gcc/real.h

   1 /* Definitions of floating-point access for GNU compiler.
   2    Copyright (C) 1989-2023 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 #ifndef GCC_REAL_H
  21 #define GCC_REAL_H
  22
  23 /* An expanded form of the represented number.  */
  24
  25 /* Enumerate the special cases of numbers that we encounter.  */
  26 enum real_value_class {
  27   rvc_zero,
  28   rvc_normal,
  29   rvc_inf,
  30   rvc_nan
  31 };
  32
  33 #define SIGNIFICAND_BITS        (128 + HOST_BITS_PER_LONG)
  34 #define EXP_BITS                (32 - 6)
  35 #define MAX_EXP                 ((1 << (EXP_BITS - 1)) - 1)
  36 #define SIGSZ                   (SIGNIFICAND_BITS / HOST_BITS_PER_LONG)
  37 #define SIG_MSB                 ((unsigned long)1 << (HOST_BITS_PER_LONG - 1))
  38
  39 struct GTY(()) real_value {
  40   /* Use the same underlying type for all bit-fields, so as to make
  41      sure they're packed together, otherwise REAL_VALUE_TYPE_SIZE will
  42      be miscomputed.  */
  43   unsigned int /* ENUM_BITFIELD (real_value_class) */ cl : 2;
  44   /* 1 if number is decimal floating point.  */
  45   unsigned int decimal : 1;
  46   /* 1 if number is negative.  */
  47   unsigned int sign : 1;
  48   /* 1 if number is signalling.  */
  49   unsigned int signalling : 1;
  50   /* 1 if number is canonical
  51   All are generally used for handling cases in real.cc.  */
  52   unsigned int canonical : 1;
  53   /* unbiased exponent of the number.  */
  54   unsigned int uexp : EXP_BITS;
  55   /* significand of the number.  */
  56   unsigned long sig[SIGSZ];
  57 };
  58
  59 #define REAL_EXP(REAL) \
  60   ((int)((REAL)->uexp ^ (unsigned int)(1 << (EXP_BITS - 1))) \
  61    - (1 << (EXP_BITS - 1)))
  62 #define SET_REAL_EXP(REAL, EXP) \
  63   ((REAL)->uexp = ((unsigned int)(EXP) & (unsigned int)((1 << EXP_BITS) - 1)))
  64
  65 /* Various headers condition prototypes on #ifdef REAL_VALUE_TYPE, so it
  66    needs to be a macro.  We do need to continue to have a structure tag
  67    so that other headers can forward declare it.  */
  68 #define REAL_VALUE_TYPE struct real_value
  69
  70 /* We store a REAL_VALUE_TYPE into an rtx, and we do this by putting it in
  71    consecutive "w" slots.  Moreover, we've got to compute the number of "w"
  72    slots at preprocessor time, which means we can't use sizeof.  Guess.  */
  73
  74 #define REAL_VALUE_TYPE_SIZE (SIGNIFICAND_BITS + 32)
  75 #define REAL_WIDTH \
  76   (REAL_VALUE_TYPE_SIZE/HOST_BITS_PER_WIDE_INT \
  77    + (REAL_VALUE_TYPE_SIZE%HOST_BITS_PER_WIDE_INT ? 1 : 0)) /* round up */
  78
  79 /* Verify the guess.  */
  80 extern char test_real_width
  81   [sizeof (REAL_VALUE_TYPE) <= REAL_WIDTH * sizeof (HOST_WIDE_INT) ? 1 : -1];
  82
  83 /* Calculate the format for CONST_DOUBLE.  We need as many slots as
  84    are necessary to overlay a REAL_VALUE_TYPE on them.  This could be
  85    as many as four (32-bit HOST_WIDE_INT, 128-bit REAL_VALUE_TYPE).
  86
  87    A number of places assume that there are always at least two 'w'
  88    slots in a CONST_DOUBLE, so we provide them even if one would suffice.  */
  89
  90 #if REAL_WIDTH == 1
  91 # define CONST_DOUBLE_FORMAT     "ww"
  92 #else
  93 # if REAL_WIDTH == 2
  94 #  define CONST_DOUBLE_FORMAT    "ww"
  95 # else
  96 #  if REAL_WIDTH == 3
  97 #   define CONST_DOUBLE_FORMAT   "www"
  98 #  else
  99 #   if REAL_WIDTH == 4
 100 #    define CONST_DOUBLE_FORMAT  "wwww"
 101 #   else
 102 #    if REAL_WIDTH == 5
 103 #     define CONST_DOUBLE_FORMAT "wwwww"
 104 #    else
 105 #     if REAL_WIDTH == 6
 106 #      define CONST_DOUBLE_FORMAT "wwwwww"
 107 #     else
 108        #error "REAL_WIDTH > 6 not supported"
 109 #     endif
 110 #    endif
 111 #   endif
 112 #  endif
 113 # endif
 114 #endif
 115
 116
 117 /* Describes the properties of the specific target format in use.  */
 118 struct real_format
 119 {
 120   /* Move to and from the target bytes.  */
 121   void (*encode) (const struct real_format *, long *,
 122                   const REAL_VALUE_TYPE *);
 123   void (*decode) (const struct real_format *, REAL_VALUE_TYPE *,
 124                   const long *);
 125
 126   /* The radix of the exponent and digits of the significand.  */
 127   int b;
 128
 129   /* Size of the significand in digits of radix B.  */
 130   int p;
 131
 132   /* Size of the significant of a NaN, in digits of radix B.  */
 133   int pnan;
 134
 135   /* The minimum negative integer, x, such that b**(x-1) is normalized.  */
 136   int emin;
 137
 138   /* The maximum integer, x, such that b**(x-1) is representable.  */
 139   int emax;
 140
 141   /* The bit position of the sign bit, for determining whether a value
 142      is positive/negative, or -1 for a complex encoding.  */
 143   int signbit_ro;
 144
 145   /* The bit position of the sign bit, for changing the sign of a number,
 146      or -1 for a complex encoding.  */
 147   int signbit_rw;
 148
 149   /* If this is an IEEE interchange format, the number of bits in the
 150      format; otherwise, if it is an IEEE extended format, one more
 151      than the greatest number of bits in an interchange format it
 152      extends; otherwise 0.  Formats need not follow the IEEE 754-2008
 153      recommended practice regarding how signaling NaNs are identified,
 154      and may vary in the choice of default NaN, but must follow other
 155      IEEE practice regarding having NaNs, infinities and subnormal
 156      values, and the relation of minimum and maximum exponents, and,
 157      for interchange formats, the details of the encoding.  */
 158   int ieee_bits;
 159
 160   /* Default rounding mode for operations on this format.  */
 161   bool round_towards_zero;
 162   bool has_sign_dependent_rounding;
 163
 164   /* Properties of the format.  */
 165   bool has_nans;
 166   bool has_inf;
 167   bool has_denorm;
 168   bool has_signed_zero;
 169   bool qnan_msb_set;
 170   bool canonical_nan_lsbs_set;
 171   const char *name;
 172 };
 173
 174
 175 /* The target format used for each floating point mode.
 176    Float modes are followed by decimal float modes, with entries for
 177    float modes indexed by (MODE - first float mode), and entries for
 178    decimal float modes indexed by (MODE - first decimal float mode) +
 179    the number of float modes.  */
 180 extern const struct real_format *
 181   real_format_for_mode[NUM_MODE_FLOAT + NUM_MODE_DECIMAL_FLOAT];
 182
 183 #define REAL_MODE_FORMAT(MODE)                                          \
 184   (real_format_for_mode[DECIMAL_FLOAT_MODE_P (MODE)                     \
 185                         ? (((MODE) - MIN_MODE_DECIMAL_FLOAT)            \
 186                            + NUM_MODE_FLOAT)                            \
 187                         : GET_MODE_CLASS (MODE) == MODE_FLOAT           \
 188                         ? ((MODE) - MIN_MODE_FLOAT)                     \
 189                         : (gcc_unreachable (), 0)])
 190
 191 #define FLOAT_MODE_FORMAT(MODE) \
 192   (REAL_MODE_FORMAT (as_a <scalar_float_mode> (GET_MODE_INNER (MODE))))
 193
 194 /* The following macro determines whether the floating point format is
 195    composite, i.e. may contain non-consecutive mantissa bits, in which
 196    case compile-time FP overflow may not model run-time overflow.  */
 197 #define MODE_COMPOSITE_P(MODE) \
 198   (FLOAT_MODE_P (MODE) \
 199    && FLOAT_MODE_FORMAT (MODE)->pnan < FLOAT_MODE_FORMAT (MODE)->p)
 200
 201 /* Accessor macros for format properties.  */
 202 #define MODE_HAS_NANS(MODE) \
 203   (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_nans)
 204 #define MODE_HAS_INFINITIES(MODE) \
 205   (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_inf)
 206 #define MODE_HAS_SIGNED_ZEROS(MODE) \
 207   (FLOAT_MODE_P (MODE) && FLOAT_MODE_FORMAT (MODE)->has_signed_zero)
 208 #define MODE_HAS_SIGN_DEPENDENT_ROUNDING(MODE) \
 209   (FLOAT_MODE_P (MODE) \
 210    && FLOAT_MODE_FORMAT (MODE)->has_sign_dependent_rounding)
 211
 212 /* This class allows functions in this file to accept a floating-point
 213    format as either a mode or an explicit real_format pointer.  In the
 214    former case the mode must be VOIDmode (which means "no particular
 215    format") or must satisfy SCALAR_FLOAT_MODE_P.  */
 216 class format_helper
 217 {
 218 public:
 219   format_helper (const real_format *format) : m_format (format) {}
 220   template<typename T> format_helper (const T &);
 221   const real_format *operator-> () const { return m_format; }
 222   operator const real_format *() const { return m_format; }
 223
 224   bool decimal_p () const { return m_format && m_format->b == 10; }
 225   bool can_represent_integral_type_p (tree type) const;
 226
 227 private:
 228   const real_format *m_format;
 229 };
 230
 231 template<typename T>
 232 inline format_helper::format_helper (const T &m)
 233   : m_format (m == VOIDmode ? 0 : REAL_MODE_FORMAT (m))
 234 {}
 235
 236 /* Declare functions in real.cc.  */
 237
 238 /* True if the given mode has a NaN representation and the treatment of
 239    NaN operands is important.  Certain optimizations, such as folding
 240    x * 0 into 0, are not correct for NaN operands, and are normally
 241    disabled for modes with NaNs.  The user can ask for them to be
 242    done anyway using the -funsafe-math-optimizations switch.  */
 243 extern bool HONOR_NANS (machine_mode);
 244 extern bool HONOR_NANS (const_tree);
 245 extern bool HONOR_NANS (const_rtx);
 246
 247 /* Like HONOR_NANs, but true if we honor signaling NaNs (or sNaNs).  */
 248 extern bool HONOR_SNANS (machine_mode);
 249 extern bool HONOR_SNANS (const_tree);
 250 extern bool HONOR_SNANS (const_rtx);
 251
 252 /* As for HONOR_NANS, but true if the mode can represent infinity and
 253    the treatment of infinite values is important.  */
 254 extern bool HONOR_INFINITIES (machine_mode);
 255 extern bool HONOR_INFINITIES (const_tree);
 256 extern bool HONOR_INFINITIES (const_rtx);
 257
 258 /* Like HONOR_NANS, but true if the given mode distinguishes between
 259    positive and negative zero, and the sign of zero is important.  */
 260 extern bool HONOR_SIGNED_ZEROS (machine_mode);
 261 extern bool HONOR_SIGNED_ZEROS (const_tree);
 262 extern bool HONOR_SIGNED_ZEROS (const_rtx);
 263
 264 /* Like HONOR_NANS, but true if given mode supports sign-dependent rounding,
 265    and the rounding mode is important.  */
 266 extern bool HONOR_SIGN_DEPENDENT_ROUNDING (machine_mode);
 267 extern bool HONOR_SIGN_DEPENDENT_ROUNDING (const_tree);
 268 extern bool HONOR_SIGN_DEPENDENT_ROUNDING (const_rtx);
 269
 270 /* Binary or unary arithmetic on tree_code.  */
 271 extern bool real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
 272                              const REAL_VALUE_TYPE *);
 273
 274 /* Compare reals by tree_code.  */
 275 extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 276
 277 /* Determine whether a floating-point value X is infinite.  */
 278 extern bool real_isinf (const REAL_VALUE_TYPE *);
 279
 280 /* Determine whether a floating-point value X is infinite with SIGN.  */
 281 extern bool real_isinf (const REAL_VALUE_TYPE *, bool sign);
 282
 283 /* Determine whether a floating-point value X is a NaN.  */
 284 extern bool real_isnan (const REAL_VALUE_TYPE *);
 285
 286 /* Determine whether a floating-point value X is a signaling NaN.  */
 287 extern bool real_issignaling_nan (const REAL_VALUE_TYPE *);
 288
 289 /* Determine whether floating-point value R is a denormal.  This
 290    function is only valid for normalized values.  */
 291 inline bool
 292 real_isdenormal (const REAL_VALUE_TYPE *r, machine_mode mode)
 293 {
 294   return r->cl == rvc_normal && REAL_EXP (r) < REAL_MODE_FORMAT (mode)->emin;
 295 }
 296
 297 /* Determine whether a floating-point value X is finite.  */
 298 extern bool real_isfinite (const REAL_VALUE_TYPE *);
 299
 300 /* Determine whether a floating-point value X is negative.  */
 301 extern bool real_isneg (const REAL_VALUE_TYPE *);
 302
 303 /* Determine whether a floating-point value X is minus zero.  */
 304 extern bool real_isnegzero (const REAL_VALUE_TYPE *);
 305
 306 /* Determine whether a floating-point value X is plus or minus zero.  */
 307 extern bool real_iszero (const REAL_VALUE_TYPE *);
 308
 309 /* Determine whether a floating-point value X is zero with SIGN.  */
 310 extern bool real_iszero (const REAL_VALUE_TYPE *, bool sign);
 311
 312 /* Test relationships between reals.  */
 313 extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 314 extern bool real_equal (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 315 extern bool real_less (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 316
 317 /* Extend or truncate to a new format.  */
 318 extern void real_convert (REAL_VALUE_TYPE *, format_helper,
 319                           const REAL_VALUE_TYPE *);
 320
 321 /* Return true if truncating to NEW is exact.  */
 322 extern bool exact_real_truncate (format_helper, const REAL_VALUE_TYPE *);
 323
 324 /* Render R as a decimal floating point constant.  */
 325 extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
 326                              size_t, int);
 327
 328 /* Render R as a decimal floating point constant, rounded so as to be
 329    parsed back to the same value when interpreted in mode MODE.  */
 330 extern void real_to_decimal_for_mode (char *, const REAL_VALUE_TYPE *, size_t,
 331                                       size_t, int, machine_mode);
 332
 333 /* Render R as a hexadecimal floating point constant.  */
 334 extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
 335                                  size_t, size_t, int);
 336
 337 /* Render R as an integer.  */
 338 extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
 339
 340 /* Initialize R from a decimal or hexadecimal string.  Return -1 if
 341    the value underflows, +1 if overflows, and 0 otherwise.  */
 342 extern int real_from_string (REAL_VALUE_TYPE *, const char *);
 343 /* Wrapper to allow different internal representation for decimal floats. */
 344 extern void real_from_string3 (REAL_VALUE_TYPE *, const char *, format_helper);
 345
 346 extern long real_to_target (long *, const REAL_VALUE_TYPE *, format_helper);
 347
 348 extern void real_from_target (REAL_VALUE_TYPE *, const long *,
 349                               format_helper);
 350
 351 extern void real_inf (REAL_VALUE_TYPE *, bool sign = false);
 352
 353 extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, format_helper);
 354
 355 extern void real_maxval (REAL_VALUE_TYPE *, int, machine_mode);
 356
 357 extern void real_2expN (REAL_VALUE_TYPE *, int, format_helper);
 358
 359 extern unsigned int real_hash (const REAL_VALUE_TYPE *);
 360
 361
 362 /* Target formats defined in real.cc.  */
 363 extern const struct real_format ieee_single_format;
 364 extern const struct real_format mips_single_format;
 365 extern const struct real_format motorola_single_format;
 366 extern const struct real_format spu_single_format;
 367 extern const struct real_format ieee_double_format;
 368 extern const struct real_format mips_double_format;
 369 extern const struct real_format motorola_double_format;
 370 extern const struct real_format ieee_extended_motorola_format;
 371 extern const struct real_format ieee_extended_intel_96_format;
 372 extern const struct real_format ieee_extended_intel_96_round_53_format;
 373 extern const struct real_format ieee_extended_intel_128_format;
 374 extern const struct real_format ibm_extended_format;
 375 extern const struct real_format mips_extended_format;
 376 extern const struct real_format ieee_quad_format;
 377 extern const struct real_format mips_quad_format;
 378 extern const struct real_format vax_f_format;
 379 extern const struct real_format vax_d_format;
 380 extern const struct real_format vax_g_format;
 381 extern const struct real_format real_internal_format;
 382 extern const struct real_format decimal_single_format;
 383 extern const struct real_format decimal_double_format;
 384 extern const struct real_format decimal_quad_format;
 385 extern const struct real_format ieee_half_format;
 386 extern const struct real_format arm_half_format;
 387 extern const struct real_format arm_bfloat_half_format;
 388
 389
 390 /* ====================================================================== */
 391 /* Crap.  */
 392
 393 /* Determine whether a floating-point value X is infinite.  */
 394 #define REAL_VALUE_ISINF(x)             real_isinf (&(x))
 395
 396 /* Determine whether a floating-point value X is a NaN.  */
 397 #define REAL_VALUE_ISNAN(x)             real_isnan (&(x))
 398
 399 /* Determine whether a floating-point value X is a signaling NaN.  */
 400 #define REAL_VALUE_ISSIGNALING_NAN(x)  real_issignaling_nan (&(x))
 401
 402 /* Determine whether a floating-point value X is negative.  */
 403 #define REAL_VALUE_NEGATIVE(x)          real_isneg (&(x))
 404
 405 /* Determine whether a floating-point value X is minus zero.  */
 406 #define REAL_VALUE_MINUS_ZERO(x)        real_isnegzero (&(x))
 407
 408 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 409 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)                       \
 410   real_to_target (OUT, &(IN),                                           \
 411                   float_mode_for_size (LONG_DOUBLE_TYPE_SIZE).require ())
 412
 413 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
 414   real_to_target (OUT, &(IN), float_mode_for_size (64).require ())
 415
 416 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 417 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
 418   ((OUT) = real_to_target (NULL, &(IN), float_mode_for_size (32).require ()))
 419
 420 /* Real values to IEEE 754 decimal floats.  */
 421
 422 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 423 #define REAL_VALUE_TO_TARGET_DECIMAL128(IN, OUT) \
 424   real_to_target (OUT, &(IN), decimal_float_mode_for_size (128).require ())
 425
 426 #define REAL_VALUE_TO_TARGET_DECIMAL64(IN, OUT) \
 427   real_to_target (OUT, &(IN), decimal_float_mode_for_size (64).require ())
 428
 429 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 430 #define REAL_VALUE_TO_TARGET_DECIMAL32(IN, OUT) \
 431   ((OUT) = real_to_target (NULL, &(IN), \
 432                            decimal_float_mode_for_size (32).require ()))
 433
 434 extern REAL_VALUE_TYPE real_value_truncate (format_helper, REAL_VALUE_TYPE);
 435
 436 extern REAL_VALUE_TYPE real_value_negate (const REAL_VALUE_TYPE *);
 437 extern REAL_VALUE_TYPE real_value_abs (const REAL_VALUE_TYPE *);
 438
 439 extern int significand_size (format_helper);
 440
 441 extern REAL_VALUE_TYPE real_from_string2 (const char *, format_helper);
 442
 443 #define REAL_VALUE_ATOF(s, m) \
 444   real_from_string2 (s, m)
 445
 446 #define CONST_DOUBLE_ATOF(s, m) \
 447   const_double_from_real_value (real_from_string2 (s, m), m)
 448
 449 #define REAL_VALUE_FIX(r) \
 450   real_to_integer (&(r))
 451
 452 /* ??? Not quite right.  */
 453 #define REAL_VALUE_UNSIGNED_FIX(r) \
 454   real_to_integer (&(r))
 455
 456 /* ??? These were added for Paranoia support.  */
 457
 458 /* Return floor log2(R).  */
 459 extern int real_exponent (const REAL_VALUE_TYPE *);
 460
 461 /* R = A * 2**EXP.  */
 462 extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
 463
 464 /* **** End of software floating point emulator interface macros **** */
 465 \f
 466 /* Constant real values 0, 1, 2, -1 and 0.5.  */
 467
 468 extern REAL_VALUE_TYPE dconst0;
 469 extern REAL_VALUE_TYPE dconst1;
 470 extern REAL_VALUE_TYPE dconst2;
 471 extern REAL_VALUE_TYPE dconstm1;
 472 extern REAL_VALUE_TYPE dconsthalf;
 473 extern REAL_VALUE_TYPE dconstinf;
 474 extern REAL_VALUE_TYPE dconstninf;
 475
 476 #define dconst_e() (*dconst_e_ptr ())
 477 #define dconst_third() (*dconst_third_ptr ())
 478 #define dconst_quarter() (*dconst_quarter_ptr ())
 479 #define dconst_sixth() (*dconst_sixth_ptr ())
 480 #define dconst_ninth() (*dconst_ninth_ptr ())
 481 #define dconst_sqrt2() (*dconst_sqrt2_ptr ())
 482
 483 /* Function to return the real value special constant 'e'.  */
 484 extern const REAL_VALUE_TYPE * dconst_e_ptr (void);
 485
 486 /* Returns a cached REAL_VALUE_TYPE corresponding to 1/n, for various n.  */
 487 extern const REAL_VALUE_TYPE *dconst_third_ptr (void);
 488 extern const REAL_VALUE_TYPE *dconst_quarter_ptr (void);
 489 extern const REAL_VALUE_TYPE *dconst_sixth_ptr (void);
 490 extern const REAL_VALUE_TYPE *dconst_ninth_ptr (void);
 491
 492 /* Returns the special REAL_VALUE_TYPE corresponding to sqrt(2).  */
 493 extern const REAL_VALUE_TYPE * dconst_sqrt2_ptr (void);
 494
 495 /* Function to return a real value (not a tree node)
 496    from a given integer constant.  */
 497 REAL_VALUE_TYPE real_value_from_int_cst (const_tree, const_tree);
 498
 499 /* Return a CONST_DOUBLE with value R and mode M.  */
 500 extern rtx const_double_from_real_value (REAL_VALUE_TYPE, machine_mode);
 501
 502 /* Replace R by 1/R in the given format, if the result is exact.  */
 503 extern bool exact_real_inverse (format_helper, REAL_VALUE_TYPE *);
 504
 505 /* Return true if arithmetic on values in IMODE that were promoted
 506    from values in TMODE is equivalent to direct arithmetic on values
 507    in TMODE.  */
 508 bool real_can_shorten_arithmetic (machine_mode, machine_mode);
 509
 510 /* In tree.cc: wrap up a REAL_VALUE_TYPE in a tree node.  */
 511 extern tree build_real (tree, REAL_VALUE_TYPE);
 512
 513 /* Likewise, but first truncate the value to the type.  */
 514 extern tree build_real_truncate (tree, REAL_VALUE_TYPE);
 515
 516 /* Calculate R as X raised to the integer exponent N in format FMT.  */
 517 extern bool real_powi (REAL_VALUE_TYPE *, format_helper,
 518                        const REAL_VALUE_TYPE *, HOST_WIDE_INT);
 519
 520 /* Standard round to integer value functions.  */
 521 extern void real_trunc (REAL_VALUE_TYPE *, format_helper,
 522                         const REAL_VALUE_TYPE *);
 523 extern void real_floor (REAL_VALUE_TYPE *, format_helper,
 524                         const REAL_VALUE_TYPE *);
 525 extern void real_ceil (REAL_VALUE_TYPE *, format_helper,
 526                        const REAL_VALUE_TYPE *);
 527 extern void real_round (REAL_VALUE_TYPE *, format_helper,
 528                         const REAL_VALUE_TYPE *);
 529 extern void real_roundeven (REAL_VALUE_TYPE *, format_helper,
 530                             const REAL_VALUE_TYPE *);
 531
 532 /* Set the sign of R to the sign of X.  */
 533 extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 534
 535 /* Check whether the real constant value given is an integer.  */
 536 extern bool real_isinteger (const REAL_VALUE_TYPE *, format_helper);
 537 extern bool real_isinteger (const REAL_VALUE_TYPE *, HOST_WIDE_INT *);
 538
 539 /* Calculate nextafter (X, Y) in format FMT.  */
 540 extern bool real_nextafter (REAL_VALUE_TYPE *, format_helper,
 541                             const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 542
 543 /* Write into BUF the maximum representable finite floating-point
 544    number, (1 - b**-p) * b**emax for a given FP format FMT as a hex
 545    float string.  BUF must be large enough to contain the result.  */
 546 extern void get_max_float (const struct real_format *, char *, size_t, bool);
 547
 548 #ifndef GENERATOR_FILE
 549 /* real related routines.  */
 550 extern wide_int real_to_integer (const REAL_VALUE_TYPE *, bool *, int);
 551 extern void real_from_integer (REAL_VALUE_TYPE *, format_helper,
 552                                const wide_int_ref &, signop);
 553 #endif
 554
 555 /* Fills r with the largest value such that 1 + r*r won't overflow.
 556    This is used in both sin (atan (x)) and cos (atan(x)) optimizations. */
 557 extern void build_sinatan_real (REAL_VALUE_TYPE *, tree);
 558
 559 #endif /* ! GCC_REAL_H */