gcc/convert.c

   1 /* Utility routines for data type conversion for GCC.
   2    Copyright (C) 1987, 1988, 1991, 1992, 1993, 1994, 1995, 1997, 1998,
   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
  23 /* These routines are somewhat language-independent utility function
  24    intended to be called by the language-specific convert () functions.  */
  25
  26 #include "config.h"
  27 #include "system.h"
  28 #include "coretypes.h"
  29 #include "tm.h"
  30 #include "tree.h"
  31 #include "flags.h"
  32 #include "convert.h"
  33 #include "toplev.h"
  34 #include "langhooks.h"
  35 #include "real.h"
  36 /* Convert EXPR to some pointer or reference type TYPE.
  37
  38    EXPR must be pointer, reference, integer, enumeral, or literal zero;
  39    in other cases error is called.  */
  40
  41 tree
  42 convert_to_pointer (tree type, tree expr)
  43 {
  44   if (integer_zerop (expr))
  45     {
  46       expr = build_int_cst (type, 0);
  47       return expr;
  48     }
  49
  50   switch (TREE_CODE (TREE_TYPE (expr)))
  51     {
  52     case POINTER_TYPE:
  53     case REFERENCE_TYPE:
  54       return build1 (NOP_EXPR, type, expr);
  55
  56     case INTEGER_TYPE:
  57     case ENUMERAL_TYPE:
  58     case BOOLEAN_TYPE:
  59     case CHAR_TYPE:
  60       if (TYPE_PRECISION (TREE_TYPE (expr)) == POINTER_SIZE)
  61         return build1 (CONVERT_EXPR, type, expr);
  62
  63       return
  64         convert_to_pointer (type,
  65                             convert (lang_hooks.types.type_for_size
  66                                      (POINTER_SIZE, 0), expr));
  67
  68     default:
  69       error ("cannot convert to a pointer type");
  70       return convert_to_pointer (type, integer_zero_node);
  71     }
  72 }
  73
  74 /* Avoid any floating point extensions from EXP.  */
  75 tree
  76 strip_float_extensions (tree exp)
  77 {
  78   tree sub, expt, subt;
  79
  80   /*  For floating point constant look up the narrowest type that can hold
  81       it properly and handle it like (type)(narrowest_type)constant.
  82       This way we can optimize for instance a=a*2.0 where "a" is float
  83       but 2.0 is double constant.  */
  84   if (TREE_CODE (exp) == REAL_CST)
  85     {
  86       REAL_VALUE_TYPE orig;
  87       tree type = NULL;
  88
  89       orig = TREE_REAL_CST (exp);
  90       if (TYPE_PRECISION (TREE_TYPE (exp)) > TYPE_PRECISION (float_type_node)
  91           && exact_real_truncate (TYPE_MODE (float_type_node), &orig))
  92         type = float_type_node;
  93       else if (TYPE_PRECISION (TREE_TYPE (exp))
  94                > TYPE_PRECISION (double_type_node)
  95                && exact_real_truncate (TYPE_MODE (double_type_node), &orig))
  96         type = double_type_node;
  97       if (type)
  98         return build_real (type, real_value_truncate (TYPE_MODE (type), orig));
  99     }
 100
 101   if (TREE_CODE (exp) != NOP_EXPR
 102       && TREE_CODE (exp) != CONVERT_EXPR)
 103     return exp;
 104
 105   sub = TREE_OPERAND (exp, 0);
 106   subt = TREE_TYPE (sub);
 107   expt = TREE_TYPE (exp);
 108
 109   if (!FLOAT_TYPE_P (subt))
 110     return exp;
 111
 112   if (TYPE_PRECISION (subt) > TYPE_PRECISION (expt))
 113     return exp;
 114
 115   return strip_float_extensions (sub);
 116 }
 117
 118
 119 /* Convert EXPR to some floating-point type TYPE.
 120
 121    EXPR must be float, integer, or enumeral;
 122    in other cases error is called.  */
 123
 124 tree
 125 convert_to_real (tree type, tree expr)
 126 {
 127   enum built_in_function fcode = builtin_mathfn_code (expr);
 128   tree itype = TREE_TYPE (expr);
 129
 130   /* Disable until we figure out how to decide whether the functions are
 131      present in runtime.  */
 132   /* Convert (float)sqrt((double)x) where x is float into sqrtf(x) */
 133   if (optimize
 134       && (TYPE_MODE (type) == TYPE_MODE (double_type_node)
 135           || TYPE_MODE (type) == TYPE_MODE (float_type_node)))
 136     {
 137       switch (fcode)
 138         {
 139 #define CASE_MATHFN(FN) case BUILT_IN_##FN: case BUILT_IN_##FN##L:
 140           CASE_MATHFN (ACOS)
 141           CASE_MATHFN (ACOSH)
 142           CASE_MATHFN (ASIN)
 143           CASE_MATHFN (ASINH)
 144           CASE_MATHFN (ATAN)
 145           CASE_MATHFN (ATANH)
 146           CASE_MATHFN (CBRT)
 147           CASE_MATHFN (COS)
 148           CASE_MATHFN (COSH)
 149           CASE_MATHFN (ERF)
 150           CASE_MATHFN (ERFC)
 151           CASE_MATHFN (EXP)
 152           CASE_MATHFN (EXP10)
 153           CASE_MATHFN (EXP2)
 154           CASE_MATHFN (EXPM1)
 155           CASE_MATHFN (FABS)
 156           CASE_MATHFN (GAMMA)
 157           CASE_MATHFN (J0)
 158           CASE_MATHFN (J1)
 159           CASE_MATHFN (LGAMMA)
 160           CASE_MATHFN (LOG)
 161           CASE_MATHFN (LOG10)
 162           CASE_MATHFN (LOG1P)
 163           CASE_MATHFN (LOG2)
 164           CASE_MATHFN (LOGB)
 165           CASE_MATHFN (POW10)
 166           CASE_MATHFN (SIN)
 167           CASE_MATHFN (SINH)
 168           CASE_MATHFN (SQRT)
 169           CASE_MATHFN (TAN)
 170           CASE_MATHFN (TANH)
 171           CASE_MATHFN (TGAMMA)
 172           CASE_MATHFN (Y0)
 173           CASE_MATHFN (Y1)
 174 #undef CASE_MATHFN
 175             {
 176               tree arg0 = strip_float_extensions (TREE_VALUE (TREE_OPERAND (expr, 1)));
 177               tree newtype = type;
 178
 179               /* We have (outertype)sqrt((innertype)x).  Choose the wider mode from
 180                  the both as the safe type for operation.  */
 181               if (TYPE_PRECISION (TREE_TYPE (arg0)) > TYPE_PRECISION (type))
 182                 newtype = TREE_TYPE (arg0);
 183
 184               /* Be careful about integer to fp conversions.
 185                  These may overflow still.  */
 186               if (FLOAT_TYPE_P (TREE_TYPE (arg0))
 187                   && TYPE_PRECISION (newtype) < TYPE_PRECISION (itype)
 188                   && (TYPE_MODE (newtype) == TYPE_MODE (double_type_node)
 189                       || TYPE_MODE (newtype) == TYPE_MODE (float_type_node)))
 190                 {
 191                   tree arglist;
 192                   tree fn = mathfn_built_in (newtype, fcode);
 193
 194                   if (fn)
 195                   {
 196                     arglist = build_tree_list (NULL_TREE, fold (convert_to_real (newtype, arg0)));
 197                     expr = build_function_call_expr (fn, arglist);
 198                     if (newtype == type)
 199                       return expr;
 200                   }
 201                 }
 202             }
 203         default:
 204           break;
 205         }
 206     }
 207   if (optimize
 208       && (((fcode == BUILT_IN_FLOORL
 209            || fcode == BUILT_IN_CEILL
 210            || fcode == BUILT_IN_ROUNDL
 211            || fcode == BUILT_IN_RINTL
 212            || fcode == BUILT_IN_TRUNCL
 213            || fcode == BUILT_IN_NEARBYINTL)
 214           && (TYPE_MODE (type) == TYPE_MODE (double_type_node)
 215               || TYPE_MODE (type) == TYPE_MODE (float_type_node)))
 216           || ((fcode == BUILT_IN_FLOOR
 217                || fcode == BUILT_IN_CEIL
 218                || fcode == BUILT_IN_ROUND
 219                || fcode == BUILT_IN_RINT
 220                || fcode == BUILT_IN_TRUNC
 221                || fcode == BUILT_IN_NEARBYINT)
 222               && (TYPE_MODE (type) == TYPE_MODE (float_type_node)))))
 223     {
 224       tree fn = mathfn_built_in (type, fcode);
 225
 226       if (fn)
 227         {
 228           tree arg0 = strip_float_extensions (TREE_VALUE (TREE_OPERAND (expr,
 229                                                                         1)));
 230           tree arglist = build_tree_list (NULL_TREE,
 231                                           fold (convert_to_real (type, arg0)));
 232
 233           return build_function_call_expr (fn, arglist);
 234         }
 235     }
 236
 237   /* Propagate the cast into the operation.  */
 238   if (itype != type && FLOAT_TYPE_P (type))
 239     switch (TREE_CODE (expr))
 240       {
 241         /* Convert (float)-x into -(float)x.  This is always safe.  */
 242         case ABS_EXPR:
 243         case NEGATE_EXPR:
 244           if (TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (expr)))
 245             return build1 (TREE_CODE (expr), type,
 246                            fold (convert_to_real (type,
 247                                                   TREE_OPERAND (expr, 0))));
 248           break;
 249         /* Convert (outertype)((innertype0)a+(innertype1)b)
 250            into ((newtype)a+(newtype)b) where newtype
 251            is the widest mode from all of these.  */
 252         case PLUS_EXPR:
 253         case MINUS_EXPR:
 254         case MULT_EXPR:
 255         case RDIV_EXPR:
 256            {
 257              tree arg0 = strip_float_extensions (TREE_OPERAND (expr, 0));
 258              tree arg1 = strip_float_extensions (TREE_OPERAND (expr, 1));
 259
 260              if (FLOAT_TYPE_P (TREE_TYPE (arg0))
 261                  && FLOAT_TYPE_P (TREE_TYPE (arg1)))
 262                {
 263                   tree newtype = type;
 264                   if (TYPE_PRECISION (TREE_TYPE (arg0)) > TYPE_PRECISION (newtype))
 265                     newtype = TREE_TYPE (arg0);
 266                   if (TYPE_PRECISION (TREE_TYPE (arg1)) > TYPE_PRECISION (newtype))
 267                     newtype = TREE_TYPE (arg1);
 268                   if (TYPE_PRECISION (newtype) < TYPE_PRECISION (itype))
 269                     {
 270                       expr = build2 (TREE_CODE (expr), newtype,
 271                                      fold (convert_to_real (newtype, arg0)),
 272                                      fold (convert_to_real (newtype, arg1)));
 273                       if (newtype == type)
 274                         return expr;
 275                     }
 276                }
 277            }
 278           break;
 279         default:
 280           break;
 281       }
 282
 283   switch (TREE_CODE (TREE_TYPE (expr)))
 284     {
 285     case REAL_TYPE:
 286       return build1 (flag_float_store ? CONVERT_EXPR : NOP_EXPR,
 287                      type, expr);
 288
 289     case INTEGER_TYPE:
 290     case ENUMERAL_TYPE:
 291     case BOOLEAN_TYPE:
 292     case CHAR_TYPE:
 293       return build1 (FLOAT_EXPR, type, expr);
 294
 295     case COMPLEX_TYPE:
 296       return convert (type,
 297                       fold (build1 (REALPART_EXPR,
 298                                     TREE_TYPE (TREE_TYPE (expr)), expr)));
 299
 300     case POINTER_TYPE:
 301     case REFERENCE_TYPE:
 302       error ("pointer value used where a floating point value was expected");
 303       return convert_to_real (type, integer_zero_node);
 304
 305     default:
 306       error ("aggregate value used where a float was expected");
 307       return convert_to_real (type, integer_zero_node);
 308     }
 309 }
 310
 311 /* Convert EXPR to some integer (or enum) type TYPE.
 312
 313    EXPR must be pointer, integer, discrete (enum, char, or bool), float, or
 314    vector; in other cases error is called.
 315
 316    The result of this is always supposed to be a newly created tree node
 317    not in use in any existing structure.  */
 318
 319 tree
 320 convert_to_integer (tree type, tree expr)
 321 {
 322   enum tree_code ex_form = TREE_CODE (expr);
 323   tree intype = TREE_TYPE (expr);
 324   unsigned int inprec = TYPE_PRECISION (intype);
 325   unsigned int outprec = TYPE_PRECISION (type);
 326
 327   /* An INTEGER_TYPE cannot be incomplete, but an ENUMERAL_TYPE can
 328      be.  Consider `enum E = { a, b = (enum E) 3 };'.  */
 329   if (!COMPLETE_TYPE_P (type))
 330     {
 331       error ("conversion to incomplete type");
 332       return error_mark_node;
 333     }
 334
 335   /* Convert e.g. (long)round(d) -> lround(d).  */
 336   /* If we're converting to char, we may encounter differing behavior
 337      between converting from double->char vs double->long->char.
 338      We're in "undefined" territory but we prefer to be conservative,
 339      so only proceed in "unsafe" math mode.  */
 340   if (optimize
 341       && (flag_unsafe_math_optimizations
 342           || (long_integer_type_node
 343               && outprec >= TYPE_PRECISION (long_integer_type_node))))
 344     {
 345       tree s_expr = strip_float_extensions (expr);
 346       tree s_intype = TREE_TYPE (s_expr);
 347       const enum built_in_function fcode = builtin_mathfn_code (s_expr);
 348       tree fn = 0;
 349
 350       switch (fcode)
 351         {
 352         case BUILT_IN_ROUND: case BUILT_IN_ROUNDF: case BUILT_IN_ROUNDL:
 353           if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (long_long_integer_type_node))
 354             fn = mathfn_built_in (s_intype, BUILT_IN_LLROUND);
 355           else
 356             fn = mathfn_built_in (s_intype, BUILT_IN_LROUND);
 357           break;
 358
 359         case BUILT_IN_RINT: case BUILT_IN_RINTF: case BUILT_IN_RINTL:
 360           /* Only convert rint* if we can ignore math exceptions.  */
 361           if (flag_trapping_math)
 362             break;
 363           /* ... Fall through ...  */
 364         case BUILT_IN_NEARBYINT: case BUILT_IN_NEARBYINTF: case BUILT_IN_NEARBYINTL:
 365           if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (long_long_integer_type_node))
 366             fn = mathfn_built_in (s_intype, BUILT_IN_LLRINT);
 367           else
 368             fn = mathfn_built_in (s_intype, BUILT_IN_LRINT);
 369           break;
 370         default:
 371           break;
 372         }
 373
 374       if (fn)
 375         {
 376           tree arglist = TREE_OPERAND (s_expr, 1);
 377           tree newexpr = build_function_call_expr (fn, arglist);
 378           return convert_to_integer (type, newexpr);
 379         }
 380     }
 381
 382   switch (TREE_CODE (intype))
 383     {
 384     case POINTER_TYPE:
 385     case REFERENCE_TYPE:
 386       if (integer_zerop (expr))
 387         expr = integer_zero_node;
 388       else
 389         expr = fold (build1 (CONVERT_EXPR,
 390                              lang_hooks.types.type_for_size
 391                                 (POINTER_SIZE, TYPE_UNSIGNED (type)),
 392                              expr));
 393
 394       return convert_to_integer (type, expr);
 395
 396     case INTEGER_TYPE:
 397     case ENUMERAL_TYPE:
 398     case BOOLEAN_TYPE:
 399     case CHAR_TYPE:
 400       /* If this is a logical operation, which just returns 0 or 1, we can
 401          change the type of the expression.  */
 402
 403       if (TREE_CODE_CLASS (ex_form) == tcc_comparison)
 404         {
 405           expr = copy_node (expr);
 406           TREE_TYPE (expr) = type;
 407           return expr;
 408         }
 409
 410       /* If we are widening the type, put in an explicit conversion.
 411          Similarly if we are not changing the width.  After this, we know
 412          we are truncating EXPR.  */
 413
 414       else if (outprec >= inprec)
 415         {
 416           enum tree_code code;
 417
 418           /* If the precision of the EXPR's type is K bits and the
 419              destination mode has more bits, and the sign is changing,
 420              it is not safe to use a NOP_EXPR.  For example, suppose
 421              that EXPR's type is a 3-bit unsigned integer type, the
 422              TYPE is a 3-bit signed integer type, and the machine mode
 423              for the types is 8-bit QImode.  In that case, the
 424              conversion necessitates an explicit sign-extension.  In
 425              the signed-to-unsigned case the high-order bits have to
 426              be cleared.  */
 427           if (TYPE_UNSIGNED (type) != TYPE_UNSIGNED (TREE_TYPE (expr))
 428               && (TYPE_PRECISION (TREE_TYPE (expr))
 429                   != GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (expr)))))
 430             code = CONVERT_EXPR;
 431           else
 432             code = NOP_EXPR;
 433
 434           return build1 (code, type, expr);
 435         }
 436
 437       /* If TYPE is an enumeral type or a type with a precision less
 438          than the number of bits in its mode, do the conversion to the
 439          type corresponding to its mode, then do a nop conversion
 440          to TYPE.  */
 441       else if (TREE_CODE (type) == ENUMERAL_TYPE
 442                || outprec != GET_MODE_BITSIZE (TYPE_MODE (type)))
 443         return build1 (NOP_EXPR, type,
 444                        convert (lang_hooks.types.type_for_mode
 445                                 (TYPE_MODE (type), TYPE_UNSIGNED (type)),
 446                                 expr));
 447
 448       /* Here detect when we can distribute the truncation down past some
 449          arithmetic.  For example, if adding two longs and converting to an
 450          int, we can equally well convert both to ints and then add.
 451          For the operations handled here, such truncation distribution
 452          is always safe.
 453          It is desirable in these cases:
 454          1) when truncating down to full-word from a larger size
 455          2) when truncating takes no work.
 456          3) when at least one operand of the arithmetic has been extended
 457          (as by C's default conversions).  In this case we need two conversions
 458          if we do the arithmetic as already requested, so we might as well
 459          truncate both and then combine.  Perhaps that way we need only one.
 460
 461          Note that in general we cannot do the arithmetic in a type
 462          shorter than the desired result of conversion, even if the operands
 463          are both extended from a shorter type, because they might overflow
 464          if combined in that type.  The exceptions to this--the times when
 465          two narrow values can be combined in their narrow type even to
 466          make a wider result--are handled by "shorten" in build_binary_op.  */
 467
 468       switch (ex_form)
 469         {
 470         case RSHIFT_EXPR:
 471           /* We can pass truncation down through right shifting
 472              when the shift count is a nonpositive constant.  */
 473           if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST
 474               && tree_int_cst_lt (TREE_OPERAND (expr, 1),
 475                                   convert (TREE_TYPE (TREE_OPERAND (expr, 1)),
 476                                            integer_one_node)))
 477             goto trunc1;
 478           break;
 479
 480         case LSHIFT_EXPR:
 481           /* We can pass truncation down through left shifting
 482              when the shift count is a nonnegative constant and
 483              the target type is unsigned.  */
 484           if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST
 485               && tree_int_cst_sgn (TREE_OPERAND (expr, 1)) >= 0
 486               && TYPE_UNSIGNED (type)
 487               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
 488             {
 489               /* If shift count is less than the width of the truncated type,
 490                  really shift.  */
 491               if (tree_int_cst_lt (TREE_OPERAND (expr, 1), TYPE_SIZE (type)))
 492                 /* In this case, shifting is like multiplication.  */
 493                 goto trunc1;
 494               else
 495                 {
 496                   /* If it is >= that width, result is zero.
 497                      Handling this with trunc1 would give the wrong result:
 498                      (int) ((long long) a << 32) is well defined (as 0)
 499                      but (int) a << 32 is undefined and would get a
 500                      warning.  */
 501
 502                   tree t = convert_to_integer (type, integer_zero_node);
 503
 504                   /* If the original expression had side-effects, we must
 505                      preserve it.  */
 506                   if (TREE_SIDE_EFFECTS (expr))
 507                     return build2 (COMPOUND_EXPR, type, expr, t);
 508                   else
 509                     return t;
 510                 }
 511             }
 512           break;
 513
 514         case MAX_EXPR:
 515         case MIN_EXPR:
 516         case MULT_EXPR:
 517           {
 518             tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
 519             tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
 520
 521             /* Don't distribute unless the output precision is at least as big
 522                as the actual inputs.  Otherwise, the comparison of the
 523                truncated values will be wrong.  */
 524             if (outprec >= TYPE_PRECISION (TREE_TYPE (arg0))
 525                 && outprec >= TYPE_PRECISION (TREE_TYPE (arg1))
 526                 /* If signedness of arg0 and arg1 don't match,
 527                    we can't necessarily find a type to compare them in.  */
 528                 && (TYPE_UNSIGNED (TREE_TYPE (arg0))
 529                     == TYPE_UNSIGNED (TREE_TYPE (arg1))))
 530               goto trunc1;
 531             break;
 532           }
 533
 534         case PLUS_EXPR:
 535         case MINUS_EXPR:
 536         case BIT_AND_EXPR:
 537         case BIT_IOR_EXPR:
 538         case BIT_XOR_EXPR:
 539         trunc1:
 540           {
 541             tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
 542             tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
 543
 544             if (outprec >= BITS_PER_WORD
 545                 || TRULY_NOOP_TRUNCATION (outprec, inprec)
 546                 || inprec > TYPE_PRECISION (TREE_TYPE (arg0))
 547                 || inprec > TYPE_PRECISION (TREE_TYPE (arg1)))
 548               {
 549                 /* Do the arithmetic in type TYPEX,
 550                    then convert result to TYPE.  */
 551                 tree typex = type;
 552
 553                 /* Can't do arithmetic in enumeral types
 554                    so use an integer type that will hold the values.  */
 555                 if (TREE_CODE (typex) == ENUMERAL_TYPE)
 556                   typex = lang_hooks.types.type_for_size
 557                     (TYPE_PRECISION (typex), TYPE_UNSIGNED (typex));
 558
 559                 /* But now perhaps TYPEX is as wide as INPREC.
 560                    In that case, do nothing special here.
 561                    (Otherwise would recurse infinitely in convert.  */
 562                 if (TYPE_PRECISION (typex) != inprec)
 563                   {
 564                     /* Don't do unsigned arithmetic where signed was wanted,
 565                        or vice versa.
 566                        Exception: if both of the original operands were
 567                        unsigned then we can safely do the work as unsigned.
 568                        Exception: shift operations take their type solely
 569                        from the first argument.
 570                        Exception: the LSHIFT_EXPR case above requires that
 571                        we perform this operation unsigned lest we produce
 572                        signed-overflow undefinedness.
 573                        And we may need to do it as unsigned
 574                        if we truncate to the original size.  */
 575                     if (TYPE_UNSIGNED (TREE_TYPE (expr))
 576                         || (TYPE_UNSIGNED (TREE_TYPE (arg0))
 577                             && (TYPE_UNSIGNED (TREE_TYPE (arg1))
 578                                 || ex_form == LSHIFT_EXPR
 579                                 || ex_form == RSHIFT_EXPR
 580                                 || ex_form == LROTATE_EXPR
 581                                 || ex_form == RROTATE_EXPR))
 582                         || ex_form == LSHIFT_EXPR)
 583                       typex = lang_hooks.types.unsigned_type (typex);
 584                     else
 585                       typex = lang_hooks.types.signed_type (typex);
 586                     return convert (type,
 587                                     fold (build2 (ex_form, typex,
 588                                                   convert (typex, arg0),
 589                                                   convert (typex, arg1))));
 590                   }
 591               }
 592           }
 593           break;
 594
 595         case NEGATE_EXPR:
 596         case BIT_NOT_EXPR:
 597           /* This is not correct for ABS_EXPR,
 598              since we must test the sign before truncation.  */
 599           {
 600             tree typex = type;
 601
 602             /* Can't do arithmetic in enumeral types
 603                so use an integer type that will hold the values.  */
 604             if (TREE_CODE (typex) == ENUMERAL_TYPE)
 605               typex = lang_hooks.types.type_for_size
 606                 (TYPE_PRECISION (typex), TYPE_UNSIGNED (typex));
 607
 608             /* But now perhaps TYPEX is as wide as INPREC.
 609                In that case, do nothing special here.
 610                (Otherwise would recurse infinitely in convert.  */
 611             if (TYPE_PRECISION (typex) != inprec)
 612               {
 613                 /* Don't do unsigned arithmetic where signed was wanted,
 614                    or vice versa.  */
 615                 if (TYPE_UNSIGNED (TREE_TYPE (expr)))
 616                   typex = lang_hooks.types.unsigned_type (typex);
 617                 else
 618                   typex = lang_hooks.types.signed_type (typex);
 619                 return convert (type,
 620                                 fold (build1 (ex_form, typex,
 621                                               convert (typex,
 622                                                        TREE_OPERAND (expr, 0)))));
 623               }
 624           }
 625
 626         case NOP_EXPR:
 627           /* Don't introduce a
 628              "can't convert between vector values of different size" error.  */
 629           if (TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == VECTOR_TYPE
 630               && (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_OPERAND (expr, 0))))
 631                   != GET_MODE_SIZE (TYPE_MODE (type))))
 632             break;
 633           /* If truncating after truncating, might as well do all at once.
 634              If truncating after extending, we may get rid of wasted work.  */
 635           return convert (type, get_unwidened (TREE_OPERAND (expr, 0), type));
 636
 637         case COND_EXPR:
 638           /* It is sometimes worthwhile to push the narrowing down through
 639              the conditional and never loses.  */
 640           return fold (build3 (COND_EXPR, type, TREE_OPERAND (expr, 0),
 641                                convert (type, TREE_OPERAND (expr, 1)),
 642                                convert (type, TREE_OPERAND (expr, 2))));
 643
 644         default:
 645           break;
 646         }
 647
 648       return build1 (CONVERT_EXPR, type, expr);
 649
 650     case REAL_TYPE:
 651       return build1 (FIX_TRUNC_EXPR, type, expr);
 652
 653     case COMPLEX_TYPE:
 654       return convert (type,
 655                       fold (build1 (REALPART_EXPR,
 656                                     TREE_TYPE (TREE_TYPE (expr)), expr)));
 657
 658     case VECTOR_TYPE:
 659       if (!tree_int_cst_equal (TYPE_SIZE (type), TYPE_SIZE (TREE_TYPE (expr))))
 660         {
 661           error ("can't convert between vector values of different size");
 662           return error_mark_node;
 663         }
 664       return build1 (NOP_EXPR, type, expr);
 665
 666     default:
 667       error ("aggregate value used where an integer was expected");
 668       return convert (type, integer_zero_node);
 669     }
 670 }
 671
 672 /* Convert EXPR to the complex type TYPE in the usual ways.  */
 673
 674 tree
 675 convert_to_complex (tree type, tree expr)
 676 {
 677   tree subtype = TREE_TYPE (type);
 678
 679   switch (TREE_CODE (TREE_TYPE (expr)))
 680     {
 681     case REAL_TYPE:
 682     case INTEGER_TYPE:
 683     case ENUMERAL_TYPE:
 684     case BOOLEAN_TYPE:
 685     case CHAR_TYPE:
 686       return build2 (COMPLEX_EXPR, type, convert (subtype, expr),
 687                      convert (subtype, integer_zero_node));
 688
 689     case COMPLEX_TYPE:
 690       {
 691         tree elt_type = TREE_TYPE (TREE_TYPE (expr));
 692
 693         if (TYPE_MAIN_VARIANT (elt_type) == TYPE_MAIN_VARIANT (subtype))
 694           return expr;
 695         else if (TREE_CODE (expr) == COMPLEX_EXPR)
 696           return fold (build2 (COMPLEX_EXPR, type,
 697                                convert (subtype, TREE_OPERAND (expr, 0)),
 698                                convert (subtype, TREE_OPERAND (expr, 1))));
 699         else
 700           {
 701             expr = save_expr (expr);
 702             return
 703               fold (build2 (COMPLEX_EXPR, type,
 704                             convert (subtype,
 705                                      fold (build1 (REALPART_EXPR,
 706                                                    TREE_TYPE (TREE_TYPE (expr)),
 707                                                    expr))),
 708                             convert (subtype,
 709                                      fold (build1 (IMAGPART_EXPR,
 710                                                    TREE_TYPE (TREE_TYPE (expr)),
 711                                                    expr)))));
 712           }
 713       }
 714
 715     case POINTER_TYPE:
 716     case REFERENCE_TYPE:
 717       error ("pointer value used where a complex was expected");
 718       return convert_to_complex (type, integer_zero_node);
 719
 720     default:
 721       error ("aggregate value used where a complex was expected");
 722       return convert_to_complex (type, integer_zero_node);
 723     }
 724 }
 725
 726 /* Convert EXPR to the vector type TYPE in the usual ways.  */
 727
 728 tree
 729 convert_to_vector (tree type, tree expr)
 730 {
 731   switch (TREE_CODE (TREE_TYPE (expr)))
 732     {
 733     case INTEGER_TYPE:
 734     case VECTOR_TYPE:
 735       if (!tree_int_cst_equal (TYPE_SIZE (type), TYPE_SIZE (TREE_TYPE (expr))))
 736         {
 737           error ("can't convert between vector values of different size");
 738           return error_mark_node;
 739         }
 740       return build1 (NOP_EXPR, type, expr);
 741
 742     default:
 743       error ("can't convert value to a vector");
 744       return error_mark_node;
 745     }
 746 }