gcc/fold-const-call.c

   1 /* Constant folding for calls to built-in and internal functions.
   2    Copyright (C) 1988-2021 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 mpft_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   mpfr_t m;
 134
 135   mpfr_init2 (m, prec);
 136   mpfr_from_real (m, arg, MPFR_RNDN);
 137   mpfr_clear_flags ();
 138   bool inexact = func (m, m, rnd);
 139   bool ok = do_mpfr_ckconv (result, m, inexact, format);
 140   mpfr_clear (m);
 141
 142   return ok;
 143 }
 144
 145 /* Try to evaluate:
 146
 147       *RESULT_SIN = sin (*ARG);
 148       *RESULT_COS = cos (*ARG);
 149
 150    for format FORMAT.  Return true on success.  */
 151
 152 static bool
 153 do_mpfr_sincos (real_value *result_sin, real_value *result_cos,
 154                 const real_value *arg, const real_format *format)
 155 {
 156   /* To proceed, MPFR must exactly represent the target floating point
 157      format, which only happens when the target base equals two.  */
 158   if (format->b != 2 || !real_isfinite (arg))
 159     return false;
 160
 161   int prec = format->p;
 162   mpfr_rnd_t rnd = format->round_towards_zero ? MPFR_RNDZ : MPFR_RNDN;
 163   mpfr_t m, ms, mc;
 164
 165   mpfr_inits2 (prec, m, ms, mc, NULL);
 166   mpfr_from_real (m, arg, MPFR_RNDN);
 167   mpfr_clear_flags ();
 168   bool inexact = mpfr_sin_cos (ms, mc, m, rnd);
 169   bool ok = (do_mpfr_ckconv (result_sin, ms, inexact, format)
 170              && do_mpfr_ckconv (result_cos, mc, inexact, format));
 171   mpfr_clears (m, ms, mc, NULL);
 172
 173   return ok;
 174 }
 175
 176 /* Try to evaluate:
 177
 178       *RESULT = f (*ARG0, *ARG1)
 179
 180    in format FORMAT, given that FUNC is the MPFR implementation of f.
 181    Return true on success.  */
 182
 183 static bool
 184 do_mpfr_arg2 (real_value *result,
 185               int (*func) (mpfr_ptr, mpfr_srcptr, mpfr_srcptr, mpfr_rnd_t),
 186               const real_value *arg0, const real_value *arg1,
 187               const real_format *format)
 188 {
 189   /* To proceed, MPFR must exactly represent the target floating point
 190      format, which only happens when the target base equals two.  */
 191   if (format->b != 2 || !real_isfinite (arg0) || !real_isfinite (arg1))
 192     return false;
 193
 194   int prec = format->p;
 195   mpfr_rnd_t rnd = format->round_towards_zero ? MPFR_RNDZ : MPFR_RNDN;
 196   mpfr_t m0, m1;
 197
 198   mpfr_inits2 (prec, m0, m1, NULL);
 199   mpfr_from_real (m0, arg0, MPFR_RNDN);
 200   mpfr_from_real (m1, arg1, MPFR_RNDN);
 201   mpfr_clear_flags ();
 202   bool inexact = func (m0, m0, m1, rnd);
 203   bool ok = do_mpfr_ckconv (result, m0, inexact, format);
 204   mpfr_clears (m0, m1, NULL);
 205
 206   return ok;
 207 }
 208
 209 /* Try to evaluate:
 210
 211       *RESULT = f (ARG0, *ARG1)
 212
 213    in format FORMAT, given that FUNC is the MPFR implementation of f.
 214    Return true on success.  */
 215
 216 static bool
 217 do_mpfr_arg2 (real_value *result,
 218               int (*func) (mpfr_ptr, long, mpfr_srcptr, mpfr_rnd_t),
 219               const wide_int_ref &arg0, const real_value *arg1,
 220               const real_format *format)
 221 {
 222   if (format->b != 2 || !real_isfinite (arg1))
 223     return false;
 224
 225   int prec = format->p;
 226   mpfr_rnd_t rnd = format->round_towards_zero ? MPFR_RNDZ : MPFR_RNDN;
 227   mpfr_t m;
 228
 229   mpfr_init2 (m, prec);
 230   mpfr_from_real (m, arg1, MPFR_RNDN);
 231   mpfr_clear_flags ();
 232   bool inexact = func (m, arg0.to_shwi (), m, rnd);
 233   bool ok = do_mpfr_ckconv (result, m, inexact, format);
 234   mpfr_clear (m);
 235
 236   return ok;
 237 }
 238
 239 /* Try to evaluate:
 240
 241       *RESULT = f (*ARG0, *ARG1, *ARG2)
 242
 243    in format FORMAT, given that FUNC is the MPFR implementation of f.
 244    Return true on success.  */
 245
 246 static bool
 247 do_mpfr_arg3 (real_value *result,
 248               int (*func) (mpfr_ptr, mpfr_srcptr, mpfr_srcptr,
 249                            mpfr_srcptr, mpfr_rnd_t),
 250               const real_value *arg0, const real_value *arg1,
 251               const real_value *arg2, const real_format *format)
 252 {
 253   /* To proceed, MPFR must exactly represent the target floating point
 254      format, which only happens when the target base equals two.  */
 255   if (format->b != 2
 256       || !real_isfinite (arg0)
 257       || !real_isfinite (arg1)
 258       || !real_isfinite (arg2))
 259     return false;
 260
 261   int prec = format->p;
 262   mpfr_rnd_t rnd = format->round_towards_zero ? MPFR_RNDZ : MPFR_RNDN;
 263   mpfr_t m0, m1, m2;
 264
 265   mpfr_inits2 (prec, m0, m1, m2, NULL);
 266   mpfr_from_real (m0, arg0, MPFR_RNDN);
 267   mpfr_from_real (m1, arg1, MPFR_RNDN);
 268   mpfr_from_real (m2, arg2, MPFR_RNDN);
 269   mpfr_clear_flags ();
 270   bool inexact = func (m0, m0, m1, m2, rnd);
 271   bool ok = do_mpfr_ckconv (result, m0, inexact, format);
 272   mpfr_clears (m0, m1, m2, NULL);
 273
 274   return ok;
 275 }
 276
 277 /* M is the result of trying to constant-fold an expression (starting
 278    with clear MPFR flags) and INEXACT says whether the result in M is
 279    exact or inexact.  Return true if M can be used as a constant-folded
 280    result in which the real and imaginary parts have format FORMAT.
 281    Store those parts in *RESULT_REAL and *RESULT_IMAG if so.  */
 282
 283 static bool
 284 do_mpc_ckconv (real_value *result_real, real_value *result_imag,
 285                mpc_srcptr m, bool inexact, const real_format *format)
 286 {
 287   /* Proceed iff we get a normal number, i.e. not NaN or Inf and no
 288      overflow/underflow occurred.  If -frounding-math, proceed iff the
 289      result of calling FUNC was exact.  */
 290   if (!mpfr_number_p (mpc_realref (m))
 291       || !mpfr_number_p (mpc_imagref (m))
 292       || mpfr_overflow_p ()
 293       || mpfr_underflow_p ()
 294       || (flag_rounding_math && inexact))
 295     return false;
 296
 297   REAL_VALUE_TYPE tmp_real, tmp_imag;
 298   real_from_mpfr (&tmp_real, mpc_realref (m), format, MPFR_RNDN);
 299   real_from_mpfr (&tmp_imag, mpc_imagref (m), format, MPFR_RNDN);
 300
 301   /* Proceed iff GCC's REAL_VALUE_TYPE can hold the MPFR values.
 302      If the REAL_VALUE_TYPE is zero but the mpft_t is not, then we
 303      underflowed in the conversion.  */
 304   if (!real_isfinite (&tmp_real)
 305       || !real_isfinite (&tmp_imag)
 306       || (tmp_real.cl == rvc_zero) != (mpfr_zero_p (mpc_realref (m)) != 0)
 307       || (tmp_imag.cl == rvc_zero) != (mpfr_zero_p (mpc_imagref (m)) != 0))
 308     return false;
 309
 310   real_convert (result_real, format, &tmp_real);
 311   real_convert (result_imag, format, &tmp_imag);
 312
 313   return (real_identical (result_real, &tmp_real)
 314           && real_identical (result_imag, &tmp_imag));
 315 }
 316
 317 /* Try to evaluate:
 318
 319       RESULT = f (ARG)
 320
 321    in format FORMAT, given that FUNC is the mpc implementation of f.
 322    Return true on success.  Both RESULT and ARG are represented as
 323    real and imaginary pairs.  */
 324
 325 static bool
 326 do_mpc_arg1 (real_value *result_real, real_value *result_imag,
 327              int (*func) (mpc_ptr, mpc_srcptr, mpc_rnd_t),
 328              const real_value *arg_real, const real_value *arg_imag,
 329              const real_format *format)
 330 {
 331   /* To proceed, MPFR must exactly represent the target floating point
 332      format, which only happens when the target base equals two.  */
 333   if (format->b != 2
 334       || !real_isfinite (arg_real)
 335       || !real_isfinite (arg_imag))
 336     return false;
 337
 338   int prec = format->p;
 339   mpc_rnd_t crnd = format->round_towards_zero ? MPC_RNDZZ : MPC_RNDNN;
 340   mpc_t m;
 341
 342   mpc_init2 (m, prec);
 343   mpfr_from_real (mpc_realref (m), arg_real, MPFR_RNDN);
 344   mpfr_from_real (mpc_imagref (m), arg_imag, MPFR_RNDN);
 345   mpfr_clear_flags ();
 346   bool inexact = func (m, m, crnd);
 347   bool ok = do_mpc_ckconv (result_real, result_imag, m, inexact, format);
 348   mpc_clear (m);
 349
 350   return ok;
 351 }
 352
 353 /* Try to evaluate:
 354
 355       RESULT = f (ARG0, ARG1)
 356
 357    in format FORMAT, given that FUNC is the mpc implementation of f.
 358    Return true on success.  RESULT, ARG0 and ARG1 are represented as
 359    real and imaginary pairs.  */
 360
 361 static bool
 362 do_mpc_arg2 (real_value *result_real, real_value *result_imag,
 363              int (*func)(mpc_ptr, mpc_srcptr, mpc_srcptr, mpc_rnd_t),
 364              const real_value *arg0_real, const real_value *arg0_imag,
 365              const real_value *arg1_real, const real_value *arg1_imag,
 366              const real_format *format)
 367 {
 368   if (!real_isfinite (arg0_real)
 369       || !real_isfinite (arg0_imag)
 370       || !real_isfinite (arg1_real)
 371       || !real_isfinite (arg1_imag))
 372     return false;
 373
 374   int prec = format->p;
 375   mpc_rnd_t crnd = format->round_towards_zero ? MPC_RNDZZ : MPC_RNDNN;
 376   mpc_t m0, m1;
 377
 378   mpc_init2 (m0, prec);
 379   mpc_init2 (m1, prec);
 380   mpfr_from_real (mpc_realref (m0), arg0_real, MPFR_RNDN);
 381   mpfr_from_real (mpc_imagref (m0), arg0_imag, MPFR_RNDN);
 382   mpfr_from_real (mpc_realref (m1), arg1_real, MPFR_RNDN);
 383   mpfr_from_real (mpc_imagref (m1), arg1_imag, MPFR_RNDN);
 384   mpfr_clear_flags ();
 385   bool inexact = func (m0, m0, m1, crnd);
 386   bool ok = do_mpc_ckconv (result_real, result_imag, m0, inexact, format);
 387   mpc_clear (m0);
 388   mpc_clear (m1);
 389
 390   return ok;
 391 }
 392
 393 /* Try to evaluate:
 394
 395       *RESULT = logb (*ARG)
 396
 397    in format FORMAT.  Return true on success.  */
 398
 399 static bool
 400 fold_const_logb (real_value *result, const real_value *arg,
 401                  const real_format *format)
 402 {
 403   switch (arg->cl)
 404     {
 405     case rvc_nan:
 406       /* If arg is +-NaN, then return it.  */
 407       *result = *arg;
 408       return true;
 409
 410     case rvc_inf:
 411       /* If arg is +-Inf, then return +Inf.  */
 412       *result = *arg;
 413       result->sign = 0;
 414       return true;
 415
 416     case rvc_zero:
 417       /* Zero may set errno and/or raise an exception.  */
 418       return false;
 419
 420     case rvc_normal:
 421       /* For normal numbers, proceed iff radix == 2.  In GCC,
 422          normalized significands are in the range [0.5, 1.0).  We
 423          want the exponent as if they were [1.0, 2.0) so get the
 424          exponent and subtract 1.  */
 425       if (format->b == 2)
 426         {
 427           real_from_integer (result, format, REAL_EXP (arg) - 1, SIGNED);
 428           return true;
 429         }
 430       return false;
 431     }
 432 }
 433
 434 /* Try to evaluate:
 435
 436       *RESULT = significand (*ARG)
 437
 438    in format FORMAT.  Return true on success.  */
 439
 440 static bool
 441 fold_const_significand (real_value *result, const real_value *arg,
 442                         const real_format *format)
 443 {
 444   switch (arg->cl)
 445     {
 446     case rvc_zero:
 447     case rvc_nan:
 448     case rvc_inf:
 449       /* If arg is +-0, +-Inf or +-NaN, then return it.  */
 450       *result = *arg;
 451       return true;
 452
 453     case rvc_normal:
 454       /* For normal numbers, proceed iff radix == 2.  */
 455       if (format->b == 2)
 456         {
 457           *result = *arg;
 458           /* In GCC, normalized significands are in the range [0.5, 1.0).
 459              We want them to be [1.0, 2.0) so set the exponent to 1.  */
 460           SET_REAL_EXP (result, 1);
 461           return true;
 462         }
 463       return false;
 464     }
 465 }
 466
 467 /* Try to evaluate:
 468
 469       *RESULT = f (*ARG)
 470
 471    where FORMAT is the format of *ARG and PRECISION is the number of
 472    significant bits in the result.  Return true on success.  */
 473
 474 static bool
 475 fold_const_conversion (wide_int *result,
 476                        void (*fn) (real_value *, format_helper,
 477                                    const real_value *),
 478                        const real_value *arg, unsigned int precision,
 479                        const real_format *format)
 480 {
 481   if (!real_isfinite (arg))
 482     return false;
 483
 484   real_value rounded;
 485   fn (&rounded, format, arg);
 486
 487   bool fail = false;
 488   *result = real_to_integer (&rounded, &fail, precision);
 489   return !fail;
 490 }
 491
 492 /* Try to evaluate:
 493
 494       *RESULT = pow (*ARG0, *ARG1)
 495
 496    in format FORMAT.  Return true on success.  */
 497
 498 static bool
 499 fold_const_pow (real_value *result, const real_value *arg0,
 500                 const real_value *arg1, const real_format *format)
 501 {
 502   if (do_mpfr_arg2 (result, mpfr_pow, arg0, arg1, format))
 503     return true;
 504
 505   /* Check for an integer exponent.  */
 506   REAL_VALUE_TYPE cint1;
 507   HOST_WIDE_INT n1 = real_to_integer (arg1);
 508   real_from_integer (&cint1, VOIDmode, n1, SIGNED);
 509   /* Attempt to evaluate pow at compile-time, unless this should
 510      raise an exception.  */
 511   if (real_identical (arg1, &cint1)
 512       && (n1 > 0
 513           || (!flag_trapping_math && !flag_errno_math)
 514           || !real_equal (arg0, &dconst0)))
 515     {
 516       bool inexact = real_powi (result, format, arg0, n1);
 517       /* Avoid the folding if flag_signaling_nans is on.  */
 518       if (flag_unsafe_math_optimizations
 519           || (!inexact
 520               && !(flag_signaling_nans
 521                    && REAL_VALUE_ISSIGNALING_NAN (*arg0))))
 522         return true;
 523     }
 524
 525   return false;
 526 }
 527
 528 /* Try to evaluate:
 529
 530       *RESULT = nextafter (*ARG0, *ARG1)
 531
 532    or
 533
 534       *RESULT = nexttoward (*ARG0, *ARG1)
 535
 536    in format FORMAT.  Return true on success.  */
 537
 538 static bool
 539 fold_const_nextafter (real_value *result, const real_value *arg0,
 540                       const real_value *arg1, const real_format *format)
 541 {
 542   if (REAL_VALUE_ISSIGNALING_NAN (*arg0)
 543       || REAL_VALUE_ISSIGNALING_NAN (*arg1))
 544     return false;
 545
 546   /* Don't handle composite modes, nor decimal, nor modes without
 547      inf or denorm at least for now.  */
 548   if (format->pnan < format->p
 549       || format->b == 10
 550       || !format->has_inf
 551       || !format->has_denorm)
 552     return false;
 553
 554   if (real_nextafter (result, format, arg0, arg1)
 555       /* If raising underflow or overflow and setting errno to ERANGE,
 556          fail if we care about those side-effects.  */
 557       && (flag_trapping_math || flag_errno_math))
 558     return false;
 559   /* Similarly for nextafter (0, 1) raising underflow.  */
 560   else if (flag_trapping_math
 561            && arg0->cl == rvc_zero
 562            && result->cl != rvc_zero)
 563     return false;
 564
 565   real_convert (result, format, result);
 566
 567   return true;
 568 }
 569
 570 /* Try to evaluate:
 571
 572       *RESULT = ldexp (*ARG0, ARG1)
 573
 574    in format FORMAT.  Return true on success.  */
 575
 576 static bool
 577 fold_const_builtin_load_exponent (real_value *result, const real_value *arg0,
 578                                   const wide_int_ref &arg1,
 579                                   const real_format *format)
 580 {
 581   /* Bound the maximum adjustment to twice the range of the
 582      mode's valid exponents.  Use abs to ensure the range is
 583      positive as a sanity check.  */
 584   int max_exp_adj = 2 * labs (format->emax - format->emin);
 585
 586   /* The requested adjustment must be inside this range.  This
 587      is a preliminary cap to avoid things like overflow, we
 588      may still fail to compute the result for other reasons.  */
 589   if (wi::les_p (arg1, -max_exp_adj) || wi::ges_p (arg1, max_exp_adj))
 590     return false;
 591
 592   /* Don't perform operation if we honor signaling NaNs and
 593      operand is a signaling NaN.  */
 594   if (!flag_unsafe_math_optimizations
 595       && flag_signaling_nans
 596       && REAL_VALUE_ISSIGNALING_NAN (*arg0))
 597     return false;
 598
 599   REAL_VALUE_TYPE initial_result;
 600   real_ldexp (&initial_result, arg0, arg1.to_shwi ());
 601
 602   /* Ensure we didn't overflow.  */
 603   if (real_isinf (&initial_result))
 604     return false;
 605
 606   /* Only proceed if the target mode can hold the
 607      resulting value.  */
 608   *result = real_value_truncate (format, initial_result);
 609   return real_equal (&initial_result, result);
 610 }
 611
 612 /* Fold a call to __builtin_nan or __builtin_nans with argument ARG and
 613    return type TYPE.  QUIET is true if a quiet rather than signalling
 614    NaN is required.  */
 615
 616 static tree
 617 fold_const_builtin_nan (tree type, tree arg, bool quiet)
 618 {
 619   REAL_VALUE_TYPE real;
 620   const char *str = c_getstr (arg);
 621   if (str && real_nan (&real, str, quiet, TYPE_MODE (type)))
 622     return build_real (type, real);
 623   return NULL_TREE;
 624 }
 625
 626 /* Fold a call to IFN_REDUC_<CODE> (ARG), returning a value of type TYPE.  */
 627
 628 static tree
 629 fold_const_reduction (tree type, tree arg, tree_code code)
 630 {
 631   unsigned HOST_WIDE_INT nelts;
 632   if (TREE_CODE (arg) != VECTOR_CST
 633       || !VECTOR_CST_NELTS (arg).is_constant (&nelts))
 634     return NULL_TREE;
 635
 636   tree res = VECTOR_CST_ELT (arg, 0);
 637   for (unsigned HOST_WIDE_INT i = 1; i < nelts; i++)
 638     {
 639       res = const_binop (code, type, res, VECTOR_CST_ELT (arg, i));
 640       if (res == NULL_TREE || !CONSTANT_CLASS_P (res))
 641         return NULL_TREE;
 642     }
 643   return res;
 644 }
 645
 646 /* Fold a call to IFN_VEC_CONVERT (ARG) returning TYPE.  */
 647
 648 static tree
 649 fold_const_vec_convert (tree ret_type, tree arg)
 650 {
 651   enum tree_code code = NOP_EXPR;
 652   tree arg_type = TREE_TYPE (arg);
 653   if (TREE_CODE (arg) != VECTOR_CST)
 654     return NULL_TREE;
 655
 656   gcc_checking_assert (VECTOR_TYPE_P (ret_type) && VECTOR_TYPE_P (arg_type));
 657
 658   if (INTEGRAL_TYPE_P (TREE_TYPE (ret_type))
 659       && SCALAR_FLOAT_TYPE_P (TREE_TYPE (arg_type)))
 660     code = FIX_TRUNC_EXPR;
 661   else if (INTEGRAL_TYPE_P (TREE_TYPE (arg_type))
 662            && SCALAR_FLOAT_TYPE_P (TREE_TYPE (ret_type)))
 663     code = FLOAT_EXPR;
 664
 665   /* We can't handle steps directly when extending, since the
 666      values need to wrap at the original precision first.  */
 667   bool step_ok_p
 668     = (INTEGRAL_TYPE_P (TREE_TYPE (ret_type))
 669        && INTEGRAL_TYPE_P (TREE_TYPE (arg_type))
 670        && (TYPE_PRECISION (TREE_TYPE (ret_type))
 671            <= TYPE_PRECISION (TREE_TYPE (arg_type))));
 672   tree_vector_builder elts;
 673   if (!elts.new_unary_operation (ret_type, arg, step_ok_p))
 674     return NULL_TREE;
 675
 676   unsigned int count = elts.encoded_nelts ();
 677   for (unsigned int i = 0; i < count; ++i)
 678     {
 679       tree elt = fold_unary (code, TREE_TYPE (ret_type),
 680                              VECTOR_CST_ELT (arg, i));
 681       if (elt == NULL_TREE || !CONSTANT_CLASS_P (elt))
 682         return NULL_TREE;
 683       elts.quick_push (elt);
 684     }
 685
 686   return elts.build ();
 687 }
 688
 689 /* Try to evaluate:
 690
 691       IFN_WHILE_ULT (ARG0, ARG1, (TYPE) { ... })
 692
 693    Return the value on success and null on failure.  */
 694
 695 static tree
 696 fold_while_ult (tree type, poly_uint64 arg0, poly_uint64 arg1)
 697 {
 698   if (known_ge (arg0, arg1))
 699     return build_zero_cst (type);
 700
 701   if (maybe_ge (arg0, arg1))
 702     return NULL_TREE;
 703
 704   poly_uint64 diff = arg1 - arg0;
 705   poly_uint64 nelts = TYPE_VECTOR_SUBPARTS (type);
 706   if (known_ge (diff, nelts))
 707     return build_all_ones_cst (type);
 708
 709   unsigned HOST_WIDE_INT const_diff;
 710   if (known_le (diff, nelts) && diff.is_constant (&const_diff))
 711     {
 712       tree minus_one = build_minus_one_cst (TREE_TYPE (type));
 713       tree zero = build_zero_cst (TREE_TYPE (type));
 714       return build_vector_a_then_b (type, const_diff, minus_one, zero);
 715     }
 716   return NULL_TREE;
 717 }
 718
 719 /* Try to evaluate:
 720
 721       *RESULT = FN (*ARG)
 722
 723    in format FORMAT.  Return true on success.  */
 724
 725 static bool
 726 fold_const_call_ss (real_value *result, combined_fn fn,
 727                     const real_value *arg, const real_format *format)
 728 {
 729   switch (fn)
 730     {
 731     CASE_CFN_SQRT:
 732     CASE_CFN_SQRT_FN:
 733       return (real_compare (GE_EXPR, arg, &dconst0)
 734               && do_mpfr_arg1 (result, mpfr_sqrt, arg, format));
 735
 736     CASE_CFN_CBRT:
 737       return do_mpfr_arg1 (result, mpfr_cbrt, arg, format);
 738
 739     CASE_CFN_ASIN:
 740       return (real_compare (GE_EXPR, arg, &dconstm1)
 741               && real_compare (LE_EXPR, arg, &dconst1)
 742               && do_mpfr_arg1 (result, mpfr_asin, arg, format));
 743
 744     CASE_CFN_ACOS:
 745       return (real_compare (GE_EXPR, arg, &dconstm1)
 746               && real_compare (LE_EXPR, arg, &dconst1)
 747               && do_mpfr_arg1 (result, mpfr_acos, arg, format));
 748
 749     CASE_CFN_ATAN:
 750       return do_mpfr_arg1 (result, mpfr_atan, arg, format);
 751
 752     CASE_CFN_ASINH:
 753       return do_mpfr_arg1 (result, mpfr_asinh, arg, format);
 754
 755     CASE_CFN_ACOSH:
 756       return (real_compare (GE_EXPR, arg, &dconst1)
 757               && do_mpfr_arg1 (result, mpfr_acosh, arg, format));
 758
 759     CASE_CFN_ATANH:
 760       return (real_compare (GE_EXPR, arg, &dconstm1)
 761               && real_compare (LE_EXPR, arg, &dconst1)
 762               && do_mpfr_arg1 (result, mpfr_atanh, arg, format));
 763
 764     CASE_CFN_SIN:
 765       return do_mpfr_arg1 (result, mpfr_sin, arg, format);
 766
 767     CASE_CFN_COS:
 768       return do_mpfr_arg1 (result, mpfr_cos, arg, format);
 769
 770     CASE_CFN_TAN:
 771       return do_mpfr_arg1 (result, mpfr_tan, arg, format);
 772
 773     CASE_CFN_SINH:
 774       return do_mpfr_arg1 (result, mpfr_sinh, arg, format);
 775
 776     CASE_CFN_COSH:
 777       return do_mpfr_arg1 (result, mpfr_cosh, arg, format);
 778
 779     CASE_CFN_TANH:
 780       return do_mpfr_arg1 (result, mpfr_tanh, arg, format);
 781
 782     CASE_CFN_ERF:
 783       return do_mpfr_arg1 (result, mpfr_erf, arg, format);
 784
 785     CASE_CFN_ERFC:
 786       return do_mpfr_arg1 (result, mpfr_erfc, arg, format);
 787
 788     CASE_CFN_TGAMMA:
 789       return do_mpfr_arg1 (result, mpfr_gamma, arg, format);
 790
 791     CASE_CFN_EXP:
 792       return do_mpfr_arg1 (result, mpfr_exp, arg, format);
 793
 794     CASE_CFN_EXP2:
 795       return do_mpfr_arg1 (result, mpfr_exp2, arg, format);
 796
 797     CASE_CFN_EXP10:
 798     CASE_CFN_POW10:
 799       return do_mpfr_arg1 (result, mpfr_exp10, arg, format);
 800
 801     CASE_CFN_EXPM1:
 802       return do_mpfr_arg1 (result, mpfr_expm1, arg, format);
 803
 804     CASE_CFN_LOG:
 805       return (real_compare (GT_EXPR, arg, &dconst0)
 806               && do_mpfr_arg1 (result, mpfr_log, arg, format));
 807
 808     CASE_CFN_LOG2:
 809       return (real_compare (GT_EXPR, arg, &dconst0)
 810               && do_mpfr_arg1 (result, mpfr_log2, arg, format));
 811
 812     CASE_CFN_LOG10:
 813       return (real_compare (GT_EXPR, arg, &dconst0)
 814               && do_mpfr_arg1 (result, mpfr_log10, arg, format));
 815
 816     CASE_CFN_LOG1P:
 817       return (real_compare (GT_EXPR, arg, &dconstm1)
 818               && do_mpfr_arg1 (result, mpfr_log1p, arg, format));
 819
 820     CASE_CFN_J0:
 821       return do_mpfr_arg1 (result, mpfr_j0, arg, format);
 822
 823     CASE_CFN_J1:
 824       return do_mpfr_arg1 (result, mpfr_j1, arg, format);
 825
 826     CASE_CFN_Y0:
 827       return (real_compare (GT_EXPR, arg, &dconst0)
 828               && do_mpfr_arg1 (result, mpfr_y0, arg, format));
 829
 830     CASE_CFN_Y1:
 831       return (real_compare (GT_EXPR, arg, &dconst0)
 832               && do_mpfr_arg1 (result, mpfr_y1, arg, format));
 833
 834     CASE_CFN_FLOOR:
 835     CASE_CFN_FLOOR_FN:
 836       if (!REAL_VALUE_ISSIGNALING_NAN (*arg))
 837         {
 838           real_floor (result, format, arg);
 839           return true;
 840         }
 841       return false;
 842
 843     CASE_CFN_CEIL:
 844     CASE_CFN_CEIL_FN:
 845       if (!REAL_VALUE_ISSIGNALING_NAN (*arg))
 846         {
 847           real_ceil (result, format, arg);
 848           return true;
 849         }
 850       return false;
 851
 852     CASE_CFN_TRUNC:
 853     CASE_CFN_TRUNC_FN:
 854       if (!REAL_VALUE_ISSIGNALING_NAN (*arg))
 855         {
 856           real_trunc (result, format, arg);
 857           return true;
 858         }
 859       return false;
 860
 861     CASE_CFN_ROUND:
 862     CASE_CFN_ROUND_FN:
 863       if (!REAL_VALUE_ISSIGNALING_NAN (*arg))
 864         {
 865           real_round (result, format, arg);
 866           return true;
 867         }
 868       return false;
 869
 870     CASE_CFN_ROUNDEVEN:
 871     CASE_CFN_ROUNDEVEN_FN:
 872       if (!REAL_VALUE_ISSIGNALING_NAN (*arg))
 873         {
 874           real_roundeven (result, format, arg);
 875           return true;
 876         }
 877       return false;
 878
 879     CASE_CFN_LOGB:
 880       return fold_const_logb (result, arg, format);
 881
 882     CASE_CFN_SIGNIFICAND:
 883       return fold_const_significand (result, arg, format);
 884
 885     default:
 886       return false;
 887     }
 888 }
 889
 890 /* Try to evaluate:
 891
 892       *RESULT = FN (*ARG)
 893
 894    where FORMAT is the format of ARG and PRECISION is the number of
 895    significant bits in the result.  Return true on success.  */
 896
 897 static bool
 898 fold_const_call_ss (wide_int *result, combined_fn fn,
 899                     const real_value *arg, unsigned int precision,
 900                     const real_format *format)
 901 {
 902   switch (fn)
 903     {
 904     CASE_CFN_SIGNBIT:
 905       if (real_isneg (arg))
 906         *result = wi::one (precision);
 907       else
 908         *result = wi::zero (precision);
 909       return true;
 910
 911     CASE_CFN_ILOGB:
 912       /* For ilogb we don't know FP_ILOGB0, so only handle normal values.
 913          Proceed iff radix == 2.  In GCC, normalized significands are in
 914          the range [0.5, 1.0).  We want the exponent as if they were
 915          [1.0, 2.0) so get the exponent and subtract 1.  */
 916       if (arg->cl == rvc_normal && format->b == 2)
 917         {
 918           *result = wi::shwi (REAL_EXP (arg) - 1, precision);
 919           return true;
 920         }
 921       return false;
 922
 923     CASE_CFN_ICEIL:
 924     CASE_CFN_LCEIL:
 925     CASE_CFN_LLCEIL:
 926       return fold_const_conversion (result, real_ceil, arg,
 927                                     precision, format);
 928
 929     CASE_CFN_LFLOOR:
 930     CASE_CFN_IFLOOR:
 931     CASE_CFN_LLFLOOR:
 932       return fold_const_conversion (result, real_floor, arg,
 933                                     precision, format);
 934
 935     CASE_CFN_IROUND:
 936     CASE_CFN_LROUND:
 937     CASE_CFN_LLROUND:
 938       return fold_const_conversion (result, real_round, arg,
 939                                     precision, format);
 940
 941     CASE_CFN_IRINT:
 942     CASE_CFN_LRINT:
 943     CASE_CFN_LLRINT:
 944       /* Not yet folded to a constant.  */
 945       return false;
 946
 947     CASE_CFN_FINITE:
 948     case CFN_BUILT_IN_FINITED32:
 949     case CFN_BUILT_IN_FINITED64:
 950     case CFN_BUILT_IN_FINITED128:
 951     case CFN_BUILT_IN_ISFINITE:
 952       *result = wi::shwi (real_isfinite (arg) ? 1 : 0, precision);
 953       return true;
 954
 955     CASE_CFN_ISINF:
 956     case CFN_BUILT_IN_ISINFD32:
 957     case CFN_BUILT_IN_ISINFD64:
 958     case CFN_BUILT_IN_ISINFD128:
 959       if (real_isinf (arg))
 960         *result = wi::shwi (arg->sign ? -1 : 1, precision);
 961       else
 962         *result = wi::shwi (0, precision);
 963       return true;
 964
 965     CASE_CFN_ISNAN:
 966     case CFN_BUILT_IN_ISNAND32:
 967     case CFN_BUILT_IN_ISNAND64:
 968     case CFN_BUILT_IN_ISNAND128:
 969       *result = wi::shwi (real_isnan (arg) ? 1 : 0, precision);
 970       return true;
 971
 972     default:
 973       return false;
 974     }
 975 }
 976
 977 /* Try to evaluate:
 978
 979       *RESULT = FN (ARG)
 980
 981    where ARG_TYPE is the type of ARG and PRECISION is the number of bits
 982    in the result.  Return true on success.  */
 983
 984 static bool
 985 fold_const_call_ss (wide_int *result, combined_fn fn, const wide_int_ref &arg,
 986                     unsigned int precision, tree arg_type)
 987 {
 988   switch (fn)
 989     {
 990     CASE_CFN_FFS:
 991       *result = wi::shwi (wi::ffs (arg), precision);
 992       return true;
 993
 994     CASE_CFN_CLZ:
 995       {
 996         int tmp;
 997         if (wi::ne_p (arg, 0))
 998           tmp = wi::clz (arg);
 999         else if (!CLZ_DEFINED_VALUE_AT_ZERO (SCALAR_INT_TYPE_MODE (arg_type),
1000                                              tmp))
1001           tmp = TYPE_PRECISION (arg_type);
1002         *result = wi::shwi (tmp, precision);
1003         return true;
1004       }
1005
1006     CASE_CFN_CTZ:
1007       {
1008         int tmp;
1009         if (wi::ne_p (arg, 0))
1010           tmp = wi::ctz (arg);
1011         else if (!CTZ_DEFINED_VALUE_AT_ZERO (SCALAR_INT_TYPE_MODE (arg_type),
1012                                              tmp))
1013           tmp = TYPE_PRECISION (arg_type);
1014         *result = wi::shwi (tmp, precision);
1015         return true;
1016       }
1017
1018     CASE_CFN_CLRSB:
1019       *result = wi::shwi (wi::clrsb (arg), precision);
1020       return true;
1021
1022     CASE_CFN_POPCOUNT:
1023       *result = wi::shwi (wi::popcount (arg), precision);
1024       return true;
1025
1026     CASE_CFN_PARITY:
1027       *result = wi::shwi (wi::parity (arg), precision);
1028       return true;
1029
1030     case CFN_BUILT_IN_BSWAP16:
1031     case CFN_BUILT_IN_BSWAP32:
1032     case CFN_BUILT_IN_BSWAP64:
1033     case CFN_BUILT_IN_BSWAP128:
1034       *result = wide_int::from (arg, precision, TYPE_SIGN (arg_type)).bswap ();
1035       return true;
1036
1037     default:
1038       return false;
1039     }
1040 }
1041
1042 /* Try to evaluate:
1043
1044       RESULT = FN (*ARG)
1045
1046    where FORMAT is the format of ARG and of the real and imaginary parts
1047    of RESULT, passed as RESULT_REAL and RESULT_IMAG respectively.  Return
1048    true on success.  */
1049
1050 static bool
1051 fold_const_call_cs (real_value *result_real, real_value *result_imag,
1052                     combined_fn fn, const real_value *arg,
1053                     const real_format *format)
1054 {
1055   switch (fn)
1056     {
1057     CASE_CFN_CEXPI:
1058       /* cexpi(x+yi) = cos(x)+sin(y)*i.  */
1059       return do_mpfr_sincos (result_imag, result_real, arg, format);
1060
1061     default:
1062       return false;
1063     }
1064 }
1065
1066 /* Try to evaluate:
1067
1068       *RESULT = fn (ARG)
1069
1070    where FORMAT is the format of RESULT and of the real and imaginary parts
1071    of ARG, passed as ARG_REAL and ARG_IMAG respectively.  Return true on
1072    success.  */
1073
1074 static bool
1075 fold_const_call_sc (real_value *result, combined_fn fn,
1076                     const real_value *arg_real, const real_value *arg_imag,
1077                     const real_format *format)
1078 {
1079   switch (fn)
1080     {
1081     CASE_CFN_CABS:
1082       return do_mpfr_arg2 (result, mpfr_hypot, arg_real, arg_imag, format);
1083
1084     default:
1085       return false;
1086     }
1087 }
1088
1089 /* Try to evaluate:
1090
1091       RESULT = fn (ARG)
1092
1093    where FORMAT is the format of the real and imaginary parts of RESULT
1094    (RESULT_REAL and RESULT_IMAG) and of ARG (ARG_REAL and ARG_IMAG).
1095    Return true on success.  */
1096
1097 static bool
1098 fold_const_call_cc (real_value *result_real, real_value *result_imag,
1099                     combined_fn fn, const real_value *arg_real,
1100                     const real_value *arg_imag, const real_format *format)
1101 {
1102   switch (fn)
1103     {
1104     CASE_CFN_CCOS:
1105       return do_mpc_arg1 (result_real, result_imag, mpc_cos,
1106                           arg_real, arg_imag, format);
1107
1108     CASE_CFN_CCOSH:
1109       return do_mpc_arg1 (result_real, result_imag, mpc_cosh,
1110                           arg_real, arg_imag, format);
1111
1112     CASE_CFN_CPROJ:
1113       if (real_isinf (arg_real) || real_isinf (arg_imag))
1114         {
1115           real_inf (result_real);
1116           *result_imag = dconst0;
1117           result_imag->sign = arg_imag->sign;
1118         }
1119       else
1120         {
1121           *result_real = *arg_real;
1122           *result_imag = *arg_imag;
1123         }
1124       return true;
1125
1126     CASE_CFN_CSIN:
1127       return do_mpc_arg1 (result_real, result_imag, mpc_sin,
1128                           arg_real, arg_imag, format);
1129
1130     CASE_CFN_CSINH:
1131       return do_mpc_arg1 (result_real, result_imag, mpc_sinh,
1132                           arg_real, arg_imag, format);
1133
1134     CASE_CFN_CTAN:
1135       return do_mpc_arg1 (result_real, result_imag, mpc_tan,
1136                           arg_real, arg_imag, format);
1137
1138     CASE_CFN_CTANH:
1139       return do_mpc_arg1 (result_real, result_imag, mpc_tanh,
1140                           arg_real, arg_imag, format);
1141
1142     CASE_CFN_CLOG:
1143       return do_mpc_arg1 (result_real, result_imag, mpc_log,
1144                           arg_real, arg_imag, format);
1145
1146     CASE_CFN_CSQRT:
1147       return do_mpc_arg1 (result_real, result_imag, mpc_sqrt,
1148                           arg_real, arg_imag, format);
1149
1150     CASE_CFN_CASIN:
1151       return do_mpc_arg1 (result_real, result_imag, mpc_asin,
1152                           arg_real, arg_imag, format);
1153
1154     CASE_CFN_CACOS:
1155       return do_mpc_arg1 (result_real, result_imag, mpc_acos,
1156                           arg_real, arg_imag, format);
1157
1158     CASE_CFN_CATAN:
1159       return do_mpc_arg1 (result_real, result_imag, mpc_atan,
1160                           arg_real, arg_imag, format);
1161
1162     CASE_CFN_CASINH:
1163       return do_mpc_arg1 (result_real, result_imag, mpc_asinh,
1164                           arg_real, arg_imag, format);
1165
1166     CASE_CFN_CACOSH:
1167       return do_mpc_arg1 (result_real, result_imag, mpc_acosh,
1168                           arg_real, arg_imag, format);
1169
1170     CASE_CFN_CATANH:
1171       return do_mpc_arg1 (result_real, result_imag, mpc_atanh,
1172                           arg_real, arg_imag, format);
1173
1174     CASE_CFN_CEXP:
1175       return do_mpc_arg1 (result_real, result_imag, mpc_exp,
1176                           arg_real, arg_imag, format);
1177
1178     default:
1179       return false;
1180     }
1181 }
1182
1183 /* Subroutine of fold_const_call, with the same interface.  Handle cases
1184    where the arguments and result are numerical.  */
1185
1186 static tree
1187 fold_const_call_1 (combined_fn fn, tree type, tree arg)
1188 {
1189   machine_mode mode = TYPE_MODE (type);
1190   machine_mode arg_mode = TYPE_MODE (TREE_TYPE (arg));
1191
1192   if (integer_cst_p (arg))
1193     {
1194       if (SCALAR_INT_MODE_P (mode))
1195         {
1196           wide_int result;
1197           if (fold_const_call_ss (&result, fn, wi::to_wide (arg),
1198                                   TYPE_PRECISION (type), TREE_TYPE (arg)))
1199             return wide_int_to_tree (type, result);
1200         }
1201       return NULL_TREE;
1202     }
1203
1204   if (real_cst_p (arg))
1205     {
1206       gcc_checking_assert (SCALAR_FLOAT_MODE_P (arg_mode));
1207       if (mode == arg_mode)
1208         {
1209           /* real -> real.  */
1210           REAL_VALUE_TYPE result;
1211           if (fold_const_call_ss (&result, fn, TREE_REAL_CST_PTR (arg),
1212                                   REAL_MODE_FORMAT (mode)))
1213             return build_real (type, result);
1214         }
1215       else if (COMPLEX_MODE_P (mode)
1216                && GET_MODE_INNER (mode) == arg_mode)
1217         {
1218           /* real -> complex real.  */
1219           REAL_VALUE_TYPE result_real, result_imag;
1220           if (fold_const_call_cs (&result_real, &result_imag, fn,
1221                                   TREE_REAL_CST_PTR (arg),
1222                                   REAL_MODE_FORMAT (arg_mode)))
1223             return build_complex (type,
1224                                   build_real (TREE_TYPE (type), result_real),
1225                                   build_real (TREE_TYPE (type), result_imag));
1226         }
1227       else if (INTEGRAL_TYPE_P (type))
1228         {
1229           /* real -> int.  */
1230           wide_int result;
1231           if (fold_const_call_ss (&result, fn,
1232                                   TREE_REAL_CST_PTR (arg),
1233                                   TYPE_PRECISION (type),
1234                                   REAL_MODE_FORMAT (arg_mode)))
1235             return wide_int_to_tree (type, result);
1236         }
1237       return NULL_TREE;
1238     }
1239
1240   if (complex_cst_p (arg))
1241     {
1242       gcc_checking_assert (COMPLEX_MODE_P (arg_mode));
1243       machine_mode inner_mode = GET_MODE_INNER (arg_mode);
1244       tree argr = TREE_REALPART (arg);
1245       tree argi = TREE_IMAGPART (arg);
1246       if (mode == arg_mode
1247           && real_cst_p (argr)
1248           && real_cst_p (argi))
1249         {
1250           /* complex real -> complex real.  */
1251           REAL_VALUE_TYPE result_real, result_imag;
1252           if (fold_const_call_cc (&result_real, &result_imag, fn,
1253                                   TREE_REAL_CST_PTR (argr),
1254                                   TREE_REAL_CST_PTR (argi),
1255                                   REAL_MODE_FORMAT (inner_mode)))
1256             return build_complex (type,
1257                                   build_real (TREE_TYPE (type), result_real),
1258                                   build_real (TREE_TYPE (type), result_imag));
1259         }
1260       if (mode == inner_mode
1261           && real_cst_p (argr)
1262           && real_cst_p (argi))
1263         {
1264           /* complex real -> real.  */
1265           REAL_VALUE_TYPE result;
1266           if (fold_const_call_sc (&result, fn,
1267                                   TREE_REAL_CST_PTR (argr),
1268                                   TREE_REAL_CST_PTR (argi),
1269                                   REAL_MODE_FORMAT (inner_mode)))
1270             return build_real (type, result);
1271         }
1272       return NULL_TREE;
1273     }
1274
1275   return NULL_TREE;
1276 }
1277
1278 /* Try to fold FN (ARG) to a constant.  Return the constant on success,
1279    otherwise return null.  TYPE is the type of the return value.  */
1280
1281 tree
1282 fold_const_call (combined_fn fn, tree type, tree arg)
1283 {
1284   switch (fn)
1285     {
1286     case CFN_BUILT_IN_STRLEN:
1287       if (const char *str = c_getstr (arg))
1288         return build_int_cst (type, strlen (str));
1289       return NULL_TREE;
1290
1291     CASE_CFN_NAN:
1292     CASE_FLT_FN_FLOATN_NX (CFN_BUILT_IN_NAN):
1293     case CFN_BUILT_IN_NAND32:
1294     case CFN_BUILT_IN_NAND64:
1295     case CFN_BUILT_IN_NAND128:
1296       return fold_const_builtin_nan (type, arg, true);
1297
1298     CASE_CFN_NANS:
1299     CASE_FLT_FN_FLOATN_NX (CFN_BUILT_IN_NANS):
1300     case CFN_BUILT_IN_NANSD32:
1301     case CFN_BUILT_IN_NANSD64:
1302     case CFN_BUILT_IN_NANSD128:
1303       return fold_const_builtin_nan (type, arg, false);
1304
1305     case CFN_REDUC_PLUS:
1306       return fold_const_reduction (type, arg, PLUS_EXPR);
1307
1308     case CFN_REDUC_MAX:
1309       return fold_const_reduction (type, arg, MAX_EXPR);
1310
1311     case CFN_REDUC_MIN:
1312       return fold_const_reduction (type, arg, MIN_EXPR);
1313
1314     case CFN_REDUC_AND:
1315       return fold_const_reduction (type, arg, BIT_AND_EXPR);
1316
1317     case CFN_REDUC_IOR:
1318       return fold_const_reduction (type, arg, BIT_IOR_EXPR);
1319
1320     case CFN_REDUC_XOR:
1321       return fold_const_reduction (type, arg, BIT_XOR_EXPR);
1322
1323     case CFN_VEC_CONVERT:
1324       return fold_const_vec_convert (type, arg);
1325
1326     default:
1327       return fold_const_call_1 (fn, type, arg);
1328     }
1329 }
1330
1331 /* Fold a call to IFN_FOLD_LEFT_<CODE> (ARG0, ARG1), returning a value
1332    of type TYPE.  */
1333
1334 static tree
1335 fold_const_fold_left (tree type, tree arg0, tree arg1, tree_code code)
1336 {
1337   if (TREE_CODE (arg1) != VECTOR_CST)
1338     return NULL_TREE;
1339
1340   unsigned HOST_WIDE_INT nelts;
1341   if (!VECTOR_CST_NELTS (arg1).is_constant (&nelts))
1342     return NULL_TREE;
1343
1344   for (unsigned HOST_WIDE_INT i = 0; i < nelts; i++)
1345     {
1346       arg0 = const_binop (code, type, arg0, VECTOR_CST_ELT (arg1, i));
1347       if (arg0 == NULL_TREE || !CONSTANT_CLASS_P (arg0))
1348         return NULL_TREE;
1349     }
1350   return arg0;
1351 }
1352
1353 /* Try to evaluate:
1354
1355       *RESULT = FN (*ARG0, *ARG1)
1356
1357    in format FORMAT.  Return true on success.  */
1358
1359 static bool
1360 fold_const_call_sss (real_value *result, combined_fn fn,
1361                      const real_value *arg0, const real_value *arg1,
1362                      const real_format *format)
1363 {
1364   switch (fn)
1365     {
1366     CASE_CFN_DREM:
1367     CASE_CFN_REMAINDER:
1368       return do_mpfr_arg2 (result, mpfr_remainder, arg0, arg1, format);
1369
1370     CASE_CFN_ATAN2:
1371       return do_mpfr_arg2 (result, mpfr_atan2, arg0, arg1, format);
1372
1373     CASE_CFN_FDIM:
1374       return do_mpfr_arg2 (result, mpfr_dim, arg0, arg1, format);
1375
1376     CASE_CFN_FMOD:
1377       return do_mpfr_arg2 (result, mpfr_fmod, arg0, arg1, format);
1378
1379     CASE_CFN_HYPOT:
1380       return do_mpfr_arg2 (result, mpfr_hypot, arg0, arg1, format);
1381
1382     CASE_CFN_COPYSIGN:
1383     CASE_CFN_COPYSIGN_FN:
1384       *result = *arg0;
1385       real_copysign (result, arg1);
1386       return true;
1387
1388     CASE_CFN_FMIN:
1389     CASE_CFN_FMIN_FN:
1390       return do_mpfr_arg2 (result, mpfr_min, arg0, arg1, format);
1391
1392     CASE_CFN_FMAX:
1393     CASE_CFN_FMAX_FN:
1394       return do_mpfr_arg2 (result, mpfr_max, arg0, arg1, format);
1395
1396     CASE_CFN_POW:
1397       return fold_const_pow (result, arg0, arg1, format);
1398
1399     CASE_CFN_NEXTAFTER:
1400     CASE_CFN_NEXTTOWARD:
1401       return fold_const_nextafter (result, arg0, arg1, format);
1402
1403     default:
1404       return false;
1405     }
1406 }
1407
1408 /* Try to evaluate:
1409
1410       *RESULT = FN (*ARG0, ARG1)
1411
1412    where FORMAT is the format of *RESULT and *ARG0.  Return true on
1413    success.  */
1414
1415 static bool
1416 fold_const_call_sss (real_value *result, combined_fn fn,
1417                      const real_value *arg0, const wide_int_ref &arg1,
1418                      const real_format *format)
1419 {
1420   switch (fn)
1421     {
1422     CASE_CFN_LDEXP:
1423       return fold_const_builtin_load_exponent (result, arg0, arg1, format);
1424
1425     CASE_CFN_SCALBN:
1426     CASE_CFN_SCALBLN:
1427       return (format->b == 2
1428               && fold_const_builtin_load_exponent (result, arg0, arg1,
1429                                                    format));
1430
1431     CASE_CFN_POWI:
1432       /* Avoid the folding if flag_signaling_nans is on and
1433          operand is a signaling NaN.  */
1434       if (!flag_unsafe_math_optimizations
1435           && flag_signaling_nans
1436           && REAL_VALUE_ISSIGNALING_NAN (*arg0))
1437         return false;
1438
1439       real_powi (result, format, arg0, arg1.to_shwi ());
1440       return true;
1441
1442     default:
1443       return false;
1444     }
1445 }
1446
1447 /* Try to evaluate:
1448
1449       *RESULT = FN (ARG0, *ARG1)
1450
1451    where FORMAT is the format of *RESULT and *ARG1.  Return true on
1452    success.  */
1453
1454 static bool
1455 fold_const_call_sss (real_value *result, combined_fn fn,
1456                      const wide_int_ref &arg0, const real_value *arg1,
1457                      const real_format *format)
1458 {
1459   switch (fn)
1460     {
1461     CASE_CFN_JN:
1462       return do_mpfr_arg2 (result, mpfr_jn, arg0, arg1, format);
1463
1464     CASE_CFN_YN:
1465       return (real_compare (GT_EXPR, arg1, &dconst0)
1466               && do_mpfr_arg2 (result, mpfr_yn, arg0, arg1, format));
1467
1468     default:
1469       return false;
1470     }
1471 }
1472
1473 /* Try to evaluate:
1474
1475       RESULT = fn (ARG0, ARG1)
1476
1477    where FORMAT is the format of the real and imaginary parts of RESULT
1478    (RESULT_REAL and RESULT_IMAG), of ARG0 (ARG0_REAL and ARG0_IMAG)
1479    and of ARG1 (ARG1_REAL and ARG1_IMAG).  Return true on success.  */
1480
1481 static bool
1482 fold_const_call_ccc (real_value *result_real, real_value *result_imag,
1483                      combined_fn fn, const real_value *arg0_real,
1484                      const real_value *arg0_imag, const real_value *arg1_real,
1485                      const real_value *arg1_imag, const real_format *format)
1486 {
1487   switch (fn)
1488     {
1489     CASE_CFN_CPOW:
1490       return do_mpc_arg2 (result_real, result_imag, mpc_pow,
1491                           arg0_real, arg0_imag, arg1_real, arg1_imag, format);
1492
1493     default:
1494       return false;
1495     }
1496 }
1497
1498 /* Subroutine of fold_const_call, with the same interface.  Handle cases
1499    where the arguments and result are numerical.  */
1500
1501 static tree
1502 fold_const_call_1 (combined_fn fn, tree type, tree arg0, tree arg1)
1503 {
1504   machine_mode mode = TYPE_MODE (type);
1505   machine_mode arg0_mode = TYPE_MODE (TREE_TYPE (arg0));
1506   machine_mode arg1_mode = TYPE_MODE (TREE_TYPE (arg1));
1507
1508   if (mode == arg0_mode
1509       && real_cst_p (arg0)
1510       && real_cst_p (arg1))
1511     {
1512       gcc_checking_assert (SCALAR_FLOAT_MODE_P (arg0_mode));
1513       REAL_VALUE_TYPE result;
1514       if (arg0_mode == arg1_mode)
1515         {
1516           /* real, real -> real.  */
1517           if (fold_const_call_sss (&result, fn, TREE_REAL_CST_PTR (arg0),
1518                                    TREE_REAL_CST_PTR (arg1),
1519                                    REAL_MODE_FORMAT (mode)))
1520             return build_real (type, result);
1521         }
1522       else if (arg1_mode == TYPE_MODE (long_double_type_node))
1523         switch (fn)
1524           {
1525           CASE_CFN_NEXTTOWARD:
1526             /* real, long double -> real.  */
1527             if (fold_const_call_sss (&result, fn, TREE_REAL_CST_PTR (arg0),
1528                                      TREE_REAL_CST_PTR (arg1),
1529                                      REAL_MODE_FORMAT (mode)))
1530               return build_real (type, result);
1531             break;
1532           default:
1533             break;
1534           }
1535       return NULL_TREE;
1536     }
1537
1538   if (real_cst_p (arg0)
1539       && integer_cst_p (arg1))
1540     {
1541       gcc_checking_assert (SCALAR_FLOAT_MODE_P (arg0_mode));
1542       if (mode == arg0_mode)
1543         {
1544           /* real, int -> real.  */
1545           REAL_VALUE_TYPE result;
1546           if (fold_const_call_sss (&result, fn, TREE_REAL_CST_PTR (arg0),
1547                                    wi::to_wide (arg1),
1548                                    REAL_MODE_FORMAT (mode)))
1549             return build_real (type, result);
1550         }
1551       return NULL_TREE;
1552     }
1553
1554   if (integer_cst_p (arg0)
1555       && real_cst_p (arg1))
1556     {
1557       gcc_checking_assert (SCALAR_FLOAT_MODE_P (arg1_mode));
1558       if (mode == arg1_mode)
1559         {
1560           /* int, real -> real.  */
1561           REAL_VALUE_TYPE result;
1562           if (fold_const_call_sss (&result, fn, wi::to_wide (arg0),
1563                                    TREE_REAL_CST_PTR (arg1),
1564                                    REAL_MODE_FORMAT (mode)))
1565             return build_real (type, result);
1566         }
1567       return NULL_TREE;
1568     }
1569
1570   if (arg0_mode == arg1_mode
1571       && complex_cst_p (arg0)
1572       && complex_cst_p (arg1))
1573     {
1574       gcc_checking_assert (COMPLEX_MODE_P (arg0_mode));
1575       machine_mode inner_mode = GET_MODE_INNER (arg0_mode);
1576       tree arg0r = TREE_REALPART (arg0);
1577       tree arg0i = TREE_IMAGPART (arg0);
1578       tree arg1r = TREE_REALPART (arg1);
1579       tree arg1i = TREE_IMAGPART (arg1);
1580       if (mode == arg0_mode
1581           && real_cst_p (arg0r)
1582           && real_cst_p (arg0i)
1583           && real_cst_p (arg1r)
1584           && real_cst_p (arg1i))
1585         {
1586           /* complex real, complex real -> complex real.  */
1587           REAL_VALUE_TYPE result_real, result_imag;
1588           if (fold_const_call_ccc (&result_real, &result_imag, fn,
1589                                    TREE_REAL_CST_PTR (arg0r),
1590                                    TREE_REAL_CST_PTR (arg0i),
1591                                    TREE_REAL_CST_PTR (arg1r),
1592                                    TREE_REAL_CST_PTR (arg1i),
1593                                    REAL_MODE_FORMAT (inner_mode)))
1594             return build_complex (type,
1595                                   build_real (TREE_TYPE (type), result_real),
1596                                   build_real (TREE_TYPE (type), result_imag));
1597         }
1598       return NULL_TREE;
1599     }
1600
1601   return NULL_TREE;
1602 }
1603
1604 /* Try to fold FN (ARG0, ARG1) to a constant.  Return the constant on success,
1605    otherwise return null.  TYPE is the type of the return value.  */
1606
1607 tree
1608 fold_const_call (combined_fn fn, tree type, tree arg0, tree arg1)
1609 {
1610   const char *p0, *p1;
1611   char c;
1612   switch (fn)
1613     {
1614     case CFN_BUILT_IN_STRSPN:
1615       if ((p0 = c_getstr (arg0)) && (p1 = c_getstr (arg1)))
1616         return build_int_cst (type, strspn (p0, p1));
1617       return NULL_TREE;
1618
1619     case CFN_BUILT_IN_STRCSPN:
1620       if ((p0 = c_getstr (arg0)) && (p1 = c_getstr (arg1)))
1621         return build_int_cst (type, strcspn (p0, p1));
1622       return NULL_TREE;
1623
1624     case CFN_BUILT_IN_STRCMP:
1625       if ((p0 = c_getstr (arg0)) && (p1 = c_getstr (arg1)))
1626         return build_cmp_result (type, strcmp (p0, p1));
1627       return NULL_TREE;
1628
1629     case CFN_BUILT_IN_STRCASECMP:
1630       if ((p0 = c_getstr (arg0)) && (p1 = c_getstr (arg1)))
1631         {
1632           int r = strcmp (p0, p1);
1633           if (r == 0)
1634             return build_cmp_result (type, r);
1635         }
1636       return NULL_TREE;
1637
1638     case CFN_BUILT_IN_INDEX:
1639     case CFN_BUILT_IN_STRCHR:
1640       if ((p0 = c_getstr (arg0)) && target_char_cst_p (arg1, &c))
1641         {
1642           const char *r = strchr (p0, c);
1643           if (r == NULL)
1644             return build_int_cst (type, 0);
1645           return fold_convert (type,
1646                                fold_build_pointer_plus_hwi (arg0, r - p0));
1647         }
1648       return NULL_TREE;
1649
1650     case CFN_BUILT_IN_RINDEX:
1651     case CFN_BUILT_IN_STRRCHR:
1652       if ((p0 = c_getstr (arg0)) && target_char_cst_p (arg1, &c))
1653         {
1654           const char *r = strrchr (p0, c);
1655           if (r == NULL)
1656             return build_int_cst (type, 0);
1657           return fold_convert (type,
1658                                fold_build_pointer_plus_hwi (arg0, r - p0));
1659         }
1660       return NULL_TREE;
1661
1662     case CFN_BUILT_IN_STRSTR:
1663       if ((p1 = c_getstr (arg1)))
1664         {
1665           if ((p0 = c_getstr (arg0)))
1666             {
1667               const char *r = strstr (p0, p1);
1668               if (r == NULL)
1669                 return build_int_cst (type, 0);
1670               return fold_convert (type,
1671                                    fold_build_pointer_plus_hwi (arg0, r - p0));
1672             }
1673           if (*p1 == '\0')
1674             return fold_convert (type, arg0);
1675         }
1676       return NULL_TREE;
1677
1678     case CFN_FOLD_LEFT_PLUS:
1679       return fold_const_fold_left (type, arg0, arg1, PLUS_EXPR);
1680
1681     default:
1682       return fold_const_call_1 (fn, type, arg0, arg1);
1683     }
1684 }
1685
1686 /* Try to evaluate:
1687
1688       *RESULT = FN (*ARG0, *ARG1, *ARG2)
1689
1690    in format FORMAT.  Return true on success.  */
1691
1692 static bool
1693 fold_const_call_ssss (real_value *result, combined_fn fn,
1694                       const real_value *arg0, const real_value *arg1,
1695                       const real_value *arg2, const real_format *format)
1696 {
1697   switch (fn)
1698     {
1699     CASE_CFN_FMA:
1700     CASE_CFN_FMA_FN:
1701       return do_mpfr_arg3 (result, mpfr_fma, arg0, arg1, arg2, format);
1702
1703     case CFN_FMS:
1704       {
1705         real_value new_arg2 = real_value_negate (arg2);
1706         return do_mpfr_arg3 (result, mpfr_fma, arg0, arg1, &new_arg2, format);
1707       }
1708
1709     case CFN_FNMA:
1710       {
1711         real_value new_arg0 = real_value_negate (arg0);
1712         return do_mpfr_arg3 (result, mpfr_fma, &new_arg0, arg1, arg2, format);
1713       }
1714
1715     case CFN_FNMS:
1716       {
1717         real_value new_arg0 = real_value_negate (arg0);
1718         real_value new_arg2 = real_value_negate (arg2);
1719         return do_mpfr_arg3 (result, mpfr_fma, &new_arg0, arg1,
1720                              &new_arg2, format);
1721       }
1722
1723     default:
1724       return false;
1725     }
1726 }
1727
1728 /* Subroutine of fold_const_call, with the same interface.  Handle cases
1729    where the arguments and result are numerical.  */
1730
1731 static tree
1732 fold_const_call_1 (combined_fn fn, tree type, tree arg0, tree arg1, tree arg2)
1733 {
1734   machine_mode mode = TYPE_MODE (type);
1735   machine_mode arg0_mode = TYPE_MODE (TREE_TYPE (arg0));
1736   machine_mode arg1_mode = TYPE_MODE (TREE_TYPE (arg1));
1737   machine_mode arg2_mode = TYPE_MODE (TREE_TYPE (arg2));
1738
1739   if (arg0_mode == arg1_mode
1740       && arg0_mode == arg2_mode
1741       && real_cst_p (arg0)
1742       && real_cst_p (arg1)
1743       && real_cst_p (arg2))
1744     {
1745       gcc_checking_assert (SCALAR_FLOAT_MODE_P (arg0_mode));
1746       if (mode == arg0_mode)
1747         {
1748           /* real, real, real -> real.  */
1749           REAL_VALUE_TYPE result;
1750           if (fold_const_call_ssss (&result, fn, TREE_REAL_CST_PTR (arg0),
1751                                     TREE_REAL_CST_PTR (arg1),
1752                                     TREE_REAL_CST_PTR (arg2),
1753                                     REAL_MODE_FORMAT (mode)))
1754             return build_real (type, result);
1755         }
1756       return NULL_TREE;
1757     }
1758
1759   return NULL_TREE;
1760 }
1761
1762 /* Try to fold FN (ARG0, ARG1, ARG2) to a constant.  Return the constant on
1763    success, otherwise return null.  TYPE is the type of the return value.  */
1764
1765 tree
1766 fold_const_call (combined_fn fn, tree type, tree arg0, tree arg1, tree arg2)
1767 {
1768   const char *p0, *p1;
1769   char c;
1770   unsigned HOST_WIDE_INT s0, s1, s2 = 0;
1771   switch (fn)
1772     {
1773     case CFN_BUILT_IN_STRNCMP:
1774       if (!size_t_cst_p (arg2, &s2))
1775         return NULL_TREE;
1776       if (s2 == 0
1777           && !TREE_SIDE_EFFECTS (arg0)
1778           && !TREE_SIDE_EFFECTS (arg1))
1779         return build_int_cst (type, 0);
1780       else if ((p0 = c_getstr (arg0)) && (p1 = c_getstr (arg1)))
1781         return build_int_cst (type, strncmp (p0, p1, MIN (s2, SIZE_MAX)));
1782       return NULL_TREE;
1783
1784     case CFN_BUILT_IN_STRNCASECMP:
1785       if (!size_t_cst_p (arg2, &s2))
1786         return NULL_TREE;
1787       if (s2 == 0
1788           && !TREE_SIDE_EFFECTS (arg0)
1789           && !TREE_SIDE_EFFECTS (arg1))
1790         return build_int_cst (type, 0);
1791       else if ((p0 = c_getstr (arg0))
1792                && (p1 = c_getstr (arg1))
1793                && strncmp (p0, p1, MIN (s2, SIZE_MAX)) == 0)
1794         return build_int_cst (type, 0);
1795       return NULL_TREE;
1796
1797     case CFN_BUILT_IN_BCMP:
1798     case CFN_BUILT_IN_MEMCMP:
1799       if (!size_t_cst_p (arg2, &s2))
1800         return NULL_TREE;
1801       if (s2 == 0
1802           && !TREE_SIDE_EFFECTS (arg0)
1803           && !TREE_SIDE_EFFECTS (arg1))
1804         return build_int_cst (type, 0);
1805       if ((p0 = getbyterep (arg0, &s0))
1806           && (p1 = getbyterep (arg1, &s1))
1807           && s2 <= s0
1808           && s2 <= s1)
1809         return build_cmp_result (type, memcmp (p0, p1, s2));
1810       return NULL_TREE;
1811
1812     case CFN_BUILT_IN_MEMCHR:
1813       if (!size_t_cst_p (arg2, &s2))
1814         return NULL_TREE;
1815       if (s2 == 0
1816           && !TREE_SIDE_EFFECTS (arg0)
1817           && !TREE_SIDE_EFFECTS (arg1))
1818         return build_int_cst (type, 0);
1819       if ((p0 = getbyterep (arg0, &s0))
1820           && s2 <= s0
1821           && target_char_cst_p (arg1, &c))
1822         {
1823           const char *r = (const char *) memchr (p0, c, s2);
1824           if (r == NULL)
1825             return build_int_cst (type, 0);
1826           return fold_convert (type,
1827                                fold_build_pointer_plus_hwi (arg0, r - p0));
1828         }
1829       return NULL_TREE;
1830
1831     case CFN_WHILE_ULT:
1832       {
1833         poly_uint64 parg0, parg1;
1834         if (poly_int_tree_p (arg0, &parg0) && poly_int_tree_p (arg1, &parg1))
1835           return fold_while_ult (type, parg0, parg1);
1836         return NULL_TREE;
1837       }
1838
1839     default:
1840       return fold_const_call_1 (fn, type, arg0, arg1, arg2);
1841     }
1842 }