gcc/fold-const-call.c

   1 /* Constant folding for calls to built-in and internal functions.
   2    Copyright (C) 1988-2016 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #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
  34 /* Functions that test for certain constant types, abstracting away the
  35    decision about whether to check for overflow.  */
  36
  37 static inline bool
  38 integer_cst_p (tree t)
  39 {
  40   return TREE_CODE (t) == INTEGER_CST && !TREE_OVERFLOW (t);
  41 }
  42
  43 static inline bool
  44 real_cst_p (tree t)
  45 {
  46   return TREE_CODE (t) == REAL_CST && !TREE_OVERFLOW (t);
  47 }
  48
  49 static inline bool
  50 complex_cst_p (tree t)
  51 {
  52   return TREE_CODE (t) == COMPLEX_CST;
  53 }
  54
  55 /* Return true if ARG is a constant in the range of the host size_t.
  56    Store it in *SIZE_OUT if so.  */
  57
  58 static inline bool
  59 host_size_t_cst_p (tree t, size_t *size_out)
  60 {
  61   if (types_compatible_p (size_type_node, TREE_TYPE (t))
  62       && integer_cst_p (t)
  63       && wi::min_precision (t, UNSIGNED) <= sizeof (size_t) * CHAR_BIT)
  64     {
  65       *size_out = tree_to_uhwi (t);
  66       return true;
  67     }
  68   return false;
  69 }
  70
  71 /* RES is the result of a comparison in which < 0 means "less", 0 means
  72    "equal" and > 0 means "more".  Canonicalize it to -1, 0 or 1 and
  73    return it in type TYPE.  */
  74
  75 tree
  76 build_cmp_result (tree type, int res)
  77 {
  78   return build_int_cst (type, res < 0 ? -1 : res > 0 ? 1 : 0);
  79 }
  80
  81 /* M is the result of trying to constant-fold an expression (starting
  82    with clear MPFR flags) and INEXACT says whether the result in M is
  83    exact or inexact.  Return true if M can be used as a constant-folded
  84    result in format FORMAT, storing the value in *RESULT if so.  */
  85
  86 static bool
  87 do_mpfr_ckconv (real_value *result, mpfr_srcptr m, bool inexact,
  88                 const real_format *format)
  89 {
  90   /* Proceed iff we get a normal number, i.e. not NaN or Inf and no
  91      overflow/underflow occurred.  If -frounding-math, proceed iff the
  92      result of calling FUNC was exact.  */
  93   if (!mpfr_number_p (m)
  94       || mpfr_overflow_p ()
  95       || mpfr_underflow_p ()
  96       || (flag_rounding_math && inexact))
  97     return false;
  98
  99   REAL_VALUE_TYPE tmp;
 100   real_from_mpfr (&tmp, m, format, GMP_RNDN);
 101
 102   /* Proceed iff GCC's REAL_VALUE_TYPE can hold the MPFR values.
 103      If the REAL_VALUE_TYPE is zero but the mpft_t is not, then we
 104      underflowed in the conversion.  */
 105   if (!real_isfinite (&tmp)
 106       || ((tmp.cl == rvc_zero) != (mpfr_zero_p (m) != 0)))
 107     return false;
 108
 109   real_convert (result, format, &tmp);
 110   return real_identical (result, &tmp);
 111 }
 112
 113 /* Try to evaluate:
 114
 115       *RESULT = f (*ARG)
 116
 117    in format FORMAT, given that FUNC is the MPFR implementation of f.
 118    Return true on success.  */
 119
 120 static bool
 121 do_mpfr_arg1 (real_value *result,
 122               int (*func) (mpfr_ptr, mpfr_srcptr, mpfr_rnd_t),
 123               const real_value *arg, const real_format *format)
 124 {
 125   /* To proceed, MPFR must exactly represent the target floating point
 126      format, which only happens when the target base equals two.  */
 127   if (format->b != 2 || !real_isfinite (arg))
 128     return false;
 129
 130   int prec = format->p;
 131   mp_rnd_t rnd = format->round_towards_zero ? GMP_RNDZ : GMP_RNDN;
 132   mpfr_t m;
 133
 134   mpfr_init2 (m, prec);
 135   mpfr_from_real (m, arg, GMP_RNDN);
 136   mpfr_clear_flags ();
 137   bool inexact = func (m, m, rnd);
 138   bool ok = do_mpfr_ckconv (result, m, inexact, format);
 139   mpfr_clear (m);
 140
 141   return ok;
 142 }
 143
 144 /* Try to evaluate:
 145
 146       *RESULT_SIN = sin (*ARG);
 147       *RESULT_COS = cos (*ARG);
 148
 149    for format FORMAT.  Return true on success.  */
 150
 151 static bool
 152 do_mpfr_sincos (real_value *result_sin, real_value *result_cos,
 153                 const real_value *arg, const real_format *format)
 154 {
 155   /* To proceed, MPFR must exactly represent the target floating point
 156      format, which only happens when the target base equals two.  */
 157   if (format->b != 2 || !real_isfinite (arg))
 158     return false;
 159
 160   int prec = format->p;
 161   mp_rnd_t rnd = format->round_towards_zero ? GMP_RNDZ : GMP_RNDN;
 162   mpfr_t m, ms, mc;
 163
 164   mpfr_inits2 (prec, m, ms, mc, NULL);
 165   mpfr_from_real (m, arg, GMP_RNDN);
 166   mpfr_clear_flags ();
 167   bool inexact = mpfr_sin_cos (ms, mc, m, rnd);
 168   bool ok = (do_mpfr_ckconv (result_sin, ms, inexact, format)
 169              && do_mpfr_ckconv (result_cos, mc, inexact, format));
 170   mpfr_clears (m, ms, mc, NULL);
 171
 172   return ok;
 173 }
 174
 175 /* Try to evaluate:
 176
 177       *RESULT = f (*ARG0, *ARG1)
 178
 179    in format FORMAT, given that FUNC is the MPFR implementation of f.
 180    Return true on success.  */
 181
 182 static bool
 183 do_mpfr_arg2 (real_value *result,
 184               int (*func) (mpfr_ptr, mpfr_srcptr, mpfr_srcptr, mpfr_rnd_t),
 185               const real_value *arg0, const real_value *arg1,
 186               const real_format *format)
 187 {
 188   /* To proceed, MPFR must exactly represent the target floating point
 189      format, which only happens when the target base equals two.  */
 190   if (format->b != 2 || !real_isfinite (arg0) || !real_isfinite (arg1))
 191     return false;
 192
 193   int prec = format->p;
 194   mp_rnd_t rnd = format->round_towards_zero ? GMP_RNDZ : GMP_RNDN;
 195   mpfr_t m0, m1;
 196
 197   mpfr_inits2 (prec, m0, m1, NULL);
 198   mpfr_from_real (m0, arg0, GMP_RNDN);
 199   mpfr_from_real (m1, arg1, GMP_RNDN);
 200   mpfr_clear_flags ();
 201   bool inexact = func (m0, m0, m1, rnd);
 202   bool ok = do_mpfr_ckconv (result, m0, inexact, format);
 203   mpfr_clears (m0, m1, NULL);
 204
 205   return ok;
 206 }
 207
 208 /* Try to evaluate:
 209
 210       *RESULT = f (ARG0, *ARG1)
 211
 212    in format FORMAT, given that FUNC is the MPFR implementation of f.
 213    Return true on success.  */
 214
 215 static bool
 216 do_mpfr_arg2 (real_value *result,
 217               int (*func) (mpfr_ptr, long, mpfr_srcptr, mp_rnd_t),
 218               const wide_int_ref &arg0, const real_value *arg1,
 219               const real_format *format)
 220 {
 221   if (format->b != 2 || !real_isfinite (arg1))
 222     return false;
 223
 224   int prec = format->p;
 225   mp_rnd_t rnd = format->round_towards_zero ? GMP_RNDZ : GMP_RNDN;
 226   mpfr_t m;
 227
 228   mpfr_init2 (m, prec);
 229   mpfr_from_real (m, arg1, GMP_RNDN);
 230   mpfr_clear_flags ();
 231   bool inexact = func (m, arg0.to_shwi (), m, rnd);
 232   bool ok = do_mpfr_ckconv (result, m, inexact, format);
 233   mpfr_clear (m);
 234
 235   return ok;
 236 }
 237
 238 /* Try to evaluate:
 239
 240       *RESULT = f (*ARG0, *ARG1, *ARG2)
 241
 242    in format FORMAT, given that FUNC is the MPFR implementation of f.
 243    Return true on success.  */
 244
 245 static bool
 246 do_mpfr_arg3 (real_value *result,
 247               int (*func) (mpfr_ptr, mpfr_srcptr, mpfr_srcptr,
 248                            mpfr_srcptr, mpfr_rnd_t),
 249               const real_value *arg0, const real_value *arg1,
 250               const real_value *arg2, const real_format *format)
 251 {
 252   /* To proceed, MPFR must exactly represent the target floating point
 253      format, which only happens when the target base equals two.  */
 254   if (format->b != 2
 255       || !real_isfinite (arg0)
 256       || !real_isfinite (arg1)
 257       || !real_isfinite (arg2))
 258     return false;
 259
 260   int prec = format->p;
 261   mp_rnd_t rnd = format->round_towards_zero ? GMP_RNDZ : GMP_RNDN;
 262   mpfr_t m0, m1, m2;
 263
 264   mpfr_inits2 (prec, m0, m1, m2, NULL);
 265   mpfr_from_real (m0, arg0, GMP_RNDN);
 266   mpfr_from_real (m1, arg1, GMP_RNDN);
 267   mpfr_from_real (m2, arg2, GMP_RNDN);
 268   mpfr_clear_flags ();
 269   bool inexact = func (m0, m0, m1, m2, rnd);
 270   bool ok = do_mpfr_ckconv (result, m0, inexact, format);
 271   mpfr_clears (m0, m1, m2, NULL);
 272
 273   return ok;
 274 }
 275
 276 /* M is the result of trying to constant-fold an expression (starting
 277    with clear MPFR flags) and INEXACT says whether the result in M is
 278    exact or inexact.  Return true if M can be used as a constant-folded
 279    result in which the real and imaginary parts have format FORMAT.
 280    Store those parts in *RESULT_REAL and *RESULT_IMAG if so.  */
 281
 282 static bool
 283 do_mpc_ckconv (real_value *result_real, real_value *result_imag,
 284                mpc_srcptr m, bool inexact, const real_format *format)
 285 {
 286   /* Proceed iff we get a normal number, i.e. not NaN or Inf and no
 287      overflow/underflow occurred.  If -frounding-math, proceed iff the
 288      result of calling FUNC was exact.  */
 289   if (!mpfr_number_p (mpc_realref (m))
 290       || !mpfr_number_p (mpc_imagref (m))
 291       || mpfr_overflow_p ()
 292       || mpfr_underflow_p ()
 293       || (flag_rounding_math && inexact))
 294     return false;
 295
 296   REAL_VALUE_TYPE tmp_real, tmp_imag;
 297   real_from_mpfr (&tmp_real, mpc_realref (m), format, GMP_RNDN);
 298   real_from_mpfr (&tmp_imag, mpc_imagref (m), format, GMP_RNDN);
 299
 300   /* Proceed iff GCC's REAL_VALUE_TYPE can hold the MPFR values.
 301      If the REAL_VALUE_TYPE is zero but the mpft_t is not, then we
 302      underflowed in the conversion.  */
 303   if (!real_isfinite (&tmp_real)
 304       || !real_isfinite (&tmp_imag)
 305       || (tmp_real.cl == rvc_zero) != (mpfr_zero_p (mpc_realref (m)) != 0)
 306       || (tmp_imag.cl == rvc_zero) != (mpfr_zero_p (mpc_imagref (m)) != 0))
 307     return false;
 308
 309   real_convert (result_real, format, &tmp_real);
 310   real_convert (result_imag, format, &tmp_imag);
 311
 312   return (real_identical (result_real, &tmp_real)
 313           && real_identical (result_imag, &tmp_imag));
 314 }
 315
 316 /* Try to evaluate:
 317
 318       RESULT = f (ARG)
 319
 320    in format FORMAT, given that FUNC is the mpc implementation of f.
 321    Return true on success.  Both RESULT and ARG are represented as
 322    real and imaginary pairs.  */
 323
 324 static bool
 325 do_mpc_arg1 (real_value *result_real, real_value *result_imag,
 326              int (*func) (mpc_ptr, mpc_srcptr, mpc_rnd_t),
 327              const real_value *arg_real, const real_value *arg_imag,
 328              const real_format *format)
 329 {
 330   /* To proceed, MPFR must exactly represent the target floating point
 331      format, which only happens when the target base equals two.  */
 332   if (format->b != 2
 333       || !real_isfinite (arg_real)
 334       || !real_isfinite (arg_imag))
 335     return false;
 336
 337   int prec = format->p;
 338   mpc_rnd_t crnd = format->round_towards_zero ? MPC_RNDZZ : MPC_RNDNN;
 339   mpc_t m;
 340
 341   mpc_init2 (m, prec);
 342   mpfr_from_real (mpc_realref (m), arg_real, GMP_RNDN);
 343   mpfr_from_real (mpc_imagref (m), arg_imag, GMP_RNDN);
 344   mpfr_clear_flags ();
 345   bool inexact = func (m, m, crnd);
 346   bool ok = do_mpc_ckconv (result_real, result_imag, m, inexact, format);
 347   mpc_clear (m);
 348
 349   return ok;
 350 }
 351
 352 /* Try to evaluate:
 353
 354       RESULT = f (ARG0, ARG1)
 355
 356    in format FORMAT, given that FUNC is the mpc implementation of f.
 357    Return true on success.  RESULT, ARG0 and ARG1 are represented as
 358    real and imaginary pairs.  */
 359
 360 static bool
 361 do_mpc_arg2 (real_value *result_real, real_value *result_imag,
 362              int (*func)(mpc_ptr, mpc_srcptr, mpc_srcptr, mpc_rnd_t),
 363              const real_value *arg0_real, const real_value *arg0_imag,
 364              const real_value *arg1_real, const real_value *arg1_imag,
 365              const real_format *format)
 366 {
 367   if (!real_isfinite (arg0_real)
 368       || !real_isfinite (arg0_imag)
 369       || !real_isfinite (arg1_real)
 370       || !real_isfinite (arg1_imag))
 371     return false;
 372
 373   int prec = format->p;
 374   mpc_rnd_t crnd = format->round_towards_zero ? MPC_RNDZZ : MPC_RNDNN;
 375   mpc_t m0, m1;
 376
 377   mpc_init2 (m0, prec);
 378   mpc_init2 (m1, prec);
 379   mpfr_from_real (mpc_realref (m0), arg0_real, GMP_RNDN);
 380   mpfr_from_real (mpc_imagref (m0), arg0_imag, GMP_RNDN);
 381   mpfr_from_real (mpc_realref (m1), arg1_real, GMP_RNDN);
 382   mpfr_from_real (mpc_imagref (m1), arg1_imag, GMP_RNDN);
 383   mpfr_clear_flags ();
 384   bool inexact = func (m0, m0, m1, crnd);
 385   bool ok = do_mpc_ckconv (result_real, result_imag, m0, inexact, format);
 386   mpc_clear (m0);
 387   mpc_clear (m1);
 388
 389   return ok;
 390 }
 391
 392 /* Try to evaluate:
 393
 394       *RESULT = logb (*ARG)
 395
 396    in format FORMAT.  Return true on success.  */
 397
 398 static bool
 399 fold_const_logb (real_value *result, const real_value *arg,
 400                  const real_format *format)
 401 {
 402   switch (arg->cl)
 403     {
 404     case rvc_nan:
 405       /* If arg is +-NaN, then return it.  */
 406       *result = *arg;
 407       return true;
 408
 409     case rvc_inf:
 410       /* If arg is +-Inf, then return +Inf.  */
 411       *result = *arg;
 412       result->sign = 0;
 413       return true;
 414
 415     case rvc_zero:
 416       /* Zero may set errno and/or raise an exception.  */
 417       return false;
 418
 419     case rvc_normal:
 420       /* For normal numbers, proceed iff radix == 2.  In GCC,
 421          normalized significands are in the range [0.5, 1.0).  We
 422          want the exponent as if they were [1.0, 2.0) so get the
 423          exponent and subtract 1.  */
 424       if (format->b == 2)
 425         {
 426           real_from_integer (result, format, REAL_EXP (arg) - 1, SIGNED);
 427           return true;
 428         }
 429       return false;
 430     }
 431   gcc_unreachable ();
 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   gcc_unreachable ();
 466 }
 467
 468 /* Try to evaluate:
 469
 470       *RESULT = f (*ARG)
 471
 472    where FORMAT is the format of *ARG and PRECISION is the number of
 473    significant bits in the result.  Return true on success.  */
 474
 475 static bool
 476 fold_const_conversion (wide_int *result,
 477                        void (*fn) (real_value *, format_helper,
 478                                    const real_value *),
 479                        const real_value *arg, unsigned int precision,
 480                        const real_format *format)
 481 {
 482   if (!real_isfinite (arg))
 483     return false;
 484
 485   real_value rounded;
 486   fn (&rounded, format, arg);
 487
 488   bool fail = false;
 489   *result = real_to_integer (&rounded, &fail, precision);
 490   return !fail;
 491 }
 492
 493 /* Try to evaluate:
 494
 495       *RESULT = pow (*ARG0, *ARG1)
 496
 497    in format FORMAT.  Return true on success.  */
 498
 499 static bool
 500 fold_const_pow (real_value *result, const real_value *arg0,
 501                 const real_value *arg1, const real_format *format)
 502 {
 503   if (do_mpfr_arg2 (result, mpfr_pow, arg0, arg1, format))
 504     return true;
 505
 506   /* Check for an integer exponent.  */
 507   REAL_VALUE_TYPE cint1;
 508   HOST_WIDE_INT n1 = real_to_integer (arg1);
 509   real_from_integer (&cint1, VOIDmode, n1, SIGNED);
 510   /* Attempt to evaluate pow at compile-time, unless this should
 511      raise an exception.  */
 512   if (real_identical (arg1, &cint1)
 513       && (n1 > 0
 514           || (!flag_trapping_math && !flag_errno_math)
 515           || !real_equal (arg0, &dconst0)))
 516     {
 517       bool inexact = real_powi (result, format, arg0, n1);
 518       /* Avoid the folding if flag_signaling_nans is on.  */
 519       if (flag_unsafe_math_optimizations
 520           || (!inexact
 521               && !(flag_signaling_nans
 522                    && REAL_VALUE_ISSIGNALING_NAN (*arg0))))
 523         return true;
 524     }
 525
 526   return false;
 527 }
 528
 529 /* Try to evaluate:
 530
 531       *RESULT = ldexp (*ARG0, ARG1)
 532
 533    in format FORMAT.  Return true on success.  */
 534
 535 static bool
 536 fold_const_builtin_load_exponent (real_value *result, const real_value *arg0,
 537                                   const wide_int_ref &arg1,
 538                                   const real_format *format)
 539 {
 540   /* Bound the maximum adjustment to twice the range of the
 541      mode's valid exponents.  Use abs to ensure the range is
 542      positive as a sanity check.  */
 543   int max_exp_adj = 2 * labs (format->emax - format->emin);
 544
 545   /* The requested adjustment must be inside this range.  This
 546      is a preliminary cap to avoid things like overflow, we
 547      may still fail to compute the result for other reasons.  */
 548   if (wi::les_p (arg1, -max_exp_adj) || wi::ges_p (arg1, max_exp_adj))
 549     return false;
 550
 551   /* Don't perform operation if we honor signaling NaNs and
 552      operand is a signaling NaN.  */
 553   if (!flag_unsafe_math_optimizations
 554       && flag_signaling_nans
 555       && REAL_VALUE_ISSIGNALING_NAN (*arg0))
 556     return false;
 557
 558   REAL_VALUE_TYPE initial_result;
 559   real_ldexp (&initial_result, arg0, arg1.to_shwi ());
 560
 561   /* Ensure we didn't overflow.  */
 562   if (real_isinf (&initial_result))
 563     return false;
 564
 565   /* Only proceed if the target mode can hold the
 566      resulting value.  */
 567   *result = real_value_truncate (format, initial_result);
 568   return real_equal (&initial_result, result);
 569 }
 570
 571 /* Fold a call to __builtin_nan or __builtin_nans with argument ARG and
 572    return type TYPE.  QUIET is true if a quiet rather than signalling
 573    NaN is required.  */
 574
 575 static tree
 576 fold_const_builtin_nan (tree type, tree arg, bool quiet)
 577 {
 578   REAL_VALUE_TYPE real;
 579   const char *str = c_getstr (arg);
 580   if (str && real_nan (&real, str, quiet, TYPE_MODE (type)))
 581     return build_real (type, real);
 582   return NULL_TREE;
 583 }
 584
 585 /* Try to evaluate:
 586
 587       *RESULT = FN (*ARG)
 588
 589    in format FORMAT.  Return true on success.  */
 590
 591 static bool
 592 fold_const_call_ss (real_value *result, combined_fn fn,
 593                     const real_value *arg, const real_format *format)
 594 {
 595   switch (fn)
 596     {
 597     CASE_CFN_SQRT:
 598       return (real_compare (GE_EXPR, arg, &dconst0)
 599               && do_mpfr_arg1 (result, mpfr_sqrt, arg, format));
 600
 601     CASE_CFN_CBRT:
 602       return do_mpfr_arg1 (result, mpfr_cbrt, arg, format);
 603
 604     CASE_CFN_ASIN:
 605       return (real_compare (GE_EXPR, arg, &dconstm1)
 606               && real_compare (LE_EXPR, arg, &dconst1)
 607               && do_mpfr_arg1 (result, mpfr_asin, arg, format));
 608
 609     CASE_CFN_ACOS:
 610       return (real_compare (GE_EXPR, arg, &dconstm1)
 611               && real_compare (LE_EXPR, arg, &dconst1)
 612               && do_mpfr_arg1 (result, mpfr_acos, arg, format));
 613
 614     CASE_CFN_ATAN:
 615       return do_mpfr_arg1 (result, mpfr_atan, arg, format);
 616
 617     CASE_CFN_ASINH:
 618       return do_mpfr_arg1 (result, mpfr_asinh, arg, format);
 619
 620     CASE_CFN_ACOSH:
 621       return (real_compare (GE_EXPR, arg, &dconst1)
 622               && do_mpfr_arg1 (result, mpfr_acosh, arg, format));
 623
 624     CASE_CFN_ATANH:
 625       return (real_compare (GE_EXPR, arg, &dconstm1)
 626               && real_compare (LE_EXPR, arg, &dconst1)
 627               && do_mpfr_arg1 (result, mpfr_atanh, arg, format));
 628
 629     CASE_CFN_SIN:
 630       return do_mpfr_arg1 (result, mpfr_sin, arg, format);
 631
 632     CASE_CFN_COS:
 633       return do_mpfr_arg1 (result, mpfr_cos, arg, format);
 634
 635     CASE_CFN_TAN:
 636       return do_mpfr_arg1 (result, mpfr_tan, arg, format);
 637
 638     CASE_CFN_SINH:
 639       return do_mpfr_arg1 (result, mpfr_sinh, arg, format);
 640
 641     CASE_CFN_COSH:
 642       return do_mpfr_arg1 (result, mpfr_cosh, arg, format);
 643
 644     CASE_CFN_TANH:
 645       return do_mpfr_arg1 (result, mpfr_tanh, arg, format);
 646
 647     CASE_CFN_ERF:
 648       return do_mpfr_arg1 (result, mpfr_erf, arg, format);
 649
 650     CASE_CFN_ERFC:
 651       return do_mpfr_arg1 (result, mpfr_erfc, arg, format);
 652
 653     CASE_CFN_TGAMMA:
 654       return do_mpfr_arg1 (result, mpfr_gamma, arg, format);
 655
 656     CASE_CFN_EXP:
 657       return do_mpfr_arg1 (result, mpfr_exp, arg, format);
 658
 659     CASE_CFN_EXP2:
 660       return do_mpfr_arg1 (result, mpfr_exp2, arg, format);
 661
 662     CASE_CFN_EXP10:
 663     CASE_CFN_POW10:
 664       return do_mpfr_arg1 (result, mpfr_exp10, arg, format);
 665
 666     CASE_CFN_EXPM1:
 667       return do_mpfr_arg1 (result, mpfr_expm1, arg, format);
 668
 669     CASE_CFN_LOG:
 670       return (real_compare (GT_EXPR, arg, &dconst0)
 671               && do_mpfr_arg1 (result, mpfr_log, arg, format));
 672
 673     CASE_CFN_LOG2:
 674       return (real_compare (GT_EXPR, arg, &dconst0)
 675               && do_mpfr_arg1 (result, mpfr_log2, arg, format));
 676
 677     CASE_CFN_LOG10:
 678       return (real_compare (GT_EXPR, arg, &dconst0)
 679               && do_mpfr_arg1 (result, mpfr_log10, arg, format));
 680
 681     CASE_CFN_LOG1P:
 682       return (real_compare (GT_EXPR, arg, &dconstm1)
 683               && do_mpfr_arg1 (result, mpfr_log1p, arg, format));
 684
 685     CASE_CFN_J0:
 686       return do_mpfr_arg1 (result, mpfr_j0, arg, format);
 687
 688     CASE_CFN_J1:
 689       return do_mpfr_arg1 (result, mpfr_j1, arg, format);
 690
 691     CASE_CFN_Y0:
 692       return (real_compare (GT_EXPR, arg, &dconst0)
 693               && do_mpfr_arg1 (result, mpfr_y0, arg, format));
 694
 695     CASE_CFN_Y1:
 696       return (real_compare (GT_EXPR, arg, &dconst0)
 697               && do_mpfr_arg1 (result, mpfr_y1, arg, format));
 698
 699     CASE_CFN_FLOOR:
 700       if (!REAL_VALUE_ISNAN (*arg) || !flag_errno_math)
 701         {
 702           real_floor (result, format, arg);
 703           return true;
 704         }
 705       return false;
 706
 707     CASE_CFN_CEIL:
 708       if (!REAL_VALUE_ISNAN (*arg) || !flag_errno_math)
 709         {
 710           real_ceil (result, format, arg);
 711           return true;
 712         }
 713       return false;
 714
 715     CASE_CFN_TRUNC:
 716       real_trunc (result, format, arg);
 717       return true;
 718
 719     CASE_CFN_ROUND:
 720       if (!REAL_VALUE_ISNAN (*arg) || !flag_errno_math)
 721         {
 722           real_round (result, format, arg);
 723           return true;
 724         }
 725       return false;
 726
 727     CASE_CFN_LOGB:
 728       return fold_const_logb (result, arg, format);
 729
 730     CASE_CFN_SIGNIFICAND:
 731       return fold_const_significand (result, arg, format);
 732
 733     default:
 734       return false;
 735     }
 736 }
 737
 738 /* Try to evaluate:
 739
 740       *RESULT = FN (*ARG)
 741
 742    where FORMAT is the format of ARG and PRECISION is the number of
 743    significant bits in the result.  Return true on success.  */
 744
 745 static bool
 746 fold_const_call_ss (wide_int *result, combined_fn fn,
 747                     const real_value *arg, unsigned int precision,
 748                     const real_format *format)
 749 {
 750   switch (fn)
 751     {
 752     CASE_CFN_SIGNBIT:
 753       if (real_isneg (arg))
 754         *result = wi::one (precision);
 755       else
 756         *result = wi::zero (precision);
 757       return true;
 758
 759     CASE_CFN_ILOGB:
 760       /* For ilogb we don't know FP_ILOGB0, so only handle normal values.
 761          Proceed iff radix == 2.  In GCC, normalized significands are in
 762          the range [0.5, 1.0).  We want the exponent as if they were
 763          [1.0, 2.0) so get the exponent and subtract 1.  */
 764       if (arg->cl == rvc_normal && format->b == 2)
 765         {
 766           *result = wi::shwi (REAL_EXP (arg) - 1, precision);
 767           return true;
 768         }
 769       return false;
 770
 771     CASE_CFN_ICEIL:
 772     CASE_CFN_LCEIL:
 773     CASE_CFN_LLCEIL:
 774       return fold_const_conversion (result, real_ceil, arg,
 775                                     precision, format);
 776
 777     CASE_CFN_LFLOOR:
 778     CASE_CFN_IFLOOR:
 779     CASE_CFN_LLFLOOR:
 780       return fold_const_conversion (result, real_floor, arg,
 781                                     precision, format);
 782
 783     CASE_CFN_IROUND:
 784     CASE_CFN_LROUND:
 785     CASE_CFN_LLROUND:
 786       return fold_const_conversion (result, real_round, arg,
 787                                     precision, format);
 788
 789     CASE_CFN_IRINT:
 790     CASE_CFN_LRINT:
 791     CASE_CFN_LLRINT:
 792       /* Not yet folded to a constant.  */
 793       return false;
 794
 795     CASE_CFN_FINITE:
 796     case CFN_BUILT_IN_FINITED32:
 797     case CFN_BUILT_IN_FINITED64:
 798     case CFN_BUILT_IN_FINITED128:
 799     case CFN_BUILT_IN_ISFINITE:
 800       *result = wi::shwi (real_isfinite (arg) ? 1 : 0, precision);
 801       return true;
 802
 803     CASE_CFN_ISINF:
 804     case CFN_BUILT_IN_ISINFD32:
 805     case CFN_BUILT_IN_ISINFD64:
 806     case CFN_BUILT_IN_ISINFD128:
 807       if (real_isinf (arg))
 808         *result = wi::shwi (arg->sign ? -1 : 1, precision);
 809       else
 810         *result = wi::shwi (0, precision);
 811       return true;
 812
 813     CASE_CFN_ISNAN:
 814     case CFN_BUILT_IN_ISNAND32:
 815     case CFN_BUILT_IN_ISNAND64:
 816     case CFN_BUILT_IN_ISNAND128:
 817       *result = wi::shwi (real_isnan (arg) ? 1 : 0, precision);
 818       return true;
 819
 820     default:
 821       return false;
 822     }
 823 }
 824
 825 /* Try to evaluate:
 826
 827       *RESULT = FN (ARG)
 828
 829    where ARG_TYPE is the type of ARG and PRECISION is the number of bits
 830    in the result.  Return true on success.  */
 831
 832 static bool
 833 fold_const_call_ss (wide_int *result, combined_fn fn, const wide_int_ref &arg,
 834                     unsigned int precision, tree arg_type)
 835 {
 836   switch (fn)
 837     {
 838     CASE_CFN_FFS:
 839       *result = wi::shwi (wi::ffs (arg), precision);
 840       return true;
 841
 842     CASE_CFN_CLZ:
 843       {
 844         int tmp;
 845         if (wi::ne_p (arg, 0))
 846           tmp = wi::clz (arg);
 847         else if (! CLZ_DEFINED_VALUE_AT_ZERO (TYPE_MODE (arg_type), tmp))
 848           tmp = TYPE_PRECISION (arg_type);
 849         *result = wi::shwi (tmp, precision);
 850         return true;
 851       }
 852
 853     CASE_CFN_CTZ:
 854       {
 855         int tmp;
 856         if (wi::ne_p (arg, 0))
 857           tmp = wi::ctz (arg);
 858         else if (! CTZ_DEFINED_VALUE_AT_ZERO (TYPE_MODE (arg_type), tmp))
 859           tmp = TYPE_PRECISION (arg_type);
 860         *result = wi::shwi (tmp, precision);
 861         return true;
 862       }
 863
 864     CASE_CFN_CLRSB:
 865       *result = wi::shwi (wi::clrsb (arg), precision);
 866       return true;
 867
 868     CASE_CFN_POPCOUNT:
 869       *result = wi::shwi (wi::popcount (arg), precision);
 870       return true;
 871
 872     CASE_CFN_PARITY:
 873       *result = wi::shwi (wi::parity (arg), precision);
 874       return true;
 875
 876     case CFN_BUILT_IN_BSWAP16:
 877     case CFN_BUILT_IN_BSWAP32:
 878     case CFN_BUILT_IN_BSWAP64:
 879       *result = wide_int::from (arg, precision, TYPE_SIGN (arg_type)).bswap ();
 880       return true;
 881
 882     default:
 883       return false;
 884     }
 885 }
 886
 887 /* Try to evaluate:
 888
 889       RESULT = FN (*ARG)
 890
 891    where FORMAT is the format of ARG and of the real and imaginary parts
 892    of RESULT, passed as RESULT_REAL and RESULT_IMAG respectively.  Return
 893    true on success.  */
 894
 895 static bool
 896 fold_const_call_cs (real_value *result_real, real_value *result_imag,
 897                     combined_fn fn, const real_value *arg,
 898                     const real_format *format)
 899 {
 900   switch (fn)
 901     {
 902     CASE_CFN_CEXPI:
 903       /* cexpi(x+yi) = cos(x)+sin(y)*i.  */
 904       return do_mpfr_sincos (result_imag, result_real, arg, format);
 905
 906     default:
 907       return false;
 908     }
 909 }
 910
 911 /* Try to evaluate:
 912
 913       *RESULT = fn (ARG)
 914
 915    where FORMAT is the format of RESULT and of the real and imaginary parts
 916    of ARG, passed as ARG_REAL and ARG_IMAG respectively.  Return true on
 917    success.  */
 918
 919 static bool
 920 fold_const_call_sc (real_value *result, combined_fn fn,
 921                     const real_value *arg_real, const real_value *arg_imag,
 922                     const real_format *format)
 923 {
 924   switch (fn)
 925     {
 926     CASE_CFN_CABS:
 927       return do_mpfr_arg2 (result, mpfr_hypot, arg_real, arg_imag, format);
 928
 929     default:
 930       return false;
 931     }
 932 }
 933
 934 /* Try to evaluate:
 935
 936       RESULT = fn (ARG)
 937
 938    where FORMAT is the format of the real and imaginary parts of RESULT
 939    (RESULT_REAL and RESULT_IMAG) and of ARG (ARG_REAL and ARG_IMAG).
 940    Return true on success.  */
 941
 942 static bool
 943 fold_const_call_cc (real_value *result_real, real_value *result_imag,
 944                     combined_fn fn, const real_value *arg_real,
 945                     const real_value *arg_imag, const real_format *format)
 946 {
 947   switch (fn)
 948     {
 949     CASE_CFN_CCOS:
 950       return do_mpc_arg1 (result_real, result_imag, mpc_cos,
 951                           arg_real, arg_imag, format);
 952
 953     CASE_CFN_CCOSH:
 954       return do_mpc_arg1 (result_real, result_imag, mpc_cosh,
 955                           arg_real, arg_imag, format);
 956
 957     CASE_CFN_CPROJ:
 958       if (real_isinf (arg_real) || real_isinf (arg_imag))
 959         {
 960           real_inf (result_real);
 961           *result_imag = dconst0;
 962           result_imag->sign = arg_imag->sign;
 963         }
 964       else
 965         {
 966           *result_real = *arg_real;
 967           *result_imag = *arg_imag;
 968         }
 969       return true;
 970
 971     CASE_CFN_CSIN:
 972       return do_mpc_arg1 (result_real, result_imag, mpc_sin,
 973                           arg_real, arg_imag, format);
 974
 975     CASE_CFN_CSINH:
 976       return do_mpc_arg1 (result_real, result_imag, mpc_sinh,
 977                           arg_real, arg_imag, format);
 978
 979     CASE_CFN_CTAN:
 980       return do_mpc_arg1 (result_real, result_imag, mpc_tan,
 981                           arg_real, arg_imag, format);
 982
 983     CASE_CFN_CTANH:
 984       return do_mpc_arg1 (result_real, result_imag, mpc_tanh,
 985                           arg_real, arg_imag, format);
 986
 987     CASE_CFN_CLOG:
 988       return do_mpc_arg1 (result_real, result_imag, mpc_log,
 989                           arg_real, arg_imag, format);
 990
 991     CASE_CFN_CSQRT:
 992       return do_mpc_arg1 (result_real, result_imag, mpc_sqrt,
 993                           arg_real, arg_imag, format);
 994
 995     CASE_CFN_CASIN:
 996       return do_mpc_arg1 (result_real, result_imag, mpc_asin,
 997                           arg_real, arg_imag, format);
 998
 999     CASE_CFN_CACOS:
1000       return do_mpc_arg1 (result_real, result_imag, mpc_acos,
1001                           arg_real, arg_imag, format);
1002
1003     CASE_CFN_CATAN:
1004       return do_mpc_arg1 (result_real, result_imag, mpc_atan,
1005                           arg_real, arg_imag, format);
1006
1007     CASE_CFN_CASINH:
1008       return do_mpc_arg1 (result_real, result_imag, mpc_asinh,
1009                           arg_real, arg_imag, format);
1010
1011     CASE_CFN_CACOSH:
1012       return do_mpc_arg1 (result_real, result_imag, mpc_acosh,
1013                           arg_real, arg_imag, format);
1014
1015     CASE_CFN_CATANH:
1016       return do_mpc_arg1 (result_real, result_imag, mpc_atanh,
1017                           arg_real, arg_imag, format);
1018
1019     CASE_CFN_CEXP:
1020       return do_mpc_arg1 (result_real, result_imag, mpc_exp,
1021                           arg_real, arg_imag, format);
1022
1023     default:
1024       return false;
1025     }
1026 }
1027
1028 /* Subroutine of fold_const_call, with the same interface.  Handle cases
1029    where the arguments and result are numerical.  */
1030
1031 static tree
1032 fold_const_call_1 (combined_fn fn, tree type, tree arg)
1033 {
1034   machine_mode mode = TYPE_MODE (type);
1035   machine_mode arg_mode = TYPE_MODE (TREE_TYPE (arg));
1036
1037   if (integer_cst_p (arg))
1038     {
1039       if (SCALAR_INT_MODE_P (mode))
1040         {
1041           wide_int result;
1042           if (fold_const_call_ss (&result, fn, arg, TYPE_PRECISION (type),
1043                                   TREE_TYPE (arg)))
1044             return wide_int_to_tree (type, result);
1045         }
1046       return NULL_TREE;
1047     }
1048
1049   if (real_cst_p (arg))
1050     {
1051       gcc_checking_assert (SCALAR_FLOAT_MODE_P (arg_mode));
1052       if (mode == arg_mode)
1053         {
1054           /* real -> real.  */
1055           REAL_VALUE_TYPE result;
1056           if (fold_const_call_ss (&result, fn, TREE_REAL_CST_PTR (arg),
1057                                   REAL_MODE_FORMAT (mode)))
1058             return build_real (type, result);
1059         }
1060       else if (COMPLEX_MODE_P (mode)
1061                && GET_MODE_INNER (mode) == arg_mode)
1062         {
1063           /* real -> complex real.  */
1064           REAL_VALUE_TYPE result_real, result_imag;
1065           if (fold_const_call_cs (&result_real, &result_imag, fn,
1066                                   TREE_REAL_CST_PTR (arg),
1067                                   REAL_MODE_FORMAT (arg_mode)))
1068             return build_complex (type,
1069                                   build_real (TREE_TYPE (type), result_real),
1070                                   build_real (TREE_TYPE (type), result_imag));
1071         }
1072       else if (INTEGRAL_TYPE_P (type))
1073         {
1074           /* real -> int.  */
1075           wide_int result;
1076           if (fold_const_call_ss (&result, fn,
1077                                   TREE_REAL_CST_PTR (arg),
1078                                   TYPE_PRECISION (type),
1079                                   REAL_MODE_FORMAT (arg_mode)))
1080             return wide_int_to_tree (type, result);
1081         }
1082       return NULL_TREE;
1083     }
1084
1085   if (complex_cst_p (arg))
1086     {
1087       gcc_checking_assert (COMPLEX_MODE_P (arg_mode));
1088       machine_mode inner_mode = GET_MODE_INNER (arg_mode);
1089       tree argr = TREE_REALPART (arg);
1090       tree argi = TREE_IMAGPART (arg);
1091       if (mode == arg_mode
1092           && real_cst_p (argr)
1093           && real_cst_p (argi))
1094         {
1095           /* complex real -> complex real.  */
1096           REAL_VALUE_TYPE result_real, result_imag;
1097           if (fold_const_call_cc (&result_real, &result_imag, fn,
1098                                   TREE_REAL_CST_PTR (argr),
1099                                   TREE_REAL_CST_PTR (argi),
1100                                   REAL_MODE_FORMAT (inner_mode)))
1101             return build_complex (type,
1102                                   build_real (TREE_TYPE (type), result_real),
1103                                   build_real (TREE_TYPE (type), result_imag));
1104         }
1105       if (mode == inner_mode
1106           && real_cst_p (argr)
1107           && real_cst_p (argi))
1108         {
1109           /* complex real -> real.  */
1110           REAL_VALUE_TYPE result;
1111           if (fold_const_call_sc (&result, fn,
1112                                   TREE_REAL_CST_PTR (argr),
1113                                   TREE_REAL_CST_PTR (argi),
1114                                   REAL_MODE_FORMAT (inner_mode)))
1115             return build_real (type, result);
1116         }
1117       return NULL_TREE;
1118     }
1119
1120   return NULL_TREE;
1121 }
1122
1123 /* Try to fold FN (ARG) to a constant.  Return the constant on success,
1124    otherwise return null.  TYPE is the type of the return value.  */
1125
1126 tree
1127 fold_const_call (combined_fn fn, tree type, tree arg)
1128 {
1129   switch (fn)
1130     {
1131     case CFN_BUILT_IN_STRLEN:
1132       if (const char *str = c_getstr (arg))
1133         return build_int_cst (type, strlen (str));
1134       return NULL_TREE;
1135
1136     CASE_CFN_NAN:
1137     CASE_FLT_FN_FLOATN_NX (CFN_BUILT_IN_NAN):
1138     case CFN_BUILT_IN_NAND32:
1139     case CFN_BUILT_IN_NAND64:
1140     case CFN_BUILT_IN_NAND128:
1141       return fold_const_builtin_nan (type, arg, true);
1142
1143     CASE_CFN_NANS:
1144     CASE_FLT_FN_FLOATN_NX (CFN_BUILT_IN_NANS):
1145       return fold_const_builtin_nan (type, arg, false);
1146
1147     default:
1148       return fold_const_call_1 (fn, type, arg);
1149     }
1150 }
1151
1152 /* Try to evaluate:
1153
1154       *RESULT = FN (*ARG0, *ARG1)
1155
1156    in format FORMAT.  Return true on success.  */
1157
1158 static bool
1159 fold_const_call_sss (real_value *result, combined_fn fn,
1160                      const real_value *arg0, const real_value *arg1,
1161                      const real_format *format)
1162 {
1163   switch (fn)
1164     {
1165     CASE_CFN_DREM:
1166     CASE_CFN_REMAINDER:
1167       return do_mpfr_arg2 (result, mpfr_remainder, arg0, arg1, format);
1168
1169     CASE_CFN_ATAN2:
1170       return do_mpfr_arg2 (result, mpfr_atan2, arg0, arg1, format);
1171
1172     CASE_CFN_FDIM:
1173       return do_mpfr_arg2 (result, mpfr_dim, arg0, arg1, format);
1174
1175     CASE_CFN_HYPOT:
1176       return do_mpfr_arg2 (result, mpfr_hypot, arg0, arg1, format);
1177
1178     CASE_CFN_COPYSIGN:
1179       *result = *arg0;
1180       real_copysign (result, arg1);
1181       return true;
1182
1183     CASE_CFN_FMIN:
1184       return do_mpfr_arg2 (result, mpfr_min, arg0, arg1, format);
1185
1186     CASE_CFN_FMAX:
1187       return do_mpfr_arg2 (result, mpfr_max, arg0, arg1, format);
1188
1189     CASE_CFN_POW:
1190       return fold_const_pow (result, arg0, arg1, format);
1191
1192     default:
1193       return false;
1194     }
1195 }
1196
1197 /* Try to evaluate:
1198
1199       *RESULT = FN (*ARG0, ARG1)
1200
1201    where FORMAT is the format of *RESULT and *ARG0.  Return true on
1202    success.  */
1203
1204 static bool
1205 fold_const_call_sss (real_value *result, combined_fn fn,
1206                      const real_value *arg0, const wide_int_ref &arg1,
1207                      const real_format *format)
1208 {
1209   switch (fn)
1210     {
1211     CASE_CFN_LDEXP:
1212       return fold_const_builtin_load_exponent (result, arg0, arg1, format);
1213
1214     CASE_CFN_SCALBN:
1215     CASE_CFN_SCALBLN:
1216       return (format->b == 2
1217               && fold_const_builtin_load_exponent (result, arg0, arg1,
1218                                                    format));
1219
1220     CASE_CFN_POWI:
1221       /* Avoid the folding if flag_signaling_nans is on and
1222          operand is a signaling NaN.  */
1223       if (!flag_unsafe_math_optimizations
1224           && flag_signaling_nans
1225           && REAL_VALUE_ISSIGNALING_NAN (*arg0))
1226         return false;
1227
1228       real_powi (result, format, arg0, arg1.to_shwi ());
1229       return true;
1230
1231     default:
1232       return false;
1233     }
1234 }
1235
1236 /* Try to evaluate:
1237
1238       *RESULT = FN (ARG0, *ARG1)
1239
1240    where FORMAT is the format of *RESULT and *ARG1.  Return true on
1241    success.  */
1242
1243 static bool
1244 fold_const_call_sss (real_value *result, combined_fn fn,
1245                      const wide_int_ref &arg0, const real_value *arg1,
1246                      const real_format *format)
1247 {
1248   switch (fn)
1249     {
1250     CASE_CFN_JN:
1251       return do_mpfr_arg2 (result, mpfr_jn, arg0, arg1, format);
1252
1253     CASE_CFN_YN:
1254       return (real_compare (GT_EXPR, arg1, &dconst0)
1255               && do_mpfr_arg2 (result, mpfr_yn, arg0, arg1, format));
1256
1257     default:
1258       return false;
1259     }
1260 }
1261
1262 /* Try to evaluate:
1263
1264       RESULT = fn (ARG0, ARG1)
1265
1266    where FORMAT is the format of the real and imaginary parts of RESULT
1267    (RESULT_REAL and RESULT_IMAG), of ARG0 (ARG0_REAL and ARG0_IMAG)
1268    and of ARG1 (ARG1_REAL and ARG1_IMAG).  Return true on success.  */
1269
1270 static bool
1271 fold_const_call_ccc (real_value *result_real, real_value *result_imag,
1272                      combined_fn fn, const real_value *arg0_real,
1273                      const real_value *arg0_imag, const real_value *arg1_real,
1274                      const real_value *arg1_imag, const real_format *format)
1275 {
1276   switch (fn)
1277     {
1278     CASE_CFN_CPOW:
1279       return do_mpc_arg2 (result_real, result_imag, mpc_pow,
1280                           arg0_real, arg0_imag, arg1_real, arg1_imag, format);
1281
1282     default:
1283       return false;
1284     }
1285 }
1286
1287 /* Subroutine of fold_const_call, with the same interface.  Handle cases
1288    where the arguments and result are numerical.  */
1289
1290 static tree
1291 fold_const_call_1 (combined_fn fn, tree type, tree arg0, tree arg1)
1292 {
1293   machine_mode mode = TYPE_MODE (type);
1294   machine_mode arg0_mode = TYPE_MODE (TREE_TYPE (arg0));
1295   machine_mode arg1_mode = TYPE_MODE (TREE_TYPE (arg1));
1296
1297   if (arg0_mode == arg1_mode
1298       && real_cst_p (arg0)
1299       && real_cst_p (arg1))
1300     {
1301       gcc_checking_assert (SCALAR_FLOAT_MODE_P (arg0_mode));
1302       if (mode == arg0_mode)
1303         {
1304           /* real, real -> real.  */
1305           REAL_VALUE_TYPE result;
1306           if (fold_const_call_sss (&result, fn, TREE_REAL_CST_PTR (arg0),
1307                                    TREE_REAL_CST_PTR (arg1),
1308                                    REAL_MODE_FORMAT (mode)))
1309             return build_real (type, result);
1310         }
1311       return NULL_TREE;
1312     }
1313
1314   if (real_cst_p (arg0)
1315       && integer_cst_p (arg1))
1316     {
1317       gcc_checking_assert (SCALAR_FLOAT_MODE_P (arg0_mode));
1318       if (mode == arg0_mode)
1319         {
1320           /* real, int -> real.  */
1321           REAL_VALUE_TYPE result;
1322           if (fold_const_call_sss (&result, fn, TREE_REAL_CST_PTR (arg0),
1323                                    arg1, REAL_MODE_FORMAT (mode)))
1324             return build_real (type, result);
1325         }
1326       return NULL_TREE;
1327     }
1328
1329   if (integer_cst_p (arg0)
1330       && real_cst_p (arg1))
1331     {
1332       gcc_checking_assert (SCALAR_FLOAT_MODE_P (arg1_mode));
1333       if (mode == arg1_mode)
1334         {
1335           /* int, real -> real.  */
1336           REAL_VALUE_TYPE result;
1337           if (fold_const_call_sss (&result, fn, arg0,
1338                                    TREE_REAL_CST_PTR (arg1),
1339                                    REAL_MODE_FORMAT (mode)))
1340             return build_real (type, result);
1341         }
1342       return NULL_TREE;
1343     }
1344
1345   if (arg0_mode == arg1_mode
1346       && complex_cst_p (arg0)
1347       && complex_cst_p (arg1))
1348     {
1349       gcc_checking_assert (COMPLEX_MODE_P (arg0_mode));
1350       machine_mode inner_mode = GET_MODE_INNER (arg0_mode);
1351       tree arg0r = TREE_REALPART (arg0);
1352       tree arg0i = TREE_IMAGPART (arg0);
1353       tree arg1r = TREE_REALPART (arg1);
1354       tree arg1i = TREE_IMAGPART (arg1);
1355       if (mode == arg0_mode
1356           && real_cst_p (arg0r)
1357           && real_cst_p (arg0i)
1358           && real_cst_p (arg1r)
1359           && real_cst_p (arg1i))
1360         {
1361           /* complex real, complex real -> complex real.  */
1362           REAL_VALUE_TYPE result_real, result_imag;
1363           if (fold_const_call_ccc (&result_real, &result_imag, fn,
1364                                    TREE_REAL_CST_PTR (arg0r),
1365                                    TREE_REAL_CST_PTR (arg0i),
1366                                    TREE_REAL_CST_PTR (arg1r),
1367                                    TREE_REAL_CST_PTR (arg1i),
1368                                    REAL_MODE_FORMAT (inner_mode)))
1369             return build_complex (type,
1370                                   build_real (TREE_TYPE (type), result_real),
1371                                   build_real (TREE_TYPE (type), result_imag));
1372         }
1373       return NULL_TREE;
1374     }
1375
1376   return NULL_TREE;
1377 }
1378
1379 /* Try to fold FN (ARG0, ARG1) to a constant.  Return the constant on success,
1380    otherwise return null.  TYPE is the type of the return value.  */
1381
1382 tree
1383 fold_const_call (combined_fn fn, tree type, tree arg0, tree arg1)
1384 {
1385   const char *p0, *p1;
1386   switch (fn)
1387     {
1388     case CFN_BUILT_IN_STRSPN:
1389       if ((p0 = c_getstr (arg0)) && (p1 = c_getstr (arg1)))
1390         return build_int_cst (type, strspn (p0, p1));
1391       return NULL_TREE;
1392
1393     case CFN_BUILT_IN_STRCSPN:
1394       if ((p0 = c_getstr (arg0)) && (p1 = c_getstr (arg1)))
1395         return build_int_cst (type, strcspn (p0, p1));
1396       return NULL_TREE;
1397
1398     case CFN_BUILT_IN_STRCMP:
1399       if ((p0 = c_getstr (arg0)) && (p1 = c_getstr (arg1)))
1400         return build_cmp_result (type, strcmp (p0, p1));
1401       return NULL_TREE;
1402
1403     case CFN_BUILT_IN_STRCASECMP:
1404       if ((p0 = c_getstr (arg0)) && (p1 = c_getstr (arg1)))
1405         {
1406           int r = strcmp (p0, p1);
1407           if (r == 0)
1408             return build_cmp_result (type, r);
1409         }
1410       return NULL_TREE;
1411
1412     default:
1413       return fold_const_call_1 (fn, type, arg0, arg1);
1414     }
1415 }
1416
1417 /* Try to evaluate:
1418
1419       *RESULT = FN (*ARG0, *ARG1, *ARG2)
1420
1421    in format FORMAT.  Return true on success.  */
1422
1423 static bool
1424 fold_const_call_ssss (real_value *result, combined_fn fn,
1425                       const real_value *arg0, const real_value *arg1,
1426                       const real_value *arg2, const real_format *format)
1427 {
1428   switch (fn)
1429     {
1430     CASE_CFN_FMA:
1431       return do_mpfr_arg3 (result, mpfr_fma, arg0, arg1, arg2, format);
1432
1433     default:
1434       return false;
1435     }
1436 }
1437
1438 /* Subroutine of fold_const_call, with the same interface.  Handle cases
1439    where the arguments and result are numerical.  */
1440
1441 static tree
1442 fold_const_call_1 (combined_fn fn, tree type, tree arg0, tree arg1, tree arg2)
1443 {
1444   machine_mode mode = TYPE_MODE (type);
1445   machine_mode arg0_mode = TYPE_MODE (TREE_TYPE (arg0));
1446   machine_mode arg1_mode = TYPE_MODE (TREE_TYPE (arg1));
1447   machine_mode arg2_mode = TYPE_MODE (TREE_TYPE (arg2));
1448
1449   if (arg0_mode == arg1_mode
1450       && arg0_mode == arg2_mode
1451       && real_cst_p (arg0)
1452       && real_cst_p (arg1)
1453       && real_cst_p (arg2))
1454     {
1455       gcc_checking_assert (SCALAR_FLOAT_MODE_P (arg0_mode));
1456       if (mode == arg0_mode)
1457         {
1458           /* real, real, real -> real.  */
1459           REAL_VALUE_TYPE result;
1460           if (fold_const_call_ssss (&result, fn, TREE_REAL_CST_PTR (arg0),
1461                                     TREE_REAL_CST_PTR (arg1),
1462                                     TREE_REAL_CST_PTR (arg2),
1463                                     REAL_MODE_FORMAT (mode)))
1464             return build_real (type, result);
1465         }
1466       return NULL_TREE;
1467     }
1468
1469   switch (fn)
1470     {
1471     case CFN_BUILT_IN_MEMCHR:
1472       {
1473         char c;
1474         if (integer_zerop (arg2)
1475             && !TREE_SIDE_EFFECTS (arg0)
1476             && !TREE_SIDE_EFFECTS (arg1))
1477           return build_int_cst (type, 0);
1478
1479         if (!tree_fits_uhwi_p (arg2) || !target_char_cst_p (arg1, &c))
1480           return NULL_TREE;
1481
1482         unsigned HOST_WIDE_INT length = tree_to_uhwi (arg2);
1483         unsigned HOST_WIDE_INT string_length;
1484         const char *p1 = c_getstr (arg0, &string_length);
1485         if (p1)
1486           {
1487             const char *r
1488               = (const char *)memchr (p1, c, MIN (length, string_length));
1489             if (r == NULL && length <= string_length)
1490               return build_int_cst (type, 0);
1491           }
1492
1493         break;
1494       }
1495     default:
1496       break;
1497     }
1498
1499   return NULL_TREE;
1500 }
1501
1502 /* Try to fold FN (ARG0, ARG1, ARG2) to a constant.  Return the constant on
1503    success, otherwise return null.  TYPE is the type of the return value.  */
1504
1505 tree
1506 fold_const_call (combined_fn fn, tree type, tree arg0, tree arg1, tree arg2)
1507 {
1508   const char *p0, *p1;
1509   unsigned HOST_WIDE_INT s0, s1;
1510   size_t s2 = 0;
1511   switch (fn)
1512     {
1513     case CFN_BUILT_IN_STRNCMP:
1514       {
1515         bool const_size_p = host_size_t_cst_p (arg2, &s2);
1516         if (const_size_p && s2 == 0
1517             && !TREE_SIDE_EFFECTS (arg0)
1518             && !TREE_SIDE_EFFECTS (arg1))
1519           return build_int_cst (type, 0);
1520         else if (const_size_p
1521                  && (p0 = c_getstr (arg0))
1522                  && (p1 = c_getstr (arg1)))
1523           return build_int_cst (type, strncmp (p0, p1, s2));
1524         return NULL_TREE;
1525       }
1526     case CFN_BUILT_IN_STRNCASECMP:
1527       {
1528         bool const_size_p = host_size_t_cst_p (arg2, &s2);
1529         if (const_size_p && s2 == 0
1530             && !TREE_SIDE_EFFECTS (arg0)
1531             && !TREE_SIDE_EFFECTS (arg1))
1532           return build_int_cst (type, 0);
1533         else if (const_size_p
1534                  && (p0 = c_getstr (arg0))
1535                  && (p1 = c_getstr (arg1))
1536                  && strncmp (p0, p1, s2) == 0)
1537           return build_int_cst (type, 0);
1538         return NULL_TREE;
1539       }
1540     case CFN_BUILT_IN_BCMP:
1541     case CFN_BUILT_IN_MEMCMP:
1542       if ((p0 = c_getstr (arg0, &s0))
1543           && (p1 = c_getstr (arg1, &s1))
1544           && host_size_t_cst_p (arg2, &s2)
1545           && s2 <= s0
1546           && s2 <= s1)
1547         return build_cmp_result (type, memcmp (p0, p1, s2));
1548       return NULL_TREE;
1549
1550     default:
1551       return fold_const_call_1 (fn, type, arg0, arg1, arg2);
1552     }
1553 }
1554
1555 /* Fold a fma operation with arguments ARG[012].  */
1556
1557 tree
1558 fold_fma (location_t, tree type, tree arg0, tree arg1, tree arg2)
1559 {
1560   REAL_VALUE_TYPE result;
1561   if (real_cst_p (arg0)
1562       && real_cst_p (arg1)
1563       && real_cst_p (arg2)
1564       && do_mpfr_arg3 (&result, mpfr_fma, TREE_REAL_CST_PTR (arg0),
1565                        TREE_REAL_CST_PTR (arg1), TREE_REAL_CST_PTR (arg2),
1566                        REAL_MODE_FORMAT (TYPE_MODE (type))))
1567     return build_real (type, result);
1568
1569   return NULL_TREE;
1570 }