMENT_NAMING
 142 #define STRICT_ARGUMENT_NAMING 0
 143 #endif
 144
 145 /* Provide a default value for PRETEND_OUTGOING_VARARGS_NAMED.  */
 146 #ifdef SETUP_INCOMING_VARARGS
 147 #ifndef PRETEND_OUTGOING_VARARGS_NAMED
 148 #define PRETEND_OUTGOING_VARARGS_NAMED 1
 149 #endif
 150 #else
 151 /* It is an error to define PRETEND_OUTGOING_VARARGS_NAMED without
 152    defining SETUP_INCOMING_VARARGS.  */
 153 #define PRETEND_OUTGOING_VARARGS_NAMED 0
 154 #endif
 155
 156 /* Nonzero if we do not know how to pass TYPE solely in registers.
 157    We cannot do so in the following cases:
 158
 159    - if the type has variable size
 160    - if the type is marked as addressable (it is required to be constructed
 161      into the stack)
 162    - if the padding and mode of the type is such that a copy into a register
 163      would put it into the wrong part of the register.
 164
 165    Which padding can't be supported depends on the byte endianness.
 166
 167    A value in a register is implicitly padded at the most significant end.
 168    On a big-endian machine, that is the lower end in memory.
 169    So a value padded in memory at the upper end can't go in a register.
 170    For a little-endian machine, the reverse is true.  */
 171
 172 #ifndef MUST_PASS_IN_STACK
 173 #define MUST_PASS_IN_STACK(MODE,TYPE)                   \
 174   ((TYPE) != 0                                          \
 175    && (TREE_CODE (TYPE_SIZE (TYPE)) != INTEGER_CST      \
 176        || TREE_ADDRESSABLE (TYPE)                       \
 177        || ((MODE) == BLKmode                            \
 178            && ! ((TYPE) != 0 && TREE_CODE (TYPE_SIZE (TYPE)) == INTEGER_CST \
 179                  && 0 == (int_size_in_bytes (TYPE)      \
 180                           % (PARM_BOUNDARY / BITS_PER_UNIT))) \
 181            && (FUNCTION_ARG_PADDING (MODE, TYPE)        \
 182                == (BYTES_BIG_ENDIAN ? upward : downward)))))
 183 #endif
 184
 185 /* Nonzero if type TYPE should be returned in memory.
 186    Most machines can use the following default definition.  */
 187
 188 #ifndef RETURN_IN_MEMORY
 189 #define RETURN_IN_MEMORY(TYPE) (TYPE_MODE (TYPE) == BLKmode)
 190 #endif
 191
 192 /* Supply a default definition of STACK_SAVEAREA_MODE for emit_stack_save.
 193    Normally move_insn, so Pmode stack pointer.  */
 194
 195 #ifndef STACK_SAVEAREA_MODE
 196 #define STACK_SAVEAREA_MODE(LEVEL) Pmode
 197 #endif
 198
 199 /* Supply a default definition of STACK_SIZE_MODE for
 200    allocate_dynamic_stack_space.  Normally PLUS/MINUS, so word_mode.  */
 201
 202 #ifndef STACK_SIZE_MODE
 203 #define STACK_SIZE_MODE word_mode
 204 #endif
 205
 206 /* Provide default values for the macros controlling stack checking.  */
 207
 208 #ifndef STACK_CHECK_BUILTIN
 209 #define STACK_CHECK_BUILTIN 0
 210 #endif
 211
 212 /* The default interval is one page.  */
 213 #ifndef STACK_CHECK_PROBE_INTERVAL
 214 #define STACK_CHECK_PROBE_INTERVAL 4096
 215 #endif
 216
 217 /* The default is to do a store into the stack.  */
 218 #ifndef STACK_CHECK_PROBE_LOAD
 219 #define STACK_CHECK_PROBE_LOAD 0
 220 #endif
 221
 222 /* This value is arbitrary, but should be sufficient for most machines.  */
 223 #ifndef STACK_CHECK_PROTECT
 224 #define STACK_CHECK_PROTECT (75 * UNITS_PER_WORD)
 225 #endif
 226
 227 /* Make the maximum frame size be the largest we can and still only need
 228    one probe per function.  */
 229 #ifndef STACK_CHECK_MAX_FRAME_SIZE
 230 #define STACK_CHECK_MAX_FRAME_SIZE \
 231   (STACK_CHECK_PROBE_INTERVAL - UNITS_PER_WORD)
 232 #endif
 233
 234 /* This is arbitrary, but should be large enough everywhere.  */
 235 #ifndef STACK_CHECK_FIXED_FRAME_SIZE
 236 #define STACK_CHECK_FIXED_FRAME_SIZE (4 * UNITS_PER_WORD)
 237 #endif
 238
 239 /* Provide a reasonable default for the maximum size of an object to
 240    allocate in the fixed frame.  We may need to be able to make this
 241    controllable by the user at some point.  */
 242 #ifndef STACK_CHECK_MAX_VAR_SIZE
 243 #define STACK_CHECK_MAX_VAR_SIZE (STACK_CHECK_MAX_FRAME_SIZE / 100)
 244 #endif
 245 \f
 246 /* Functions from optabs.c, commonly used, and without need for the optabs
 247    tables:  */
 248
 249 /* Passed to expand_simple_binop and expand_binop to say which options
 250    to try to use if the requested operation can't be open-coded on the
 251    requisite mode.  Either OPTAB_LIB or OPTAB_LIB_WIDEN says try using
 252    a library call.  Either OPTAB_WIDEN or OPTAB_LIB_WIDEN says try
 253    using a wider mode.  OPTAB_MUST_WIDEN says try widening and don't
 254    try anything else.  */
 255
 256 enum optab_methods
 257 {
 258   OPTAB_DIRECT,
 259   OPTAB_LIB,
 260   OPTAB_WIDEN,
 261   OPTAB_LIB_WIDEN,
 262   OPTAB_MUST_WIDEN
 263 };
 264
 265 /* Generate code for a simple binary or unary operation.  "Simple" in
 266    this case means "can be unambiguously described by a (mode, code)
 267    pair and mapped to a single optab."  */
 268 extern rtx expand_simple_binop PARAMS ((enum machine_mode, enum rtx_code, rtx,
 269                                         rtx, rtx, int, enum optab_methods));
 270 extern rtx expand_simple_unop PARAMS ((enum machine_mode, enum rtx_code,
 271                                        rtx, rtx, int));
 272
 273 /* Report whether the machine description contains an insn which can
 274    perform the operation described by CODE and MODE.  */
 275 extern int have_insn_for PARAMS ((enum rtx_code, enum machine_mode));
 276
 277 /* Emit code to make a call to a constant function or a library call.  */
 278 extern void emit_libcall_block PARAMS ((rtx, rtx, rtx, rtx));
 279
 280 /* Create but don't emit one rtl instruction to perform certain operations.
 281    Modes must match; operands must meet the operation's predicates.
 282    Likewise for subtraction and for just copying.
 283    These do not call protect_from_queue; caller must do so.  */
 284 extern rtx gen_add2_insn PARAMS ((rtx, rtx));
 285 extern rtx gen_add3_insn PARAMS ((rtx, rtx, rtx));
 286 extern rtx gen_sub2_insn PARAMS ((rtx, rtx));
 287 extern rtx gen_sub3_insn PARAMS ((rtx, rtx, rtx));
 288 extern rtx gen_move_insn PARAMS ((rtx, rtx));
 289 extern int have_add2_insn PARAMS ((rtx, rtx));
 290 extern int have_sub2_insn PARAMS ((rtx, rtx));
 291
 292 /* Emit a pair of rtl insns to compare two rtx's and to jump
 293    to a label if the comparison is true.  */
 294 extern void emit_cmp_and_jump_insns PARAMS ((rtx, rtx, enum rtx_code, rtx,
 295                                              enum machine_mode, int, rtx));
 296
 297 /* Generate code to indirectly jump to a location given in the rtx LOC.  */
 298 extern void emit_indirect_jump PARAMS ((rtx));
 299
 300 #ifdef HAVE_conditional_move
 301 /* Emit a conditional move operation.  */
 302 rtx emit_conditional_move PARAMS ((rtx, enum rtx_code, rtx, rtx,
 303                                    enum machine_mode, rtx, rtx,
 304                                    enum machine_mode, int));
 305
 306 /* Return non-zero if the conditional move is supported.  */
 307 int can_conditionally_move_p PARAMS ((enum machine_mode mode));
 308
 309 #endif
 310
 311 \f
 312 /* Functions from expmed.c:  */
 313
 314 /* Arguments MODE, RTX: return an rtx for the negation of that value.
 315    May emit insns.  */
 316 extern rtx negate_rtx PARAMS ((enum machine_mode, rtx));
 317
 318 /* Expand a logical AND operation.  */
 319 extern rtx expand_and PARAMS ((enum machine_mode, rtx, rtx, rtx));
 320
 321 /* Emit a store-flag operation.  */
 322 extern rtx emit_store_flag PARAMS ((rtx, enum rtx_code, rtx, rtx,
 323                                     enum machine_mode, int, int));
 324
 325 /* Like emit_store_flag, but always succeeds.  */
 326 extern rtx emit_store_flag_force PARAMS ((rtx, enum rtx_code, rtx, rtx,
 327                                           enum machine_mode, int, int));
 328
 329 /* Functions from loop.c:  */
 330
 331 /* Given an insn and condition, return a canonical description of
 332    the test being made.  */
 333 extern rtx canonicalize_condition PARAMS ((rtx, rtx, int, rtx *, rtx));
 334
 335 /* Given a JUMP_INSN, return a canonical description of the test
 336    being made.  */
 337 extern rtx get_condition PARAMS ((rtx, rtx *));
 338
 339 /* Generate a conditional trap instruction.  */
 340 extern rtx gen_cond_trap PARAMS ((enum rtx_code, rtx, rtx, rtx));
 341 \f
 342 /* Functions from builtins.c:  */
 343 extern rtx expand_builtin PARAMS ((tree, rtx, rtx, enum machine_mode, int));
 344 extern void std_expand_builtin_va_start PARAMS ((int, tree, rtx));
 345 extern rtx std_expand_builtin_va_arg PARAMS ((tree, tree));
 346 extern rtx expand_builtin_va_arg PARAMS ((tree, tree));
 347 extern void default_init_builtins PARAMS ((void));
 348 extern rtx default_expand_builtin PARAMS ((tree, rtx, rtx,
 349                                            enum machine_mode, int));
 350 extern void expand_builtin_setjmp_setup PARAMS ((rtx, rtx));
 351 extern void expand_builtin_setjmp_receiver PARAMS ((rtx));
 352 extern void expand_builtin_longjmp PARAMS ((rtx, rtx));
 353 extern rtx expand_builtin_saveregs PARAMS ((void));
 354 extern void expand_builtin_trap PARAMS ((void));
 355 extern HOST_WIDE_INT get_varargs_alias_set PARAMS ((void));
 356 extern HOST_WIDE_INT get_frame_alias_set PARAMS ((void));
 357 extern void record_base_value           PARAMS ((unsigned int, rtx, int));
 358 extern void record_alias_subset         PARAMS ((HOST_WIDE_INT,
 359                                                  HOST_WIDE_INT));
 360 extern HOST_WIDE_INT new_alias_set              PARAMS ((void));
 361 extern int can_address_p                PARAMS ((tree));
 362 \f
 363 /* Functions from expr.c:  */
 364
 365 /* This is run once per compilation to set up which modes can be used
 366    directly in memory and to initialize the block move optab.  */
 367 extern void init_expr_once PARAMS ((void));
 368
 369 /* This is run at the start of compiling a function.  */
 370 extern void init_expr PARAMS ((void));
 371
 372 /* This function is run once to initialize stor-layout.c.  */
 373
 374 extern void init_stor_layout_once PARAMS ((void));
 375
 376 /* This is run at the end of compiling a function.  */
 377 extern void finish_expr_for_function PARAMS ((void));
 378
 379 /* Use protect_from_queue to convert a QUEUED expression
 380    into something that you can put immediately into an instruction.  */
 381 extern rtx protect_from_queue PARAMS ((rtx, int));
 382
 383 /* Perform all the pending incrementations.  */
 384 extern void emit_queue PARAMS ((void));
 385
 386 /* Tell if something has a queued subexpression.  */
 387 extern int queued_subexp_p PARAMS ((rtx));
 388
 389 /* Emit some rtl insns to move data between rtx's, converting machine modes.
 390    Both modes must be floating or both fixed.  */
 391 extern void convert_move PARAMS ((rtx, rtx, int));
 392
 393 /* Convert an rtx to specified machine mode and return the result.  */
 394 extern rtx convert_to_mode PARAMS ((enum machine_mode, rtx, int));
 395
 396 /* Convert an rtx to MODE from OLDMODE and return the result.  */
 397 extern rtx convert_modes PARAMS ((enum machine_mode, enum machine_mode,
 398                                   rtx, int));
 399
 400 /* Emit code to move a block Y to a block X.  */
 401 extern rtx emit_block_move PARAMS ((rtx, rtx, rtx));
 402
 403 /* Copy all or part of a value X into registers starting at REGNO.
 404    The number of registers to be filled is NREGS.  */
 405 extern void move_block_to_reg PARAMS ((int, rtx, int, enum machine_mode));
 406
 407 /* Copy all or part of a BLKmode value X out of registers starting at REGNO.
 408    The number of registers to be filled is NREGS.  */
 409 extern void move_block_from_reg PARAMS ((int, rtx, int, int));
 410
 411 /* Load a BLKmode value into non-consecutive registers represented by a
 412    PARALLEL.  */
 413 extern void emit_group_load PARAMS ((rtx, rtx, int));
 414
 415 /* Store a BLKmode value from non-consecutive registers represented by a
 416    PARALLEL.  */
 417 extern void emit_group_store PARAMS ((rtx, rtx, int));
 418
 419 #ifdef TREE_CODE
 420 /* Copy BLKmode object from a set of registers.  */
 421 extern rtx copy_blkmode_from_reg PARAMS ((rtx,rtx,tree));
 422 #endif
 423
 424 /* Mark REG as holding a parameter for the next CALL_INSN.  */
 425 extern void use_reg PARAMS ((rtx *, rtx));
 426
 427 /* Mark NREGS consecutive regs, starting at REGNO, as holding parameters
 428    for the next CALL_INSN.  */
 429 extern void use_regs PARAMS ((rtx *, int, int));
 430
 431 /* Mark a PARALLEL as holding a parameter for the next CALL_INSN.  */
 432 extern void use_group_regs PARAMS ((rtx *, rtx));
 433
 434 /* Write zeros through the storage of OBJECT.
 435    If OBJECT has BLKmode, SIZE is its length in bytes.  */
 436 extern rtx clear_storage PARAMS ((rtx, rtx));
 437
 438 /* Return non-zero if it is desirable to store LEN bytes generated by
 439    CONSTFUN with several move instructions by store_by_pieces
 440    function.  CONSTFUNDATA is a pointer which will be passed as argument
 441    in every CONSTFUN call.
 442    ALIGN is maximum alignment we can assume.  */
 443 extern int can_store_by_pieces PARAMS ((unsigned HOST_WIDE_INT,
 444                                         rtx (*) (PTR, HOST_WIDE_INT,
 445                                                  enum machine_mode),
 446                                         PTR, unsigned int));
 447
 448 /* Generate several move instructions to store LEN bytes generated by
 449    CONSTFUN to block TO.  (A MEM rtx with BLKmode).  CONSTFUNDATA is a
 450    pointer which will be passed as argument in every CONSTFUN call.
 451    ALIGN is maximum alignment we can assume.  */
 452 extern void store_by_pieces PARAMS ((rtx, unsigned HOST_WIDE_INT,
 453                                      rtx (*) (PTR, HOST_WIDE_INT,
 454                                               enum machine_mode),
 455                                      PTR, unsigned int));
 456
 457 /* Emit insns to set X from Y.  */
 458 extern rtx emit_move_insn PARAMS ((rtx, rtx));
 459
 460 /* Emit insns to set X from Y, with no frills.  */
 461 extern rtx emit_move_insn_1 PARAMS ((rtx, rtx));
 462
 463 /* Push a block of length SIZE (perhaps variable)
 464    and return an rtx to address the beginning of the block.  */
 465 extern rtx push_block PARAMS ((rtx, int, int));
 466
 467 #ifdef TREE_CODE
 468 /* Generate code to push something onto the stack, given its mode and type.  */
 469 extern void emit_push_insn PARAMS ((rtx, enum machine_mode, tree, rtx,
 470                                     unsigned int, int, rtx, int, rtx, rtx,
 471                                     int, rtx));
 472
 473 /* Expand an assignment that stores the value of FROM into TO.  */
 474 extern rtx expand_assignment PARAMS ((tree, tree, int, int));
 475
 476 /* Generate code for computing expression EXP,
 477    and storing the value into TARGET.
 478    If SUGGEST_REG is nonzero, copy the value through a register
 479    and return that register, if that is possible.  */
 480 extern rtx store_expr PARAMS ((tree, rtx, int));
 481 #endif
 482
 483 /* Given an rtx that may include add and multiply operations,
 484    generate them as insns and return a pseudo-reg containing the value.
 485    Useful after calling expand_expr with 1 as sum_ok.  */
 486 extern rtx force_operand PARAMS ((rtx, rtx));
 487
 488 /* Return an object on the placeholder list that matches EXP, a
 489    PLACEHOLDER_EXPR.  An object "matches" if it is of the type of the
 490    PLACEHOLDER_EXPR or a pointer type to it.  For further information, see
 491    tree.def.  If no such object is found, abort.  If PLIST is nonzero, it is
 492    a location which initially points to a starting location in the
 493    placeholder list (zero means start of the list) and where a pointer into
 494    the placeholder list at which the object is found is placed.  */
 495 extern tree find_placeholder PARAMS ((tree, tree *));
 496
 497 /* Generate code for computing expression EXP.
 498    An rtx for the computed value is returned.  The value is never null.
 499    In the case of a void EXP, const0_rtx is returned.  */
 500 extern rtx expand_expr PARAMS ((tree, rtx, enum machine_mode,
 501                                 enum expand_modifier));
 502
 503 /* At the start of a function, record that we have no previously-pushed
 504    arguments waiting to be popped.  */
 505 extern void init_pending_stack_adjust PARAMS ((void));
 506
 507 /* When exiting from function, if safe, clear out any pending stack adjust
 508    so the adjustment won't get done.  */
 509 extern void clear_pending_stack_adjust PARAMS ((void));
 510
 511 /* Pop any previously-pushed arguments that have not been popped yet.  */
 512 extern void do_pending_stack_adjust PARAMS ((void));
 513
 514 #ifdef TREE_CODE
 515 /* Return the tree node and offset if a given argument corresponds to
 516    a string constant.  */
 517 extern tree string_constant PARAMS ((tree, tree *));
 518
 519 /* Generate code to evaluate EXP and jump to LABEL if the value is zero.  */
 520 extern void jumpifnot PARAMS ((tree, rtx));
 521
 522 /* Generate code to evaluate EXP and jump to LABEL if the value is nonzero.  */
 523 extern void jumpif PARAMS ((tree, rtx));
 524
 525 /* Generate code to evaluate EXP and jump to IF_FALSE_LABEL if
 526    the result is zero, or IF_TRUE_LABEL if the result is one.  */
 527 extern void do_jump PARAMS ((tree, rtx, rtx));
 528 #endif
 529
 530 /* Generate rtl to compare two rtx's, will call emit_cmp_insn.  */
 531 extern rtx compare_from_rtx PARAMS ((rtx, rtx, enum rtx_code, int,
 532                                      enum machine_mode, rtx));
 533 extern void do_compare_rtx_and_jump PARAMS ((rtx, rtx, enum rtx_code, int,
 534                                              enum machine_mode, rtx,
 535                                              rtx, rtx));
 536
 537 /* Two different ways of generating switch statements.  */
 538 extern int try_casesi    PARAMS ((tree, tree, tree, tree, rtx, rtx));
 539 extern int try_tablejump PARAMS ((tree, tree, tree, tree, rtx, rtx));
 540
 541 /* Smallest number of adjacent cases before we use a jump table.
 542    XXX Should be a target hook.  */
 543 extern unsigned int case_values_threshold PARAMS ((void));
 544
 545 \f
 546 #ifdef TREE_CODE
 547 /* rtl.h and tree.h were included.  */
 548 /* Return an rtx for the size in bytes of the value of an expr.  */
 549 extern rtx expr_size PARAMS ((tree));
 550
 551 extern rtx lookup_static_chain PARAMS ((tree));
 552
 553 /* Convert a stack slot address ADDR valid in function FNDECL
 554    into an address valid in this function (using a static chain).  */
 555 extern rtx fix_lexical_addr PARAMS ((rtx, tree));
 556
 557 /* Return the address of the trampoline for entering nested fn FUNCTION.  */
 558 extern rtx trampoline_address PARAMS ((tree));
 559
 560 /* Return an rtx that refers to the value returned by a function
 561    in its original home.  This becomes invalid if any more code is emitted.  */
 562 extern rtx hard_function_value PARAMS ((tree, tree, int));
 563
 564 extern rtx prepare_call_address PARAMS ((rtx, tree, rtx *, int, int));
 565
 566 extern rtx expand_call PARAMS ((tree, rtx, int));
 567
 568 extern rtx expand_shift PARAMS ((enum tree_code, enum machine_mode, rtx, tree,
 569                                  rtx, int));
 570 extern rtx expand_divmod PARAMS ((int, enum tree_code, enum machine_mode, rtx,
 571                                   rtx, rtx, int));
 572 extern void locate_and_pad_parm PARAMS ((enum machine_mode, tree, int, tree,
 573                                          struct args_size *,
 574                                          struct args_size *,
 575                                          struct args_size *,
 576                                          struct args_size *));
 577 extern rtx expand_inline_function PARAMS ((tree, tree, rtx, int, tree, rtx));
 578
 579 /* Return the CODE_LABEL rtx for a LABEL_DECL, creating it if necessary.  */
 580 extern rtx label_rtx PARAMS ((tree));
 581 #endif
 582
 583 /* Indicate how an input argument register was promoted.  */
 584 extern rtx promoted_input_arg PARAMS ((unsigned int, enum machine_mode *,
 585                                        int *));
 586
 587 /* Return an rtx like arg but sans any constant terms.
 588    Returns the original rtx if it has no constant terms.
 589    The constant terms are added and stored via a second arg.  */
 590 extern rtx eliminate_constant_term PARAMS ((rtx, rtx *));
 591
 592 /* Convert arg to a valid memory address for specified machine mode,
 593    by emitting insns to perform arithmetic if nec.  */
 594 extern rtx memory_address PARAMS ((enum machine_mode, rtx));
 595
 596 /* Like `memory_address' but pretent `flag_force_addr' is 0.  */
 597 extern rtx memory_address_noforce PARAMS ((enum machine_mode, rtx));
 598
 599 /* Set the alias set of MEM to SET.  */
 600 extern void set_mem_alias_set PARAMS ((rtx, HOST_WIDE_INT));
 601
 602 /* Set the alignment of MEM to ALIGN bits.  */
 603 extern void set_mem_align PARAMS ((rtx, unsigned int));
 604
 605 /* Set the expr for MEM to EXPR.  */
 606 extern void set_mem_expr PARAMS ((rtx, tree));
 607
 608 /* Set the offset for MEM to OFFSET.  */
 609 extern void set_mem_offset PARAMS ((rtx, rtx));
 610
 611 /* Return a memory reference like MEMREF, but with its mode changed
 612    to MODE and its address changed to ADDR.
 613    (VOIDmode means don't change the mode.
 614    NULL for ADDR means don't change the address.)  */
 615 extern rtx change_address PARAMS ((rtx, enum machine_mode, rtx));
 616
 617 /* Return a memory reference like MEMREF, but with its mode changed
 618    to MODE and its address offset by OFFSET bytes.  */
 619 #define adjust_address(MEMREF, MODE, OFFSET) \
 620   adjust_address_1 (MEMREF, MODE, OFFSET, 1, 1)
 621
 622 /* Likewise, but the reference is not required to be valid.  */
 623 #define adjust_address_nv(MEMREF, MODE, OFFSET) \
 624   adjust_address_1 (MEMREF, MODE, OFFSET, 0, 1)
 625
 626 /* Return a memory reference like MEMREF, but with its mode changed
 627    to MODE and its address changed to ADDR, which is assumed to be
 628    increased by OFFSET bytes from MEMREF.  */
 629 #define adjust_automodify_address(MEMREF, MODE, ADDR, OFFSET) \
 630   adjust_automodify_address_1 (MEMREF, MODE, ADDR, OFFSET, 1)
 631
 632 /* Likewise, but the reference is not required to be valid.  */
 633 #define adjust_automodify_address_nv(MEMREF, MODE, ADDR, OFFSET) \
 634   adjust_automodify_address_1 (MEMREF, MODE, ADDR, OFFSET, 0)
 635
 636 extern rtx adjust_address_1 PARAMS ((rtx, enum machine_mode, HOST_WIDE_INT,
 637                                      int, int));
 638 extern rtx adjust_automodify_address_1 PARAMS ((rtx, enum machine_mode,
 639                                                 rtx, HOST_WIDE_INT, int));
 640
 641 /* Return a memory reference like MEMREF, but whose address is changed by
 642    adding OFFSET, an RTX, to it.  POW2 is the highest power of two factor
 643    known to be in OFFSET (possibly 1).  */
 644 extern rtx offset_address PARAMS ((rtx, rtx, HOST_WIDE_INT));
 645
 646 /* Return a memory reference like MEMREF, but with its address changed to
 647    ADDR.  The caller is asserting that the actual piece of memory pointed
 648    to is the same, just the form of the address is being changed, such as
 649    by putting something into a register.  */
 650 extern rtx replace_equiv_address PARAMS ((rtx, rtx));
 651
 652 /* Likewise, but the reference is not required to be valid.  */
 653 extern rtx replace_equiv_address_nv PARAMS ((rtx, rtx));
 654
 655 /* Return a memory reference like MEMREF, but with its mode widened to
 656    MODE and adjusted by OFFSET.  */
 657 extern rtx widen_memory_access PARAMS ((rtx, enum machine_mode, HOST_WIDE_INT));
 658
 659 /* Return a memory reference like MEMREF, but which is known to have a
 660    valid address.  */
 661 extern rtx validize_mem PARAMS ((rtx));
 662
 663 #ifdef TREE_CODE
 664 /* Given REF, either a MEM or a REG, and T, either the type of X or
 665    the expression corresponding to REF, set RTX_UNCHANGING_P if
 666    appropriate.  */
 667 extern void maybe_set_unchanging PARAMS ((rtx, tree));
 668
 669 /* Given REF, a MEM, and T, either the type of X or the expression
 670    corresponding to REF, set the memory attributes.  OBJECTP is nonzero
 671    if we are making a new object of this type.  */
 672 extern void set_mem_attributes PARAMS ((rtx, tree, int));
 673 #endif
 674
 675 /* Assemble the static constant template for function entry trampolines.  */
 676 extern rtx assemble_trampoline_template PARAMS ((void));
 677
 678 /* Given rtx, return new rtx whose address won't be affected by
 679    any side effects.  It has been copied to a new temporary reg.  */
 680 extern rtx stabilize PARAMS ((rtx));
 681
 682 /* Given an rtx, copy all regs it refers to into new temps
 683    and return a modified copy that refers to the new temps.  */
 684 extern rtx copy_all_regs PARAMS ((rtx));
 685
 686 /* Copy given rtx to a new temp reg and return that.  */
 687 extern rtx copy_to_reg PARAMS ((rtx));
 688
 689 /* Like copy_to_reg but always make the reg Pmode.  */
 690 extern rtx copy_addr_to_reg PARAMS ((rtx));
 691
 692 /* Like copy_to_reg but always make the reg the specified mode MODE.  */
 693 extern rtx copy_to_mode_reg PARAMS ((enum machine_mode, rtx));
 694
 695 /* Copy given rtx to given temp reg and return that.  */
 696 extern rtx copy_to_suggested_reg PARAMS ((rtx, rtx, enum machine_mode));
 697
 698 /* Copy a value to a register if it isn't already a register.
 699    Args are mode (in case value is a constant) and the value.  */
 700 extern rtx force_reg PARAMS ((enum machine_mode, rtx));
 701
 702 /* Return given rtx, copied into a new temp reg if it was in memory.  */
 703 extern rtx force_not_mem PARAMS ((rtx));
 704
 705 #ifdef TREE_CODE
 706 /* Return mode and signedness to use when object is promoted.  */
 707 extern enum machine_mode promote_mode PARAMS ((tree, enum machine_mode,
 708                                                int *, int));
 709 #endif
 710
 711 /* Remove some bytes from the stack.  An rtx says how many.  */
 712 extern void adjust_stack PARAMS ((rtx));
 713
 714 /* Add some bytes to the stack.  An rtx says how many.  */
 715 extern void anti_adjust_stack PARAMS ((rtx));
 716
 717 /* This enum is used for the following two functions.  */
 718 enum save_level {SAVE_BLOCK, SAVE_FUNCTION, SAVE_NONLOCAL};
 719
 720 /* Save the stack pointer at the specified level.  */
 721 extern void emit_stack_save PARAMS ((enum save_level, rtx *, rtx));
 722
 723 /* Restore the stack pointer from a save area of the specified level.  */
 724 extern void emit_stack_restore PARAMS ((enum save_level, rtx, rtx));
 725
 726 /* Allocate some space on the stack dynamically and return its address.  An rtx
 727    says how many bytes.  */
 728 extern rtx allocate_dynamic_stack_space PARAMS ((rtx, rtx, int));
 729
 730 /* Probe a range of stack addresses from FIRST to FIRST+SIZE, inclusive.
 731    FIRST is a constant and size is a Pmode RTX.  These are offsets from the
 732    current stack pointer.  STACK_GROWS_DOWNWARD says whether to add or
 733    subtract from the stack.  If SIZE is constant, this is done
 734    with a fixed number of probes.  Otherwise, we must make a loop.  */
 735 extern void probe_stack_range PARAMS ((HOST_WIDE_INT, rtx));
 736
 737 /* Return an rtx that refers to the value returned by a library call
 738    in its original home.  This becomes invalid if any more code is emitted.  */
 739 extern rtx hard_libcall_value PARAMS ((enum machine_mode));
 740
 741 /* Given an rtx, return an rtx for a value rounded up to a multiple
 742    of STACK_BOUNDARY / BITS_PER_UNIT.  */
 743 extern rtx round_push PARAMS ((rtx));
 744
 745 /* Return the mode desired by operand N of a particular bitfield
 746    insert/extract insn, or MAX_MACHINE_MODE if no such insn is
 747    available.  */
 748
 749 enum extraction_pattern { EP_insv, EP_extv, EP_extzv };
 750 extern enum machine_mode
 751 mode_for_extraction PARAMS ((enum extraction_pattern, int));
 752
 753 extern rtx store_bit_field PARAMS ((rtx, unsigned HOST_WIDE_INT,
 754                                     unsigned HOST_WIDE_INT,
 755                                     enum machine_mode, rtx, HOST_WIDE_INT));
 756 extern rtx extract_bit_field PARAMS ((rtx, unsigned HOST_WIDE_INT,
 757                                       unsigned HOST_WIDE_INT, int, rtx,
 758                                       enum machine_mode, enum machine_mode,
 759                                       HOST_WIDE_INT));
 760 extern rtx expand_mult PARAMS ((enum machine_mode, rtx, rtx, rtx, int));
 761 extern bool const_mult_add_overflow_p PARAMS ((rtx, rtx, rtx, enum machine_mode, int));
 762 extern rtx expand_mult_add PARAMS ((rtx, rtx, rtx, rtx,enum machine_mode, int));
 763 extern rtx expand_mult_highpart_adjust PARAMS ((enum machine_mode, rtx, rtx, rtx, rtx, int));
 764
 765 extern rtx assemble_static_space PARAMS ((int));
 766
 767 /* Hook called by expand_expr for language-specific tree codes.
 768    It is up to the language front end to install a hook
 769    if it has any such codes that expand_expr needs to know about.  */
 770 extern rtx (*lang_expand_expr) PARAMS ((union tree_node *, rtx,
 771                                         enum machine_mode,
 772                                         enum expand_modifier modifier));
 773
 774 extern int safe_from_p PARAMS ((rtx, tree, int));
 775
 776 /* Call this once to initialize the contents of the optabs
 777    appropriately for the current target machine.  */
 778 extern void init_optabs                         PARAMS ((void));
 779 extern void init_all_optabs                     PARAMS ((void));
 780
 781 /* Call this to initialize an optab function entry.  */
 782 extern rtx init_one_libfunc                     PARAMS ((const char *));
 783
 784 extern void do_jump_by_parts_equality_rtx       PARAMS ((rtx, rtx, rtx));
 785 extern void do_jump_by_parts_greater_rtx        PARAMS ((enum machine_mode,
 786                                                          int, rtx, rtx, rtx,
 787                                                          rtx));
 788
 789 #ifdef TREE_CODE   /* Don't lose if tree.h not included.  */
 790 extern void mark_seen_cases                     PARAMS ((tree, unsigned char *,
 791                                                          HOST_WIDE_INT, int));
 792 #endif