gcc/dojump.c

   1 /* Convert tree expression to rtl instructions, for GNU compiler.
   2    Copyright (C) 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
   3    2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to the Free
  19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  20 02111-1307, USA.  */
  21
  22 #include "config.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tm.h"
  26 #include "rtl.h"
  27 #include "tree.h"
  28 #include "flags.h"
  29 #include "function.h"
  30 #include "insn-config.h"
  31 #include "insn-attr.h"
  32 /* Include expr.h after insn-config.h so we get HAVE_conditional_move.  */
  33 #include "expr.h"
  34 #include "optabs.h"
  35 #include "langhooks.h"
  36 #include "ggc.h"
  37
  38 static bool prefer_and_bit_test (enum machine_mode, int);
  39 static void do_jump_by_parts_greater (tree, int, rtx, rtx);
  40 static void do_jump_by_parts_equality (tree, rtx, rtx);
  41 static void do_compare_and_jump (tree, enum rtx_code, enum rtx_code, rtx,
  42                                  rtx);
  43
  44 /* At the start of a function, record that we have no previously-pushed
  45    arguments waiting to be popped.  */
  46
  47 void
  48 init_pending_stack_adjust (void)
  49 {
  50   pending_stack_adjust = 0;
  51 }
  52
  53 /* When exiting from function, if safe, clear out any pending stack adjust
  54    so the adjustment won't get done.
  55
  56    Note, if the current function calls alloca, then it must have a
  57    frame pointer regardless of the value of flag_omit_frame_pointer.  */
  58
  59 void
  60 clear_pending_stack_adjust (void)
  61 {
  62   if (optimize > 0
  63       && (! flag_omit_frame_pointer || current_function_calls_alloca)
  64       && EXIT_IGNORE_STACK
  65       && ! (DECL_INLINE (current_function_decl) && ! flag_no_inline)
  66       && ! flag_inline_functions)
  67     {
  68       stack_pointer_delta -= pending_stack_adjust,
  69       pending_stack_adjust = 0;
  70     }
  71 }
  72
  73 /* Pop any previously-pushed arguments that have not been popped yet.  */
  74
  75 void
  76 do_pending_stack_adjust (void)
  77 {
  78   if (inhibit_defer_pop == 0)
  79     {
  80       if (pending_stack_adjust != 0)
  81         adjust_stack (GEN_INT (pending_stack_adjust));
  82       pending_stack_adjust = 0;
  83     }
  84 }
  85 \f
  86 /* Expand conditional expressions.  */
  87
  88 /* Generate code to evaluate EXP and jump to LABEL if the value is zero.
  89    LABEL is an rtx of code CODE_LABEL, in this function and all the
  90    functions here.  */
  91
  92 void
  93 jumpifnot (tree exp, rtx label)
  94 {
  95   do_jump (exp, label, NULL_RTX);
  96 }
  97
  98 /* Generate code to evaluate EXP and jump to LABEL if the value is nonzero.  */
  99
 100 void
 101 jumpif (tree exp, rtx label)
 102 {
 103   do_jump (exp, NULL_RTX, label);
 104 }
 105
 106 /* Used internally by prefer_and_bit_test.  */
 107
 108 static GTY(()) rtx and_reg;
 109 static GTY(()) rtx and_test;
 110 static GTY(()) rtx shift_test;
 111
 112 /* Compare the relative costs of "(X & (1 << BITNUM))" and "(X >> BITNUM) & 1",
 113    where X is an arbitrary register of mode MODE.  Return true if the former
 114    is preferred.  */
 115
 116 static bool
 117 prefer_and_bit_test (enum machine_mode mode, int bitnum)
 118 {
 119   if (and_test == 0)
 120     {
 121       /* Set up rtxes for the two variations.  Use NULL as a placeholder
 122          for the BITNUM-based constants.  */
 123       and_reg = gen_rtx_REG (mode, FIRST_PSEUDO_REGISTER);
 124       and_test = gen_rtx_AND (mode, and_reg, NULL);
 125       shift_test = gen_rtx_AND (mode, gen_rtx_ASHIFTRT (mode, and_reg, NULL),
 126                                 const1_rtx);
 127     }
 128   else
 129     {
 130       /* Change the mode of the previously-created rtxes.  */
 131       PUT_MODE (and_reg, mode);
 132       PUT_MODE (and_test, mode);
 133       PUT_MODE (shift_test, mode);
 134       PUT_MODE (XEXP (shift_test, 0), mode);
 135     }
 136
 137   /* Fill in the integers.  */
 138   XEXP (and_test, 1) = GEN_INT ((unsigned HOST_WIDE_INT) 1 << bitnum);
 139   XEXP (XEXP (shift_test, 0), 1) = GEN_INT (bitnum);
 140
 141   return (rtx_cost (and_test, IF_THEN_ELSE)
 142           <= rtx_cost (shift_test, IF_THEN_ELSE));
 143 }
 144
 145 /* Generate code to evaluate EXP and jump to IF_FALSE_LABEL if
 146    the result is zero, or IF_TRUE_LABEL if the result is one.
 147    Either of IF_FALSE_LABEL and IF_TRUE_LABEL may be zero,
 148    meaning fall through in that case.
 149
 150    do_jump always does any pending stack adjust except when it does not
 151    actually perform a jump.  An example where there is no jump
 152    is when EXP is `(foo (), 0)' and IF_FALSE_LABEL is null.
 153
 154    This function is responsible for optimizing cases such as
 155    &&, || and comparison operators in EXP.  */
 156
 157 void
 158 do_jump (tree exp, rtx if_false_label, rtx if_true_label)
 159 {
 160   enum tree_code code = TREE_CODE (exp);
 161   /* Some cases need to create a label to jump to
 162      in order to properly fall through.
 163      These cases set DROP_THROUGH_LABEL nonzero.  */
 164   rtx drop_through_label = 0;
 165   rtx temp;
 166   int i;
 167   tree type;
 168   enum machine_mode mode;
 169
 170   emit_queue ();
 171
 172   switch (code)
 173     {
 174     case ERROR_MARK:
 175       break;
 176
 177     case INTEGER_CST:
 178       temp = integer_zerop (exp) ? if_false_label : if_true_label;
 179       if (temp)
 180         emit_jump (temp);
 181       break;
 182
 183 #if 0
 184       /* This is not true with #pragma weak  */
 185     case ADDR_EXPR:
 186       /* The address of something can never be zero.  */
 187       if (if_true_label)
 188         emit_jump (if_true_label);
 189       break;
 190 #endif
 191
 192     case UNSAVE_EXPR:
 193       do_jump (TREE_OPERAND (exp, 0), if_false_label, if_true_label);
 194       TREE_OPERAND (exp, 0)
 195         = lang_hooks.unsave_expr_now (TREE_OPERAND (exp, 0));
 196       break;
 197
 198     case NOP_EXPR:
 199       if (TREE_CODE (TREE_OPERAND (exp, 0)) == COMPONENT_REF
 200           || TREE_CODE (TREE_OPERAND (exp, 0)) == BIT_FIELD_REF
 201           || TREE_CODE (TREE_OPERAND (exp, 0)) == ARRAY_REF
 202           || TREE_CODE (TREE_OPERAND (exp, 0)) == ARRAY_RANGE_REF)
 203         goto normal;
 204     case CONVERT_EXPR:
 205       /* If we are narrowing the operand, we have to do the compare in the
 206          narrower mode.  */
 207       if ((TYPE_PRECISION (TREE_TYPE (exp))
 208            < TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (exp, 0)))))
 209         goto normal;
 210     case NON_LVALUE_EXPR:
 211     case REFERENCE_EXPR:
 212     case ABS_EXPR:
 213     case NEGATE_EXPR:
 214     case LROTATE_EXPR:
 215     case RROTATE_EXPR:
 216       /* These cannot change zero->nonzero or vice versa.  */
 217       do_jump (TREE_OPERAND (exp, 0), if_false_label, if_true_label);
 218       break;
 219
 220 #if 0
 221       /* This is never less insns than evaluating the PLUS_EXPR followed by
 222          a test and can be longer if the test is eliminated.  */
 223     case PLUS_EXPR:
 224       /* Reduce to minus.  */
 225       exp = build (MINUS_EXPR, TREE_TYPE (exp),
 226                    TREE_OPERAND (exp, 0),
 227                    fold (build1 (NEGATE_EXPR, TREE_TYPE (TREE_OPERAND (exp, 1)),
 228                                  TREE_OPERAND (exp, 1))));
 229       /* Process as MINUS.  */
 230 #endif
 231
 232     case MINUS_EXPR:
 233       /* Nonzero iff operands of minus differ.  */
 234       do_compare_and_jump (build (NE_EXPR, TREE_TYPE (exp),
 235                                   TREE_OPERAND (exp, 0),
 236                                   TREE_OPERAND (exp, 1)),
 237                            NE, NE, if_false_label, if_true_label);
 238       break;
 239
 240     case BIT_AND_EXPR:
 241       /* fold_single_bit_test() converts (X & (1 << C)) into (X >> C) & 1.
 242          See if the former is preferred for jump tests and restore it
 243          if so.  */
 244       if (TREE_CODE (TREE_OPERAND (exp, 0)) == RSHIFT_EXPR
 245           && integer_onep (TREE_OPERAND (exp, 1)))
 246         {
 247           tree arg = TREE_OPERAND (TREE_OPERAND (exp, 0), 0);
 248           tree shift = TREE_OPERAND (TREE_OPERAND (exp, 0), 1);
 249           tree one = TREE_OPERAND (exp, 1);
 250           tree argtype = TREE_TYPE (arg);
 251           if (TREE_CODE (shift) == INTEGER_CST
 252               && compare_tree_int (shift, 0) > 0
 253               && compare_tree_int (shift, HOST_BITS_PER_WIDE_INT) < 0
 254               && prefer_and_bit_test (TYPE_MODE (argtype),
 255                                       TREE_INT_CST_LOW (shift)))
 256             {
 257               do_jump (build (BIT_AND_EXPR, argtype, arg,
 258                               fold (build (LSHIFT_EXPR, argtype, one, shift))),
 259                        if_false_label, if_true_label);
 260               break;
 261             }
 262         }
 263
 264       /* If we are AND'ing with a small constant, do this comparison in the
 265          smallest type that fits.  If the machine doesn't have comparisons
 266          that small, it will be converted back to the wider comparison.
 267          This helps if we are testing the sign bit of a narrower object.
 268          combine can't do this for us because it can't know whether a
 269          ZERO_EXTRACT or a compare in a smaller mode exists, but we do.  */
 270
 271       if (! SLOW_BYTE_ACCESS
 272           && TREE_CODE (TREE_OPERAND (exp, 1)) == INTEGER_CST
 273           && TYPE_PRECISION (TREE_TYPE (exp)) <= HOST_BITS_PER_WIDE_INT
 274           && (i = tree_floor_log2 (TREE_OPERAND (exp, 1))) >= 0
 275           && (mode = mode_for_size (i + 1, MODE_INT, 0)) != BLKmode
 276           && (type = lang_hooks.types.type_for_mode (mode, 1)) != 0
 277           && TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (exp))
 278           && (cmp_optab->handlers[(int) TYPE_MODE (type)].insn_code
 279               != CODE_FOR_nothing))
 280         {
 281           do_jump (convert (type, exp), if_false_label, if_true_label);
 282           break;
 283         }
 284       goto normal;
 285
 286     case TRUTH_NOT_EXPR:
 287       do_jump (TREE_OPERAND (exp, 0), if_true_label, if_false_label);
 288       break;
 289
 290     case TRUTH_ANDIF_EXPR:
 291       if (if_false_label == 0)
 292         if_false_label = drop_through_label = gen_label_rtx ();
 293       do_jump (TREE_OPERAND (exp, 0), if_false_label, NULL_RTX);
 294       start_cleanup_deferral ();
 295       do_jump (TREE_OPERAND (exp, 1), if_false_label, if_true_label);
 296       end_cleanup_deferral ();
 297       break;
 298
 299     case TRUTH_ORIF_EXPR:
 300       if (if_true_label == 0)
 301         if_true_label = drop_through_label = gen_label_rtx ();
 302       do_jump (TREE_OPERAND (exp, 0), NULL_RTX, if_true_label);
 303       start_cleanup_deferral ();
 304       do_jump (TREE_OPERAND (exp, 1), if_false_label, if_true_label);
 305       end_cleanup_deferral ();
 306       break;
 307
 308     case COMPOUND_EXPR:
 309       push_temp_slots ();
 310       expand_expr (TREE_OPERAND (exp, 0), const0_rtx, VOIDmode, 0);
 311       preserve_temp_slots (NULL_RTX);
 312       free_temp_slots ();
 313       pop_temp_slots ();
 314       emit_queue ();
 315       do_pending_stack_adjust ();
 316       do_jump (TREE_OPERAND (exp, 1), if_false_label, if_true_label);
 317       break;
 318
 319     case COMPONENT_REF:
 320     case BIT_FIELD_REF:
 321     case ARRAY_REF:
 322     case ARRAY_RANGE_REF:
 323       {
 324         HOST_WIDE_INT bitsize, bitpos;
 325         int unsignedp;
 326         enum machine_mode mode;
 327         tree type;
 328         tree offset;
 329         int volatilep = 0;
 330
 331         /* Get description of this reference.  We don't actually care
 332            about the underlying object here.  */
 333         get_inner_reference (exp, &bitsize, &bitpos, &offset, &mode,
 334                              &unsignedp, &volatilep);
 335
 336         type = lang_hooks.types.type_for_size (bitsize, unsignedp);
 337         if (! SLOW_BYTE_ACCESS
 338             && type != 0 && bitsize >= 0
 339             && TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (exp))
 340             && (cmp_optab->handlers[(int) TYPE_MODE (type)].insn_code
 341           != CODE_FOR_nothing))
 342           {
 343             do_jump (convert (type, exp), if_false_label, if_true_label);
 344             break;
 345           }
 346         goto normal;
 347       }
 348
 349     case COND_EXPR:
 350       /* Do (a ? 1 : 0) and (a ? 0 : 1) as special cases.  */
 351       if (integer_onep (TREE_OPERAND (exp, 1))
 352           && integer_zerop (TREE_OPERAND (exp, 2)))
 353         do_jump (TREE_OPERAND (exp, 0), if_false_label, if_true_label);
 354
 355       else if (integer_zerop (TREE_OPERAND (exp, 1))
 356                && integer_onep (TREE_OPERAND (exp, 2)))
 357         do_jump (TREE_OPERAND (exp, 0), if_true_label, if_false_label);
 358
 359       else
 360       {
 361         rtx label1 = gen_label_rtx ();
 362         drop_through_label = gen_label_rtx ();
 363
 364         do_jump (TREE_OPERAND (exp, 0), label1, NULL_RTX);
 365
 366         start_cleanup_deferral ();
 367         /* Now the THEN-expression.  */
 368         do_jump (TREE_OPERAND (exp, 1),
 369                  if_false_label ? if_false_label : drop_through_label,
 370                  if_true_label ? if_true_label : drop_through_label);
 371         /* In case the do_jump just above never jumps.  */
 372         do_pending_stack_adjust ();
 373         emit_label (label1);
 374
 375         /* Now the ELSE-expression.  */
 376         do_jump (TREE_OPERAND (exp, 2),
 377            if_false_label ? if_false_label : drop_through_label,
 378            if_true_label ? if_true_label : drop_through_label);
 379         end_cleanup_deferral ();
 380       }
 381       break;
 382
 383     case EQ_EXPR:
 384       {
 385         tree inner_type = TREE_TYPE (TREE_OPERAND (exp, 0));
 386
 387         if (GET_MODE_CLASS (TYPE_MODE (inner_type)) == MODE_COMPLEX_FLOAT
 388             || GET_MODE_CLASS (TYPE_MODE (inner_type)) == MODE_COMPLEX_INT)
 389           {
 390             tree exp0 = save_expr (TREE_OPERAND (exp, 0));
 391             tree exp1 = save_expr (TREE_OPERAND (exp, 1));
 392             do_jump
 393               (fold
 394                (build (TRUTH_ANDIF_EXPR, TREE_TYPE (exp),
 395                  fold (build (EQ_EXPR, TREE_TYPE (exp),
 396                   fold (build1 (REALPART_EXPR,
 397                     TREE_TYPE (inner_type),
 398                     exp0)),
 399                   fold (build1 (REALPART_EXPR,
 400                     TREE_TYPE (inner_type),
 401                     exp1)))),
 402                  fold (build (EQ_EXPR, TREE_TYPE (exp),
 403                   fold (build1 (IMAGPART_EXPR,
 404                     TREE_TYPE (inner_type),
 405                     exp0)),
 406                   fold (build1 (IMAGPART_EXPR,
 407                     TREE_TYPE (inner_type),
 408                     exp1)))))),
 409                if_false_label, if_true_label);
 410           }
 411
 412         else if (integer_zerop (TREE_OPERAND (exp, 1)))
 413           do_jump (TREE_OPERAND (exp, 0), if_true_label, if_false_label);
 414
 415         else if (GET_MODE_CLASS (TYPE_MODE (inner_type)) == MODE_INT
 416                  && !can_compare_p (EQ, TYPE_MODE (inner_type), ccp_jump))
 417           do_jump_by_parts_equality (exp, if_false_label, if_true_label);
 418         else
 419           do_compare_and_jump (exp, EQ, EQ, if_false_label, if_true_label);
 420         break;
 421       }
 422
 423     case NE_EXPR:
 424       {
 425         tree inner_type = TREE_TYPE (TREE_OPERAND (exp, 0));
 426
 427         if (GET_MODE_CLASS (TYPE_MODE (inner_type)) == MODE_COMPLEX_FLOAT
 428             || GET_MODE_CLASS (TYPE_MODE (inner_type)) == MODE_COMPLEX_INT)
 429           {
 430             tree exp0 = save_expr (TREE_OPERAND (exp, 0));
 431             tree exp1 = save_expr (TREE_OPERAND (exp, 1));
 432             do_jump
 433               (fold
 434                (build (TRUTH_ORIF_EXPR, TREE_TYPE (exp),
 435                  fold (build (NE_EXPR, TREE_TYPE (exp),
 436                   fold (build1 (REALPART_EXPR,
 437                     TREE_TYPE (inner_type),
 438                     exp0)),
 439                   fold (build1 (REALPART_EXPR,
 440                     TREE_TYPE (inner_type),
 441                     exp1)))),
 442                  fold (build (NE_EXPR, TREE_TYPE (exp),
 443                     fold (build1 (IMAGPART_EXPR,
 444                       TREE_TYPE (inner_type),
 445                       exp0)),
 446                     fold (build1 (IMAGPART_EXPR,
 447                       TREE_TYPE (inner_type),
 448                       exp1)))))),
 449                if_false_label, if_true_label);
 450           }
 451
 452         else if (integer_zerop (TREE_OPERAND (exp, 1)))
 453           do_jump (TREE_OPERAND (exp, 0), if_false_label, if_true_label);
 454
 455         else if (GET_MODE_CLASS (TYPE_MODE (inner_type)) == MODE_INT
 456            && !can_compare_p (NE, TYPE_MODE (inner_type), ccp_jump))
 457           do_jump_by_parts_equality (exp, if_true_label, if_false_label);
 458         else
 459           do_compare_and_jump (exp, NE, NE, if_false_label, if_true_label);
 460         break;
 461       }
 462
 463     case LT_EXPR:
 464       mode = TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)));
 465       if (GET_MODE_CLASS (mode) == MODE_INT
 466           && ! can_compare_p (LT, mode, ccp_jump))
 467         do_jump_by_parts_greater (exp, 1, if_false_label, if_true_label);
 468       else
 469         do_compare_and_jump (exp, LT, LTU, if_false_label, if_true_label);
 470       break;
 471
 472     case LE_EXPR:
 473       mode = TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)));
 474       if (GET_MODE_CLASS (mode) == MODE_INT
 475           && ! can_compare_p (LE, mode, ccp_jump))
 476         do_jump_by_parts_greater (exp, 0, if_true_label, if_false_label);
 477       else
 478         do_compare_and_jump (exp, LE, LEU, if_false_label, if_true_label);
 479       break;
 480
 481     case GT_EXPR:
 482       mode = TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)));
 483       if (GET_MODE_CLASS (mode) == MODE_INT
 484           && ! can_compare_p (GT, mode, ccp_jump))
 485         do_jump_by_parts_greater (exp, 0, if_false_label, if_true_label);
 486       else
 487         do_compare_and_jump (exp, GT, GTU, if_false_label, if_true_label);
 488       break;
 489
 490     case GE_EXPR:
 491       mode = TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)));
 492       if (GET_MODE_CLASS (mode) == MODE_INT
 493           && ! can_compare_p (GE, mode, ccp_jump))
 494         do_jump_by_parts_greater (exp, 1, if_true_label, if_false_label);
 495       else
 496         do_compare_and_jump (exp, GE, GEU, if_false_label, if_true_label);
 497       break;
 498
 499     case UNORDERED_EXPR:
 500     case ORDERED_EXPR:
 501       {
 502         enum rtx_code cmp, rcmp;
 503         int do_rev;
 504
 505         if (code == UNORDERED_EXPR)
 506           cmp = UNORDERED, rcmp = ORDERED;
 507         else
 508           cmp = ORDERED, rcmp = UNORDERED;
 509         mode = TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)));
 510
 511         do_rev = 0;
 512         if (! can_compare_p (cmp, mode, ccp_jump)
 513             && (can_compare_p (rcmp, mode, ccp_jump)
 514           /* If the target doesn't provide either UNORDERED or ORDERED
 515              comparisons, canonicalize on UNORDERED for the library.  */
 516           || rcmp == UNORDERED))
 517           do_rev = 1;
 518
 519         if (! do_rev)
 520           do_compare_and_jump (exp, cmp, cmp, if_false_label, if_true_label);
 521         else
 522           do_compare_and_jump (exp, rcmp, rcmp, if_true_label, if_false_label);
 523       }
 524       break;
 525
 526     {
 527       enum rtx_code rcode1;
 528       enum tree_code tcode2;
 529
 530       case UNLT_EXPR:
 531         rcode1 = UNLT;
 532         tcode2 = LT_EXPR;
 533         goto unordered_bcc;
 534       case UNLE_EXPR:
 535         rcode1 = UNLE;
 536         tcode2 = LE_EXPR;
 537         goto unordered_bcc;
 538       case UNGT_EXPR:
 539         rcode1 = UNGT;
 540         tcode2 = GT_EXPR;
 541         goto unordered_bcc;
 542       case UNGE_EXPR:
 543         rcode1 = UNGE;
 544         tcode2 = GE_EXPR;
 545         goto unordered_bcc;
 546       case UNEQ_EXPR:
 547         rcode1 = UNEQ;
 548         tcode2 = EQ_EXPR;
 549         goto unordered_bcc;
 550
 551       unordered_bcc:
 552         mode = TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)));
 553         if (can_compare_p (rcode1, mode, ccp_jump))
 554           do_compare_and_jump (exp, rcode1, rcode1, if_false_label,
 555                                if_true_label);
 556         else
 557           {
 558             tree op0 = save_expr (TREE_OPERAND (exp, 0));
 559             tree op1 = save_expr (TREE_OPERAND (exp, 1));
 560             tree cmp0, cmp1;
 561
 562             /* If the target doesn't support combined unordered
 563                compares, decompose into UNORDERED + comparison.  */
 564             cmp0 = fold (build (UNORDERED_EXPR, TREE_TYPE (exp), op0, op1));
 565             cmp1 = fold (build (tcode2, TREE_TYPE (exp), op0, op1));
 566             exp = build (TRUTH_ORIF_EXPR, TREE_TYPE (exp), cmp0, cmp1);
 567             do_jump (exp, if_false_label, if_true_label);
 568           }
 569       }
 570       break;
 571
 572       /* Special case:
 573           __builtin_expect (<test>, 0)  and
 574           __builtin_expect (<test>, 1)
 575
 576          We need to do this here, so that <test> is not converted to a SCC
 577          operation on machines that use condition code registers and COMPARE
 578          like the PowerPC, and then the jump is done based on whether the SCC
 579          operation produced a 1 or 0.  */
 580     case CALL_EXPR:
 581       /* Check for a built-in function.  */
 582       {
 583         tree fndecl = get_callee_fndecl (exp);
 584         tree arglist = TREE_OPERAND (exp, 1);
 585
 586         if (fndecl
 587             && DECL_BUILT_IN (fndecl)
 588             && DECL_FUNCTION_CODE (fndecl) == BUILT_IN_EXPECT
 589             && arglist != NULL_TREE
 590             && TREE_CHAIN (arglist) != NULL_TREE)
 591           {
 592             rtx seq = expand_builtin_expect_jump (exp, if_false_label,
 593                                                   if_true_label);
 594
 595             if (seq != NULL_RTX)
 596               {
 597                 emit_insn (seq);
 598                 return;
 599               }
 600           }
 601       }
 602       /* Fall through and generate the normal code.  */
 603
 604     default:
 605     normal:
 606       temp = expand_expr (exp, NULL_RTX, VOIDmode, 0);
 607 #if 0
 608       /* This is not needed any more and causes poor code since it causes
 609          comparisons and tests from non-SI objects to have different code
 610          sequences.  */
 611       /* Copy to register to avoid generating bad insns by cse
 612          from (set (mem ...) (arithop))  (set (cc0) (mem ...)).  */
 613       if (!cse_not_expected && GET_CODE (temp) == MEM)
 614         temp = copy_to_reg (temp);
 615 #endif
 616       do_pending_stack_adjust ();
 617       /* Do any postincrements in the expression that was tested.  */
 618       emit_queue ();
 619
 620       if (GET_CODE (temp) == CONST_INT
 621           || (GET_CODE (temp) == CONST_DOUBLE && GET_MODE (temp) == VOIDmode)
 622           || GET_CODE (temp) == LABEL_REF)
 623         {
 624           rtx target = temp == const0_rtx ? if_false_label : if_true_label;
 625           if (target)
 626             emit_jump (target);
 627         }
 628       else if (GET_MODE_CLASS (GET_MODE (temp)) == MODE_INT
 629                && ! can_compare_p (NE, GET_MODE (temp), ccp_jump))
 630         /* Note swapping the labels gives us not-equal.  */
 631         do_jump_by_parts_equality_rtx (temp, if_true_label, if_false_label);
 632       else if (GET_MODE (temp) != VOIDmode)
 633         {
 634           /* The RTL optimizers prefer comparisons against pseudos.  */
 635           if (GET_CODE (temp) == SUBREG)
 636             {
 637               /* Compare promoted variables in their promoted mode.  */
 638               if (SUBREG_PROMOTED_VAR_P (temp)
 639                   && GET_CODE (XEXP (temp, 0)) == REG)
 640                 temp = XEXP (temp, 0);
 641               else
 642                 temp = copy_to_reg (temp);
 643             }
 644           do_compare_rtx_and_jump (temp, CONST0_RTX (GET_MODE (temp)),
 645                                    NE, TYPE_UNSIGNED (TREE_TYPE (exp)),
 646                                    GET_MODE (temp), NULL_RTX,
 647                                    if_false_label, if_true_label);
 648         }
 649       else
 650         abort ();
 651     }
 652
 653   if (drop_through_label)
 654     {
 655       /* If do_jump produces code that might be jumped around,
 656          do any stack adjusts from that code, before the place
 657          where control merges in.  */
 658       do_pending_stack_adjust ();
 659       emit_label (drop_through_label);
 660     }
 661 }
 662 \f
 663 /* Given a comparison expression EXP for values too wide to be compared
 664    with one insn, test the comparison and jump to the appropriate label.
 665    The code of EXP is ignored; we always test GT if SWAP is 0,
 666    and LT if SWAP is 1.  */
 667
 668 static void
 669 do_jump_by_parts_greater (tree exp, int swap, rtx if_false_label,
 670                           rtx if_true_label)
 671 {
 672   rtx op0 = expand_expr (TREE_OPERAND (exp, swap), NULL_RTX, VOIDmode, 0);
 673   rtx op1 = expand_expr (TREE_OPERAND (exp, !swap), NULL_RTX, VOIDmode, 0);
 674   enum machine_mode mode = TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)));
 675   int unsignedp = TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (exp, 0)));
 676
 677   do_jump_by_parts_greater_rtx (mode, unsignedp, op0, op1, if_false_label,
 678                                 if_true_label);
 679 }
 680
 681 /* Compare OP0 with OP1, word at a time, in mode MODE.
 682    UNSIGNEDP says to do unsigned comparison.
 683    Jump to IF_TRUE_LABEL if OP0 is greater, IF_FALSE_LABEL otherwise.  */
 684
 685 void
 686 do_jump_by_parts_greater_rtx (enum machine_mode mode, int unsignedp, rtx op0,
 687                               rtx op1, rtx if_false_label, rtx if_true_label)
 688 {
 689   int nwords = (GET_MODE_SIZE (mode) / UNITS_PER_WORD);
 690   rtx drop_through_label = 0;
 691   int i;
 692
 693   if (! if_true_label || ! if_false_label)
 694     drop_through_label = gen_label_rtx ();
 695   if (! if_true_label)
 696     if_true_label = drop_through_label;
 697   if (! if_false_label)
 698     if_false_label = drop_through_label;
 699
 700   /* Compare a word at a time, high order first.  */
 701   for (i = 0; i < nwords; i++)
 702     {
 703       rtx op0_word, op1_word;
 704
 705       if (WORDS_BIG_ENDIAN)
 706         {
 707           op0_word = operand_subword_force (op0, i, mode);
 708           op1_word = operand_subword_force (op1, i, mode);
 709         }
 710       else
 711         {
 712           op0_word = operand_subword_force (op0, nwords - 1 - i, mode);
 713           op1_word = operand_subword_force (op1, nwords - 1 - i, mode);
 714         }
 715
 716       /* All but high-order word must be compared as unsigned.  */
 717       do_compare_rtx_and_jump (op0_word, op1_word, GT,
 718                                (unsignedp || i > 0), word_mode, NULL_RTX,
 719                                NULL_RTX, if_true_label);
 720
 721       /* Consider lower words only if these are equal.  */
 722       do_compare_rtx_and_jump (op0_word, op1_word, NE, unsignedp, word_mode,
 723                                NULL_RTX, NULL_RTX, if_false_label);
 724     }
 725
 726   if (if_false_label)
 727     emit_jump (if_false_label);
 728   if (drop_through_label)
 729     emit_label (drop_through_label);
 730 }
 731
 732 /* Given an EQ_EXPR expression EXP for values too wide to be compared
 733    with one insn, test the comparison and jump to the appropriate label.  */
 734
 735 static void
 736 do_jump_by_parts_equality (tree exp, rtx if_false_label, rtx if_true_label)
 737 {
 738   rtx op0 = expand_expr (TREE_OPERAND (exp, 0), NULL_RTX, VOIDmode, 0);
 739   rtx op1 = expand_expr (TREE_OPERAND (exp, 1), NULL_RTX, VOIDmode, 0);
 740   enum machine_mode mode = TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp, 0)));
 741   int nwords = (GET_MODE_SIZE (mode) / UNITS_PER_WORD);
 742   int i;
 743   rtx drop_through_label = 0;
 744
 745   if (! if_false_label)
 746     drop_through_label = if_false_label = gen_label_rtx ();
 747
 748   for (i = 0; i < nwords; i++)
 749     do_compare_rtx_and_jump (operand_subword_force (op0, i, mode),
 750                              operand_subword_force (op1, i, mode),
 751                              EQ, TYPE_UNSIGNED (TREE_TYPE (exp)),
 752                              word_mode, NULL_RTX, if_false_label, NULL_RTX);
 753
 754   if (if_true_label)
 755     emit_jump (if_true_label);
 756   if (drop_through_label)
 757     emit_label (drop_through_label);
 758 }
 759 \f
 760 /* Jump according to whether OP0 is 0.
 761    We assume that OP0 has an integer mode that is too wide
 762    for the available compare insns.  */
 763
 764 void
 765 do_jump_by_parts_equality_rtx (rtx op0, rtx if_false_label, rtx if_true_label)
 766 {
 767   int nwords = GET_MODE_SIZE (GET_MODE (op0)) / UNITS_PER_WORD;
 768   rtx part;
 769   int i;
 770   rtx drop_through_label = 0;
 771
 772   /* The fastest way of doing this comparison on almost any machine is to
 773      "or" all the words and compare the result.  If all have to be loaded
 774      from memory and this is a very wide item, it's possible this may
 775      be slower, but that's highly unlikely.  */
 776
 777   part = gen_reg_rtx (word_mode);
 778   emit_move_insn (part, operand_subword_force (op0, 0, GET_MODE (op0)));
 779   for (i = 1; i < nwords && part != 0; i++)
 780     part = expand_binop (word_mode, ior_optab, part,
 781                          operand_subword_force (op0, i, GET_MODE (op0)),
 782                          part, 1, OPTAB_WIDEN);
 783
 784   if (part != 0)
 785     {
 786       do_compare_rtx_and_jump (part, const0_rtx, EQ, 1, word_mode,
 787                                NULL_RTX, if_false_label, if_true_label);
 788
 789       return;
 790     }
 791
 792   /* If we couldn't do the "or" simply, do this with a series of compares.  */
 793   if (! if_false_label)
 794     drop_through_label = if_false_label = gen_label_rtx ();
 795
 796   for (i = 0; i < nwords; i++)
 797     do_compare_rtx_and_jump (operand_subword_force (op0, i, GET_MODE (op0)),
 798                              const0_rtx, EQ, 1, word_mode, NULL_RTX,
 799                              if_false_label, NULL_RTX);
 800
 801   if (if_true_label)
 802     emit_jump (if_true_label);
 803
 804   if (drop_through_label)
 805     emit_label (drop_through_label);
 806 }
 807 \f
 808 /* Generate code for a comparison of OP0 and OP1 with rtx code CODE.
 809    (including code to compute the values to be compared)
 810    and set (CC0) according to the result.
 811    The decision as to signed or unsigned comparison must be made by the caller.
 812
 813    We force a stack adjustment unless there are currently
 814    things pushed on the stack that aren't yet used.
 815
 816    If MODE is BLKmode, SIZE is an RTX giving the size of the objects being
 817    compared.  */
 818
 819 rtx
 820 compare_from_rtx (rtx op0, rtx op1, enum rtx_code code, int unsignedp,
 821                   enum machine_mode mode, rtx size)
 822 {
 823   rtx tem;
 824
 825   /* If one operand is constant, make it the second one.  Only do this
 826      if the other operand is not constant as well.  */
 827
 828   if (swap_commutative_operands_p (op0, op1))
 829     {
 830       tem = op0;
 831       op0 = op1;
 832       op1 = tem;
 833       code = swap_condition (code);
 834     }
 835
 836   if (flag_force_mem)
 837     {
 838       op0 = force_not_mem (op0);
 839       op1 = force_not_mem (op1);
 840     }
 841
 842   do_pending_stack_adjust ();
 843
 844   code = unsignedp ? unsigned_condition (code) : code;
 845   if (0 != (tem = simplify_relational_operation (code, mode, VOIDmode,
 846                                                  op0, op1)))
 847     {
 848       if (CONSTANT_P (tem))
 849         return tem;
 850
 851       code = GET_CODE (tem);
 852       mode = GET_MODE (tem);
 853       op0 = XEXP (tem, 0);
 854       op1 = XEXP (tem, 1);
 855       unsignedp = (code == GTU || code == LTU || code == GEU || code == LEU);
 856     }
 857
 858   emit_cmp_insn (op0, op1, code, size, mode, unsignedp);
 859
 860 #if HAVE_cc0
 861   return gen_rtx_fmt_ee (code, VOIDmode, cc0_rtx, const0_rtx);
 862 #else
 863   return gen_rtx_fmt_ee (code, VOIDmode, op0, op1);
 864 #endif
 865 }
 866
 867 /* Like do_compare_and_jump but expects the values to compare as two rtx's.
 868    The decision as to signed or unsigned comparison must be made by the caller.
 869
 870    If MODE is BLKmode, SIZE is an RTX giving the size of the objects being
 871    compared.  */
 872
 873 void
 874 do_compare_rtx_and_jump (rtx op0, rtx op1, enum rtx_code code, int unsignedp,
 875                          enum machine_mode mode, rtx size, rtx if_false_label,
 876                          rtx if_true_label)
 877 {
 878   rtx tem;
 879   int dummy_true_label = 0;
 880
 881   /* Reverse the comparison if that is safe and we want to jump if it is
 882      false.  */
 883   if (! if_true_label && ! FLOAT_MODE_P (mode))
 884     {
 885       if_true_label = if_false_label;
 886       if_false_label = 0;
 887       code = reverse_condition (code);
 888     }
 889
 890   /* If one operand is constant, make it the second one.  Only do this
 891      if the other operand is not constant as well.  */
 892
 893   if (swap_commutative_operands_p (op0, op1))
 894     {
 895       tem = op0;
 896       op0 = op1;
 897       op1 = tem;
 898       code = swap_condition (code);
 899     }
 900
 901   if (flag_force_mem)
 902     {
 903       op0 = force_not_mem (op0);
 904       op1 = force_not_mem (op1);
 905     }
 906
 907   do_pending_stack_adjust ();
 908
 909   code = unsignedp ? unsigned_condition (code) : code;
 910   if (0 != (tem = simplify_relational_operation (code, mode, VOIDmode,
 911                                                  op0, op1)))
 912     {
 913       if (CONSTANT_P (tem))
 914         {
 915           rtx label = (tem == const0_rtx || tem == CONST0_RTX (mode))
 916                       ? if_false_label : if_true_label;
 917           if (label)
 918             emit_jump (label);
 919           return;
 920         }
 921
 922       code = GET_CODE (tem);
 923       mode = GET_MODE (tem);
 924       op0 = XEXP (tem, 0);
 925       op1 = XEXP (tem, 1);
 926       unsignedp = (code == GTU || code == LTU || code == GEU || code == LEU);
 927     }
 928
 929   if (! if_true_label)
 930     {
 931       dummy_true_label = 1;
 932       if_true_label = gen_label_rtx ();
 933     }
 934
 935   emit_cmp_and_jump_insns (op0, op1, code, size, mode, unsignedp,
 936                            if_true_label);
 937
 938   if (if_false_label)
 939     emit_jump (if_false_label);
 940   if (dummy_true_label)
 941     emit_label (if_true_label);
 942 }
 943
 944 /* Generate code for a comparison expression EXP (including code to compute
 945    the values to be compared) and a conditional jump to IF_FALSE_LABEL and/or
 946    IF_TRUE_LABEL.  One of the labels can be NULL_RTX, in which case the
 947    generated code will drop through.
 948    SIGNED_CODE should be the rtx operation for this comparison for
 949    signed data; UNSIGNED_CODE, likewise for use if data is unsigned.
 950
 951    We force a stack adjustment unless there are currently
 952    things pushed on the stack that aren't yet used.  */
 953
 954 static void
 955 do_compare_and_jump (tree exp, enum rtx_code signed_code,
 956                      enum rtx_code unsigned_code, rtx if_false_label,
 957                      rtx if_true_label)
 958 {
 959   rtx op0, op1;
 960   tree type;
 961   enum machine_mode mode;
 962   int unsignedp;
 963   enum rtx_code code;
 964
 965   /* Don't crash if the comparison was erroneous.  */
 966   op0 = expand_expr (TREE_OPERAND (exp, 0), NULL_RTX, VOIDmode, 0);
 967   if (TREE_CODE (TREE_OPERAND (exp, 0)) == ERROR_MARK)
 968     return;
 969
 970   op1 = expand_expr (TREE_OPERAND (exp, 1), NULL_RTX, VOIDmode, 0);
 971   if (TREE_CODE (TREE_OPERAND (exp, 1)) == ERROR_MARK)
 972     return;
 973
 974   type = TREE_TYPE (TREE_OPERAND (exp, 0));
 975   mode = TYPE_MODE (type);
 976   if (TREE_CODE (TREE_OPERAND (exp, 0)) == INTEGER_CST
 977       && (TREE_CODE (TREE_OPERAND (exp, 1)) != INTEGER_CST
 978           || (GET_MODE_BITSIZE (mode)
 979               > GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (TREE_OPERAND (exp,
 980                                                                       1)))))))
 981     {
 982       /* op0 might have been replaced by promoted constant, in which
 983          case the type of second argument should be used.  */
 984       type = TREE_TYPE (TREE_OPERAND (exp, 1));
 985       mode = TYPE_MODE (type);
 986     }
 987   unsignedp = TYPE_UNSIGNED (type);
 988   code = unsignedp ? unsigned_code : signed_code;
 989
 990 #ifdef HAVE_canonicalize_funcptr_for_compare
 991   /* If function pointers need to be "canonicalized" before they can
 992      be reliably compared, then canonicalize them.  */
 993   if (HAVE_canonicalize_funcptr_for_compare
 994       && TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == POINTER_TYPE
 995       && (TREE_CODE (TREE_TYPE (TREE_TYPE (TREE_OPERAND (exp, 0))))
 996           == FUNCTION_TYPE))
 997     {
 998       rtx new_op0 = gen_reg_rtx (mode);
 999
1000       emit_insn (gen_canonicalize_funcptr_for_compare (new_op0, op0));
1001       op0 = new_op0;
1002     }
1003
1004   if (HAVE_canonicalize_funcptr_for_compare
1005       && TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 1))) == POINTER_TYPE
1006       && (TREE_CODE (TREE_TYPE (TREE_TYPE (TREE_OPERAND (exp, 1))))
1007           == FUNCTION_TYPE))
1008     {
1009       rtx new_op1 = gen_reg_rtx (mode);
1010
1011       emit_insn (gen_canonicalize_funcptr_for_compare (new_op1, op1));
1012       op1 = new_op1;
1013     }
1014 #endif
1015
1016   /* Do any postincrements in the expression that was tested.  */
1017   emit_queue ();
1018
1019   do_compare_rtx_and_jump (op0, op1, code, unsignedp, mode,
1020                            ((mode == BLKmode)
1021                             ? expr_size (TREE_OPERAND (exp, 0)) : NULL_RTX),
1022                            if_false_label, if_true_label);
1023 }
1024
1025 #include "gt-dojump.h"