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, 2005 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, 51 Franklin Street, Fifth Floor, Boston, MA
  20 02110-1301, 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     return build_int_cst (type, 0);
  46
  47   switch (TREE_CODE (TREE_TYPE (expr)))
  48     {
  49     case POINTER_TYPE:
  50     case REFERENCE_TYPE:
  51       return build1 (NOP_EXPR, type, expr);
  52
  53     case INTEGER_TYPE:
  54     case ENUMERAL_TYPE:
  55     case BOOLEAN_TYPE:
  56     case CHAR_TYPE:
  57       if (TYPE_PRECISION (TREE_TYPE (expr)) != POINTER_SIZE)
  58         expr = fold_build1 (NOP_EXPR,
  59                             lang_hooks.types.type_for_size (POINTER_SIZE, 0),
  60                             expr);
  61       return fold_build1 (CONVERT_EXPR, type, expr);
  62
  63
  64     default:
  65       error ("cannot convert to a pointer type");
  66       return convert_to_pointer (type, integer_zero_node);
  67     }
  68 }
  69
  70 /* Avoid any floating point extensions from EXP.  */
  71 tree
  72 strip_float_extensions (tree exp)
  73 {
  74   tree sub, expt, subt;
  75
  76   /*  For floating point constant look up the narrowest type that can hold
  77       it properly and handle it like (type)(narrowest_type)constant.
  78       This way we can optimize for instance a=a*2.0 where "a" is float
  79       but 2.0 is double constant.  */
  80   if (TREE_CODE (exp) == REAL_CST)
  81     {
  82       REAL_VALUE_TYPE orig;
  83       tree type = NULL;
  84
  85       orig = TREE_REAL_CST (exp);
  86       if (TYPE_PRECISION (TREE_TYPE (exp)) > TYPE_PRECISION (float_type_node)
  87           && exact_real_truncate (TYPE_MODE (float_type_node), &orig))
  88         type = float_type_node;
  89       else if (TYPE_PRECISION (TREE_TYPE (exp))
  90                > TYPE_PRECISION (double_type_node)
  91                && exact_real_truncate (TYPE_MODE (double_type_node), &orig))
  92         type = double_type_node;
  93       if (type)
  94         return build_real (type, real_value_truncate (TYPE_MODE (type), orig));
  95     }
  96
  97   if (TREE_CODE (exp) != NOP_EXPR
  98       && TREE_CODE (exp) != CONVERT_EXPR)
  99     return exp;
 100
 101   sub = TREE_OPERAND (exp, 0);
 102   subt = TREE_TYPE (sub);
 103   expt = TREE_TYPE (exp);
 104
 105   if (!FLOAT_TYPE_P (subt))
 106     return exp;
 107
 108   if (TYPE_PRECISION (subt) > TYPE_PRECISION (expt))
 109     return exp;
 110
 111   return strip_float_extensions (sub);
 112 }
 113
 114
 115 /* Convert EXPR to some floating-point type TYPE.
 116
 117    EXPR must be float, integer, or enumeral;
 118    in other cases error is called.  */
 119
 120 tree
 121 convert_to_real (tree type, tree expr)
 122 {
 123   enum built_in_function fcode = builtin_mathfn_code (expr);
 124   tree itype = TREE_TYPE (expr);
 125
 126   /* Disable until we figure out how to decide whether the functions are
 127      present in runtime.  */
 128   /* Convert (float)sqrt((double)x) where x is float into sqrtf(x) */
 129   if (optimize
 130       && (TYPE_MODE (type) == TYPE_MODE (double_type_node)
 131           || TYPE_MODE (type) == TYPE_MODE (float_type_node)))
 132     {
 133       switch (fcode)
 134         {
 135 #define CASE_MATHFN(FN) case BUILT_IN_##FN: case BUILT_IN_##FN##L:
 136           CASE_MATHFN (ACOS)
 137           CASE_MATHFN (ACOSH)
 138           CASE_MATHFN (ASIN)
 139           CASE_MATHFN (ASINH)
 140           CASE_MATHFN (ATAN)
 141           CASE_MATHFN (ATANH)
 142           CASE_MATHFN (CBRT)
 143           CASE_MATHFN (COS)
 144           CASE_MATHFN (COSH)
 145           CASE_MATHFN (ERF)
 146           CASE_MATHFN (ERFC)
 147           CASE_MATHFN (EXP)
 148           CASE_MATHFN (EXP10)
 149           CASE_MATHFN (EXP2)
 150           CASE_MATHFN (EXPM1)
 151           CASE_MATHFN (FABS)
 152           CASE_MATHFN (GAMMA)
 153           CASE_MATHFN (J0)
 154           CASE_MATHFN (J1)
 155           CASE_MATHFN (LGAMMA)
 156           CASE_MATHFN (LOG)
 157           CASE_MATHFN (LOG10)
 158           CASE_MATHFN (LOG1P)
 159           CASE_MATHFN (LOG2)
 160           CASE_MATHFN (LOGB)
 161           CASE_MATHFN (POW10)
 162           CASE_MATHFN (SIN)
 163           CASE_MATHFN (SINH)
 164           CASE_MATHFN (SQRT)
 165           CASE_MATHFN (TAN)
 166           CASE_MATHFN (TANH)
 167           CASE_MATHFN (TGAMMA)
 168           CASE_MATHFN (Y0)
 169           CASE_MATHFN (Y1)
 170 #undef CASE_MATHFN
 171             {
 172               tree arg0 = strip_float_extensions (TREE_VALUE (TREE_OPERAND (expr, 1)));
 173               tree newtype = type;
 174
 175               /* We have (outertype)sqrt((innertype)x).  Choose the wider mode from
 176                  the both as the safe type for operation.  */
 177               if (TYPE_PRECISION (TREE_TYPE (arg0)) > TYPE_PRECISION (type))
 178                 newtype = TREE_TYPE (arg0);
 179
 180               /* Be careful about integer to fp conversions.
 181                  These may overflow still.  */
 182               if (FLOAT_TYPE_P (TREE_TYPE (arg0))
 183                   && TYPE_PRECISION (newtype) < TYPE_PRECISION (itype)
 184                   && (TYPE_MODE (newtype) == TYPE_MODE (double_type_node)
 185                       || TYPE_MODE (newtype) == TYPE_MODE (float_type_node)))
 186                 {
 187                   tree arglist;
 188                   tree fn = mathfn_built_in (newtype, fcode);
 189
 190                   if (fn)
 191                   {
 192                     arglist = build_tree_list (NULL_TREE, fold (convert_to_real (newtype, arg0)));
 193                     expr = build_function_call_expr (fn, arglist);
 194                     if (newtype == type)
 195                       return expr;
 196                   }
 197                 }
 198             }
 199         default:
 200           break;
 201         }
 202     }
 203   if (optimize
 204       && (((fcode == BUILT_IN_FLOORL
 205            || fcode == BUILT_IN_CEILL
 206            || fcode == BUILT_IN_ROUNDL
 207            || fcode == BUILT_IN_RINTL
 208            || fcode == BUILT_IN_TRUNCL
 209            || fcode == BUILT_IN_NEARBYINTL)
 210           && (TYPE_MODE (type) == TYPE_MODE (double_type_node)
 211               || TYPE_MODE (type) == TYPE_MODE (float_type_node)))
 212           || ((fcode == BUILT_IN_FLOOR
 213                || fcode == BUILT_IN_CEIL
 214                || fcode == BUILT_IN_ROUND
 215                || fcode == BUILT_IN_RINT
 216                || fcode == BUILT_IN_TRUNC
 217                || fcode == BUILT_IN_NEARBYINT)
 218               && (TYPE_MODE (type) == TYPE_MODE (float_type_node)))))
 219     {
 220       tree fn = mathfn_built_in (type, fcode);
 221
 222       if (fn)
 223         {
 224           tree arg
 225             = strip_float_extensions (TREE_VALUE (TREE_OPERAND (expr, 1)));
 226
 227           /* Make sure (type)arg0 is an extension, otherwise we could end up
 228              changing (float)floor(double d) into floorf((float)d), which is
 229              incorrect because (float)d uses round-to-nearest and can round
 230              up to the next integer.  */
 231           if (TYPE_PRECISION (type) >= TYPE_PRECISION (TREE_TYPE (arg)))
 232             return
 233               build_function_call_expr (fn,
 234                                         build_tree_list (NULL_TREE,
 235                                           fold (convert_to_real (type, arg))));
 236         }
 237     }
 238
 239   /* Propagate the cast into the operation.  */
 240   if (itype != type && FLOAT_TYPE_P (type))
 241     switch (TREE_CODE (expr))
 242       {
 243         /* Convert (float)-x into -(float)x.  This is always safe.  */
 244         case ABS_EXPR:
 245         case NEGATE_EXPR:
 246           if (TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (expr)))
 247             return build1 (TREE_CODE (expr), type,
 248                            fold (convert_to_real (type,
 249                                                   TREE_OPERAND (expr, 0))));
 250           break;
 251         /* Convert (outertype)((innertype0)a+(innertype1)b)
 252            into ((newtype)a+(newtype)b) where newtype
 253            is the widest mode from all of these.  */
 254         case PLUS_EXPR:
 255         case MINUS_EXPR:
 256         case MULT_EXPR:
 257         case RDIV_EXPR:
 258            {
 259              tree arg0 = strip_float_extensions (TREE_OPERAND (expr, 0));
 260              tree arg1 = strip_float_extensions (TREE_OPERAND (expr, 1));
 261
 262              if (FLOAT_TYPE_P (TREE_TYPE (arg0))
 263                  && FLOAT_TYPE_P (TREE_TYPE (arg1)))
 264                {
 265                   tree newtype = type;
 266                   if (TYPE_PRECISION (TREE_TYPE (arg0)) > TYPE_PRECISION (newtype))
 267                     newtype = TREE_TYPE (arg0);
 268                   if (TYPE_PRECISION (TREE_TYPE (arg1)) > TYPE_PRECISION (newtype))
 269                     newtype = TREE_TYPE (arg1);
 270                   if (TYPE_PRECISION (newtype) < TYPE_PRECISION (itype))
 271                     {
 272                       expr = build2 (TREE_CODE (expr), newtype,
 273                                      fold (convert_to_real (newtype, arg0)),
 274                                      fold (convert_to_real (newtype, arg1)));
 275                       if (newtype == type)
 276                         return expr;
 277                     }
 278                }
 279            }
 280           break;
 281         default:
 282           break;
 283       }
 284
 285   switch (TREE_CODE (TREE_TYPE (expr)))
 286     {
 287     case REAL_TYPE:
 288       return build1 (flag_float_store ? CONVERT_EXPR : NOP_EXPR,
 289                      type, expr);
 290
 291     case INTEGER_TYPE:
 292     case ENUMERAL_TYPE:
 293     case BOOLEAN_TYPE:
 294     case CHAR_TYPE:
 295       return build1 (FLOAT_EXPR, type, expr);
 296
 297     case COMPLEX_TYPE:
 298       return convert (type,
 299                       fold_build1 (REALPART_EXPR,
 300                                    TREE_TYPE (TREE_TYPE (expr)), expr));
 301
 302     case POINTER_TYPE:
 303     case REFERENCE_TYPE:
 304       error ("pointer value used where a floating point value was expected");
 305       return convert_to_real (type, integer_zero_node);
 306
 307     default:
 308       error ("aggregate value used where a float was expected");
 309       return convert_to_real (type, integer_zero_node);
 310     }
 311 }
 312
 313 /* Convert EXPR to some integer (or enum) type TYPE.
 314
 315    EXPR must be pointer, integer, discrete (enum, char, or bool), float, or
 316    vector; in other cases error is called.
 317
 318    The result of this is always supposed to be a newly created tree node
 319    not in use in any existing structure.  */
 320
 321 tree
 322 convert_to_integer (tree type, tree expr)
 323 {
 324   enum tree_code ex_form = TREE_CODE (expr);
 325   tree intype = TREE_TYPE (expr);
 326   unsigned int inprec = TYPE_PRECISION (intype);
 327   unsigned int outprec = TYPE_PRECISION (type);
 328
 329   /* An INTEGER_TYPE cannot be incomplete, but an ENUMERAL_TYPE can
 330      be.  Consider `enum E = { a, b = (enum E) 3 };'.  */
 331   if (!COMPLETE_TYPE_P (type))
 332     {
 333       error ("conversion to incomplete type");
 334       return error_mark_node;
 335     }
 336
 337   /* Convert e.g. (long)round(d) -> lround(d).  */
 338   /* If we're converting to char, we may encounter differing behavior
 339      between converting from double->char vs double->long->char.
 340      We're in "undefined" territory but we prefer to be conservative,
 341      so only proceed in "unsafe" math mode.  */
 342   if (optimize
 343       && (flag_unsafe_math_optimizations
 344           || (long_integer_type_node
 345               && outprec >= TYPE_PRECISION (long_integer_type_node))))
 346     {
 347       tree s_expr = strip_float_extensions (expr);
 348       tree s_intype = TREE_TYPE (s_expr);
 349       const enum built_in_function fcode = builtin_mathfn_code (s_expr);
 350       tree fn = 0;
 351
 352       switch (fcode)
 353         {
 354         CASE_FLT_FN (BUILT_IN_CEIL):
 355           /* Only convert in ISO C99 mode.  */
 356           if (!TARGET_C99_FUNCTIONS)
 357             break;
 358           if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (long_long_integer_type_node))
 359             fn = mathfn_built_in (s_intype, BUILT_IN_LLCEIL);
 360           else
 361             fn = mathfn_built_in (s_intype, BUILT_IN_LCEIL);
 362           break;
 363
 364         CASE_FLT_FN (BUILT_IN_FLOOR):
 365           /* Only convert in ISO C99 mode.  */
 366           if (!TARGET_C99_FUNCTIONS)
 367             break;
 368           if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (long_long_integer_type_node))
 369             fn = mathfn_built_in (s_intype, BUILT_IN_LLFLOOR);
 370           else
 371             fn = mathfn_built_in (s_intype, BUILT_IN_LFLOOR);
 372           break;
 373
 374         CASE_FLT_FN (BUILT_IN_ROUND):
 375           if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (long_long_integer_type_node))
 376             fn = mathfn_built_in (s_intype, BUILT_IN_LLROUND);
 377           else
 378             fn = mathfn_built_in (s_intype, BUILT_IN_LROUND);
 379           break;
 380
 381         CASE_FLT_FN (BUILT_IN_RINT):
 382           /* Only convert rint* if we can ignore math exceptions.  */
 383           if (flag_trapping_math)
 384             break;
 385           /* ... Fall through ...  */
 386         CASE_FLT_FN (BUILT_IN_NEARBYINT):
 387           if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (long_long_integer_type_node))
 388             fn = mathfn_built_in (s_intype, BUILT_IN_LLRINT);
 389           else
 390             fn = mathfn_built_in (s_intype, BUILT_IN_LRINT);
 391           break;
 392
 393         CASE_FLT_FN (BUILT_IN_TRUNC):
 394           {
 395             tree arglist = TREE_OPERAND (s_expr, 1);
 396             return convert_to_integer (type, TREE_VALUE (arglist));
 397           }
 398
 399         default:
 400           break;
 401         }
 402
 403       if (fn)
 404         {
 405           tree arglist = TREE_OPERAND (s_expr, 1);
 406           tree newexpr = build_function_call_expr (fn, arglist);
 407           return convert_to_integer (type, newexpr);
 408         }
 409     }
 410
 411   switch (TREE_CODE (intype))
 412     {
 413     case POINTER_TYPE:
 414     case REFERENCE_TYPE:
 415       if (integer_zerop (expr))
 416         return build_int_cst (type, 0);
 417
 418       /* Convert to an unsigned integer of the correct width first,
 419          and from there widen/truncate to the required type.  */
 420       expr = fold_build1 (CONVERT_EXPR,
 421                           lang_hooks.types.type_for_size (POINTER_SIZE, 0),
 422                           expr);
 423       return fold_convert (type, expr);
 424
 425     case INTEGER_TYPE:
 426     case ENUMERAL_TYPE:
 427     case BOOLEAN_TYPE:
 428     case CHAR_TYPE:
 429       /* If this is a logical operation, which just returns 0 or 1, we can
 430          change the type of the expression.  */
 431
 432       if (TREE_CODE_CLASS (ex_form) == tcc_comparison)
 433         {
 434           expr = copy_node (expr);
 435           TREE_TYPE (expr) = type;
 436           return expr;
 437         }
 438
 439       /* If we are widening the type, put in an explicit conversion.
 440          Similarly if we are not changing the width.  After this, we know
 441          we are truncating EXPR.  */
 442
 443       else if (outprec >= inprec)
 444         {
 445           enum tree_code code;
 446
 447           /* If the precision of the EXPR's type is K bits and the
 448              destination mode has more bits, and the sign is changing,
 449              it is not safe to use a NOP_EXPR.  For example, suppose
 450              that EXPR's type is a 3-bit unsigned integer type, the
 451              TYPE is a 3-bit signed integer type, and the machine mode
 452              for the types is 8-bit QImode.  In that case, the
 453              conversion necessitates an explicit sign-extension.  In
 454              the signed-to-unsigned case the high-order bits have to
 455              be cleared.  */
 456           if (TYPE_UNSIGNED (type) != TYPE_UNSIGNED (TREE_TYPE (expr))
 457               && (TYPE_PRECISION (TREE_TYPE (expr))
 458                   != GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (expr)))))
 459             code = CONVERT_EXPR;
 460           else
 461             code = NOP_EXPR;
 462
 463           return fold_build1 (code, type, expr);
 464         }
 465
 466       /* If TYPE is an enumeral type or a type with a precision less
 467          than the number of bits in its mode, do the conversion to the
 468          type corresponding to its mode, then do a nop conversion
 469          to TYPE.  */
 470       else if (TREE_CODE (type) == ENUMERAL_TYPE
 471                || outprec != GET_MODE_BITSIZE (TYPE_MODE (type)))
 472         return build1 (NOP_EXPR, type,
 473                        convert (lang_hooks.types.type_for_mode
 474                                 (TYPE_MODE (type), TYPE_UNSIGNED (type)),
 475                                 expr));
 476
 477       /* Here detect when we can distribute the truncation down past some
 478          arithmetic.  For example, if adding two longs and converting to an
 479          int, we can equally well convert both to ints and then add.
 480          For the operations handled here, such truncation distribution
 481          is always safe.
 482          It is desirable in these cases:
 483          1) when truncating down to full-word from a larger size
 484          2) when truncating takes no work.
 485          3) when at least one operand of the arithmetic has been extended
 486          (as by C's default conversions).  In this case we need two conversions
 487          if we do the arithmetic as already requested, so we might as well
 488          truncate both and then combine.  Perhaps that way we need only one.
 489
 490          Note that in general we cannot do the arithmetic in a type
 491          shorter than the desired result of conversion, even if the operands
 492          are both extended from a shorter type, because they might overflow
 493          if combined in that type.  The exceptions to this--the times when
 494          two narrow values can be combined in their narrow type even to
 495          make a wider result--are handled by "shorten" in build_binary_op.  */
 496
 497       switch (ex_form)
 498         {
 499         case RSHIFT_EXPR:
 500           /* We can pass truncation down through right shifting
 501              when the shift count is a nonpositive constant.  */
 502           if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST
 503               && tree_int_cst_sgn (TREE_OPERAND (expr, 1)) <= 0)
 504             goto trunc1;
 505           break;
 506
 507         case LSHIFT_EXPR:
 508           /* We can pass truncation down through left shifting
 509              when the shift count is a nonnegative constant and
 510              the target type is unsigned.  */
 511           if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST
 512               && tree_int_cst_sgn (TREE_OPERAND (expr, 1)) >= 0
 513               && TYPE_UNSIGNED (type)
 514               && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
 515             {
 516               /* If shift count is less than the width of the truncated type,
 517                  really shift.  */
 518               if (tree_int_cst_lt (TREE_OPERAND (expr, 1), TYPE_SIZE (type)))
 519                 /* In this case, shifting is like multiplication.  */
 520                 goto trunc1;
 521               else
 522                 {
 523                   /* If it is >= that width, result is zero.
 524                      Handling this with trunc1 would give the wrong result:
 525                      (int) ((long long) a << 32) is well defined (as 0)
 526                      but (int) a << 32 is undefined and would get a
 527                      warning.  */
 528
 529                   tree t = build_int_cst (type, 0);
 530
 531                   /* If the original expression had side-effects, we must
 532                      preserve it.  */
 533                   if (TREE_SIDE_EFFECTS (expr))
 534                     return build2 (COMPOUND_EXPR, type, expr, t);
 535                   else
 536                     return t;
 537                 }
 538             }
 539           break;
 540
 541         case MAX_EXPR:
 542         case MIN_EXPR:
 543         case MULT_EXPR:
 544           {
 545             tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
 546             tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
 547
 548             /* Don't distribute unless the output precision is at least as big
 549                as the actual inputs.  Otherwise, the comparison of the
 550                truncated values will be wrong.  */
 551             if (outprec >= TYPE_PRECISION (TREE_TYPE (arg0))
 552                 && outprec >= TYPE_PRECISION (TREE_TYPE (arg1))
 553                 /* If signedness of arg0 and arg1 don't match,
 554                    we can't necessarily find a type to compare them in.  */
 555                 && (TYPE_UNSIGNED (TREE_TYPE (arg0))
 556                     == TYPE_UNSIGNED (TREE_TYPE (arg1))))
 557               goto trunc1;
 558             break;
 559           }
 560
 561         case PLUS_EXPR:
 562         case MINUS_EXPR:
 563         case BIT_AND_EXPR:
 564         case BIT_IOR_EXPR:
 565         case BIT_XOR_EXPR:
 566         trunc1:
 567           {
 568             tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
 569             tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
 570
 571             if (outprec >= BITS_PER_WORD
 572                 || TRULY_NOOP_TRUNCATION (outprec, inprec)
 573                 || inprec > TYPE_PRECISION (TREE_TYPE (arg0))
 574                 || inprec > TYPE_PRECISION (TREE_TYPE (arg1)))
 575               {
 576                 /* Do the arithmetic in type TYPEX,
 577                    then convert result to TYPE.  */
 578                 tree typex = type;
 579
 580                 /* Can't do arithmetic in enumeral types
 581                    so use an integer type that will hold the values.  */
 582                 if (TREE_CODE (typex) == ENUMERAL_TYPE)
 583                   typex = lang_hooks.types.type_for_size
 584                     (TYPE_PRECISION (typex), TYPE_UNSIGNED (typex));
 585
 586                 /* But now perhaps TYPEX is as wide as INPREC.
 587                    In that case, do nothing special here.
 588                    (Otherwise would recurse infinitely in convert.  */
 589                 if (TYPE_PRECISION (typex) != inprec)
 590                   {
 591                     /* Don't do unsigned arithmetic where signed was wanted,
 592                        or vice versa.
 593                        Exception: if both of the original operands were
 594                        unsigned then we can safely do the work as unsigned.
 595                        Exception: shift operations take their type solely
 596                        from the first argument.
 597                        Exception: the LSHIFT_EXPR case above requires that
 598                        we perform this operation unsigned lest we produce
 599                        signed-overflow undefinedness.
 600                        And we may need to do it as unsigned
 601                        if we truncate to the original size.  */
 602                     if (TYPE_UNSIGNED (TREE_TYPE (expr))
 603                         || (TYPE_UNSIGNED (TREE_TYPE (arg0))
 604                             && (TYPE_UNSIGNED (TREE_TYPE (arg1))
 605                                 || ex_form == LSHIFT_EXPR
 606                                 || ex_form == RSHIFT_EXPR
 607                                 || ex_form == LROTATE_EXPR
 608                                 || ex_form == RROTATE_EXPR))
 609                         || ex_form == LSHIFT_EXPR)
 610                       typex = lang_hooks.types.unsigned_type (typex);
 611                     else
 612                       typex = lang_hooks.types.signed_type (typex);
 613                     return convert (type,
 614                                     fold_build2 (ex_form, typex,
 615                                                  convert (typex, arg0),
 616                                                  convert (typex, arg1)));
 617                   }
 618               }
 619           }
 620           break;
 621
 622         case NEGATE_EXPR:
 623         case BIT_NOT_EXPR:
 624           /* This is not correct for ABS_EXPR,
 625              since we must test the sign before truncation.  */
 626           {
 627             tree typex;
 628
 629             /* Don't do unsigned arithmetic where signed was wanted,
 630                or vice versa.  */
 631             if (TYPE_UNSIGNED (TREE_TYPE (expr)))
 632               typex = lang_hooks.types.unsigned_type (type);
 633             else
 634               typex = lang_hooks.types.signed_type (type);
 635             return convert (type,
 636                             fold_build1 (ex_form, typex,
 637                                          convert (typex,
 638                                                   TREE_OPERAND (expr, 0))));
 639           }
 640
 641         case NOP_EXPR:
 642           /* Don't introduce a
 643              "can't convert between vector values of different size" error.  */
 644           if (TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == VECTOR_TYPE
 645               && (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_OPERAND (expr, 0))))
 646                   != GET_MODE_SIZE (TYPE_MODE (type))))
 647             break;
 648           /* If truncating after truncating, might as well do all at once.
 649              If truncating after extending, we may get rid of wasted work.  */
 650           return convert (type, get_unwidened (TREE_OPERAND (expr, 0), type));
 651
 652         case COND_EXPR:
 653           /* It is sometimes worthwhile to push the narrowing down through
 654              the conditional and never loses.  */
 655           return fold_build3 (COND_EXPR, type, TREE_OPERAND (expr, 0),
 656                               convert (type, TREE_OPERAND (expr, 1)),
 657                               convert (type, TREE_OPERAND (expr, 2)));
 658
 659         default:
 660           break;
 661         }
 662
 663       return build1 (CONVERT_EXPR, type, expr);
 664
 665     case REAL_TYPE:
 666       return build1 (FIX_TRUNC_EXPR, type, expr);
 667
 668     case COMPLEX_TYPE:
 669       return convert (type,
 670                       fold_build1 (REALPART_EXPR,
 671                                    TREE_TYPE (TREE_TYPE (expr)), expr));
 672
 673     case VECTOR_TYPE:
 674       if (!tree_int_cst_equal (TYPE_SIZE (type), TYPE_SIZE (TREE_TYPE (expr))))
 675         {
 676           error ("can't convert between vector values of different size");
 677           return error_mark_node;
 678         }
 679       return build1 (VIEW_CONVERT_EXPR, type, expr);
 680
 681     default:
 682       error ("aggregate value used where an integer was expected");
 683       return convert (type, integer_zero_node);
 684     }
 685 }
 686
 687 /* Convert EXPR to the complex type TYPE in the usual ways.  */
 688
 689 tree
 690 convert_to_complex (tree type, tree expr)
 691 {
 692   tree subtype = TREE_TYPE (type);
 693
 694   switch (TREE_CODE (TREE_TYPE (expr)))
 695     {
 696     case REAL_TYPE:
 697     case INTEGER_TYPE:
 698     case ENUMERAL_TYPE:
 699     case BOOLEAN_TYPE:
 700     case CHAR_TYPE:
 701       return build2 (COMPLEX_EXPR, type, convert (subtype, expr),
 702                      convert (subtype, integer_zero_node));
 703
 704     case COMPLEX_TYPE:
 705       {
 706         tree elt_type = TREE_TYPE (TREE_TYPE (expr));
 707
 708         if (TYPE_MAIN_VARIANT (elt_type) == TYPE_MAIN_VARIANT (subtype))
 709           return expr;
 710         else if (TREE_CODE (expr) == COMPLEX_EXPR)
 711           return fold_build2 (COMPLEX_EXPR, type,
 712                               convert (subtype, TREE_OPERAND (expr, 0)),
 713                               convert (subtype, TREE_OPERAND (expr, 1)));
 714         else
 715           {
 716             expr = save_expr (expr);
 717             return
 718               fold_build2 (COMPLEX_EXPR, type,
 719                            convert (subtype,
 720                                     fold_build1 (REALPART_EXPR,
 721                                                  TREE_TYPE (TREE_TYPE (expr)),
 722                                                  expr)),
 723                            convert (subtype,
 724                                     fold_build1 (IMAGPART_EXPR,
 725                                                  TREE_TYPE (TREE_TYPE (expr)),
 726                                                  expr)));
 727           }
 728       }
 729
 730     case POINTER_TYPE:
 731     case REFERENCE_TYPE:
 732       error ("pointer value used where a complex was expected");
 733       return convert_to_complex (type, integer_zero_node);
 734
 735     default:
 736       error ("aggregate value used where a complex was expected");
 737       return convert_to_complex (type, integer_zero_node);
 738     }
 739 }
 740
 741 /* Convert EXPR to the vector type TYPE in the usual ways.  */
 742
 743 tree
 744 convert_to_vector (tree type, tree expr)
 745 {
 746   switch (TREE_CODE (TREE_TYPE (expr)))
 747     {
 748     case INTEGER_TYPE:
 749     case VECTOR_TYPE:
 750       if (!tree_int_cst_equal (TYPE_SIZE (type), TYPE_SIZE (TREE_TYPE (expr))))
 751         {
 752           error ("can't convert between vector values of different size");
 753           return error_mark_node;
 754         }
 755       return build1 (VIEW_CONVERT_EXPR, type, expr);
 756
 757     default:
 758       error ("can't convert value to a vector");
 759       return error_mark_node;
 760     }
 761 }