gcc/fold-const-call.cc

   1 /* Constant folding for calls to built-in and internal functions.
   2    Copyright (C) 1988-2023 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 #include "config.h"
  21 #include "system.h"
  22 #include "coretypes.h"
  23 #include "realmpfr.h"
  24 #include "tree.h"
  25 #include "stor-layout.h"
  26 #include "options.h"
  27 #include "fold-const.h"
  28 #include "fold-const-call.h"
  29 #include "case-cfn-macros.h"
  30 #include "tm.h" /* For C[LT]Z_DEFINED_AT_ZERO.  */
  31 #include "builtins.h"
  32 #include "gimple-expr.h"
  33 #include "tree-vector-builder.h"
  34
  35 /* Functions that test for certain constant types, abstracting away the
  36    decision about whether to check for overflow.  */
  37
  38 static inline bool
  39 integer_cst_p (tree t)
  40 {
  41   return TREE_CODE (t) == INTEGER_CST && !TREE_OVERFLOW (t);
  42 }
  43
  44 static inline bool
  45 real_cst_p (tree t)
  46 {
  47   return TREE_CODE (t) == REAL_CST && !TREE_OVERFLOW (t);
  48 }
  49
  50 static inline bool
  51 complex_cst_p (tree t)
  52 {
  53   return TREE_CODE (t) == COMPLEX_CST;
  54 }
  55
  56 /* Return true if ARG is a size_type_node constant.
  57    Store it in *SIZE_OUT if so.  */
  58
  59 static inline bool
  60 size_t_cst_p (tree t, unsigned HOST_WIDE_INT *size_out)
  61 {
  62   if (types_compatible_p (size_type_node, TREE_TYPE (t))
  63       && integer_cst_p (t)
  64       && tree_fits_uhwi_p (t))
  65     {
  66       *size_out = tree_to_uhwi (t);
  67       return true;
  68     }
  69   return false;
  70 }
  71
  72 /* RES is the result of a comparison in which < 0 means "less", 0 means
  73    "equal" and > 0 means "more".  Canonicalize it to -1, 0 or 1 and
  74    return it in type TYPE.  */
  75
  76 tree
  77 build_cmp_result (tree type, int res)
  78 {
  79   return build_int_cst (type, res < 0 ? -1 : res > 0 ? 1 : 0);
  80 }
  81
  82 /* M is the result of trying to constant-fold an expression (starting
  83    with clear MPFR flags) and INEXACT says whether the result in M is
  84    exact or inexact.  Return true if M can be used as a constant-folded
  85    result in format FORMAT, storing the value in *RESULT if so.  */
  86
  87 static bool
  88 do_mpfr_ckconv (real_value *result, mpfr_srcptr m, bool inexact,
  89                 const real_format *format)
  90 {
  91   /* Proceed iff we get a normal number, i.e. not NaN or Inf and no
  92      overflow/underflow occurred.  If -frounding-math, proceed iff the
  93      result of calling FUNC was exact.  */
  94   if (!mpfr_number_p (m)
  95       || mpfr_overflow_p ()
  96       || mpfr_underflow_p ()
  97       || (flag_rounding_math && inexact))
  98     return false;
  99
 100   REAL_VALUE_TYPE tmp;
 101   real_from_mpfr (&tmp, m, format, MPFR_RNDN);
 102
 103   /* Proceed iff GCC's REAL_VALUE_TYPE can hold the MPFR values.
 104      If the REAL_VALUE_TYPE is zero but the mpfr_t is not, then we
 105      underflowed in the conversion.  */
 106   if (!real_isfinite (&tmp)
 107       || ((tmp.cl == rvc_zero) != (mpfr_zero_p (m) != 0)))
 108     return false;
 109
 110   real_convert (result, format, &tmp);
 111   return real_identical (result, &tmp);
 112 }
 113
 114 /* Try to evaluate:
 115
 116       *RESULT = f (*ARG)
 117
 118    in format FORMAT, given that FUNC is the MPFR implementation of f.
 119    Return true on success.  */
 120
 121 static bool
 122 do_mpfr_arg1 (real_value *result,
 123               int (*func) (mpfr_ptr, mpfr_srcptr, mpfr_rnd_t),
 124               const real_value *arg, const real_format *format)
 125 {
 126   /* To proceed, MPFR must exactly represent the target floating point
 127      format, which only happens when the target base equals two.  */
 128   if (format->b != 2 || !real_isfinite (arg))
 129     return false;
 130
 131   int prec = format->p;
 132   mpfr_rnd_t rnd = format->round_towards_zero ? MPFR_RNDZ : MPFR_RNDN;
 133
 134   auto_mpfr m (prec);
 135   mpfr_from_real (m, arg, MPFR_RNDN);
 136   mpfr_clear_flags ();
 137   bool inexact = func (m, m, rnd);
 138   bool ok = do_mpfr_ckconv (result, m, inexact, format);
 139
 140   return ok;
 141 }
 142
 143 /* Try to evaluate:
 144
 145       *RESULT_SIN = sin (*ARG);
 146       *RESULT_COS = cos (*ARG);
 147
 148    for format FORMAT.  Return true on success.  */
 149
 150 static bool
 151 do_mpfr_sincos (real_value *result_sin, real_value *result_cos,
 152                 const real_value *arg, const real_format *format)
 153 {
 154   /* To proceed, MPFR must exactly represent the target floating point
 155      format, which only happens when the target base equals two.  */
 156   if (format->b != 2 || !real_isfinite (arg))
 157     return false;
 158
 159   int prec = format->p;
 160   mpfr_rnd_t rnd = format->round_towards_zero ? MPFR_RNDZ : MPFR_RNDN;
 161   mpfr_t m, ms, mc;
 162
 163   mpfr_inits2 (prec, m, ms, mc, NULL);
 164   mpfr_from_real (m, arg, MPFR_RNDN);
 165   mpfr_clear_flags ();
 166   bool inexact = mpfr_sin_cos (ms, mc, m, rnd);
 167   bool ok = (do_mpfr_ckconv (result_sin, ms, inexact, format)
 168              && do_mpfr_ckconv (result_cos, mc, inexact, format));
 169   mpfr_clears (m, ms, mc, NULL);
 170
 171   return ok;
 172 }
 173
 174 /* Try to evaluate:
 175
 176       *RESULT = f (*ARG0, *ARG1)
 177
 178    in format FORMAT, given that FUNC is the MPFR implementation of f.
 179    Return true on success.  */
 180
 181 static bool
 182 do_mpfr_arg2 (real_value *result,
 183               int (*func) (mpfr_ptr, mpfr_srcptr, mpfr_srcptr, mpfr_rnd_t),
 184               const real_value *arg0, const real_value *arg1,
 185               const real_format *format)
 186 {
 187   /* To proceed, MPFR must exactly represent the target floating point
 188      format, which only happens when the target base equals two.  */
 189   if (format->b != 2 || !real_isfinite (arg0) || !real_isfinite (arg1))
 190     return false;
 191
 192   int prec = format->p;
 193   mpfr_rnd_t rnd = format->round_towards_zero ? MPFR_RNDZ : MPFR_RNDN;
 194   mpfr_t m0, m1;
 195
 196   mpfr_inits2 (prec, m0, m1, NULL);
 197   mpfr_from_real (m0, arg0, MPFR_RNDN);
 198   mpfr_from_real (m1, arg1, MPFR_RNDN);
 199   mpfr_clear_flags ();
 200   bool inexact = func (m0, m0, m1, rnd);
 201   bool ok = do_mpfr_ckconv (result, m0, inexact, format);
 202   mpfr_clears (m0, m1, NULL);
 203
 204   return ok;
 205 }
 206
 207 /* Try to evaluate:
 208
 209       *RESULT = f (ARG0, *ARG1)
 210
 211    in format FORMAT, given that FUNC is the MPFR implementation of f.
 212    Return true on success.  */
 213
 214 static bool
 215 do_mpfr_arg2 (real_value *result,
 216               int (*func) (mpfr_ptr, long, mpfr_srcptr, mpfr_rnd_t),
 217               const wide_int_ref &arg0, const real_value *arg1,
 218               const real_format *format)
 219 {
 220   if (format->b != 2 || !real_isfinite (arg1))
 221     return false;
 222
 223   int prec = format->p;
 224   mpfr_rnd_t rnd = format->round_towards_zero ? MPFR_RNDZ : MPFR_RNDN;
 225
 226   auto_mpfr m (prec);
 227   mpfr_from_real (m, arg1, MPFR_RNDN);
 228   mpfr_clear_flags ();
 229   bool inexact = func (m, arg0.to_shwi (), m, rnd);
 230   bool ok = do_mpfr_ckconv (result, m, inexact, format);
 231
 232   return ok;
 233 }
 234
 235 /* Try to evaluate:
 236
 237       *RESULT = f (*ARG0, *ARG1, *ARG2)
 238
 239    in format FORMAT, given that FUNC is the MPFR implementation of f.
 240    Return true on success.  */
 241
 242 static bool
 243 do_mpfr_arg3 (real_value *result,
 244               int (*func) (mpfr_ptr, mpfr_srcptr, mpfr_srcptr,
 245                            mpfr_srcptr, mpfr_rnd_t),
 246               const real_value *arg0, const real_value *arg1,
 247               const real_value *arg2, const real_format *format)
 248 {
 249   /* To proceed, MPFR must exactly represent the target floating point
 250      format, which only happens when the target base equals two.  */
 251   if (format->b != 2
 252       || !real_isfinite (arg0)
 253       || !real_isfinite (arg1)
 254       || !real_isfinite (arg2))
 255     return false;
 256
 257   int prec = format->p;
 258   mpfr_rnd_t rnd = format->round_towards_zero ? MPFR_RNDZ : MPFR_RNDN;
 259   mpfr_t m0, m1, m2;
 260
 261   mpfr_inits2 (prec, m0, m1, m2, NULL);
 262   mpfr_from_real (m0, arg0, MPFR_RNDN);
 263   mpfr_from_real (m1, arg1, MPFR_RNDN);
 264   mpfr_from_real (m2, arg2, MPFR_RNDN);
 265   mpfr_clear_flags ();
 266   bool inexact = func (m0, m0, m1, m2, rnd);
 267   bool ok = do_mpfr_ckconv (result, m0, inexact, format);
 268   mpfr_clears (m0, m1, m2, NULL);
 269
 270   return ok;
 271 }
 272
 273 /* M is the result of trying to constant-fold an expression (starting
 274    with clear MPFR flags) and INEXACT says whether the result in M is
 275    exact or inexact.  Return true if M can be used as a constant-folded
 276    result in which the real and imaginary parts have format FORMAT.
 277    Store those parts in *RESULT_REAL and *RESULT_IMAG if so.  */
 278
 279 static bool
 280 do_mpc_ckconv (real_value *result_real, real_value *result_imag,
 281                mpc_srcptr m, bool inexact, const real_format *format)
 282 {
 283   /* Proceed iff we get a normal number, i.e. not NaN or Inf and no
 284      overflow/underflow occurred.  If -frounding-math, proceed iff the
 285      result of calling FUNC was exact.  */
 286   if (!mpfr_number_p (mpc_realref (m))
 287       || !mpfr_number_p (mpc_imagref (m))
 288       || mpfr_overflow_p ()
 289       || mpfr_underflow_p ()
 290       || (flag_rounding_math && inexact))
 291     return false;
 292
 293   REAL_VALUE_TYPE tmp_real, tmp_imag;
 294   real_from_mpfr (&tmp_real, mpc_realref (m), format, MPFR_RNDN);
 295   real_from_mpfr (&tmp_imag, mpc_imagref (m), format, MPFR_RNDN);
 296
 297   /* Proceed iff GCC's REAL_VALUE_TYPE can hold the MPFR values.
 298      If the REAL_VALUE_TYPE is zero but the mpfr_t is not, then we
 299      underflowed in the conversion.  */
 300   if (!real_isfinite (&tmp_real)
 301       || !real_isfinite (&tmp_imag)
 302       || (tmp_real.cl == rvc_zero) != (mpfr_zero_p (mpc_realref (m)) != 0)
 303       || (tmp_imag.cl == rvc_zero) != (mpfr_zero_p (mpc_imagref (m)) != 0))
 304     return false;
 305
 306   real_convert (result_real, format, &tmp_real);
 307   real_convert (result_imag, format, &tmp_imag);
 308
 309   return (real_identical (result_real, &tmp_real)
 310           && real_identical (result_imag, &tmp_imag));
 311 }
 312
 313 /* Try to evaluate:
 314
 315       RESULT = f (ARG)
 316
 317    in format FORMAT, given that FUNC is the mpc implementation of f.
 318    Return true on success.  Both RESULT and ARG are represented as
 319    real and imaginary pairs.  */
 320
 321 static bool
 322 do_mpc_arg1 (real_value *result_real, real_value *result_imag,
 323              int (*func) (mpc_ptr, mpc_srcptr, mpc_rnd_t),
 324              const real_value *arg_real, const real_value *arg_imag,
 325              const real_format *format)
 326 {
 327   /* To proceed, MPFR must exactly represent the target floating point
 328      format, which only happens when the target base equals two.  */
 329   if (format->b != 2
 330       || !real_isfinite (arg_real)
 331       || !real_isfinite (arg_imag))
 332     return false;
 333
 334   int prec = format->p;
 335   mpc_rnd_t crnd = format->round_towards_zero ? MPC_RNDZZ : MPC_RNDNN;
 336   mpc_t m;
 337
 338   mpc_init2 (m, prec);
 339   mpfr_from_real (mpc_realref (m), arg_real, MPFR_RNDN);
 340   mpfr_from_real (mpc_imagref (m), arg_imag, MPFR_RNDN);
 341   mpfr_clear_flags ();
 342   bool inexact = func (m, m, crnd);
 343   bool ok = do_mpc_ckconv (result_real, result_imag, m, inexact, format);
 344   mpc_clear (m);
 345
 346   return ok;
 347 }
 348
 349 /* Try to evaluate:
 350
 351       RESULT = f (ARG0, ARG1)
 352
 353    in format FORMAT, given that FUNC is the mpc implementation of f.
 354    Return true on success.  RESULT, ARG0 and ARG1 are represented as
 355    real and imaginary pairs.  */
 356
 357 static bool
 358 do_mpc_arg2 (real_value *result_real, real_value *result_imag,
 359              int (*func)(mpc_ptr, mpc_srcptr, mpc_srcptr, mpc_rnd_t),
 360              const real_value *arg0_real, const real_value *arg0_imag,
 361              const real_value *arg1_real, const real_value *arg1_imag,
 362              const real_format *format)
 363 {
 364   if (!real_isfinite (arg0_real)
 365       || !real_isfinite (arg0_imag)
 366       || !real_isfinite (arg1_real)
 367       || !real_isfinite (arg1_imag))
 368     return false;
 369
 370   int prec = format->p;
 371   mpc_rnd_t crnd = format->round_towards_zero ? MPC_RNDZZ : MPC_RNDNN;
 372   mpc_t m0, m1;
 373
 374   mpc_init2 (m0, prec);
 375   mpc_init2 (m1, prec);
 376   mpfr_from_real (mpc_realref (m0), arg0_real, MPFR_RNDN);
 377   mpfr_from_real (mpc_imagref (m0), arg0_imag, MPFR_RNDN);
 378   mpfr_from_real (mpc_realref (m1), arg1_real, MPFR_RNDN);
 379   mpfr_from_real (mpc_imagref (m1), arg1_imag, MPFR_RNDN);
 380   mpfr_clear_flags ();
 381   bool inexact = func (m0, m0, m1, crnd);
 382   bool ok = do_mpc_ckconv (result_real, result_imag, m0, inexact, format);
 383   mpc_clear (m0);
 384   mpc_clear (m1);
 385
 386   return ok;
 387 }
 388
 389 /* Try to evaluate:
 390
 391       *RESULT = logb (*ARG)
 392
 393    in format FORMAT.  Return true on success.  */
 394
 395 static bool
 396 fold_const_logb (real_value *result, const real_value *arg,
 397                  const real_format *format)
 398 {
 399   switch (arg->cl)
 400     {
 401     case rvc_nan:
 402       /* If arg is +-NaN, then return it.  */
 403       *result = *arg;
 404       return true;
 405
 406     case rvc_inf:
 407       /* If arg is +-Inf, then return +Inf.  */
 408       *result = *arg;
 409       result->sign = 0;
 410       return true;
 411
 412     case rvc_zero:
 413       /* Zero may set errno and/or raise an exception.  */
 414       return false;
 415
 416     case rvc_normal:
 417       /* For normal numbers, proceed iff radix == 2.  In GCC,
 418          normalized significands are in the range [0.5, 1.0).  We
 419          want the exponent as if they were [1.0, 2.0) so get the
 420          exponent and subtract 1.  */
 421       if (format->b == 2)
 422         {
 423           real_from_integer (result, format, REAL_EXP (arg) - 1, SIGNED);
 424           return true;
 425         }
 426       return false;
 427     }
 428 }
 429
 430 /* Try to evaluate:
 431
 432       *RESULT = significand (*ARG)
 433
 434    in format FORMAT.  Return true on success.  */
 435
 436 static bool
 437 fold_const_significand (real_value *result, const real_value *arg,
 438                         const real_format *format)
 439 {
 440   switch (arg->cl)
 441     {
 442     case rvc_zero:
 443     case rvc_nan:
 444     case rvc_inf:
 445       /* If arg is +-0, +-Inf or +-NaN, then return it.  */
 446       *result = *arg;
 447       return true;
 448
 449     case rvc_normal:
 450       /* For normal numbers, proceed iff radix == 2.  */
 451       if (format->b == 2)
 452         {
 453           *result = *arg;
 454           /* In GCC, normalized significands are in the range [0.5, 1.0).
 455              We want them to be [1.0, 2.0) so set the exponent to 1.  */
 456           SET_REAL_EXP (result, 1);
 457           return true;
 458         }
 459       return false;
 460     }
 461 }
 462
 463 /* Try to evaluate:
 464
 465       *RESULT = f (*ARG)
 466
 467    where FORMAT is the format of *ARG and PRECISION is the number of
 468    significant bits in the result.  Return true on success.  */
 469
 470 static bool
 471 fold_const_conversion (wide_int *result,
 472                        void (*fn) (real_value *, format_helper,
 473                                    const real_value *),
 474                        const real_value *arg, unsigned int precision,
 475                        const real_format *format)
 476 {
 477   if (!real_isfinite (arg))
 478     return false;
 479
 480   real_value rounded;
 481   fn (&rounded, format, arg);
 482
 483   bool fail = false;
 484   *result = real_to_integer (&rounded, &fail, precision);
 485   return !fail;
 486 }
 487
 488 /* Try to evaluate:
 489
 490       *RESULT = pow (*ARG0, *ARG1)
 491
 492    in format FORMAT.  Return true on success.  */
 493
 494 static bool
 495 fold_const_pow (real_value *result, const real_value *arg0,
 496                 const real_value *arg1, const real_format *format)
 497 {
 498   if (do_mpfr_arg2 (result, mpfr_pow, arg0, arg1, format))
 499     return true;
 500
 501   /* Check for an integer exponent.  */
 502   REAL_VALUE_TYPE cint1;
 503   HOST_WIDE_INT n1 = real_to_integer (arg1);
 504   real_from_integer (&cint1, VOIDmode, n1, SIGNED);
 505   /* Attempt to evaluate pow at compile-time, unless this should
 506      raise an exception.  */
 507   if (real_identical (arg1, &cint1)
 508       && (n1 > 0
 509           || (!flag_trapping_math && !flag_errno_math)
 510           || !real_equal (arg0, &dconst0)))
 511     {
 512       bool inexact = real_powi (result, format, arg0, n1);
 513       /* Avoid the folding if flag_signaling_nans is on.  */
 514       if (flag_unsafe_math_optimizations
 515           || (!inexact
 516               && !(flag_signaling_nans
 517                    && REAL_VALUE_ISSIGNALING_NAN (*arg0))))
 518         return true;
 519     }
 520
 521   return false;
 522 }
 523
 524 /* Try to evaluate:
 525
 526       *RESULT = nextafter (*ARG0, *ARG1)
 527
 528    or
 529
 530       *RESULT = nexttoward (*ARG0, *ARG1)
 531
 532    in format FORMAT.  Return true on success.  */
 533
 534 static bool
 535 fold_const_nextafter (real_value *result, const real_value *arg0,
 536                       const real_value *arg1, const real_format *format)
 537 {
 538   if (REAL_VALUE_ISSIGNALING_NAN (*arg0)
 539       || REAL_VALUE_ISSIGNALING_NAN (*arg1))
 540     return false;
 541
 542   /* Don't handle composite modes, nor decimal, nor modes without
 543      inf or denorm at least for now.  */
 544   if (format->pnan < format->p
 545       || format->b == 10
 546       || !format->has_inf
 547       || !format->has_denorm)
 548     return false;
 549
 550   if (real_nextafter (result, format, arg0, arg1)
 551       /* If raising underflow or overflow and setting errno to ERANGE,
 552          fail if we care about those side-effects.  */
 553       && (flag_trapping_math || flag_errno_math))
 554     return false;
 555   /* Similarly for nextafter (0, 1) raising underflow.  */
 556   else if (flag_trapping_math
 557            && arg0->cl == rvc_zero
 558            && result->cl != rvc_zero)
 559     return false;
 560
 561   real_convert (result, format, result);
 562
 563   return true;
 564 }
 565
 566 /* Try to evaluate:
 567
 568       *RESULT = ldexp (*ARG0, ARG1)
 569
 570    in format FORMAT.  Return true on success.  */
 571
 572 static bool
 573 fold_const_builtin_load_exponent (real_value *result, const real_value *arg0,
 574                                   const wide_int_ref &arg1,
 575                                   const real_format *format)
 576 {
 577   /* Bound the maximum adjustment to twice the range of the
 578      mode's valid exponents.  Use abs to ensure the range is
 579      positive as a sanity check.  */
 580   int max_exp_adj = 2 * labs (format->emax - format->emin);
 581
 582   /* The requested adjustment must be inside this range.  This
 583      is a preliminary cap to avoid things like overflow, we
 584      may still fail to compute the result for other reasons.  */
 585   if (wi::les_p (arg1, -max_exp_adj) || wi::ges_p (arg1, max_exp_adj))
 586     return false;
 587
 588   /* Don't perform operation if we honor signaling NaNs and
 589      operand is a signaling NaN.  */
 590   if (!flag_unsafe_math_optimizations
 591       && flag_signaling_nans
 592       && REAL_VALUE_ISSIGNALING_NAN (*arg0))
 593     return false;
 594
 595   REAL_VALUE_TYPE initial_result;
 596   real_ldexp (&initial_result, arg0, arg1.to_shwi ());
 597
 598   /* Ensure we didn't overflow.  */
 599   if (real_isinf (&initial_result))
 600     return false;
 601
 602   /* Only proceed if the target mode can hold the
 603      resulting value.  */
 604   *result = real_value_truncate (format, initial_result);
 605   return real_equal (&initial_result, result);
 606 }
 607
 608 /* Fold a call to __builtin_nan or __builtin_nans with argument ARG and
 609    return type TYPE.  QUIET is true if a quiet rather than signalling
 610    NaN is required.  */
 611
 612 static tree
 613 fold_const_builtin_nan (tree type, tree arg, bool quiet)
 614 {
 615   REAL_VALUE_TYPE real;
 616   const char *str = c_getstr (arg);
 617   if (str && real_nan (&real, str, quiet, TYPE_MODE (type)))
 618     return build_real (type, real);
 619   return NULL_TREE;
 620 }
 621
 622 /* Fold a call to IFN_REDUC_<CODE> (ARG), returning a value of type TYPE.  */
 623
 624 static tree
 625 fold_const_reduction (tree type, tree arg, tree_code code)
 626 {
 627   unsigned HOST_WIDE_INT nelts;
 628   if (TREE_CODE (arg) != VECTOR_CST
 629       || !VECTOR_CST_NELTS (arg).is_constant (&nelts))
 630     return NULL_TREE;
 631
 632   tree res = VECTOR_CST_ELT (arg, 0);
 633   for (unsigned HOST_WIDE_INT i = 1; i < nelts; i++)
 634     {
 635       res = const_binop (code, type, res, VECTOR_CST_ELT (arg, i));
 636       if (res == NULL_TREE || !CONSTANT_CLASS_P (res))
 637         return NULL_TREE;
 638     }
 639   return res;
 640 }
 641
 642 /* Fold a call to IFN_VEC_CONVERT (ARG) returning TYPE.  */
 643
 644 static tree
 645 fold_const_vec_convert (tree ret_type, tree arg)
 646 {
 647   enum tree_code code = NOP_EXPR;
 648   tree arg_type = TREE_TYPE (arg);
 649   if (TREE_CODE (arg) != VECTOR_CST)
 650     return NULL_TREE;
 651
 652   gcc_checking_assert (VECTOR_TYPE_P (ret_type) && VECTOR_TYPE_P (arg_type));
 653
 654   if (INTEGRAL_TYPE_P (TREE_TYPE (ret_type))
 655       && SCALAR_FLOAT_TYPE_P (TREE_TYPE (arg_type)))
 656     code = FIX_TRUNC_EXPR;
 657   else if (INTEGRAL_TYPE_P (TREE_TYPE (arg_type))
 658            && SCALAR_FLOAT_TYPE_P (TREE_TYPE (ret_type)))
 659     code = FLOAT_EXPR;
 660
 661   /* We can't handle steps directly when extending, since the
 662      values need to wrap at the original precision first.  */
 663   bool step_ok_p
 664     = (INTEGRAL_TYPE_P (TREE_TYPE (ret_type))
 665        && INTEGRAL_TYPE_P (TREE_TYPE (arg_type))
 666        && (TYPE_PRECISION (TREE_TYPE (ret_type))
 667            <= TYPE_PRECISION (TREE_TYPE (arg_type))));
 668   tree_vector_builder elts;
 669   if (!elts.new_unary_operation (ret_type, arg, step_ok_p))
 670     return NULL_TREE;
 671
 672   unsigned int count = elts.encoded_nelts ();
 673   for (unsigned int i = 0; i < count; ++i)
 674     {
 675       tree elt = fold_unary (code, TREE_TYPE (ret_type),
 676                              VECTOR_CST_ELT (arg, i));
 677       if (elt == NULL_TREE || !CONSTANT_CLASS_P (elt))
 678         return NULL_TREE;
 679       elts.quick_push (elt);
 680     }
 681
 682   return elts.build ();
 683 }
 684
 685 /* Try to evaluate:
 686
 687       IFN_WHILE_ULT (ARG0, ARG1, (TYPE) { ... })
 688
 689    Return the value on success and null on failure.  */
 690
 691 static tree
 692 fold_while_ult (tree type, poly_uint64 arg0, poly_uint64 arg1)
 693 {
 694   if (known_ge (arg0, arg1))
 695     return build_zero_cst (type);
 696
 697   if (maybe_ge (arg0, arg1))
 698     return NULL_TREE;
 699
 700   poly_uint64 diff = arg1 - arg0;
 701   poly_uint64 nelts = TYPE_VECTOR_SUBPARTS (type);
 702   if (known_ge (diff, nelts))
 703     return build_all_ones_cst (type);
 704
 705   unsigned HOST_WIDE_INT const_diff;
 706   if (known_le (diff, nelts) && diff.is_constant (&const_diff))
 707     {
 708       tree minus_one = build_minus_one_cst (TREE_TYPE (type));
 709       tree zero = build_zero_cst (TREE_TYPE (type));
 710       return build_vector_a_then_b (type, const_diff, minus_one, zero);
 711     }
 712   return NULL_TREE;
 713 }
 714
 715 /* Try to evaluate:
 716
 717       *RESULT = FN (*ARG)
 718
 719    in format FORMAT.  Return true on success.  */
 720
 721 static bool
 722 fold_const_call_ss (real_value *result, combined_fn fn,
 723                     const real_value *arg, const real_format *format)
 724 {
 725   switch (fn)
 726     {
 727     CASE_CFN_SQRT:
 728     CASE_CFN_SQRT_FN:
 729       return (real_compare (GE_EXPR, arg, &dconst0)
 730               && do_mpfr_arg1 (result, mpfr_sqrt, arg, format));
 731
 732     CASE_CFN_CBRT:
 733     CASE_CFN_CBRT_FN:
 734       return do_mpfr_arg1 (result, mpfr_cbrt, arg, format);
 735
 736     CASE_CFN_ASIN:
 737     CASE_CFN_ASIN_FN:
 738       return (real_compare (GE_EXPR, arg, &dconstm1)
 739               && real_compare (LE_EXPR, arg, &dconst1)
 740               && do_mpfr_arg1 (result, mpfr_asin, arg, format));
 741
 742     CASE_CFN_ACOS:
 743     CASE_CFN_ACOS_FN:
 744       return (real_compare (GE_EXPR, arg, &dconstm1)
 745               && real_compare (LE_EXPR, arg, &dconst1)
 746               && do_mpfr_arg1 (result, mpfr_acos, arg, format));
 747
 748     CASE_CFN_ATAN:
 749     CASE_CFN_ATAN_FN:
 750       return do_mpfr_arg1 (result, mpfr_atan, arg, format);
 751
 752     CASE_CFN_ASINH:
 753     CASE_CFN_ASINH_FN:
 754       return do_mpfr_arg1 (result, mpfr_asinh, arg, format);
 755
 756     CASE_CFN_ACOSH:
 757     CASE_CFN_ACOSH_FN:
 758       return (real_compare (GE_EXPR, arg, &dconst1)
 759               && do_mpfr_arg1 (result, mpfr_acosh, arg, format));
 760
 761     CASE_CFN_ATANH:
 762     CASE_CFN_ATANH_FN:
 763       return (real_compare (GE_EXPR, arg, &dconstm1)
 764               && real_compare (LE_EXPR, arg, &dconst1)
 765               && do_mpfr_arg1 (result, mpfr_atanh, arg, format));
 766
 767     CASE_CFN_SIN:
 768     CASE_CFN_SIN_FN:
 769       return do_mpfr_arg1 (result, mpfr_sin, arg, format);
 770
 771     CASE_CFN_COS:
 772     CASE_CFN_COS_FN:
 773       return do_mpfr_arg1 (result, mpfr_cos, arg, format);
 774
 775     CASE_CFN_TAN:
 776     CASE_CFN_TAN_FN:
 777       return do_mpfr_arg1 (result, mpfr_tan, arg, format);
 778
 779     CASE_CFN_SINH:
 780     CASE_CFN_SINH_FN:
 781       return do_mpfr_arg1 (result, mpfr_sinh, arg, format);
 782
 783     CASE_CFN_COSH:
 784     CASE_CFN_COSH_FN:
 785       return do_mpfr_arg1 (result, mpfr_cosh, arg, format);
 786
 787     CASE_CFN_TANH:
 788     CASE_CFN_TANH_FN:
 789       return do_mpfr_arg1 (result, mpfr_tanh, arg, format);
 790
 791     CASE_CFN_ERF:
 792     CASE_CFN_ERF_FN:
 793       return do_mpfr_arg1 (result, mpfr_erf, arg, format);
 794
 795     CASE_CFN_ERFC:
 796     CASE_CFN_ERFC_FN:
 797       return do_mpfr_arg1 (result, mpfr_erfc, arg, format);
 798
 799     CASE_CFN_TGAMMA:
 800     CASE_CFN_TGAMMA_FN:
 801       return do_mpfr_arg1 (result, mpfr_gamma, arg, format);
 802
 803     CASE_CFN_EXP:
 804     CASE_CFN_EXP_FN:
 805       return do_mpfr_arg1 (result, mpfr_exp, arg, format);
 806
 807     CASE_CFN_EXP2:
 808     CASE_CFN_EXP2_FN:
 809       return do_mpfr_arg1 (result, mpfr_exp2, arg, format);
 810
 811     CASE_CFN_EXP10:
 812     CASE_CFN_POW10:
 813       return do_mpfr_arg1 (result, mpfr_exp10, arg, format);
 814
 815     CASE_CFN_EXPM1:
 816     CASE_CFN_EXPM1_FN:
 817       return do_mpfr_arg1 (result, mpfr_expm1, arg, format);
 818
 819     CASE_CFN_LOG:
 820     CASE_CFN_LOG_FN:
 821       return (real_compare (GT_EXPR, arg, &dconst0)
 822               && do_mpfr_arg1 (result, mpfr_log, arg, format));
 823
 824     CASE_CFN_LOG2:
 825     CASE_CFN_LOG2_FN:
 826       return (real_compare (GT_EXPR, arg, &dconst0)
 827               && do_mpfr_arg1 (result, mpfr_log2, arg, format));
 828
 829     CASE_CFN_LOG10:
 830     CASE_CFN_LOG10_FN:
 831       return (real_compare (GT_EXPR, arg, &dconst0)
 832               && do_mpfr_arg1 (result, mpfr_log10, arg, format));
 833
 834     CASE_CFN_LOG1P:
 835     CASE_CFN_LOG1P_FN:
 836       return (real_compare (GT_EXPR, arg, &dconstm1)
 837               && do_mpfr_arg1 (result, mpfr_log1p, arg, format));
 838
 839     CASE_CFN_J0:
 840       return do_mpfr_arg1 (result, mpfr_j0, arg, format);
 841
 842     CASE_CFN_J1:
 843       return do_mpfr_arg1 (result, mpfr_j1, arg, format);
 844
 845     CASE_CFN_Y0:
 846       return (real_compare (GT_EXPR, arg, &dconst0)
 847               && do_mpfr_arg1 (result, mpfr_y0, arg, format));
 848
 849     CASE_CFN_Y1:
 850       return (real_compare (GT_EXPR, arg, &dconst0)
 851               && do_mpfr_arg1 (result, mpfr_y1, arg, format));
 852
 853     CASE_CFN_FLOOR:
 854     CASE_CFN_FLOOR_FN:
 855       if (!REAL_VALUE_ISSIGNALING_NAN (*arg))
 856         {
 857           real_floor (result, format, arg);
 858           return true;
 859         }
 860       return false;
 861
 862     CASE_CFN_CEIL:
 863     CASE_CFN_CEIL_FN:
 864       if (!REAL_VALUE_ISSIGNALING_NAN (*arg))
 865         {
 866           real_ceil (result, format, arg);
 867           return true;
 868         }
 869       return false;
 870
 871     CASE_CFN_TRUNC:
 872     CASE_CFN_TRUNC_FN:
 873       if (!REAL_VALUE_ISSIGNALING_NAN (*arg))
 874         {
 875           real_trunc (result, format, arg);
 876           return true;
 877         }
 878       return false;
 879
 880     CASE_CFN_ROUND:
 881     CASE_CFN_ROUND_FN:
 882       if (!REAL_VALUE_ISSIGNALING_NAN (*arg))
 883         {
 884           real_round (result, format, arg);
 885           return true;
 886         }
 887       return false;
 888
 889     CASE_CFN_ROUNDEVEN:
 890     CASE_CFN_ROUNDEVEN_FN:
 891       if (!REAL_VALUE_ISSIGNALING_NAN (*arg))
 892         {
 893           real_roundeven (result, format, arg);
 894           return true;
 895         }
 896       return false;
 897
 898     CASE_CFN_LOGB:
 899     CASE_CFN_LOGB_FN:
 900       return fold_const_logb (result, arg, format);
 901
 902     CASE_CFN_SIGNIFICAND:
 903       return fold_const_significand (result, arg, format);
 904
 905     default:
 906       return false;
 907     }
 908 }
 909
 910 /* Try to evaluate:
 911
 912       *RESULT = FN (*ARG)
 913
 914    where FORMAT is the format of ARG and PRECISION is the number of
 915    significant bits in the result.  Return true on success.  */
 916
 917 static bool
 918 fold_const_call_ss (wide_int *result, combined_fn fn,
 919                     const real_value *arg, unsigned int precision,
 920                     const real_format *format)
 921 {
 922   switch (fn)
 923     {
 924     CASE_CFN_SIGNBIT:
 925       if (real_isneg (arg))
 926         *result = wi::one (precision);
 927       else
 928         *result = wi::zero (precision);
 929       return true;
 930
 931     CASE_CFN_ILOGB:
 932     CASE_CFN_ILOGB_FN:
 933       /* For ilogb we don't know FP_ILOGB0, so only handle normal values.
 934          Proceed iff radix == 2.  In GCC, normalized significands are in
 935          the range [0.5, 1.0).  We want the exponent as if they were
 936          [1.0, 2.0) so get the exponent and subtract 1.  */
 937       if (arg->cl == rvc_normal && format->b == 2)
 938         {
 939           *result = wi::shwi (REAL_EXP (arg) - 1, precision);
 940           return true;
 941         }
 942       return false;
 943
 944     CASE_CFN_ICEIL:
 945     CASE_CFN_LCEIL:
 946     CASE_CFN_LLCEIL:
 947       return fold_const_conversion (result, real_ceil, arg,
 948                                     precision, format);
 949
 950     CASE_CFN_LFLOOR:
 951     CASE_CFN_IFLOOR:
 952     CASE_CFN_LLFLOOR:
 953       return fold_const_conversion (result, real_floor, arg,
 954                                     precision, format);
 955
 956     CASE_CFN_IROUND:
 957     CASE_CFN_LROUND:
 958     CASE_CFN_LROUND_FN:
 959     CASE_CFN_LLROUND:
 960     CASE_CFN_LLROUND_FN:
 961       return fold_const_conversion (result, real_round, arg,
 962                                     precision, format);
 963
 964     CASE_CFN_IRINT:
 965     CASE_CFN_LRINT:
 966     CASE_CFN_LRINT_FN:
 967     CASE_CFN_LLRINT:
 968     CASE_CFN_LLRINT_FN:
 969       /* Not yet folded to a constant.  */
 970       return false;
 971
 972     CASE_CFN_FINITE:
 973     case CFN_BUILT_IN_FINITED32:
 974     case CFN_BUILT_IN_FINITED64:
 975     case CFN_BUILT_IN_FINITED128:
 976     case CFN_BUILT_IN_ISFINITE:
 977       *result = wi::shwi (real_isfinite (arg) ? 1 : 0, precision);
 978       return true;
 979
 980     case CFN_BUILT_IN_ISSIGNALING:
 981       *result = wi::shwi (real_issignaling_nan (arg) ? 1 : 0, precision);
 982       return true;
 983
 984     CASE_CFN_ISINF:
 985     case CFN_BUILT_IN_ISINFD32:
 986     case CFN_BUILT_IN_ISINFD64:
 987     case CFN_BUILT_IN_ISINFD128:
 988       if (real_isinf (arg))
 989         *result = wi::shwi (arg->sign ? -1 : 1, precision);
 990       else
 991         *result = wi::shwi (0, precision);
 992       return true;
 993
 994     CASE_CFN_ISNAN:
 995     case CFN_BUILT_IN_ISNAND32:
 996     case CFN_BUILT_IN_ISNAND64:
 997     case CFN_BUILT_IN_ISNAND128:
 998       *result = wi::shwi (real_isnan (arg) ? 1 : 0, precision);
 999       return true;
1000
1001     default:
1002       return false;
1003     }
1004 }
1005
1006 /* Try to evaluate:
1007
1008       *RESULT = FN (ARG)
1009
1010    where ARG_TYPE is the type of ARG and PRECISION is the number of bits
1011    in the result.  Return true on success.  */
1012
1013 static bool
1014 fold_const_call_ss (wide_int *result, combined_fn fn, const wide_int_ref &arg,
1015                     unsigned int precision, tree arg_type)
1016 {
1017   switch (fn)
1018     {
1019     CASE_CFN_FFS:
1020       *result = wi::shwi (wi::ffs (arg), precision);
1021       return true;
1022
1023     CASE_CFN_CLZ:
1024       {
1025         int tmp;
1026         if (wi::ne_p (arg, 0))
1027           tmp = wi::clz (arg);
1028         else if (!CLZ_DEFINED_VALUE_AT_ZERO (SCALAR_INT_TYPE_MODE (arg_type),
1029                                              tmp))
1030           tmp = TYPE_PRECISION (arg_type);
1031         *result = wi::shwi (tmp, precision);
1032         return true;
1033       }
1034
1035     CASE_CFN_CTZ:
1036       {
1037         int tmp;
1038         if (wi::ne_p (arg, 0))
1039           tmp = wi::ctz (arg);
1040         else if (!CTZ_DEFINED_VALUE_AT_ZERO (SCALAR_INT_TYPE_MODE (arg_type),
1041                                              tmp))
1042           tmp = TYPE_PRECISION (arg_type);
1043         *result = wi::shwi (tmp, precision);
1044         return true;
1045       }
1046
1047     CASE_CFN_CLRSB:
1048       *result = wi::shwi (wi::clrsb (arg), precision);
1049       return true;
1050
1051     CASE_CFN_POPCOUNT:
1052       *result = wi::shwi (wi::popcount (arg), precision);
1053       return true;
1054
1055     CASE_CFN_PARITY:
1056       *result = wi::shwi (wi::parity (arg), precision);
1057       return true;
1058
1059     case CFN_BUILT_IN_BSWAP16:
1060     case CFN_BUILT_IN_BSWAP32:
1061     case CFN_BUILT_IN_BSWAP64:
1062     case CFN_BUILT_IN_BSWAP128:
1063       *result = wi::bswap (wide_int::from (arg, precision,
1064                                            TYPE_SIGN (arg_type)));
1065       return true;
1066
1067     default:
1068       return false;
1069     }
1070 }
1071
1072 /* Try to evaluate:
1073
1074       RESULT = FN (*ARG)
1075
1076    where FORMAT is the format of ARG and of the real and imaginary parts
1077    of RESULT, passed as RESULT_REAL and RESULT_IMAG respectively.  Return
1078    true on success.  */
1079
1080 static bool
1081 fold_const_call_cs (real_value *result_real, real_value *result_imag,
1082                     combined_fn fn, const real_value *arg,
1083                     const real_format *format)
1084 {
1085   switch (fn)
1086     {
1087     CASE_CFN_CEXPI:
1088       /* cexpi(x+yi) = cos(x)+sin(y)*i.  */
1089       return do_mpfr_sincos (result_imag, result_real, arg, format);
1090
1091     default:
1092       return false;
1093     }
1094 }
1095
1096 /* Try to evaluate:
1097
1098       *RESULT = fn (ARG)
1099
1100    where FORMAT is the format of RESULT and of the real and imaginary parts
1101    of ARG, passed as ARG_REAL and ARG_IMAG respectively.  Return true on
1102    success.  */
1103
1104 static bool
1105 fold_const_call_sc (real_value *result, combined_fn fn,
1106                     const real_value *arg_real, const real_value *arg_imag,
1107                     const real_format *format)
1108 {
1109   switch (fn)
1110     {
1111     CASE_CFN_CABS:
1112     CASE_CFN_CABS_FN:
1113       return do_mpfr_arg2 (result, mpfr_hypot, arg_real, arg_imag, format);
1114
1115     default:
1116       return false;
1117     }
1118 }
1119
1120 /* Try to evaluate:
1121
1122       RESULT = fn (ARG)
1123
1124    where FORMAT is the format of the real and imaginary parts of RESULT
1125    (RESULT_REAL and RESULT_IMAG) and of ARG (ARG_REAL and ARG_IMAG).
1126    Return true on success.  */
1127
1128 static bool
1129 fold_const_call_cc (real_value *result_real, real_value *result_imag,
1130                     combined_fn fn, const real_value *arg_real,
1131                     const real_value *arg_imag, const real_format *format)
1132 {
1133   switch (fn)
1134     {
1135     CASE_CFN_CCOS:
1136     CASE_CFN_CCOS_FN:
1137       return do_mpc_arg1 (result_real, result_imag, mpc_cos,
1138                           arg_real, arg_imag, format);
1139
1140     CASE_CFN_CCOSH:
1141     CASE_CFN_CCOSH_FN:
1142       return do_mpc_arg1 (result_real, result_imag, mpc_cosh,
1143                           arg_real, arg_imag, format);
1144
1145     CASE_CFN_CPROJ:
1146     CASE_CFN_CPROJ_FN:
1147       if (real_isinf (arg_real) || real_isinf (arg_imag))
1148         {
1149           *result_real = dconstinf;
1150           *result_imag = dconst0;
1151           result_imag->sign = arg_imag->sign;
1152         }
1153       else
1154         {
1155           *result_real = *arg_real;
1156           *result_imag = *arg_imag;
1157         }
1158       return true;
1159
1160     CASE_CFN_CSIN:
1161     CASE_CFN_CSIN_FN:
1162       return do_mpc_arg1 (result_real, result_imag, mpc_sin,
1163                           arg_real, arg_imag, format);
1164
1165     CASE_CFN_CSINH:
1166     CASE_CFN_CSINH_FN:
1167       return do_mpc_arg1 (result_real, result_imag, mpc_sinh,
1168                           arg_real, arg_imag, format);
1169
1170     CASE_CFN_CTAN:
1171     CASE_CFN_CTAN_FN:
1172       return do_mpc_arg1 (result_real, result_imag, mpc_tan,
1173                           arg_real, arg_imag, format);
1174
1175     CASE_CFN_CTANH:
1176     CASE_CFN_CTANH_FN:
1177       return do_mpc_arg1 (result_real, result_imag, mpc_tanh,
1178                           arg_real, arg_imag, format);
1179
1180     CASE_CFN_CLOG:
1181     CASE_CFN_CLOG_FN:
1182       return do_mpc_arg1 (result_real, result_imag, mpc_log,
1183                           arg_real, arg_imag, format);
1184
1185     CASE_CFN_CSQRT:
1186     CASE_CFN_CSQRT_FN:
1187       return do_mpc_arg1 (result_real, result_imag, mpc_sqrt,
1188                           arg_real, arg_imag, format);
1189
1190     CASE_CFN_CASIN:
1191     CASE_CFN_CASIN_FN:
1192       return do_mpc_arg1 (result_real, result_imag, mpc_asin,
1193                           arg_real, arg_imag, format);
1194
1195     CASE_CFN_CACOS:
1196     CASE_CFN_CACOS_FN:
1197       return do_mpc_arg1 (result_real, result_imag, mpc_acos,
1198                           arg_real, arg_imag, format);
1199
1200     CASE_CFN_CATAN:
1201     CASE_CFN_CATAN_FN:
1202       return do_mpc_arg1 (result_real, result_imag, mpc_atan,
1203                           arg_real, arg_imag, format);
1204
1205     CASE_CFN_CASINH:
1206     CASE_CFN_CASINH_FN:
1207       return do_mpc_arg1 (result_real, result_imag, mpc_asinh,
1208                           arg_real, arg_imag, format);
1209
1210     CASE_CFN_CACOSH:
1211     CASE_CFN_CACOSH_FN:
1212       return do_mpc_arg1 (result_real, result_imag, mpc_acosh,
1213                           arg_real, arg_imag, format);
1214
1215     CASE_CFN_CATANH:
1216     CASE_CFN_CATANH_FN:
1217       return do_mpc_arg1 (result_real, result_imag, mpc_atanh,
1218                           arg_real, arg_imag, format);
1219
1220     CASE_CFN_CEXP:
1221     CASE_CFN_CEXP_FN:
1222       return do_mpc_arg1 (result_real, result_imag, mpc_exp,
1223                           arg_real, arg_imag, format);
1224
1225     default:
1226       return false;
1227     }
1228 }
1229
1230 /* Subroutine of fold_const_call, with the same interface.  Handle cases
1231    where the arguments and result are numerical.  */
1232
1233 static tree
1234 fold_const_call_1 (combined_fn fn, tree type, tree arg)
1235 {
1236   machine_mode mode = TYPE_MODE (type);
1237   machine_mode arg_mode = TYPE_MODE (TREE_TYPE (arg));
1238
1239   if (integer_cst_p (arg))
1240     {
1241       if (SCALAR_INT_MODE_P (mode))
1242         {
1243           wide_int result;
1244           if (fold_const_call_ss (&result, fn, wi::to_wide (arg),
1245                                   TYPE_PRECISION (type), TREE_TYPE (arg)))
1246             return wide_int_to_tree (type, result);
1247         }
1248       return NULL_TREE;
1249     }
1250
1251   if (real_cst_p (arg))
1252     {
1253       gcc_checking_assert (SCALAR_FLOAT_MODE_P (arg_mode));
1254       if (mode == arg_mode)
1255         {
1256           /* real -> real.  */
1257           REAL_VALUE_TYPE result;
1258           if (fold_const_call_ss (&result, fn, TREE_REAL_CST_PTR (arg),
1259                                   REAL_MODE_FORMAT (mode)))
1260             return build_real (type, result);
1261         }
1262       else if (COMPLEX_MODE_P (mode)
1263                && GET_MODE_INNER (mode) == arg_mode)
1264         {
1265           /* real -> complex real.  */
1266           REAL_VALUE_TYPE result_real, result_imag;
1267           if (fold_const_call_cs (&result_real, &result_imag, fn,
1268                                   TREE_REAL_CST_PTR (arg),
1269                                   REAL_MODE_FORMAT (arg_mode)))
1270             return build_complex (type,
1271                                   build_real (TREE_TYPE (type), result_real),
1272                                   build_real (TREE_TYPE (type), result_imag));
1273         }
1274       else if (INTEGRAL_TYPE_P (type))
1275         {
1276           /* real -> int.  */
1277           wide_int result;
1278           if (fold_const_call_ss (&result, fn,
1279                                   TREE_REAL_CST_PTR (arg),
1280                                   TYPE_PRECISION (type),
1281                                   REAL_MODE_FORMAT (arg_mode)))
1282             return wide_int_to_tree (type, result);
1283         }
1284       return NULL_TREE;
1285     }
1286
1287   if (complex_cst_p (arg))
1288     {
1289       gcc_checking_assert (COMPLEX_MODE_P (arg_mode));
1290       machine_mode inner_mode = GET_MODE_INNER (arg_mode);
1291       tree argr = TREE_REALPART (arg);
1292       tree argi = TREE_IMAGPART (arg);
1293       if (mode == arg_mode
1294           && real_cst_p (argr)
1295           && real_cst_p (argi))
1296         {
1297           /* complex real -> complex real.  */
1298           REAL_VALUE_TYPE result_real, result_imag;
1299           if (fold_const_call_cc (&result_real, &result_imag, fn,
1300                                   TREE_REAL_CST_PTR (argr),
1301                                   TREE_REAL_CST_PTR (argi),
1302                                   REAL_MODE_FORMAT (inner_mode)))
1303             return build_complex (type,
1304                                   build_real (TREE_TYPE (type), result_real),
1305                                   build_real (TREE_TYPE (type), result_imag));
1306         }
1307       if (mode == inner_mode
1308           && real_cst_p (argr)
1309           && real_cst_p (argi))
1310         {
1311           /* complex real -> real.  */
1312           REAL_VALUE_TYPE result;
1313           if (fold_const_call_sc (&result, fn,
1314                                   TREE_REAL_CST_PTR (argr),
1315                                   TREE_REAL_CST_PTR (argi),
1316                                   REAL_MODE_FORMAT (inner_mode)))
1317             return build_real (type, result);
1318         }
1319       return NULL_TREE;
1320     }
1321
1322   return NULL_TREE;
1323 }
1324
1325 /* Try to fold FN (ARG) to a constant.  Return the constant on success,
1326    otherwise return null.  TYPE is the type of the return value.  */
1327
1328 tree
1329 fold_const_call (combined_fn fn, tree type, tree arg)
1330 {
1331   switch (fn)
1332     {
1333     case CFN_BUILT_IN_STRLEN:
1334       if (const char *str = c_getstr (arg))
1335         return build_int_cst (type, strlen (str));
1336       return NULL_TREE;
1337
1338     CASE_CFN_NAN:
1339     CASE_FLT_FN_FLOATN_NX (CFN_BUILT_IN_NAN):
1340     case CFN_BUILT_IN_NAND32:
1341     case CFN_BUILT_IN_NAND64:
1342     case CFN_BUILT_IN_NAND128:
1343       return fold_const_builtin_nan (type, arg, true);
1344
1345     CASE_CFN_NANS:
1346     CASE_FLT_FN_FLOATN_NX (CFN_BUILT_IN_NANS):
1347     case CFN_BUILT_IN_NANSF16B:
1348     case CFN_BUILT_IN_NANSD32:
1349     case CFN_BUILT_IN_NANSD64:
1350     case CFN_BUILT_IN_NANSD128:
1351       return fold_const_builtin_nan (type, arg, false);
1352
1353     case CFN_REDUC_PLUS:
1354       return fold_const_reduction (type, arg, PLUS_EXPR);
1355
1356     case CFN_REDUC_MAX:
1357       return fold_const_reduction (type, arg, MAX_EXPR);
1358
1359     case CFN_REDUC_MIN:
1360       return fold_const_reduction (type, arg, MIN_EXPR);
1361
1362     case CFN_REDUC_AND:
1363       return fold_const_reduction (type, arg, BIT_AND_EXPR);
1364
1365     case CFN_REDUC_IOR:
1366       return fold_const_reduction (type, arg, BIT_IOR_EXPR);
1367
1368     case CFN_REDUC_XOR:
1369       return fold_const_reduction (type, arg, BIT_XOR_EXPR);
1370
1371     case CFN_VEC_CONVERT:
1372       return fold_const_vec_convert (type, arg);
1373
1374     default:
1375       return fold_const_call_1 (fn, type, arg);
1376     }
1377 }
1378
1379 /* Fold a call to IFN_FOLD_LEFT_<CODE> (ARG0, ARG1), returning a value
1380    of type TYPE.  */
1381
1382 static tree
1383 fold_const_fold_left (tree type, tree arg0, tree arg1, tree_code code)
1384 {
1385   if (TREE_CODE (arg1) != VECTOR_CST)
1386     return NULL_TREE;
1387
1388   unsigned HOST_WIDE_INT nelts;
1389   if (!VECTOR_CST_NELTS (arg1).is_constant (&nelts))
1390     return NULL_TREE;
1391
1392   for (unsigned HOST_WIDE_INT i = 0; i < nelts; i++)
1393     {
1394       arg0 = const_binop (code, type, arg0, VECTOR_CST_ELT (arg1, i));
1395       if (arg0 == NULL_TREE || !CONSTANT_CLASS_P (arg0))
1396         return NULL_TREE;
1397     }
1398   return arg0;
1399 }
1400
1401 /* Try to evaluate:
1402
1403       *RESULT = FN (*ARG0, *ARG1)
1404
1405    in format FORMAT.  Return true on success.  */
1406
1407 static bool
1408 fold_const_call_sss (real_value *result, combined_fn fn,
1409                      const real_value *arg0, const real_value *arg1,
1410                      const real_format *format)
1411 {
1412   switch (fn)
1413     {
1414     CASE_CFN_DREM:
1415     CASE_CFN_REMAINDER:
1416     CASE_CFN_REMAINDER_FN:
1417       return do_mpfr_arg2 (result, mpfr_remainder, arg0, arg1, format);
1418
1419     CASE_CFN_ATAN2:
1420     CASE_CFN_ATAN2_FN:
1421       return do_mpfr_arg2 (result, mpfr_atan2, arg0, arg1, format);
1422
1423     CASE_CFN_FDIM:
1424     CASE_CFN_FDIM_FN:
1425       return do_mpfr_arg2 (result, mpfr_dim, arg0, arg1, format);
1426
1427     CASE_CFN_FMOD:
1428     CASE_CFN_FMOD_FN:
1429       return do_mpfr_arg2 (result, mpfr_fmod, arg0, arg1, format);
1430
1431     CASE_CFN_HYPOT:
1432     CASE_CFN_HYPOT_FN:
1433       return do_mpfr_arg2 (result, mpfr_hypot, arg0, arg1, format);
1434
1435     CASE_CFN_COPYSIGN:
1436     CASE_CFN_COPYSIGN_FN:
1437       *result = *arg0;
1438       real_copysign (result, arg1);
1439       return true;
1440
1441     CASE_CFN_FMIN:
1442     CASE_CFN_FMIN_FN:
1443       return do_mpfr_arg2 (result, mpfr_min, arg0, arg1, format);
1444
1445     CASE_CFN_FMAX:
1446     CASE_CFN_FMAX_FN:
1447       return do_mpfr_arg2 (result, mpfr_max, arg0, arg1, format);
1448
1449     CASE_CFN_POW:
1450     CASE_CFN_POW_FN:
1451       return fold_const_pow (result, arg0, arg1, format);
1452
1453     CASE_CFN_NEXTAFTER:
1454     CASE_CFN_NEXTAFTER_FN:
1455     case CFN_BUILT_IN_NEXTAFTERF16B:
1456     CASE_CFN_NEXTTOWARD:
1457       return fold_const_nextafter (result, arg0, arg1, format);
1458
1459     default:
1460       return false;
1461     }
1462 }
1463
1464 /* Try to evaluate:
1465
1466       *RESULT = FN (*ARG0, ARG1)
1467
1468    where FORMAT is the format of *RESULT and *ARG0.  Return true on
1469    success.  */
1470
1471 static bool
1472 fold_const_call_sss (real_value *result, combined_fn fn,
1473                      const real_value *arg0, const wide_int_ref &arg1,
1474                      const real_format *format)
1475 {
1476   switch (fn)
1477     {
1478     CASE_CFN_LDEXP:
1479     CASE_CFN_LDEXP_FN:
1480       return fold_const_builtin_load_exponent (result, arg0, arg1, format);
1481
1482     CASE_CFN_SCALBN:
1483     CASE_CFN_SCALBN_FN:
1484     CASE_CFN_SCALBLN:
1485     CASE_CFN_SCALBLN_FN:
1486       return (format->b == 2
1487               && fold_const_builtin_load_exponent (result, arg0, arg1,
1488                                                    format));
1489
1490     CASE_CFN_POWI:
1491       /* Avoid the folding if flag_signaling_nans is on and
1492          operand is a signaling NaN.  */
1493       if (!flag_unsafe_math_optimizations
1494           && flag_signaling_nans
1495           && REAL_VALUE_ISSIGNALING_NAN (*arg0))
1496         return false;
1497
1498       real_powi (result, format, arg0, arg1.to_shwi ());
1499       return true;
1500
1501     default:
1502       return false;
1503     }
1504 }
1505
1506 /* Try to evaluate:
1507
1508       *RESULT = FN (ARG0, *ARG1)
1509
1510    where FORMAT is the format of *RESULT and *ARG1.  Return true on
1511    success.  */
1512
1513 static bool
1514 fold_const_call_sss (real_value *result, combined_fn fn,
1515                      const wide_int_ref &arg0, const real_value *arg1,
1516                      const real_format *format)
1517 {
1518   switch (fn)
1519     {
1520     CASE_CFN_JN:
1521       return do_mpfr_arg2 (result, mpfr_jn, arg0, arg1, format);
1522
1523     CASE_CFN_YN:
1524       return (real_compare (GT_EXPR, arg1, &dconst0)
1525               && do_mpfr_arg2 (result, mpfr_yn, arg0, arg1, format));
1526
1527     default:
1528       return false;
1529     }
1530 }
1531
1532 /* Try to evaluate:
1533
1534       RESULT = fn (ARG0, ARG1)
1535
1536    where FORMAT is the format of the real and imaginary parts of RESULT
1537    (RESULT_REAL and RESULT_IMAG), of ARG0 (ARG0_REAL and ARG0_IMAG)
1538    and of ARG1 (ARG1_REAL and ARG1_IMAG).  Return true on success.  */
1539
1540 static bool
1541 fold_const_call_ccc (real_value *result_real, real_value *result_imag,
1542                      combined_fn fn, const real_value *arg0_real,
1543                      const real_value *arg0_imag, const real_value *arg1_real,
1544                      const real_value *arg1_imag, const real_format *format)
1545 {
1546   switch (fn)
1547     {
1548     CASE_CFN_CPOW:
1549     CASE_CFN_CPOW_FN:
1550       return do_mpc_arg2 (result_real, result_imag, mpc_pow,
1551                           arg0_real, arg0_imag, arg1_real, arg1_imag, format);
1552
1553     default:
1554       return false;
1555     }
1556 }
1557
1558 /* Subroutine of fold_const_call, with the same interface.  Handle cases
1559    where the arguments and result are numerical.  */
1560
1561 static tree
1562 fold_const_call_1 (combined_fn fn, tree type, tree arg0, tree arg1)
1563 {
1564   machine_mode mode = TYPE_MODE (type);
1565   machine_mode arg0_mode = TYPE_MODE (TREE_TYPE (arg0));
1566   machine_mode arg1_mode = TYPE_MODE (TREE_TYPE (arg1));
1567
1568   if (mode == arg0_mode
1569       && real_cst_p (arg0)
1570       && real_cst_p (arg1))
1571     {
1572       gcc_checking_assert (SCALAR_FLOAT_MODE_P (arg0_mode));
1573       REAL_VALUE_TYPE result;
1574       if (arg0_mode == arg1_mode)
1575         {
1576           /* real, real -> real.  */
1577           if (fold_const_call_sss (&result, fn, TREE_REAL_CST_PTR (arg0),
1578                                    TREE_REAL_CST_PTR (arg1),
1579                                    REAL_MODE_FORMAT (mode)))
1580             return build_real (type, result);
1581         }
1582       else if (arg1_mode == TYPE_MODE (long_double_type_node))
1583         switch (fn)
1584           {
1585           CASE_CFN_NEXTTOWARD:
1586             /* real, long double -> real.  */
1587             if (fold_const_call_sss (&result, fn, TREE_REAL_CST_PTR (arg0),
1588                                      TREE_REAL_CST_PTR (arg1),
1589                                      REAL_MODE_FORMAT (mode)))
1590               return build_real (type, result);
1591             break;
1592           default:
1593             break;
1594           }
1595       return NULL_TREE;
1596     }
1597
1598   if (real_cst_p (arg0)
1599       && integer_cst_p (arg1))
1600     {
1601       gcc_checking_assert (SCALAR_FLOAT_MODE_P (arg0_mode));
1602       if (mode == arg0_mode)
1603         {
1604           /* real, int -> real.  */
1605           REAL_VALUE_TYPE result;
1606           if (fold_const_call_sss (&result, fn, TREE_REAL_CST_PTR (arg0),
1607                                    wi::to_wide (arg1),
1608                                    REAL_MODE_FORMAT (mode)))
1609             return build_real (type, result);
1610         }
1611       return NULL_TREE;
1612     }
1613
1614   if (integer_cst_p (arg0)
1615       && real_cst_p (arg1))
1616     {
1617       gcc_checking_assert (SCALAR_FLOAT_MODE_P (arg1_mode));
1618       if (mode == arg1_mode)
1619         {
1620           /* int, real -> real.  */
1621           REAL_VALUE_TYPE result;
1622           if (fold_const_call_sss (&result, fn, wi::to_wide (arg0),
1623                                    TREE_REAL_CST_PTR (arg1),
1624                                    REAL_MODE_FORMAT (mode)))
1625             return build_real (type, result);
1626         }
1627       return NULL_TREE;
1628     }
1629
1630   if (arg0_mode == arg1_mode
1631       && complex_cst_p (arg0)
1632       && complex_cst_p (arg1))
1633     {
1634       gcc_checking_assert (COMPLEX_MODE_P (arg0_mode));
1635       machine_mode inner_mode = GET_MODE_INNER (arg0_mode);
1636       tree arg0r = TREE_REALPART (arg0);
1637       tree arg0i = TREE_IMAGPART (arg0);
1638       tree arg1r = TREE_REALPART (arg1);
1639       tree arg1i = TREE_IMAGPART (arg1);
1640       if (mode == arg0_mode
1641           && real_cst_p (arg0r)
1642           && real_cst_p (arg0i)
1643           && real_cst_p (arg1r)
1644           && real_cst_p (arg1i))
1645         {
1646           /* complex real, complex real -> complex real.  */
1647           REAL_VALUE_TYPE result_real, result_imag;
1648           if (fold_const_call_ccc (&result_real, &result_imag, fn,
1649                                    TREE_REAL_CST_PTR (arg0r),
1650                                    TREE_REAL_CST_PTR (arg0i),
1651                                    TREE_REAL_CST_PTR (arg1r),
1652                                    TREE_REAL_CST_PTR (arg1i),
1653                                    REAL_MODE_FORMAT (inner_mode)))
1654             return build_complex (type,
1655                                   build_real (TREE_TYPE (type), result_real),
1656                                   build_real (TREE_TYPE (type), result_imag));
1657         }
1658       return NULL_TREE;
1659     }
1660
1661   return NULL_TREE;
1662 }
1663
1664 /* Try to fold FN (ARG0, ARG1) to a constant.  Return the constant on success,
1665    otherwise return null.  TYPE is the type of the return value.  */
1666
1667 tree
1668 fold_const_call (combined_fn fn, tree type, tree arg0, tree arg1)
1669 {
1670   const char *p0, *p1;
1671   char c;
1672   tree_code subcode;
1673   switch (fn)
1674     {
1675     case CFN_BUILT_IN_STRSPN:
1676       if ((p0 = c_getstr (arg0)) && (p1 = c_getstr (arg1)))
1677         return build_int_cst (type, strspn (p0, p1));
1678       return NULL_TREE;
1679
1680     case CFN_BUILT_IN_STRCSPN:
1681       if ((p0 = c_getstr (arg0)) && (p1 = c_getstr (arg1)))
1682         return build_int_cst (type, strcspn (p0, p1));
1683       return NULL_TREE;
1684
1685     case CFN_BUILT_IN_STRCMP:
1686       if ((p0 = c_getstr (arg0)) && (p1 = c_getstr (arg1)))
1687         return build_cmp_result (type, strcmp (p0, p1));
1688       return NULL_TREE;
1689
1690     case CFN_BUILT_IN_STRCASECMP:
1691       if ((p0 = c_getstr (arg0)) && (p1 = c_getstr (arg1)))
1692         {
1693           int r = strcmp (p0, p1);
1694           if (r == 0)
1695             return build_cmp_result (type, r);
1696         }
1697       return NULL_TREE;
1698
1699     case CFN_BUILT_IN_INDEX:
1700     case CFN_BUILT_IN_STRCHR:
1701       if ((p0 = c_getstr (arg0)) && target_char_cst_p (arg1, &c))
1702         {
1703           const char *r = strchr (p0, c);
1704           if (r == NULL)
1705             return build_int_cst (type, 0);
1706           return fold_convert (type,
1707                                fold_build_pointer_plus_hwi (arg0, r - p0));
1708         }
1709       return NULL_TREE;
1710
1711     case CFN_BUILT_IN_RINDEX:
1712     case CFN_BUILT_IN_STRRCHR:
1713       if ((p0 = c_getstr (arg0)) && target_char_cst_p (arg1, &c))
1714         {
1715           const char *r = strrchr (p0, c);
1716           if (r == NULL)
1717             return build_int_cst (type, 0);
1718           return fold_convert (type,
1719                                fold_build_pointer_plus_hwi (arg0, r - p0));
1720         }
1721       return NULL_TREE;
1722
1723     case CFN_BUILT_IN_STRSTR:
1724       if ((p1 = c_getstr (arg1)))
1725         {
1726           if ((p0 = c_getstr (arg0)))
1727             {
1728               const char *r = strstr (p0, p1);
1729               if (r == NULL)
1730                 return build_int_cst (type, 0);
1731               return fold_convert (type,
1732                                    fold_build_pointer_plus_hwi (arg0, r - p0));
1733             }
1734           if (*p1 == '\0')
1735             return fold_convert (type, arg0);
1736         }
1737       return NULL_TREE;
1738
1739     case CFN_FOLD_LEFT_PLUS:
1740       return fold_const_fold_left (type, arg0, arg1, PLUS_EXPR);
1741
1742     case CFN_UBSAN_CHECK_ADD:
1743     case CFN_ADD_OVERFLOW:
1744       subcode = PLUS_EXPR;
1745       goto arith_overflow;
1746
1747     case CFN_UBSAN_CHECK_SUB:
1748     case CFN_SUB_OVERFLOW:
1749       subcode = MINUS_EXPR;
1750       goto arith_overflow;
1751
1752     case CFN_UBSAN_CHECK_MUL:
1753     case CFN_MUL_OVERFLOW:
1754       subcode = MULT_EXPR;
1755       goto arith_overflow;
1756
1757     arith_overflow:
1758       if (integer_cst_p (arg0) && integer_cst_p (arg1))
1759         {
1760           tree itype
1761             = TREE_CODE (type) == COMPLEX_TYPE ? TREE_TYPE (type) : type;
1762           bool ovf = false;
1763           tree r = int_const_binop (subcode, fold_convert (itype, arg0),
1764                                     fold_convert (itype, arg1));
1765           if (!r || TREE_CODE (r) != INTEGER_CST)
1766             return NULL_TREE;
1767           if (arith_overflowed_p (subcode, itype, arg0, arg1))
1768             ovf = true;
1769           if (TREE_OVERFLOW (r))
1770             r = drop_tree_overflow (r);
1771           if (itype == type)
1772             {
1773               if (ovf)
1774                 return NULL_TREE;
1775               return r;
1776             }
1777           else
1778             return build_complex (type, r, build_int_cst (itype, ovf));
1779         }
1780       return NULL_TREE;
1781
1782     default:
1783       return fold_const_call_1 (fn, type, arg0, arg1);
1784     }
1785 }
1786
1787 /* Try to evaluate:
1788
1789       *RESULT = FN (*ARG0, *ARG1, *ARG2)
1790
1791    in format FORMAT.  Return true on success.  */
1792
1793 static bool
1794 fold_const_call_ssss (real_value *result, combined_fn fn,
1795                       const real_value *arg0, const real_value *arg1,
1796                       const real_value *arg2, const real_format *format)
1797 {
1798   switch (fn)
1799     {
1800     CASE_CFN_FMA:
1801     CASE_CFN_FMA_FN:
1802       return do_mpfr_arg3 (result, mpfr_fma, arg0, arg1, arg2, format);
1803
1804     case CFN_FMS:
1805       {
1806         real_value new_arg2 = real_value_negate (arg2);
1807         return do_mpfr_arg3 (result, mpfr_fma, arg0, arg1, &new_arg2, format);
1808       }
1809
1810     case CFN_FNMA:
1811       {
1812         real_value new_arg0 = real_value_negate (arg0);
1813         return do_mpfr_arg3 (result, mpfr_fma, &new_arg0, arg1, arg2, format);
1814       }
1815
1816     case CFN_FNMS:
1817       {
1818         real_value new_arg0 = real_value_negate (arg0);
1819         real_value new_arg2 = real_value_negate (arg2);
1820         return do_mpfr_arg3 (result, mpfr_fma, &new_arg0, arg1,
1821                              &new_arg2, format);
1822       }
1823
1824     default:
1825       return false;
1826     }
1827 }
1828
1829 /* Subroutine of fold_const_call, with the same interface.  Handle cases
1830    where the arguments and result are numerical.  */
1831
1832 static tree
1833 fold_const_call_1 (combined_fn fn, tree type, tree arg0, tree arg1, tree arg2)
1834 {
1835   machine_mode mode = TYPE_MODE (type);
1836   machine_mode arg0_mode = TYPE_MODE (TREE_TYPE (arg0));
1837   machine_mode arg1_mode = TYPE_MODE (TREE_TYPE (arg1));
1838   machine_mode arg2_mode = TYPE_MODE (TREE_TYPE (arg2));
1839
1840   if (arg0_mode == arg1_mode
1841       && arg0_mode == arg2_mode
1842       && real_cst_p (arg0)
1843       && real_cst_p (arg1)
1844       && real_cst_p (arg2))
1845     {
1846       gcc_checking_assert (SCALAR_FLOAT_MODE_P (arg0_mode));
1847       if (mode == arg0_mode)
1848         {
1849           /* real, real, real -> real.  */
1850           REAL_VALUE_TYPE result;
1851           if (fold_const_call_ssss (&result, fn, TREE_REAL_CST_PTR (arg0),
1852                                     TREE_REAL_CST_PTR (arg1),
1853                                     TREE_REAL_CST_PTR (arg2),
1854                                     REAL_MODE_FORMAT (mode)))
1855             return build_real (type, result);
1856         }
1857       return NULL_TREE;
1858     }
1859
1860   return NULL_TREE;
1861 }
1862
1863 /* Try to fold FN (ARG0, ARG1, ARG2) to a constant.  Return the constant on
1864    success, otherwise return null.  TYPE is the type of the return value.  */
1865
1866 tree
1867 fold_const_call (combined_fn fn, tree type, tree arg0, tree arg1, tree arg2)
1868 {
1869   const char *p0, *p1;
1870   char c;
1871   unsigned HOST_WIDE_INT s0, s1, s2 = 0;
1872   switch (fn)
1873     {
1874     case CFN_BUILT_IN_STRNCMP:
1875       if (!size_t_cst_p (arg2, &s2))
1876         return NULL_TREE;
1877       if (s2 == 0
1878           && !TREE_SIDE_EFFECTS (arg0)
1879           && !TREE_SIDE_EFFECTS (arg1))
1880         return build_int_cst (type, 0);
1881       else if ((p0 = c_getstr (arg0)) && (p1 = c_getstr (arg1)))
1882         return build_int_cst (type, strncmp (p0, p1, MIN (s2, SIZE_MAX)));
1883       return NULL_TREE;
1884
1885     case CFN_BUILT_IN_STRNCASECMP:
1886       if (!size_t_cst_p (arg2, &s2))
1887         return NULL_TREE;
1888       if (s2 == 0
1889           && !TREE_SIDE_EFFECTS (arg0)
1890           && !TREE_SIDE_EFFECTS (arg1))
1891         return build_int_cst (type, 0);
1892       else if ((p0 = c_getstr (arg0))
1893                && (p1 = c_getstr (arg1))
1894                && strncmp (p0, p1, MIN (s2, SIZE_MAX)) == 0)
1895         return build_int_cst (type, 0);
1896       return NULL_TREE;
1897
1898     case CFN_BUILT_IN_BCMP:
1899     case CFN_BUILT_IN_MEMCMP:
1900       if (!size_t_cst_p (arg2, &s2))
1901         return NULL_TREE;
1902       if (s2 == 0
1903           && !TREE_SIDE_EFFECTS (arg0)
1904           && !TREE_SIDE_EFFECTS (arg1))
1905         return build_int_cst (type, 0);
1906       if ((p0 = getbyterep (arg0, &s0))
1907           && (p1 = getbyterep (arg1, &s1))
1908           && s2 <= s0
1909           && s2 <= s1)
1910         return build_cmp_result (type, memcmp (p0, p1, s2));
1911       return NULL_TREE;
1912
1913     case CFN_BUILT_IN_MEMCHR:
1914       if (!size_t_cst_p (arg2, &s2))
1915         return NULL_TREE;
1916       if (s2 == 0
1917           && !TREE_SIDE_EFFECTS (arg0)
1918           && !TREE_SIDE_EFFECTS (arg1))
1919         return build_int_cst (type, 0);
1920       if ((p0 = getbyterep (arg0, &s0))
1921           && s2 <= s0
1922           && target_char_cst_p (arg1, &c))
1923         {
1924           const char *r = (const char *) memchr (p0, c, s2);
1925           if (r == NULL)
1926             return build_int_cst (type, 0);
1927           return fold_convert (type,
1928                                fold_build_pointer_plus_hwi (arg0, r - p0));
1929         }
1930       return NULL_TREE;
1931
1932     case CFN_WHILE_ULT:
1933       {
1934         poly_uint64 parg0, parg1;
1935         if (poly_int_tree_p (arg0, &parg0) && poly_int_tree_p (arg1, &parg1))
1936           return fold_while_ult (type, parg0, parg1);
1937         return NULL_TREE;
1938       }
1939
1940     case CFN_UADDC:
1941     case CFN_USUBC:
1942       if (integer_cst_p (arg0) && integer_cst_p (arg1) && integer_cst_p (arg2))
1943         {
1944           tree itype = TREE_TYPE (type);
1945           bool ovf = false;
1946           tree_code subcode = fn == CFN_UADDC ? PLUS_EXPR : MINUS_EXPR;
1947           tree r = int_const_binop (subcode, fold_convert (itype, arg0),
1948                                     fold_convert (itype, arg1));
1949           if (!r)
1950             return NULL_TREE;
1951           if (arith_overflowed_p (subcode, itype, arg0, arg1))
1952             ovf = true;
1953           tree r2 = int_const_binop (subcode, r, fold_convert (itype, arg2));
1954           if (!r2 || TREE_CODE (r2) != INTEGER_CST)
1955             return NULL_TREE;
1956           if (arith_overflowed_p (subcode, itype, r, arg2))
1957             ovf = true;
1958           if (TREE_OVERFLOW (r2))
1959             r2 = drop_tree_overflow (r2);
1960           return build_complex (type, r2, build_int_cst (itype, ovf));
1961         }
1962       return NULL_TREE;
1963
1964     default:
1965       return fold_const_call_1 (fn, type, arg0, arg1, arg2);
1966     }
1967 }