gcc/convert.c

   1 /* Utility routines for data type conversion for GCC.
   2    Copyright (C) 1987-2016 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20
  21 /* These routines are somewhat language-independent utility function
  22    intended to be called by the language-specific convert () functions.  */
  23
  24 #include "config.h"
  25 #include "system.h"
  26 #include "coretypes.h"
  27 #include "target.h"
  28 #include "tree.h"
  29 #include "diagnostic-core.h"
  30 #include "fold-const.h"
  31 #include "stor-layout.h"
  32 #include "convert.h"
  33 #include "langhooks.h"
  34 #include "builtins.h"
  35 #include "ubsan.h"
  36
  37 #define maybe_fold_build1_loc(FOLD_P, LOC, CODE, TYPE, EXPR) \
  38   ((FOLD_P) ? fold_build1_loc (LOC, CODE, TYPE, EXPR)        \
  39    : build1_loc (LOC, CODE, TYPE, EXPR))
  40 #define maybe_fold_build2_loc(FOLD_P, LOC, CODE, TYPE, EXPR1, EXPR2) \
  41   ((FOLD_P) ? fold_build2_loc (LOC, CODE, TYPE, EXPR1, EXPR2)        \
  42    : build2_loc (LOC, CODE, TYPE, EXPR1, EXPR2))
  43
  44 /* Convert EXPR to some pointer or reference type TYPE.
  45    EXPR must be pointer, reference, integer, enumeral, or literal zero;
  46    in other cases error is called.  If FOLD_P is true, try to fold the
  47    expression.  */
  48
  49 static tree
  50 convert_to_pointer_1 (tree type, tree expr, bool fold_p)
  51 {
  52   location_t loc = EXPR_LOCATION (expr);
  53   if (TREE_TYPE (expr) == type)
  54     return expr;
  55
  56   switch (TREE_CODE (TREE_TYPE (expr)))
  57     {
  58     case POINTER_TYPE:
  59     case REFERENCE_TYPE:
  60       {
  61         /* If the pointers point to different address spaces, conversion needs
  62            to be done via a ADDR_SPACE_CONVERT_EXPR instead of a NOP_EXPR.  */
  63         addr_space_t to_as = TYPE_ADDR_SPACE (TREE_TYPE (type));
  64         addr_space_t from_as = TYPE_ADDR_SPACE (TREE_TYPE (TREE_TYPE (expr)));
  65
  66         if (to_as == from_as)
  67           return maybe_fold_build1_loc (fold_p, loc, NOP_EXPR, type, expr);
  68         else
  69           return maybe_fold_build1_loc (fold_p, loc, ADDR_SPACE_CONVERT_EXPR,
  70                                         type, expr);
  71       }
  72
  73     case INTEGER_TYPE:
  74     case ENUMERAL_TYPE:
  75     case BOOLEAN_TYPE:
  76       {
  77         /* If the input precision differs from the target pointer type
  78            precision, first convert the input expression to an integer type of
  79            the target precision.  Some targets, e.g. VMS, need several pointer
  80            sizes to coexist so the latter isn't necessarily POINTER_SIZE.  */
  81         unsigned int pprec = TYPE_PRECISION (type);
  82         unsigned int eprec = TYPE_PRECISION (TREE_TYPE (expr));
  83
  84         if (eprec != pprec)
  85           expr
  86             = maybe_fold_build1_loc (fold_p, loc, NOP_EXPR,
  87                                      lang_hooks.types.type_for_size (pprec, 0),
  88                                      expr);
  89       }
  90       return maybe_fold_build1_loc (fold_p, loc, CONVERT_EXPR, type, expr);
  91
  92     default:
  93       error ("cannot convert to a pointer type");
  94       return convert_to_pointer_1 (type, integer_zero_node, fold_p);
  95     }
  96 }
  97
  98 /* A wrapper around convert_to_pointer_1 that always folds the
  99    expression.  */
 100
 101 tree
 102 convert_to_pointer (tree type, tree expr)
 103 {
 104   return convert_to_pointer_1 (type, expr, true);
 105 }
 106
 107 /* A wrapper around convert_to_pointer_1 that only folds the
 108    expression if DOFOLD, or if it is CONSTANT_CLASS_P.  */
 109
 110 tree
 111 convert_to_pointer_maybe_fold (tree type, tree expr, bool dofold)
 112 {
 113   return convert_to_pointer_1 (type, expr, dofold || CONSTANT_CLASS_P (expr));
 114 }
 115
 116 /* Convert EXPR to some floating-point type TYPE.
 117
 118    EXPR must be float, fixed-point, integer, or enumeral;
 119    in other cases error is called.  If FOLD_P is true, try to fold
 120    the expression.  */
 121
 122 static tree
 123 convert_to_real_1 (tree type, tree expr, bool fold_p)
 124 {
 125   enum built_in_function fcode = builtin_mathfn_code (expr);
 126   tree itype = TREE_TYPE (expr);
 127   location_t loc = EXPR_LOCATION (expr);
 128
 129   if (TREE_CODE (expr) == COMPOUND_EXPR)
 130     {
 131       tree t = convert_to_real_1 (type, TREE_OPERAND (expr, 1), fold_p);
 132       if (t == TREE_OPERAND (expr, 1))
 133         return expr;
 134       return build2_loc (EXPR_LOCATION (expr), COMPOUND_EXPR, TREE_TYPE (t),
 135                          TREE_OPERAND (expr, 0), t);
 136     }
 137
 138   /* Disable until we figure out how to decide whether the functions are
 139      present in runtime.  */
 140   /* Convert (float)sqrt((double)x) where x is float into sqrtf(x) */
 141   if (optimize
 142       && (TYPE_MODE (type) == TYPE_MODE (double_type_node)
 143           || TYPE_MODE (type) == TYPE_MODE (float_type_node)))
 144     {
 145       switch (fcode)
 146         {
 147 #define CASE_MATHFN(FN) case BUILT_IN_##FN: case BUILT_IN_##FN##L:
 148           CASE_MATHFN (COSH)
 149           CASE_MATHFN (EXP)
 150           CASE_MATHFN (EXP10)
 151           CASE_MATHFN (EXP2)
 152           CASE_MATHFN (EXPM1)
 153           CASE_MATHFN (GAMMA)
 154           CASE_MATHFN (J0)
 155           CASE_MATHFN (J1)
 156           CASE_MATHFN (LGAMMA)
 157           CASE_MATHFN (POW10)
 158           CASE_MATHFN (SINH)
 159           CASE_MATHFN (TGAMMA)
 160           CASE_MATHFN (Y0)
 161           CASE_MATHFN (Y1)
 162             /* The above functions may set errno differently with float
 163                input or output so this transformation is not safe with
 164                -fmath-errno.  */
 165             if (flag_errno_math)
 166               break;
 167           CASE_MATHFN (ACOS)
 168           CASE_MATHFN (ACOSH)
 169           CASE_MATHFN (ASIN)
 170           CASE_MATHFN (ASINH)
 171           CASE_MATHFN (ATAN)
 172           CASE_MATHFN (ATANH)
 173           CASE_MATHFN (CBRT)
 174           CASE_MATHFN (COS)
 175           CASE_MATHFN (ERF)
 176           CASE_MATHFN (ERFC)
 177           CASE_MATHFN (LOG)
 178           CASE_MATHFN (LOG10)
 179           CASE_MATHFN (LOG2)
 180           CASE_MATHFN (LOG1P)
 181           CASE_MATHFN (SIN)
 182           CASE_MATHFN (TAN)
 183           CASE_MATHFN (TANH)
 184             /* The above functions are not safe to do this conversion.  */
 185             if (!flag_unsafe_math_optimizations)
 186               break;
 187           CASE_MATHFN (SQRT)
 188           CASE_MATHFN (FABS)
 189           CASE_MATHFN (LOGB)
 190 #undef CASE_MATHFN
 191             {
 192               tree arg0 = strip_float_extensions (CALL_EXPR_ARG (expr, 0));
 193               tree newtype = type;
 194
 195               /* We have (outertype)sqrt((innertype)x).  Choose the wider mode from
 196                  the both as the safe type for operation.  */
 197               if (TYPE_PRECISION (TREE_TYPE (arg0)) > TYPE_PRECISION (type))
 198                 newtype = TREE_TYPE (arg0);
 199
 200               /* We consider to convert
 201
 202                      (T1) sqrtT2 ((T2) exprT3)
 203                  to
 204                      (T1) sqrtT4 ((T4) exprT3)
 205
 206                   , where T1 is TYPE, T2 is ITYPE, T3 is TREE_TYPE (ARG0),
 207                  and T4 is NEWTYPE.  All those types are of floating point types.
 208                  T4 (NEWTYPE) should be narrower than T2 (ITYPE). This conversion
 209                  is safe only if P1 >= P2*2+2, where P1 and P2 are precisions of
 210                  T2 and T4.  See the following URL for a reference:
 211                  http://stackoverflow.com/questions/9235456/determining-
 212                  floating-point-square-root
 213                  */
 214               if ((fcode == BUILT_IN_SQRT || fcode == BUILT_IN_SQRTL)
 215                   && !flag_unsafe_math_optimizations)
 216                 {
 217                   /* The following conversion is unsafe even the precision condition
 218                      below is satisfied:
 219
 220                      (float) sqrtl ((long double) double_val) -> (float) sqrt (double_val)
 221                     */
 222                   if (TYPE_MODE (type) != TYPE_MODE (newtype))
 223                     break;
 224
 225                   int p1 = REAL_MODE_FORMAT (TYPE_MODE (itype))->p;
 226                   int p2 = REAL_MODE_FORMAT (TYPE_MODE (newtype))->p;
 227                   if (p1 < p2 * 2 + 2)
 228                     break;
 229                 }
 230
 231               /* Be careful about integer to fp conversions.
 232                  These may overflow still.  */
 233               if (FLOAT_TYPE_P (TREE_TYPE (arg0))
 234                   && TYPE_PRECISION (newtype) < TYPE_PRECISION (itype)
 235                   && (TYPE_MODE (newtype) == TYPE_MODE (double_type_node)
 236                       || TYPE_MODE (newtype) == TYPE_MODE (float_type_node)))
 237                 {
 238                   tree fn = mathfn_built_in (newtype, fcode);
 239                   if (fn)
 240                     {
 241                       tree arg = convert_to_real_1 (newtype, arg0, fold_p);
 242                       expr = build_call_expr (fn, 1, arg);
 243                       if (newtype == type)
 244                         return expr;
 245                     }
 246                 }
 247             }
 248         default:
 249           break;
 250         }
 251     }
 252
 253   /* Propagate the cast into the operation.  */
 254   if (itype != type && FLOAT_TYPE_P (type))
 255     switch (TREE_CODE (expr))
 256       {
 257         /* Convert (float)-x into -(float)x.  This is safe for
 258            round-to-nearest rounding mode when the inner type is float.  */
 259         case ABS_EXPR:
 260         case NEGATE_EXPR:
 261           if (!flag_rounding_math
 262               && FLOAT_TYPE_P (itype)
 263               && TYPE_PRECISION (type) < TYPE_PRECISION (itype))
 264             {
 265               tree arg = convert_to_real_1 (type, TREE_OPERAND (expr, 0),
 266                                             fold_p);
 267               return build1 (TREE_CODE (expr), type, arg);
 268             }
 269           break;
 270         /* Convert (outertype)((innertype0)a+(innertype1)b)
 271            into ((newtype)a+(newtype)b) where newtype
 272            is the widest mode from all of these.  */
 273         case PLUS_EXPR:
 274         case MINUS_EXPR:
 275         case MULT_EXPR:
 276         case RDIV_EXPR:
 277            {
 278              tree arg0 = strip_float_extensions (TREE_OPERAND (expr, 0));
 279              tree arg1 = strip_float_extensions (TREE_OPERAND (expr, 1));
 280
 281              if (FLOAT_TYPE_P (TREE_TYPE (arg0))
 282                  && FLOAT_TYPE_P (TREE_TYPE (arg1))
 283                  && DECIMAL_FLOAT_TYPE_P (itype) == DECIMAL_FLOAT_TYPE_P (type))
 284                {
 285                   tree newtype = type;
 286
 287                   if (TYPE_MODE (TREE_TYPE (arg0)) == SDmode
 288                       || TYPE_MODE (TREE_TYPE (arg1)) == SDmode
 289                       || TYPE_MODE (type) == SDmode)
 290                     newtype = dfloat32_type_node;
 291                   if (TYPE_MODE (TREE_TYPE (arg0)) == DDmode
 292                       || TYPE_MODE (TREE_TYPE (arg1)) == DDmode
 293                       || TYPE_MODE (type) == DDmode)
 294                     newtype = dfloat64_type_node;
 295                   if (TYPE_MODE (TREE_TYPE (arg0)) == TDmode
 296                       || TYPE_MODE (TREE_TYPE (arg1)) == TDmode
 297                       || TYPE_MODE (type) == TDmode)
 298                     newtype = dfloat128_type_node;
 299                   if (newtype == dfloat32_type_node
 300                       || newtype == dfloat64_type_node
 301                       || newtype == dfloat128_type_node)
 302                     {
 303                       expr = build2 (TREE_CODE (expr), newtype,
 304                                      convert_to_real_1 (newtype, arg0,
 305                                                         fold_p),
 306                                      convert_to_real_1 (newtype, arg1,
 307                                                         fold_p));
 308                       if (newtype == type)
 309                         return expr;
 310                       break;
 311                     }
 312
 313                   if (TYPE_PRECISION (TREE_TYPE (arg0)) > TYPE_PRECISION (newtype))
 314                     newtype = TREE_TYPE (arg0);
 315                   if (TYPE_PRECISION (TREE_TYPE (arg1)) > TYPE_PRECISION (newtype))
 316                     newtype = TREE_TYPE (arg1);
 317                   /* Sometimes this transformation is safe (cannot
 318                      change results through affecting double rounding
 319                      cases) and sometimes it is not.  If NEWTYPE is
 320                      wider than TYPE, e.g. (float)((long double)double
 321                      + (long double)double) converted to
 322                      (float)(double + double), the transformation is
 323                      unsafe regardless of the details of the types
 324                      involved; double rounding can arise if the result
 325                      of NEWTYPE arithmetic is a NEWTYPE value half way
 326                      between two representable TYPE values but the
 327                      exact value is sufficiently different (in the
 328                      right direction) for this difference to be
 329                      visible in ITYPE arithmetic.  If NEWTYPE is the
 330                      same as TYPE, however, the transformation may be
 331                      safe depending on the types involved: it is safe
 332                      if the ITYPE has strictly more than twice as many
 333                      mantissa bits as TYPE, can represent infinities
 334                      and NaNs if the TYPE can, and has sufficient
 335                      exponent range for the product or ratio of two
 336                      values representable in the TYPE to be within the
 337                      range of normal values of ITYPE.  */
 338                   if (TYPE_PRECISION (newtype) < TYPE_PRECISION (itype)
 339                       && (flag_unsafe_math_optimizations
 340                           || (TYPE_PRECISION (newtype) == TYPE_PRECISION (type)
 341                               && real_can_shorten_arithmetic (TYPE_MODE (itype),
 342                                                               TYPE_MODE (type))
 343                               && !excess_precision_type (newtype))))
 344                     {
 345                       expr = build2 (TREE_CODE (expr), newtype,
 346                                      convert_to_real_1 (newtype, arg0,
 347                                                         fold_p),
 348                                      convert_to_real_1 (newtype, arg1,
 349                                                         fold_p));
 350                       if (newtype == type)
 351                         return expr;
 352                     }
 353                }
 354            }
 355           break;
 356         default:
 357           break;
 358       }
 359
 360   switch (TREE_CODE (TREE_TYPE (expr)))
 361     {
 362     case REAL_TYPE:
 363       /* Ignore the conversion if we don't need to store intermediate
 364          results and neither type is a decimal float.  */
 365       return build1_loc (loc,
 366                          (flag_float_store
 367                           || DECIMAL_FLOAT_TYPE_P (type)
 368                           || DECIMAL_FLOAT_TYPE_P (itype))
 369                          ? CONVERT_EXPR : NOP_EXPR, type, expr);
 370
 371     case INTEGER_TYPE:
 372     case ENUMERAL_TYPE:
 373     case BOOLEAN_TYPE:
 374       return build1 (FLOAT_EXPR, type, expr);
 375
 376     case FIXED_POINT_TYPE:
 377       return build1 (FIXED_CONVERT_EXPR, type, expr);
 378
 379     case COMPLEX_TYPE:
 380       return convert (type,
 381                       maybe_fold_build1_loc (fold_p, loc, REALPART_EXPR,
 382                                              TREE_TYPE (TREE_TYPE (expr)),
 383                                              expr));
 384
 385     case POINTER_TYPE:
 386     case REFERENCE_TYPE:
 387       error ("pointer value used where a floating point value was expected");
 388       return convert_to_real_1 (type, integer_zero_node, fold_p);
 389
 390     default:
 391       error ("aggregate value used where a float was expected");
 392       return convert_to_real_1 (type, integer_zero_node, fold_p);
 393     }
 394 }
 395
 396 /* A wrapper around convert_to_real_1 that always folds the
 397    expression.  */
 398
 399 tree
 400 convert_to_real (tree type, tree expr)
 401 {
 402   return convert_to_real_1 (type, expr, true);
 403 }
 404
 405 /* A wrapper around convert_to_real_1 that only folds the
 406    expression if DOFOLD, or if it is CONSTANT_CLASS_P.  */
 407
 408 tree
 409 convert_to_real_maybe_fold (tree type, tree expr, bool dofold)
 410 {
 411   return convert_to_real_1 (type, expr, dofold || CONSTANT_CLASS_P (expr));
 412 }
 413
 414 /* Convert EXPR to some integer (or enum) type TYPE.
 415
 416    EXPR must be pointer, integer, discrete (enum, char, or bool), float,
 417    fixed-point or vector; in other cases error is called.
 418
 419    If DOFOLD is TRUE, we try to simplify newly-created patterns by folding.
 420
 421    The result of this is always supposed to be a newly created tree node
 422    not in use in any existing structure.  */
 423
 424 static tree
 425 convert_to_integer_1 (tree type, tree expr, bool dofold)
 426 {
 427   enum tree_code ex_form = TREE_CODE (expr);
 428   tree intype = TREE_TYPE (expr);
 429   unsigned int inprec = element_precision (intype);
 430   unsigned int outprec = element_precision (type);
 431   location_t loc = EXPR_LOCATION (expr);
 432
 433   /* An INTEGER_TYPE cannot be incomplete, but an ENUMERAL_TYPE can
 434      be.  Consider `enum E = { a, b = (enum E) 3 };'.  */
 435   if (!COMPLETE_TYPE_P (type))
 436     {
 437       error ("conversion to incomplete type");
 438       return error_mark_node;
 439     }
 440
 441   if (ex_form == COMPOUND_EXPR)
 442     {
 443       tree t = convert_to_integer_1 (type, TREE_OPERAND (expr, 1), dofold);
 444       if (t == TREE_OPERAND (expr, 1))
 445         return expr;
 446       return build2_loc (EXPR_LOCATION (expr), COMPOUND_EXPR, TREE_TYPE (t),
 447                          TREE_OPERAND (expr, 0), t);
 448     }
 449
 450   /* Convert e.g. (long)round(d) -> lround(d).  */
 451   /* If we're converting to char, we may encounter differing behavior
 452      between converting from double->char vs double->long->char.
 453      We're in "undefined" territory but we prefer to be conservative,
 454      so only proceed in "unsafe" math mode.  */
 455   if (optimize
 456       && (flag_unsafe_math_optimizations
 457           || (long_integer_type_node
 458               && outprec >= TYPE_PRECISION (long_integer_type_node))))
 459     {
 460       tree s_expr = strip_float_extensions (expr);
 461       tree s_intype = TREE_TYPE (s_expr);
 462       const enum built_in_function fcode = builtin_mathfn_code (s_expr);
 463       tree fn = 0;
 464
 465       switch (fcode)
 466         {
 467         CASE_FLT_FN (BUILT_IN_CEIL):
 468           /* Only convert in ISO C99 mode.  */
 469           if (!targetm.libc_has_function (function_c99_misc))
 470             break;
 471           if (outprec < TYPE_PRECISION (integer_type_node)
 472               || (outprec == TYPE_PRECISION (integer_type_node)
 473                   && !TYPE_UNSIGNED (type)))
 474             fn = mathfn_built_in (s_intype, BUILT_IN_ICEIL);
 475           else if (outprec == TYPE_PRECISION (long_integer_type_node)
 476                    && !TYPE_UNSIGNED (type))
 477             fn = mathfn_built_in (s_intype, BUILT_IN_LCEIL);
 478           else if (outprec == TYPE_PRECISION (long_long_integer_type_node)
 479                    && !TYPE_UNSIGNED (type))
 480             fn = mathfn_built_in (s_intype, BUILT_IN_LLCEIL);
 481           break;
 482
 483         CASE_FLT_FN (BUILT_IN_FLOOR):
 484           /* Only convert in ISO C99 mode.  */
 485           if (!targetm.libc_has_function (function_c99_misc))
 486             break;
 487           if (outprec < TYPE_PRECISION (integer_type_node)
 488               || (outprec == TYPE_PRECISION (integer_type_node)
 489                   && !TYPE_UNSIGNED (type)))
 490             fn = mathfn_built_in (s_intype, BUILT_IN_IFLOOR);
 491           else if (outprec == TYPE_PRECISION (long_integer_type_node)
 492                    && !TYPE_UNSIGNED (type))
 493             fn = mathfn_built_in (s_intype, BUILT_IN_LFLOOR);
 494           else if (outprec == TYPE_PRECISION (long_long_integer_type_node)
 495                    && !TYPE_UNSIGNED (type))
 496             fn = mathfn_built_in (s_intype, BUILT_IN_LLFLOOR);
 497           break;
 498
 499         CASE_FLT_FN (BUILT_IN_ROUND):
 500           /* Only convert in ISO C99 mode and with -fno-math-errno.  */
 501           if (!targetm.libc_has_function (function_c99_misc) || flag_errno_math)
 502             break;
 503           if (outprec < TYPE_PRECISION (integer_type_node)
 504               || (outprec == TYPE_PRECISION (integer_type_node)
 505                   && !TYPE_UNSIGNED (type)))
 506             fn = mathfn_built_in (s_intype, BUILT_IN_IROUND);
 507           else if (outprec == TYPE_PRECISION (long_integer_type_node)
 508                    && !TYPE_UNSIGNED (type))
 509             fn = mathfn_built_in (s_intype, BUILT_IN_LROUND);
 510           else if (outprec == TYPE_PRECISION (long_long_integer_type_node)
 511                    && !TYPE_UNSIGNED (type))
 512             fn = mathfn_built_in (s_intype, BUILT_IN_LLROUND);
 513           break;
 514
 515         CASE_FLT_FN (BUILT_IN_NEARBYINT):
 516           /* Only convert nearbyint* if we can ignore math exceptions.  */
 517           if (flag_trapping_math)
 518             break;
 519           /* ... Fall through ...  */
 520         CASE_FLT_FN (BUILT_IN_RINT):
 521           /* Only convert in ISO C99 mode and with -fno-math-errno.  */
 522           if (!targetm.libc_has_function (function_c99_misc) || flag_errno_math)
 523             break;
 524           if (outprec < TYPE_PRECISION (integer_type_node)
 525               || (outprec == TYPE_PRECISION (integer_type_node)
 526                   && !TYPE_UNSIGNED (type)))
 527             fn = mathfn_built_in (s_intype, BUILT_IN_IRINT);
 528           else if (outprec == TYPE_PRECISION (long_integer_type_node)
 529                    && !TYPE_UNSIGNED (type))
 530             fn = mathfn_built_in (s_intype, BUILT_IN_LRINT);
 531           else if (outprec == TYPE_PRECISION (long_long_integer_type_node)
 532                    && !TYPE_UNSIGNED (type))
 533             fn = mathfn_built_in (s_intype, BUILT_IN_LLRINT);
 534           break;
 535
 536         CASE_FLT_FN (BUILT_IN_TRUNC):
 537           return convert_to_integer_1 (type, CALL_EXPR_ARG (s_expr, 0), dofold);
 538
 539         default:
 540           break;
 541         }
 542
 543       if (fn)
 544         {
 545           tree newexpr = build_call_expr (fn, 1, CALL_EXPR_ARG (s_expr, 0));
 546           return convert_to_integer_1 (type, newexpr, dofold);
 547         }
 548     }
 549
 550   /* Convert (int)logb(d) -> ilogb(d).  */
 551   if (optimize
 552       && flag_unsafe_math_optimizations
 553       && !flag_trapping_math && !flag_errno_math && flag_finite_math_only
 554       && integer_type_node
 555       && (outprec > TYPE_PRECISION (integer_type_node)
 556           || (outprec == TYPE_PRECISION (integer_type_node)
 557               && !TYPE_UNSIGNED (type))))
 558     {
 559       tree s_expr = strip_float_extensions (expr);
 560       tree s_intype = TREE_TYPE (s_expr);
 561       const enum built_in_function fcode = builtin_mathfn_code (s_expr);
 562       tree fn = 0;
 563
 564       switch (fcode)
 565         {
 566         CASE_FLT_FN (BUILT_IN_LOGB):
 567           fn = mathfn_built_in (s_intype, BUILT_IN_ILOGB);
 568           break;
 569
 570         default:
 571           break;
 572         }
 573
 574       if (fn)
 575         {
 576           tree newexpr = build_call_expr (fn, 1, CALL_EXPR_ARG (s_expr, 0));
 577           return convert_to_integer_1 (type, newexpr, dofold);
 578         }
 579     }
 580
 581   switch (TREE_CODE (intype))
 582     {
 583     case POINTER_TYPE:
 584     case REFERENCE_TYPE:
 585       if (integer_zerop (expr))
 586         return build_int_cst (type, 0);
 587
 588       /* Convert to an unsigned integer of the correct width first, and from
 589          there widen/truncate to the required type.  Some targets support the
 590          coexistence of multiple valid pointer sizes, so fetch the one we need
 591          from the type.  */
 592       if (!dofold)
 593         return build1 (CONVERT_EXPR, type, expr);
 594       expr = fold_build1 (CONVERT_EXPR,
 595                           lang_hooks.types.type_for_size
 596                             (TYPE_PRECISION (intype), 0),
 597                           expr);
 598       return fold_convert (type, expr);
 599
 600     case INTEGER_TYPE:
 601     case ENUMERAL_TYPE:
 602     case BOOLEAN_TYPE:
 603     case OFFSET_TYPE:
 604       /* If this is a logical operation, which just returns 0 or 1, we can
 605          change the type of the expression.  */
 606
 607       if (TREE_CODE_CLASS (ex_form) == tcc_comparison)
 608         {
 609           expr = copy_node (expr);
 610           TREE_TYPE (expr) = type;
 611           return expr;
 612         }
 613
 614       /* If we are widening the type, put in an explicit conversion.
 615          Similarly if we are not changing the width.  After this, we know
 616          we are truncating EXPR.  */
 617
 618       else if (outprec >= inprec)
 619         {
 620           enum tree_code code;
 621
 622           /* If the precision of the EXPR's type is K bits and the
 623              destination mode has more bits, and the sign is changing,
 624              it is not safe to use a NOP_EXPR.  For example, suppose
 625              that EXPR's type is a 3-bit unsigned integer type, the
 626              TYPE is a 3-bit signed integer type, and the machine mode
 627              for the types is 8-bit QImode.  In that case, the
 628              conversion necessitates an explicit sign-extension.  In
 629              the signed-to-unsigned case the high-order bits have to
 630              be cleared.  */
 631           if (TYPE_UNSIGNED (type) != TYPE_UNSIGNED (TREE_TYPE (expr))
 632               && (TYPE_PRECISION (TREE_TYPE (expr))
 633                   != GET_MODE_PRECISION (TYPE_MODE (TREE_TYPE (expr)))))
 634             code = CONVERT_EXPR;
 635           else
 636             code = NOP_EXPR;
 637
 638           return maybe_fold_build1_loc (dofold, loc, code, type, expr);
 639         }
 640
 641       /* If TYPE is an enumeral type or a type with a precision less
 642          than the number of bits in its mode, do the conversion to the
 643          type corresponding to its mode, then do a nop conversion
 644          to TYPE.  */
 645       else if (TREE_CODE (type) == ENUMERAL_TYPE
 646                || outprec != GET_MODE_PRECISION (TYPE_MODE (type)))
 647         return build1 (NOP_EXPR, type,
 648                        convert (lang_hooks.types.type_for_mode
 649                                 (TYPE_MODE (type), TYPE_UNSIGNED (type)),
 650                                 expr));
 651
 652       /* Here detect when we can distribute the truncation down past some
 653          arithmetic.  For example, if adding two longs and converting to an
 654          int, we can equally well convert both to ints and then add.
 655          For the operations handled here, such truncation distribution
 656          is always safe.
 657          It is desirable in these cases:
 658          1) when truncating down to full-word from a larger size
 659          2) when truncating takes no work.
 660          3) when at least one operand of the arithmetic has been extended
 661          (as by C's default conversions).  In this case we need two conversions
 662          if we do the arithmetic as already requested, so we might as well
 663          truncate both and then combine.  Perhaps that way we need only one.
 664
 665          Note that in general we cannot do the arithmetic in a type
 666          shorter than the desired result of conversion, even if the operands
 667          are both extended from a shorter type, because they might overflow
 668          if combined in that type.  The exceptions to this--the times when
 669          two narrow values can be combined in their narrow type even to
 670          make a wider result--are handled by "shorten" in build_binary_op.  */
 671
 672       if (dofold)
 673         switch (ex_form)
 674           {
 675           case RSHIFT_EXPR:
 676             /* We can pass truncation down through right shifting
 677                when the shift count is a nonpositive constant.  */
 678             if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST
 679                 && tree_int_cst_sgn (TREE_OPERAND (expr, 1)) <= 0)
 680               goto trunc1;
 681             break;
 682
 683           case LSHIFT_EXPR:
 684             /* We can pass truncation down through left shifting
 685                when the shift count is a nonnegative constant and
 686                the target type is unsigned.  */
 687             if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST
 688                 && tree_int_cst_sgn (TREE_OPERAND (expr, 1)) >= 0
 689                 && TYPE_UNSIGNED (type)
 690                 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
 691               {
 692                 /* If shift count is less than the width of the truncated type,
 693                    really shift.  */
 694                 if (tree_int_cst_lt (TREE_OPERAND (expr, 1), TYPE_SIZE (type)))
 695                   /* In this case, shifting is like multiplication.  */
 696                   goto trunc1;
 697                 else
 698                   {
 699                     /* If it is >= that width, result is zero.
 700                        Handling this with trunc1 would give the wrong result:
 701                        (int) ((long long) a << 32) is well defined (as 0)
 702                        but (int) a << 32 is undefined and would get a
 703                        warning.  */
 704
 705                     tree t = build_int_cst (type, 0);
 706
 707                     /* If the original expression had side-effects, we must
 708                        preserve it.  */
 709                     if (TREE_SIDE_EFFECTS (expr))
 710                       return build2 (COMPOUND_EXPR, type, expr, t);
 711                     else
 712                       return t;
 713                   }
 714               }
 715             break;
 716
 717           case TRUNC_DIV_EXPR:
 718             {
 719               tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
 720               tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
 721
 722               /* Don't distribute unless the output precision is at least as
 723                  big as the actual inputs and it has the same signedness.  */
 724               if (outprec >= TYPE_PRECISION (TREE_TYPE (arg0))
 725                   && outprec >= TYPE_PRECISION (TREE_TYPE (arg1))
 726                   /* If signedness of arg0 and arg1 don't match,
 727                      we can't necessarily find a type to compare them in.  */
 728                   && (TYPE_UNSIGNED (TREE_TYPE (arg0))
 729                       == TYPE_UNSIGNED (TREE_TYPE (arg1)))
 730                   /* Do not change the sign of the division.  */
 731                   && (TYPE_UNSIGNED (TREE_TYPE (expr))
 732                       == TYPE_UNSIGNED (TREE_TYPE (arg0)))
 733                   /* Either require unsigned division or a division by
 734                      a constant that is not -1.  */
 735                   && (TYPE_UNSIGNED (TREE_TYPE (arg0))
 736                       || (TREE_CODE (arg1) == INTEGER_CST
 737                           && !integer_all_onesp (arg1))))
 738                 goto trunc1;
 739               break;
 740             }
 741
 742           case MAX_EXPR:
 743           case MIN_EXPR:
 744           case MULT_EXPR:
 745             {
 746               tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
 747               tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
 748
 749               /* Don't distribute unless the output precision is at least as
 750                  big as the actual inputs.  Otherwise, the comparison of the
 751                  truncated values will be wrong.  */
 752               if (outprec >= TYPE_PRECISION (TREE_TYPE (arg0))
 753                   && outprec >= TYPE_PRECISION (TREE_TYPE (arg1))
 754                   /* If signedness of arg0 and arg1 don't match,
 755                      we can't necessarily find a type to compare them in.  */
 756                   && (TYPE_UNSIGNED (TREE_TYPE (arg0))
 757                       == TYPE_UNSIGNED (TREE_TYPE (arg1))))
 758                 goto trunc1;
 759               break;
 760             }
 761
 762           case PLUS_EXPR:
 763           case MINUS_EXPR:
 764           case BIT_AND_EXPR:
 765           case BIT_IOR_EXPR:
 766           case BIT_XOR_EXPR:
 767           trunc1:
 768             {
 769               tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
 770               tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
 771
 772               /* Do not try to narrow operands of pointer subtraction;
 773                  that will interfere with other folding.  */
 774               if (ex_form == MINUS_EXPR
 775                   && CONVERT_EXPR_P (arg0)
 776                   && CONVERT_EXPR_P (arg1)
 777                   && POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 0)))
 778                   && POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (arg1, 0))))
 779                 break;
 780
 781               if (outprec >= BITS_PER_WORD
 782                   || TRULY_NOOP_TRUNCATION (outprec, inprec)
 783                   || inprec > TYPE_PRECISION (TREE_TYPE (arg0))
 784                   || inprec > TYPE_PRECISION (TREE_TYPE (arg1)))
 785                 {
 786                   /* Do the arithmetic in type TYPEX,
 787                      then convert result to TYPE.  */
 788                   tree typex = type;
 789
 790                   /* Can't do arithmetic in enumeral types
 791                      so use an integer type that will hold the values.  */
 792                   if (TREE_CODE (typex) == ENUMERAL_TYPE)
 793                     typex
 794                       = lang_hooks.types.type_for_size (TYPE_PRECISION (typex),
 795                                                         TYPE_UNSIGNED (typex));
 796
 797                   /* But now perhaps TYPEX is as wide as INPREC.
 798                      In that case, do nothing special here.
 799                      (Otherwise would recurse infinitely in convert.  */
 800                   if (TYPE_PRECISION (typex) != inprec)
 801                     {
 802                       /* Don't do unsigned arithmetic where signed was wanted,
 803                          or vice versa.
 804                          Exception: if both of the original operands were
 805                          unsigned then we can safely do the work as unsigned.
 806                          Exception: shift operations take their type solely
 807                          from the first argument.
 808                          Exception: the LSHIFT_EXPR case above requires that
 809                          we perform this operation unsigned lest we produce
 810                          signed-overflow undefinedness.
 811                          And we may need to do it as unsigned
 812                          if we truncate to the original size.  */
 813                       if (TYPE_UNSIGNED (TREE_TYPE (expr))
 814                           || (TYPE_UNSIGNED (TREE_TYPE (arg0))
 815                               && (TYPE_UNSIGNED (TREE_TYPE (arg1))
 816                                   || ex_form == LSHIFT_EXPR
 817                                   || ex_form == RSHIFT_EXPR
 818                                   || ex_form == LROTATE_EXPR
 819                                   || ex_form == RROTATE_EXPR))
 820                           || ex_form == LSHIFT_EXPR
 821                           /* If we have !flag_wrapv, and either ARG0 or
 822                              ARG1 is of a signed type, we have to do
 823                              PLUS_EXPR, MINUS_EXPR or MULT_EXPR in an unsigned
 824                              type in case the operation in outprec precision
 825                              could overflow.  Otherwise, we would introduce
 826                              signed-overflow undefinedness.  */
 827                           || ((!TYPE_OVERFLOW_WRAPS (TREE_TYPE (arg0))
 828                                || !TYPE_OVERFLOW_WRAPS (TREE_TYPE (arg1)))
 829                               && ((TYPE_PRECISION (TREE_TYPE (arg0)) * 2u
 830                                    > outprec)
 831                                   || (TYPE_PRECISION (TREE_TYPE (arg1)) * 2u
 832                                       > outprec))
 833                               && (ex_form == PLUS_EXPR
 834                                   || ex_form == MINUS_EXPR
 835                                   || ex_form == MULT_EXPR)))
 836                         {
 837                           if (!TYPE_UNSIGNED (typex))
 838                             typex = unsigned_type_for (typex);
 839                         }
 840                       else
 841                         {
 842                           if (TYPE_UNSIGNED (typex))
 843                             typex = signed_type_for (typex);
 844                         }
 845                       /* We should do away with all this once we have a proper
 846                          type promotion/demotion pass, see PR45397.  */
 847                       expr = maybe_fold_build2_loc (dofold, loc, ex_form, typex,
 848                                                     convert (typex, arg0),
 849                                                     convert (typex, arg1));
 850                       return convert (type, expr);
 851                     }
 852                 }
 853             }
 854             break;
 855
 856           case NEGATE_EXPR:
 857           case BIT_NOT_EXPR:
 858             /* This is not correct for ABS_EXPR,
 859                since we must test the sign before truncation.  */
 860             {
 861               /* Do the arithmetic in type TYPEX,
 862                  then convert result to TYPE.  */
 863               tree typex = type;
 864
 865               /* Can't do arithmetic in enumeral types
 866                  so use an integer type that will hold the values.  */
 867               if (TREE_CODE (typex) == ENUMERAL_TYPE)
 868                 typex
 869                   = lang_hooks.types.type_for_size (TYPE_PRECISION (typex),
 870                                                     TYPE_UNSIGNED (typex));
 871
 872               if (!TYPE_UNSIGNED (typex))
 873                 typex = unsigned_type_for (typex);
 874               return convert (type,
 875                               fold_build1 (ex_form, typex,
 876                                            convert (typex,
 877                                                     TREE_OPERAND (expr, 0))));
 878             }
 879
 880           CASE_CONVERT:
 881             /* Don't introduce a "can't convert between vector values of
 882                different size" error.  */
 883             if (TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == VECTOR_TYPE
 884                 && (GET_MODE_SIZE (TYPE_MODE
 885                                    (TREE_TYPE (TREE_OPERAND (expr, 0))))
 886                     != GET_MODE_SIZE (TYPE_MODE (type))))
 887               break;
 888             /* If truncating after truncating, might as well do all at once.
 889                If truncating after extending, we may get rid of wasted work.  */
 890             return convert (type, get_unwidened (TREE_OPERAND (expr, 0), type));
 891
 892           case COND_EXPR:
 893             /* It is sometimes worthwhile to push the narrowing down through
 894                the conditional and never loses.  A COND_EXPR may have a throw
 895                as one operand, which then has void type.  Just leave void
 896                operands as they are.  */
 897             return
 898               fold_build3 (COND_EXPR, type, TREE_OPERAND (expr, 0),
 899                            VOID_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 1)))
 900                            ? TREE_OPERAND (expr, 1)
 901                            : convert (type, TREE_OPERAND (expr, 1)),
 902                            VOID_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 2)))
 903                            ? TREE_OPERAND (expr, 2)
 904                            : convert (type, TREE_OPERAND (expr, 2)));
 905
 906           default:
 907             break;
 908           }
 909
 910       /* When parsing long initializers, we might end up with a lot of casts.
 911          Shortcut this.  */
 912       if (TREE_CODE (expr) == INTEGER_CST)
 913         return fold_convert (type, expr);
 914       return build1 (CONVERT_EXPR, type, expr);
 915
 916     case REAL_TYPE:
 917       if (flag_sanitize & SANITIZE_FLOAT_CAST
 918           && do_ubsan_in_current_function ())
 919         {
 920           expr = save_expr (expr);
 921           tree check = ubsan_instrument_float_cast (loc, type, expr);
 922           expr = build1 (FIX_TRUNC_EXPR, type, expr);
 923           if (check == NULL_TREE)
 924             return expr;
 925           return maybe_fold_build2_loc (dofold, loc, COMPOUND_EXPR,
 926                                         TREE_TYPE (expr), check, expr);
 927         }
 928       else
 929         return build1 (FIX_TRUNC_EXPR, type, expr);
 930
 931     case FIXED_POINT_TYPE:
 932       return build1 (FIXED_CONVERT_EXPR, type, expr);
 933
 934     case COMPLEX_TYPE:
 935       expr = maybe_fold_build1_loc (dofold, loc, REALPART_EXPR,
 936                                     TREE_TYPE (TREE_TYPE (expr)), expr);
 937       return convert (type, expr);
 938
 939     case VECTOR_TYPE:
 940       if (!tree_int_cst_equal (TYPE_SIZE (type), TYPE_SIZE (TREE_TYPE (expr))))
 941         {
 942           error ("can%'t convert a vector of type %qT"
 943                  " to type %qT which has different size",
 944                  TREE_TYPE (expr), type);
 945           return error_mark_node;
 946         }
 947       return build1 (VIEW_CONVERT_EXPR, type, expr);
 948
 949     default:
 950       error ("aggregate value used where an integer was expected");
 951       return convert (type, integer_zero_node);
 952     }
 953 }
 954
 955 /* Convert EXPR to some integer (or enum) type TYPE.
 956
 957    EXPR must be pointer, integer, discrete (enum, char, or bool), float,
 958    fixed-point or vector; in other cases error is called.
 959
 960    The result of this is always supposed to be a newly created tree node
 961    not in use in any existing structure.  */
 962
 963 tree
 964 convert_to_integer (tree type, tree expr)
 965 {
 966   return convert_to_integer_1 (type, expr, true);
 967 }
 968
 969 /* A wrapper around convert_to_complex_1 that only folds the
 970    expression if DOFOLD, or if it is CONSTANT_CLASS_P.  */
 971
 972 tree
 973 convert_to_integer_maybe_fold (tree type, tree expr, bool dofold)
 974 {
 975   return convert_to_integer_1 (type, expr, dofold || CONSTANT_CLASS_P (expr));
 976 }
 977
 978 /* Convert EXPR to the complex type TYPE in the usual ways.  If FOLD_P is
 979    true, try to fold the expression.  */
 980
 981 static tree
 982 convert_to_complex_1 (tree type, tree expr, bool fold_p)
 983 {
 984   location_t loc = EXPR_LOCATION (expr);
 985   tree subtype = TREE_TYPE (type);
 986
 987   switch (TREE_CODE (TREE_TYPE (expr)))
 988     {
 989     case REAL_TYPE:
 990     case FIXED_POINT_TYPE:
 991     case INTEGER_TYPE:
 992     case ENUMERAL_TYPE:
 993     case BOOLEAN_TYPE:
 994       return build2 (COMPLEX_EXPR, type, convert (subtype, expr),
 995                      convert (subtype, integer_zero_node));
 996
 997     case COMPLEX_TYPE:
 998       {
 999         tree elt_type = TREE_TYPE (TREE_TYPE (expr));
1000
1001         if (TYPE_MAIN_VARIANT (elt_type) == TYPE_MAIN_VARIANT (subtype))
1002           return expr;
1003         else if (TREE_CODE (expr) == COMPOUND_EXPR)
1004           {
1005             tree t = convert_to_complex_1 (type, TREE_OPERAND (expr, 1),
1006                                            fold_p);
1007             if (t == TREE_OPERAND (expr, 1))
1008               return expr;
1009             return build2_loc (EXPR_LOCATION (expr), COMPOUND_EXPR,
1010                                TREE_TYPE (t), TREE_OPERAND (expr, 0), t);
1011           }
1012         else if (TREE_CODE (expr) == COMPLEX_EXPR)
1013           return maybe_fold_build2_loc (fold_p, loc, COMPLEX_EXPR, type,
1014                                         convert (subtype,
1015                                                  TREE_OPERAND (expr, 0)),
1016                                         convert (subtype,
1017                                                  TREE_OPERAND (expr, 1)));
1018         else
1019           {
1020             expr = save_expr (expr);
1021             tree realp = maybe_fold_build1_loc (fold_p, loc, REALPART_EXPR,
1022                                                 TREE_TYPE (TREE_TYPE (expr)),
1023                                                 expr);
1024             tree imagp = maybe_fold_build1_loc (fold_p, loc, IMAGPART_EXPR,
1025                                                 TREE_TYPE (TREE_TYPE (expr)),
1026                                                 expr);
1027             return maybe_fold_build2_loc (fold_p, loc, COMPLEX_EXPR, type,
1028                                           convert (subtype, realp),
1029                                           convert (subtype, imagp));
1030           }
1031       }
1032
1033     case POINTER_TYPE:
1034     case REFERENCE_TYPE:
1035       error ("pointer value used where a complex was expected");
1036       return convert_to_complex_1 (type, integer_zero_node, fold_p);
1037
1038     default:
1039       error ("aggregate value used where a complex was expected");
1040       return convert_to_complex_1 (type, integer_zero_node, fold_p);
1041     }
1042 }
1043
1044 /* A wrapper around convert_to_complex_1 that always folds the
1045    expression.  */
1046
1047 tree
1048 convert_to_complex (tree type, tree expr)
1049 {
1050   return convert_to_complex_1 (type, expr, true);
1051 }
1052
1053 /* A wrapper around convert_to_complex_1 that only folds the
1054    expression if DOFOLD, or if it is CONSTANT_CLASS_P.  */
1055
1056 tree
1057 convert_to_complex_maybe_fold (tree type, tree expr, bool dofold)
1058 {
1059   return convert_to_complex_1 (type, expr, dofold || CONSTANT_CLASS_P (expr));
1060 }
1061
1062 /* Convert EXPR to the vector type TYPE in the usual ways.  */
1063
1064 tree
1065 convert_to_vector (tree type, tree expr)
1066 {
1067   switch (TREE_CODE (TREE_TYPE (expr)))
1068     {
1069     case INTEGER_TYPE:
1070     case VECTOR_TYPE:
1071       if (!tree_int_cst_equal (TYPE_SIZE (type), TYPE_SIZE (TREE_TYPE (expr))))
1072         {
1073           error ("can%'t convert a value of type %qT"
1074                  " to vector type %qT which has different size",
1075                  TREE_TYPE (expr), type);
1076           return error_mark_node;
1077         }
1078       return build1 (VIEW_CONVERT_EXPR, type, expr);
1079
1080     default:
1081       error ("can%'t convert value to a vector");
1082       return error_mark_node;
1083     }
1084 }
1085
1086 /* Convert EXPR to some fixed-point type TYPE.
1087
1088    EXPR must be fixed-point, float, integer, or enumeral;
1089    in other cases error is called.  */
1090
1091 tree
1092 convert_to_fixed (tree type, tree expr)
1093 {
1094   if (integer_zerop (expr))
1095     {
1096       tree fixed_zero_node = build_fixed (type, FCONST0 (TYPE_MODE (type)));
1097       return fixed_zero_node;
1098     }
1099   else if (integer_onep (expr) && ALL_SCALAR_ACCUM_MODE_P (TYPE_MODE (type)))
1100     {
1101       tree fixed_one_node = build_fixed (type, FCONST1 (TYPE_MODE (type)));
1102       return fixed_one_node;
1103     }
1104
1105   switch (TREE_CODE (TREE_TYPE (expr)))
1106     {
1107     case FIXED_POINT_TYPE:
1108     case INTEGER_TYPE:
1109     case ENUMERAL_TYPE:
1110     case BOOLEAN_TYPE:
1111     case REAL_TYPE:
1112       return build1 (FIXED_CONVERT_EXPR, type, expr);
1113
1114     case COMPLEX_TYPE:
1115       return convert (type,
1116                       fold_build1 (REALPART_EXPR,
1117                                    TREE_TYPE (TREE_TYPE (expr)), expr));
1118
1119     default:
1120       error ("aggregate value used where a fixed-point was expected");
1121       return error_mark_node;
1122     }
1123 }