Annotation of gcc/emit-rtl.c, revision 1.1.1.1

1.1       root        1: /* Emit RTL for the GNU C-Compiler expander.
                      2:    Copyright (C) 1987, 1988, 1992 Free Software Foundation, Inc.
                      3: 
                      4: This file is part of GNU CC.
                      5: 
                      6: GNU CC is free software; you can redistribute it and/or modify
                      7: it under the terms of the GNU General Public License as published by
                      8: the Free Software Foundation; either version 2, or (at your option)
                      9: any later version.
                     10: 
                     11: GNU CC is distributed in the hope that it will be useful,
                     12: but WITHOUT ANY WARRANTY; without even the implied warranty of
                     13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                     14: GNU General Public License for more details.
                     15: 
                     16: You should have received a copy of the GNU General Public License
                     17: along with GNU CC; see the file COPYING.  If not, write to
                     18: the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
                     19: 
                     20: 
                     21: /* Middle-to-low level generation of rtx code and insns.
                     22: 
                     23:    This file contains the functions `gen_rtx', `gen_reg_rtx'
                     24:    and `gen_label_rtx' that are the usual ways of creating rtl
                     25:    expressions for most purposes.
                     26: 
                     27:    It also has the functions for creating insns and linking
                     28:    them in the doubly-linked chain.
                     29: 
                     30:    The patterns of the insns are created by machine-dependent
                     31:    routines in insn-emit.c, which is generated automatically from
                     32:    the machine description.  These routines use `gen_rtx' to make
                     33:    the individual rtx's of the pattern; what is machine dependent
                     34:    is the kind of rtx's they make and what arguments they use.  */
                     35: 
                     36: #include "config.h"
                     37: #include <stdio.h>
                     38: #include "gvarargs.h"
                     39: #include "rtl.h"
                     40: #include "flags.h"
                     41: #include "function.h"
                     42: #include "expr.h"
                     43: #include "regs.h"
                     44: #include "insn-config.h"
                     45: #include "real.h"
                     46: 
                     47: /* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function.
                     48:    After rtl generation, it is 1 plus the largest register number used.  */
                     49: 
                     50: int reg_rtx_no = LAST_VIRTUAL_REGISTER + 1;
                     51: 
                     52: /* This is *not* reset after each function.  It gives each CODE_LABEL
                     53:    in the entire compilation a unique label number.  */
                     54: 
                     55: static int label_num = 1;
                     56: 
                     57: /* Lowest label number in current function.  */
                     58: 
                     59: static int first_label_num;
                     60: 
                     61: /* Highest label number in current function.
                     62:    Zero means use the value of label_num instead.
                     63:    This is nonzero only when belatedly compiling an inline function.  */
                     64: 
                     65: static int last_label_num;
                     66: 
                     67: /* Value label_num had when set_new_first_and_last_label_number was called.
                     68:    If label_num has not changed since then, last_label_num is valid.  */
                     69: 
                     70: static int base_label_num;
                     71: 
                     72: /* Nonzero means do not generate NOTEs for source line numbers.  */
                     73: 
                     74: static int no_line_numbers;
                     75: 
                     76: /* Commonly used rtx's, so that we only need space for one copy.
                     77:    These are initialized once for the entire compilation.
                     78:    All of these except perhaps the floating-point CONST_DOUBLEs
                     79:    are unique; no other rtx-object will be equal to any of these.  */
                     80: 
                     81: rtx pc_rtx;                    /* (PC) */
                     82: rtx cc0_rtx;                   /* (CC0) */
                     83: rtx cc1_rtx;                   /* (CC1) (not actually used nowadays) */
                     84: rtx const0_rtx;                        /* (CONST_INT 0) */
                     85: rtx const1_rtx;                        /* (CONST_INT 1) */
                     86: rtx const2_rtx;                        /* (CONST_INT 2) */
                     87: rtx constm1_rtx;               /* (CONST_INT -1) */
                     88: rtx const_true_rtx;            /* (CONST_INT STORE_FLAG_VALUE) */
                     89: 
                     90: /* We record floating-point CONST_DOUBLEs in each floating-point mode for
                     91:    the values of 0, 1, and 2.  For the integer entries and VOIDmode, we
                     92:    record a copy of const[012]_rtx.  */
                     93: 
                     94: rtx const_tiny_rtx[3][(int) MAX_MACHINE_MODE];
                     95: 
                     96: REAL_VALUE_TYPE dconst0;
                     97: REAL_VALUE_TYPE dconst1;
                     98: REAL_VALUE_TYPE dconst2;
                     99: REAL_VALUE_TYPE dconstm1;
                    100: 
                    101: /* All references to the following fixed hard registers go through
                    102:    these unique rtl objects.  On machines where the frame-pointer and
                    103:    arg-pointer are the same register, they use the same unique object.
                    104: 
                    105:    After register allocation, other rtl objects which used to be pseudo-regs
                    106:    may be clobbered to refer to the frame-pointer register.
                    107:    But references that were originally to the frame-pointer can be
                    108:    distinguished from the others because they contain frame_pointer_rtx.
                    109: 
                    110:    In an inline procedure, the stack and frame pointer rtxs may not be
                    111:    used for anything else.  */
                    112: rtx stack_pointer_rtx;         /* (REG:Pmode STACK_POINTER_REGNUM) */
                    113: rtx frame_pointer_rtx;         /* (REG:Pmode FRAME_POINTER_REGNUM) */
                    114: rtx arg_pointer_rtx;           /* (REG:Pmode ARG_POINTER_REGNUM) */
                    115: rtx struct_value_rtx;          /* (REG:Pmode STRUCT_VALUE_REGNUM) */
                    116: rtx struct_value_incoming_rtx; /* (REG:Pmode STRUCT_VALUE_INCOMING_REGNUM) */
                    117: rtx static_chain_rtx;          /* (REG:Pmode STATIC_CHAIN_REGNUM) */
                    118: rtx static_chain_incoming_rtx; /* (REG:Pmode STATIC_CHAIN_INCOMING_REGNUM) */
                    119: rtx pic_offset_table_rtx;      /* (REG:Pmode PIC_OFFSET_TABLE_REGNUM) */
                    120: 
                    121: rtx virtual_incoming_args_rtx; /* (REG:Pmode VIRTUAL_INCOMING_ARGS_REGNUM) */
                    122: rtx virtual_stack_vars_rtx;    /* (REG:Pmode VIRTUAL_STACK_VARS_REGNUM) */
                    123: rtx virtual_stack_dynamic_rtx; /* (REG:Pmode VIRTUAL_STACK_DYNAMIC_REGNUM) */
                    124: rtx virtual_outgoing_args_rtx; /* (REG:Pmode VIRTUAL_OUTGOING_ARGS_REGNUM) */
                    125: 
                    126: /* We make one copy of (const_int C) where C is in
                    127:    [- MAX_SAVED_CONST_INT, MAX_SAVED_CONST_INT]
                    128:    to save space during the compilation and simplify comparisons of
                    129:    integers.  */
                    130: 
                    131: #define MAX_SAVED_CONST_INT 64
                    132: 
                    133: static rtx const_int_rtx[MAX_SAVED_CONST_INT * 2 + 1];
                    134: 
                    135: /* The ends of the doubly-linked chain of rtl for the current function.
                    136:    Both are reset to null at the start of rtl generation for the function.
                    137:    
                    138:    start_sequence saves both of these on `sequence_stack' and then
                    139:    starts a new, nested sequence of insns.  */
                    140: 
                    141: static rtx first_insn = NULL;
                    142: static rtx last_insn = NULL;
                    143: 
                    144: /* INSN_UID for next insn emitted.
                    145:    Reset to 1 for each function compiled.  */
                    146: 
                    147: static int cur_insn_uid = 1;
                    148: 
                    149: /* Line number and source file of the last line-number NOTE emitted.
                    150:    This is used to avoid generating duplicates.  */
                    151: 
                    152: static int last_linenum = 0;
                    153: static char *last_filename = 0;
                    154: 
                    155: /* A vector indexed by pseudo reg number.  The allocated length
                    156:    of this vector is regno_pointer_flag_length.  Since this
                    157:    vector is needed during the expansion phase when the total
                    158:    number of registers in the function is not yet known,
                    159:    it is copied and made bigger when necessary.  */
                    160: 
                    161: char *regno_pointer_flag;
                    162: int regno_pointer_flag_length;
                    163: 
                    164: /* Indexed by pseudo register number, gives the rtx for that pseudo.
                    165:    Allocated in parallel with regno_pointer_flag.  */
                    166: 
                    167: rtx *regno_reg_rtx;
                    168: 
                    169: /* Stack of pending (incomplete) sequences saved by `start_sequence'.
                    170:    Each element describes one pending sequence.
                    171:    The main insn-chain is saved in the last element of the chain,
                    172:    unless the chain is empty.  */
                    173: 
                    174: struct sequence_stack *sequence_stack;
                    175: 
                    176: /* start_sequence and gen_sequence can make a lot of rtx expressions which are
                    177:    shortly thrown away.  We use two mechanisms to prevent this waste:
                    178: 
                    179:    First, we keep a list of the expressions used to represent the sequence
                    180:    stack in sequence_element_free_list.
                    181: 
                    182:    Second, for sizes up to 5 elements, we keep a SEQUENCE and its associated
                    183:    rtvec for use by gen_sequence.  One entry for each size is sufficient
                    184:    because most cases are calls to gen_sequence followed by immediately
                    185:    emitting the SEQUENCE.  Reuse is safe since emitting a sequence is
                    186:    destructive on the insn in it anyway and hence can't be redone.
                    187: 
                    188:    We do not bother to save this cached data over nested function calls.
                    189:    Instead, we just reinitialize them.  */
                    190: 
                    191: #define SEQUENCE_RESULT_SIZE 5
                    192: 
                    193: static struct sequence_stack *sequence_element_free_list;
                    194: static rtx sequence_result[SEQUENCE_RESULT_SIZE];
                    195: 
                    196: extern int rtx_equal_function_value_matters;
                    197: 
                    198: /* Filename and line number of last line-number note,
                    199:    whether we actually emitted it or not.  */
                    200: extern char *emit_filename;
                    201: extern int emit_lineno;
                    202: 
                    203: rtx change_address ();
                    204: void init_emit ();
                    205: 
                    206: /* rtx gen_rtx (code, mode, [element1, ..., elementn])
                    207: **
                    208: **         This routine generates an RTX of the size specified by
                    209: **     <code>, which is an RTX code.   The RTX structure is initialized
                    210: **     from the arguments <element1> through <elementn>, which are
                    211: **     interpreted according to the specific RTX type's format.   The
                    212: **     special machine mode associated with the rtx (if any) is specified
                    213: **     in <mode>.
                    214: **
                    215: **         gen_rtx() can be invoked in a way which resembles the lisp-like
                    216: **     rtx it will generate.   For example, the following rtx structure:
                    217: **
                    218: **           (plus:QI (mem:QI (reg:SI 1))
                    219: **                    (mem:QI (plusw:SI (reg:SI 2) (reg:SI 3))))
                    220: **
                    221: **             ...would be generated by the following C code:
                    222: **
                    223: **             gen_rtx (PLUS, QImode,
                    224: **                 gen_rtx (MEM, QImode,
                    225: **                     gen_rtx (REG, SImode, 1)),
                    226: **                 gen_rtx (MEM, QImode,
                    227: **                     gen_rtx (PLUS, SImode,
                    228: **                         gen_rtx (REG, SImode, 2),
                    229: **                         gen_rtx (REG, SImode, 3)))),
                    230: */
                    231: 
                    232: /*VARARGS2*/
                    233: rtx
                    234: gen_rtx (va_alist)
                    235:      va_dcl
                    236: {
                    237:   va_list p;
                    238:   enum rtx_code code;
                    239:   enum machine_mode mode;
                    240:   register int i;              /* Array indices...                     */
                    241:   register char *fmt;          /* Current rtx's format...              */
                    242:   register rtx rt_val;         /* RTX to return to caller...           */
                    243: 
                    244:   va_start (p);
                    245:   code = va_arg (p, enum rtx_code);
                    246:   mode = va_arg (p, enum machine_mode);
                    247: 
                    248:   if (code == CONST_INT)
                    249:     {
                    250:       int arg = va_arg (p, int);
                    251: 
                    252:       if (arg >= - MAX_SAVED_CONST_INT && arg <= MAX_SAVED_CONST_INT)
                    253:        return const_int_rtx[arg + MAX_SAVED_CONST_INT];
                    254: 
                    255:       if (const_true_rtx && arg == STORE_FLAG_VALUE)
                    256:        return const_true_rtx;
                    257: 
                    258:       rt_val = rtx_alloc (code);
                    259:       INTVAL (rt_val) = arg;
                    260:     }
                    261:   else if (code == REG)
                    262:     {
                    263:       int regno = va_arg (p, int);
                    264: 
                    265:       /* In case the MD file explicitly references the frame pointer, have
                    266:         all such references point to the same frame pointer.  This is used
                    267:         during frame pointer elimination to distinguish the explicit
                    268:         references to these registers from psuedos that happened to be
                    269:         assigned to them.
                    270: 
                    271:         If we have eliminated the frame pointer or arg pointer, we will
                    272:         be using it as a normal register, for example as a spill register.
                    273:         In such cases, we might be accessing it in a mode that is not
                    274:         Pmode and therefore cannot use the pre-allocated rtx.  */
                    275: 
                    276:       if (frame_pointer_rtx && regno == FRAME_POINTER_REGNUM && mode == Pmode)
                    277:        return frame_pointer_rtx;
                    278: #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
                    279:       if (arg_pointer_rtx && regno == ARG_POINTER_REGNUM && mode == Pmode)
                    280:        return arg_pointer_rtx;
                    281: #endif
                    282:       if (stack_pointer_rtx && regno == STACK_POINTER_REGNUM && mode == Pmode)
                    283:        return stack_pointer_rtx;
                    284:       else
                    285:        {
                    286:          rt_val = rtx_alloc (code);
                    287:          rt_val->mode = mode;
                    288:          REGNO (rt_val) = regno;
                    289:          return rt_val;
                    290:        }
                    291:     }
                    292:   else
                    293:     {
                    294:       rt_val = rtx_alloc (code);       /* Allocate the storage space.  */
                    295:       rt_val->mode = mode;             /* Store the machine mode...  */
                    296: 
                    297:       fmt = GET_RTX_FORMAT (code);     /* Find the right format...  */
                    298:       for (i = 0; i < GET_RTX_LENGTH (code); i++)
                    299:        {
                    300:          switch (*fmt++)
                    301:            {
                    302:            case '0':           /* Unused field.  */
                    303:              break;
                    304: 
                    305:            case 'i':           /* An integer?  */
                    306:              XINT (rt_val, i) = va_arg (p, int);
                    307:              break;
                    308: 
                    309:            case 's':           /* A string?  */
                    310:              XSTR (rt_val, i) = va_arg (p, char *);
                    311:              break;
                    312: 
                    313:            case 'e':           /* An expression?  */
                    314:            case 'u':           /* An insn?  Same except when printing.  */
                    315:              XEXP (rt_val, i) = va_arg (p, rtx);
                    316:              break;
                    317: 
                    318:            case 'E':           /* An RTX vector?  */
                    319:              XVEC (rt_val, i) = va_arg (p, rtvec);
                    320:              break;
                    321: 
                    322:            default:
                    323:              abort();
                    324:            }
                    325:        }
                    326:     }
                    327:   va_end (p);
                    328:   return rt_val;               /* Return the new RTX...                */
                    329: }
                    330: 
                    331: /* gen_rtvec (n, [rt1, ..., rtn])
                    332: **
                    333: **         This routine creates an rtvec and stores within it the
                    334: **     pointers to rtx's which are its arguments.
                    335: */
                    336: 
                    337: /*VARARGS1*/
                    338: rtvec
                    339: gen_rtvec (va_alist)
                    340:      va_dcl
                    341: {
                    342:   int n, i;
                    343:   va_list p;
                    344:   rtx *vector;
                    345: 
                    346:   va_start (p);
                    347:   n = va_arg (p, int);
                    348: 
                    349:   if (n == 0)
                    350:     return NULL_RTVEC;         /* Don't allocate an empty rtvec...     */
                    351: 
                    352:   vector = (rtx *) alloca (n * sizeof (rtx));
                    353:   for (i = 0; i < n; i++)
                    354:     vector[i] = va_arg (p, rtx);
                    355:   va_end (p);
                    356: 
                    357:   return gen_rtvec_v (n, vector);
                    358: }
                    359: 
                    360: rtvec
                    361: gen_rtvec_v (n, argp)
                    362:      int n;
                    363:      rtx *argp;
                    364: {
                    365:   register int i;
                    366:   register rtvec rt_val;
                    367: 
                    368:   if (n == 0)
                    369:     return NULL_RTVEC;         /* Don't allocate an empty rtvec...     */
                    370: 
                    371:   rt_val = rtvec_alloc (n);    /* Allocate an rtvec...                 */
                    372: 
                    373:   for (i = 0; i < n; i++)
                    374:     rt_val->elem[i].rtx = *argp++;
                    375: 
                    376:   return rt_val;
                    377: }
                    378: 
                    379: /* Generate a REG rtx for a new pseudo register of mode MODE.
                    380:    This pseudo is assigned the next sequential register number.  */
                    381: 
                    382: rtx
                    383: gen_reg_rtx (mode)
                    384:      enum machine_mode mode;
                    385: {
                    386:   register rtx val;
                    387: 
                    388:   /* Don't let anything called by or after reload create new registers
                    389:      (actually, registers can't be created after flow, but this is a good
                    390:      approximation).  */
                    391: 
                    392:   if (reload_in_progress || reload_completed)
                    393:     abort ();
                    394: 
                    395:   /* Make sure regno_pointer_flag and regno_reg_rtx are large
                    396:      enough to have an element for this pseudo reg number.  */
                    397: 
                    398:   if (reg_rtx_no == regno_pointer_flag_length)
                    399:     {
                    400:       rtx *new1;
                    401:       char *new =
                    402:        (char *) oballoc (regno_pointer_flag_length * 2);
                    403:       bzero (new, regno_pointer_flag_length * 2);
                    404:       bcopy (regno_pointer_flag, new, regno_pointer_flag_length);
                    405:       regno_pointer_flag = new;
                    406: 
                    407:       new1 = (rtx *) oballoc (regno_pointer_flag_length * 2 * sizeof (rtx));
                    408:       bzero (new1, regno_pointer_flag_length * 2 * sizeof (rtx));
                    409:       bcopy (regno_reg_rtx, new1, regno_pointer_flag_length * sizeof (rtx));
                    410:       regno_reg_rtx = new1;
                    411: 
                    412:       regno_pointer_flag_length *= 2;
                    413:     }
                    414: 
                    415:   val = gen_rtx (REG, mode, reg_rtx_no);
                    416:   regno_reg_rtx[reg_rtx_no++] = val;
                    417:   return val;
                    418: }
                    419: 
                    420: /* Identify REG as a probable pointer register.  */
                    421: 
                    422: void
                    423: mark_reg_pointer (reg)
                    424:      rtx reg;
                    425: {
                    426:   REGNO_POINTER_FLAG (REGNO (reg)) = 1;
                    427: }
                    428: 
                    429: /* Return 1 plus largest pseudo reg number used in the current function.  */
                    430: 
                    431: int
                    432: max_reg_num ()
                    433: {
                    434:   return reg_rtx_no;
                    435: }
                    436: 
                    437: /* Return 1 + the largest label number used so far in the current function.  */
                    438: 
                    439: int
                    440: max_label_num ()
                    441: {
                    442:   if (last_label_num && label_num == base_label_num)
                    443:     return last_label_num;
                    444:   return label_num;
                    445: }
                    446: 
                    447: /* Return first label number used in this function (if any were used).  */
                    448: 
                    449: int
                    450: get_first_label_num ()
                    451: {
                    452:   return first_label_num;
                    453: }
                    454: 
                    455: /* Return a value representing some low-order bits of X, where the number
                    456:    of low-order bits is given by MODE.  Note that no conversion is done
                    457:    between floating-point and fixed-point values, rather, the bit 
                    458:    representation is returned.
                    459: 
                    460:    This function handles the cases in common between gen_lowpart, below,
                    461:    and two variants in cse.c and combine.c.  These are the cases that can
                    462:    be safely handled at all points in the compilation.
                    463: 
                    464:    If this is not a case we can handle, return 0.  */
                    465: 
                    466: rtx
                    467: gen_lowpart_common (mode, x)
                    468:      enum machine_mode mode;
                    469:      register rtx x;
                    470: {
                    471:   int word = 0;
                    472: 
                    473:   if (GET_MODE (x) == mode)
                    474:     return x;
                    475: 
                    476:   /* MODE must occupy no more words than the mode of X.  */
                    477:   if (GET_MODE (x) != VOIDmode
                    478:       && ((GET_MODE_SIZE (mode) + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD
                    479:          > ((GET_MODE_SIZE (GET_MODE (x)) + (UNITS_PER_WORD - 1))
                    480:             / UNITS_PER_WORD)))
                    481:     return 0;
                    482: 
                    483:   if (WORDS_BIG_ENDIAN && GET_MODE_SIZE (GET_MODE (x)) > UNITS_PER_WORD)
                    484:     word = ((GET_MODE_SIZE (GET_MODE (x))
                    485:             - MAX (GET_MODE_SIZE (mode), UNITS_PER_WORD))
                    486:            / UNITS_PER_WORD);
                    487: 
                    488:   if ((GET_CODE (x) == ZERO_EXTEND || GET_CODE (x) == SIGN_EXTEND)
                    489:       && GET_MODE_CLASS (mode) == MODE_INT)
                    490:     {
                    491:       /* If we are getting the low-order part of something that has been
                    492:         sign- or zero-extended, we can either just use the object being
                    493:         extended or make a narrower extension.  If we want an even smaller
                    494:         piece than the size of the object being extended, call ourselves
                    495:         recursively.
                    496: 
                    497:         This case is used mostly by combine and cse.  */
                    498: 
                    499:       if (GET_MODE (XEXP (x, 0)) == mode)
                    500:        return XEXP (x, 0);
                    501:       else if (GET_MODE_SIZE (mode) < GET_MODE_SIZE (GET_MODE (XEXP (x, 0))))
                    502:        return gen_lowpart_common (mode, XEXP (x, 0));
                    503:       else if (GET_MODE_SIZE (mode) < GET_MODE_SIZE (GET_MODE (x)))
                    504:        return gen_rtx (GET_CODE (x), mode, XEXP (x, 0));
                    505:     }
                    506:   else if (GET_CODE (x) == SUBREG
                    507:           && (GET_MODE_SIZE (mode) <= UNITS_PER_WORD
                    508:               || GET_MODE_SIZE (mode) == GET_MODE_UNIT_SIZE (GET_MODE (x))))
                    509:     return (GET_MODE (SUBREG_REG (x)) == mode && SUBREG_WORD (x) == 0
                    510:            ? SUBREG_REG (x)
                    511:            : gen_rtx (SUBREG, mode, SUBREG_REG (x), SUBREG_WORD (x)));
                    512:   else if (GET_CODE (x) == REG)
                    513:     {
                    514:       /* If the register is not valid for MODE, return 0.  If we don't
                    515:         do this, there is no way to fix up the resulting REG later.  */
                    516:       if (REGNO (x) < FIRST_PSEUDO_REGISTER
                    517:          && ! HARD_REGNO_MODE_OK (REGNO (x) + word, mode))
                    518:        return 0;
                    519:       else if (REGNO (x) < FIRST_PSEUDO_REGISTER
                    520:               /* integrate.c can't handle parts of a return value register. */
                    521:               && (! REG_FUNCTION_VALUE_P (x)
                    522:                   || ! rtx_equal_function_value_matters))
                    523:        return gen_rtx (REG, mode, REGNO (x) + word);
                    524:       else
                    525:        return gen_rtx (SUBREG, mode, x, word);
                    526:     }
                    527: 
                    528:   /* If X is a CONST_INT or a CONST_DOUBLE, extract the appropriate bits
                    529:      from the low-order part of the constant.  */
                    530:   else if (GET_MODE_CLASS (mode) == MODE_INT && GET_MODE (x) == VOIDmode
                    531:           && (GET_CODE (x) == CONST_INT || GET_CODE (x) == CONST_DOUBLE))
                    532:     return (GET_MODE_BITSIZE (mode) > HOST_BITS_PER_INT ? x
                    533:            : (GET_MODE_BITSIZE (mode) == HOST_BITS_PER_INT
                    534:               && GET_CODE (x) == CONST_INT) ? x
                    535:            : gen_rtx (CONST_INT, VOIDmode,
                    536:                       (GET_MODE_MASK (mode)
                    537:                        & (GET_CODE (x) == CONST_INT
                    538:                           ? INTVAL (x) : CONST_DOUBLE_LOW (x)))));
                    539: 
                    540:   /* Otherwise, we can't do this.  */
                    541:   return 0;
                    542: }
                    543: 
                    544: /* Assuming that X is an rtx (e.g., MEM, REG or SUBREG) for a value,
                    545:    return an rtx (MEM, SUBREG, or CONST_INT) that refers to the
                    546:    least-significant part of X.
                    547:    MODE specifies how big a part of X to return;
                    548:    it usually should not be larger than a word.
                    549:    If X is a MEM whose address is a QUEUED, the value may be so also.  */
                    550: 
                    551: rtx
                    552: gen_lowpart (mode, x)
                    553:      enum machine_mode mode;
                    554:      register rtx x;
                    555: {
                    556:   rtx result = gen_lowpart_common (mode, x);
                    557: 
                    558:   if (result)
                    559:     return result;
                    560:   else if (GET_CODE (x) == MEM)
                    561:     {
                    562:       /* The only additional case we can do is MEM.  */
                    563:       register int offset = 0;
                    564:       if (WORDS_BIG_ENDIAN)
                    565:        offset = (MAX (GET_MODE_SIZE (GET_MODE (x)), UNITS_PER_WORD)
                    566:                  - MAX (GET_MODE_SIZE (mode), UNITS_PER_WORD));
                    567: 
                    568:       if (BYTES_BIG_ENDIAN)
                    569:        /* Adjust the address so that the address-after-the-data
                    570:           is unchanged.  */
                    571:        offset -= (MIN (UNITS_PER_WORD, GET_MODE_SIZE (mode))
                    572:                   - MIN (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (x))));
                    573: 
                    574:       return change_address (x, mode, plus_constant (XEXP (x, 0), offset));
                    575:     }
                    576:   else
                    577:     abort ();
                    578: }
                    579: 
                    580: /* Return 1 iff X, assumed to be a SUBREG,
                    581:    refers to the least significant part of its containing reg.
                    582:    If X is not a SUBREG, always return 1 (it is its own low part!).  */
                    583: 
                    584: int
                    585: subreg_lowpart_p (x)
                    586:      rtx x;
                    587: {
                    588:   if (GET_CODE (x) != SUBREG)
                    589:     return 1;
                    590: 
                    591:   if (WORDS_BIG_ENDIAN
                    592:       && GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))) > UNITS_PER_WORD)
                    593:     return (SUBREG_WORD (x)
                    594:            == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (x)))
                    595:                 - MAX (GET_MODE_SIZE (GET_MODE (x)), UNITS_PER_WORD))
                    596:                / UNITS_PER_WORD));
                    597: 
                    598:   return SUBREG_WORD (x) == 0;
                    599: }
                    600: 
                    601: /* Return subword I of operand OP.
                    602:    The word number, I, is interpreted as the word number starting at the
                    603:    low-order address.  Word 0 is the low-order word if not WORDS_BIG_ENDIAN,
                    604:    otherwise it is the high-order word.
                    605: 
                    606:    If we cannot extract the required word, we return zero.  Otherwise, an
                    607:    rtx corresponding to the requested word will be returned.
                    608: 
                    609:    VALIDATE_ADDRESS is nonzero if the address should be validated.  Before
                    610:    reload has completed, a valid address will always be returned.  After
                    611:    reload, if a valid address cannot be returned, we return zero.
                    612: 
                    613:    If VALIDATE_ADDRESS is zero, we simply form the required address; validating
                    614:    it is the responsibility of the caller.
                    615: 
                    616:    MODE is the mode of OP in case it is a CONST_INT.  */
                    617: 
                    618: rtx
                    619: operand_subword (op, i, validate_address, mode)
                    620:      rtx op;
                    621:      int i;
                    622:      int validate_address;
                    623:      enum machine_mode mode;
                    624: {
                    625:   int val;
                    626:   int size_ratio = HOST_BITS_PER_INT / BITS_PER_WORD;
                    627: 
                    628:   if (mode == VOIDmode)
                    629:     mode = GET_MODE (op);
                    630: 
                    631:   if (mode == VOIDmode)
                    632:     abort ();
                    633: 
                    634:   /* If OP is narrower than a word or if we want a word outside OP, fail.  */
                    635:   if (mode != BLKmode
                    636:       && (GET_MODE_SIZE (mode) < UNITS_PER_WORD
                    637:          || (i + 1) * UNITS_PER_WORD > GET_MODE_SIZE (mode)))
                    638:     return 0;
                    639: 
                    640:   /* If OP is already an integer word, return it.  */
                    641:   if (GET_MODE_CLASS (mode) == MODE_INT
                    642:       && GET_MODE_SIZE (mode) == UNITS_PER_WORD)
                    643:     return op;
                    644: 
                    645:   /* If OP is a REG or SUBREG, we can handle it very simply.  */
                    646:   if (GET_CODE (op) == REG)
                    647:     {
                    648:       /* If the register is not valid for MODE, return 0.  If we don't
                    649:         do this, there is no way to fix up the resulting REG later.  */
                    650:       if (REGNO (op) < FIRST_PSEUDO_REGISTER
                    651:          && ! HARD_REGNO_MODE_OK (REGNO (op) + i, word_mode))
                    652:        return 0;
                    653:       else if (REGNO (op) >= FIRST_PSEUDO_REGISTER
                    654:               || (REG_FUNCTION_VALUE_P (op)
                    655:                   && rtx_equal_function_value_matters))
                    656:        return gen_rtx (SUBREG, word_mode, op, i);
                    657:       else
                    658:        return gen_rtx (REG, word_mode, REGNO (op) + i);
                    659:     }
                    660:   else if (GET_CODE (op) == SUBREG)
                    661:     return gen_rtx (SUBREG, word_mode, SUBREG_REG (op), i + SUBREG_WORD (op));
                    662: 
                    663:   /* Form a new MEM at the requested address.  */
                    664:   if (GET_CODE (op) == MEM)
                    665:     {
                    666:       rtx addr = plus_constant (XEXP (op, 0), i * UNITS_PER_WORD);
                    667:       rtx new;
                    668: 
                    669:       if (validate_address)
                    670:        {
                    671:          if (reload_completed)
                    672:            {
                    673:              if (! strict_memory_address_p (word_mode, addr))
                    674:                return 0;
                    675:            }
                    676:          else
                    677:            addr = memory_address (word_mode, addr);
                    678:        }
                    679: 
                    680:       new = gen_rtx (MEM, word_mode, addr);
                    681: 
                    682:       MEM_VOLATILE_P (new) = MEM_VOLATILE_P (op);
                    683:       MEM_IN_STRUCT_P (new) = MEM_IN_STRUCT_P (op);
                    684:       RTX_UNCHANGING_P (new) = RTX_UNCHANGING_P (op);
                    685: 
                    686:       return new;
                    687:     }
                    688: 
                    689:   /* The only remaining cases are when OP is a constant.  If the host and
                    690:      target floating formats are the same, handling two-word floating
                    691:      constants are easy.  */
                    692:   if (((HOST_FLOAT_FORMAT == TARGET_FLOAT_FORMAT
                    693:        && HOST_BITS_PER_INT == BITS_PER_WORD)
                    694:        || flag_pretend_float)
                    695:       && GET_MODE_CLASS (mode) == MODE_FLOAT
                    696:       && GET_MODE_SIZE (mode) == 2 * UNITS_PER_WORD
                    697:       && GET_CODE (op) == CONST_DOUBLE)
                    698:     return gen_rtx (CONST_INT, VOIDmode,
                    699:                    i ? CONST_DOUBLE_HIGH (op) : CONST_DOUBLE_LOW (op));
                    700: 
                    701:   /* Single word float is a little harder, since single- and double-word
                    702:      values often do not have the same high-order bits.  We have already
                    703:      verified that we want the only defined word of the single-word value.  */
                    704:   if (((HOST_FLOAT_FORMAT == TARGET_FLOAT_FORMAT
                    705:        && HOST_BITS_PER_INT == BITS_PER_WORD)
                    706:        || flag_pretend_float)
                    707:       && GET_MODE_CLASS (mode) == MODE_FLOAT
                    708:       && GET_MODE_SIZE (mode) == UNITS_PER_WORD
                    709:       && GET_CODE (op) == CONST_DOUBLE)
                    710:     {
                    711:       double d;
                    712:       union {float f; int i; } u;
                    713: 
                    714:       REAL_VALUE_FROM_CONST_DOUBLE (d, op);
                    715: 
                    716:       u.f = d;
                    717:       return gen_rtx (CONST_INT, VOIDmode, u.i);
                    718:     }
                    719:       
                    720:   /* The only remaining cases that we can handle are integers.
                    721:      Convert to proper endianness now since these cases need it.
                    722:      At this point, i == 0 means the low-order word.  
                    723: 
                    724:      Note that it must be that BITS_PER_WORD <= HOST_BITS_PER_INT.
                    725:      This is because if it were greater, it could only have been two
                    726:      times greater since we do not support making wider constants.  In
                    727:      that case, it MODE would have already been the proper size and
                    728:      it would have been handled above.  This means we do not have to
                    729:      worry about the case where we would be returning a CONST_DOUBLE.  */
                    730: 
                    731:   if (GET_MODE_CLASS (mode) != MODE_INT
                    732:       || (GET_CODE (op) != CONST_INT && GET_CODE (op) != CONST_DOUBLE))
                    733:     return 0;
                    734: 
                    735:   if (WORDS_BIG_ENDIAN)
                    736:     i = GET_MODE_SIZE (mode) / UNITS_PER_WORD - 1 - i;
                    737: 
                    738:   /* Find out which word on the host machine this value is in and get
                    739:      it from the constant.  */
                    740:   val = (i / size_ratio == 0
                    741:         ? (GET_CODE (op) == CONST_INT ? INTVAL (op) : CONST_DOUBLE_LOW (op))
                    742:         : (GET_CODE (op) == CONST_INT
                    743:            ? (INTVAL (op) < 0 ? ~0 : 0) : CONST_DOUBLE_HIGH (op)));
                    744: 
                    745:   /* If BITS_PER_WORD is smaller than an int, get the appropriate bits.  */
                    746:   if (BITS_PER_WORD < HOST_BITS_PER_INT)
                    747:     val = ((val >> ((i % size_ratio) * BITS_PER_WORD))
                    748:           & ((1 << (BITS_PER_WORD % HOST_BITS_PER_INT)) - 1));
                    749: 
                    750:   return gen_rtx (CONST_INT, VOIDmode, val);
                    751: }
                    752: 
                    753: /* Similar to `operand_subword', but never return 0.  If we can't extract
                    754:    the required subword, put OP into a register and try again.  If that fails,
                    755:    abort.  We always validate the address in this case.  It is not valid
                    756:    to call this function after reload; it is mostly meant for RTL
                    757:    generation. 
                    758: 
                    759:    MODE is the mode of OP, in case it is CONST_INT.  */
                    760: 
                    761: rtx
                    762: operand_subword_force (op, i, mode)
                    763:      rtx op;
                    764:      int i;
                    765:      enum machine_mode mode;
                    766: {
                    767:   rtx result = operand_subword (op, i, 1, mode);
                    768: 
                    769:   if (result)
                    770:     return result;
                    771: 
                    772:   if (mode != BLKmode && mode != VOIDmode)
                    773:     op = force_reg (mode, op);
                    774: 
                    775:   result = operand_subword (op, i, 1, mode);
                    776:   if (result == 0)
                    777:     abort ();
                    778: 
                    779:   return result;
                    780: }
                    781: 
                    782: /* Given a compare instruction, swap the operands.
                    783:    A test instruction is changed into a compare of 0 against the operand.  */
                    784: 
                    785: void
                    786: reverse_comparison (insn)
                    787:      rtx insn;
                    788: {
                    789:   rtx body = PATTERN (insn);
                    790:   rtx comp;
                    791: 
                    792:   if (GET_CODE (body) == SET)
                    793:     comp = SET_SRC (body);
                    794:   else
                    795:     comp = SET_SRC (XVECEXP (body, 0, 0));
                    796: 
                    797:   if (GET_CODE (comp) == COMPARE)
                    798:     {
                    799:       rtx op0 = XEXP (comp, 0);
                    800:       rtx op1 = XEXP (comp, 1);
                    801:       XEXP (comp, 0) = op1;
                    802:       XEXP (comp, 1) = op0;
                    803:     }
                    804:   else
                    805:     {
                    806:       rtx new = gen_rtx (COMPARE, VOIDmode,
                    807:                         CONST0_RTX (GET_MODE (comp)), comp);
                    808:       if (GET_CODE (body) == SET)
                    809:        SET_SRC (body) = new;
                    810:       else
                    811:        SET_SRC (XVECEXP (body, 0, 0)) = new;
                    812:     }
                    813: }
                    814: 
                    815: /* Return a memory reference like MEMREF, but with its mode changed
                    816:    to MODE and its address changed to ADDR.
                    817:    (VOIDmode means don't change the mode.
                    818:    NULL for ADDR means don't change the address.)  */
                    819: 
                    820: rtx
                    821: change_address (memref, mode, addr)
                    822:      rtx memref;
                    823:      enum machine_mode mode;
                    824:      rtx addr;
                    825: {
                    826:   rtx new;
                    827: 
                    828:   if (GET_CODE (memref) != MEM)
                    829:     abort ();
                    830:   if (mode == VOIDmode)
                    831:     mode = GET_MODE (memref);
                    832:   if (addr == 0)
                    833:     addr = XEXP (memref, 0);
                    834: 
                    835:   /* If reload is in progress or has completed, ADDR must be valid.
                    836:      Otherwise, we can call memory_address to make it valid.  */
                    837:   if (reload_completed || reload_in_progress)
                    838:     {
                    839:       if (! memory_address_p (mode, addr))
                    840:        abort ();
                    841:     }
                    842:   else
                    843:     addr = memory_address (mode, addr);
                    844:        
                    845:   new = gen_rtx (MEM, mode, addr);
                    846:   MEM_VOLATILE_P (new) = MEM_VOLATILE_P (memref);
                    847:   RTX_UNCHANGING_P (new) = RTX_UNCHANGING_P (memref);
                    848:   MEM_IN_STRUCT_P (new) = MEM_IN_STRUCT_P (memref);
                    849:   return new;
                    850: }
                    851: 
                    852: /* Return a newly created CODE_LABEL rtx with a unique label number.  */
                    853: 
                    854: rtx
                    855: gen_label_rtx ()
                    856: {
                    857:   register rtx label = gen_rtx (CODE_LABEL, VOIDmode, 0, 0, 0, label_num++, 0);
                    858:   LABEL_NUSES (label) = 0;
                    859:   return label;
                    860: }
                    861: 
                    862: /* For procedure integration.  */
                    863: 
                    864: /* Return a newly created INLINE_HEADER rtx.  Should allocate this
                    865:    from a permanent obstack when the opportunity arises.  */
                    866: 
                    867: rtx
                    868: gen_inline_header_rtx (first_insn, first_parm_insn, first_labelno,
                    869:                       last_labelno, max_parm_regnum, max_regnum, args_size,
                    870:                       pops_args, stack_slots, function_flags,
                    871:                       outgoing_args_size, original_arg_vector,
                    872:                       original_decl_initial)
                    873:      rtx first_insn, first_parm_insn;
                    874:      int first_labelno, last_labelno, max_parm_regnum, max_regnum, args_size;
                    875:      int pops_args;
                    876:      rtx stack_slots;
                    877:      int function_flags;
                    878:      int outgoing_args_size;
                    879:      rtvec original_arg_vector;
                    880:      rtx original_decl_initial;
                    881: {
                    882:   rtx header = gen_rtx (INLINE_HEADER, VOIDmode,
                    883:                        cur_insn_uid++, NULL,
                    884:                        first_insn, first_parm_insn,
                    885:                        first_labelno, last_labelno,
                    886:                        max_parm_regnum, max_regnum, args_size, pops_args,
                    887:                        stack_slots, function_flags, outgoing_args_size,
                    888:                        original_arg_vector, original_decl_initial);
                    889:   return header;
                    890: }
                    891: 
                    892: /* Install new pointers to the first and last insns in the chain.
                    893:    Used for an inline-procedure after copying the insn chain.  */
                    894: 
                    895: void
                    896: set_new_first_and_last_insn (first, last)
                    897:      rtx first, last;
                    898: {
                    899:   first_insn = first;
                    900:   last_insn = last;
                    901: }
                    902: 
                    903: /* Set the range of label numbers found in the current function.
                    904:    This is used when belatedly compiling an inline function.  */
                    905: 
                    906: void
                    907: set_new_first_and_last_label_num (first, last)
                    908:      int first, last;
                    909: {
                    910:   base_label_num = label_num;
                    911:   first_label_num = first;
                    912:   last_label_num = last;
                    913: }
                    914: 
                    915: /* Save all variables describing the current status into the structure *P.
                    916:    This is used before starting a nested function.  */
                    917: 
                    918: void
                    919: save_emit_status (p)
                    920:      struct function *p;
                    921: {
                    922:   p->reg_rtx_no = reg_rtx_no;
                    923:   p->first_label_num = first_label_num;
                    924:   p->first_insn = first_insn;
                    925:   p->last_insn = last_insn;
                    926:   p->sequence_stack = sequence_stack;
                    927:   p->cur_insn_uid = cur_insn_uid;
                    928:   p->last_linenum = last_linenum;
                    929:   p->last_filename = last_filename;
                    930:   p->regno_pointer_flag = regno_pointer_flag;
                    931:   p->regno_pointer_flag_length = regno_pointer_flag_length;
                    932:   p->regno_reg_rtx = regno_reg_rtx;
                    933: }
                    934: 
                    935: /* Restore all variables describing the current status from the structure *P.
                    936:    This is used after a nested function.  */
                    937: 
                    938: void
                    939: restore_emit_status (p)
                    940:      struct function *p;
                    941: {
                    942:   int i;
                    943: 
                    944:   reg_rtx_no = p->reg_rtx_no;
                    945:   first_label_num = p->first_label_num;
                    946:   first_insn = p->first_insn;
                    947:   last_insn = p->last_insn;
                    948:   sequence_stack = p->sequence_stack;
                    949:   cur_insn_uid = p->cur_insn_uid;
                    950:   last_linenum = p->last_linenum;
                    951:   last_filename = p->last_filename;
                    952:   regno_pointer_flag = p->regno_pointer_flag;
                    953:   regno_pointer_flag_length = p->regno_pointer_flag_length;
                    954:   regno_reg_rtx = p->regno_reg_rtx;
                    955: 
                    956:   /* Clear our cache of rtx expressions for start_sequence and gen_sequence. */
                    957:   sequence_element_free_list = 0;
                    958:   for (i = 0; i < SEQUENCE_RESULT_SIZE; i++)
                    959:     sequence_result[i] = 0;
                    960: }
                    961: 
                    962: /* Go through all the RTL insn bodies and copy any invalid shared structure.
                    963:    It does not work to do this twice, because the mark bits set here
                    964:    are not cleared afterwards.  */
                    965: 
                    966: void
                    967: unshare_all_rtl (insn)
                    968:      register rtx insn;
                    969: {
                    970:   for (; insn; insn = NEXT_INSN (insn))
                    971:     if (GET_CODE (insn) == INSN || GET_CODE (insn) == JUMP_INSN
                    972:        || GET_CODE (insn) == CALL_INSN)
                    973:       {
                    974:        PATTERN (insn) = copy_rtx_if_shared (PATTERN (insn));
                    975:        REG_NOTES (insn) = copy_rtx_if_shared (REG_NOTES (insn));
                    976:        LOG_LINKS (insn) = copy_rtx_if_shared (LOG_LINKS (insn));
                    977:       }
                    978: 
                    979:   /* Make sure the addresses of stack slots found outside the insn chain
                    980:      (such as, in DECL_RTL of a variable) are not shared
                    981:      with the insn chain.
                    982: 
                    983:      This special care is necessary when the stack slot MEM does not
                    984:      actually appear in the insn chain.  If it does appear, its address
                    985:      is unshared from all else at that point.  */
                    986: 
                    987:   copy_rtx_if_shared (stack_slot_list);
                    988: }
                    989: 
                    990: /* Mark ORIG as in use, and return a copy of it if it was already in use.
                    991:    Recursively does the same for subexpressions.  */
                    992: 
                    993: rtx
                    994: copy_rtx_if_shared (orig)
                    995:      rtx orig;
                    996: {
                    997:   register rtx x = orig;
                    998:   register int i;
                    999:   register enum rtx_code code;
                   1000:   register char *format_ptr;
                   1001:   int copied = 0;
                   1002: 
                   1003:   if (x == 0)
                   1004:     return 0;
                   1005: 
                   1006:   code = GET_CODE (x);
                   1007: 
                   1008:   /* These types may be freely shared.  */
                   1009: 
                   1010:   switch (code)
                   1011:     {
                   1012:     case REG:
                   1013:     case QUEUED:
                   1014:     case CONST_INT:
                   1015:     case CONST_DOUBLE:
                   1016:     case SYMBOL_REF:
                   1017:     case CODE_LABEL:
                   1018:     case PC:
                   1019:     case CC0:
                   1020:     case SCRATCH:
                   1021:       /* SCRATCH must be shared because they represent distinct values. */
                   1022:       return x;
                   1023: 
                   1024:     case INSN:
                   1025:     case JUMP_INSN:
                   1026:     case CALL_INSN:
                   1027:     case NOTE:
                   1028:     case LABEL_REF:
                   1029:     case BARRIER:
                   1030:       /* The chain of insns is not being copied.  */
                   1031:       return x;
                   1032: 
                   1033:     case MEM:
                   1034:       /* A MEM is allowed to be shared if its address is constant
                   1035:         or is a constant plus one of the special registers.  */
                   1036:       if (CONSTANT_ADDRESS_P (XEXP (x, 0))
                   1037:          || XEXP (x, 0) == virtual_stack_vars_rtx
                   1038:          || XEXP (x, 0) == virtual_incoming_args_rtx)
                   1039:        return x;
                   1040: 
                   1041:       if (GET_CODE (XEXP (x, 0)) == PLUS
                   1042:          && (XEXP (XEXP (x, 0), 0) == virtual_stack_vars_rtx
                   1043:              || XEXP (XEXP (x, 0), 0) == virtual_incoming_args_rtx)
                   1044:          && CONSTANT_ADDRESS_P (XEXP (XEXP (x, 0), 1)))
                   1045:        {
                   1046:          /* This MEM can appear in more than one place,
                   1047:             but its address better not be shared with anything else.  */
                   1048:          if (! x->used)
                   1049:            XEXP (x, 0) = copy_rtx_if_shared (XEXP (x, 0));
                   1050:          x->used = 1;
                   1051:          return x;
                   1052:        }
                   1053:     }
                   1054: 
                   1055:   /* This rtx may not be shared.  If it has already been seen,
                   1056:      replace it with a copy of itself.  */
                   1057: 
                   1058:   if (x->used)
                   1059:     {
                   1060:       register rtx copy;
                   1061: 
                   1062:       copy = rtx_alloc (code);
                   1063:       bcopy (x, copy, (sizeof (*copy) - sizeof (copy->fld)
                   1064:                       + sizeof (copy->fld[0]) * GET_RTX_LENGTH (code)));
                   1065:       x = copy;
                   1066:       copied = 1;
                   1067:     }
                   1068:   x->used = 1;
                   1069: 
                   1070:   /* Now scan the subexpressions recursively.
                   1071:      We can store any replaced subexpressions directly into X
                   1072:      since we know X is not shared!  Any vectors in X
                   1073:      must be copied if X was copied.  */
                   1074: 
                   1075:   format_ptr = GET_RTX_FORMAT (code);
                   1076: 
                   1077:   for (i = 0; i < GET_RTX_LENGTH (code); i++)
                   1078:     {
                   1079:       switch (*format_ptr++)
                   1080:        {
                   1081:        case 'e':
                   1082:          XEXP (x, i) = copy_rtx_if_shared (XEXP (x, i));
                   1083:          break;
                   1084: 
                   1085:        case 'E':
                   1086:          if (XVEC (x, i) != NULL)
                   1087:            {
                   1088:              register int j;
                   1089: 
                   1090:              if (copied)
                   1091:                XVEC (x, i) = gen_rtvec_v (XVECLEN (x, i), &XVECEXP (x, i, 0));
                   1092:              for (j = 0; j < XVECLEN (x, i); j++)
                   1093:                XVECEXP (x, i, j)
                   1094:                  = copy_rtx_if_shared (XVECEXP (x, i, j));
                   1095:            }
                   1096:          break;
                   1097:        }
                   1098:     }
                   1099:   return x;
                   1100: }
                   1101: 
                   1102: /* Clear all the USED bits in X to allow copy_rtx_if_shared to be used
                   1103:    to look for shared sub-parts.  */
                   1104: 
                   1105: void
                   1106: reset_used_flags (x)
                   1107:      rtx x;
                   1108: {
                   1109:   register int i, j;
                   1110:   register enum rtx_code code;
                   1111:   register char *format_ptr;
                   1112:   int copied = 0;
                   1113: 
                   1114:   if (x == 0)
                   1115:     return;
                   1116: 
                   1117:   code = GET_CODE (x);
                   1118: 
                   1119:   /* These types may be freely shared so we needn't do any reseting
                   1120:      for them.  */
                   1121: 
                   1122:   switch (code)
                   1123:     {
                   1124:     case REG:
                   1125:     case QUEUED:
                   1126:     case CONST_INT:
                   1127:     case CONST_DOUBLE:
                   1128:     case SYMBOL_REF:
                   1129:     case CODE_LABEL:
                   1130:     case PC:
                   1131:     case CC0:
                   1132:       return;
                   1133: 
                   1134:     case INSN:
                   1135:     case JUMP_INSN:
                   1136:     case CALL_INSN:
                   1137:     case NOTE:
                   1138:     case LABEL_REF:
                   1139:     case BARRIER:
                   1140:       /* The chain of insns is not being copied.  */
                   1141:       return;
                   1142:     }
                   1143: 
                   1144:   x->used = 0;
                   1145: 
                   1146:   format_ptr = GET_RTX_FORMAT (code);
                   1147:   for (i = 0; i < GET_RTX_LENGTH (code); i++)
                   1148:     {
                   1149:       switch (*format_ptr++)
                   1150:        {
                   1151:        case 'e':
                   1152:          reset_used_flags (XEXP (x, i));
                   1153:          break;
                   1154: 
                   1155:        case 'E':
                   1156:          for (j = 0; j < XVECLEN (x, i); j++)
                   1157:            reset_used_flags (XVECEXP (x, i, j));
                   1158:          break;
                   1159:        }
                   1160:     }
                   1161: }
                   1162: 
                   1163: /* Copy X if necessary so that it won't be altered by changes in OTHER.
                   1164:    Return X or the rtx for the pseudo reg the value of X was copied into.
                   1165:    OTHER must be valid as a SET_DEST.  */
                   1166: 
                   1167: rtx
                   1168: make_safe_from (x, other)
                   1169:      rtx x, other;
                   1170: {
                   1171:   while (1)
                   1172:     switch (GET_CODE (other))
                   1173:       {
                   1174:       case SUBREG:
                   1175:        other = SUBREG_REG (other);
                   1176:        break;
                   1177:       case STRICT_LOW_PART:
                   1178:       case SIGN_EXTEND:
                   1179:       case ZERO_EXTEND:
                   1180:        other = XEXP (other, 0);
                   1181:        break;
                   1182:       default:
                   1183:        goto done;
                   1184:       }
                   1185:  done:
                   1186:   if ((GET_CODE (other) == MEM
                   1187:        && ! CONSTANT_P (x)
                   1188:        && GET_CODE (x) != REG
                   1189:        && GET_CODE (x) != SUBREG)
                   1190:       || (GET_CODE (other) == REG
                   1191:          && (REGNO (other) < FIRST_PSEUDO_REGISTER
                   1192:              || reg_mentioned_p (other, x))))
                   1193:     {
                   1194:       rtx temp = gen_reg_rtx (GET_MODE (x));
                   1195:       emit_move_insn (temp, x);
                   1196:       return temp;
                   1197:     }
                   1198:   return x;
                   1199: }
                   1200: 
                   1201: /* Emission of insns (adding them to the doubly-linked list).  */
                   1202: 
                   1203: /* Return the first insn of the current sequence or current function.  */
                   1204: 
                   1205: rtx
                   1206: get_insns ()
                   1207: {
                   1208:   return first_insn;
                   1209: }
                   1210: 
                   1211: /* Return the last insn emitted in current sequence or current function.  */
                   1212: 
                   1213: rtx
                   1214: get_last_insn ()
                   1215: {
                   1216:   return last_insn;
                   1217: }
                   1218: 
                   1219: /* Specify a new insn as the last in the chain.  */
                   1220: 
                   1221: void
                   1222: set_last_insn (insn)
                   1223:      rtx insn;
                   1224: {
                   1225:   if (NEXT_INSN (insn) != 0)
                   1226:     abort ();
                   1227:   last_insn = insn;
                   1228: }
                   1229: 
                   1230: /* Return the last insn emitted, even if it is in a sequence now pushed.  */
                   1231: 
                   1232: rtx
                   1233: get_last_insn_anywhere ()
                   1234: {
                   1235:   struct sequence_stack *stack;
                   1236:   if (last_insn)
                   1237:     return last_insn;
                   1238:   for (stack = sequence_stack; stack; stack = stack->next)
                   1239:     if (stack->last != 0)
                   1240:       return stack->last;
                   1241:   return 0;
                   1242: }
                   1243: 
                   1244: /* Return a number larger than any instruction's uid in this function.  */
                   1245: 
                   1246: int
                   1247: get_max_uid ()
                   1248: {
                   1249:   return cur_insn_uid;
                   1250: }
                   1251: 
                   1252: /* Return the next insn.  If it is a SEQUENCE, return the first insn
                   1253:    of the sequence.  */
                   1254: 
                   1255: rtx
                   1256: next_insn (insn)
                   1257:      rtx insn;
                   1258: {
                   1259:   if (insn)
                   1260:     {
                   1261:       insn = NEXT_INSN (insn);
                   1262:       if (insn && GET_CODE (insn) == INSN
                   1263:          && GET_CODE (PATTERN (insn)) == SEQUENCE)
                   1264:        insn = XVECEXP (PATTERN (insn), 0, 0);
                   1265:     }
                   1266: 
                   1267:   return insn;
                   1268: }
                   1269: 
                   1270: /* Return the previous insn.  If it is a SEQUENCE, return the last insn
                   1271:    of the sequence.  */
                   1272: 
                   1273: rtx
                   1274: previous_insn (insn)
                   1275:      rtx insn;
                   1276: {
                   1277:   if (insn)
                   1278:     {
                   1279:       insn = PREV_INSN (insn);
                   1280:       if (insn && GET_CODE (insn) == INSN
                   1281:          && GET_CODE (PATTERN (insn)) == SEQUENCE)
                   1282:        insn = XVECEXP (PATTERN (insn), 0, XVECLEN (PATTERN (insn), 0) - 1);
                   1283:     }
                   1284: 
                   1285:   return insn;
                   1286: }
                   1287: 
                   1288: /* Return the next insn after INSN that is not a NOTE.  This routine does not
                   1289:    look inside SEQUENCEs.  */
                   1290: 
                   1291: rtx
                   1292: next_nonnote_insn (insn)
                   1293:      rtx insn;
                   1294: {
                   1295:   while (insn)
                   1296:     {
                   1297:       insn = NEXT_INSN (insn);
                   1298:       if (insn == 0 || GET_CODE (insn) != NOTE)
                   1299:        break;
                   1300:     }
                   1301: 
                   1302:   return insn;
                   1303: }
                   1304: 
                   1305: /* Return the previous insn before INSN that is not a NOTE.  This routine does
                   1306:    not look inside SEQUENCEs.  */
                   1307: 
                   1308: rtx
                   1309: prev_nonnote_insn (insn)
                   1310:      rtx insn;
                   1311: {
                   1312:   while (insn)
                   1313:     {
                   1314:       insn = PREV_INSN (insn);
                   1315:       if (insn == 0 || GET_CODE (insn) != NOTE)
                   1316:        break;
                   1317:     }
                   1318: 
                   1319:   return insn;
                   1320: }
                   1321: 
                   1322: /* Return the next INSN, CALL_INSN or JUMP_INSN after INSN;
                   1323:    or 0, if there is none.  This routine does not look inside
                   1324:    SEQUENCEs. */
                   1325: 
                   1326: rtx
                   1327: next_real_insn (insn)
                   1328:      rtx insn;
                   1329: {
                   1330:   while (insn)
                   1331:     {
                   1332:       insn = NEXT_INSN (insn);
                   1333:       if (insn == 0 || GET_CODE (insn) == INSN
                   1334:          || GET_CODE (insn) == CALL_INSN || GET_CODE (insn) == JUMP_INSN)
                   1335:        break;
                   1336:     }
                   1337: 
                   1338:   return insn;
                   1339: }
                   1340: 
                   1341: /* Return the last INSN, CALL_INSN or JUMP_INSN before INSN;
                   1342:    or 0, if there is none.  This routine does not look inside
                   1343:    SEQUENCEs.  */
                   1344: 
                   1345: rtx
                   1346: prev_real_insn (insn)
                   1347:      rtx insn;
                   1348: {
                   1349:   while (insn)
                   1350:     {
                   1351:       insn = PREV_INSN (insn);
                   1352:       if (insn == 0 || GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN
                   1353:          || GET_CODE (insn) == JUMP_INSN)
                   1354:        break;
                   1355:     }
                   1356: 
                   1357:   return insn;
                   1358: }
                   1359: 
                   1360: /* Find the next insn after INSN that really does something.  This routine
                   1361:    does not look inside SEQUENCEs.  Until reload has completed, this is the
                   1362:    same as next_real_insn.  */
                   1363: 
                   1364: rtx
                   1365: next_active_insn (insn)
                   1366:      rtx insn;
                   1367: {
                   1368:   while (insn)
                   1369:     {
                   1370:       insn = NEXT_INSN (insn);
                   1371:       if (insn == 0
                   1372:          || GET_CODE (insn) == CALL_INSN || GET_CODE (insn) == JUMP_INSN
                   1373:          || (GET_CODE (insn) == INSN
                   1374:              && (! reload_completed
                   1375:                  || (GET_CODE (PATTERN (insn)) != USE
                   1376:                      && GET_CODE (PATTERN (insn)) != CLOBBER))))
                   1377:        break;
                   1378:     }
                   1379: 
                   1380:   return insn;
                   1381: }
                   1382: 
                   1383: /* Find the last insn before INSN that really does something.  This routine
                   1384:    does not look inside SEQUENCEs.  Until reload has completed, this is the
                   1385:    same as prev_real_insn.  */
                   1386: 
                   1387: rtx
                   1388: prev_active_insn (insn)
                   1389:      rtx insn;
                   1390: {
                   1391:   while (insn)
                   1392:     {
                   1393:       insn = PREV_INSN (insn);
                   1394:       if (insn == 0
                   1395:          || GET_CODE (insn) == CALL_INSN || GET_CODE (insn) == JUMP_INSN
                   1396:          || (GET_CODE (insn) == INSN
                   1397:              && (! reload_completed
                   1398:                  || (GET_CODE (PATTERN (insn)) != USE
                   1399:                      && GET_CODE (PATTERN (insn)) != CLOBBER))))
                   1400:        break;
                   1401:     }
                   1402: 
                   1403:   return insn;
                   1404: }
                   1405: 
                   1406: /* Return the next CODE_LABEL after the insn INSN, or 0 if there is none.  */
                   1407: 
                   1408: rtx
                   1409: next_label (insn)
                   1410:      rtx insn;
                   1411: {
                   1412:   while (insn)
                   1413:     {
                   1414:       insn = NEXT_INSN (insn);
                   1415:       if (insn == 0 || GET_CODE (insn) == CODE_LABEL)
                   1416:        break;
                   1417:     }
                   1418: 
                   1419:   return insn;
                   1420: }
                   1421: 
                   1422: /* Return the last CODE_LABEL before the insn INSN, or 0 if there is none.  */
                   1423: 
                   1424: rtx
                   1425: prev_label (insn)
                   1426:      rtx insn;
                   1427: {
                   1428:   while (insn)
                   1429:     {
                   1430:       insn = PREV_INSN (insn);
                   1431:       if (insn == 0 || GET_CODE (insn) == CODE_LABEL)
                   1432:        break;
                   1433:     }
                   1434: 
                   1435:   return insn;
                   1436: }
                   1437: 
                   1438: #ifdef HAVE_cc0
                   1439: /* Return the next insn that uses CC0 after INSN, which is assumed to
                   1440:    set it.  This is the inverse of prev_cc0_setter (i.e., prev_cc0_setter
                   1441:    applied to the result of this function should yield INSN).
                   1442: 
                   1443:    Normally, this is simply the next insn.  However, if a REG_CC_USER note
                   1444:    is present, it contains the insn that uses CC0.
                   1445: 
                   1446:    Return 0 if we can't find the insn.  */
                   1447: 
                   1448: rtx
                   1449: next_cc0_user (insn)
                   1450:      rtx insn;
                   1451: {
                   1452:   rtx note = find_reg_note (insn, REG_CC_USER, 0);
                   1453: 
                   1454:   if (note)
                   1455:     return XEXP (note, 0);
                   1456: 
                   1457:   insn = next_nonnote_insn (insn);
                   1458:   if (insn && GET_CODE (insn) == INSN && GET_CODE (PATTERN (insn)) == SEQUENCE)
                   1459:     insn = XVECEXP (PATTERN (insn), 0, 0);
                   1460: 
                   1461:   if (insn && GET_RTX_CLASS (GET_CODE (insn)) == 'i'
                   1462:       && reg_mentioned_p (cc0_rtx, PATTERN (insn)))
                   1463:     return insn;
                   1464: 
                   1465:   return 0;
                   1466: }
                   1467: 
                   1468: /* Find the insn that set CC0 for INSN.  Unless INSN has a REG_CC_SETTER
                   1469:    note, it is the previous insn.  */
                   1470: 
                   1471: rtx
                   1472: prev_cc0_setter (insn)
                   1473:      rtx insn;
                   1474: {
                   1475:   rtx note = find_reg_note (insn, REG_CC_SETTER, 0);
                   1476:   rtx link;
                   1477: 
                   1478:   if (note)
                   1479:     return XEXP (note, 0);
                   1480: 
                   1481:   insn = prev_nonnote_insn (insn);
                   1482:   if (! sets_cc0_p (PATTERN (insn)))
                   1483:     abort ();
                   1484: 
                   1485:   return insn;
                   1486: }
                   1487: #endif
                   1488: 
                   1489: /* Try splitting insns that can be split for better scheduling.
                   1490:    PAT is the pattern which might split.
                   1491:    TRIAL is the insn providing PAT.
                   1492:    BACKWARDS is non-zero if we are scanning insns from last to first.
                   1493: 
                   1494:    If this routine succeeds in splitting, it returns the first or last
                   1495:    replacement insn depending on the value of BACKWARDS.  Otherwise, it
                   1496:    returns TRIAL.  If the insn to be returned can be split, it will be.  */
                   1497: 
                   1498: rtx
                   1499: try_split (pat, trial, backwards)
                   1500:      rtx pat, trial;
                   1501:      int backwards;
                   1502: {
                   1503:   rtx before = PREV_INSN (trial);
                   1504:   rtx after = NEXT_INSN (trial);
                   1505:   rtx seq = split_insns (pat, trial);
                   1506:   int has_barrier = 0;
                   1507:   rtx tem;
                   1508: 
                   1509:   /* If we are splitting a JUMP_INSN, it might be followed by a BARRIER.
                   1510:      We may need to handle this specially.  */
                   1511:   if (after && GET_CODE (after) == BARRIER)
                   1512:     {
                   1513:       has_barrier = 1;
                   1514:       after = NEXT_INSN (after);
                   1515:     }
                   1516: 
                   1517:   if (seq)
                   1518:     {
                   1519:       /* SEQ can either be a SEQUENCE or the pattern of a single insn.
                   1520:         The latter case will normally arise only when being done so that
                   1521:         it, in turn, will be split (SFmode on the 29k is an example).  */
                   1522:       if (GET_CODE (seq) == SEQUENCE)
                   1523:        {
                   1524:          /* If we are splitting a JUMP_INSN, look for the JUMP_INSN in
                   1525:             SEQ and copy our JUMP_LABEL to it.  If JUMP_LABEL is non-zero,
                   1526:             increment the usage count so we don't delete the label.  */
                   1527:          int i;
                   1528: 
                   1529:          if (GET_CODE (trial) == JUMP_INSN)
                   1530:            for (i = XVECLEN (seq, 0) - 1; i >= 0; i--)
                   1531:              if (GET_CODE (XVECEXP (seq, 0, i)) == JUMP_INSN)
                   1532:                {
                   1533:                  JUMP_LABEL (XVECEXP (seq, 0, i)) = JUMP_LABEL (trial);
                   1534: 
                   1535:                  if (JUMP_LABEL (trial))
                   1536:                    LABEL_NUSES (JUMP_LABEL (trial))++;
                   1537:                }
                   1538: 
                   1539:          tem = emit_insn_after (seq, before);
                   1540: 
                   1541:          delete_insn (trial);
                   1542:          if (has_barrier)
                   1543:            emit_barrier_after (tem);
                   1544:        }
                   1545:       /* Avoid infinite loop if the result matches the original pattern.  */
                   1546:       else if (rtx_equal_p (seq, pat))
                   1547:        return trial;
                   1548:       else
                   1549:        {
                   1550:          PATTERN (trial) = seq;
                   1551:          INSN_CODE (trial) = -1;
                   1552:        }
                   1553: 
                   1554:       /* Set TEM to the insn we should return.  */
                   1555:       tem = backwards ? prev_active_insn (after) : next_active_insn (before);
                   1556:       return try_split (PATTERN (tem), tem, backwards);
                   1557:     }
                   1558: 
                   1559:   return trial;
                   1560: }
                   1561: 
                   1562: /* Make and return an INSN rtx, initializing all its slots.
                   1563:    Store PATTERN in the pattern slots.
                   1564:    PAT_FORMALS is an idea that never really went anywhere.  */
                   1565: 
                   1566: rtx
                   1567: make_insn_raw (pattern, pat_formals)
                   1568:      rtx pattern;
                   1569:      rtvec pat_formals;
                   1570: {
                   1571:   register rtx insn;
                   1572: 
                   1573:   insn = rtx_alloc(INSN);
                   1574:   INSN_UID(insn) = cur_insn_uid++;
                   1575: 
                   1576:   PATTERN (insn) = pattern;
                   1577:   INSN_CODE (insn) = -1;
                   1578:   LOG_LINKS(insn) = NULL;
                   1579:   REG_NOTES(insn) = NULL;
                   1580: 
                   1581:   return insn;
                   1582: }
                   1583: 
                   1584: /* Like `make_insn' but make a JUMP_INSN instead of an insn.  */
                   1585: 
                   1586: static rtx
                   1587: make_jump_insn_raw (pattern, pat_formals)
                   1588:      rtx pattern;
                   1589:      rtvec pat_formals;
                   1590: {
                   1591:   register rtx insn;
                   1592: 
                   1593:   insn = rtx_alloc(JUMP_INSN);
                   1594:   INSN_UID(insn) = cur_insn_uid++;
                   1595: 
                   1596:   PATTERN (insn) = pattern;
                   1597:   INSN_CODE (insn) = -1;
                   1598:   LOG_LINKS(insn) = NULL;
                   1599:   REG_NOTES(insn) = NULL;
                   1600:   JUMP_LABEL(insn) = NULL;
                   1601: 
                   1602:   return insn;
                   1603: }
                   1604: 
                   1605: /* Add INSN to the end of the doubly-linked list.
                   1606:    INSN may be an INSN, JUMP_INSN, CALL_INSN, CODE_LABEL, BARRIER or NOTE.  */
                   1607: 
                   1608: void
                   1609: add_insn (insn)
                   1610:      register rtx insn;
                   1611: {
                   1612:   PREV_INSN (insn) = last_insn;
                   1613:   NEXT_INSN (insn) = 0;
                   1614: 
                   1615:   if (NULL != last_insn)
                   1616:     NEXT_INSN (last_insn) = insn;
                   1617: 
                   1618:   if (NULL == first_insn)
                   1619:     first_insn = insn;
                   1620: 
                   1621:   last_insn = insn;
                   1622: }
                   1623: 
                   1624: /* Add INSN into the doubly-linked list after insn AFTER.  This should be the
                   1625:    only function called to insert an insn once delay slots have been filled
                   1626:    since only it knows how to update a SEQUENCE.  */
                   1627: 
                   1628: void
                   1629: add_insn_after (insn, after)
                   1630:      rtx insn, after;
                   1631: {
                   1632:   rtx next = NEXT_INSN (after);
                   1633: 
                   1634:   NEXT_INSN (insn) = next;
                   1635:   PREV_INSN (insn) = after;
                   1636: 
                   1637:   if (next)
                   1638:     {
                   1639:       PREV_INSN (next) = insn;
                   1640:       if (GET_CODE (next) == INSN && GET_CODE (PATTERN (next)) == SEQUENCE)
                   1641:        PREV_INSN (XVECEXP (PATTERN (next), 0, 0)) = insn;
                   1642:     }
                   1643:   else if (last_insn == after)
                   1644:     last_insn = insn;
                   1645:   else
                   1646:     {
                   1647:       struct sequence_stack *stack = sequence_stack;
                   1648:       /* Scan all pending sequences too.  */
                   1649:       for (; stack; stack = stack->next)
                   1650:        if (after == stack->last)
                   1651:          stack->last = insn;
                   1652:     }
                   1653: 
                   1654:   NEXT_INSN (after) = insn;
                   1655:   if (GET_CODE (after) == INSN && GET_CODE (PATTERN (after)) == SEQUENCE)
                   1656:     {
                   1657:       rtx sequence = PATTERN (after);
                   1658:       NEXT_INSN (XVECEXP (sequence, 0, XVECLEN (sequence, 0) - 1)) = insn;
                   1659:     }
                   1660: }
                   1661: 
                   1662: /* Delete all insns made since FROM.
                   1663:    FROM becomes the new last instruction.  */
                   1664: 
                   1665: void
                   1666: delete_insns_since (from)
                   1667:      rtx from;
                   1668: {
                   1669:   if (from == 0)
                   1670:     first_insn = 0;
                   1671:   else
                   1672:     NEXT_INSN (from) = 0;
                   1673:   last_insn = from;
                   1674: }
                   1675: 
                   1676: /* Move a consecutive bunch of insns to a different place in the chain.
                   1677:    The insns to be moved are those between FROM and TO.
                   1678:    They are moved to a new position after the insn AFTER.
                   1679:    AFTER must not be FROM or TO or any insn in between.
                   1680: 
                   1681:    This function does not know about SEQUENCEs and hence should not be
                   1682:    called after delay-slot filling has been done.  */
                   1683: 
                   1684: void
                   1685: reorder_insns (from, to, after)
                   1686:      rtx from, to, after;
                   1687: {
                   1688:   /* Splice this bunch out of where it is now.  */
                   1689:   if (PREV_INSN (from))
                   1690:     NEXT_INSN (PREV_INSN (from)) = NEXT_INSN (to);
                   1691:   if (NEXT_INSN (to))
                   1692:     PREV_INSN (NEXT_INSN (to)) = PREV_INSN (from);
                   1693:   if (last_insn == to)
                   1694:     last_insn = PREV_INSN (from);
                   1695:   if (first_insn == from)
                   1696:     first_insn = NEXT_INSN (to);
                   1697: 
                   1698:   /* Make the new neighbors point to it and it to them.  */
                   1699:   if (NEXT_INSN (after))
                   1700:     PREV_INSN (NEXT_INSN (after)) = to;
                   1701: 
                   1702:   NEXT_INSN (to) = NEXT_INSN (after);
                   1703:   PREV_INSN (from) = after;
                   1704:   NEXT_INSN (after) = from;
                   1705:   if (after == last_insn)
                   1706:     last_insn = to;
                   1707: }
                   1708: 
                   1709: /* Return the line note insn preceding INSN.  */
                   1710: 
                   1711: static rtx
                   1712: find_line_note (insn)
                   1713:      rtx insn;
                   1714: {
                   1715:   if (no_line_numbers)
                   1716:     return 0;
                   1717: 
                   1718:   for (; insn; insn = PREV_INSN (insn))
                   1719:     if (GET_CODE (insn) == NOTE
                   1720:         && NOTE_LINE_NUMBER (insn) >= 0)
                   1721:       break;
                   1722: 
                   1723:   return insn;
                   1724: }
                   1725: 
                   1726: /* Like reorder_insns, but inserts line notes to preserve the line numbers
                   1727:    of the moved insns when debugging.  This may insert a note between AFTER
                   1728:    and FROM, and another one after TO.  */
                   1729: 
                   1730: void
                   1731: reorder_insns_with_line_notes (from, to, after)
                   1732:      rtx from, to, after;
                   1733: {
                   1734:   rtx from_line = find_line_note (from);
                   1735:   rtx after_line = find_line_note (after);
                   1736: 
                   1737:   reorder_insns (from, to, after);
                   1738: 
                   1739:   if (from_line == after_line)
                   1740:     return;
                   1741: 
                   1742:   if (from_line)
                   1743:     emit_line_note_after (NOTE_SOURCE_FILE (from_line),
                   1744:                          NOTE_LINE_NUMBER (from_line),
                   1745:                          after);
                   1746:   if (after_line)
                   1747:     emit_line_note_after (NOTE_SOURCE_FILE (after_line),
                   1748:                          NOTE_LINE_NUMBER (after_line),
                   1749:                          to);
                   1750: }
                   1751: 
                   1752: /* Emit an insn of given code and pattern
                   1753:    at a specified place within the doubly-linked list.  */
                   1754: 
                   1755: /* Make an instruction with body PATTERN
                   1756:    and output it before the instruction BEFORE.  */
                   1757: 
                   1758: rtx
                   1759: emit_insn_before (pattern, before)
                   1760:      register rtx pattern, before;
                   1761: {
                   1762:   register rtx insn = before;
                   1763: 
                   1764:   if (GET_CODE (pattern) == SEQUENCE)
                   1765:     {
                   1766:       register int i;
                   1767: 
                   1768:       for (i = 0; i < XVECLEN (pattern, 0); i++)
                   1769:        {
                   1770:          insn = XVECEXP (pattern, 0, i);
                   1771:          add_insn_after (insn, PREV_INSN (before));
                   1772:        }
                   1773:       if (XVECLEN (pattern, 0) < SEQUENCE_RESULT_SIZE)
                   1774:        sequence_result[XVECLEN (pattern, 0)] = pattern;
                   1775:     }
                   1776:   else
                   1777:     {
                   1778:       insn = make_insn_raw (pattern, 0);
                   1779:       add_insn_after (insn, PREV_INSN (before));
                   1780:     }
                   1781: 
                   1782:   return insn;
                   1783: }
                   1784: 
                   1785: /* Make an instruction with body PATTERN and code JUMP_INSN
                   1786:    and output it before the instruction BEFORE.  */
                   1787: 
                   1788: rtx
                   1789: emit_jump_insn_before (pattern, before)
                   1790:      register rtx pattern, before;
                   1791: {
                   1792:   register rtx insn;
                   1793: 
                   1794:   if (GET_CODE (pattern) == SEQUENCE)
                   1795:     insn = emit_insn_before (pattern, before);
                   1796:   else
                   1797:     {
                   1798:       insn = make_jump_insn_raw (pattern, 0);
                   1799:       add_insn_after (insn, PREV_INSN (before));
                   1800:     }
                   1801: 
                   1802:   return insn;
                   1803: }
                   1804: 
                   1805: /* Make an instruction with body PATTERN and code CALL_INSN
                   1806:    and output it before the instruction BEFORE.  */
                   1807: 
                   1808: rtx
                   1809: emit_call_insn_before (pattern, before)
                   1810:      register rtx pattern, before;
                   1811: {
                   1812:   rtx insn = emit_insn_before (pattern, before);
                   1813:   PUT_CODE (insn, CALL_INSN);
                   1814:   return insn;
                   1815: }
                   1816: 
                   1817: /* Make an insn of code BARRIER
                   1818:    and output it before the insn AFTER.  */
                   1819: 
                   1820: rtx
                   1821: emit_barrier_before (before)
                   1822:      register rtx before;
                   1823: {
                   1824:   register rtx insn = rtx_alloc (BARRIER);
                   1825: 
                   1826:   INSN_UID (insn) = cur_insn_uid++;
                   1827: 
                   1828:   add_insn_after (insn, PREV_INSN (before));
                   1829:   return insn;
                   1830: }
                   1831: 
                   1832: /* Emit a note of subtype SUBTYPE before the insn BEFORE.  */
                   1833: 
                   1834: rtx
                   1835: emit_note_before (subtype, before)
                   1836:      int subtype;
                   1837:      rtx before;
                   1838: {
                   1839:   register rtx note = rtx_alloc (NOTE);
                   1840:   INSN_UID (note) = cur_insn_uid++;
                   1841:   NOTE_SOURCE_FILE (note) = 0;
                   1842:   NOTE_LINE_NUMBER (note) = subtype;
                   1843: 
                   1844:   add_insn_after (note, PREV_INSN (before));
                   1845:   return note;
                   1846: }
                   1847: 
                   1848: /* Make an insn of code INSN with body PATTERN
                   1849:    and output it after the insn AFTER.  */
                   1850: 
                   1851: rtx
                   1852: emit_insn_after (pattern, after)
                   1853:      register rtx pattern, after;
                   1854: {
                   1855:   register rtx insn = after;
                   1856: 
                   1857:   if (GET_CODE (pattern) == SEQUENCE)
                   1858:     {
                   1859:       register int i;
                   1860: 
                   1861:       for (i = 0; i < XVECLEN (pattern, 0); i++)
                   1862:        {
                   1863:          insn = XVECEXP (pattern, 0, i);
                   1864:          add_insn_after (insn, after);
                   1865:          after = insn;
                   1866:        }
                   1867:       if (XVECLEN (pattern, 0) < SEQUENCE_RESULT_SIZE)
                   1868:        sequence_result[XVECLEN (pattern, 0)] = pattern;
                   1869:     }
                   1870:   else
                   1871:     {
                   1872:       insn = make_insn_raw (pattern, 0);
                   1873:       add_insn_after (insn, after);
                   1874:     }
                   1875: 
                   1876:   return insn;
                   1877: }
                   1878: 
                   1879: /* Make an insn of code JUMP_INSN with body PATTERN
                   1880:    and output it after the insn AFTER.  */
                   1881: 
                   1882: rtx
                   1883: emit_jump_insn_after (pattern, after)
                   1884:      register rtx pattern, after;
                   1885: {
                   1886:   register rtx insn;
                   1887: 
                   1888:   if (GET_CODE (pattern) == SEQUENCE)
                   1889:     insn = emit_insn_after (pattern, after);
                   1890:   else
                   1891:     {
                   1892:       insn = make_jump_insn_raw (pattern, 0);
                   1893:       add_insn_after (insn, after);
                   1894:     }
                   1895: 
                   1896:   return insn;
                   1897: }
                   1898: 
                   1899: /* Make an insn of code BARRIER
                   1900:    and output it after the insn AFTER.  */
                   1901: 
                   1902: rtx
                   1903: emit_barrier_after (after)
                   1904:      register rtx after;
                   1905: {
                   1906:   register rtx insn = rtx_alloc (BARRIER);
                   1907: 
                   1908:   INSN_UID (insn) = cur_insn_uid++;
                   1909: 
                   1910:   add_insn_after (insn, after);
                   1911:   return insn;
                   1912: }
                   1913: 
                   1914: /* Emit the label LABEL after the insn AFTER.  */
                   1915: 
                   1916: rtx
                   1917: emit_label_after (label, after)
                   1918:      rtx label, after;
                   1919: {
                   1920:   /* This can be called twice for the same label
                   1921:      as a result of the confusion that follows a syntax error!
                   1922:      So make it harmless.  */
                   1923:   if (INSN_UID (label) == 0)
                   1924:     {
                   1925:       INSN_UID (label) = cur_insn_uid++;
                   1926:       add_insn_after (label, after);
                   1927:     }
                   1928: 
                   1929:   return label;
                   1930: }
                   1931: 
                   1932: /* Emit a note of subtype SUBTYPE after the insn AFTER.  */
                   1933: 
                   1934: rtx
                   1935: emit_note_after (subtype, after)
                   1936:      int subtype;
                   1937:      rtx after;
                   1938: {
                   1939:   register rtx note = rtx_alloc (NOTE);
                   1940:   INSN_UID (note) = cur_insn_uid++;
                   1941:   NOTE_SOURCE_FILE (note) = 0;
                   1942:   NOTE_LINE_NUMBER (note) = subtype;
                   1943:   add_insn_after (note, after);
                   1944:   return note;
                   1945: }
                   1946: 
                   1947: /* Emit a line note for FILE and LINE after the insn AFTER.  */
                   1948: 
                   1949: rtx
                   1950: emit_line_note_after (file, line, after)
                   1951:      char *file;
                   1952:      int line;
                   1953:      rtx after;
                   1954: {
                   1955:   register rtx note;
                   1956: 
                   1957:   if (no_line_numbers && line > 0)
                   1958:     {
                   1959:       cur_insn_uid++;
                   1960:       return 0;
                   1961:     }
                   1962: 
                   1963:   note  = rtx_alloc (NOTE);
                   1964:   INSN_UID (note) = cur_insn_uid++;
                   1965:   NOTE_SOURCE_FILE (note) = file;
                   1966:   NOTE_LINE_NUMBER (note) = line;
                   1967:   add_insn_after (note, after);
                   1968:   return note;
                   1969: }
                   1970: 
                   1971: /* Make an insn of code INSN with pattern PATTERN
                   1972:    and add it to the end of the doubly-linked list.
                   1973:    If PATTERN is a SEQUENCE, take the elements of it
                   1974:    and emit an insn for each element.
                   1975: 
                   1976:    Returns the last insn emitted.  */
                   1977: 
                   1978: rtx
                   1979: emit_insn (pattern)
                   1980:      rtx pattern;
                   1981: {
                   1982:   rtx insn = last_insn;
                   1983: 
                   1984:   if (GET_CODE (pattern) == SEQUENCE)
                   1985:     {
                   1986:       register int i;
                   1987: 
                   1988:       for (i = 0; i < XVECLEN (pattern, 0); i++)
                   1989:        {
                   1990:          insn = XVECEXP (pattern, 0, i);
                   1991:          add_insn (insn);
                   1992:        }
                   1993:       if (XVECLEN (pattern, 0) < SEQUENCE_RESULT_SIZE)
                   1994:        sequence_result[XVECLEN (pattern, 0)] = pattern;
                   1995:     }
                   1996:   else
                   1997:     {
                   1998:       insn = make_insn_raw (pattern, NULL);
                   1999:       add_insn (insn);
                   2000:     }
                   2001: 
                   2002:   return insn;
                   2003: }
                   2004: 
                   2005: /* Emit the insns in a chain starting with INSN.
                   2006:    Return the last insn emitted.  */
                   2007: 
                   2008: rtx
                   2009: emit_insns (insn)
                   2010:      rtx insn;
                   2011: {
                   2012:   rtx last = 0;
                   2013: 
                   2014:   while (insn)
                   2015:     {
                   2016:       rtx next = NEXT_INSN (insn);
                   2017:       add_insn (insn);
                   2018:       last = insn;
                   2019:       insn = next;
                   2020:     }
                   2021: 
                   2022:   return last;
                   2023: }
                   2024: 
                   2025: /* Emit the insns in a chain starting with INSN and place them in front of
                   2026:    the insn BEFORE.  Return the last insn emitted.  */
                   2027: 
                   2028: rtx
                   2029: emit_insns_before (insn, before)
                   2030:      rtx insn;
                   2031:      rtx before;
                   2032: {
                   2033:   rtx last = 0;
                   2034: 
                   2035:   while (insn)
                   2036:     {
                   2037:       rtx next = NEXT_INSN (insn);
                   2038:       add_insn_after (insn, PREV_INSN (before));
                   2039:       last = insn;
                   2040:       insn = next;
                   2041:     }
                   2042: 
                   2043:   return last;
                   2044: }
                   2045: 
                   2046: /* Make an insn of code JUMP_INSN with pattern PATTERN
                   2047:    and add it to the end of the doubly-linked list.  */
                   2048: 
                   2049: rtx
                   2050: emit_jump_insn (pattern)
                   2051:      rtx pattern;
                   2052: {
                   2053:   if (GET_CODE (pattern) == SEQUENCE)
                   2054:     return emit_insn (pattern);
                   2055:   else
                   2056:     {
                   2057:       register rtx insn = make_jump_insn_raw (pattern, NULL);
                   2058:       add_insn (insn);
                   2059:       return insn;
                   2060:     }
                   2061: }
                   2062: 
                   2063: /* Make an insn of code CALL_INSN with pattern PATTERN
                   2064:    and add it to the end of the doubly-linked list.  */
                   2065: 
                   2066: rtx
                   2067: emit_call_insn (pattern)
                   2068:      rtx pattern;
                   2069: {
                   2070:   if (GET_CODE (pattern) == SEQUENCE)
                   2071:     return emit_insn (pattern);
                   2072:   else
                   2073:     {
                   2074:       register rtx insn = make_insn_raw (pattern, NULL);
                   2075:       add_insn (insn);
                   2076:       PUT_CODE (insn, CALL_INSN);
                   2077:       return insn;
                   2078:     }
                   2079: }
                   2080: 
                   2081: /* Add the label LABEL to the end of the doubly-linked list.  */
                   2082: 
                   2083: rtx
                   2084: emit_label (label)
                   2085:      rtx label;
                   2086: {
                   2087:   /* This can be called twice for the same label
                   2088:      as a result of the confusion that follows a syntax error!
                   2089:      So make it harmless.  */
                   2090:   if (INSN_UID (label) == 0)
                   2091:     {
                   2092:       INSN_UID (label) = cur_insn_uid++;
                   2093:       add_insn (label);
                   2094:     }
                   2095:   return label;
                   2096: }
                   2097: 
                   2098: /* Make an insn of code BARRIER
                   2099:    and add it to the end of the doubly-linked list.  */
                   2100: 
                   2101: rtx
                   2102: emit_barrier ()
                   2103: {
                   2104:   register rtx barrier = rtx_alloc (BARRIER);
                   2105:   INSN_UID (barrier) = cur_insn_uid++;
                   2106:   add_insn (barrier);
                   2107:   return barrier;
                   2108: }
                   2109: 
                   2110: /* Make an insn of code NOTE
                   2111:    with data-fields specified by FILE and LINE
                   2112:    and add it to the end of the doubly-linked list,
                   2113:    but only if line-numbers are desired for debugging info.  */
                   2114: 
                   2115: rtx
                   2116: emit_line_note (file, line)
                   2117:      char *file;
                   2118:      int line;
                   2119: {
                   2120:   emit_filename = file;
                   2121:   emit_lineno = line;
                   2122: 
                   2123: #if 0
                   2124:   if (no_line_numbers)
                   2125:     return 0;
                   2126: #endif
                   2127: 
                   2128:   return emit_note (file, line);
                   2129: }
                   2130: 
                   2131: /* Make an insn of code NOTE
                   2132:    with data-fields specified by FILE and LINE
                   2133:    and add it to the end of the doubly-linked list.
                   2134:    If it is a line-number NOTE, omit it if it matches the previous one.  */
                   2135: 
                   2136: rtx
                   2137: emit_note (file, line)
                   2138:      char *file;
                   2139:      int line;
                   2140: {
                   2141:   register rtx note;
                   2142: 
                   2143:   if (line > 0)
                   2144:     {
                   2145:       if (file && last_filename && !strcmp (file, last_filename)
                   2146:          && line == last_linenum)
                   2147:        return 0;
                   2148:       last_filename = file;
                   2149:       last_linenum = line;
                   2150:     }
                   2151: 
                   2152:   if (no_line_numbers && line > 0)
                   2153:     {
                   2154:       cur_insn_uid++;
                   2155:       return 0;
                   2156:     }
                   2157: 
                   2158:   note = rtx_alloc (NOTE);
                   2159:   INSN_UID (note) = cur_insn_uid++;
                   2160:   NOTE_SOURCE_FILE (note) = file;
                   2161:   NOTE_LINE_NUMBER (note) = line;
                   2162:   add_insn (note);
                   2163:   return note;
                   2164: }
                   2165: 
                   2166: /* Emit a NOTE, and don't omit it even if LINE it the previous note.  */
                   2167: 
                   2168: rtx
                   2169: emit_line_note_force (file, line)
                   2170:      char *file;
                   2171:      int line;
                   2172: {
                   2173:   last_linenum = -1;
                   2174:   return emit_line_note (file, line);
                   2175: }
                   2176: 
                   2177: /* Cause next statement to emit a line note even if the line number
                   2178:    has not changed.  This is used at the beginning of a function.  */
                   2179: 
                   2180: void
                   2181: force_next_line_note ()
                   2182: {
                   2183:   last_linenum = -1;
                   2184: }
                   2185: 
                   2186: /* Return an indication of which type of insn should have X as a body.
                   2187:    The value is CODE_LABEL, INSN, CALL_INSN or JUMP_INSN.  */
                   2188: 
                   2189: enum rtx_code
                   2190: classify_insn (x)
                   2191:      rtx x;
                   2192: {
                   2193:   if (GET_CODE (x) == CODE_LABEL)
                   2194:     return CODE_LABEL;
                   2195:   if (GET_CODE (x) == CALL)
                   2196:     return CALL_INSN;
                   2197:   if (GET_CODE (x) == RETURN)
                   2198:     return JUMP_INSN;
                   2199:   if (GET_CODE (x) == SET)
                   2200:     {
                   2201:       if (SET_DEST (x) == pc_rtx)
                   2202:        return JUMP_INSN;
                   2203:       else if (GET_CODE (SET_SRC (x)) == CALL)
                   2204:        return CALL_INSN;
                   2205:       else
                   2206:        return INSN;
                   2207:     }
                   2208:   if (GET_CODE (x) == PARALLEL)
                   2209:     {
                   2210:       register int j;
                   2211:       for (j = XVECLEN (x, 0) - 1; j >= 0; j--)
                   2212:        if (GET_CODE (XVECEXP (x, 0, j)) == CALL)
                   2213:          return CALL_INSN;
                   2214:        else if (GET_CODE (XVECEXP (x, 0, j)) == SET
                   2215:                 && SET_DEST (XVECEXP (x, 0, j)) == pc_rtx)
                   2216:          return JUMP_INSN;
                   2217:        else if (GET_CODE (XVECEXP (x, 0, j)) == SET
                   2218:                 && GET_CODE (SET_SRC (XVECEXP (x, 0, j))) == CALL)
                   2219:          return CALL_INSN;
                   2220:     }
                   2221:   return INSN;
                   2222: }
                   2223: 
                   2224: /* Emit the rtl pattern X as an appropriate kind of insn.
                   2225:    If X is a label, it is simply added into the insn chain.  */
                   2226: 
                   2227: rtx
                   2228: emit (x)
                   2229:      rtx x;
                   2230: {
                   2231:   enum rtx_code code = classify_insn (x);
                   2232: 
                   2233:   if (code == CODE_LABEL)
                   2234:     return emit_label (x);
                   2235:   else if (code == INSN)
                   2236:     return emit_insn (x);
                   2237:   else if (code == JUMP_INSN)
                   2238:     {
                   2239:       register rtx insn = emit_jump_insn (x);
                   2240:       if (simplejump_p (insn) || GET_CODE (x) == RETURN)
                   2241:        return emit_barrier ();
                   2242:       return insn;
                   2243:     }
                   2244:   else if (code == CALL_INSN)
                   2245:     return emit_call_insn (x);
                   2246:   else
                   2247:     abort ();
                   2248: }
                   2249: 
                   2250: /* Begin emitting insns to a sequence which can be packaged in an RTL_EXPR.  */
                   2251: 
                   2252: void
                   2253: start_sequence ()
                   2254: {
                   2255:   struct sequence_stack *tem;
                   2256: 
                   2257:   if (sequence_element_free_list)
                   2258:     {
                   2259:       /* Reuse a previously-saved struct sequence_stack.  */
                   2260:       tem = sequence_element_free_list;
                   2261:       sequence_element_free_list = tem->next;
                   2262:     }
                   2263:   else
                   2264:     tem = (struct sequence_stack *) permalloc (sizeof (struct sequence_stack));
                   2265: 
                   2266:   tem->next = sequence_stack;
                   2267:   tem->first = first_insn;
                   2268:   tem->last = last_insn;
                   2269: 
                   2270:   sequence_stack = tem;
                   2271: 
                   2272:   first_insn = 0;
                   2273:   last_insn = 0;
                   2274: }
                   2275: 
                   2276: /* Set up the insn chain starting with FIRST
                   2277:    as the current sequence, saving the previously current one.  */
                   2278: 
                   2279: void
                   2280: push_to_sequence (first)
                   2281:      rtx first;
                   2282: {
                   2283:   rtx last;
                   2284: 
                   2285:   start_sequence ();
                   2286: 
                   2287:   for (last = first; last && NEXT_INSN (last); last = NEXT_INSN (last));
                   2288: 
                   2289:   first_insn = first;
                   2290:   last_insn = last;
                   2291: }
                   2292: 
                   2293: /* After emitting to a sequence, restore previous saved state.
                   2294: 
                   2295:    To get the contents of the sequence just made,
                   2296:    you must call `gen_sequence' *before* calling here.  */
                   2297: 
                   2298: void
                   2299: end_sequence ()
                   2300: {
                   2301:   struct sequence_stack *tem = sequence_stack;
                   2302: 
                   2303:   first_insn = tem->first;
                   2304:   last_insn = tem->last;
                   2305:   sequence_stack = tem->next;
                   2306: 
                   2307:   tem->next = sequence_element_free_list;
                   2308:   sequence_element_free_list = tem;
                   2309: }
                   2310: 
                   2311: /* Return 1 if currently emitting into a sequence.  */
                   2312: 
                   2313: int
                   2314: in_sequence_p ()
                   2315: {
                   2316:   return sequence_stack != 0;
                   2317: }
                   2318: 
                   2319: /* Generate a SEQUENCE rtx containing the insns already emitted
                   2320:    to the current sequence.
                   2321: 
                   2322:    This is how the gen_... function from a DEFINE_EXPAND
                   2323:    constructs the SEQUENCE that it returns.  */
                   2324: 
                   2325: rtx
                   2326: gen_sequence ()
                   2327: {
                   2328:   rtx result;
                   2329:   rtx tem;
                   2330:   rtvec newvec;
                   2331:   int i;
                   2332:   int len;
                   2333: 
                   2334:   /* Count the insns in the chain.  */
                   2335:   len = 0;
                   2336:   for (tem = first_insn; tem; tem = NEXT_INSN (tem))
                   2337:     len++;
                   2338: 
                   2339:   /* If only one insn, return its pattern rather than a SEQUENCE.
                   2340:      (Now that we cache SEQUENCE expressions, it isn't worth special-casing
                   2341:      the case of an empty list.)  */
                   2342:   if (len == 1
                   2343:       && (GET_CODE (first_insn) == INSN
                   2344:          || GET_CODE (first_insn) == JUMP_INSN
                   2345:          || GET_CODE (first_insn) == CALL_INSN))
                   2346:     return PATTERN (first_insn);
                   2347: 
                   2348:   /* Put them in a vector.  See if we already have a SEQUENCE of the
                   2349:      appropriate length around.  */
                   2350:   if (len < SEQUENCE_RESULT_SIZE && (result = sequence_result[len]) != 0)
                   2351:     sequence_result[len] = 0;
                   2352:   else
                   2353:     {
                   2354:       /* Ensure that this rtl goes in saveable_obstack, since we may be
                   2355:         caching it.  */
                   2356:       int in_current_obstack = rtl_in_saveable_obstack ();
                   2357:       result = gen_rtx (SEQUENCE, VOIDmode, rtvec_alloc (len));
                   2358:       if (in_current_obstack)
                   2359:        rtl_in_current_obstack ();
                   2360:     }
                   2361: 
                   2362:   for (i = 0, tem = first_insn; tem; tem = NEXT_INSN (tem), i++)
                   2363:     XVECEXP (result, 0, i) = tem;
                   2364: 
                   2365:   return result;
                   2366: }
                   2367: 
                   2368: /* Set up regno_reg_rtx, reg_rtx_no and regno_pointer_flag
                   2369:    according to the chain of insns starting with FIRST.
                   2370: 
                   2371:    Also set cur_insn_uid to exceed the largest uid in that chain.
                   2372: 
                   2373:    This is used when an inline function's rtl is saved
                   2374:    and passed to rest_of_compilation later.  */
                   2375: 
                   2376: static void restore_reg_data_1 ();
                   2377: 
                   2378: void
                   2379: restore_reg_data (first)
                   2380:      rtx first;
                   2381: {
                   2382:   register rtx insn;
                   2383:   int i;
                   2384:   register int max_uid = 0;
                   2385: 
                   2386:   for (insn = first; insn; insn = NEXT_INSN (insn))
                   2387:     {
                   2388:       if (INSN_UID (insn) >= max_uid)
                   2389:        max_uid = INSN_UID (insn);
                   2390: 
                   2391:       switch (GET_CODE (insn))
                   2392:        {
                   2393:        case NOTE:
                   2394:        case CODE_LABEL:
                   2395:        case BARRIER:
                   2396:          break;
                   2397: 
                   2398:        case JUMP_INSN:
                   2399:        case CALL_INSN:
                   2400:        case INSN:
                   2401:          restore_reg_data_1 (PATTERN (insn));
                   2402:          break;
                   2403:        }
                   2404:     }
                   2405: 
                   2406:   /* Don't duplicate the uids already in use.  */
                   2407:   cur_insn_uid = max_uid + 1;
                   2408: 
                   2409:   /* If any regs are missing, make them up.  
                   2410: 
                   2411:      ??? word_mode is not necessarily the right mode.  Most likely these REGs
                   2412:      are never used.  At some point this should be checked.  */
                   2413: 
                   2414:   for (i = FIRST_PSEUDO_REGISTER; i < reg_rtx_no; i++)
                   2415:     if (regno_reg_rtx[i] == 0)
                   2416:       regno_reg_rtx[i] = gen_rtx (REG, word_mode, i);
                   2417: }
                   2418: 
                   2419: static void
                   2420: restore_reg_data_1 (orig)
                   2421:      rtx orig;
                   2422: {
                   2423:   register rtx x = orig;
                   2424:   register int i;
                   2425:   register enum rtx_code code;
                   2426:   register char *format_ptr;
                   2427: 
                   2428:   code = GET_CODE (x);
                   2429: 
                   2430:   switch (code)
                   2431:     {
                   2432:     case QUEUED:
                   2433:     case CONST_INT:
                   2434:     case CONST_DOUBLE:
                   2435:     case SYMBOL_REF:
                   2436:     case CODE_LABEL:
                   2437:     case PC:
                   2438:     case CC0:
                   2439:     case LABEL_REF:
                   2440:       return;
                   2441: 
                   2442:     case REG:
                   2443:       if (REGNO (x) >= FIRST_PSEUDO_REGISTER)
                   2444:        {
                   2445:          /* Make sure regno_pointer_flag and regno_reg_rtx are large
                   2446:             enough to have an element for this pseudo reg number.  */
                   2447:          if (REGNO (x) >= reg_rtx_no)
                   2448:            {
                   2449:              reg_rtx_no = REGNO (x);
                   2450: 
                   2451:              if (reg_rtx_no >= regno_pointer_flag_length)
                   2452:                {
                   2453:                  int newlen = MAX (regno_pointer_flag_length * 2,
                   2454:                                    reg_rtx_no + 30);
                   2455:                  rtx *new1;
                   2456:                  char *new = (char *) oballoc (newlen);
                   2457:                  bzero (new, newlen);
                   2458:                  bcopy (regno_pointer_flag, new, regno_pointer_flag_length);
                   2459: 
                   2460:                  new1 = (rtx *) oballoc (newlen * sizeof (rtx));
                   2461:                  bzero (new1, newlen * sizeof (rtx));
                   2462:                  bcopy (regno_reg_rtx, new1, regno_pointer_flag_length * sizeof (rtx));
                   2463: 
                   2464:                  regno_pointer_flag = new;
                   2465:                  regno_reg_rtx = new1;
                   2466:                  regno_pointer_flag_length = newlen;
                   2467:                }
                   2468:              reg_rtx_no ++;
                   2469:            }
                   2470:          regno_reg_rtx[REGNO (x)] = x;
                   2471:        }
                   2472:       return;
                   2473: 
                   2474:     case MEM:
                   2475:       if (GET_CODE (XEXP (x, 0)) == REG)
                   2476:        mark_reg_pointer (XEXP (x, 0));
                   2477:       restore_reg_data_1 (XEXP (x, 0));
                   2478:       return;
                   2479:     }
                   2480: 
                   2481:   /* Now scan the subexpressions recursively.  */
                   2482: 
                   2483:   format_ptr = GET_RTX_FORMAT (code);
                   2484: 
                   2485:   for (i = 0; i < GET_RTX_LENGTH (code); i++)
                   2486:     {
                   2487:       switch (*format_ptr++)
                   2488:        {
                   2489:        case 'e':
                   2490:          restore_reg_data_1 (XEXP (x, i));
                   2491:          break;
                   2492: 
                   2493:        case 'E':
                   2494:          if (XVEC (x, i) != NULL)
                   2495:            {
                   2496:              register int j;
                   2497: 
                   2498:              for (j = 0; j < XVECLEN (x, i); j++)
                   2499:                restore_reg_data_1 (XVECEXP (x, i, j));
                   2500:            }
                   2501:          break;
                   2502:        }
                   2503:     }
                   2504: }
                   2505: 
                   2506: /* Initialize data structures and variables in this file
                   2507:    before generating rtl for each function.  */
                   2508: 
                   2509: void
                   2510: init_emit ()
                   2511: {
                   2512:   int i;
                   2513: 
                   2514:   first_insn = NULL;
                   2515:   last_insn = NULL;
                   2516:   cur_insn_uid = 1;
                   2517:   reg_rtx_no = LAST_VIRTUAL_REGISTER + 1;
                   2518:   last_linenum = 0;
                   2519:   last_filename = 0;
                   2520:   first_label_num = label_num;
                   2521:   last_label_num = 0;
                   2522: 
                   2523:   /* Clear the start_sequence/gen_sequence cache.  */
                   2524:   sequence_element_free_list = 0;
                   2525:   for (i = 0; i < SEQUENCE_RESULT_SIZE; i++)
                   2526:     sequence_result[i] = 0;
                   2527: 
                   2528:   /* Init the tables that describe all the pseudo regs.  */
                   2529: 
                   2530:   regno_pointer_flag_length = LAST_VIRTUAL_REGISTER + 101;
                   2531: 
                   2532:   regno_pointer_flag 
                   2533:     = (char *) oballoc (regno_pointer_flag_length);
                   2534:   bzero (regno_pointer_flag, regno_pointer_flag_length);
                   2535: 
                   2536:   regno_reg_rtx 
                   2537:     = (rtx *) oballoc (regno_pointer_flag_length * sizeof (rtx));
                   2538:   bzero (regno_reg_rtx, regno_pointer_flag_length * sizeof (rtx));
                   2539: 
                   2540:   /* Put copies of all the virtual register rtx into regno_reg_rtx.  */
                   2541:   regno_reg_rtx[VIRTUAL_INCOMING_ARGS_REGNUM] = virtual_incoming_args_rtx;
                   2542:   regno_reg_rtx[VIRTUAL_STACK_VARS_REGNUM] = virtual_stack_vars_rtx;
                   2543:   regno_reg_rtx[VIRTUAL_STACK_DYNAMIC_REGNUM] = virtual_stack_dynamic_rtx;
                   2544:   regno_reg_rtx[VIRTUAL_OUTGOING_ARGS_REGNUM] = virtual_outgoing_args_rtx;
                   2545: }
                   2546: 
                   2547: /* Create some permanent unique rtl objects shared between all functions.
                   2548:    LINE_NUMBERS is nonzero if line numbers are to be generated.  */
                   2549: 
                   2550: void
                   2551: init_emit_once (line_numbers)
                   2552:      int line_numbers;
                   2553: {
                   2554:   int i;
                   2555:   enum machine_mode mode;
                   2556: 
                   2557:   no_line_numbers = ! line_numbers;
                   2558: 
                   2559:   sequence_stack = NULL;
                   2560: 
                   2561:   /* Create the unique rtx's for certain rtx codes and operand values.  */
                   2562: 
                   2563:   pc_rtx = gen_rtx (PC, VOIDmode);
                   2564:   cc0_rtx = gen_rtx (CC0, VOIDmode);
                   2565: 
                   2566:   /* Don't use gen_rtx here since gen_rtx in this case
                   2567:      tries to use these variables.  */
                   2568:   for (i = - MAX_SAVED_CONST_INT; i <= MAX_SAVED_CONST_INT; i++)
                   2569:     {
                   2570:       const_int_rtx[i + MAX_SAVED_CONST_INT] = rtx_alloc (CONST_INT);
                   2571:       PUT_MODE (const_int_rtx[i + MAX_SAVED_CONST_INT], VOIDmode);
                   2572:       INTVAL (const_int_rtx[i + MAX_SAVED_CONST_INT]) = i;
                   2573:     }
                   2574: 
                   2575:   /* These four calls obtain some of the rtx expressions made above.  */
                   2576:   const0_rtx = gen_rtx (CONST_INT, VOIDmode, 0);
                   2577:   const1_rtx = gen_rtx (CONST_INT, VOIDmode, 1);
                   2578:   const2_rtx = gen_rtx (CONST_INT, VOIDmode, 2);
                   2579:   constm1_rtx = gen_rtx (CONST_INT, VOIDmode, -1);
                   2580: 
                   2581:   /* This will usually be one of the above constants, but may be a new rtx.  */
                   2582:   const_true_rtx = gen_rtx (CONST_INT, VOIDmode, STORE_FLAG_VALUE);
                   2583: 
                   2584:   dconst0 = REAL_VALUE_ATOF ("0");
                   2585:   dconst1 = REAL_VALUE_ATOF ("1");
                   2586:   dconst2 = REAL_VALUE_ATOF ("2");
                   2587:   dconstm1 = REAL_VALUE_ATOF ("-1");
                   2588: 
                   2589:   for (i = 0; i <= 2; i++)
                   2590:     {
                   2591:       for (mode = GET_CLASS_NARROWEST_MODE (MODE_FLOAT); mode != VOIDmode;
                   2592:           mode = GET_MODE_WIDER_MODE (mode))
                   2593:        {
                   2594:          rtx tem = rtx_alloc (CONST_DOUBLE);
                   2595:          union real_extract u;
                   2596: 
                   2597:          bzero (&u, sizeof u);  /* Zero any holes in a structure.  */
                   2598:          u.d = i == 0 ? dconst0 : i == 1 ? dconst1 : dconst2;
                   2599: 
                   2600:          bcopy (&u, &CONST_DOUBLE_LOW (tem), sizeof u);
                   2601:          CONST_DOUBLE_MEM (tem) = cc0_rtx;
                   2602:          PUT_MODE (tem, mode);
                   2603: 
                   2604:          const_tiny_rtx[i][(int) mode] = tem;
                   2605:        }
                   2606: 
                   2607:       const_tiny_rtx[i][VOIDmode] = gen_rtx (CONST_INT, VOIDmode, i);
                   2608: 
                   2609:       for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
                   2610:           mode = GET_MODE_WIDER_MODE (mode))
                   2611:        const_tiny_rtx[i][(int) mode] = gen_rtx (CONST_INT, VOIDmode, i);
                   2612:     }
                   2613: 
                   2614:   stack_pointer_rtx = gen_rtx (REG, Pmode, STACK_POINTER_REGNUM);
                   2615:   frame_pointer_rtx = gen_rtx (REG, Pmode, FRAME_POINTER_REGNUM);
                   2616: 
                   2617:   if (FRAME_POINTER_REGNUM == ARG_POINTER_REGNUM)
                   2618:     arg_pointer_rtx = frame_pointer_rtx;
                   2619:   else if (STACK_POINTER_REGNUM == ARG_POINTER_REGNUM)
                   2620:     arg_pointer_rtx = stack_pointer_rtx;
                   2621:   else
                   2622:     arg_pointer_rtx = gen_rtx (REG, Pmode, ARG_POINTER_REGNUM);
                   2623: 
                   2624:   /* Create the virtual registers.  Do so here since the following objects
                   2625:      might reference them.  */
                   2626: 
                   2627:   virtual_incoming_args_rtx = gen_rtx (REG, Pmode,
                   2628:                                       VIRTUAL_INCOMING_ARGS_REGNUM);
                   2629:   virtual_stack_vars_rtx = gen_rtx (REG, Pmode,
                   2630:                                    VIRTUAL_STACK_VARS_REGNUM);
                   2631:   virtual_stack_dynamic_rtx = gen_rtx (REG, Pmode,
                   2632:                                       VIRTUAL_STACK_DYNAMIC_REGNUM);
                   2633:   virtual_outgoing_args_rtx = gen_rtx (REG, Pmode,
                   2634:                                       VIRTUAL_OUTGOING_ARGS_REGNUM);
                   2635: 
                   2636: #ifdef STRUCT_VALUE
                   2637:   struct_value_rtx = STRUCT_VALUE;
                   2638: #else
                   2639:   struct_value_rtx = gen_rtx (REG, Pmode, STRUCT_VALUE_REGNUM);
                   2640: #endif
                   2641: 
                   2642: #ifdef STRUCT_VALUE_INCOMING
                   2643:   struct_value_incoming_rtx = STRUCT_VALUE_INCOMING;
                   2644: #else
                   2645: #ifdef STRUCT_VALUE_INCOMING_REGNUM
                   2646:   struct_value_incoming_rtx
                   2647:     = gen_rtx (REG, Pmode, STRUCT_VALUE_INCOMING_REGNUM);
                   2648: #else
                   2649:   struct_value_incoming_rtx = struct_value_rtx;
                   2650: #endif
                   2651: #endif
                   2652: 
                   2653: #ifdef STATIC_CHAIN_REGNUM
                   2654:   static_chain_rtx = gen_rtx (REG, Pmode, STATIC_CHAIN_REGNUM);
                   2655: 
                   2656: #ifdef STATIC_CHAIN_INCOMING_REGNUM
                   2657:   if (STATIC_CHAIN_INCOMING_REGNUM != STATIC_CHAIN_REGNUM)
                   2658:     static_chain_incoming_rtx = gen_rtx (REG, Pmode, STATIC_CHAIN_INCOMING_REGNUM);
                   2659:   else
                   2660: #endif
                   2661:     static_chain_incoming_rtx = static_chain_rtx;
                   2662: #endif
                   2663: 
                   2664: #ifdef STATIC_CHAIN
                   2665:   static_chain_rtx = STATIC_CHAIN;
                   2666: 
                   2667: #ifdef STATIC_CHAIN_INCOMING
                   2668:   static_chain_incoming_rtx = STATIC_CHAIN_INCOMING;
                   2669: #else
                   2670:   static_chain_incoming_rtx = static_chain_rtx;
                   2671: #endif
                   2672: #endif
                   2673: 
                   2674: #ifdef PIC_OFFSET_TABLE_REGNUM
                   2675:   pic_offset_table_rtx = gen_rtx (REG, Pmode, PIC_OFFSET_TABLE_REGNUM);
                   2676: #endif
                   2677: }

unix.superglobalmegacorp.com

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.