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             gcc_fallthrough ();
 168           CASE_MATHFN (ACOS)
 169           CASE_MATHFN (ACOSH)
 170           CASE_MATHFN (ASIN)
 171           CASE_MATHFN (ASINH)
 172           CASE_MATHFN (ATAN)
 173           CASE_MATHFN (ATANH)
 174           CASE_MATHFN (CBRT)
 175           CASE_MATHFN (COS)
 176           CASE_MATHFN (ERF)
 177           CASE_MATHFN (ERFC)
 178           CASE_MATHFN (LOG)
 179           CASE_MATHFN (LOG10)
 180           CASE_MATHFN (LOG2)
 181           CASE_MATHFN (LOG1P)
 182           CASE_MATHFN (SIN)
 183           CASE_MATHFN (TAN)
 184           CASE_MATHFN (TANH)
 185             /* The above functions are not safe to do this conversion.  */
 186             if (!flag_unsafe_math_optimizations)
 187               break;
 188             gcc_fallthrough ();
 189           CASE_MATHFN (SQRT)
 190           CASE_MATHFN (FABS)
 191           CASE_MATHFN (LOGB)
 192 #undef CASE_MATHFN
 193             {
 194               tree arg0 = strip_float_extensions (CALL_EXPR_ARG (expr, 0));
 195               tree newtype = type;
 196
 197               /* We have (outertype)sqrt((innertype)x).  Choose the wider mode from
 198                  the both as the safe type for operation.  */
 199               if (TYPE_PRECISION (TREE_TYPE (arg0)) > TYPE_PRECISION (type))
 200                 newtype = TREE_TYPE (arg0);
 201
 202               /* We consider to convert
 203
 204                      (T1) sqrtT2 ((T2) exprT3)
 205                  to
 206                      (T1) sqrtT4 ((T4) exprT3)
 207
 208                   , where T1 is TYPE, T2 is ITYPE, T3 is TREE_TYPE (ARG0),
 209                  and T4 is NEWTYPE.  All those types are of floating point types.
 210                  T4 (NEWTYPE) should be narrower than T2 (ITYPE). This conversion
 211                  is safe only if P1 >= P2*2+2, where P1 and P2 are precisions of
 212                  T2 and T4.  See the following URL for a reference:
 213                  http://stackoverflow.com/questions/9235456/determining-
 214                  floating-point-square-root
 215                  */
 216               if ((fcode == BUILT_IN_SQRT || fcode == BUILT_IN_SQRTL)
 217                   && !flag_unsafe_math_optimizations)
 218                 {
 219                   /* The following conversion is unsafe even the precision condition
 220                      below is satisfied:
 221
 222                      (float) sqrtl ((long double) double_val) -> (float) sqrt (double_val)
 223                     */
 224                   if (TYPE_MODE (type) != TYPE_MODE (newtype))
 225                     break;
 226
 227                   int p1 = REAL_MODE_FORMAT (TYPE_MODE (itype))->p;
 228                   int p2 = REAL_MODE_FORMAT (TYPE_MODE (newtype))->p;
 229                   if (p1 < p2 * 2 + 2)
 230                     break;
 231                 }
 232
 233               /* Be careful about integer to fp conversions.
 234                  These may overflow still.  */
 235               if (FLOAT_TYPE_P (TREE_TYPE (arg0))
 236                   && TYPE_PRECISION (newtype) < TYPE_PRECISION (itype)
 237                   && (TYPE_MODE (newtype) == TYPE_MODE (double_type_node)
 238                       || TYPE_MODE (newtype) == TYPE_MODE (float_type_node)))
 239                 {
 240                   tree fn = mathfn_built_in (newtype, fcode);
 241                   if (fn)
 242                     {
 243                       tree arg = convert_to_real_1 (newtype, arg0, fold_p);
 244                       expr = build_call_expr (fn, 1, arg);
 245                       if (newtype == type)
 246                         return expr;
 247                     }
 248                 }
 249             }
 250         default:
 251           break;
 252         }
 253     }
 254
 255   /* Propagate the cast into the operation.  */
 256   if (itype != type && FLOAT_TYPE_P (type))
 257     switch (TREE_CODE (expr))
 258       {
 259         /* Convert (float)-x into -(float)x.  This is safe for
 260            round-to-nearest rounding mode when the inner type is float.  */
 261         case ABS_EXPR:
 262         case NEGATE_EXPR:
 263           if (!flag_rounding_math
 264               && FLOAT_TYPE_P (itype)
 265               && TYPE_PRECISION (type) < TYPE_PRECISION (itype))
 266             {
 267               tree arg = convert_to_real_1 (type, TREE_OPERAND (expr, 0),
 268                                             fold_p);
 269               return build1 (TREE_CODE (expr), type, arg);
 270             }
 271           break;
 272         /* Convert (outertype)((innertype0)a+(innertype1)b)
 273            into ((newtype)a+(newtype)b) where newtype
 274            is the widest mode from all of these.  */
 275         case PLUS_EXPR:
 276         case MINUS_EXPR:
 277         case MULT_EXPR:
 278         case RDIV_EXPR:
 279            {
 280              tree arg0 = strip_float_extensions (TREE_OPERAND (expr, 0));
 281              tree arg1 = strip_float_extensions (TREE_OPERAND (expr, 1));
 282
 283              if (FLOAT_TYPE_P (TREE_TYPE (arg0))
 284                  && FLOAT_TYPE_P (TREE_TYPE (arg1))
 285                  && DECIMAL_FLOAT_TYPE_P (itype) == DECIMAL_FLOAT_TYPE_P (type))
 286                {
 287                   tree newtype = type;
 288
 289                   if (TYPE_MODE (TREE_TYPE (arg0)) == SDmode
 290                       || TYPE_MODE (TREE_TYPE (arg1)) == SDmode
 291                       || TYPE_MODE (type) == SDmode)
 292                     newtype = dfloat32_type_node;
 293                   if (TYPE_MODE (TREE_TYPE (arg0)) == DDmode
 294                       || TYPE_MODE (TREE_TYPE (arg1)) == DDmode
 295                       || TYPE_MODE (type) == DDmode)
 296                     newtype = dfloat64_type_node;
 297                   if (TYPE_MODE (TREE_TYPE (arg0)) == TDmode
 298                       || TYPE_MODE (TREE_TYPE (arg1)) == TDmode
 299                       || TYPE_MODE (type) == TDmode)
 300                     newtype = dfloat128_type_node;
 301                   if (newtype == dfloat32_type_node
 302                       || newtype == dfloat64_type_node
 303                       || newtype == dfloat128_type_node)
 304                     {
 305                       expr = build2 (TREE_CODE (expr), newtype,
 306                                      convert_to_real_1 (newtype, arg0,
 307                                                         fold_p),
 308                                      convert_to_real_1 (newtype, arg1,
 309                                                         fold_p));
 310                       if (newtype == type)
 311                         return expr;
 312                       break;
 313                     }
 314
 315                   if (TYPE_PRECISION (TREE_TYPE (arg0)) > TYPE_PRECISION (newtype))
 316                     newtype = TREE_TYPE (arg0);
 317                   if (TYPE_PRECISION (TREE_TYPE (arg1)) > TYPE_PRECISION (newtype))
 318                     newtype = TREE_TYPE (arg1);
 319                   /* Sometimes this transformation is safe (cannot
 320                      change results through affecting double rounding
 321                      cases) and sometimes it is not.  If NEWTYPE is
 322                      wider than TYPE, e.g. (float)((long double)double
 323                      + (long double)double) converted to
 324                      (float)(double + double), the transformation is
 325                      unsafe regardless of the details of the types
 326                      involved; double rounding can arise if the result
 327                      of NEWTYPE arithmetic is a NEWTYPE value half way
 328                      between two representable TYPE values but the
 329                      exact value is sufficiently different (in the
 330                      right direction) for this difference to be
 331                      visible in ITYPE arithmetic.  If NEWTYPE is the
 332                      same as TYPE, however, the transformation may be
 333                      safe depending on the types involved: it is safe
 334                      if the ITYPE has strictly more than twice as many
 335                      mantissa bits as TYPE, can represent infinities
 336                      and NaNs if the TYPE can, and has sufficient
 337                      exponent range for the product or ratio of two
 338                      values representable in the TYPE to be within the
 339                      range of normal values of ITYPE.  */
 340                   if (TYPE_PRECISION (newtype) < TYPE_PRECISION (itype)
 341                       && (flag_unsafe_math_optimizations
 342                           || (TYPE_PRECISION (newtype) == TYPE_PRECISION (type)
 343                               && real_can_shorten_arithmetic (TYPE_MODE (itype),
 344                                                               TYPE_MODE (type))
 345                               && !excess_precision_type (newtype))))
 346                     {
 347                       expr = build2 (TREE_CODE (expr), newtype,
 348                                      convert_to_real_1 (newtype, arg0,
 349                                                         fold_p),
 350                                      convert_to_real_1 (newtype, arg1,
 351                                                         fold_p));
 352                       if (newtype == type)
 353                         return expr;
 354                     }
 355                }
 356            }
 357           break;
 358         default:
 359           break;
 360       }
 361
 362   switch (TREE_CODE (TREE_TYPE (expr)))
 363     {
 364     case REAL_TYPE:
 365       /* Ignore the conversion if we don't need to store intermediate
 366          results and neither type is a decimal float.  */
 367       return build1_loc (loc,
 368                          (flag_float_store
 369                           || DECIMAL_FLOAT_TYPE_P (type)
 370                           || DECIMAL_FLOAT_TYPE_P (itype))
 371                          ? CONVERT_EXPR : NOP_EXPR, type, expr);
 372
 373     case INTEGER_TYPE:
 374     case ENUMERAL_TYPE:
 375     case BOOLEAN_TYPE:
 376       return build1 (FLOAT_EXPR, type, expr);
 377
 378     case FIXED_POINT_TYPE:
 379       return build1 (FIXED_CONVERT_EXPR, type, expr);
 380
 381     case COMPLEX_TYPE:
 382       return convert (type,
 383                       maybe_fold_build1_loc (fold_p, loc, REALPART_EXPR,
 384                                              TREE_TYPE (TREE_TYPE (expr)),
 385                                              expr));
 386
 387     case POINTER_TYPE:
 388     case REFERENCE_TYPE:
 389       error ("pointer value used where a floating point value was expected");
 390       return convert_to_real_1 (type, integer_zero_node, fold_p);
 391
 392     default:
 393       error ("aggregate value used where a float was expected");
 394       return convert_to_real_1 (type, integer_zero_node, fold_p);
 395     }
 396 }
 397
 398 /* A wrapper around convert_to_real_1 that always folds the
 399    expression.  */
 400
 401 tree
 402 convert_to_real (tree type, tree expr)
 403 {
 404   return convert_to_real_1 (type, expr, true);
 405 }
 406
 407 /* A wrapper around convert_to_real_1 that only folds the
 408    expression if DOFOLD, or if it is CONSTANT_CLASS_P.  */
 409
 410 tree
 411 convert_to_real_maybe_fold (tree type, tree expr, bool dofold)
 412 {
 413   return convert_to_real_1 (type, expr, dofold || CONSTANT_CLASS_P (expr));
 414 }
 415
 416 /* Convert EXPR to some integer (or enum) type TYPE.
 417
 418    EXPR must be pointer, integer, discrete (enum, char, or bool), float,
 419    fixed-point or vector; in other cases error is called.
 420
 421    If DOFOLD is TRUE, we try to simplify newly-created patterns by folding.
 422
 423    The result of this is always supposed to be a newly created tree node
 424    not in use in any existing structure.  */
 425
 426 static tree
 427 convert_to_integer_1 (tree type, tree expr, bool dofold)
 428 {
 429   enum tree_code ex_form = TREE_CODE (expr);
 430   tree intype = TREE_TYPE (expr);
 431   unsigned int inprec = element_precision (intype);
 432   unsigned int outprec = element_precision (type);
 433   location_t loc = EXPR_LOCATION (expr);
 434
 435   /* An INTEGER_TYPE cannot be incomplete, but an ENUMERAL_TYPE can
 436      be.  Consider `enum E = { a, b = (enum E) 3 };'.  */
 437   if (!COMPLETE_TYPE_P (type))
 438     {
 439       error ("conversion to incomplete type");
 440       return error_mark_node;
 441     }
 442
 443   if (ex_form == COMPOUND_EXPR)
 444     {
 445       tree t = convert_to_integer_1 (type, TREE_OPERAND (expr, 1), dofold);
 446       if (t == TREE_OPERAND (expr, 1))
 447         return expr;
 448       return build2_loc (EXPR_LOCATION (expr), COMPOUND_EXPR, TREE_TYPE (t),
 449                          TREE_OPERAND (expr, 0), t);
 450     }
 451
 452   /* Convert e.g. (long)round(d) -> lround(d).  */
 453   /* If we're converting to char, we may encounter differing behavior
 454      between converting from double->char vs double->long->char.
 455      We're in "undefined" territory but we prefer to be conservative,
 456      so only proceed in "unsafe" math mode.  */
 457   if (optimize
 458       && (flag_unsafe_math_optimizations
 459           || (long_integer_type_node
 460               && outprec >= TYPE_PRECISION (long_integer_type_node))))
 461     {
 462       tree s_expr = strip_float_extensions (expr);
 463       tree s_intype = TREE_TYPE (s_expr);
 464       const enum built_in_function fcode = builtin_mathfn_code (s_expr);
 465       tree fn = 0;
 466
 467       switch (fcode)
 468         {
 469         CASE_FLT_FN (BUILT_IN_CEIL):
 470           /* Only convert in ISO C99 mode.  */
 471           if (!targetm.libc_has_function (function_c99_misc))
 472             break;
 473           if (outprec < TYPE_PRECISION (integer_type_node)
 474               || (outprec == TYPE_PRECISION (integer_type_node)
 475                   && !TYPE_UNSIGNED (type)))
 476             fn = mathfn_built_in (s_intype, BUILT_IN_ICEIL);
 477           else if (outprec == TYPE_PRECISION (long_integer_type_node)
 478                    && !TYPE_UNSIGNED (type))
 479             fn = mathfn_built_in (s_intype, BUILT_IN_LCEIL);
 480           else if (outprec == TYPE_PRECISION (long_long_integer_type_node)
 481                    && !TYPE_UNSIGNED (type))
 482             fn = mathfn_built_in (s_intype, BUILT_IN_LLCEIL);
 483           break;
 484
 485         CASE_FLT_FN (BUILT_IN_FLOOR):
 486           /* Only convert in ISO C99 mode.  */
 487           if (!targetm.libc_has_function (function_c99_misc))
 488             break;
 489           if (outprec < TYPE_PRECISION (integer_type_node)
 490               || (outprec == TYPE_PRECISION (integer_type_node)
 491                   && !TYPE_UNSIGNED (type)))
 492             fn = mathfn_built_in (s_intype, BUILT_IN_IFLOOR);
 493           else if (outprec == TYPE_PRECISION (long_integer_type_node)
 494                    && !TYPE_UNSIGNED (type))
 495             fn = mathfn_built_in (s_intype, BUILT_IN_LFLOOR);
 496           else if (outprec == TYPE_PRECISION (long_long_integer_type_node)
 497                    && !TYPE_UNSIGNED (type))
 498             fn = mathfn_built_in (s_intype, BUILT_IN_LLFLOOR);
 499           break;
 500
 501         CASE_FLT_FN (BUILT_IN_ROUND):
 502           /* Only convert in ISO C99 mode and with -fno-math-errno.  */
 503           if (!targetm.libc_has_function (function_c99_misc) || flag_errno_math)
 504             break;
 505           if (outprec < TYPE_PRECISION (integer_type_node)
 506               || (outprec == TYPE_PRECISION (integer_type_node)
 507                   && !TYPE_UNSIGNED (type)))
 508             fn = mathfn_built_in (s_intype, BUILT_IN_IROUND);
 509           else if (outprec == TYPE_PRECISION (long_integer_type_node)
 510                    && !TYPE_UNSIGNED (type))
 511             fn = mathfn_built_in (s_intype, BUILT_IN_LROUND);
 512           else if (outprec == TYPE_PRECISION (long_long_integer_type_node)
 513                    && !TYPE_UNSIGNED (type))
 514             fn = mathfn_built_in (s_intype, BUILT_IN_LLROUND);
 515           break;
 516
 517         CASE_FLT_FN (BUILT_IN_NEARBYINT):
 518           /* Only convert nearbyint* if we can ignore math exceptions.  */
 519           if (flag_trapping_math)
 520             break;
 521           gcc_fallthrough ();
 522         CASE_FLT_FN (BUILT_IN_RINT):
 523           /* Only convert in ISO C99 mode and with -fno-math-errno.  */
 524           if (!targetm.libc_has_function (function_c99_misc) || flag_errno_math)
 525             break;
 526           if (outprec < TYPE_PRECISION (integer_type_node)
 527               || (outprec == TYPE_PRECISION (integer_type_node)
 528                   && !TYPE_UNSIGNED (type)))
 529             fn = mathfn_built_in (s_intype, BUILT_IN_IRINT);
 530           else if (outprec == TYPE_PRECISION (long_integer_type_node)
 531                    && !TYPE_UNSIGNED (type))
 532             fn = mathfn_built_in (s_intype, BUILT_IN_LRINT);
 533           else if (outprec == TYPE_PRECISION (long_long_integer_type_node)
 534                    && !TYPE_UNSIGNED (type))
 535             fn = mathfn_built_in (s_intype, BUILT_IN_LLRINT);
 536           break;
 537
 538         CASE_FLT_FN (BUILT_IN_TRUNC):
 539           return convert_to_integer_1 (type, CALL_EXPR_ARG (s_expr, 0), dofold);
 540
 541         default:
 542           break;
 543         }
 544
 545       if (fn)
 546         {
 547           tree newexpr = build_call_expr (fn, 1, CALL_EXPR_ARG (s_expr, 0));
 548           return convert_to_integer_1 (type, newexpr, dofold);
 549         }
 550     }
 551
 552   /* Convert (int)logb(d) -> ilogb(d).  */
 553   if (optimize
 554       && flag_unsafe_math_optimizations
 555       && !flag_trapping_math && !flag_errno_math && flag_finite_math_only
 556       && integer_type_node
 557       && (outprec > TYPE_PRECISION (integer_type_node)
 558           || (outprec == TYPE_PRECISION (integer_type_node)
 559               && !TYPE_UNSIGNED (type))))
 560     {
 561       tree s_expr = strip_float_extensions (expr);
 562       tree s_intype = TREE_TYPE (s_expr);
 563       const enum built_in_function fcode = builtin_mathfn_code (s_expr);
 564       tree fn = 0;
 565
 566       switch (fcode)
 567         {
 568         CASE_FLT_FN (BUILT_IN_LOGB):
 569           fn = mathfn_built_in (s_intype, BUILT_IN_ILOGB);
 570           break;
 571
 572         default:
 573           break;
 574         }
 575
 576       if (fn)
 577         {
 578           tree newexpr = build_call_expr (fn, 1, CALL_EXPR_ARG (s_expr, 0));
 579           return convert_to_integer_1 (type, newexpr, dofold);
 580         }
 581     }
 582
 583   switch (TREE_CODE (intype))
 584     {
 585     case POINTER_TYPE:
 586     case REFERENCE_TYPE:
 587       if (integer_zerop (expr))
 588         return build_int_cst (type, 0);
 589
 590       /* Convert to an unsigned integer of the correct width first, and from
 591          there widen/truncate to the required type.  Some targets support the
 592          coexistence of multiple valid pointer sizes, so fetch the one we need
 593          from the type.  */
 594       if (!dofold)
 595         return build1 (CONVERT_EXPR, type, expr);
 596       expr = fold_build1 (CONVERT_EXPR,
 597                           lang_hooks.types.type_for_size
 598                             (TYPE_PRECISION (intype), 0),
 599                           expr);
 600       return fold_convert (type, expr);
 601
 602     case INTEGER_TYPE:
 603     case ENUMERAL_TYPE:
 604     case BOOLEAN_TYPE:
 605     case OFFSET_TYPE:
 606       /* If this is a logical operation, which just returns 0 or 1, we can
 607          change the type of the expression.  */
 608
 609       if (TREE_CODE_CLASS (ex_form) == tcc_comparison)
 610         {
 611           expr = copy_node (expr);
 612           TREE_TYPE (expr) = type;
 613           return expr;
 614         }
 615
 616       /* If we are widening the type, put in an explicit conversion.
 617          Similarly if we are not changing the width.  After this, we know
 618          we are truncating EXPR.  */
 619
 620       else if (outprec >= inprec)
 621         {
 622           enum tree_code code;
 623
 624           /* If the precision of the EXPR's type is K bits and the
 625              destination mode has more bits, and the sign is changing,
 626              it is not safe to use a NOP_EXPR.  For example, suppose
 627              that EXPR's type is a 3-bit unsigned integer type, the
 628              TYPE is a 3-bit signed integer type, and the machine mode
 629              for the types is 8-bit QImode.  In that case, the
 630              conversion necessitates an explicit sign-extension.  In
 631              the signed-to-unsigned case the high-order bits have to
 632              be cleared.  */
 633           if (TYPE_UNSIGNED (type) != TYPE_UNSIGNED (TREE_TYPE (expr))
 634               && (TYPE_PRECISION (TREE_TYPE (expr))
 635                   != GET_MODE_PRECISION (TYPE_MODE (TREE_TYPE (expr)))))
 636             code = CONVERT_EXPR;
 637           else
 638             code = NOP_EXPR;
 639
 640           return maybe_fold_build1_loc (dofold, loc, code, type, expr);
 641         }
 642
 643       /* If TYPE is an enumeral type or a type with a precision less
 644          than the number of bits in its mode, do the conversion to the
 645          type corresponding to its mode, then do a nop conversion
 646          to TYPE.  */
 647       else if (TREE_CODE (type) == ENUMERAL_TYPE
 648                || outprec != GET_MODE_PRECISION (TYPE_MODE (type)))
 649         return build1 (NOP_EXPR, type,
 650                        convert (lang_hooks.types.type_for_mode
 651                                 (TYPE_MODE (type), TYPE_UNSIGNED (type)),
 652                                 expr));
 653
 654       /* Here detect when we can distribute the truncation down past some
 655          arithmetic.  For example, if adding two longs and converting to an
 656          int, we can equally well convert both to ints and then add.
 657          For the operations handled here, such truncation distribution
 658          is always safe.
 659          It is desirable in these cases:
 660          1) when truncating down to full-word from a larger size
 661          2) when truncating takes no work.
 662          3) when at least one operand of the arithmetic has been extended
 663          (as by C's default conversions).  In this case we need two conversions
 664          if we do the arithmetic as already requested, so we might as well
 665          truncate both and then combine.  Perhaps that way we need only one.
 666
 667          Note that in general we cannot do the arithmetic in a type
 668          shorter than the desired result of conversion, even if the operands
 669          are both extended from a shorter type, because they might overflow
 670          if combined in that type.  The exceptions to this--the times when
 671          two narrow values can be combined in their narrow type even to
 672          make a wider result--are handled by "shorten" in build_binary_op.  */
 673
 674       if (dofold)
 675         switch (ex_form)
 676           {
 677           case RSHIFT_EXPR:
 678             /* We can pass truncation down through right shifting
 679                when the shift count is a nonpositive constant.  */
 680             if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST
 681                 && tree_int_cst_sgn (TREE_OPERAND (expr, 1)) <= 0)
 682               goto trunc1;
 683             break;
 684
 685           case LSHIFT_EXPR:
 686             /* We can pass truncation down through left shifting
 687                when the shift count is a nonnegative constant and
 688                the target type is unsigned.  */
 689             if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST
 690                 && tree_int_cst_sgn (TREE_OPERAND (expr, 1)) >= 0
 691                 && TYPE_UNSIGNED (type)
 692                 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
 693               {
 694                 /* If shift count is less than the width of the truncated type,
 695                    really shift.  */
 696                 if (tree_int_cst_lt (TREE_OPERAND (expr, 1), TYPE_SIZE (type)))
 697                   /* In this case, shifting is like multiplication.  */
 698                   goto trunc1;
 699                 else
 700                   {
 701                     /* If it is >= that width, result is zero.
 702                        Handling this with trunc1 would give the wrong result:
 703                        (int) ((long long) a << 32) is well defined (as 0)
 704                        but (int) a << 32 is undefined and would get a
 705                        warning.  */
 706
 707                     tree t = build_int_cst (type, 0);
 708
 709                     /* If the original expression had side-effects, we must
 710                        preserve it.  */
 711                     if (TREE_SIDE_EFFECTS (expr))
 712                       return build2 (COMPOUND_EXPR, type, expr, t);
 713                     else
 714                       return t;
 715                   }
 716               }
 717             break;
 718
 719           case TRUNC_DIV_EXPR:
 720             {
 721               tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
 722               tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
 723
 724               /* Don't distribute unless the output precision is at least as
 725                  big as the actual inputs and it has the same signedness.  */
 726               if (outprec >= TYPE_PRECISION (TREE_TYPE (arg0))
 727                   && outprec >= TYPE_PRECISION (TREE_TYPE (arg1))
 728                   /* If signedness of arg0 and arg1 don't match,
 729                      we can't necessarily find a type to compare them in.  */
 730                   && (TYPE_UNSIGNED (TREE_TYPE (arg0))
 731                       == TYPE_UNSIGNED (TREE_TYPE (arg1)))
 732                   /* Do not change the sign of the division.  */
 733                   && (TYPE_UNSIGNED (TREE_TYPE (expr))
 734                       == TYPE_UNSIGNED (TREE_TYPE (arg0)))
 735                   /* Either require unsigned division or a division by
 736                      a constant that is not -1.  */
 737                   && (TYPE_UNSIGNED (TREE_TYPE (arg0))
 738                       || (TREE_CODE (arg1) == INTEGER_CST
 739                           && !integer_all_onesp (arg1))))
 740                 goto trunc1;
 741               break;
 742             }
 743
 744           case MAX_EXPR:
 745           case MIN_EXPR:
 746           case MULT_EXPR:
 747             {
 748               tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
 749               tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
 750
 751               /* Don't distribute unless the output precision is at least as
 752                  big as the actual inputs.  Otherwise, the comparison of the
 753                  truncated values will be wrong.  */
 754               if (outprec >= TYPE_PRECISION (TREE_TYPE (arg0))
 755                   && outprec >= TYPE_PRECISION (TREE_TYPE (arg1))
 756                   /* If signedness of arg0 and arg1 don't match,
 757                      we can't necessarily find a type to compare them in.  */
 758                   && (TYPE_UNSIGNED (TREE_TYPE (arg0))
 759                       == TYPE_UNSIGNED (TREE_TYPE (arg1))))
 760                 goto trunc1;
 761               break;
 762             }
 763
 764           case PLUS_EXPR:
 765           case MINUS_EXPR:
 766           case BIT_AND_EXPR:
 767           case BIT_IOR_EXPR:
 768           case BIT_XOR_EXPR:
 769           trunc1:
 770             {
 771               tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
 772               tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
 773
 774               /* Do not try to narrow operands of pointer subtraction;
 775                  that will interfere with other folding.  */
 776               if (ex_form == MINUS_EXPR
 777                   && CONVERT_EXPR_P (arg0)
 778                   && CONVERT_EXPR_P (arg1)
 779                   && POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (arg0, 0)))
 780                   && POINTER_TYPE_P (TREE_TYPE (TREE_OPERAND (arg1, 0))))
 781                 break;
 782
 783               if (outprec >= BITS_PER_WORD
 784                   || TRULY_NOOP_TRUNCATION (outprec, inprec)
 785                   || inprec > TYPE_PRECISION (TREE_TYPE (arg0))
 786                   || inprec > TYPE_PRECISION (TREE_TYPE (arg1)))
 787                 {
 788                   /* Do the arithmetic in type TYPEX,
 789                      then convert result to TYPE.  */
 790                   tree typex = type;
 791
 792                   /* Can't do arithmetic in enumeral types
 793                      so use an integer type that will hold the values.  */
 794                   if (TREE_CODE (typex) == ENUMERAL_TYPE)
 795                     typex
 796                       = lang_hooks.types.type_for_size (TYPE_PRECISION (typex),
 797                                                         TYPE_UNSIGNED (typex));
 798
 799                   /* But now perhaps TYPEX is as wide as INPREC.
 800                      In that case, do nothing special here.
 801                      (Otherwise would recurse infinitely in convert.  */
 802                   if (TYPE_PRECISION (typex) != inprec)
 803                     {
 804                       /* Don't do unsigned arithmetic where signed was wanted,
 805                          or vice versa.
 806                          Exception: if both of the original operands were
 807                          unsigned then we can safely do the work as unsigned.
 808                          Exception: shift operations take their type solely
 809                          from the first argument.
 810                          Exception: the LSHIFT_EXPR case above requires that
 811                          we perform this operation unsigned lest we produce
 812                          signed-overflow undefinedness.
 813                          And we may need to do it as unsigned
 814                          if we truncate to the original size.  */
 815                       if (TYPE_UNSIGNED (TREE_TYPE (expr))
 816                           || (TYPE_UNSIGNED (TREE_TYPE (arg0))
 817                               && (TYPE_UNSIGNED (TREE_TYPE (arg1))
 818                                   || ex_form == LSHIFT_EXPR
 819                                   || ex_form == RSHIFT_EXPR
 820                                   || ex_form == LROTATE_EXPR
 821                                   || ex_form == RROTATE_EXPR))
 822                           || ex_form == LSHIFT_EXPR
 823                           /* If we have !flag_wrapv, and either ARG0 or
 824                              ARG1 is of a signed type, we have to do
 825                              PLUS_EXPR, MINUS_EXPR or MULT_EXPR in an unsigned
 826                              type in case the operation in outprec precision
 827                              could overflow.  Otherwise, we would introduce
 828                              signed-overflow undefinedness.  */
 829                           || ((!TYPE_OVERFLOW_WRAPS (TREE_TYPE (arg0))
 830                                || !TYPE_OVERFLOW_WRAPS (TREE_TYPE (arg1)))
 831                               && ((TYPE_PRECISION (TREE_TYPE (arg0)) * 2u
 832                                    > outprec)
 833                                   || (TYPE_PRECISION (TREE_TYPE (arg1)) * 2u
 834                                       > outprec))
 835                               && (ex_form == PLUS_EXPR
 836                                   || ex_form == MINUS_EXPR
 837                                   || ex_form == MULT_EXPR)))
 838                         {
 839                           if (!TYPE_UNSIGNED (typex))
 840                             typex = unsigned_type_for (typex);
 841                         }
 842                       else
 843                         {
 844                           if (TYPE_UNSIGNED (typex))
 845                             typex = signed_type_for (typex);
 846                         }
 847                       /* We should do away with all this once we have a proper
 848                          type promotion/demotion pass, see PR45397.  */
 849                       expr = maybe_fold_build2_loc (dofold, loc, ex_form, typex,
 850                                                     convert (typex, arg0),
 851                                                     convert (typex, arg1));
 852                       return convert (type, expr);
 853                     }
 854                 }
 855             }
 856             break;
 857
 858           case NEGATE_EXPR:
 859           case BIT_NOT_EXPR:
 860             /* This is not correct for ABS_EXPR,
 861                since we must test the sign before truncation.  */
 862             {
 863               /* Do the arithmetic in type TYPEX,
 864                  then convert result to TYPE.  */
 865               tree typex = type;
 866
 867               /* Can't do arithmetic in enumeral types
 868                  so use an integer type that will hold the values.  */
 869               if (TREE_CODE (typex) == ENUMERAL_TYPE)
 870                 typex
 871                   = lang_hooks.types.type_for_size (TYPE_PRECISION (typex),
 872                                                     TYPE_UNSIGNED (typex));
 873
 874               if (!TYPE_UNSIGNED (typex))
 875                 typex = unsigned_type_for (typex);
 876               return convert (type,
 877                               fold_build1 (ex_form, typex,
 878                                            convert (typex,
 879                                                     TREE_OPERAND (expr, 0))));
 880             }
 881
 882           CASE_CONVERT:
 883             /* Don't introduce a "can't convert between vector values of
 884                different size" error.  */
 885             if (TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == VECTOR_TYPE
 886                 && (GET_MODE_SIZE (TYPE_MODE
 887                                    (TREE_TYPE (TREE_OPERAND (expr, 0))))
 888                     != GET_MODE_SIZE (TYPE_MODE (type))))
 889               break;
 890             /* If truncating after truncating, might as well do all at once.
 891                If truncating after extending, we may get rid of wasted work.  */
 892             return convert (type, get_unwidened (TREE_OPERAND (expr, 0), type));
 893
 894           case COND_EXPR:
 895             /* It is sometimes worthwhile to push the narrowing down through
 896                the conditional and never loses.  A COND_EXPR may have a throw
 897                as one operand, which then has void type.  Just leave void
 898                operands as they are.  */
 899             return
 900               fold_build3 (COND_EXPR, type, TREE_OPERAND (expr, 0),
 901                            VOID_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 1)))
 902                            ? TREE_OPERAND (expr, 1)
 903                            : convert (type, TREE_OPERAND (expr, 1)),
 904                            VOID_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 2)))
 905                            ? TREE_OPERAND (expr, 2)
 906                            : convert (type, TREE_OPERAND (expr, 2)));
 907
 908           default:
 909             break;
 910           }
 911
 912       /* When parsing long initializers, we might end up with a lot of casts.
 913          Shortcut this.  */
 914       if (TREE_CODE (expr) == INTEGER_CST)
 915         return fold_convert (type, expr);
 916       return build1 (CONVERT_EXPR, type, expr);
 917
 918     case REAL_TYPE:
 919       if (flag_sanitize & SANITIZE_FLOAT_CAST
 920           && do_ubsan_in_current_function ())
 921         {
 922           expr = save_expr (expr);
 923           tree check = ubsan_instrument_float_cast (loc, type, expr);
 924           expr = build1 (FIX_TRUNC_EXPR, type, expr);
 925           if (check == NULL_TREE)
 926             return expr;
 927           return maybe_fold_build2_loc (dofold, loc, COMPOUND_EXPR,
 928                                         TREE_TYPE (expr), check, expr);
 929         }
 930       else
 931         return build1 (FIX_TRUNC_EXPR, type, expr);
 932
 933     case FIXED_POINT_TYPE:
 934       return build1 (FIXED_CONVERT_EXPR, type, expr);
 935
 936     case COMPLEX_TYPE:
 937       expr = maybe_fold_build1_loc (dofold, loc, REALPART_EXPR,
 938                                     TREE_TYPE (TREE_TYPE (expr)), expr);
 939       return convert (type, expr);
 940
 941     case VECTOR_TYPE:
 942       if (!tree_int_cst_equal (TYPE_SIZE (type), TYPE_SIZE (TREE_TYPE (expr))))
 943         {
 944           error ("can%'t convert a vector of type %qT"
 945                  " to type %qT which has different size",
 946                  TREE_TYPE (expr), type);
 947           return error_mark_node;
 948         }
 949       return build1 (VIEW_CONVERT_EXPR, type, expr);
 950
 951     default:
 952       error ("aggregate value used where an integer was expected");
 953       return convert (type, integer_zero_node);
 954     }
 955 }
 956
 957 /* Convert EXPR to some integer (or enum) type TYPE.
 958
 959    EXPR must be pointer, integer, discrete (enum, char, or bool), float,
 960    fixed-point or vector; in other cases error is called.
 961
 962    The result of this is always supposed to be a newly created tree node
 963    not in use in any existing structure.  */
 964
 965 tree
 966 convert_to_integer (tree type, tree expr)
 967 {
 968   return convert_to_integer_1 (type, expr, true);
 969 }
 970
 971 /* A wrapper around convert_to_complex_1 that only folds the
 972    expression if DOFOLD, or if it is CONSTANT_CLASS_P.  */
 973
 974 tree
 975 convert_to_integer_maybe_fold (tree type, tree expr, bool dofold)
 976 {
 977   return convert_to_integer_1 (type, expr, dofold || CONSTANT_CLASS_P (expr));
 978 }
 979
 980 /* Convert EXPR to the complex type TYPE in the usual ways.  If FOLD_P is
 981    true, try to fold the expression.  */
 982
 983 static tree
 984 convert_to_complex_1 (tree type, tree expr, bool fold_p)
 985 {
 986   location_t loc = EXPR_LOCATION (expr);
 987   tree subtype = TREE_TYPE (type);
 988
 989   switch (TREE_CODE (TREE_TYPE (expr)))
 990     {
 991     case REAL_TYPE:
 992     case FIXED_POINT_TYPE:
 993     case INTEGER_TYPE:
 994     case ENUMERAL_TYPE:
 995     case BOOLEAN_TYPE:
 996       return build2 (COMPLEX_EXPR, type, convert (subtype, expr),
 997                      convert (subtype, integer_zero_node));
 998
 999     case COMPLEX_TYPE:
1000       {
1001         tree elt_type = TREE_TYPE (TREE_TYPE (expr));
1002
1003         if (TYPE_MAIN_VARIANT (elt_type) == TYPE_MAIN_VARIANT (subtype))
1004           return expr;
1005         else if (TREE_CODE (expr) == COMPOUND_EXPR)
1006           {
1007             tree t = convert_to_complex_1 (type, TREE_OPERAND (expr, 1),
1008                                            fold_p);
1009             if (t == TREE_OPERAND (expr, 1))
1010               return expr;
1011             return build2_loc (EXPR_LOCATION (expr), COMPOUND_EXPR,
1012                                TREE_TYPE (t), TREE_OPERAND (expr, 0), t);
1013           }
1014         else if (TREE_CODE (expr) == COMPLEX_EXPR)
1015           return maybe_fold_build2_loc (fold_p, loc, COMPLEX_EXPR, type,
1016                                         convert (subtype,
1017                                                  TREE_OPERAND (expr, 0)),
1018                                         convert (subtype,
1019                                                  TREE_OPERAND (expr, 1)));
1020         else
1021           {
1022             expr = save_expr (expr);
1023             tree realp = maybe_fold_build1_loc (fold_p, loc, REALPART_EXPR,
1024                                                 TREE_TYPE (TREE_TYPE (expr)),
1025                                                 expr);
1026             tree imagp = maybe_fold_build1_loc (fold_p, loc, IMAGPART_EXPR,
1027                                                 TREE_TYPE (TREE_TYPE (expr)),
1028                                                 expr);
1029             return maybe_fold_build2_loc (fold_p, loc, COMPLEX_EXPR, type,
1030                                           convert (subtype, realp),
1031                                           convert (subtype, imagp));
1032           }
1033       }
1034
1035     case POINTER_TYPE:
1036     case REFERENCE_TYPE:
1037       error ("pointer value used where a complex was expected");
1038       return convert_to_complex_1 (type, integer_zero_node, fold_p);
1039
1040     default:
1041       error ("aggregate value used where a complex was expected");
1042       return convert_to_complex_1 (type, integer_zero_node, fold_p);
1043     }
1044 }
1045
1046 /* A wrapper around convert_to_complex_1 that always folds the
1047    expression.  */
1048
1049 tree
1050 convert_to_complex (tree type, tree expr)
1051 {
1052   return convert_to_complex_1 (type, expr, true);
1053 }
1054
1055 /* A wrapper around convert_to_complex_1 that only folds the
1056    expression if DOFOLD, or if it is CONSTANT_CLASS_P.  */
1057
1058 tree
1059 convert_to_complex_maybe_fold (tree type, tree expr, bool dofold)
1060 {
1061   return convert_to_complex_1 (type, expr, dofold || CONSTANT_CLASS_P (expr));
1062 }
1063
1064 /* Convert EXPR to the vector type TYPE in the usual ways.  */
1065
1066 tree
1067 convert_to_vector (tree type, tree expr)
1068 {
1069   switch (TREE_CODE (TREE_TYPE (expr)))
1070     {
1071     case INTEGER_TYPE:
1072     case VECTOR_TYPE:
1073       if (!tree_int_cst_equal (TYPE_SIZE (type), TYPE_SIZE (TREE_TYPE (expr))))
1074         {
1075           error ("can%'t convert a value of type %qT"
1076                  " to vector type %qT which has different size",
1077                  TREE_TYPE (expr), type);
1078           return error_mark_node;
1079         }
1080       return build1 (VIEW_CONVERT_EXPR, type, expr);
1081
1082     default:
1083       error ("can%'t convert value to a vector");
1084       return error_mark_node;
1085     }
1086 }
1087
1088 /* Convert EXPR to some fixed-point type TYPE.
1089
1090    EXPR must be fixed-point, float, integer, or enumeral;
1091    in other cases error is called.  */
1092
1093 tree
1094 convert_to_fixed (tree type, tree expr)
1095 {
1096   if (integer_zerop (expr))
1097     {
1098       tree fixed_zero_node = build_fixed (type, FCONST0 (TYPE_MODE (type)));
1099       return fixed_zero_node;
1100     }
1101   else if (integer_onep (expr) && ALL_SCALAR_ACCUM_MODE_P (TYPE_MODE (type)))
1102     {
1103       tree fixed_one_node = build_fixed (type, FCONST1 (TYPE_MODE (type)));
1104       return fixed_one_node;
1105     }
1106
1107   switch (TREE_CODE (TREE_TYPE (expr)))
1108     {
1109     case FIXED_POINT_TYPE:
1110     case INTEGER_TYPE:
1111     case ENUMERAL_TYPE:
1112     case BOOLEAN_TYPE:
1113     case REAL_TYPE:
1114       return build1 (FIXED_CONVERT_EXPR, type, expr);
1115
1116     case COMPLEX_TYPE:
1117       return convert (type,
1118                       fold_build1 (REALPART_EXPR,
1119                                    TREE_TYPE (TREE_TYPE (expr)), expr));
1120
1121     default:
1122       error ("aggregate value used where a fixed-point was expected");
1123       return error_mark_node;
1124     }
1125 }