Annotation of GNUtools/cc/expmed.c.next, revision 1.1

1.1     ! root        1: /* Medium-level subroutines: convert bit-field store and extract
        !             2:    and shifts, multiplies and divides to rtl instructions.
        !             3:    Copyright (C) 1987, 1988, 1989, 1992, 1993 Free Software Foundation, Inc.
        !             4: 
        !             5: This file is part of GNU CC.
        !             6: 
        !             7: GNU CC is free software; you can redistribute it and/or modify
        !             8: it under the terms of the GNU General Public License as published by
        !             9: the Free Software Foundation; either version 2, or (at your option)
        !            10: any later version.
        !            11: 
        !            12: GNU CC is distributed in the hope that it will be useful,
        !            13: but WITHOUT ANY WARRANTY; without even the implied warranty of
        !            14: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
        !            15: GNU General Public License for more details.
        !            16: 
        !            17: You should have received a copy of the GNU General Public License
        !            18: along with GNU CC; see the file COPYING.  If not, write to
        !            19: the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
        !            20: 
        !            21: 
        !            22: #include "config.h"
        !            23: #include "rtl.h"
        !            24: #include "tree.h"
        !            25: #include "flags.h"
        !            26: #include "insn-flags.h"
        !            27: #include "insn-codes.h"
        !            28: #include "insn-config.h"
        !            29: #include "expr.h"
        !            30: #include "real.h"
        !            31: #include "recog.h"
        !            32: 
        !            33: static rtx extract_split_bit_field ();
        !            34: static rtx extract_fixed_bit_field ();
        !            35: static void store_split_bit_field ();
        !            36: static void store_fixed_bit_field ();
        !            37: static rtx mask_rtx ();
        !            38: static rtx lshift_value ();
        !            39: 
        !            40: #define CEIL(x,y) (((x) + (y) - 1) / (y))
        !            41: 
        !            42: /* Non-zero means divides or modulus operations are relatively cheap for
        !            43:    powers of two, so don't use branches; emit the operation instead. 
        !            44:    Usually, this will mean that the MD file will emit non-branch
        !            45:    sequences.  */
        !            46: 
        !            47: static int sdiv_pow2_cheap, smod_pow2_cheap;
        !            48: 
        !            49: #ifndef SLOW_UNALIGNED_ACCESS
        !            50: #define SLOW_UNALIGNED_ACCESS STRICT_ALIGNMENT
        !            51: #endif
        !            52: 
        !            53: /* For compilers that support multiple targets with different word sizes,
        !            54:    MAX_BITS_PER_WORD contains the biggest value of BITS_PER_WORD.  An example
        !            55:    is the H8/300(H) compiler.  */
        !            56: 
        !            57: #ifndef MAX_BITS_PER_WORD
        !            58: #define MAX_BITS_PER_WORD BITS_PER_WORD
        !            59: #endif
        !            60: 
        !            61: /* Cost of various pieces of RTL.  */
        !            62: static int add_cost, negate_cost, zero_cost;
        !            63: static int shift_cost[MAX_BITS_PER_WORD];
        !            64: static int shiftadd_cost[MAX_BITS_PER_WORD];
        !            65: static int shiftsub_cost[MAX_BITS_PER_WORD];
        !            66: 
        !            67: void
        !            68: init_expmed ()
        !            69: {
        !            70:   char *free_point;
        !            71:   /* This is "some random pseudo register" for purposes of calling recog
        !            72:      to see what insns exist.  */
        !            73:   rtx reg = gen_rtx (REG, word_mode, 10000);
        !            74:   rtx shift_insn, shiftadd_insn, shiftsub_insn;
        !            75:   int dummy;
        !            76:   int m;
        !            77: 
        !            78:   start_sequence ();
        !            79: 
        !            80:   /* Since we are on the permanent obstack, we must be sure we save this
        !            81:      spot AFTER we call start_sequence, since it will reuse the rtl it
        !            82:      makes.  */
        !            83: 
        !            84:   free_point = (char *) oballoc (0);
        !            85: 
        !            86:   zero_cost = rtx_cost (const0_rtx, 0);
        !            87:   add_cost = rtx_cost (gen_rtx (PLUS, word_mode, reg, reg), SET);
        !            88: 
        !            89:   shift_insn = emit_insn (gen_rtx (SET, VOIDmode, reg,
        !            90:                                   gen_rtx (ASHIFT, word_mode, reg,
        !            91:                                            const0_rtx)));
        !            92: 
        !            93:   shiftadd_insn = emit_insn (gen_rtx (SET, VOIDmode, reg,
        !            94:                                      gen_rtx (PLUS, word_mode,
        !            95:                                               gen_rtx (MULT, word_mode,
        !            96:                                                        reg, const0_rtx),
        !            97:                                               reg)));
        !            98: 
        !            99:   shiftsub_insn = emit_insn (gen_rtx (SET, VOIDmode, reg,
        !           100:                                      gen_rtx (MINUS, word_mode,
        !           101:                                               gen_rtx (MULT, word_mode,
        !           102:                                                         reg, const0_rtx),
        !           103:                                                reg)));
        !           104: 
        !           105:   init_recog ();
        !           106: 
        !           107:   shift_cost[0] = 0;
        !           108:   shiftadd_cost[0] = shiftsub_cost[0] = add_cost;
        !           109: 
        !           110:   for (m = 1; m < BITS_PER_WORD; m++)
        !           111:     {
        !           112:       shift_cost[m] = shiftadd_cost[m] = shiftsub_cost[m] = 32000;
        !           113: 
        !           114:       XEXP (SET_SRC (PATTERN (shift_insn)), 1) = GEN_INT (m);
        !           115:       if (recog (PATTERN (shift_insn), shift_insn, &dummy) >= 0)
        !           116:        shift_cost[m] = rtx_cost (SET_SRC (PATTERN (shift_insn)), SET);
        !           117: 
        !           118:       XEXP (XEXP (SET_SRC (PATTERN (shiftadd_insn)), 0), 1)
        !           119:        = GEN_INT ((HOST_WIDE_INT) 1 << m);
        !           120:       if (recog (PATTERN (shiftadd_insn), shiftadd_insn, &dummy) >= 0)
        !           121:        shiftadd_cost[m] = rtx_cost (SET_SRC (PATTERN (shiftadd_insn)), SET);
        !           122: 
        !           123:       XEXP (XEXP (SET_SRC (PATTERN (shiftsub_insn)), 0), 1)
        !           124:        = GEN_INT ((HOST_WIDE_INT) 1 << m);
        !           125:       if (recog (PATTERN (shiftsub_insn), shiftsub_insn, &dummy) >= 0)
        !           126:        shiftsub_cost[m] = rtx_cost (SET_SRC (PATTERN (shiftsub_insn)), SET);
        !           127:     }
        !           128: 
        !           129:   negate_cost = rtx_cost (gen_rtx (NEG, word_mode, reg), SET);
        !           130: 
        !           131:   sdiv_pow2_cheap
        !           132:     = (rtx_cost (gen_rtx (DIV, word_mode, reg, GEN_INT (32)), SET)
        !           133:        <= 2 * add_cost);
        !           134:   smod_pow2_cheap
        !           135:     = (rtx_cost (gen_rtx (MOD, word_mode, reg, GEN_INT (32)), SET)
        !           136:        <= 2 * add_cost);
        !           137: 
        !           138:   /* Free the objects we just allocated.  */
        !           139:   end_sequence ();
        !           140:   obfree (free_point);
        !           141: }
        !           142: 
        !           143: /* Return an rtx representing minus the value of X.
        !           144:    MODE is the intended mode of the result,
        !           145:    useful if X is a CONST_INT.  */
        !           146: 
        !           147: rtx
        !           148: negate_rtx (mode, x)
        !           149:      enum machine_mode mode;
        !           150:      rtx x;
        !           151: {
        !           152:   if (GET_CODE (x) == CONST_INT)
        !           153:     {
        !           154:       HOST_WIDE_INT val = - INTVAL (x);
        !           155:       if (GET_MODE_BITSIZE (mode) < HOST_BITS_PER_WIDE_INT)
        !           156:        {
        !           157:          /* Sign extend the value from the bits that are significant.  */
        !           158:          if (val & ((HOST_WIDE_INT) 1 << (GET_MODE_BITSIZE (mode) - 1)))
        !           159:            val |= (HOST_WIDE_INT) (-1) << GET_MODE_BITSIZE (mode);
        !           160:          else
        !           161:            val &= ((HOST_WIDE_INT) 1 << GET_MODE_BITSIZE (mode)) - 1;
        !           162:        }
        !           163:       return GEN_INT (val);
        !           164:     }
        !           165:   else
        !           166:     return expand_unop (GET_MODE (x), neg_optab, x, NULL_RTX, 0);
        !           167: }
        !           168: 
        !           169: /* Generate code to store value from rtx VALUE
        !           170:    into a bit-field within structure STR_RTX
        !           171:    containing BITSIZE bits starting at bit BITNUM.
        !           172:    FIELDMODE is the machine-mode of the FIELD_DECL node for this field.
        !           173:    ALIGN is the alignment that STR_RTX is known to have, measured in bytes.
        !           174:    TOTAL_SIZE is the size of the structure in bytes, or -1 if varying.  */
        !           175: 
        !           176: /* ??? Note that there are two different ideas here for how
        !           177:    to determine the size to count bits within, for a register.
        !           178:    One is BITS_PER_WORD, and the other is the size of operand 3
        !           179:    of the insv pattern.  (The latter assumes that an n-bit machine
        !           180:    will be able to insert bit fields up to n bits wide.)
        !           181:    It isn't certain that either of these is right.
        !           182:    extract_bit_field has the same quandary.  */
        !           183: 
        !           184: rtx
        !           185: store_bit_field (str_rtx, bitsize, bitnum, fieldmode, value, align, total_size)
        !           186:      rtx str_rtx;
        !           187:      register int bitsize;
        !           188:      int bitnum;
        !           189:      enum machine_mode fieldmode;
        !           190:      rtx value;
        !           191:      int align;
        !           192:      int total_size;
        !           193: {
        !           194:   int unit = (GET_CODE (str_rtx) == MEM) ? BITS_PER_UNIT : BITS_PER_WORD;
        !           195:   register int offset = bitnum / unit;
        !           196:   register int bitpos = bitnum % unit;
        !           197:   register rtx op0 = str_rtx;
        !           198: 
        !           199:   if (GET_CODE (str_rtx) == MEM && ! MEM_IN_STRUCT_P (str_rtx))
        !           200:     abort ();
        !           201: 
        !           202:   /* Discount the part of the structure before the desired byte.
        !           203:      We need to know how many bytes are safe to reference after it.  */
        !           204:   if (total_size >= 0)
        !           205:     total_size -= (bitpos / BIGGEST_ALIGNMENT
        !           206:                   * (BIGGEST_ALIGNMENT / BITS_PER_UNIT));
        !           207: 
        !           208:   while (GET_CODE (op0) == SUBREG)
        !           209:     {
        !           210:       /* The following line once was done only if WORDS_BIG_ENDIAN,
        !           211:         but I think that is a mistake.  WORDS_BIG_ENDIAN is
        !           212:         meaningful at a much higher level; when structures are copied
        !           213:         between memory and regs, the higher-numbered regs
        !           214:         always get higher addresses.  */
        !           215:       offset += SUBREG_WORD (op0);
        !           216:       /* We used to adjust BITPOS here, but now we do the whole adjustment
        !           217:         right after the loop.  */
        !           218:       op0 = SUBREG_REG (op0);
        !           219:     }
        !           220: 
        !           221: #if BYTES_BIG_ENDIAN
        !           222:   /* If OP0 is a register, BITPOS must count within a word.
        !           223:      But as we have it, it counts within whatever size OP0 now has.
        !           224:      On a bigendian machine, these are not the same, so convert.  */
        !           225:   if (GET_CODE (op0) != MEM && unit > GET_MODE_BITSIZE (GET_MODE (op0)))
        !           226:     bitpos += unit - GET_MODE_BITSIZE (GET_MODE (op0));
        !           227: #endif
        !           228: 
        !           229:   value = protect_from_queue (value, 0);
        !           230: 
        !           231:   if (flag_force_mem)
        !           232:     value = force_not_mem (value);
        !           233: 
        !           234:   /* Note that the adjustment of BITPOS above has no effect on whether
        !           235:      BITPOS is 0 in a REG bigger than a word.  */
        !           236:   if (GET_MODE_SIZE (fieldmode) >= UNITS_PER_WORD
        !           237:       && (GET_CODE (op0) != MEM
        !           238:          || ! SLOW_UNALIGNED_ACCESS
        !           239:          || (offset * BITS_PER_UNIT % bitsize == 0
        !           240:              && align % GET_MODE_SIZE (fieldmode) == 0))
        !           241:       && bitpos == 0 && bitsize == GET_MODE_BITSIZE (fieldmode))
        !           242:     {
        !           243:       /* Storing in a full-word or multi-word field in a register
        !           244:         can be done with just SUBREG.  */
        !           245:       if (GET_MODE (op0) != fieldmode)
        !           246:        {
        !           247:          if (GET_CODE (op0) == REG)
        !           248:            op0 = gen_rtx (SUBREG, fieldmode, op0, offset);
        !           249:          else
        !           250:            op0 = change_address (op0, fieldmode,
        !           251:                                  plus_constant (XEXP (op0, 0), offset));
        !           252:        }
        !           253:       emit_move_insn (op0, value);
        !           254:       return value;
        !           255:     }
        !           256: 
        !           257:   /* Storing an lsb-aligned field in a register
        !           258:      can be done with a movestrict instruction.  */
        !           259: 
        !           260:   if (GET_CODE (op0) != MEM
        !           261: #if BYTES_BIG_ENDIAN
        !           262:       && bitpos + bitsize == unit
        !           263: #else
        !           264:       && bitpos == 0
        !           265: #endif
        !           266:       && bitsize == GET_MODE_BITSIZE (fieldmode)
        !           267:       && (GET_MODE (op0) == fieldmode
        !           268:          || (movstrict_optab->handlers[(int) fieldmode].insn_code
        !           269:              != CODE_FOR_nothing)))
        !           270:     {
        !           271:       /* Get appropriate low part of the value being stored.  */
        !           272:       if (GET_CODE (value) == CONST_INT || GET_CODE (value) == REG)
        !           273:        value = gen_lowpart (fieldmode, value);
        !           274:       else if (!(GET_CODE (value) == SYMBOL_REF
        !           275:                 || GET_CODE (value) == LABEL_REF
        !           276:                 || GET_CODE (value) == CONST))
        !           277:        value = convert_to_mode (fieldmode, value, 0);
        !           278: 
        !           279:       if (GET_MODE (op0) == fieldmode)
        !           280:        emit_move_insn (op0, value);
        !           281:       else
        !           282:        {
        !           283:          int icode = movstrict_optab->handlers[(int) fieldmode].insn_code;
        !           284:          if(! (*insn_operand_predicate[icode][1]) (value, fieldmode))
        !           285:            value = copy_to_mode_reg (fieldmode, value);
        !           286:          emit_insn (GEN_FCN (icode)
        !           287:                   (gen_rtx (SUBREG, fieldmode, op0, offset), value));
        !           288:        }
        !           289:       return value;
        !           290:     }
        !           291: 
        !           292:   /* Handle fields bigger than a word.  */
        !           293: 
        !           294:   if (bitsize > BITS_PER_WORD)
        !           295:     {
        !           296:       /* Here we transfer the words of the field
        !           297:         in the order least significant first.
        !           298:         This is because the most significant word is the one which may
        !           299:         be less than full.  */
        !           300: 
        !           301:       int nwords = (bitsize + (BITS_PER_WORD - 1)) / BITS_PER_WORD;
        !           302:       int i;
        !           303: 
        !           304:       /* This is the mode we must force value to, so that there will be enough
        !           305:         subwords to extract.  Note that fieldmode will often (always?) be
        !           306:         VOIDmode, because that is what store_field uses to indicate that this
        !           307:         is a bit field, but passing VOIDmode to operand_subword_force will
        !           308:         result in an abort.  */
        !           309:       fieldmode = mode_for_size (nwords * BITS_PER_WORD, MODE_INT, 0);
        !           310: 
        !           311:       for (i = 0; i < nwords; i++)
        !           312:        {
        !           313:          /* If I is 0, use the low-order word in both field and target;
        !           314:             if I is 1, use the next to lowest word; and so on.  */
        !           315:          int wordnum = (WORDS_BIG_ENDIAN ? nwords - i - 1 : i);
        !           316:          int bit_offset = (WORDS_BIG_ENDIAN
        !           317:                            ? MAX (bitsize - (i + 1) * BITS_PER_WORD, 0)
        !           318:                            : i * BITS_PER_WORD);
        !           319:          store_bit_field (op0, MIN (BITS_PER_WORD,
        !           320:                                     bitsize - i * BITS_PER_WORD),
        !           321:                           bitnum + bit_offset, word_mode,
        !           322:                           operand_subword_force (value, wordnum,
        !           323:                                                  (GET_MODE (value) == VOIDmode
        !           324:                                                   ? fieldmode
        !           325:                                                   : GET_MODE (value))),
        !           326:                           align, total_size);
        !           327:        }
        !           328:       return value;
        !           329:     }
        !           330: 
        !           331:   /* From here on we can assume that the field to be stored in is
        !           332:      a full-word (whatever type that is), since it is shorter than a word.  */
        !           333: 
        !           334:   /* OFFSET is the number of words or bytes (UNIT says which)
        !           335:      from STR_RTX to the first word or byte containing part of the field.  */
        !           336: 
        !           337:   if (GET_CODE (op0) == REG)
        !           338:     {
        !           339:       if (offset != 0
        !           340:          || GET_MODE_SIZE (GET_MODE (op0)) > UNITS_PER_WORD)
        !           341:        op0 = gen_rtx (SUBREG, TYPE_MODE (type_for_size (BITS_PER_WORD, 0)),
        !           342:                       op0, offset);
        !           343:       offset = 0;
        !           344:     }
        !           345:   else
        !           346:     {
        !           347:       op0 = protect_from_queue (op0, 1);
        !           348:     }
        !           349: 
        !           350:   /* Now OFFSET is nonzero only if OP0 is memory
        !           351:      and is therefore always measured in bytes.  */
        !           352: 
        !           353: #ifdef HAVE_insv
        !           354:   if (HAVE_insv
        !           355:       && !(bitsize == 1 && GET_CODE (value) == CONST_INT)
        !           356:       /* Ensure insv's size is wide enough for this field.  */
        !           357:       && (GET_MODE_BITSIZE (insn_operand_mode[(int) CODE_FOR_insv][3])
        !           358:          >= bitsize))
        !           359:     {
        !           360:       int xbitpos = bitpos;
        !           361:       rtx value1;
        !           362:       rtx xop0 = op0;
        !           363:       rtx last = get_last_insn ();
        !           364:       rtx pat;
        !           365:       enum machine_mode maxmode
        !           366:        = insn_operand_mode[(int) CODE_FOR_insv][3];
        !           367: 
        !           368:       int save_volatile_ok = volatile_ok;
        !           369:       volatile_ok = 1;
        !           370: 
        !           371:       /* If this machine's insv can only insert into a register, or if we
        !           372:         are to force MEMs into a register, copy OP0 into a register and
        !           373:         save it back later.  */
        !           374:       if (GET_CODE (op0) == MEM
        !           375:          && (flag_force_mem
        !           376:              || ! ((*insn_operand_predicate[(int) CODE_FOR_insv][0])
        !           377:                    (op0, VOIDmode))))
        !           378:        {
        !           379:          rtx tempreg;
        !           380:          enum machine_mode bestmode;
        !           381: 
        !           382:          /* Get the mode to use for inserting into this field.  If OP0 is
        !           383:             BLKmode, get the smallest mode consistent with the alignment. If
        !           384:             OP0 is a non-BLKmode object that is no wider than MAXMODE, use its
        !           385:             mode. Otherwise, use the smallest mode containing the field.  */
        !           386: 
        !           387:          if (GET_MODE (op0) == BLKmode
        !           388:              || GET_MODE_SIZE (GET_MODE (op0)) > GET_MODE_SIZE (maxmode))
        !           389:            bestmode
        !           390:              = get_best_mode (bitsize, bitnum, align * BITS_PER_UNIT, maxmode,
        !           391:                               MEM_VOLATILE_P (op0));
        !           392:          else
        !           393:            bestmode = GET_MODE (op0);
        !           394: 
        !           395:          if (bestmode == VOIDmode
        !           396:              || (STRICT_ALIGNMENT && GET_MODE_SIZE (bestmode) > align))
        !           397:            goto insv_loses;
        !           398: 
        !           399:          /* Adjust address to point to the containing unit of that mode.  */
        !           400:          unit = GET_MODE_BITSIZE (bestmode);
        !           401:          /* Compute offset as multiple of this unit, counting in bytes.  */
        !           402:          offset = (bitnum / unit) * GET_MODE_SIZE (bestmode);
        !           403:          bitpos = bitnum % unit;
        !           404:          op0 = change_address (op0, bestmode, 
        !           405:                                plus_constant (XEXP (op0, 0), offset));
        !           406: 
        !           407:          /* Fetch that unit, store the bitfield in it, then store the unit.  */
        !           408:          tempreg = copy_to_reg (op0);
        !           409:          store_bit_field (tempreg, bitsize, bitpos, fieldmode, value,
        !           410:                           align, total_size);
        !           411:          emit_move_insn (op0, tempreg);
        !           412:          return value;
        !           413:        }
        !           414:       volatile_ok = save_volatile_ok;
        !           415: 
        !           416:       /* Add OFFSET into OP0's address.  */
        !           417:       if (GET_CODE (xop0) == MEM)
        !           418:        xop0 = change_address (xop0, byte_mode,
        !           419:                               plus_constant (XEXP (xop0, 0), offset));
        !           420: 
        !           421:       /* If xop0 is a register, we need it in MAXMODE
        !           422:         to make it acceptable to the format of insv.  */
        !           423:       if (GET_CODE (xop0) == SUBREG)
        !           424:        PUT_MODE (xop0, maxmode);
        !           425:       if (GET_CODE (xop0) == REG && GET_MODE (xop0) != maxmode)
        !           426:        xop0 = gen_rtx (SUBREG, maxmode, xop0, 0);
        !           427: 
        !           428:       /* On big-endian machines, we count bits from the most significant.
        !           429:         If the bit field insn does not, we must invert.  */
        !           430: 
        !           431: #if BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN
        !           432:       xbitpos = unit - bitsize - xbitpos;
        !           433: #endif
        !           434:       /* We have been counting XBITPOS within UNIT.
        !           435:         Count instead within the size of the register.  */
        !           436: #if BITS_BIG_ENDIAN
        !           437:       if (GET_CODE (xop0) != MEM)
        !           438:        xbitpos += GET_MODE_BITSIZE (maxmode) - unit;
        !           439: #endif
        !           440:       unit = GET_MODE_BITSIZE (maxmode);
        !           441: 
        !           442:       /* Convert VALUE to maxmode (which insv insn wants) in VALUE1.  */
        !           443:       value1 = value;
        !           444:       if (GET_MODE (value) != maxmode)
        !           445:        {
        !           446:          if (GET_MODE_BITSIZE (GET_MODE (value)) >= bitsize)
        !           447:            {
        !           448:              /* Optimization: Don't bother really extending VALUE
        !           449:                 if it has all the bits we will actually use.  However,
        !           450:                 if we must narrow it, be sure we do it correctly.  */
        !           451: 
        !           452:              if (GET_MODE_SIZE (GET_MODE (value)) < GET_MODE_SIZE (maxmode))
        !           453:                {
        !           454:                  /* Avoid making subreg of a subreg, or of a mem.  */
        !           455:                  if (GET_CODE (value1) != REG)
        !           456:                value1 = copy_to_reg (value1);
        !           457:                  value1 = gen_rtx (SUBREG, maxmode, value1, 0);
        !           458:                }
        !           459:              else
        !           460:                value1 = gen_lowpart (maxmode, value1);
        !           461:            }
        !           462:          else if (!CONSTANT_P (value))
        !           463:            /* Parse phase is supposed to make VALUE's data type
        !           464:               match that of the component reference, which is a type
        !           465:               at least as wide as the field; so VALUE should have
        !           466:               a mode that corresponds to that type.  */
        !           467:            abort ();
        !           468:        }
        !           469: 
        !           470:       /* If this machine's insv insists on a register,
        !           471:         get VALUE1 into a register.  */
        !           472:       if (! ((*insn_operand_predicate[(int) CODE_FOR_insv][3])
        !           473:             (value1, maxmode)))
        !           474:        value1 = force_reg (maxmode, value1);
        !           475: 
        !           476:       pat = gen_insv (xop0, GEN_INT (bitsize), GEN_INT (xbitpos), value1);
        !           477:       if (pat)
        !           478:        emit_insn (pat);
        !           479:       else
        !           480:         {
        !           481:          delete_insns_since (last);
        !           482:          store_fixed_bit_field (op0, offset, bitsize, bitpos, value, align);
        !           483:        }
        !           484:     }
        !           485:   else
        !           486:     insv_loses:
        !           487: #endif
        !           488:     /* Insv is not available; store using shifts and boolean ops.  */
        !           489:     store_fixed_bit_field (op0, offset, bitsize, bitpos, value, align);
        !           490:   return value;
        !           491: }
        !           492: 
        !           493: /* Use shifts and boolean operations to store VALUE
        !           494:    into a bit field of width BITSIZE
        !           495:    in a memory location specified by OP0 except offset by OFFSET bytes.
        !           496:      (OFFSET must be 0 if OP0 is a register.)
        !           497:    The field starts at position BITPOS within the byte.
        !           498:     (If OP0 is a register, it may be a full word or a narrower mode,
        !           499:      but BITPOS still counts within a full word,
        !           500:      which is significant on bigendian machines.)
        !           501:    STRUCT_ALIGN is the alignment the structure is known to have (in bytes).
        !           502: 
        !           503:    Note that protect_from_queue has already been done on OP0 and VALUE.  */
        !           504: 
        !           505: static void
        !           506: store_fixed_bit_field (op0, offset, bitsize, bitpos, value, struct_align)
        !           507:      register rtx op0;
        !           508:      register int offset, bitsize, bitpos;
        !           509:      register rtx value;
        !           510:      int struct_align;
        !           511: {
        !           512:   register enum machine_mode mode;
        !           513:   int total_bits = BITS_PER_WORD;
        !           514:   rtx subtarget, temp;
        !           515:   int all_zero = 0;
        !           516:   int all_one = 0;
        !           517: 
        !           518:   /* There is a case not handled here:
        !           519:      a structure with a known alignment of just a halfword
        !           520:      and a field split across two aligned halfwords within the structure.
        !           521:      Or likewise a structure with a known alignment of just a byte
        !           522:      and a field split across two bytes.
        !           523:      Such cases are not supposed to be able to occur.  */
        !           524: 
        !           525:   if (GET_CODE (op0) == REG || GET_CODE (op0) == SUBREG)
        !           526:     {
        !           527:       if (offset != 0)
        !           528:        abort ();
        !           529:       /* Special treatment for a bit field split across two registers.  */
        !           530:       if (bitsize + bitpos > BITS_PER_WORD)
        !           531:        {
        !           532:          store_split_bit_field (op0, bitsize, bitpos,
        !           533:                                 value, BITS_PER_WORD);
        !           534:          return;
        !           535:        }
        !           536:     }
        !           537:   else
        !           538:     {
        !           539:       /* Get the proper mode to use for this field.  We want a mode that
        !           540:         includes the entire field.  If such a mode would be larger than
        !           541:         a word, we won't be doing the extraction the normal way.  */
        !           542: 
        !           543:       mode = get_best_mode (bitsize, bitpos + offset * BITS_PER_UNIT,
        !           544:                            struct_align * BITS_PER_UNIT, word_mode,
        !           545:                            GET_CODE (op0) == MEM && MEM_VOLATILE_P (op0));
        !           546: 
        !           547:       if (mode == VOIDmode)
        !           548:        {
        !           549:          /* The only way this should occur is if the field spans word
        !           550:             boundaries.  */
        !           551:          store_split_bit_field (op0,
        !           552:                                 bitsize, bitpos + offset * BITS_PER_UNIT,
        !           553:                                 value, struct_align);
        !           554:          return;
        !           555:        }
        !           556: 
        !           557:       total_bits = GET_MODE_BITSIZE (mode);
        !           558: 
        !           559:       /* Get ref to an aligned byte, halfword, or word containing the field.
        !           560:         Adjust BITPOS to be position within a word,
        !           561:         and OFFSET to be the offset of that word.
        !           562:         Then alter OP0 to refer to that word.  */
        !           563:       bitpos += (offset % (total_bits / BITS_PER_UNIT)) * BITS_PER_UNIT;
        !           564:       offset -= (offset % (total_bits / BITS_PER_UNIT));
        !           565:       op0 = change_address (op0, mode,
        !           566:                            plus_constant (XEXP (op0, 0), offset));
        !           567:     }
        !           568: 
        !           569:   mode = GET_MODE (op0);
        !           570: 
        !           571:   /* Now MODE is either some integral mode for a MEM as OP0,
        !           572:      or is a full-word for a REG as OP0.  TOTAL_BITS corresponds.
        !           573:      The bit field is contained entirely within OP0.
        !           574:      BITPOS is the starting bit number within OP0.
        !           575:      (OP0's mode may actually be narrower than MODE.)  */
        !           576: 
        !           577: #if BYTES_BIG_ENDIAN
        !           578:   /* BITPOS is the distance between our msb
        !           579:      and that of the containing datum.
        !           580:      Convert it to the distance from the lsb.  */
        !           581: 
        !           582:   bitpos = total_bits - bitsize - bitpos;
        !           583: #endif
        !           584:   /* Now BITPOS is always the distance between our lsb
        !           585:      and that of OP0.  */
        !           586: 
        !           587:   /* Shift VALUE left by BITPOS bits.  If VALUE is not constant,
        !           588:      we must first convert its mode to MODE.  */
        !           589: 
        !           590:   if (GET_CODE (value) == CONST_INT)
        !           591:     {
        !           592:       register HOST_WIDE_INT v = INTVAL (value);
        !           593: 
        !           594:       if (bitsize < HOST_BITS_PER_WIDE_INT)
        !           595:        v &= ((HOST_WIDE_INT) 1 << bitsize) - 1;
        !           596: 
        !           597:       if (v == 0)
        !           598:        all_zero = 1;
        !           599:       else if ((bitsize < HOST_BITS_PER_WIDE_INT
        !           600:                && v == ((HOST_WIDE_INT) 1 << bitsize) - 1)
        !           601:               || (bitsize == HOST_BITS_PER_WIDE_INT && v == -1))
        !           602:        all_one = 1;
        !           603: 
        !           604:       value = lshift_value (mode, value, bitpos, bitsize);
        !           605:     }
        !           606:   else
        !           607:     {
        !           608:       int must_and = (GET_MODE_BITSIZE (GET_MODE (value)) != bitsize
        !           609:                      && bitpos + bitsize != GET_MODE_BITSIZE (mode));
        !           610: 
        !           611:       if (GET_MODE (value) != mode)
        !           612:        {
        !           613:          /* If VALUE is a floating-point mode, access it as an integer
        !           614:             of the corresponding size, then convert it.  This can occur on
        !           615:             a machine with 64 bit registers that uses SFmode for float.  */
        !           616:          if (GET_MODE_CLASS (GET_MODE (value)) == MODE_FLOAT)
        !           617:            {
        !           618:              if (GET_CODE (value) != REG)
        !           619:                value = copy_to_reg (value);
        !           620:              value
        !           621:                = gen_rtx (SUBREG, word_mode, value, 0);
        !           622:            }
        !           623: 
        !           624:          if ((GET_CODE (value) == REG || GET_CODE (value) == SUBREG)
        !           625:              && GET_MODE_SIZE (mode) < GET_MODE_SIZE (GET_MODE (value)))
        !           626:            value = gen_lowpart (mode, value);
        !           627:          else
        !           628:            value = convert_to_mode (mode, value, 1);
        !           629:        }
        !           630: 
        !           631:       if (must_and)
        !           632:        value = expand_binop (mode, and_optab, value,
        !           633:                              mask_rtx (mode, 0, bitsize, 0),
        !           634:                              NULL_RTX, 1, OPTAB_LIB_WIDEN);
        !           635:       if (bitpos > 0)
        !           636:        value = expand_shift (LSHIFT_EXPR, mode, value,
        !           637:                              build_int_2 (bitpos, 0), NULL_RTX, 1);
        !           638:     }
        !           639: 
        !           640:   /* Now clear the chosen bits in OP0,
        !           641:      except that if VALUE is -1 we need not bother.  */
        !           642: 
        !           643:   subtarget = (GET_CODE (op0) == REG || ! flag_force_mem) ? op0 : 0;
        !           644: 
        !           645:   if (! all_one)
        !           646:     {
        !           647:       temp = expand_binop (mode, and_optab, op0,
        !           648:                           mask_rtx (mode, bitpos, bitsize, 1),
        !           649:                           subtarget, 1, OPTAB_LIB_WIDEN);
        !           650:       subtarget = temp;
        !           651:     }
        !           652:   else
        !           653:     temp = op0;
        !           654: 
        !           655:   /* Now logical-or VALUE into OP0, unless it is zero.  */
        !           656: 
        !           657:   if (! all_zero)
        !           658:     temp = expand_binop (mode, ior_optab, temp, value,
        !           659:                         subtarget, 1, OPTAB_LIB_WIDEN);
        !           660:   if (op0 != temp)
        !           661:     emit_move_insn (op0, temp);
        !           662: }
        !           663: 
        !           664: /* Store a bit field that is split across multiple accessible memory objects.
        !           665: 
        !           666:    OP0 is the REG, SUBREG or MEM rtx for the first of the objects.
        !           667:    BITSIZE is the field width; BITPOS the position of its first bit
        !           668:    (within the word).
        !           669:    VALUE is the value to store.
        !           670:    ALIGN is the known alignment of OP0, measured in bytes.
        !           671:    This is also the size of the memory objects to be used.
        !           672: 
        !           673:    This does not yet handle fields wider than BITS_PER_WORD.  */
        !           674: 
        !           675: static void
        !           676: store_split_bit_field (op0, bitsize, bitpos, value, align)
        !           677:      rtx op0;
        !           678:      int bitsize, bitpos;
        !           679:      rtx value;
        !           680:      int align;
        !           681: {
        !           682:   /* Make sure UNIT isn't larger than BITS_PER_WORD, we can only handle that
        !           683:      much at a time.  */
        !           684:   int unit = MIN (align * BITS_PER_UNIT, BITS_PER_WORD);
        !           685:   int bitsdone = 0;
        !           686: 
        !           687:   /* If VALUE is a constant other than a CONST_INT, get it into a register in
        !           688:      WORD_MODE.  If we can do this using gen_lowpart_common, do so.  Note
        !           689:      that VALUE might be a floating-point constant.  */
        !           690:   if (CONSTANT_P (value) && GET_CODE (value) != CONST_INT)
        !           691:     {
        !           692:       rtx word = gen_lowpart_common (word_mode, value);
        !           693: 
        !           694:       if (word)
        !           695:        value = word;
        !           696:       else
        !           697:        value = gen_lowpart_common (word_mode,
        !           698:                                    force_reg (GET_MODE (value), value));
        !           699:     }
        !           700: 
        !           701:   while (bitsdone < bitsize)
        !           702:     {
        !           703:       int thissize;
        !           704:       rtx part, word;
        !           705:       int thispos;
        !           706:       int offset;
        !           707: 
        !           708:       offset = (bitpos + bitsdone) / unit;
        !           709:       thispos = (bitpos + bitsdone) % unit;
        !           710: 
        !           711:       /* THISSIZE must not overrun a word boundary.  Otherwise,
        !           712:         store_fixed_bit_field will call us again, and we will mutually
        !           713:         recurse forever.  */
        !           714:       thissize = MIN (bitsize - bitsdone, BITS_PER_WORD);
        !           715:       thissize = MIN (thissize, unit - thispos);
        !           716: 
        !           717: #if BYTES_BIG_ENDIAN
        !           718:       /* Fetch successively less significant portions.  */
        !           719:       if (GET_CODE (value) == CONST_INT)
        !           720:        part = GEN_INT (((unsigned HOST_WIDE_INT) (INTVAL (value))
        !           721:                         >> (bitsize - bitsdone - thissize))
        !           722:                        & (((HOST_WIDE_INT) 1 << thissize) - 1));
        !           723:       else
        !           724:        /* The args are chosen so that the last part
        !           725:           includes the lsb.  */
        !           726:        part = extract_fixed_bit_field (word_mode, value, 0, thissize,
        !           727:                                        BITS_PER_WORD - bitsize + bitsdone,
        !           728:                                        NULL_RTX, 1, align);
        !           729: #else
        !           730:       /* Fetch successively more significant portions.  */
        !           731:       if (GET_CODE (value) == CONST_INT)
        !           732:        part = GEN_INT (((unsigned HOST_WIDE_INT) (INTVAL (value)) >> bitsdone)
        !           733:                        & (((HOST_WIDE_INT) 1 << thissize) - 1));
        !           734:       else
        !           735:        part = extract_fixed_bit_field (word_mode, value, 0, thissize,
        !           736:                                        bitsdone, NULL_RTX, 1, align);
        !           737: #endif
        !           738: 
        !           739:       /* If OP0 is a register, then handle OFFSET here.
        !           740:         In the register case, UNIT must be a whole word.  */
        !           741:       if (GET_CODE (op0) == SUBREG || GET_CODE (op0) == REG)
        !           742:        {
        !           743:          word = operand_subword (op0, offset, 1, GET_MODE (op0));
        !           744:          offset = 0;
        !           745:        }
        !           746:       else
        !           747:        word = op0;
        !           748: 
        !           749:       if (word == 0)
        !           750:        abort ();
        !           751: 
        !           752:       /* OFFSET is in UNITs, and UNIT is in bits.
        !           753:          store_fixed_bit_field wants offset in bytes.  */
        !           754:       store_fixed_bit_field (word, offset * unit / BITS_PER_UNIT,
        !           755:                             thissize, thispos, part, align);
        !           756:       bitsdone += thissize;
        !           757:     }
        !           758: }
        !           759: 
        !           760: /* Generate code to extract a byte-field from STR_RTX
        !           761:    containing BITSIZE bits, starting at BITNUM,
        !           762:    and put it in TARGET if possible (if TARGET is nonzero).
        !           763:    Regardless of TARGET, we return the rtx for where the value is placed.
        !           764:    It may be a QUEUED.
        !           765: 
        !           766:    STR_RTX is the structure containing the byte (a REG or MEM).
        !           767:    UNSIGNEDP is nonzero if this is an unsigned bit field.
        !           768:    MODE is the natural mode of the field value once extracted.
        !           769:    TMODE is the mode the caller would like the value to have;
        !           770:    but the value may be returned with type MODE instead.
        !           771: 
        !           772:    ALIGN is the alignment that STR_RTX is known to have, measured in bytes.
        !           773:    TOTAL_SIZE is the size in bytes of the containing structure,
        !           774:    or -1 if varying.
        !           775: 
        !           776:    If a TARGET is specified and we can store in it at no extra cost,
        !           777:    we do so, and return TARGET.
        !           778:    Otherwise, we return a REG of mode TMODE or MODE, with TMODE preferred
        !           779:    if they are equally easy.  */
        !           780: 
        !           781: rtx
        !           782: extract_bit_field (str_rtx, bitsize, bitnum, unsignedp,
        !           783:                   target, mode, tmode, align, total_size)
        !           784:      rtx str_rtx;
        !           785:      register int bitsize;
        !           786:      int bitnum;
        !           787:      int unsignedp;
        !           788:      rtx target;
        !           789:      enum machine_mode mode, tmode;
        !           790:      int align;
        !           791:      int total_size;
        !           792: {
        !           793:   int unit = (GET_CODE (str_rtx) == MEM) ? BITS_PER_UNIT : BITS_PER_WORD;
        !           794:   register int offset = bitnum / unit;
        !           795:   register int bitpos = bitnum % unit;
        !           796:   register rtx op0 = str_rtx;
        !           797:   rtx spec_target = target;
        !           798:   rtx spec_target_subreg = 0;
        !           799: 
        !           800:   if (GET_CODE (str_rtx) == MEM && ! MEM_IN_STRUCT_P (str_rtx))
        !           801:     abort ();
        !           802: 
        !           803:   /* Discount the part of the structure before the desired byte.
        !           804:      We need to know how many bytes are safe to reference after it.  */
        !           805:   if (total_size >= 0)
        !           806:     total_size -= (bitpos / BIGGEST_ALIGNMENT
        !           807:                   * (BIGGEST_ALIGNMENT / BITS_PER_UNIT));
        !           808: 
        !           809:   if (tmode == VOIDmode)
        !           810:     tmode = mode;
        !           811:   while (GET_CODE (op0) == SUBREG)
        !           812:     {
        !           813:       offset += SUBREG_WORD (op0);
        !           814:       op0 = SUBREG_REG (op0);
        !           815:     }
        !           816:   
        !           817: #if BYTES_BIG_ENDIAN
        !           818:   /* If OP0 is a register, BITPOS must count within a word.
        !           819:      But as we have it, it counts within whatever size OP0 now has.
        !           820:      On a bigendian machine, these are not the same, so convert.  */
        !           821:   if (GET_CODE (op0) != MEM && unit > GET_MODE_BITSIZE (GET_MODE (op0)))
        !           822:     bitpos += unit - GET_MODE_BITSIZE (GET_MODE (op0));
        !           823: #endif
        !           824: 
        !           825:   /* Extracting a full-word or multi-word value
        !           826:      from a structure in a register or aligned memory.
        !           827:      This can be done with just SUBREG.
        !           828:      So too extracting a subword value in
        !           829:      the least significant part of the register.  */
        !           830: 
        !           831:   if ((GET_CODE (op0) == REG
        !           832:        || (GET_CODE (op0) == MEM
        !           833:           && (! SLOW_UNALIGNED_ACCESS
        !           834:               || (offset * BITS_PER_UNIT % bitsize == 0
        !           835:                   && align * BITS_PER_UNIT % bitsize == 0))))
        !           836:       && ((bitsize >= BITS_PER_WORD && bitsize == GET_MODE_BITSIZE (mode)
        !           837:           && bitpos % BITS_PER_WORD == 0)
        !           838:          || (mode_for_size (bitsize, GET_MODE_CLASS (tmode), 0) != BLKmode
        !           839: #if BYTES_BIG_ENDIAN
        !           840:              && bitpos + bitsize == BITS_PER_WORD
        !           841: #else
        !           842:              && bitpos == 0
        !           843: #endif
        !           844:              )))
        !           845:     {
        !           846:       enum machine_mode mode1
        !           847:        = mode_for_size (bitsize, GET_MODE_CLASS (tmode), 0);
        !           848: 
        !           849:       if (mode1 != GET_MODE (op0))
        !           850:        {
        !           851:          if (GET_CODE (op0) == REG)
        !           852:            op0 = gen_rtx (SUBREG, mode1, op0, offset);
        !           853:          else
        !           854:            op0 = change_address (op0, mode1,
        !           855:                                  plus_constant (XEXP (op0, 0), offset));
        !           856:        }
        !           857:       if (mode1 != mode)
        !           858:        return convert_to_mode (tmode, op0, unsignedp);
        !           859:       return op0;
        !           860:     }
        !           861: 
        !           862:   /* Handle fields bigger than a word.  */
        !           863:   
        !           864:   if (bitsize > BITS_PER_WORD)
        !           865:     {
        !           866:       /* Here we transfer the words of the field
        !           867:         in the order least significant first.
        !           868:         This is because the most significant word is the one which may
        !           869:         be less than full.  */
        !           870: 
        !           871:       int nwords = (bitsize + (BITS_PER_WORD - 1)) / BITS_PER_WORD;
        !           872:       int i;
        !           873: 
        !           874:       if (target == 0 || GET_CODE (target) != REG)
        !           875:        target = gen_reg_rtx (mode);
        !           876: 
        !           877:       for (i = 0; i < nwords; i++)
        !           878:        {
        !           879:          /* If I is 0, use the low-order word in both field and target;
        !           880:             if I is 1, use the next to lowest word; and so on.  */
        !           881:          int wordnum = (WORDS_BIG_ENDIAN ? nwords - i - 1 : i);
        !           882:          int bit_offset = (WORDS_BIG_ENDIAN
        !           883:                            ? MAX (0, bitsize - (i + 1) * BITS_PER_WORD)
        !           884:                            : i * BITS_PER_WORD);
        !           885:          rtx target_part = operand_subword (target, wordnum, 1, VOIDmode);
        !           886:          rtx result_part
        !           887:            = extract_bit_field (op0, MIN (BITS_PER_WORD,
        !           888:                                           bitsize - i * BITS_PER_WORD),
        !           889:                                 bitnum + bit_offset,
        !           890:                                 1, target_part, mode, word_mode,
        !           891:                                 align, total_size);
        !           892: 
        !           893:          if (target_part == 0)
        !           894:            abort ();
        !           895: 
        !           896:          if (result_part != target_part)
        !           897:            emit_move_insn (target_part, result_part);
        !           898:        }
        !           899: 
        !           900:       return target;
        !           901:     }
        !           902:   
        !           903:   /* From here on we know the desired field is smaller than a word
        !           904:      so we can assume it is an integer.  So we can safely extract it as one
        !           905:      size of integer, if necessary, and then truncate or extend
        !           906:      to the size that is wanted.  */
        !           907: 
        !           908:   /* OFFSET is the number of words or bytes (UNIT says which)
        !           909:      from STR_RTX to the first word or byte containing part of the field.  */
        !           910: 
        !           911:   if (GET_CODE (op0) == REG)
        !           912:     {
        !           913:       if (offset != 0
        !           914:          || GET_MODE_SIZE (GET_MODE (op0)) > UNITS_PER_WORD)
        !           915:        op0 = gen_rtx (SUBREG, TYPE_MODE (type_for_size (BITS_PER_WORD, 0)),
        !           916:                       op0, offset);
        !           917:       offset = 0;
        !           918:     }
        !           919:   else
        !           920:     {
        !           921:       op0 = protect_from_queue (str_rtx, 1);
        !           922:     }
        !           923: 
        !           924:   /* Now OFFSET is nonzero only for memory operands.  */
        !           925: 
        !           926:   if (unsignedp)
        !           927:     {
        !           928: #ifdef HAVE_extzv
        !           929:       if (HAVE_extzv
        !           930:          && (GET_MODE_BITSIZE (insn_operand_mode[(int) CODE_FOR_extzv][0])
        !           931:              >= bitsize))
        !           932:        {
        !           933:          int xbitpos = bitpos, xoffset = offset;
        !           934:          rtx bitsize_rtx, bitpos_rtx;
        !           935:          rtx last = get_last_insn();
        !           936:          rtx xop0 = op0;
        !           937:          rtx xtarget = target;
        !           938:          rtx xspec_target = spec_target;
        !           939:          rtx xspec_target_subreg = spec_target_subreg;
        !           940:          rtx pat;
        !           941:          enum machine_mode maxmode
        !           942:            = insn_operand_mode[(int) CODE_FOR_extzv][0];
        !           943: 
        !           944:          if (GET_CODE (xop0) == MEM)
        !           945:            {
        !           946:              int save_volatile_ok = volatile_ok;
        !           947:              volatile_ok = 1;
        !           948: 
        !           949:              /* Is the memory operand acceptable?  */
        !           950:              if (flag_force_mem
        !           951:                  || ! ((*insn_operand_predicate[(int) CODE_FOR_extzv][1])
        !           952:                        (xop0, GET_MODE (xop0))))
        !           953:                {
        !           954:                  /* No, load into a reg and extract from there.  */
        !           955:                  enum machine_mode bestmode;
        !           956: 
        !           957:                  /* Get the mode to use for inserting into this field.  If
        !           958:                     OP0 is BLKmode, get the smallest mode consistent with the
        !           959:                     alignment. If OP0 is a non-BLKmode object that is no
        !           960:                     wider than MAXMODE, use its mode. Otherwise, use the
        !           961:                     smallest mode containing the field.  */
        !           962: 
        !           963:                  if (GET_MODE (xop0) == BLKmode
        !           964:                      || (GET_MODE_SIZE (GET_MODE (op0))
        !           965:                          > GET_MODE_SIZE (maxmode)))
        !           966:                    bestmode = get_best_mode (bitsize, bitnum,
        !           967:                                              align * BITS_PER_UNIT, maxmode,
        !           968:                                              MEM_VOLATILE_P (xop0));
        !           969:                  else
        !           970:                    bestmode = GET_MODE (xop0);
        !           971: 
        !           972:                  if (bestmode == VOIDmode
        !           973:                      || (STRICT_ALIGNMENT && GET_MODE_SIZE (bestmode) > align))
        !           974:                    goto extzv_loses;
        !           975: 
        !           976:                  /* Compute offset as multiple of this unit,
        !           977:                     counting in bytes.  */
        !           978:                  unit = GET_MODE_BITSIZE (bestmode);
        !           979:                  xoffset = (bitnum / unit) * GET_MODE_SIZE (bestmode);
        !           980:                  xbitpos = bitnum % unit;
        !           981:                  xop0 = change_address (xop0, bestmode,
        !           982:                                         plus_constant (XEXP (xop0, 0),
        !           983:                                                        xoffset));
        !           984:                  /* Fetch it to a register in that size.  */
        !           985:                  xop0 = force_reg (bestmode, xop0);
        !           986: 
        !           987:                  /* XBITPOS counts within UNIT, which is what is expected.  */
        !           988:                }
        !           989:              else
        !           990:                /* Get ref to first byte containing part of the field.  */
        !           991:                xop0 = change_address (xop0, byte_mode,
        !           992:                                       plus_constant (XEXP (xop0, 0), xoffset));
        !           993: 
        !           994:              volatile_ok = save_volatile_ok;
        !           995:            }
        !           996: 
        !           997:          /* If op0 is a register, we need it in MAXMODE (which is usually
        !           998:             SImode). to make it acceptable to the format of extzv.  */
        !           999:          if (GET_CODE (xop0) == SUBREG && GET_MODE (xop0) != maxmode)
        !          1000:            abort ();
        !          1001:          if (GET_CODE (xop0) == REG && GET_MODE (xop0) != maxmode)
        !          1002:            xop0 = gen_rtx (SUBREG, maxmode, xop0, 0);
        !          1003: 
        !          1004:          /* On big-endian machines, we count bits from the most significant.
        !          1005:             If the bit field insn does not, we must invert.  */
        !          1006: #if BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN
        !          1007:          xbitpos = unit - bitsize - xbitpos;
        !          1008: #endif
        !          1009:          /* Now convert from counting within UNIT to counting in MAXMODE.  */
        !          1010: #if BITS_BIG_ENDIAN
        !          1011:          if (GET_CODE (xop0) != MEM)
        !          1012:            xbitpos += GET_MODE_BITSIZE (maxmode) - unit;
        !          1013: #endif
        !          1014:          unit = GET_MODE_BITSIZE (maxmode);
        !          1015: 
        !          1016:          if (xtarget == 0
        !          1017:              || (flag_force_mem && GET_CODE (xtarget) == MEM))
        !          1018:            xtarget = xspec_target = gen_reg_rtx (tmode);
        !          1019: 
        !          1020:          if (GET_MODE (xtarget) != maxmode)
        !          1021:            {
        !          1022:              if (GET_CODE (xtarget) == REG)
        !          1023:                {
        !          1024:                  int wider = (GET_MODE_SIZE (maxmode)
        !          1025:                               > GET_MODE_SIZE (GET_MODE (xtarget)));
        !          1026:                  xtarget = gen_lowpart (maxmode, xtarget);
        !          1027:                  if (wider)
        !          1028:                    xspec_target_subreg = xtarget;
        !          1029:                }
        !          1030:              else
        !          1031:                xtarget = gen_reg_rtx (maxmode);
        !          1032:            }
        !          1033: 
        !          1034:          /* If this machine's extzv insists on a register target,
        !          1035:             make sure we have one.  */
        !          1036:          if (! ((*insn_operand_predicate[(int) CODE_FOR_extzv][0])
        !          1037:                 (xtarget, maxmode)))
        !          1038:            xtarget = gen_reg_rtx (maxmode);
        !          1039: 
        !          1040:          bitsize_rtx = GEN_INT (bitsize);
        !          1041:          bitpos_rtx = GEN_INT (xbitpos);
        !          1042: 
        !          1043:          pat = gen_extzv (protect_from_queue (xtarget, 1),
        !          1044:                           xop0, bitsize_rtx, bitpos_rtx);
        !          1045:          if (pat)
        !          1046:            {
        !          1047:              emit_insn (pat);
        !          1048:              target = xtarget;
        !          1049:              spec_target = xspec_target;
        !          1050:              spec_target_subreg = xspec_target_subreg;
        !          1051:            }
        !          1052:          else
        !          1053:            {
        !          1054:              delete_insns_since (last);
        !          1055:              target = extract_fixed_bit_field (tmode, op0, offset, bitsize,
        !          1056:                                                bitpos, target, 1, align);
        !          1057:            }
        !          1058:        }
        !          1059:       else
        !          1060:         extzv_loses:
        !          1061: #endif
        !          1062:        target = extract_fixed_bit_field (tmode, op0, offset, bitsize, bitpos,
        !          1063:                                          target, 1, align);
        !          1064:     }
        !          1065:   else
        !          1066:     {
        !          1067: #ifdef HAVE_extv
        !          1068:       if (HAVE_extv
        !          1069:          && (GET_MODE_BITSIZE (insn_operand_mode[(int) CODE_FOR_extv][0])
        !          1070:              >= bitsize))
        !          1071:        {
        !          1072:          int xbitpos = bitpos, xoffset = offset;
        !          1073:          rtx bitsize_rtx, bitpos_rtx;
        !          1074:          rtx last = get_last_insn();
        !          1075:          rtx xop0 = op0, xtarget = target;
        !          1076:          rtx xspec_target = spec_target;
        !          1077:          rtx xspec_target_subreg = spec_target_subreg;
        !          1078:          rtx pat;
        !          1079:          enum machine_mode maxmode
        !          1080:            = insn_operand_mode[(int) CODE_FOR_extv][0];
        !          1081: 
        !          1082:          if (GET_CODE (xop0) == MEM)
        !          1083:            {
        !          1084:              /* Is the memory operand acceptable?  */
        !          1085:              if (! ((*insn_operand_predicate[(int) CODE_FOR_extv][1])
        !          1086:                     (xop0, GET_MODE (xop0))))
        !          1087:                {
        !          1088:                  /* No, load into a reg and extract from there.  */
        !          1089:                  enum machine_mode bestmode;
        !          1090: 
        !          1091:                  /* Get the mode to use for inserting into this field.  If
        !          1092:                     OP0 is BLKmode, get the smallest mode consistent with the
        !          1093:                     alignment. If OP0 is a non-BLKmode object that is no
        !          1094:                     wider than MAXMODE, use its mode. Otherwise, use the
        !          1095:                     smallest mode containing the field.  */
        !          1096: 
        !          1097:                  if (GET_MODE (xop0) == BLKmode
        !          1098:                      || (GET_MODE_SIZE (GET_MODE (op0))
        !          1099:                          > GET_MODE_SIZE (maxmode)))
        !          1100:                    bestmode = get_best_mode (bitsize, bitnum,
        !          1101:                                              align * BITS_PER_UNIT, maxmode,
        !          1102:                                              MEM_VOLATILE_P (xop0));
        !          1103:                  else
        !          1104:                    bestmode = GET_MODE (xop0);
        !          1105: 
        !          1106:                  if (bestmode == VOIDmode
        !          1107:                      || (STRICT_ALIGNMENT && GET_MODE_SIZE (bestmode) > align))
        !          1108:                    goto extv_loses;
        !          1109: 
        !          1110:                  /* Compute offset as multiple of this unit,
        !          1111:                     counting in bytes.  */
        !          1112:                  unit = GET_MODE_BITSIZE (bestmode);
        !          1113:                  xoffset = (bitnum / unit) * GET_MODE_SIZE (bestmode);
        !          1114:                  xbitpos = bitnum % unit;
        !          1115:                  xop0 = change_address (xop0, bestmode,
        !          1116:                                         plus_constant (XEXP (xop0, 0),
        !          1117:                                                        xoffset));
        !          1118:                  /* Fetch it to a register in that size.  */
        !          1119:                  xop0 = force_reg (bestmode, xop0);
        !          1120: 
        !          1121:                  /* XBITPOS counts within UNIT, which is what is expected.  */
        !          1122:                }
        !          1123:              else
        !          1124:                /* Get ref to first byte containing part of the field.  */
        !          1125:                xop0 = change_address (xop0, byte_mode,
        !          1126:                                       plus_constant (XEXP (xop0, 0), xoffset));
        !          1127:            }
        !          1128: 
        !          1129:          /* If op0 is a register, we need it in MAXMODE (which is usually
        !          1130:             SImode) to make it acceptable to the format of extv.  */
        !          1131:          if (GET_CODE (xop0) == SUBREG && GET_MODE (xop0) != maxmode)
        !          1132:            abort ();
        !          1133:          if (GET_CODE (xop0) == REG && GET_MODE (xop0) != maxmode)
        !          1134:            xop0 = gen_rtx (SUBREG, maxmode, xop0, 0);
        !          1135: 
        !          1136:          /* On big-endian machines, we count bits from the most significant.
        !          1137:             If the bit field insn does not, we must invert.  */
        !          1138: #if BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN
        !          1139:          xbitpos = unit - bitsize - xbitpos;
        !          1140: #endif
        !          1141:          /* XBITPOS counts within a size of UNIT.
        !          1142:             Adjust to count within a size of MAXMODE.  */
        !          1143: #if BITS_BIG_ENDIAN
        !          1144:          if (GET_CODE (xop0) != MEM)
        !          1145:            xbitpos += (GET_MODE_BITSIZE (maxmode) - unit);
        !          1146: #endif
        !          1147:          unit = GET_MODE_BITSIZE (maxmode);
        !          1148: 
        !          1149:          if (xtarget == 0
        !          1150:              || (flag_force_mem && GET_CODE (xtarget) == MEM))
        !          1151:            xtarget = xspec_target = gen_reg_rtx (tmode);
        !          1152: 
        !          1153:          if (GET_MODE (xtarget) != maxmode)
        !          1154:            {
        !          1155:              if (GET_CODE (xtarget) == REG)
        !          1156:                {
        !          1157:                  int wider = (GET_MODE_SIZE (maxmode)
        !          1158:                               > GET_MODE_SIZE (GET_MODE (xtarget)));
        !          1159:                  xtarget = gen_lowpart (maxmode, xtarget);
        !          1160:                  if (wider)
        !          1161:                    xspec_target_subreg = xtarget;
        !          1162:                }
        !          1163:              else
        !          1164:                xtarget = gen_reg_rtx (maxmode);
        !          1165:            }
        !          1166: 
        !          1167:          /* If this machine's extv insists on a register target,
        !          1168:             make sure we have one.  */
        !          1169:          if (! ((*insn_operand_predicate[(int) CODE_FOR_extv][0])
        !          1170:                 (xtarget, maxmode)))
        !          1171:            xtarget = gen_reg_rtx (maxmode);
        !          1172: 
        !          1173:          bitsize_rtx = GEN_INT (bitsize);
        !          1174:          bitpos_rtx = GEN_INT (xbitpos);
        !          1175: 
        !          1176:          pat = gen_extv (protect_from_queue (xtarget, 1),
        !          1177:                          xop0, bitsize_rtx, bitpos_rtx);
        !          1178:          if (pat)
        !          1179:            {
        !          1180:              emit_insn (pat);
        !          1181:              target = xtarget;
        !          1182:              spec_target = xspec_target;
        !          1183:              spec_target_subreg = xspec_target_subreg;
        !          1184:            }
        !          1185:          else
        !          1186:            {
        !          1187:              delete_insns_since (last);
        !          1188:              target = extract_fixed_bit_field (tmode, op0, offset, bitsize,
        !          1189:                                                bitpos, target, 0, align);
        !          1190:            }
        !          1191:        } 
        !          1192:       else
        !          1193:        extv_loses:
        !          1194: #endif
        !          1195:        target = extract_fixed_bit_field (tmode, op0, offset, bitsize, bitpos,
        !          1196:                                          target, 0, align);
        !          1197:     }
        !          1198:   if (target == spec_target)
        !          1199:     return target;
        !          1200:   if (target == spec_target_subreg)
        !          1201:     return spec_target;
        !          1202:   if (GET_MODE (target) != tmode && GET_MODE (target) != mode)
        !          1203:     {
        !          1204:       /* If the target mode is floating-point, first convert to the
        !          1205:         integer mode of that size and then access it as a floating-point
        !          1206:         value via a SUBREG.  */
        !          1207:       if (GET_MODE_CLASS (tmode) == MODE_FLOAT)
        !          1208:        {
        !          1209:          target = convert_to_mode (mode_for_size (GET_MODE_BITSIZE (tmode),
        !          1210:                                                   MODE_INT, 0),
        !          1211:                                    target, unsignedp);
        !          1212:          if (GET_CODE (target) != REG)
        !          1213:            target = copy_to_reg (target);
        !          1214:          return gen_rtx (SUBREG, tmode, target, 0);
        !          1215:        }
        !          1216:       else
        !          1217:        return convert_to_mode (tmode, target, unsignedp);
        !          1218:     }
        !          1219:   return target;
        !          1220: }
        !          1221: 
        !          1222: /* Extract a bit field using shifts and boolean operations
        !          1223:    Returns an rtx to represent the value.
        !          1224:    OP0 addresses a register (word) or memory (byte).
        !          1225:    BITPOS says which bit within the word or byte the bit field starts in.
        !          1226:    OFFSET says how many bytes farther the bit field starts;
        !          1227:     it is 0 if OP0 is a register.
        !          1228:    BITSIZE says how many bits long the bit field is.
        !          1229:     (If OP0 is a register, it may be narrower than a full word,
        !          1230:      but BITPOS still counts within a full word,
        !          1231:      which is significant on bigendian machines.)
        !          1232: 
        !          1233:    UNSIGNEDP is nonzero for an unsigned bit field (don't sign-extend value).
        !          1234:    If TARGET is nonzero, attempts to store the value there
        !          1235:    and return TARGET, but this is not guaranteed.
        !          1236:    If TARGET is not used, create a pseudo-reg of mode TMODE for the value.
        !          1237: 
        !          1238:    ALIGN is the alignment that STR_RTX is known to have, measured in bytes.  */
        !          1239: 
        !          1240: static rtx
        !          1241: extract_fixed_bit_field (tmode, op0, offset, bitsize, bitpos,
        !          1242:                         target, unsignedp, align)
        !          1243:      enum machine_mode tmode;
        !          1244:      register rtx op0, target;
        !          1245:      register int offset, bitsize, bitpos;
        !          1246:      int unsignedp;
        !          1247:      int align;
        !          1248: {
        !          1249:   int total_bits = BITS_PER_WORD;
        !          1250:   enum machine_mode mode;
        !          1251: 
        !          1252:   if (GET_CODE (op0) == SUBREG || GET_CODE (op0) == REG)
        !          1253:     {
        !          1254:       /* Special treatment for a bit field split across two registers.  */
        !          1255:       if (bitsize + bitpos > BITS_PER_WORD)
        !          1256:        return extract_split_bit_field (op0, bitsize, bitpos,
        !          1257:                                        unsignedp, align);
        !          1258:     }
        !          1259:   else
        !          1260:     {
        !          1261:       /* Get the proper mode to use for this field.  We want a mode that
        !          1262:         includes the entire field.  If such a mode would be larger than
        !          1263:         a word, we won't be doing the extraction the normal way.  */
        !          1264: 
        !          1265:       mode = get_best_mode (bitsize, bitpos + offset * BITS_PER_UNIT,
        !          1266:                            align * BITS_PER_UNIT, word_mode,
        !          1267:                            GET_CODE (op0) == MEM && MEM_VOLATILE_P (op0));
        !          1268: 
        !          1269:       if (mode == VOIDmode)
        !          1270:        /* The only way this should occur is if the field spans word
        !          1271:           boundaries.  */
        !          1272:        return extract_split_bit_field (op0, bitsize,
        !          1273:                                        bitpos + offset * BITS_PER_UNIT,
        !          1274:                                        unsignedp, align);
        !          1275: 
        !          1276:       total_bits = GET_MODE_BITSIZE (mode);
        !          1277: 
        !          1278:       /* Make sure bitpos is valid for the chosen mode.  Adjust BITPOS to
        !          1279:         be be in the range 0 to total_bits-1, and put any excess bytes in
        !          1280:         OFFSET.  */
        !          1281:       if (bitpos >= total_bits)
        !          1282:        {
        !          1283:          offset += (bitpos / total_bits) * (total_bits / BITS_PER_UNIT);
        !          1284:          bitpos -= ((bitpos / total_bits) * (total_bits / BITS_PER_UNIT)
        !          1285:                     * BITS_PER_UNIT);
        !          1286:        }
        !          1287: 
        !          1288:       /* Get ref to an aligned byte, halfword, or word containing the field.
        !          1289:         Adjust BITPOS to be position within a word,
        !          1290:         and OFFSET to be the offset of that word.
        !          1291:         Then alter OP0 to refer to that word.  */
        !          1292:       bitpos += (offset % (total_bits / BITS_PER_UNIT)) * BITS_PER_UNIT;
        !          1293:       offset -= (offset % (total_bits / BITS_PER_UNIT));
        !          1294:       op0 = change_address (op0, mode,
        !          1295:                            plus_constant (XEXP (op0, 0), offset));
        !          1296:     }
        !          1297: 
        !          1298:   mode = GET_MODE (op0);
        !          1299: 
        !          1300: #if BYTES_BIG_ENDIAN
        !          1301:   /* BITPOS is the distance between our msb and that of OP0.
        !          1302:      Convert it to the distance from the lsb.  */
        !          1303: 
        !          1304:   bitpos = total_bits - bitsize - bitpos;
        !          1305: #endif
        !          1306:   /* Now BITPOS is always the distance between the field's lsb and that of OP0.
        !          1307:      We have reduced the big-endian case to the little-endian case.  */
        !          1308: 
        !          1309:   if (unsignedp)
        !          1310:     {
        !          1311:       if (bitpos)
        !          1312:        {
        !          1313:          /* If the field does not already start at the lsb,
        !          1314:             shift it so it does.  */
        !          1315:          tree amount = build_int_2 (bitpos, 0);
        !          1316:          /* Maybe propagate the target for the shift.  */
        !          1317:          /* But not if we will return it--could confuse integrate.c.  */
        !          1318:          rtx subtarget = (target != 0 && GET_CODE (target) == REG
        !          1319:                           && !REG_FUNCTION_VALUE_P (target)
        !          1320:                           ? target : 0);
        !          1321:          if (tmode != mode) subtarget = 0;
        !          1322:          op0 = expand_shift (RSHIFT_EXPR, mode, op0, amount, subtarget, 1);
        !          1323:        }
        !          1324:       /* Convert the value to the desired mode.  */
        !          1325:       if (mode != tmode)
        !          1326:        op0 = convert_to_mode (tmode, op0, 1);
        !          1327: 
        !          1328:       /* Unless the msb of the field used to be the msb when we shifted,
        !          1329:         mask out the upper bits.  */
        !          1330: 
        !          1331:       if (GET_MODE_BITSIZE (mode) != bitpos + bitsize
        !          1332: #if 0
        !          1333: #ifdef SLOW_ZERO_EXTEND
        !          1334:          /* Always generate an `and' if
        !          1335:             we just zero-extended op0 and SLOW_ZERO_EXTEND, since it
        !          1336:             will combine fruitfully with the zero-extend. */
        !          1337:          || tmode != mode
        !          1338: #endif
        !          1339: #endif
        !          1340:          )
        !          1341:        return expand_binop (GET_MODE (op0), and_optab, op0,
        !          1342:                             mask_rtx (GET_MODE (op0), 0, bitsize, 0),
        !          1343:                             target, 1, OPTAB_LIB_WIDEN);
        !          1344:       return op0;
        !          1345:     }
        !          1346: 
        !          1347:   /* To extract a signed bit-field, first shift its msb to the msb of the word,
        !          1348:      then arithmetic-shift its lsb to the lsb of the word.  */
        !          1349:   op0 = force_reg (mode, op0);
        !          1350:   if (mode != tmode)
        !          1351:     target = 0;
        !          1352: 
        !          1353:   /* Find the narrowest integer mode that contains the field.  */
        !          1354: 
        !          1355:   for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
        !          1356:        mode = GET_MODE_WIDER_MODE (mode))
        !          1357:     if (GET_MODE_BITSIZE (mode) >= bitsize + bitpos)
        !          1358:       {
        !          1359:        op0 = convert_to_mode (mode, op0, 0);
        !          1360:        break;
        !          1361:       }
        !          1362: 
        !          1363:   if (GET_MODE_BITSIZE (mode) != (bitsize + bitpos))
        !          1364:     {
        !          1365:       tree amount = build_int_2 (GET_MODE_BITSIZE (mode) - (bitsize + bitpos), 0);
        !          1366:       /* Maybe propagate the target for the shift.  */
        !          1367:       /* But not if we will return the result--could confuse integrate.c.  */
        !          1368:       rtx subtarget = (target != 0 && GET_CODE (target) == REG
        !          1369:                       && ! REG_FUNCTION_VALUE_P (target)
        !          1370:                       ? target : 0);
        !          1371:       op0 = expand_shift (LSHIFT_EXPR, mode, op0, amount, subtarget, 1);
        !          1372:     }
        !          1373: 
        !          1374:   return expand_shift (RSHIFT_EXPR, mode, op0,
        !          1375:                       build_int_2 (GET_MODE_BITSIZE (mode) - bitsize, 0), 
        !          1376:                       target, 0);
        !          1377: }
        !          1378: 
        !          1379: /* Return a constant integer (CONST_INT or CONST_DOUBLE) mask value
        !          1380:    of mode MODE with BITSIZE ones followed by BITPOS zeros, or the
        !          1381:    complement of that if COMPLEMENT.  The mask is truncated if
        !          1382:    necessary to the width of mode MODE.  */
        !          1383: 
        !          1384: static rtx
        !          1385: mask_rtx (mode, bitpos, bitsize, complement)
        !          1386:      enum machine_mode mode;
        !          1387:      int bitpos, bitsize, complement;
        !          1388: {
        !          1389:   HOST_WIDE_INT masklow, maskhigh;
        !          1390: 
        !          1391:   if (bitpos < HOST_BITS_PER_WIDE_INT)
        !          1392:     masklow = (HOST_WIDE_INT) -1 << bitpos;
        !          1393:   else
        !          1394:     masklow = 0;
        !          1395: 
        !          1396:   if (bitpos + bitsize < HOST_BITS_PER_WIDE_INT)
        !          1397:     masklow &= ((unsigned HOST_WIDE_INT) -1
        !          1398:                >> (HOST_BITS_PER_WIDE_INT - bitpos - bitsize));
        !          1399:   
        !          1400:   if (bitpos <= HOST_BITS_PER_WIDE_INT)
        !          1401:     maskhigh = -1;
        !          1402:   else
        !          1403:     maskhigh = (HOST_WIDE_INT) -1 << (bitpos - HOST_BITS_PER_WIDE_INT);
        !          1404: 
        !          1405:   if (bitpos + bitsize > HOST_BITS_PER_WIDE_INT)
        !          1406:     maskhigh &= ((unsigned HOST_WIDE_INT) -1
        !          1407:                 >> (2 * HOST_BITS_PER_WIDE_INT - bitpos - bitsize));
        !          1408:   else
        !          1409:     maskhigh = 0;
        !          1410: 
        !          1411:   if (complement)
        !          1412:     {
        !          1413:       maskhigh = ~maskhigh;
        !          1414:       masklow = ~masklow;
        !          1415:     }
        !          1416: 
        !          1417:   return immed_double_const (masklow, maskhigh, mode);
        !          1418: }
        !          1419: 
        !          1420: /* Return a constant integer (CONST_INT or CONST_DOUBLE) rtx with the value
        !          1421:    VALUE truncated to BITSIZE bits and then shifted left BITPOS bits.  */
        !          1422: 
        !          1423: static rtx
        !          1424: lshift_value (mode, value, bitpos, bitsize)
        !          1425:      enum machine_mode mode;
        !          1426:      rtx value;
        !          1427:      int bitpos, bitsize;
        !          1428: {
        !          1429:   unsigned HOST_WIDE_INT v = INTVAL (value);
        !          1430:   HOST_WIDE_INT low, high;
        !          1431: 
        !          1432:   if (bitsize < HOST_BITS_PER_WIDE_INT)
        !          1433:     v &= ~((HOST_WIDE_INT) -1 << bitsize);
        !          1434: 
        !          1435:   if (bitpos < HOST_BITS_PER_WIDE_INT)
        !          1436:     {
        !          1437:       low = v << bitpos;
        !          1438:       high = (bitpos > 0 ? (v >> (HOST_BITS_PER_WIDE_INT - bitpos)) : 0);
        !          1439:     }
        !          1440:   else
        !          1441:     {
        !          1442:       low = 0;
        !          1443:       high = v << (bitpos - HOST_BITS_PER_WIDE_INT);
        !          1444:     }
        !          1445: 
        !          1446:   return immed_double_const (low, high, mode);
        !          1447: }
        !          1448: 
        !          1449: /* Extract a bit field that is split across two words
        !          1450:    and return an RTX for the result.
        !          1451: 
        !          1452:    OP0 is the REG, SUBREG or MEM rtx for the first of the two words.
        !          1453:    BITSIZE is the field width; BITPOS, position of its first bit, in the word.
        !          1454:    UNSIGNEDP is 1 if should zero-extend the contents; else sign-extend.
        !          1455: 
        !          1456:    ALIGN is the known alignment of OP0, measured in bytes.
        !          1457:    This is also the size of the memory objects to be used.  */
        !          1458: 
        !          1459: static rtx
        !          1460: extract_split_bit_field (op0, bitsize, bitpos, unsignedp, align)
        !          1461:      rtx op0;
        !          1462:      int bitsize, bitpos, unsignedp, align;
        !          1463: {
        !          1464:   /* Make sure UNIT isn't larger than BITS_PER_WORD, we can only handle that
        !          1465:      much at a time.  */
        !          1466:   int unit = MIN (align * BITS_PER_UNIT, BITS_PER_WORD);
        !          1467:   int bitsdone = 0;
        !          1468:   rtx result;
        !          1469:   int first = 1;
        !          1470: 
        !          1471:   while (bitsdone < bitsize)
        !          1472:     {
        !          1473:       int thissize;
        !          1474:       rtx part, word;
        !          1475:       int thispos;
        !          1476:       int offset;
        !          1477: 
        !          1478:       offset = (bitpos + bitsdone) / unit;
        !          1479:       thispos = (bitpos + bitsdone) % unit;
        !          1480: 
        !          1481:       /* THISSIZE must not overrun a word boundary.  Otherwise,
        !          1482:         extract_fixed_bit_field will call us again, and we will mutually
        !          1483:         recurse forever.  */
        !          1484:       thissize = MIN (bitsize - bitsdone, BITS_PER_WORD);
        !          1485:       thissize = MIN (thissize, unit - thispos);
        !          1486: 
        !          1487:       /* If OP0 is a register, then handle OFFSET here.
        !          1488:         In the register case, UNIT must be a whole word.  */
        !          1489:       if (GET_CODE (op0) == SUBREG || GET_CODE (op0) == REG)
        !          1490:        {
        !          1491:          word = operand_subword_force (op0, offset, GET_MODE (op0));
        !          1492:          offset = 0;
        !          1493:        }
        !          1494:       else
        !          1495:        word = op0;
        !          1496: 
        !          1497:       if (word == 0)
        !          1498:        abort ();
        !          1499: 
        !          1500:       /* Extract the parts in bit-counting order,
        !          1501:         whose meaning is determined by BYTES_PER_UNIT.
        !          1502:         OFFSET is in UNITs, and UNIT is in bits.
        !          1503:         extract_fixed_bit_field wants offset in bytes.  */
        !          1504:       part = extract_fixed_bit_field (word_mode, word,
        !          1505:                                      offset * unit / BITS_PER_UNIT,
        !          1506:                                      thissize, thispos, 0, 1, align);
        !          1507:       bitsdone += thissize;
        !          1508: 
        !          1509:       /* Shift this part into place for the result.  */
        !          1510: #if BYTES_BIG_ENDIAN
        !          1511:       if (bitsize != bitsdone)
        !          1512:        part = expand_shift (LSHIFT_EXPR, word_mode, part,
        !          1513:                             build_int_2 (bitsize - bitsdone, 0), 0, 1);
        !          1514: #else
        !          1515:       if (bitsdone != thissize)
        !          1516:        part = expand_shift (LSHIFT_EXPR, word_mode, part,
        !          1517:                             build_int_2 (bitsdone - thissize, 0), 0, 1);
        !          1518: #endif
        !          1519: 
        !          1520:       if (first)
        !          1521:        result = part;
        !          1522:       else
        !          1523:        /* Combine the parts with bitwise or.  This works
        !          1524:           because we extracted each part as an unsigned bit field.  */
        !          1525:        result = expand_binop (word_mode, ior_optab, part, result, NULL_RTX, 1,
        !          1526:                               OPTAB_LIB_WIDEN);
        !          1527: 
        !          1528:       first = 0;
        !          1529:     }
        !          1530: 
        !          1531:   /* Unsigned bit field: we are done.  */
        !          1532:   if (unsignedp)
        !          1533:     return result;
        !          1534:   /* Signed bit field: sign-extend with two arithmetic shifts.  */
        !          1535:   result = expand_shift (LSHIFT_EXPR, word_mode, result,
        !          1536:                         build_int_2 (BITS_PER_WORD - bitsize, 0),
        !          1537:                         NULL_RTX, 0);
        !          1538:   return expand_shift (RSHIFT_EXPR, word_mode, result,
        !          1539:                       build_int_2 (BITS_PER_WORD - bitsize, 0), NULL_RTX, 0);
        !          1540: }
        !          1541: 
        !          1542: /* Add INC into TARGET.  */
        !          1543: 
        !          1544: void
        !          1545: expand_inc (target, inc)
        !          1546:      rtx target, inc;
        !          1547: {
        !          1548:   rtx value = expand_binop (GET_MODE (target), add_optab,
        !          1549:                            target, inc,
        !          1550:                            target, 0, OPTAB_LIB_WIDEN);
        !          1551:   if (value != target)
        !          1552:     emit_move_insn (target, value);
        !          1553: }
        !          1554: 
        !          1555: /* Subtract DEC from TARGET.  */
        !          1556: 
        !          1557: void
        !          1558: expand_dec (target, dec)
        !          1559:      rtx target, dec;
        !          1560: {
        !          1561:   rtx value = expand_binop (GET_MODE (target), sub_optab,
        !          1562:                            target, dec,
        !          1563:                            target, 0, OPTAB_LIB_WIDEN);
        !          1564:   if (value != target)
        !          1565:     emit_move_insn (target, value);
        !          1566: }
        !          1567: 
        !          1568: /* Output a shift instruction for expression code CODE,
        !          1569:    with SHIFTED being the rtx for the value to shift,
        !          1570:    and AMOUNT the tree for the amount to shift by.
        !          1571:    Store the result in the rtx TARGET, if that is convenient.
        !          1572:    If UNSIGNEDP is nonzero, do a logical shift; otherwise, arithmetic.
        !          1573:    Return the rtx for where the value is.  */
        !          1574: 
        !          1575: rtx
        !          1576: expand_shift (code, mode, shifted, amount, target, unsignedp)
        !          1577:      enum tree_code code;
        !          1578:      register enum machine_mode mode;
        !          1579:      rtx shifted;
        !          1580:      tree amount;
        !          1581:      register rtx target;
        !          1582:      int unsignedp;
        !          1583: {
        !          1584:   register rtx op1, temp = 0;
        !          1585:   register int left = (code == LSHIFT_EXPR || code == LROTATE_EXPR);
        !          1586:   register int rotate = (code == LROTATE_EXPR || code == RROTATE_EXPR);
        !          1587:   int try;
        !          1588: 
        !          1589:   /* Previously detected shift-counts computed by NEGATE_EXPR
        !          1590:      and shifted in the other direction; but that does not work
        !          1591:      on all machines.  */
        !          1592: 
        !          1593:   op1 = expand_expr (amount, NULL_RTX, VOIDmode, 0);
        !          1594: 
        !          1595:   if (op1 == const0_rtx)
        !          1596:     return shifted;
        !          1597: 
        !          1598:   for (try = 0; temp == 0 && try < 3; try++)
        !          1599:     {
        !          1600:       enum optab_methods methods;
        !          1601: 
        !          1602:       if (try == 0)
        !          1603:        methods = OPTAB_DIRECT;
        !          1604:       else if (try == 1)
        !          1605:        methods = OPTAB_WIDEN;
        !          1606:       else
        !          1607:        methods = OPTAB_LIB_WIDEN;
        !          1608: 
        !          1609:       if (rotate)
        !          1610:        {
        !          1611:          /* Widening does not work for rotation.  */
        !          1612:          if (methods == OPTAB_WIDEN)
        !          1613:            continue;
        !          1614:          else if (methods == OPTAB_LIB_WIDEN)
        !          1615:            {
        !          1616:              /* If we are rotating by a constant that is valid and
        !          1617:                 we have been unable to open-code this by a rotation,
        !          1618:                 do it as the IOR of two shifts.  I.e., to rotate A
        !          1619:                 by N bits, compute (A << N) | ((unsigned) A >> (C - N))
        !          1620:                 where C is the bitsize of A.
        !          1621: 
        !          1622:                 It is theoretically possible that the target machine might
        !          1623:                 not be able to perform either shift and hence we would
        !          1624:                 be making two libcalls rather than just the one for the
        !          1625:                 shift (similarly if IOR could not be done).  We will allow
        !          1626:                 this extremely unlikely lossage to avoid complicating the
        !          1627:                 code below.  */
        !          1628: 
        !          1629:              if (GET_CODE (op1) == CONST_INT && INTVAL (op1) > 0
        !          1630:                  && INTVAL (op1) < GET_MODE_BITSIZE (mode))
        !          1631:                {
        !          1632:                  rtx subtarget = target == shifted ? 0 : target;
        !          1633:                  rtx temp1;
        !          1634:                  tree other_amount
        !          1635:                    = build_int_2 (GET_MODE_BITSIZE (mode) - INTVAL (op1), 0);
        !          1636: 
        !          1637:                  shifted = force_reg (mode, shifted);
        !          1638: 
        !          1639:                  temp = expand_shift (left ? LSHIFT_EXPR : RSHIFT_EXPR,
        !          1640:                                       mode, shifted, amount, subtarget, 1);
        !          1641:                  temp1 = expand_shift (left ? RSHIFT_EXPR : LSHIFT_EXPR,
        !          1642:                                        mode, shifted, other_amount, 0, 1);
        !          1643:                  return expand_binop (mode, ior_optab, temp, temp1, target,
        !          1644:                                       unsignedp, methods);
        !          1645:                }
        !          1646:              else
        !          1647:                methods = OPTAB_LIB;
        !          1648:            }
        !          1649: 
        !          1650:          temp = expand_binop (mode,
        !          1651:                               left ? rotl_optab : rotr_optab,
        !          1652:                               shifted, op1, target, unsignedp, methods);
        !          1653: 
        !          1654:          /* If we don't have the rotate, but we are rotating by a constant
        !          1655:             that is in range, try a rotate in the opposite direction.  */
        !          1656: 
        !          1657:          if (temp == 0 && GET_CODE (op1) == CONST_INT
        !          1658:              && INTVAL (op1) > 0 && INTVAL (op1) < GET_MODE_BITSIZE (mode))
        !          1659:            temp = expand_binop (mode,
        !          1660:                                 left ? rotr_optab : rotl_optab,
        !          1661:                                 shifted, 
        !          1662:                                 GEN_INT (GET_MODE_BITSIZE (mode)
        !          1663:                                          - INTVAL (op1)),
        !          1664:                                 target, unsignedp, methods);
        !          1665:        }
        !          1666:       else if (unsignedp)
        !          1667:        {
        !          1668:          temp = expand_binop (mode,
        !          1669:                               left ? lshl_optab : lshr_optab,
        !          1670:                               shifted, op1, target, unsignedp, methods);
        !          1671:          if (temp == 0 && left)
        !          1672:            temp = expand_binop (mode, ashl_optab,
        !          1673:                                 shifted, op1, target, unsignedp, methods);
        !          1674:        }
        !          1675: 
        !          1676:       /* Do arithmetic shifts.
        !          1677:         Also, if we are going to widen the operand, we can just as well
        !          1678:         use an arithmetic right-shift instead of a logical one.  */
        !          1679:       if (temp == 0 && ! rotate
        !          1680:          && (! unsignedp || (! left && methods == OPTAB_WIDEN)))
        !          1681:        {
        !          1682:          enum optab_methods methods1 = methods;
        !          1683: 
        !          1684:          /* If trying to widen a log shift to an arithmetic shift,
        !          1685:             don't accept an arithmetic shift of the same size.  */
        !          1686:          if (unsignedp)
        !          1687:            methods1 = OPTAB_MUST_WIDEN;
        !          1688: 
        !          1689:          /* Arithmetic shift */
        !          1690: 
        !          1691:          temp = expand_binop (mode,
        !          1692:                               left ? ashl_optab : ashr_optab,
        !          1693:                               shifted, op1, target, unsignedp, methods1);
        !          1694:        }
        !          1695: 
        !          1696: #ifdef HAVE_extzv
        !          1697:       /* We can do a logical (unsigned) right shift with a bit-field
        !          1698:         extract insn.  But first check if one of the above methods worked.  */
        !          1699:       if (temp != 0)
        !          1700:        return temp;
        !          1701: 
        !          1702:       if (unsignedp && code == RSHIFT_EXPR && ! BITS_BIG_ENDIAN && HAVE_extzv)
        !          1703:        {
        !          1704:          enum machine_mode output_mode
        !          1705:            = insn_operand_mode[(int) CODE_FOR_extzv][0];
        !          1706: 
        !          1707:          if ((methods == OPTAB_DIRECT && mode == output_mode)
        !          1708:              || (methods == OPTAB_WIDEN
        !          1709:                  && GET_MODE_SIZE (mode) < GET_MODE_SIZE (output_mode)))
        !          1710:            {
        !          1711:              rtx shifted1 = convert_modes (output_mode, mode,
        !          1712:                                            protect_from_queue (shifted, 0),
        !          1713:                                            1);
        !          1714:              enum machine_mode length_mode
        !          1715:                = insn_operand_mode[(int) CODE_FOR_extzv][2];
        !          1716:              enum machine_mode pos_mode
        !          1717:                = insn_operand_mode[(int) CODE_FOR_extzv][3];
        !          1718:              rtx target1 = 0;
        !          1719:              rtx last = get_last_insn ();
        !          1720:              rtx width;
        !          1721:              rtx xop1 = op1;
        !          1722:              rtx pat;
        !          1723: 
        !          1724:              if (target != 0)
        !          1725:                target1 = protect_from_queue (target, 1);
        !          1726: 
        !          1727:              /* We define extract insns as having OUTPUT_MODE in a register
        !          1728:                 and the mode of operand 1 in memory.  Since we want
        !          1729:                 OUTPUT_MODE, we will always force the operand into a
        !          1730:                 register.  At some point we might want to support MEM
        !          1731:                 directly. */
        !          1732:              shifted1 = force_reg (output_mode, shifted1);
        !          1733: 
        !          1734:              /* If we don't have or cannot use a suggested target,
        !          1735:                 make a place for the result, in the proper mode.  */
        !          1736:              if (methods == OPTAB_WIDEN || target1 == 0
        !          1737:                  || ! ((*insn_operand_predicate[(int) CODE_FOR_extzv][0])
        !          1738:                        (target1, output_mode)))
        !          1739:                target1 = gen_reg_rtx (output_mode);
        !          1740: 
        !          1741:              xop1 = protect_from_queue (xop1, 0);
        !          1742:              xop1 = convert_modes (pos_mode, TYPE_MODE (TREE_TYPE (amount)),
        !          1743:                                    xop1, TREE_UNSIGNED (TREE_TYPE (amount)));
        !          1744: 
        !          1745:              /* If this machine's extzv insists on a register for
        !          1746:                 operand 3 (position), arrange for that.  */
        !          1747:              if (! ((*insn_operand_predicate[(int) CODE_FOR_extzv][3])
        !          1748:                     (xop1, pos_mode)))
        !          1749:                xop1 = force_reg (pos_mode, xop1);
        !          1750: 
        !          1751:              /* WIDTH gets the width of the bit field to extract:
        !          1752:                 wordsize minus # bits to shift by.  */
        !          1753:              if (GET_CODE (xop1) == CONST_INT)
        !          1754:                width = GEN_INT (GET_MODE_BITSIZE (mode) - INTVAL (op1));
        !          1755:              else
        !          1756:                {
        !          1757:                  /* Now get the width in the proper mode.  */
        !          1758:                  op1 = protect_from_queue (op1, 0);
        !          1759:                  width = convert_to_mode (length_mode, op1,
        !          1760:                                           TREE_UNSIGNED (TREE_TYPE (amount)));
        !          1761: 
        !          1762:                  width = expand_binop (length_mode, sub_optab,
        !          1763:                                        GEN_INT (GET_MODE_BITSIZE (mode)),
        !          1764:                                        width, NULL_RTX, 0, OPTAB_LIB_WIDEN);
        !          1765:                }
        !          1766: 
        !          1767:              /* If this machine's extzv insists on a register for
        !          1768:                 operand 2 (length), arrange for that.  */
        !          1769:              if (! ((*insn_operand_predicate[(int) CODE_FOR_extzv][2])
        !          1770:                     (width, length_mode)))
        !          1771:                width = force_reg (length_mode, width);
        !          1772: 
        !          1773:              /* Now extract with WIDTH, omitting OP1 least sig bits.  */
        !          1774:              pat = gen_extzv (target1, shifted1, width, xop1);
        !          1775:              if (pat)
        !          1776:                {
        !          1777:                  emit_insn (pat);
        !          1778:                  temp = convert_to_mode (mode, target1, 1);
        !          1779:                }
        !          1780:              else
        !          1781:                delete_insns_since (last);
        !          1782:            }
        !          1783: 
        !          1784:          /* Can also do logical shift with signed bit-field extract
        !          1785:             followed by inserting the bit-field at a different position.
        !          1786:             That strategy is not yet implemented.  */
        !          1787:        }
        !          1788: #endif /* HAVE_extzv */
        !          1789:     }
        !          1790: 
        !          1791:   if (temp == 0)
        !          1792:     abort ();
        !          1793:   return temp;
        !          1794: }
        !          1795: 
        !          1796: enum alg_code { alg_zero, alg_m, alg_shift,
        !          1797:                  alg_add_t_m2, alg_sub_t_m2,
        !          1798:                  alg_add_factor, alg_sub_factor,
        !          1799:                  alg_add_t2_m, alg_sub_t2_m,
        !          1800:                  alg_add, alg_subtract, alg_factor, alg_shiftop };
        !          1801: 
        !          1802: /* This structure records a sequence of operations.
        !          1803:    `ops' is the number of operations recorded.
        !          1804:    `cost' is their total cost.
        !          1805:    The operations are stored in `op' and the corresponding
        !          1806:    logarithms of the integer coefficients in `log'.
        !          1807: 
        !          1808:    These are the operations:
        !          1809:    alg_zero            total := 0;
        !          1810:    alg_m               total := multiplicand;
        !          1811:    alg_shift           total := total * coeff
        !          1812:    alg_add_t_m2                total := total + multiplicand * coeff;
        !          1813:    alg_sub_t_m2                total := total - multiplicand * coeff;
        !          1814:    alg_add_factor      total := total * coeff + total;
        !          1815:    alg_sub_factor      total := total * coeff - total;
        !          1816:    alg_add_t2_m                total := total * coeff + multiplicand;
        !          1817:    alg_sub_t2_m                total := total * coeff - multiplicand;
        !          1818: 
        !          1819:    The first operand must be either alg_zero or alg_m.  */
        !          1820: 
        !          1821: struct algorithm
        !          1822: {
        !          1823:   short cost;
        !          1824:   short ops;
        !          1825:   /* The size of the OP and LOG fields are not directly related to the
        !          1826:      word size, but the worst-case algorithms will be if we have few
        !          1827:      consecutive ones or zeros, i.e., a multiplicand like 10101010101...
        !          1828:      In that case we will generate shift-by-2, add, shift-by-2, add,...,
        !          1829:      in total wordsize operations.  */
        !          1830:   enum alg_code op[MAX_BITS_PER_WORD];
        !          1831:   char log[MAX_BITS_PER_WORD];
        !          1832: };
        !          1833: 
        !          1834: /* Compute and return the best algorithm for multiplying by T.
        !          1835:    The algorithm must cost less than cost_limit
        !          1836:    If retval.cost >= COST_LIMIT, no algorithm was found and all
        !          1837:    other field of the returned struct are undefined.  */
        !          1838: 
        !          1839: static void
        !          1840: synth_mult (alg_out, t, cost_limit)
        !          1841:      struct algorithm *alg_out;
        !          1842:      unsigned HOST_WIDE_INT t;
        !          1843:      int cost_limit;
        !          1844: {
        !          1845:   int m;
        !          1846:   struct algorithm *best_alg
        !          1847:     = (struct algorithm *)alloca (sizeof (struct algorithm));
        !          1848:   struct algorithm *alg_in
        !          1849:     = (struct algorithm *)alloca (sizeof (struct algorithm));
        !          1850:   unsigned int cost;
        !          1851:   unsigned HOST_WIDE_INT q;
        !          1852: 
        !          1853:   /* Indicate that no algorithm is yet found.  If no algorithm
        !          1854:      is found, this value will be returned and indicate failure.  */
        !          1855:   alg_out->cost = cost_limit;
        !          1856: 
        !          1857:   if (cost_limit <= 0)
        !          1858:     return;
        !          1859: 
        !          1860:   /* t == 1 can be done in zero cost.  */
        !          1861:   if (t == 1)
        !          1862:     {
        !          1863:       alg_out->ops = 1;
        !          1864:       alg_out->cost = 0;
        !          1865:       alg_out->op[0] = alg_m;
        !          1866:       return;
        !          1867:     }
        !          1868: 
        !          1869:   /* t == 0 sometimes has a cost.  If it does and it exceeds our limit,
        !          1870:      fail now.  */
        !          1871:   if (t == 0)
        !          1872:     {
        !          1873:       if (zero_cost >= cost_limit)
        !          1874:        return;
        !          1875:       else
        !          1876:        {
        !          1877:          alg_out->ops = 1;
        !          1878:          alg_out->cost = zero_cost;
        !          1879:          alg_out->op[0] = alg_zero;
        !          1880:          return;
        !          1881:        }
        !          1882:     }
        !          1883: 
        !          1884:   /* If we have a group of zero bits at the low-order part of T, try
        !          1885:      multiplying by the remaining bits and then doing a shift.  */
        !          1886: 
        !          1887:   if ((t & 1) == 0)
        !          1888:     {
        !          1889:       m = floor_log2 (t & -t); /* m = number of low zero bits */
        !          1890:       q = t >> m;
        !          1891:       cost = shift_cost[m];
        !          1892:       synth_mult (alg_in, q, cost_limit - cost);
        !          1893: 
        !          1894:       cost += alg_in->cost;
        !          1895:       if (cost < cost_limit)
        !          1896:        {
        !          1897:          struct algorithm *x;
        !          1898:          x = alg_in, alg_in = best_alg, best_alg = x;
        !          1899:          best_alg->log[best_alg->ops] = m;
        !          1900:          best_alg->op[best_alg->ops] = alg_shift;
        !          1901:          cost_limit = cost;
        !          1902:        }
        !          1903:     }
        !          1904: 
        !          1905:   /* If we have an odd number, add or subtract one.  */
        !          1906:   if ((t & 1) != 0)
        !          1907:     {
        !          1908:       unsigned HOST_WIDE_INT w;
        !          1909: 
        !          1910:       for (w = 1; (w & t) != 0; w <<= 1)
        !          1911:        ;
        !          1912:       if (w > 2
        !          1913:          /* Reject the case where t is 3.
        !          1914:             Thus we prefer addition in that case.  */
        !          1915:          && t != 3)
        !          1916:        {
        !          1917:          /* T ends with ...111.  Multiply by (T + 1) and subtract 1.  */
        !          1918: 
        !          1919:          cost = add_cost;
        !          1920:          synth_mult (alg_in, t + 1, cost_limit - cost);
        !          1921: 
        !          1922:          cost += alg_in->cost;
        !          1923:          if (cost < cost_limit)
        !          1924:            {
        !          1925:              struct algorithm *x;
        !          1926:              x = alg_in, alg_in = best_alg, best_alg = x;
        !          1927:              best_alg->log[best_alg->ops] = 0;
        !          1928:              best_alg->op[best_alg->ops] = alg_sub_t_m2;
        !          1929:              cost_limit = cost;
        !          1930:            }
        !          1931:        }
        !          1932:       else
        !          1933:        {
        !          1934:          /* T ends with ...01 or ...011.  Multiply by (T - 1) and add 1.  */
        !          1935: 
        !          1936:          cost = add_cost;
        !          1937:          synth_mult (alg_in, t - 1, cost_limit - cost);
        !          1938: 
        !          1939:          cost += alg_in->cost;
        !          1940:          if (cost < cost_limit)
        !          1941:            {
        !          1942:              struct algorithm *x;
        !          1943:              x = alg_in, alg_in = best_alg, best_alg = x;
        !          1944:              best_alg->log[best_alg->ops] = 0;
        !          1945:              best_alg->op[best_alg->ops] = alg_add_t_m2;
        !          1946:              cost_limit = cost;
        !          1947:            }
        !          1948:        }
        !          1949:     }
        !          1950: 
        !          1951:   /* Look for factors of t of the form
        !          1952:      t = q(2**m +- 1), 2 <= m <= floor(log2(t - 1)).
        !          1953:      If we find such a factor, we can multiply by t using an algorithm that
        !          1954:      multiplies by q, shift the result by m and add/subtract it to itself.
        !          1955: 
        !          1956:      We search for large factors first and loop down, even if large factors
        !          1957:      are less probable than small; if we find a large factor we will find a
        !          1958:      good sequence quickly, and therefore be able to prune (by decreasing
        !          1959:      COST_LIMIT) the search.  */
        !          1960: 
        !          1961:   for (m = floor_log2 (t - 1); m >= 2; m--)
        !          1962:     {
        !          1963:       unsigned HOST_WIDE_INT d;
        !          1964: 
        !          1965:       d = ((unsigned HOST_WIDE_INT) 1 << m) + 1;
        !          1966:       if (t % d == 0 && t > d)
        !          1967:        {
        !          1968:          cost = MIN (shiftadd_cost[m], add_cost + shift_cost[m]);
        !          1969:          synth_mult (alg_in, t / d, cost_limit - cost);
        !          1970: 
        !          1971:          cost += alg_in->cost;
        !          1972:          if (cost < cost_limit)
        !          1973:            {
        !          1974:              struct algorithm *x;
        !          1975:              x = alg_in, alg_in = best_alg, best_alg = x;
        !          1976:              best_alg->log[best_alg->ops] = m;
        !          1977:              best_alg->op[best_alg->ops] = alg_add_factor;
        !          1978:              cost_limit = cost;
        !          1979:            }
        !          1980:          /* Other factors will have been taken care of in the recursion.  */
        !          1981:          break;
        !          1982:        }
        !          1983: 
        !          1984:       d = ((unsigned HOST_WIDE_INT) 1 << m) - 1;
        !          1985:       if (t % d == 0 && t > d)
        !          1986:        {
        !          1987:          cost = MIN (shiftsub_cost[m], add_cost + shift_cost[m]);
        !          1988:          synth_mult (alg_in, t / d, cost_limit - cost);
        !          1989: 
        !          1990:          cost += alg_in->cost;
        !          1991:          if (cost < cost_limit)
        !          1992:            {
        !          1993:              struct algorithm *x;
        !          1994:              x = alg_in, alg_in = best_alg, best_alg = x;
        !          1995:              best_alg->log[best_alg->ops] = m;
        !          1996:              best_alg->op[best_alg->ops] = alg_sub_factor;
        !          1997:              cost_limit = cost;
        !          1998:            }
        !          1999:          break;
        !          2000:        }
        !          2001:     }
        !          2002: 
        !          2003:   /* Try shift-and-add (load effective address) instructions,
        !          2004:      i.e. do a*3, a*5, a*9.  */
        !          2005:   if ((t & 1) != 0)
        !          2006:     {
        !          2007:       q = t - 1;
        !          2008:       q = q & -q;
        !          2009:       m = exact_log2 (q);
        !          2010:       if (m >= 0)
        !          2011:        {
        !          2012:          cost = shiftadd_cost[m];
        !          2013:          synth_mult (alg_in, (t - 1) >> m, cost_limit - cost);
        !          2014: 
        !          2015:          cost += alg_in->cost;
        !          2016:          if (cost < cost_limit)
        !          2017:            {
        !          2018:              struct algorithm *x;
        !          2019:              x = alg_in, alg_in = best_alg, best_alg = x;
        !          2020:              best_alg->log[best_alg->ops] = m;
        !          2021:              best_alg->op[best_alg->ops] = alg_add_t2_m;
        !          2022:              cost_limit = cost;
        !          2023:            }
        !          2024:        }
        !          2025: 
        !          2026:       q = t + 1;
        !          2027:       q = q & -q;
        !          2028:       m = exact_log2 (q);
        !          2029:       if (m >= 0)
        !          2030:        {
        !          2031:          cost = shiftsub_cost[m];
        !          2032:          synth_mult (alg_in, (t + 1) >> m, cost_limit - cost);
        !          2033: 
        !          2034:          cost += alg_in->cost;
        !          2035:          if (cost < cost_limit)
        !          2036:            {
        !          2037:              struct algorithm *x;
        !          2038:              x = alg_in, alg_in = best_alg, best_alg = x;
        !          2039:              best_alg->log[best_alg->ops] = m;
        !          2040:              best_alg->op[best_alg->ops] = alg_sub_t2_m;
        !          2041:              cost_limit = cost;
        !          2042:            }
        !          2043:        }
        !          2044:     }
        !          2045: 
        !          2046:   /* If we are getting a too long sequence for `struct algorithm'
        !          2047:      to record, make this search fail.  */
        !          2048:   if (best_alg->ops == MAX_BITS_PER_WORD)
        !          2049:     return;
        !          2050: 
        !          2051:   /* If cost_limit has not decreased since we stored it in alg_out->cost,
        !          2052:      we have not found any algorithm.  */
        !          2053:   if (cost_limit == alg_out->cost)
        !          2054:     return;
        !          2055: 
        !          2056:   /* Copy the algorithm from temporary space to the space at alg_out.
        !          2057:      We avoid using structure assignment because the majority of
        !          2058:      best_alg is normally undefined, and this is a critical function.  */
        !          2059:   alg_out->ops = best_alg->ops + 1;
        !          2060:   alg_out->cost = cost_limit;
        !          2061:   bcopy (best_alg->op, alg_out->op, alg_out->ops * sizeof *alg_out->op);
        !          2062:   bcopy (best_alg->log, alg_out->log, alg_out->ops * sizeof *alg_out->log);
        !          2063: }
        !          2064: 
        !          2065: /* Perform a multiplication and return an rtx for the result.
        !          2066:    MODE is mode of value; OP0 and OP1 are what to multiply (rtx's);
        !          2067:    TARGET is a suggestion for where to store the result (an rtx).
        !          2068: 
        !          2069:    We check specially for a constant integer as OP1.
        !          2070:    If you want this check for OP0 as well, then before calling
        !          2071:    you should swap the two operands if OP0 would be constant.  */
        !          2072: 
        !          2073: rtx
        !          2074: expand_mult (mode, op0, op1, target, unsignedp)
        !          2075:      enum machine_mode mode;
        !          2076:      register rtx op0, op1, target;
        !          2077:      int unsignedp;
        !          2078: {
        !          2079:   rtx const_op1 = op1;
        !          2080: 
        !          2081:   /* If we are multiplying in DImode, it may still be a win
        !          2082:      to try to work with shifts and adds.  */
        !          2083:   if (GET_CODE (op1) == CONST_DOUBLE
        !          2084:       && GET_MODE_CLASS (GET_MODE (op1)) == MODE_INT
        !          2085:       && HOST_BITS_PER_INT <= BITS_PER_WORD)
        !          2086:     {
        !          2087:       if ((CONST_DOUBLE_HIGH (op1) == 0 && CONST_DOUBLE_LOW (op1) >= 0)
        !          2088:          || (CONST_DOUBLE_HIGH (op1) == -1 && CONST_DOUBLE_LOW (op1) < 0))
        !          2089:        const_op1 = GEN_INT (CONST_DOUBLE_LOW (op1));
        !          2090:     }
        !          2091: 
        !          2092:   /* We used to test optimize here, on the grounds that it's better to
        !          2093:      produce a smaller program when -O is not used.
        !          2094:      But this causes such a terrible slowdown sometimes
        !          2095:      that it seems better to use synth_mult always.  */
        !          2096: 
        !          2097:   if (GET_CODE (const_op1) == CONST_INT)
        !          2098:     {
        !          2099:       struct algorithm alg;
        !          2100:       struct algorithm neg_alg;
        !          2101:       int negate = 0;
        !          2102:       HOST_WIDE_INT val = INTVAL (op1);
        !          2103:       HOST_WIDE_INT val_so_far;
        !          2104:       rtx insn;
        !          2105:       int mult_cost;
        !          2106: 
        !          2107:       /* Try to do the computation two ways: multiply by the negative of OP1
        !          2108:         and then negate, or do the multiplication directly.  The latter is
        !          2109:         usually faster for positive numbers and the former for negative
        !          2110:         numbers, but the opposite can be faster if the original value
        !          2111:         has a factor of 2**m +/- 1, while the negated value does not or
        !          2112:         vice versa.  */
        !          2113: 
        !          2114:       mult_cost = rtx_cost (gen_rtx (MULT, mode, op0, op1), SET);
        !          2115:       mult_cost = MIN (12 * add_cost, mult_cost);
        !          2116: 
        !          2117:       synth_mult (&alg, val, mult_cost);
        !          2118:       synth_mult (&neg_alg, - val,
        !          2119:                  (alg.cost < mult_cost ? alg.cost : mult_cost) - negate_cost);
        !          2120: 
        !          2121:       if (neg_alg.cost + negate_cost < alg.cost)
        !          2122:        alg = neg_alg, negate = 1;
        !          2123: 
        !          2124:       if (alg.cost < mult_cost)
        !          2125:        {
        !          2126:          /* We found something cheaper than a multiply insn.  */
        !          2127:          int opno;
        !          2128:          rtx accum, tem;
        !          2129: 
        !          2130:          op0 = protect_from_queue (op0, 0);
        !          2131: 
        !          2132:          /* Avoid referencing memory over and over.
        !          2133:             For speed, but also for correctness when mem is volatile.  */
        !          2134:          if (GET_CODE (op0) == MEM)
        !          2135:            op0 = force_reg (mode, op0);
        !          2136: 
        !          2137:          /* ACCUM starts out either as OP0 or as a zero, depending on
        !          2138:             the first operation.  */
        !          2139: 
        !          2140:          if (alg.op[0] == alg_zero)
        !          2141:            {
        !          2142:              accum = copy_to_mode_reg (mode, const0_rtx);
        !          2143:              val_so_far = 0;
        !          2144:            }
        !          2145:          else if (alg.op[0] == alg_m)
        !          2146:            {
        !          2147:              accum = copy_to_mode_reg (mode, op0);
        !          2148:              val_so_far = 1;
        !          2149:            }
        !          2150:          else
        !          2151:            abort ();
        !          2152: 
        !          2153:          for (opno = 1; opno < alg.ops; opno++)
        !          2154:            {
        !          2155:              int log = alg.log[opno];
        !          2156:              rtx shift_subtarget = preserve_subexpressions_p () ? 0 : accum;
        !          2157:              rtx add_target = opno == alg.ops - 1 && target != 0 ? target : 0;
        !          2158: 
        !          2159:              switch (alg.op[opno])
        !          2160:                {
        !          2161:                case alg_shift:
        !          2162:                  accum = expand_shift (LSHIFT_EXPR, mode, accum,
        !          2163:                                        build_int_2 (log, 0), NULL_RTX, 0);
        !          2164:                  val_so_far <<= log;
        !          2165:                  break;
        !          2166: 
        !          2167:                case alg_add_t_m2:
        !          2168:                  tem = expand_shift (LSHIFT_EXPR, mode, op0,
        !          2169:                                      build_int_2 (log, 0), NULL_RTX, 0);
        !          2170:                  accum = force_operand (gen_rtx (PLUS, mode, accum, tem),
        !          2171:                                         add_target ? add_target : accum);
        !          2172:                  val_so_far += (HOST_WIDE_INT) 1 << log;
        !          2173:                  break;
        !          2174: 
        !          2175:                case alg_sub_t_m2:
        !          2176:                  tem = expand_shift (LSHIFT_EXPR, mode, op0,
        !          2177:                                      build_int_2 (log, 0), NULL_RTX, 0);
        !          2178:                  accum = force_operand (gen_rtx (MINUS, mode, accum, tem),
        !          2179:                                         add_target ? add_target : accum);
        !          2180:                  val_so_far -= (HOST_WIDE_INT) 1 << log;
        !          2181:                  break;
        !          2182: 
        !          2183:                case alg_add_t2_m:
        !          2184:                  accum = expand_shift (LSHIFT_EXPR, mode, accum,
        !          2185:                                        build_int_2 (log, 0), accum, 0);
        !          2186:                  accum = force_operand (gen_rtx (PLUS, mode, accum, op0),
        !          2187:                                         add_target ? add_target : accum);
        !          2188:                  val_so_far = (val_so_far << log) + 1;
        !          2189:                  break;
        !          2190: 
        !          2191:                case alg_sub_t2_m:
        !          2192:                  accum = expand_shift (LSHIFT_EXPR, mode, accum,
        !          2193:                                        build_int_2 (log, 0), accum, 0);
        !          2194:                  accum = force_operand (gen_rtx (MINUS, mode, accum, op0),
        !          2195:                                         add_target ? add_target : accum);
        !          2196:                  val_so_far = (val_so_far << log) - 1;
        !          2197:                  break;
        !          2198: 
        !          2199:                case alg_add_factor:
        !          2200:                  tem = expand_shift (LSHIFT_EXPR, mode, accum,
        !          2201:                                      build_int_2 (log, 0), NULL_RTX, 0);
        !          2202:                  accum = force_operand (gen_rtx (PLUS, mode, accum, tem),
        !          2203:                                         add_target ? add_target : accum);
        !          2204:                  val_so_far += val_so_far << log;
        !          2205:                  break;
        !          2206: 
        !          2207:                case alg_sub_factor:
        !          2208:                  tem = expand_shift (LSHIFT_EXPR, mode, accum,
        !          2209:                                      build_int_2 (log, 0), NULL_RTX, 0);
        !          2210:                  accum = force_operand (gen_rtx (MINUS, mode, tem, accum),
        !          2211:                                         add_target ? add_target : tem);
        !          2212:                  val_so_far = (val_so_far << log) - val_so_far;
        !          2213:                  break;
        !          2214: 
        !          2215:                default:
        !          2216:                  abort ();;
        !          2217:                }
        !          2218: 
        !          2219:              /* Write a REG_EQUAL note on the last insn so that we can cse
        !          2220:                 multiplication sequences.  */
        !          2221: 
        !          2222:              insn = get_last_insn ();
        !          2223:              REG_NOTES (insn)
        !          2224:                = gen_rtx (EXPR_LIST, REG_EQUAL,
        !          2225:                           gen_rtx (MULT, mode, op0, GEN_INT (val_so_far)),
        !          2226:                           REG_NOTES (insn));
        !          2227:            }
        !          2228: 
        !          2229:          if (negate)
        !          2230:            {
        !          2231:              val_so_far = - val_so_far;
        !          2232:              accum = expand_unop (mode, neg_optab, accum, target, 0);
        !          2233:            }
        !          2234: 
        !          2235:          if (val != val_so_far)
        !          2236:            abort ();
        !          2237: 
        !          2238:          return accum;
        !          2239:        }
        !          2240:     }
        !          2241: 
        !          2242:   /* This used to use umul_optab if unsigned, but for non-widening multiply
        !          2243:      there is no difference between signed and unsigned.  */
        !          2244:   op0 = expand_binop (mode, smul_optab,
        !          2245:                      op0, op1, target, unsignedp, OPTAB_LIB_WIDEN);
        !          2246:   if (op0 == 0)
        !          2247:     abort ();
        !          2248:   return op0;
        !          2249: }
        !          2250: 
        !          2251: /* Emit the code to divide OP0 by OP1, putting the result in TARGET
        !          2252:    if that is convenient, and returning where the result is.
        !          2253:    You may request either the quotient or the remainder as the result;
        !          2254:    specify REM_FLAG nonzero to get the remainder.
        !          2255: 
        !          2256:    CODE is the expression code for which kind of division this is;
        !          2257:    it controls how rounding is done.  MODE is the machine mode to use.
        !          2258:    UNSIGNEDP nonzero means do unsigned division.  */
        !          2259: 
        !          2260: /* ??? For CEIL_MOD_EXPR, can compute incorrect remainder with ANDI
        !          2261:    and then correct it by or'ing in missing high bits
        !          2262:    if result of ANDI is nonzero.
        !          2263:    For ROUND_MOD_EXPR, can use ANDI and then sign-extend the result.
        !          2264:    This could optimize to a bfexts instruction.
        !          2265:    But C doesn't use these operations, so their optimizations are
        !          2266:    left for later.  */
        !          2267: 
        !          2268: rtx
        !          2269: expand_divmod (rem_flag, code, mode, op0, op1, target, unsignedp)
        !          2270:      int rem_flag;
        !          2271:      enum tree_code code;
        !          2272:      enum machine_mode mode;
        !          2273:      register rtx op0, op1, target;
        !          2274:      int unsignedp;
        !          2275: {
        !          2276:   register rtx result = 0;
        !          2277:   enum machine_mode compute_mode;
        !          2278:   int log = -1;
        !          2279:   int size;
        !          2280:   int can_clobber_op0;
        !          2281:   int mod_insn_no_good = 0;
        !          2282:   rtx adjusted_op0 = op0;
        !          2283:   optab optab1, optab2;
        !          2284: 
        !          2285:   /* We shouldn't be called with op1 == const1_rtx, but some of the
        !          2286:      code below will malfunction if we are, so check here and handle
        !          2287:      the special case if so.  */
        !          2288:   if (op1 == const1_rtx)
        !          2289:     return rem_flag ? const0_rtx : op0;
        !          2290: 
        !          2291:   if (target
        !          2292:       /* Don't use the function value register as a target
        !          2293:         since we have to read it as well as write it,
        !          2294:         and function-inlining gets confused by this.  */
        !          2295:       && ((REG_P (target) && REG_FUNCTION_VALUE_P (target))
        !          2296:          /* Don't clobber an operand while doing a multi-step calculation.  */
        !          2297:          || (rem_flag
        !          2298:              && (reg_mentioned_p (target, op0)
        !          2299:                  || (GET_CODE (op0) == MEM && GET_CODE (target) == MEM)))
        !          2300:          || reg_mentioned_p (target, op1)
        !          2301:          || (GET_CODE (op1) == MEM && GET_CODE (target) == MEM)))
        !          2302:     target = 0;
        !          2303: 
        !          2304:   /* See if we are dividing by 2**log, and hence will do it by shifting,
        !          2305:      which is really floor-division, or if we will really do a divide,
        !          2306:      and we assume that is trunc-division.
        !          2307: 
        !          2308:      We must correct the dividend by adding or subtracting something
        !          2309:      based on the divisor, in order to do the kind of rounding specified
        !          2310:      by CODE.  The correction depends on what kind of rounding is actually
        !          2311:      available, and that depends on whether we will shift or divide.
        !          2312: 
        !          2313:      In many of these cases it is possible to perform the operation by a
        !          2314:      clever series of logical operations (shifts and/or exclusive-ors).
        !          2315:      Although avoiding the jump has the advantage that it extends the basic
        !          2316:      block and allows further optimization, the branch-free code is normally
        !          2317:      at least one instruction longer in the (most common) case where the
        !          2318:      dividend is non-negative.  Performance measurements of the two
        !          2319:      alternatives show that the branch-free code is slightly faster on the
        !          2320:      IBM ROMP but slower on CISC processors (significantly slower on the
        !          2321:      VAX).  Accordingly, the jump code has been retained when BRANCH_COST
        !          2322:      is small.
        !          2323: 
        !          2324:      On machines where the jump code is slower, the cost of a DIV or MOD
        !          2325:      operation can be set small (less than twice that of an addition); in 
        !          2326:      that case, we pretend that we don't have a power of two and perform
        !          2327:      a normal division or modulus operation.  */
        !          2328: 
        !          2329:   if (GET_CODE (op1) == CONST_INT
        !          2330:       && ! ((code == TRUNC_MOD_EXPR || code == TRUNC_DIV_EXPR)
        !          2331:            && ! unsignedp
        !          2332:            && (rem_flag ? smod_pow2_cheap : sdiv_pow2_cheap)))
        !          2333:     log = exact_log2 (INTVAL (op1));
        !          2334: 
        !          2335:   /* Get the mode in which to perform this computation.  Normally it will
        !          2336:      be MODE, but sometimes we can't do the desired operation in MODE.
        !          2337:      If so, pick a wider mode in which we can do the operation.  Convert
        !          2338:      to that mode at the start to avoid repeated conversions.
        !          2339: 
        !          2340:      First see what operations we need.  These depend on the expression
        !          2341:      we are evaluating.  (We assume that divxx3 insns exist under the
        !          2342:      same conditions that modxx3 insns and that these insns don't normally
        !          2343:      fail.  If these assumptions are not correct, we may generate less
        !          2344:      efficient code in some cases.)
        !          2345: 
        !          2346:      Then see if we find a mode in which we can open-code that operation
        !          2347:      (either a division, modulus, or shift).  Finally, check for the smallest
        !          2348:      mode for which we can do the operation with a library call.  */
        !          2349: 
        !          2350:   optab1 = (log >= 0 ? (unsignedp ? lshr_optab : ashr_optab)
        !          2351:            : (unsignedp ? udiv_optab : sdiv_optab));
        !          2352:   optab2 = (log >= 0 ? optab1 : (unsignedp ? udivmod_optab : sdivmod_optab));
        !          2353: 
        !          2354:   for (compute_mode = mode; compute_mode != VOIDmode;
        !          2355:        compute_mode = GET_MODE_WIDER_MODE (compute_mode))
        !          2356:     if (optab1->handlers[(int) compute_mode].insn_code != CODE_FOR_nothing
        !          2357:        || optab2->handlers[(int) compute_mode].insn_code != CODE_FOR_nothing)
        !          2358:       break;
        !          2359: 
        !          2360:   if (compute_mode == VOIDmode)
        !          2361:     for (compute_mode = mode; compute_mode != VOIDmode;
        !          2362:         compute_mode = GET_MODE_WIDER_MODE (compute_mode))
        !          2363:       if (optab1->handlers[(int) compute_mode].libfunc
        !          2364:          || optab2->handlers[(int) compute_mode].libfunc)
        !          2365:        break;
        !          2366: 
        !          2367:   /* If we still couldn't find a mode, use MODE, but we'll probably abort
        !          2368:      in expand_binop.  */
        !          2369:   if (compute_mode == VOIDmode)
        !          2370:     compute_mode = mode;
        !          2371: 
        !          2372:   size = GET_MODE_BITSIZE (compute_mode);
        !          2373: 
        !          2374:   /* If OP0 is a register that is used as the target, we can modify
        !          2375:      it in place; otherwise, we have to ensure we copy OP0 before
        !          2376:      modifying it.  */
        !          2377:   can_clobber_op0 = (GET_CODE (op0) == REG && op0 == target);
        !          2378: 
        !          2379:   /* Now convert to the best mode to use.  Show we made a copy of OP0
        !          2380:      and hence we can clobber it (we cannot use a SUBREG to widen
        !          2381:      something.  */
        !          2382:   if (compute_mode != mode)
        !          2383:     {
        !          2384:       adjusted_op0 = op0 = convert_modes (compute_mode, mode, op0, unsignedp);
        !          2385:       can_clobber_op0 = 1;
        !          2386:       op1 = convert_modes (compute_mode, mode, op1, unsignedp);
        !          2387:     }
        !          2388: 
        !          2389:   /* If we are computing the remainder and one of the operands is a volatile
        !          2390:      MEM, copy it into a register.  */
        !          2391: 
        !          2392:   if (rem_flag && GET_CODE (op0) == MEM && MEM_VOLATILE_P (op0))
        !          2393:     adjusted_op0 = op0 = force_reg (compute_mode, op0), can_clobber_op0 = 1;
        !          2394:   if (rem_flag && GET_CODE (op1) == MEM && MEM_VOLATILE_P (op1))
        !          2395:     op1 = force_reg (compute_mode, op1);
        !          2396: 
        !          2397:   /* If we are computing the remainder, op0 will be needed later to calculate
        !          2398:      X - Y * (X / Y), therefore cannot be clobbered. */
        !          2399:   if (rem_flag)
        !          2400:     can_clobber_op0 = 0;
        !          2401: 
        !          2402:   /* See if we will need to modify ADJUSTED_OP0.  Note that this code
        !          2403:      must agree with that in the switch below.  */
        !          2404:   if (((code == TRUNC_MOD_EXPR || code == TRUNC_DIV_EXPR)
        !          2405:        && log >= 0 && ! unsignedp)
        !          2406:       || ((code == FLOOR_MOD_EXPR || code == FLOOR_DIV_EXPR)
        !          2407:          && log < 0 && ! unsignedp)
        !          2408:       || code == CEIL_MOD_EXPR || code == CEIL_DIV_EXPR
        !          2409:       || code == ROUND_MOD_EXPR || code == ROUND_DIV_EXPR)
        !          2410:     {
        !          2411:       /* If we want the remainder, we may need to use OP0, so make sure
        !          2412:         it and ADJUSTED_OP0 are in different registers.  We force OP0
        !          2413:         to a register in case it has any queued subexpressions, because
        !          2414:         emit_cmp_insn will call emit_queue.
        !          2415: 
        !          2416:         If we don't want the remainder, we aren't going to use OP0 anymore.
        !          2417:         However, if we cannot clobber OP0 (and hence ADJUSTED_OP0), we must
        !          2418:         make a copy of it, hopefully to TARGET.
        !          2419: 
        !          2420:         This code is somewhat tricky.  Note that if REM_FLAG is nonzero,
        !          2421:         CAN_CLOBBER_OP0 will be zero and we know that OP0 cannot
        !          2422:         equal TARGET.  */
        !          2423: 
        !          2424:       if (rem_flag)
        !          2425:        op0 = force_reg (compute_mode, op0);
        !          2426: 
        !          2427:       if (! can_clobber_op0)
        !          2428:        {
        !          2429:          if (target && GET_MODE (target) == compute_mode)
        !          2430:            adjusted_op0 = target;
        !          2431:          else
        !          2432:            adjusted_op0 = 0;
        !          2433:          adjusted_op0 = copy_to_suggested_reg (op0, adjusted_op0,
        !          2434:                                                compute_mode);
        !          2435:        }
        !          2436:     }
        !          2437: 
        !          2438:   /* Adjust ADJUSTED_OP0 as described above.  Unless CAN_CLOBBER_OP0
        !          2439:      is now non-zero, OP0 will retain it's original value.  */
        !          2440: 
        !          2441:   switch (code)
        !          2442:     {
        !          2443:     case TRUNC_MOD_EXPR:
        !          2444:     case TRUNC_DIV_EXPR:
        !          2445:       if (log >= 0 && ! unsignedp)
        !          2446:        {
        !          2447:          /* Here we need to add OP1-1 if OP0 is negative, 0 otherwise.
        !          2448:             This can be computed without jumps by arithmetically shifting
        !          2449:             OP0 right LOG-1 places and then shifting right logically
        !          2450:             SIZE-LOG bits.  The resulting value is unconditionally added
        !          2451:             to OP0.
        !          2452: 
        !          2453:             If OP0 cannot be modified in place, copy it, possibly to
        !          2454:             TARGET.  Note that we will have previously only allowed
        !          2455:             it to be modified in place if it is a register, so that
        !          2456:             after this `if', ADJUSTED_OP0 is known to be a
        !          2457:             register.  */
        !          2458:          if (log == 1 || BRANCH_COST >= 3)
        !          2459:            {
        !          2460:              rtx temp;
        !          2461: 
        !          2462:              temp = expand_shift (RSHIFT_EXPR, compute_mode, adjusted_op0,
        !          2463:                                   build_int_2 (log - 1, 0), NULL_RTX, 0);
        !          2464: 
        !          2465:              /* We cannot allow TEMP to be ADJUSTED_OP0 here.  */
        !          2466:              temp = expand_shift (RSHIFT_EXPR, compute_mode, temp,
        !          2467:                                   build_int_2 (size - log, 0),
        !          2468:                                   temp != adjusted_op0 ? temp : NULL_RTX, 1);
        !          2469: 
        !          2470:              adjusted_op0 = expand_binop (compute_mode, add_optab,
        !          2471:                                           adjusted_op0, temp, adjusted_op0,
        !          2472:                                           0, OPTAB_LIB_WIDEN);
        !          2473:            }
        !          2474:          else
        !          2475:            {
        !          2476:              rtx label = gen_label_rtx ();
        !          2477: 
        !          2478:              emit_cmp_insn (adjusted_op0, const0_rtx, GE, 
        !          2479:                             NULL_RTX, compute_mode, 0, 0);
        !          2480:              emit_jump_insn (gen_bge (label));
        !          2481:              expand_inc (adjusted_op0, plus_constant (op1, -1));
        !          2482:              emit_label (label);
        !          2483:            }
        !          2484:          mod_insn_no_good = 1;
        !          2485:        }
        !          2486:       break;
        !          2487: 
        !          2488:     case FLOOR_DIV_EXPR:
        !          2489:     case FLOOR_MOD_EXPR:
        !          2490:       if (log < 0 && ! unsignedp)
        !          2491:        {
        !          2492:          rtx label = gen_label_rtx ();
        !          2493: 
        !          2494:          emit_cmp_insn (adjusted_op0, const0_rtx, GE, 
        !          2495:                         NULL_RTX, compute_mode, 0, 0);
        !          2496:          emit_jump_insn (gen_bge (label));
        !          2497:          expand_dec (adjusted_op0, op1);
        !          2498:          expand_inc (adjusted_op0, const1_rtx);
        !          2499:          emit_label (label);
        !          2500:          mod_insn_no_good = 1;
        !          2501:        }
        !          2502:       break;
        !          2503: 
        !          2504:     case CEIL_DIV_EXPR:
        !          2505:     case CEIL_MOD_EXPR:
        !          2506:       if (log < 0)
        !          2507:        {
        !          2508:          rtx label = 0;
        !          2509:          if (! unsignedp)
        !          2510:            {
        !          2511:              label = gen_label_rtx ();
        !          2512:              emit_cmp_insn (adjusted_op0, const0_rtx, LE, 
        !          2513:                             NULL_RTX, compute_mode, 0, 0);
        !          2514:              emit_jump_insn (gen_ble (label));
        !          2515:            }
        !          2516:          expand_inc (adjusted_op0, op1);
        !          2517:          expand_dec (adjusted_op0, const1_rtx);
        !          2518:          if (! unsignedp)
        !          2519:            emit_label (label);
        !          2520:        }
        !          2521:       else
        !          2522:        adjusted_op0 = expand_binop (compute_mode, add_optab,
        !          2523:                                     adjusted_op0, plus_constant (op1, -1),
        !          2524:                                     adjusted_op0, 0, OPTAB_LIB_WIDEN);
        !          2525: 
        !          2526:       mod_insn_no_good = 1;
        !          2527:       break;
        !          2528: 
        !          2529:     case ROUND_DIV_EXPR:
        !          2530:     case ROUND_MOD_EXPR:
        !          2531:       if (log < 0)
        !          2532:        {
        !          2533:          op1 = expand_shift (RSHIFT_EXPR, compute_mode, op1,
        !          2534:                              integer_one_node, NULL_RTX, 0);
        !          2535:          if (! unsignedp)
        !          2536:            {
        !          2537:              if (BRANCH_COST >= 2)
        !          2538:                {
        !          2539:                  /* Negate OP1 if OP0 < 0.  Do this by computing a temporary
        !          2540:                     that has all bits equal to the sign bit and exclusive
        !          2541:                     or-ing it with OP1.  */
        !          2542:                  rtx temp = expand_shift (RSHIFT_EXPR, compute_mode,
        !          2543:                                           adjusted_op0,
        !          2544:                                           build_int_2 (size - 1, 0),
        !          2545:                                           NULL_RTX, 0);
        !          2546:                  op1 = expand_binop (compute_mode, xor_optab, op1, temp, op1,
        !          2547:                                      unsignedp, OPTAB_LIB_WIDEN);
        !          2548:                }
        !          2549:              else
        !          2550:                {
        !          2551:                  rtx label = gen_label_rtx ();
        !          2552:                  emit_cmp_insn (adjusted_op0, const0_rtx, GE, NULL_RTX,
        !          2553:                                 compute_mode, 0, 0);
        !          2554:                  emit_jump_insn (gen_bge (label));
        !          2555:                  expand_unop (compute_mode, neg_optab, op1, op1, 0);
        !          2556:                  emit_label (label);
        !          2557:                }
        !          2558:            }
        !          2559:          expand_inc (adjusted_op0, op1);
        !          2560:        }
        !          2561:       else
        !          2562:        expand_inc (adjusted_op0, GEN_INT (((HOST_WIDE_INT) 1 << log) / 2));
        !          2563: 
        !          2564:       mod_insn_no_good = 1;
        !          2565:       break;
        !          2566:     }
        !          2567: 
        !          2568:   if (rem_flag && !mod_insn_no_good)
        !          2569:     {
        !          2570:       /* Try to produce the remainder directly */
        !          2571:       if (log >= 0)
        !          2572:        result = expand_binop (compute_mode, and_optab, adjusted_op0,
        !          2573:                               GEN_INT (((HOST_WIDE_INT) 1 << log) - 1),
        !          2574:                               target, 1, OPTAB_LIB_WIDEN);
        !          2575:       else
        !          2576:        {
        !          2577:          /* See if we can do remainder without a library call.  */
        !          2578:          result = sign_expand_binop (mode, umod_optab, smod_optab,
        !          2579:                                      adjusted_op0, op1, target,
        !          2580:                                      unsignedp, OPTAB_WIDEN);
        !          2581:          if (result == 0)
        !          2582:            {
        !          2583:              /* No luck there.  Can we do remainder and divide at once
        !          2584:                 without a library call?  */
        !          2585:              result = gen_reg_rtx (compute_mode);
        !          2586:              if (! expand_twoval_binop (unsignedp
        !          2587:                                         ? udivmod_optab : sdivmod_optab,
        !          2588:                                         adjusted_op0, op1,
        !          2589:                                         NULL_RTX, result, unsignedp))
        !          2590:                result = 0;
        !          2591:            }
        !          2592:        }
        !          2593:     }
        !          2594: 
        !          2595:   if (result)
        !          2596:     return gen_lowpart (mode, result);
        !          2597: 
        !          2598:   /* Produce the quotient.  */
        !          2599:   if (log >= 0)
        !          2600:     result = expand_shift (RSHIFT_EXPR, compute_mode, adjusted_op0,
        !          2601:                           build_int_2 (log, 0), target, unsignedp);
        !          2602:   else if (rem_flag && !mod_insn_no_good)
        !          2603:     /* If producing quotient in order to subtract for remainder,
        !          2604:        and a remainder subroutine would be ok,
        !          2605:        don't use a divide subroutine.  */
        !          2606:     result = sign_expand_binop (compute_mode, udiv_optab, sdiv_optab,
        !          2607:                                adjusted_op0, op1, NULL_RTX, unsignedp,
        !          2608:                                OPTAB_WIDEN);
        !          2609:   else
        !          2610:     {
        !          2611:       /* Try a quotient insn, but not a library call.  */
        !          2612:       result = sign_expand_binop (compute_mode, udiv_optab, sdiv_optab,
        !          2613:                                  adjusted_op0, op1,
        !          2614:                                  rem_flag ? NULL_RTX : target,
        !          2615:                                  unsignedp, OPTAB_WIDEN);
        !          2616:       if (result == 0)
        !          2617:        {
        !          2618:          /* No luck there.  Try a quotient-and-remainder insn,
        !          2619:             keeping the quotient alone.  */
        !          2620:          result = gen_reg_rtx (compute_mode);
        !          2621:          if (! expand_twoval_binop (unsignedp ? udivmod_optab : sdivmod_optab,
        !          2622:                                     adjusted_op0, op1,
        !          2623:                                     result, NULL_RTX, unsignedp))
        !          2624:            result = 0;
        !          2625:        }
        !          2626: 
        !          2627:       /* If still no luck, use a library call.  */
        !          2628:       if (result == 0)
        !          2629:        result = sign_expand_binop (compute_mode, udiv_optab, sdiv_optab,
        !          2630:                                    adjusted_op0, op1,
        !          2631:                                    rem_flag ? NULL_RTX : target,
        !          2632:                                    unsignedp, OPTAB_LIB_WIDEN);
        !          2633:     }
        !          2634: 
        !          2635:   /* If we really want the remainder, get it by subtraction.  */
        !          2636:   if (rem_flag)
        !          2637:     {
        !          2638:       if (result == 0)
        !          2639:        /* No divide instruction either.  Use library for remainder.  */
        !          2640:        result = sign_expand_binop (compute_mode, umod_optab, smod_optab,
        !          2641:                                    op0, op1, target,
        !          2642:                                    unsignedp, OPTAB_LIB_WIDEN);
        !          2643:       else
        !          2644:        {
        !          2645:          /* We divided.  Now finish doing X - Y * (X / Y).  */
        !          2646:          result = expand_mult (compute_mode, result, op1, target, unsignedp);
        !          2647:          if (! result) abort ();
        !          2648:          result = expand_binop (compute_mode, sub_optab, op0,
        !          2649:                                 result, target, unsignedp, OPTAB_LIB_WIDEN);
        !          2650:        }
        !          2651:     }
        !          2652: 
        !          2653:   if (result == 0)
        !          2654:     abort ();
        !          2655: 
        !          2656:   return gen_lowpart (mode, result);
        !          2657: }
        !          2658: 
        !          2659: /* Return a tree node with data type TYPE, describing the value of X.
        !          2660:    Usually this is an RTL_EXPR, if there is no obvious better choice.
        !          2661:    X may be an expression, however we only support those expressions
        !          2662:    generated by loop.c.   */
        !          2663: 
        !          2664: tree
        !          2665: make_tree (type, x)
        !          2666:      tree type;
        !          2667:      rtx x;
        !          2668: {
        !          2669:   tree t;
        !          2670: 
        !          2671:   switch (GET_CODE (x))
        !          2672:     {
        !          2673:     case CONST_INT:
        !          2674:       t = build_int_2 (INTVAL (x),
        !          2675:                       TREE_UNSIGNED (type) || INTVAL (x) >= 0 ? 0 : -1);
        !          2676:       TREE_TYPE (t) = type;
        !          2677:       return t;
        !          2678: 
        !          2679:     case CONST_DOUBLE:
        !          2680:       if (GET_MODE (x) == VOIDmode)
        !          2681:        {
        !          2682:          t = build_int_2 (CONST_DOUBLE_LOW (x), CONST_DOUBLE_HIGH (x));
        !          2683:          TREE_TYPE (t) = type;
        !          2684:        }
        !          2685:       else
        !          2686:        {
        !          2687:          REAL_VALUE_TYPE d;
        !          2688: 
        !          2689:          REAL_VALUE_FROM_CONST_DOUBLE (d, x);
        !          2690:          t = build_real (type, d);
        !          2691:        }
        !          2692: 
        !          2693:       return t;
        !          2694:          
        !          2695:     case PLUS:
        !          2696:       return fold (build (PLUS_EXPR, type, make_tree (type, XEXP (x, 0)),
        !          2697:                          make_tree (type, XEXP (x, 1))));
        !          2698:                                                       
        !          2699:     case MINUS:
        !          2700:       return fold (build (MINUS_EXPR, type, make_tree (type, XEXP (x, 0)),
        !          2701:                          make_tree (type, XEXP (x, 1))));
        !          2702:                                                       
        !          2703:     case NEG:
        !          2704:       return fold (build1 (NEGATE_EXPR, type, make_tree (type, XEXP (x, 0))));
        !          2705: 
        !          2706:     case MULT:
        !          2707:       return fold (build (MULT_EXPR, type, make_tree (type, XEXP (x, 0)),
        !          2708:                          make_tree (type, XEXP (x, 1))));
        !          2709:                                                      
        !          2710:     case ASHIFT:
        !          2711:       return fold (build (LSHIFT_EXPR, type, make_tree (type, XEXP (x, 0)),
        !          2712:                          make_tree (type, XEXP (x, 1))));
        !          2713:                                                      
        !          2714:     case LSHIFTRT:
        !          2715:       return fold (convert (type,
        !          2716:                            build (RSHIFT_EXPR, unsigned_type (type),
        !          2717:                                   make_tree (unsigned_type (type),
        !          2718:                                              XEXP (x, 0)),
        !          2719:                                   make_tree (type, XEXP (x, 1)))));
        !          2720:                                                      
        !          2721:     case ASHIFTRT:
        !          2722:       return fold (convert (type,
        !          2723:                            build (RSHIFT_EXPR, signed_type (type),
        !          2724:                                   make_tree (signed_type (type), XEXP (x, 0)),
        !          2725:                                   make_tree (type, XEXP (x, 1)))));
        !          2726:                                                      
        !          2727:     case DIV:
        !          2728:       if (TREE_CODE (type) != REAL_TYPE)
        !          2729:        t = signed_type (type);
        !          2730:       else
        !          2731:        t = type;
        !          2732: 
        !          2733:       return fold (convert (type,
        !          2734:                            build (TRUNC_DIV_EXPR, t,
        !          2735:                                   make_tree (t, XEXP (x, 0)),
        !          2736:                                   make_tree (t, XEXP (x, 1)))));
        !          2737:     case UDIV:
        !          2738:       t = unsigned_type (type);
        !          2739:       return fold (convert (type,
        !          2740:                            build (TRUNC_DIV_EXPR, t,
        !          2741:                                   make_tree (t, XEXP (x, 0)),
        !          2742:                                   make_tree (t, XEXP (x, 1)))));
        !          2743:    default:
        !          2744:       t = make_node (RTL_EXPR);
        !          2745:       TREE_TYPE (t) = type;
        !          2746:       RTL_EXPR_RTL (t) = x;
        !          2747:       /* There are no insns to be output
        !          2748:         when this rtl_expr is used.  */
        !          2749:       RTL_EXPR_SEQUENCE (t) = 0;
        !          2750:       return t;
        !          2751:     }
        !          2752: }
        !          2753: 
        !          2754: /* Return an rtx representing the value of X * MULT + ADD.
        !          2755:    TARGET is a suggestion for where to store the result (an rtx).
        !          2756:    MODE is the machine mode for the computation.
        !          2757:    X and MULT must have mode MODE.  ADD may have a different mode.
        !          2758:    So can X (defaults to same as MODE).
        !          2759:    UNSIGNEDP is non-zero to do unsigned multiplication.
        !          2760:    This may emit insns.  */
        !          2761: 
        !          2762: rtx
        !          2763: expand_mult_add (x, target, mult, add, mode, unsignedp)
        !          2764:      rtx x, target, mult, add;
        !          2765:      enum machine_mode mode;
        !          2766:      int unsignedp;
        !          2767: {
        !          2768:   tree type = type_for_mode (mode, unsignedp);
        !          2769:   tree add_type = (GET_MODE (add) == VOIDmode
        !          2770:                   ? type : type_for_mode (GET_MODE (add), unsignedp));
        !          2771:   tree result =  fold (build (PLUS_EXPR, type,
        !          2772:                              fold (build (MULT_EXPR, type,
        !          2773:                                           make_tree (type, x),
        !          2774:                                           make_tree (type, mult))),
        !          2775:                              make_tree (add_type, add)));
        !          2776: 
        !          2777:   return expand_expr (result, target, VOIDmode, 0);
        !          2778: }
        !          2779: 
        !          2780: /* Compute the logical-and of OP0 and OP1, storing it in TARGET
        !          2781:    and returning TARGET.
        !          2782: 
        !          2783:    If TARGET is 0, a pseudo-register or constant is returned.  */
        !          2784: 
        !          2785: rtx
        !          2786: expand_and (op0, op1, target)
        !          2787:      rtx op0, op1, target;
        !          2788: {
        !          2789:   enum machine_mode mode = VOIDmode;
        !          2790:   rtx tem;
        !          2791: 
        !          2792:   if (GET_MODE (op0) != VOIDmode)
        !          2793:     mode = GET_MODE (op0);
        !          2794:   else if (GET_MODE (op1) != VOIDmode)
        !          2795:     mode = GET_MODE (op1);
        !          2796: 
        !          2797:   if (mode != VOIDmode)
        !          2798:     tem = expand_binop (mode, and_optab, op0, op1, target, 0, OPTAB_LIB_WIDEN);
        !          2799:   else if (GET_CODE (op0) == CONST_INT && GET_CODE (op1) == CONST_INT)
        !          2800:     tem = GEN_INT (INTVAL (op0) & INTVAL (op1));
        !          2801:   else
        !          2802:     abort ();
        !          2803: 
        !          2804:   if (target == 0)
        !          2805:     target = tem;
        !          2806:   else if (tem != target)
        !          2807:     emit_move_insn (target, tem);
        !          2808:   return target;
        !          2809: }
        !          2810: 
        !          2811: /* Emit a store-flags instruction for comparison CODE on OP0 and OP1
        !          2812:    and storing in TARGET.  Normally return TARGET.
        !          2813:    Return 0 if that cannot be done.
        !          2814: 
        !          2815:    MODE is the mode to use for OP0 and OP1 should they be CONST_INTs.  If
        !          2816:    it is VOIDmode, they cannot both be CONST_INT.  
        !          2817: 
        !          2818:    UNSIGNEDP is for the case where we have to widen the operands
        !          2819:    to perform the operation.  It says to use zero-extension.
        !          2820: 
        !          2821:    NORMALIZEP is 1 if we should convert the result to be either zero
        !          2822:    or one one.  Normalize is -1 if we should convert the result to be
        !          2823:    either zero or -1.  If NORMALIZEP is zero, the result will be left
        !          2824:    "raw" out of the scc insn.  */
        !          2825: 
        !          2826: rtx
        !          2827: emit_store_flag (target, code, op0, op1, mode, unsignedp, normalizep)
        !          2828:      rtx target;
        !          2829:      enum rtx_code code;
        !          2830:      rtx op0, op1;
        !          2831:      enum machine_mode mode;
        !          2832:      int unsignedp;
        !          2833:      int normalizep;
        !          2834: {
        !          2835:   rtx subtarget;
        !          2836:   enum insn_code icode;
        !          2837:   enum machine_mode compare_mode;
        !          2838:   enum machine_mode target_mode = GET_MODE (target);
        !          2839:   rtx tem;
        !          2840:   rtx last = 0;
        !          2841:   rtx pattern, comparison;
        !          2842: 
        !          2843:   if (mode == VOIDmode)
        !          2844:     mode = GET_MODE (op0);
        !          2845: 
        !          2846:   /* If one operand is constant, make it the second one.  Only do this
        !          2847:      if the other operand is not constant as well.  */
        !          2848: 
        !          2849:   if ((CONSTANT_P (op0) && ! CONSTANT_P (op1))
        !          2850:       || (GET_CODE (op0) == CONST_INT && GET_CODE (op1) != CONST_INT))
        !          2851:     {
        !          2852:       tem = op0;
        !          2853:       op0 = op1;
        !          2854:       op1 = tem;
        !          2855:       code = swap_condition (code);
        !          2856:     }
        !          2857: 
        !          2858:   /* For some comparisons with 1 and -1, we can convert this to 
        !          2859:      comparisons with zero.  This will often produce more opportunities for
        !          2860:      store-flag insns. */
        !          2861: 
        !          2862:   switch (code)
        !          2863:     {
        !          2864:     case LT:
        !          2865:       if (op1 == const1_rtx)
        !          2866:        op1 = const0_rtx, code = LE;
        !          2867:       break;
        !          2868:     case LE:
        !          2869:       if (op1 == constm1_rtx)
        !          2870:        op1 = const0_rtx, code = LT;
        !          2871:       break;
        !          2872:     case GE:
        !          2873:       if (op1 == const1_rtx)
        !          2874:        op1 = const0_rtx, code = GT;
        !          2875:       break;
        !          2876:     case GT:
        !          2877:       if (op1 == constm1_rtx)
        !          2878:        op1 = const0_rtx, code = GE;
        !          2879:       break;
        !          2880:     case GEU:
        !          2881:       if (op1 == const1_rtx)
        !          2882:        op1 = const0_rtx, code = NE;
        !          2883:       break;
        !          2884:     case LTU:
        !          2885:       if (op1 == const1_rtx)
        !          2886:        op1 = const0_rtx, code = EQ;
        !          2887:       break;
        !          2888:     }
        !          2889: 
        !          2890:   /* From now on, we won't change CODE, so set ICODE now.  */
        !          2891:   icode = setcc_gen_code[(int) code];
        !          2892: 
        !          2893:   /* If this is A < 0 or A >= 0, we can do this by taking the ones
        !          2894:      complement of A (for GE) and shifting the sign bit to the low bit.  */
        !          2895:   if (op1 == const0_rtx && (code == LT || code == GE)
        !          2896:       && GET_MODE_CLASS (mode) == MODE_INT
        !          2897:       && (normalizep || STORE_FLAG_VALUE == 1
        !          2898:          || (GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT
        !          2899:              && (STORE_FLAG_VALUE 
        !          2900:                  == (HOST_WIDE_INT) 1 << (GET_MODE_BITSIZE (mode) - 1)))))
        !          2901:     {
        !          2902:       subtarget = target;
        !          2903: 
        !          2904:       /* If the result is to be wider than OP0, it is best to convert it
        !          2905:         first.  If it is to be narrower, it is *incorrect* to convert it
        !          2906:         first.  */
        !          2907:       if (GET_MODE_SIZE (target_mode) > GET_MODE_SIZE (mode))
        !          2908:        {
        !          2909:          op0 = protect_from_queue (op0, 0);
        !          2910:          op0 = convert_modes (target_mode, mode, op0, 0);
        !          2911:          mode = target_mode;
        !          2912:        }
        !          2913: 
        !          2914:       if (target_mode != mode)
        !          2915:        subtarget = 0;
        !          2916: 
        !          2917:       if (code == GE)
        !          2918:        op0 = expand_unop (mode, one_cmpl_optab, op0, subtarget, 0);
        !          2919: 
        !          2920:       if (normalizep || STORE_FLAG_VALUE == 1)
        !          2921:        /* If we are supposed to produce a 0/1 value, we want to do
        !          2922:           a logical shift from the sign bit to the low-order bit; for
        !          2923:           a -1/0 value, we do an arithmetic shift.  */
        !          2924:        op0 = expand_shift (RSHIFT_EXPR, mode, op0,
        !          2925:                            size_int (GET_MODE_BITSIZE (mode) - 1),
        !          2926:                            subtarget, normalizep != -1);
        !          2927: 
        !          2928:       if (mode != target_mode)
        !          2929:        op0 = convert_modes (target_mode, mode, op0, 0);
        !          2930: 
        !          2931:       return op0;
        !          2932:     }
        !          2933: 
        !          2934:   if (icode != CODE_FOR_nothing)
        !          2935:     {
        !          2936:       /* We think we may be able to do this with a scc insn.  Emit the
        !          2937:         comparison and then the scc insn.
        !          2938: 
        !          2939:         compare_from_rtx may call emit_queue, which would be deleted below
        !          2940:         if the scc insn fails.  So call it ourselves before setting LAST.  */
        !          2941: 
        !          2942:       emit_queue ();
        !          2943:       last = get_last_insn ();
        !          2944: 
        !          2945:       comparison
        !          2946:        = compare_from_rtx (op0, op1, code, unsignedp, mode, NULL_RTX, 0);
        !          2947:       if (GET_CODE (comparison) == CONST_INT)
        !          2948:        return (comparison == const0_rtx ? const0_rtx
        !          2949:                : normalizep == 1 ? const1_rtx
        !          2950:                : normalizep == -1 ? constm1_rtx
        !          2951:                : const_true_rtx);
        !          2952: 
        !          2953:       /* If the code of COMPARISON doesn't match CODE, something is
        !          2954:         wrong; we can no longer be sure that we have the operation.  
        !          2955:         We could handle this case, but it should not happen.  */
        !          2956: 
        !          2957:       if (GET_CODE (comparison) != code)
        !          2958:        abort ();
        !          2959: 
        !          2960:       /* Get a reference to the target in the proper mode for this insn.  */
        !          2961:       compare_mode = insn_operand_mode[(int) icode][0];
        !          2962:       subtarget = target;
        !          2963:       if (preserve_subexpressions_p ()
        !          2964:          || ! (*insn_operand_predicate[(int) icode][0]) (subtarget, compare_mode))
        !          2965:        subtarget = gen_reg_rtx (compare_mode);
        !          2966: 
        !          2967:       pattern = GEN_FCN (icode) (subtarget);
        !          2968:       if (pattern)
        !          2969:        {
        !          2970:          emit_insn (pattern);
        !          2971: 
        !          2972:          /* If we are converting to a wider mode, first convert to
        !          2973:             TARGET_MODE, then normalize.  This produces better combining
        !          2974:             opportunities on machines that have a SIGN_EXTRACT when we are
        !          2975:             testing a single bit.  This mostly benefits the 68k.
        !          2976: 
        !          2977:             If STORE_FLAG_VALUE does not have the sign bit set when
        !          2978:             interpreted in COMPARE_MODE, we can do this conversion as
        !          2979:             unsigned, which is usually more efficient.  */
        !          2980:          if (GET_MODE_SIZE (target_mode) > GET_MODE_SIZE (compare_mode))
        !          2981:            {
        !          2982:              convert_move (target, subtarget,
        !          2983:                            (GET_MODE_BITSIZE (compare_mode)
        !          2984:                             <= HOST_BITS_PER_WIDE_INT)
        !          2985:                            && 0 == (STORE_FLAG_VALUE
        !          2986:                                     & ((HOST_WIDE_INT) 1
        !          2987:                                        << (GET_MODE_BITSIZE (compare_mode) -1))));
        !          2988:              op0 = target;
        !          2989:              compare_mode = target_mode;
        !          2990:            }
        !          2991:          else
        !          2992:            op0 = subtarget;
        !          2993: 
        !          2994:          /* If we want to keep subexpressions around, don't reuse our
        !          2995:             last target.  */
        !          2996: 
        !          2997:          if (preserve_subexpressions_p ())
        !          2998:            subtarget = 0;
        !          2999: 
        !          3000:          /* Now normalize to the proper value in COMPARE_MODE.  Sometimes
        !          3001:             we don't have to do anything.  */
        !          3002:          if (normalizep == 0 || normalizep == STORE_FLAG_VALUE)
        !          3003:            ;
        !          3004:          else if (normalizep == - STORE_FLAG_VALUE)
        !          3005:            op0 = expand_unop (compare_mode, neg_optab, op0, subtarget, 0);
        !          3006: 
        !          3007:          /* We don't want to use STORE_FLAG_VALUE < 0 below since this
        !          3008:             makes it hard to use a value of just the sign bit due to
        !          3009:             ANSI integer constant typing rules.  */
        !          3010:          else if (GET_MODE_BITSIZE (compare_mode) <= HOST_BITS_PER_WIDE_INT
        !          3011:                   && (STORE_FLAG_VALUE
        !          3012:                       & ((HOST_WIDE_INT) 1
        !          3013:                          << (GET_MODE_BITSIZE (compare_mode) - 1))))
        !          3014:            op0 = expand_shift (RSHIFT_EXPR, compare_mode, op0,
        !          3015:                                size_int (GET_MODE_BITSIZE (compare_mode) - 1),
        !          3016:                                subtarget, normalizep == 1);
        !          3017:          else if (STORE_FLAG_VALUE & 1)
        !          3018:            {
        !          3019:              op0 = expand_and (op0, const1_rtx, subtarget);
        !          3020:              if (normalizep == -1)
        !          3021:                op0 = expand_unop (compare_mode, neg_optab, op0, op0, 0);
        !          3022:            }
        !          3023:          else
        !          3024:            abort ();
        !          3025: 
        !          3026:          /* If we were converting to a smaller mode, do the 
        !          3027:             conversion now.  */
        !          3028:          if (target_mode != compare_mode)
        !          3029:            {
        !          3030:              convert_move (target, op0, 0);
        !          3031:              return target;
        !          3032:            }
        !          3033:          else
        !          3034:            return op0;
        !          3035:        }
        !          3036:     }
        !          3037: 
        !          3038:   if (last)
        !          3039:     delete_insns_since (last);
        !          3040: 
        !          3041:   subtarget = target_mode == mode ? target : 0;
        !          3042: 
        !          3043:   /* If we reached here, we can't do this with a scc insn.  However, there
        !          3044:      are some comparisons that can be done directly.  For example, if
        !          3045:      this is an equality comparison of integers, we can try to exclusive-or
        !          3046:      (or subtract) the two operands and use a recursive call to try the
        !          3047:      comparison with zero.  Don't do any of these cases if branches are
        !          3048:      very cheap.  */
        !          3049: 
        !          3050:   if (BRANCH_COST > 0
        !          3051:       && GET_MODE_CLASS (mode) == MODE_INT && (code == EQ || code == NE)
        !          3052:       && op1 != const0_rtx)
        !          3053:     {
        !          3054:       tem = expand_binop (mode, xor_optab, op0, op1, subtarget, 1,
        !          3055:                          OPTAB_WIDEN);
        !          3056: 
        !          3057:       if (tem == 0)
        !          3058:        tem = expand_binop (mode, sub_optab, op0, op1, subtarget, 1,
        !          3059:                            OPTAB_WIDEN);
        !          3060:       if (tem != 0)
        !          3061:        tem = emit_store_flag (target, code, tem, const0_rtx,
        !          3062:                               mode, unsignedp, normalizep);
        !          3063:       if (tem == 0)
        !          3064:        delete_insns_since (last);
        !          3065:       return tem;
        !          3066:     }
        !          3067: 
        !          3068:   /* Some other cases we can do are EQ, NE, LE, and GT comparisons with 
        !          3069:      the constant zero.  Reject all other comparisons at this point.  Only
        !          3070:      do LE and GT if branches are expensive since they are expensive on
        !          3071:      2-operand machines.  */
        !          3072: 
        !          3073:   if (BRANCH_COST == 0
        !          3074:       || GET_MODE_CLASS (mode) != MODE_INT || op1 != const0_rtx
        !          3075:       || (code != EQ && code != NE
        !          3076:          && (BRANCH_COST <= 1 || (code != LE && code != GT))))
        !          3077:     return 0;
        !          3078: 
        !          3079:   /* See what we need to return.  We can only return a 1, -1, or the
        !          3080:      sign bit.  */
        !          3081: 
        !          3082:   if (normalizep == 0)
        !          3083:     {
        !          3084:       if (STORE_FLAG_VALUE == 1 || STORE_FLAG_VALUE == -1)
        !          3085:        normalizep = STORE_FLAG_VALUE;
        !          3086: 
        !          3087:       else if (GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT
        !          3088:               && (STORE_FLAG_VALUE
        !          3089:                   == (HOST_WIDE_INT) 1 << (GET_MODE_BITSIZE (mode) - 1)))
        !          3090:        ;
        !          3091:       else
        !          3092:        return 0;
        !          3093:     }
        !          3094: 
        !          3095:   /* Try to put the result of the comparison in the sign bit.  Assume we can't
        !          3096:      do the necessary operation below.  */
        !          3097: 
        !          3098:   tem = 0;
        !          3099: 
        !          3100:   /* To see if A <= 0, compute (A | (A - 1)).  A <= 0 iff that result has
        !          3101:      the sign bit set.  */
        !          3102: 
        !          3103:   if (code == LE)
        !          3104:     {
        !          3105:       /* This is destructive, so SUBTARGET can't be OP0.  */
        !          3106:       if (rtx_equal_p (subtarget, op0))
        !          3107:        subtarget = 0;
        !          3108: 
        !          3109:       tem = expand_binop (mode, sub_optab, op0, const1_rtx, subtarget, 0,
        !          3110:                          OPTAB_WIDEN);
        !          3111:       if (tem)
        !          3112:        tem = expand_binop (mode, ior_optab, op0, tem, subtarget, 0,
        !          3113:                            OPTAB_WIDEN);
        !          3114:     }
        !          3115: 
        !          3116:   /* To see if A > 0, compute (((signed) A) << BITS) - A, where BITS is the
        !          3117:      number of bits in the mode of OP0, minus one.  */
        !          3118: 
        !          3119:   if (code == GT)
        !          3120:     {
        !          3121:       if (rtx_equal_p (subtarget, op0))
        !          3122:        subtarget = 0;
        !          3123: 
        !          3124:       tem = expand_shift (RSHIFT_EXPR, mode, op0,
        !          3125:                          size_int (GET_MODE_BITSIZE (mode) - 1),
        !          3126:                          subtarget, 0);
        !          3127:       tem = expand_binop (mode, sub_optab, tem, op0, subtarget, 0,
        !          3128:                          OPTAB_WIDEN);
        !          3129:     }
        !          3130:                                    
        !          3131:   if (code == EQ || code == NE)
        !          3132:     {
        !          3133:       /* For EQ or NE, one way to do the comparison is to apply an operation
        !          3134:         that converts the operand into a positive number if it is non-zero
        !          3135:         or zero if it was originally zero.  Then, for EQ, we subtract 1 and
        !          3136:         for NE we negate.  This puts the result in the sign bit.  Then we
        !          3137:         normalize with a shift, if needed. 
        !          3138: 
        !          3139:         Two operations that can do the above actions are ABS and FFS, so try
        !          3140:         them.  If that doesn't work, and MODE is smaller than a full word,
        !          3141:         we can use zero-extension to the wider mode (an unsigned conversion)
        !          3142:         as the operation.  */
        !          3143: 
        !          3144:       if (abs_optab->handlers[(int) mode].insn_code != CODE_FOR_nothing)
        !          3145:        tem = expand_unop (mode, abs_optab, op0, subtarget, 1);
        !          3146:       else if (ffs_optab->handlers[(int) mode].insn_code != CODE_FOR_nothing)
        !          3147:        tem = expand_unop (mode, ffs_optab, op0, subtarget, 1);
        !          3148:       else if (GET_MODE_SIZE (mode) < UNITS_PER_WORD)
        !          3149:        {
        !          3150:          op0 = protect_from_queue (op0, 0);
        !          3151:          tem = convert_modes (word_mode, mode, op0, 1);
        !          3152:          mode = word_mode;
        !          3153:        }
        !          3154: 
        !          3155:       if (tem != 0)
        !          3156:        {
        !          3157:          if (code == EQ)
        !          3158:            tem = expand_binop (mode, sub_optab, tem, const1_rtx, subtarget,
        !          3159:                                0, OPTAB_WIDEN);
        !          3160:          else
        !          3161:            tem = expand_unop (mode, neg_optab, tem, subtarget, 0);
        !          3162:        }
        !          3163: 
        !          3164:       /* If we couldn't do it that way, for NE we can "or" the two's complement
        !          3165:         of the value with itself.  For EQ, we take the one's complement of
        !          3166:         that "or", which is an extra insn, so we only handle EQ if branches
        !          3167:         are expensive.  */
        !          3168: 
        !          3169:       if (tem == 0 && (code == NE || BRANCH_COST > 1))
        !          3170:        {
        !          3171:          if (rtx_equal_p (subtarget, op0))
        !          3172:            subtarget = 0;
        !          3173: 
        !          3174:          tem = expand_unop (mode, neg_optab, op0, subtarget, 0);
        !          3175:          tem = expand_binop (mode, ior_optab, tem, op0, subtarget, 0,
        !          3176:                              OPTAB_WIDEN);
        !          3177: 
        !          3178:          if (tem && code == EQ)
        !          3179:            tem = expand_unop (mode, one_cmpl_optab, tem, subtarget, 0);
        !          3180:        }
        !          3181:     }
        !          3182: 
        !          3183:   if (tem && normalizep)
        !          3184:     tem = expand_shift (RSHIFT_EXPR, mode, tem,
        !          3185:                        size_int (GET_MODE_BITSIZE (mode) - 1),
        !          3186:                        tem, normalizep == 1);
        !          3187: 
        !          3188:   if (tem && GET_MODE (tem) != target_mode)
        !          3189:     {
        !          3190:       convert_move (target, tem, 0);
        !          3191:       tem = target;
        !          3192:     }
        !          3193: 
        !          3194:   if (tem == 0)
        !          3195:     delete_insns_since (last);
        !          3196: 
        !          3197:   return tem;
        !          3198: }

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