Move constant folds for maths functions to new file

The new routines operate on the built-in enum rather than on tree decls.
The idea is to extend this to handle internal functions too, with a
combined enum for both.

The patch also moves fold_fma too, with the same prototype.  The long-term
plan is to replace FMA_EXPR with an internal function, for consistency
with the way that things like SQRT will be handled.

Tested on x86_64-linux-gnu, arm-linux-gnueabi and aarch64-linux-gnu.

gcc/
	* builtins.h (fold_fma): Move to fold-const-call.h.
	* builtins.c: Include fold-const-call.h.
	(mathfn_built_in_2): New function, split out from...
	(mathfn_built_in_1): ...here.
	(do_real_to_int_conversion, fold_const_builtin_pow)
	(fold_const_builtin_logb, fold_const_builtin_significand)
	(fold_const_builtin_load_exponent, do_mpfr_arg1, do_mpfr_arg2)
	(do_mpfr_arg3, do_mpfr_sincos, do_mpfr_bessel_n, do_mpc_arg1): Delete.
	(fold_builtin_sincos): Use fold_const_call to handle constants.
	(fold_builtin_1, fold_builtin_2, fold_builtin_3): Add explicit
	checks for ERROR_MARK.  Use fold_const_call to handle constant
	folds for math functions.
	(fold_fma): Move to fold-const-call.c.
	* fold-const.c: Include fold-const-call.h.
	* Makefile.in (OBJS): Add fold-const-call.o.
	(PLUGIN_HEADERS): Add fold-const-call.h.
	* realmpfr.h (real_from_mpfr): Allow the format to be specified
	directly.
	* realmpfr.c (real_from_mpfr): Likewise.
	* fold-const-call.h, fold-const-call.c: New files.

From-SVN: r229669

1 files changed, 1259 insertions, 0 deletions

diff --git a/gcc/fold-const-call.c b/gcc/fold-const-call.c
new file mode 100644
index 00000000000..5af2c635313
--- /dev/null
+++ b/gcc/fold-const-call.c
@@ -0,0 +1,1259 @@
+/* Constant folding for calls to built-in and internal functions.
+   Copyright (C) 1988-2015 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 3, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "realmpfr.h"
+#include "tree.h"
+#include "stor-layout.h"
+#include "options.h"
+#include "fold-const-call.h"
+
+/* Functions that test for certain constant types, abstracting away the
+   decision about whether to check for overflow.  */
+
+static inline bool
+integer_cst_p (tree t)
+{
+  return TREE_CODE (t) == INTEGER_CST && !TREE_OVERFLOW (t);
+}
+
+static inline bool
+real_cst_p (tree t)
+{
+  return TREE_CODE (t) == REAL_CST && !TREE_OVERFLOW (t);
+}
+
+static inline bool
+complex_cst_p (tree t)
+{
+  return TREE_CODE (t) == COMPLEX_CST;
+}
+
+/* M is the result of trying to constant-fold an expression (starting
+   with clear MPFR flags) and INEXACT says whether the result in M is
+   exact or inexact.  Return true if M can be used as a constant-folded
+   result in format FORMAT, storing the value in *RESULT if so.  */
+
+static bool
+do_mpfr_ckconv (real_value *result, mpfr_srcptr m, bool inexact,
+		const real_format *format)
+{
+  /* Proceed iff we get a normal number, i.e. not NaN or Inf and no
+     overflow/underflow occurred.  If -frounding-math, proceed iff the
+     result of calling FUNC was exact.  */
+  if (!mpfr_number_p (m)
+      || mpfr_overflow_p ()
+      || mpfr_underflow_p ()
+      || (flag_rounding_math && inexact))
+    return false;
+
+  REAL_VALUE_TYPE tmp;
+  real_from_mpfr (&tmp, m, format, GMP_RNDN);
+
+  /* Proceed iff GCC's REAL_VALUE_TYPE can hold the MPFR values.
+     If the REAL_VALUE_TYPE is zero but the mpft_t is not, then we
+     underflowed in the conversion.  */
+  if (!real_isfinite (&tmp)
+      || ((tmp.cl == rvc_zero) != (mpfr_zero_p (m) != 0)))
+    return false;
+
+  real_convert (result, format, &tmp);
+  return real_identical (result, &tmp);
+}
+
+/* Try to evaluate:
+
+      *RESULT = f (*ARG)
+
+   in format FORMAT, given that FUNC is the MPFR implementation of f.
+   Return true on success.  */
+
+static bool
+do_mpfr_arg1 (real_value *result,
+	      int (*func) (mpfr_ptr, mpfr_srcptr, mpfr_rnd_t),
+	      const real_value *arg, const real_format *format)
+{
+  /* To proceed, MPFR must exactly represent the target floating point
+     format, which only happens when the target base equals two.  */
+  if (format->b != 2 || !real_isfinite (arg))
+    return false;
+
+  int prec = format->p;
+  mp_rnd_t rnd = format->round_towards_zero ? GMP_RNDZ : GMP_RNDN;
+  mpfr_t m;
+
+  mpfr_init2 (m, prec);
+  mpfr_from_real (m, arg, GMP_RNDN);
+  mpfr_clear_flags ();
+  bool inexact = func (m, m, rnd);
+  bool ok = do_mpfr_ckconv (result, m, inexact, format);
+  mpfr_clear (m);
+
+  return ok;
+}
+
+/* Try to evaluate:
+
+      *RESULT_SIN = sin (*ARG);
+      *RESULT_COS = cos (*ARG);
+
+   for format FORMAT.  Return true on success.  */
+
+static bool
+do_mpfr_sincos (real_value *result_sin, real_value *result_cos,
+		const real_value *arg, const real_format *format)
+{
+  /* To proceed, MPFR must exactly represent the target floating point
+     format, which only happens when the target base equals two.  */
+  if (format->b != 2 || !real_isfinite (arg))
+    return false;
+
+  int prec = format->p;
+  mp_rnd_t rnd = format->round_towards_zero ? GMP_RNDZ : GMP_RNDN;
+  mpfr_t m, ms, mc;
+
+  mpfr_inits2 (prec, m, ms, mc, NULL);
+  mpfr_from_real (m, arg, GMP_RNDN);
+  mpfr_clear_flags ();
+  bool inexact = mpfr_sin_cos (ms, mc, m, rnd);
+  bool ok = (do_mpfr_ckconv (result_sin, ms, inexact, format)
+	     && do_mpfr_ckconv (result_cos, mc, inexact, format));
+  mpfr_clears (m, ms, mc, NULL);
+
+  return ok;
+}
+
+/* Try to evaluate:
+
+      *RESULT = f (*ARG0, *ARG1)
+
+   in format FORMAT, given that FUNC is the MPFR implementation of f.
+   Return true on success.  */
+
+static bool
+do_mpfr_arg2 (real_value *result,
+	      int (*func) (mpfr_ptr, mpfr_srcptr, mpfr_srcptr, mpfr_rnd_t),
+	      const real_value *arg0, const real_value *arg1,
+	      const real_format *format)
+{
+  /* To proceed, MPFR must exactly represent the target floating point
+     format, which only happens when the target base equals two.  */
+  if (format->b != 2 || !real_isfinite (arg0) || !real_isfinite (arg1))
+    return false;
+
+  int prec = format->p;
+  mp_rnd_t rnd = format->round_towards_zero ? GMP_RNDZ : GMP_RNDN;
+  mpfr_t m0, m1;
+
+  mpfr_inits2 (prec, m0, m1, NULL);
+  mpfr_from_real (m0, arg0, GMP_RNDN);
+  mpfr_from_real (m1, arg1, GMP_RNDN);
+  mpfr_clear_flags ();
+  bool inexact = func (m0, m0, m1, rnd);
+  bool ok = do_mpfr_ckconv (result, m0, inexact, format);
+  mpfr_clears (m0, m1, NULL);
+
+  return ok;
+}
+
+/* Try to evaluate:
+
+      *RESULT = f (ARG0, *ARG1)
+
+   in format FORMAT, given that FUNC is the MPFR implementation of f.
+   Return true on success.  */
+
+static bool
+do_mpfr_arg2 (real_value *result,
+	      int (*func) (mpfr_ptr, long, mpfr_srcptr, mp_rnd_t),
+	      const wide_int_ref &arg0, const real_value *arg1,
+	      const real_format *format)
+{
+  if (format->b != 2 || !real_isfinite (arg1))
+    return false;
+
+  int prec = format->p;
+  mp_rnd_t rnd = format->round_towards_zero ? GMP_RNDZ : GMP_RNDN;
+  mpfr_t m;
+
+  mpfr_init2 (m, prec);
+  mpfr_from_real (m, arg1, GMP_RNDN);
+  mpfr_clear_flags ();
+  bool inexact = func (m, arg0.to_shwi (), m, rnd);
+  bool ok = do_mpfr_ckconv (result, m, inexact, format);
+  mpfr_clear (m);
+
+  return ok;
+}
+
+/* Try to evaluate:
+
+      *RESULT = f (*ARG0, *ARG1, *ARG2)
+
+   in format FORMAT, given that FUNC is the MPFR implementation of f.
+   Return true on success.  */
+
+static bool
+do_mpfr_arg3 (real_value *result,
+	      int (*func) (mpfr_ptr, mpfr_srcptr, mpfr_srcptr,
+			   mpfr_srcptr, mpfr_rnd_t),
+	      const real_value *arg0, const real_value *arg1,
+	      const real_value *arg2, const real_format *format)
+{
+  /* To proceed, MPFR must exactly represent the target floating point
+     format, which only happens when the target base equals two.  */
+  if (format->b != 2
+      || !real_isfinite (arg0)
+      || !real_isfinite (arg1)
+      || !real_isfinite (arg2))
+    return false;
+
+  int prec = format->p;
+  mp_rnd_t rnd = format->round_towards_zero ? GMP_RNDZ : GMP_RNDN;
+  mpfr_t m0, m1, m2;
+
+  mpfr_inits2 (prec, m0, m1, m2, NULL);
+  mpfr_from_real (m0, arg0, GMP_RNDN);
+  mpfr_from_real (m1, arg1, GMP_RNDN);
+  mpfr_from_real (m2, arg2, GMP_RNDN);
+  mpfr_clear_flags ();
+  bool inexact = func (m0, m0, m1, m2, rnd);
+  bool ok = do_mpfr_ckconv (result, m0, inexact, format);
+  mpfr_clears (m0, m1, m2, NULL);
+
+  return ok;
+}
+
+/* M is the result of trying to constant-fold an expression (starting
+   with clear MPFR flags) and INEXACT says whether the result in M is
+   exact or inexact.  Return true if M can be used as a constant-folded
+   result in which the real and imaginary parts have format FORMAT.
+   Store those parts in *RESULT_REAL and *RESULT_IMAG if so.  */
+
+static bool
+do_mpc_ckconv (real_value *result_real, real_value *result_imag,
+	       mpc_srcptr m, bool inexact, const real_format *format)
+{
+  /* Proceed iff we get a normal number, i.e. not NaN or Inf and no
+     overflow/underflow occurred.  If -frounding-math, proceed iff the
+     result of calling FUNC was exact.  */
+  if (!mpfr_number_p (mpc_realref (m))
+      || !mpfr_number_p (mpc_imagref (m))
+      || mpfr_overflow_p ()
+      || mpfr_underflow_p ()
+      || (flag_rounding_math && inexact))
+    return false;
+
+  REAL_VALUE_TYPE tmp_real, tmp_imag;
+  real_from_mpfr (&tmp_real, mpc_realref (m), format, GMP_RNDN);
+  real_from_mpfr (&tmp_imag, mpc_imagref (m), format, GMP_RNDN);
+
+  /* Proceed iff GCC's REAL_VALUE_TYPE can hold the MPFR values.
+     If the REAL_VALUE_TYPE is zero but the mpft_t is not, then we
+     underflowed in the conversion.  */
+  if (!real_isfinite (&tmp_real)
+      || !real_isfinite (&tmp_imag)
+      || (tmp_real.cl == rvc_zero) != (mpfr_zero_p (mpc_realref (m)) != 0)
+      || (tmp_imag.cl == rvc_zero) != (mpfr_zero_p (mpc_imagref (m)) != 0))
+    return false;
+
+  real_convert (result_real, format, &tmp_real);
+  real_convert (result_imag, format, &tmp_imag);
+
+  return (real_identical (result_real, &tmp_real)
+	  && real_identical (result_imag, &tmp_imag));
+}
+
+/* Try to evaluate:
+
+      RESULT = f (ARG)
+
+   in format FORMAT, given that FUNC is the mpc implementation of f.
+   Return true on success.  Both RESULT and ARG are represented as
+   real and imaginary pairs.  */
+
+static bool
+do_mpc_arg1 (real_value *result_real, real_value *result_imag,
+	     int (*func) (mpc_ptr, mpc_srcptr, mpc_rnd_t),
+	     const real_value *arg_real, const real_value *arg_imag,
+	     const real_format *format)
+{
+  /* To proceed, MPFR must exactly represent the target floating point
+     format, which only happens when the target base equals two.  */
+  if (format->b != 2
+      || !real_isfinite (arg_real)
+      || !real_isfinite (arg_imag))
+    return false;
+
+  int prec = format->p;
+  mpc_rnd_t crnd = format->round_towards_zero ? MPC_RNDZZ : MPC_RNDNN;
+  mpc_t m;
+
+  mpc_init2 (m, prec);
+  mpfr_from_real (mpc_realref (m), arg_real, GMP_RNDN);
+  mpfr_from_real (mpc_imagref (m), arg_imag, GMP_RNDN);
+  mpfr_clear_flags ();
+  bool inexact = func (m, m, crnd);
+  bool ok = do_mpc_ckconv (result_real, result_imag, m, inexact, format);
+  mpc_clear (m);
+
+  return ok;
+}
+
+/* Try to evaluate:
+
+      RESULT = f (ARG0, ARG1)
+
+   in format FORMAT, given that FUNC is the mpc implementation of f.
+   Return true on success.  RESULT, ARG0 and ARG1 are represented as
+   real and imaginary pairs.  */
+
+static bool
+do_mpc_arg2 (real_value *result_real, real_value *result_imag,
+	     int (*func)(mpc_ptr, mpc_srcptr, mpc_srcptr, mpc_rnd_t),
+	     const real_value *arg0_real, const real_value *arg0_imag,
+	     const real_value *arg1_real, const real_value *arg1_imag,
+	     const real_format *format)
+{
+  if (!real_isfinite (arg0_real)
+      || !real_isfinite (arg0_imag)
+      || !real_isfinite (arg1_real)
+      || !real_isfinite (arg1_imag))
+    return false;
+
+  int prec = format->p;
+  mpc_rnd_t crnd = format->round_towards_zero ? MPC_RNDZZ : MPC_RNDNN;
+  mpc_t m0, m1;
+
+  mpc_init2 (m0, prec);
+  mpc_init2 (m1, prec);
+  mpfr_from_real (mpc_realref (m0), arg0_real, GMP_RNDN);
+  mpfr_from_real (mpc_imagref (m0), arg0_imag, GMP_RNDN);
+  mpfr_from_real (mpc_realref (m1), arg1_real, GMP_RNDN);
+  mpfr_from_real (mpc_imagref (m1), arg1_imag, GMP_RNDN);
+  mpfr_clear_flags ();
+  bool inexact = func (m0, m0, m1, crnd);
+  bool ok = do_mpc_ckconv (result_real, result_imag, m0, inexact, format);
+  mpc_clear (m0);
+  mpc_clear (m1);
+
+  return ok;
+}
+
+/* Try to evaluate:
+
+      *RESULT = logb (*ARG)
+
+   in format FORMAT.  Return true on success.  */
+
+static bool
+fold_const_logb (real_value *result, const real_value *arg,
+		 const real_format *format)
+{
+  switch (arg->cl)
+    {
+    case rvc_nan:
+      /* If arg is +-NaN, then return it.  */
+      *result = *arg;
+      return true;
+
+    case rvc_inf:
+      /* If arg is +-Inf, then return +Inf.  */
+      *result = *arg;
+      result->sign = 0;
+      return true;
+
+    case rvc_zero:
+      /* Zero may set errno and/or raise an exception.  */
+      return false;
+
+    case rvc_normal:
+      /* For normal numbers, proceed iff radix == 2.  In GCC,
+	 normalized significands are in the range [0.5, 1.0).  We
+	 want the exponent as if they were [1.0, 2.0) so get the
+	 exponent and subtract 1.  */
+      if (format->b == 2)
+	{
+	  real_from_integer (result, format, REAL_EXP (arg) - 1, SIGNED);
+	  return true;
+	}
+      return false;
+    }
+  gcc_unreachable ();
+}
+
+/* Try to evaluate:
+
+      *RESULT = significand (*ARG)
+
+   in format FORMAT.  Return true on success.  */
+
+static bool
+fold_const_significand (real_value *result, const real_value *arg,
+			const real_format *format)
+{
+  switch (arg->cl)
+    {
+    case rvc_zero:
+    case rvc_nan:
+    case rvc_inf:
+      /* If arg is +-0, +-Inf or +-NaN, then return it.  */
+      *result = *arg;
+      return true;
+
+    case rvc_normal:
+      /* For normal numbers, proceed iff radix == 2.  */
+      if (format->b == 2)
+	{
+	  *result = *arg;
+	  /* In GCC, normalized significands are in the range [0.5, 1.0).
+	     We want them to be [1.0, 2.0) so set the exponent to 1.  */
+	  SET_REAL_EXP (result, 1);
+	  return true;
+	}
+      return false;
+    }
+  gcc_unreachable ();
+}
+
+/* Try to evaluate:
+
+      *RESULT = f (*ARG)
+
+   where FORMAT is the format of *ARG and PRECISION is the number of
+   significant bits in the result.  Return true on success.  */
+
+static bool
+fold_const_conversion (wide_int *result,
+		       void (*fn) (real_value *, format_helper,
+				   const real_value *),
+		       const real_value *arg, unsigned int precision,
+		       const real_format *format)
+{
+  if (!real_isfinite (arg))
+    return false;
+
+  real_value rounded;
+  fn (&rounded, format, arg);
+
+  bool fail = false;
+  *result = real_to_integer (&rounded, &fail, precision);
+  return !fail;
+}
+
+/* Try to evaluate:
+
+      *RESULT = pow (*ARG0, *ARG1)
+
+   in format FORMAT.  Return true on success.  */
+
+static bool
+fold_const_pow (real_value *result, const real_value *arg0,
+		const real_value *arg1, const real_format *format)
+{
+  if (do_mpfr_arg2 (result, mpfr_pow, arg0, arg1, format))
+    return true;
+
+  /* Check for an integer exponent.  */
+  REAL_VALUE_TYPE cint1;
+  HOST_WIDE_INT n1 = real_to_integer (arg1);
+  real_from_integer (&cint1, VOIDmode, n1, SIGNED);
+  /* Attempt to evaluate pow at compile-time, unless this should
+     raise an exception.  */
+  if (real_identical (arg1, &cint1)
+      && (n1 > 0
+	  || (!flag_trapping_math && !flag_errno_math)
+	  || !real_equal (arg0, &dconst0)))
+    {
+      bool inexact = real_powi (result, format, arg0, n1);
+      if (flag_unsafe_math_optimizations || !inexact)
+	return true;
+    }
+
+  return false;
+}
+
+/* Try to evaluate:
+
+      *RESULT = ldexp (*ARG0, ARG1)
+
+   in format FORMAT.  Return true on success.  */
+
+static bool
+fold_const_builtin_load_exponent (real_value *result, const real_value *arg0,
+				  const wide_int_ref &arg1,
+				  const real_format *format)
+{
+  /* Bound the maximum adjustment to twice the range of the
+     mode's valid exponents.  Use abs to ensure the range is
+     positive as a sanity check.  */
+  int max_exp_adj = 2 * labs (format->emax - format->emin);
+
+  /* The requested adjustment must be inside this range.  This
+     is a preliminary cap to avoid things like overflow, we
+     may still fail to compute the result for other reasons.  */
+  if (wi::les_p (arg1, -max_exp_adj) || wi::ges_p (arg1, max_exp_adj))
+    return false;
+
+  REAL_VALUE_TYPE initial_result;
+  real_ldexp (&initial_result, arg0, arg1.to_shwi ());
+
+  /* Ensure we didn't overflow.  */
+  if (real_isinf (&initial_result))
+    return false;
+
+  /* Only proceed if the target mode can hold the
+     resulting value.  */
+  *result = real_value_truncate (format, initial_result);
+  return real_equal (&initial_result, result);
+}
+
+/* Try to evaluate:
+
+      *RESULT = FN (*ARG)
+
+   in format FORMAT.  Return true on success.  */
+
+static bool
+fold_const_call_ss (real_value *result, built_in_function fn,
+		    const real_value *arg, const real_format *format)
+{
+  switch (fn)
+    {
+    CASE_FLT_FN (BUILT_IN_SQRT):
+      return (real_compare (GE_EXPR, arg, &dconst0)
+	      && do_mpfr_arg1 (result, mpfr_sqrt, arg, format));
+
+    CASE_FLT_FN (BUILT_IN_CBRT):
+      return do_mpfr_arg1 (result, mpfr_cbrt, arg, format);
+
+    CASE_FLT_FN (BUILT_IN_ASIN):
+      return (real_compare (GE_EXPR, arg, &dconstm1)
+	      && real_compare (LE_EXPR, arg, &dconst1)
+	      && do_mpfr_arg1 (result, mpfr_asin, arg, format));
+
+    CASE_FLT_FN (BUILT_IN_ACOS):
+      return (real_compare (GE_EXPR, arg, &dconstm1)
+	      && real_compare (LE_EXPR, arg, &dconst1)
+	      && do_mpfr_arg1 (result, mpfr_acos, arg, format));
+
+    CASE_FLT_FN (BUILT_IN_ATAN):
+      return do_mpfr_arg1 (result, mpfr_atan, arg, format);
+
+    CASE_FLT_FN (BUILT_IN_ASINH):
+      return do_mpfr_arg1 (result, mpfr_asinh, arg, format);
+
+    CASE_FLT_FN (BUILT_IN_ACOSH):
+      return (real_compare (GE_EXPR, arg, &dconst1)
+	      && do_mpfr_arg1 (result, mpfr_acosh, arg, format));
+
+    CASE_FLT_FN (BUILT_IN_ATANH):
+      return (real_compare (GE_EXPR, arg, &dconstm1)
+	      && real_compare (LE_EXPR, arg, &dconst1)
+	      && do_mpfr_arg1 (result, mpfr_atanh, arg, format));
+
+    CASE_FLT_FN (BUILT_IN_SIN):
+      return do_mpfr_arg1 (result, mpfr_sin, arg, format);
+
+    CASE_FLT_FN (BUILT_IN_COS):
+      return do_mpfr_arg1 (result, mpfr_cos, arg, format);
+
+    CASE_FLT_FN (BUILT_IN_TAN):
+      return do_mpfr_arg1 (result, mpfr_tan, arg, format);
+
+    CASE_FLT_FN (BUILT_IN_SINH):
+      return do_mpfr_arg1 (result, mpfr_sinh, arg, format);
+
+    CASE_FLT_FN (BUILT_IN_COSH):
+      return do_mpfr_arg1 (result, mpfr_cosh, arg, format);
+
+    CASE_FLT_FN (BUILT_IN_TANH):
+      return do_mpfr_arg1 (result, mpfr_tanh, arg, format);
+
+    CASE_FLT_FN (BUILT_IN_ERF):
+      return do_mpfr_arg1 (result, mpfr_erf, arg, format);
+
+    CASE_FLT_FN (BUILT_IN_ERFC):
+      return do_mpfr_arg1 (result, mpfr_erfc, arg, format);
+
+    CASE_FLT_FN (BUILT_IN_TGAMMA):
+      return do_mpfr_arg1 (result, mpfr_gamma, arg, format);
+
+    CASE_FLT_FN (BUILT_IN_EXP):
+      return do_mpfr_arg1 (result, mpfr_exp, arg, format);
+
+    CASE_FLT_FN (BUILT_IN_EXP2):
+      return do_mpfr_arg1 (result, mpfr_exp2, arg, format);
+
+    CASE_FLT_FN (BUILT_IN_EXP10):
+    CASE_FLT_FN (BUILT_IN_POW10):
+      return do_mpfr_arg1 (result, mpfr_exp10, arg, format);
+
+    CASE_FLT_FN (BUILT_IN_EXPM1):
+      return do_mpfr_arg1 (result, mpfr_expm1, arg, format);
+
+    CASE_FLT_FN (BUILT_IN_LOG):
+      return (real_compare (GT_EXPR, arg, &dconst0)
+	      && do_mpfr_arg1 (result, mpfr_log, arg, format));
+
+    CASE_FLT_FN (BUILT_IN_LOG2):
+      return (real_compare (GT_EXPR, arg, &dconst0)
+	      && do_mpfr_arg1 (result, mpfr_log2, arg, format));
+
+    CASE_FLT_FN (BUILT_IN_LOG10):
+      return (real_compare (GT_EXPR, arg, &dconst0)
+	      && do_mpfr_arg1 (result, mpfr_log10, arg, format));
+
+    CASE_FLT_FN (BUILT_IN_LOG1P):
+      return (real_compare (GT_EXPR, arg, &dconstm1)
+	      && do_mpfr_arg1 (result, mpfr_log1p, arg, format));
+
+    CASE_FLT_FN (BUILT_IN_J0):
+      return do_mpfr_arg1 (result, mpfr_j0, arg, format);
+
+    CASE_FLT_FN (BUILT_IN_J1):
+      return do_mpfr_arg1 (result, mpfr_j1, arg, format);
+
+    CASE_FLT_FN (BUILT_IN_Y0):
+      return (real_compare (GT_EXPR, arg, &dconst0)
+	      && do_mpfr_arg1 (result, mpfr_y0, arg, format));
+
+    CASE_FLT_FN (BUILT_IN_Y1):
+      return (real_compare (GT_EXPR, arg, &dconst0)
+	      && do_mpfr_arg1 (result, mpfr_y1, arg, format));
+
+    CASE_FLT_FN (BUILT_IN_FLOOR):
+      if (!REAL_VALUE_ISNAN (*arg) || !flag_errno_math)
+	{
+	  real_floor (result, format, arg);
+	  return true;
+	}
+      return false;
+
+    CASE_FLT_FN (BUILT_IN_CEIL):
+      if (!REAL_VALUE_ISNAN (*arg) || !flag_errno_math)
+	{
+	  real_ceil (result, format, arg);
+	  return true;
+	}
+      return false;
+
+    CASE_FLT_FN (BUILT_IN_TRUNC):
+      real_trunc (result, format, arg);
+      return true;
+
+    CASE_FLT_FN (BUILT_IN_ROUND):
+      if (!REAL_VALUE_ISNAN (*arg) || !flag_errno_math)
+	{
+	  real_round (result, format, arg);
+	  return true;
+	}
+      return false;
+
+    CASE_FLT_FN (BUILT_IN_LOGB):
+      return fold_const_logb (result, arg, format);
+
+    CASE_FLT_FN (BUILT_IN_SIGNIFICAND):
+      return fold_const_significand (result, arg, format);
+
+    default:
+      return false;
+    }
+}
+
+/* Try to evaluate:
+
+      *RESULT = FN (*ARG)
+
+   where FORMAT is the format of ARG and PRECISION is the number of
+   significant bits in the result.  Return true on success.  */
+
+static bool
+fold_const_call_ss (wide_int *result, built_in_function fn,
+		    const real_value *arg, unsigned int precision,
+		    const real_format *format)
+{
+  switch (fn)
+    {
+    CASE_FLT_FN (BUILT_IN_SIGNBIT):
+      if (real_isneg (arg))
+	*result = wi::one (precision);
+      else
+	*result = wi::zero (precision);
+      return true;
+
+    CASE_FLT_FN (BUILT_IN_ILOGB):
+      /* For ilogb we don't know FP_ILOGB0, so only handle normal values.
+	 Proceed iff radix == 2.  In GCC, normalized significands are in
+	 the range [0.5, 1.0).  We want the exponent as if they were
+	 [1.0, 2.0) so get the exponent and subtract 1.  */
+      if (arg->cl == rvc_normal && format->b == 2)
+	{
+	  *result = wi::shwi (REAL_EXP (arg) - 1, precision);
+	  return true;
+	}
+      return false;
+
+    CASE_FLT_FN (BUILT_IN_ICEIL):
+    CASE_FLT_FN (BUILT_IN_LCEIL):
+    CASE_FLT_FN (BUILT_IN_LLCEIL):
+      return fold_const_conversion (result, real_ceil, arg,
+				    precision, format);
+
+    CASE_FLT_FN (BUILT_IN_LFLOOR):
+    CASE_FLT_FN (BUILT_IN_IFLOOR):
+    CASE_FLT_FN (BUILT_IN_LLFLOOR):
+      return fold_const_conversion (result, real_floor, arg,
+				    precision, format);
+
+    CASE_FLT_FN (BUILT_IN_IROUND):
+    CASE_FLT_FN (BUILT_IN_LROUND):
+    CASE_FLT_FN (BUILT_IN_LLROUND):
+      return fold_const_conversion (result, real_round, arg,
+				    precision, format);
+
+    CASE_FLT_FN (BUILT_IN_IRINT):
+    CASE_FLT_FN (BUILT_IN_LRINT):
+    CASE_FLT_FN (BUILT_IN_LLRINT):
+      /* Not yet folded to a constant.  */
+      return false;
+
+    default:
+      return false;
+    }
+}
+
+/* Try to evaluate:
+
+      RESULT = FN (*ARG)
+
+   where FORMAT is the format of ARG and of the real and imaginary parts
+   of RESULT, passed as RESULT_REAL and RESULT_IMAG respectively.  Return
+   true on success.  */
+
+static bool
+fold_const_call_cs (real_value *result_real, real_value *result_imag,
+		    built_in_function fn, const real_value *arg,
+		    const real_format *format)
+{
+  switch (fn)
+    {
+    CASE_FLT_FN (BUILT_IN_CEXPI):
+      /* cexpi(x+yi) = cos(x)+sin(y)*i.  */
+      return do_mpfr_sincos (result_imag, result_real, arg, format);
+
+    default:
+      return false;
+    }
+}
+
+/* Try to evaluate:
+
+      *RESULT = fn (ARG)
+
+   where FORMAT is the format of RESULT and of the real and imaginary parts
+   of ARG, passed as ARG_REAL and ARG_IMAG respectively.  Return true on
+   success.  */
+
+static bool
+fold_const_call_sc (real_value *result, built_in_function fn,
+		    const real_value *arg_real, const real_value *arg_imag,
+		    const real_format *format)
+{
+  switch (fn)
+    {
+    CASE_FLT_FN (BUILT_IN_CABS):
+      return do_mpfr_arg2 (result, mpfr_hypot, arg_real, arg_imag, format);
+
+    default:
+      return false;
+    }
+}
+
+/* Try to evaluate:
+
+      RESULT = fn (ARG)
+
+   where FORMAT is the format of the real and imaginary parts of RESULT
+   (RESULT_REAL and RESULT_IMAG) and of ARG (ARG_REAL and ARG_IMAG).
+   Return true on success.  */
+
+static bool
+fold_const_call_cc (real_value *result_real, real_value *result_imag,
+		    built_in_function fn, const real_value *arg_real,
+		    const real_value *arg_imag, const real_format *format)
+{
+  switch (fn)
+    {
+    CASE_FLT_FN (BUILT_IN_CCOS):
+      return do_mpc_arg1 (result_real, result_imag, mpc_cos,
+			  arg_real, arg_imag, format);
+
+    CASE_FLT_FN (BUILT_IN_CCOSH):
+      return do_mpc_arg1 (result_real, result_imag, mpc_cosh,
+			  arg_real, arg_imag, format);
+
+    CASE_FLT_FN (BUILT_IN_CPROJ):
+      if (real_isinf (arg_real) || real_isinf (arg_imag))
+	{
+	  real_inf (result_real);
+	  *result_imag = dconst0;
+	  result_imag->sign = arg_imag->sign;
+	}
+      else
+	{
+	  *result_real = *arg_real;
+	  *result_imag = *arg_imag;
+	}
+      return true;
+
+    CASE_FLT_FN (BUILT_IN_CSIN):
+      return do_mpc_arg1 (result_real, result_imag, mpc_sin,
+			  arg_real, arg_imag, format);
+
+    CASE_FLT_FN (BUILT_IN_CSINH):
+      return do_mpc_arg1 (result_real, result_imag, mpc_sinh,
+			  arg_real, arg_imag, format);
+
+    CASE_FLT_FN (BUILT_IN_CTAN):
+      return do_mpc_arg1 (result_real, result_imag, mpc_tan,
+			  arg_real, arg_imag, format);
+
+    CASE_FLT_FN (BUILT_IN_CTANH):
+      return do_mpc_arg1 (result_real, result_imag, mpc_tanh,
+			  arg_real, arg_imag, format);
+
+    CASE_FLT_FN (BUILT_IN_CLOG):
+      return do_mpc_arg1 (result_real, result_imag, mpc_log,
+			  arg_real, arg_imag, format);
+
+    CASE_FLT_FN (BUILT_IN_CSQRT):
+      return do_mpc_arg1 (result_real, result_imag, mpc_sqrt,
+			  arg_real, arg_imag, format);
+
+    CASE_FLT_FN (BUILT_IN_CASIN):
+      return do_mpc_arg1 (result_real, result_imag, mpc_asin,
+			  arg_real, arg_imag, format);
+
+    CASE_FLT_FN (BUILT_IN_CACOS):
+      return do_mpc_arg1 (result_real, result_imag, mpc_acos,
+			  arg_real, arg_imag, format);
+
+    CASE_FLT_FN (BUILT_IN_CATAN):
+      return do_mpc_arg1 (result_real, result_imag, mpc_atan,
+			  arg_real, arg_imag, format);
+
+    CASE_FLT_FN (BUILT_IN_CASINH):
+      return do_mpc_arg1 (result_real, result_imag, mpc_asinh,
+			  arg_real, arg_imag, format);
+
+    CASE_FLT_FN (BUILT_IN_CACOSH):
+      return do_mpc_arg1 (result_real, result_imag, mpc_acosh,
+			  arg_real, arg_imag, format);
+
+    CASE_FLT_FN (BUILT_IN_CATANH):
+      return do_mpc_arg1 (result_real, result_imag, mpc_atanh,
+			  arg_real, arg_imag, format);
+
+    CASE_FLT_FN (BUILT_IN_CEXP):
+      return do_mpc_arg1 (result_real, result_imag, mpc_exp,
+			  arg_real, arg_imag, format);
+
+    default:
+      return false;
+    }
+}
+
+/* Try to fold FN (ARG) to a constant.  Return the constant on success,
+   otherwise return null.  TYPE is the type of the return value.  */
+
+tree
+fold_const_call (built_in_function fn, tree type, tree arg)
+{
+  machine_mode mode = TYPE_MODE (type);
+  machine_mode arg_mode = TYPE_MODE (TREE_TYPE (arg));
+
+  if (real_cst_p (arg))
+    {
+      gcc_checking_assert (SCALAR_FLOAT_MODE_P (arg_mode));
+      if (mode == arg_mode)
+	{
+	  /* real -> real.  */
+	  REAL_VALUE_TYPE result;
+	  if (fold_const_call_ss (&result, fn, TREE_REAL_CST_PTR (arg),
+				  REAL_MODE_FORMAT (mode)))
+	    return build_real (type, result);
+	}
+      else if (COMPLEX_MODE_P (mode)
+	       && GET_MODE_INNER (mode) == arg_mode)
+	{
+	  /* real -> complex real.  */
+	  REAL_VALUE_TYPE result_real, result_imag;
+	  if (fold_const_call_cs (&result_real, &result_imag, fn,
+				  TREE_REAL_CST_PTR (arg),
+				  REAL_MODE_FORMAT (arg_mode)))
+	    return build_complex (type,
+				  build_real (TREE_TYPE (type), result_real),
+				  build_real (TREE_TYPE (type), result_imag));
+	}
+      else if (INTEGRAL_TYPE_P (type))
+	{
+	  /* real -> int.  */
+	  wide_int result;
+	  if (fold_const_call_ss (&result, fn,
+				  TREE_REAL_CST_PTR (arg),
+				  TYPE_PRECISION (type),
+				  REAL_MODE_FORMAT (arg_mode)))
+	    return wide_int_to_tree (type, result);
+	}
+      return NULL_TREE;
+    }
+
+  if (complex_cst_p (arg))
+    {
+      gcc_checking_assert (COMPLEX_MODE_P (arg_mode));
+      machine_mode inner_mode = GET_MODE_INNER (arg_mode);
+      tree argr = TREE_REALPART (arg);
+      tree argi = TREE_IMAGPART (arg);
+      if (mode == arg_mode
+	  && real_cst_p (argr)
+	  && real_cst_p (argi))
+	{
+	  /* complex real -> complex real.  */
+	  REAL_VALUE_TYPE result_real, result_imag;
+	  if (fold_const_call_cc (&result_real, &result_imag, fn,
+				  TREE_REAL_CST_PTR (argr),
+				  TREE_REAL_CST_PTR (argi),
+				  REAL_MODE_FORMAT (inner_mode)))
+	    return build_complex (type,
+				  build_real (TREE_TYPE (type), result_real),
+				  build_real (TREE_TYPE (type), result_imag));
+	}
+      if (mode == inner_mode
+	  && real_cst_p (argr)
+	  && real_cst_p (argi))
+	{
+	  /* complex real -> real.  */
+	  REAL_VALUE_TYPE result;
+	  if (fold_const_call_sc (&result, fn,
+				  TREE_REAL_CST_PTR (argr),
+				  TREE_REAL_CST_PTR (argi),
+				  REAL_MODE_FORMAT (inner_mode)))
+	    return build_real (type, result);
+	}
+      return NULL_TREE;
+    }
+
+  return NULL_TREE;
+}
+
+/* Try to evaluate:
+
+      *RESULT = FN (*ARG0, *ARG1)
+
+   in format FORMAT.  Return true on success.  */
+
+static bool
+fold_const_call_sss (real_value *result, built_in_function fn,
+		     const real_value *arg0, const real_value *arg1,
+		     const real_format *format)
+{
+  switch (fn)
+    {
+    CASE_FLT_FN (BUILT_IN_DREM):
+    CASE_FLT_FN (BUILT_IN_REMAINDER):
+      return do_mpfr_arg2 (result, mpfr_remainder, arg0, arg1, format);
+
+    CASE_FLT_FN (BUILT_IN_ATAN2):
+      return do_mpfr_arg2 (result, mpfr_atan2, arg0, arg1, format);
+
+    CASE_FLT_FN (BUILT_IN_FDIM):
+      return do_mpfr_arg2 (result, mpfr_dim, arg0, arg1, format);
+
+    CASE_FLT_FN (BUILT_IN_HYPOT):
+      return do_mpfr_arg2 (result, mpfr_hypot, arg0, arg1, format);
+
+    CASE_FLT_FN (BUILT_IN_COPYSIGN):
+      *result = *arg0;
+      real_copysign (result, arg1);
+      return true;
+
+    CASE_FLT_FN (BUILT_IN_FMIN):
+      return do_mpfr_arg2 (result, mpfr_min, arg0, arg1, format);
+
+    CASE_FLT_FN (BUILT_IN_FMAX):
+      return do_mpfr_arg2 (result, mpfr_max, arg0, arg1, format);
+
+    CASE_FLT_FN (BUILT_IN_POW):
+      return fold_const_pow (result, arg0, arg1, format);
+
+    default:
+      return false;
+    }
+}
+
+/* Try to evaluate:
+
+      *RESULT = FN (*ARG0, ARG1)
+
+   where FORMAT is the format of *RESULT and *ARG0.  Return true on
+   success.  */
+
+static bool
+fold_const_call_sss (real_value *result, built_in_function fn,
+		     const real_value *arg0, const wide_int_ref &arg1,
+		     const real_format *format)
+{
+  switch (fn)
+    {
+    CASE_FLT_FN (BUILT_IN_LDEXP):
+      return fold_const_builtin_load_exponent (result, arg0, arg1, format);
+
+    CASE_FLT_FN (BUILT_IN_SCALBN):
+    CASE_FLT_FN (BUILT_IN_SCALBLN):
+      return (format->b == 2
+	      && fold_const_builtin_load_exponent (result, arg0, arg1,
+						   format));
+
+    CASE_FLT_FN (BUILT_IN_POWI):
+      real_powi (result, format, arg0, arg1.to_shwi ());
+      return true;
+
+    default:
+      return false;
+    }
+}
+
+/* Try to evaluate:
+
+      *RESULT = FN (ARG0, *ARG1)
+
+   where FORMAT is the format of *RESULT and *ARG1.  Return true on
+   success.  */
+
+static bool
+fold_const_call_sss (real_value *result, built_in_function fn,
+		     const wide_int_ref &arg0, const real_value *arg1,
+		     const real_format *format)
+{
+  switch (fn)
+    {
+    CASE_FLT_FN (BUILT_IN_JN):
+      return do_mpfr_arg2 (result, mpfr_jn, arg0, arg1, format);
+
+    CASE_FLT_FN (BUILT_IN_YN):
+      return (real_compare (GT_EXPR, arg1, &dconst0)
+	      && do_mpfr_arg2 (result, mpfr_yn, arg0, arg1, format));
+
+    default:
+      return false;
+    }
+}
+
+/* Try to evaluate:
+
+      RESULT = fn (ARG0, ARG1)
+
+   where FORMAT is the format of the real and imaginary parts of RESULT
+   (RESULT_REAL and RESULT_IMAG), of ARG0 (ARG0_REAL and ARG0_IMAG)
+   and of ARG1 (ARG1_REAL and ARG1_IMAG).  Return true on success.  */
+
+static bool
+fold_const_call_ccc (real_value *result_real, real_value *result_imag,
+		     built_in_function fn, const real_value *arg0_real,
+		     const real_value *arg0_imag, const real_value *arg1_real,
+		     const real_value *arg1_imag, const real_format *format)
+{
+  switch (fn)
+    {
+    CASE_FLT_FN (BUILT_IN_CPOW):
+      return do_mpc_arg2 (result_real, result_imag, mpc_pow,
+			  arg0_real, arg0_imag, arg1_real, arg1_imag, format);
+
+    default:
+      return false;
+    }
+}
+
+/* Try to fold FN (ARG0, ARG1) to a constant.  Return the constant on success,
+   otherwise return null.  TYPE is the type of the return value.  */
+
+tree
+fold_const_call (built_in_function fn, tree type, tree arg0, tree arg1)
+{
+  machine_mode mode = TYPE_MODE (type);
+  machine_mode arg0_mode = TYPE_MODE (TREE_TYPE (arg0));
+  machine_mode arg1_mode = TYPE_MODE (TREE_TYPE (arg1));
+
+  if (arg0_mode == arg1_mode
+      && real_cst_p (arg0)
+      && real_cst_p (arg1))
+    {
+      gcc_checking_assert (SCALAR_FLOAT_MODE_P (arg0_mode));
+      if (mode == arg0_mode)
+	{
+	  /* real, real -> real.  */
+	  REAL_VALUE_TYPE result;
+	  if (fold_const_call_sss (&result, fn, TREE_REAL_CST_PTR (arg0),
+				   TREE_REAL_CST_PTR (arg1),
+				   REAL_MODE_FORMAT (mode)))
+	    return build_real (type, result);
+	}
+      return NULL_TREE;
+    }
+
+  if (real_cst_p (arg0)
+      && integer_cst_p (arg1))
+    {
+      gcc_checking_assert (SCALAR_FLOAT_MODE_P (arg0_mode));
+      if (mode == arg0_mode)
+	{
+	  /* real, int -> real.  */
+	  REAL_VALUE_TYPE result;
+	  if (fold_const_call_sss (&result, fn, TREE_REAL_CST_PTR (arg0),
+				   arg1, REAL_MODE_FORMAT (mode)))
+	    return build_real (type, result);
+	}
+      return NULL_TREE;
+    }
+
+  if (integer_cst_p (arg0)
+      && real_cst_p (arg1))
+    {
+      gcc_checking_assert (SCALAR_FLOAT_MODE_P (arg1_mode));
+      if (mode == arg1_mode)
+	{
+	  /* int, real -> real.  */
+	  REAL_VALUE_TYPE result;
+	  if (fold_const_call_sss (&result, fn, arg0,
+				   TREE_REAL_CST_PTR (arg1),
+				   REAL_MODE_FORMAT (mode)))
+	    return build_real (type, result);
+	}
+      return NULL_TREE;
+    }
+
+  if (arg0_mode == arg1_mode
+      && complex_cst_p (arg0)
+      && complex_cst_p (arg1))
+    {
+      gcc_checking_assert (COMPLEX_MODE_P (arg0_mode));
+      machine_mode inner_mode = GET_MODE_INNER (arg0_mode);
+      tree arg0r = TREE_REALPART (arg0);
+      tree arg0i = TREE_IMAGPART (arg0);
+      tree arg1r = TREE_REALPART (arg1);
+      tree arg1i = TREE_IMAGPART (arg1);
+      if (mode == arg0_mode
+	  && real_cst_p (arg0r)
+	  && real_cst_p (arg0i)
+	  && real_cst_p (arg1r)
+	  && real_cst_p (arg1i))
+	{
+	  /* complex real, complex real -> complex real.  */
+	  REAL_VALUE_TYPE result_real, result_imag;
+	  if (fold_const_call_ccc (&result_real, &result_imag, fn,
+				   TREE_REAL_CST_PTR (arg0r),
+				   TREE_REAL_CST_PTR (arg0i),
+				   TREE_REAL_CST_PTR (arg1r),
+				   TREE_REAL_CST_PTR (arg1i),
+				   REAL_MODE_FORMAT (inner_mode)))
+	    return build_complex (type,
+				  build_real (TREE_TYPE (type), result_real),
+				  build_real (TREE_TYPE (type), result_imag));
+	}
+      return NULL_TREE;
+    }
+
+  return NULL_TREE;
+}
+
+/* Try to evaluate:
+
+      *RESULT = FN (*ARG0, *ARG1, *ARG2)
+
+   in format FORMAT.  Return true on success.  */
+
+static bool
+fold_const_call_ssss (real_value *result, built_in_function fn,
+		      const real_value *arg0, const real_value *arg1,
+		      const real_value *arg2, const real_format *format)
+{
+  switch (fn)
+    {
+    CASE_FLT_FN (BUILT_IN_FMA):
+      return do_mpfr_arg3 (result, mpfr_fma, arg0, arg1, arg2, format);
+
+    default:
+      return false;
+    }
+}
+
+/* Try to fold FN (ARG0, ARG1, ARG2) to a constant.  Return the constant on
+   success, otherwise return null.  TYPE is the type of the return value.  */
+
+tree
+fold_const_call (built_in_function fn, tree type, tree arg0, tree arg1,
+		 tree arg2)
+{
+  machine_mode mode = TYPE_MODE (type);
+  machine_mode arg0_mode = TYPE_MODE (TREE_TYPE (arg0));
+  machine_mode arg1_mode = TYPE_MODE (TREE_TYPE (arg1));
+  machine_mode arg2_mode = TYPE_MODE (TREE_TYPE (arg2));
+
+  if (arg0_mode == arg1_mode
+      && arg0_mode == arg2_mode
+      && real_cst_p (arg0)
+      && real_cst_p (arg1)
+      && real_cst_p (arg2))
+    {
+      gcc_checking_assert (SCALAR_FLOAT_MODE_P (arg0_mode));
+      if (mode == arg0_mode)
+	{
+	  /* real, real, real -> real.  */
+	  REAL_VALUE_TYPE result;
+	  if (fold_const_call_ssss (&result, fn, TREE_REAL_CST_PTR (arg0),
+				    TREE_REAL_CST_PTR (arg1),
+				    TREE_REAL_CST_PTR (arg2),
+				    REAL_MODE_FORMAT (mode)))
+	    return build_real (type, result);
+	}
+      return NULL_TREE;
+    }
+
+  return NULL_TREE;
+}
+
+/* Fold a fma operation with arguments ARG[012].  */
+
+tree
+fold_fma (location_t, tree type, tree arg0, tree arg1, tree arg2)
+{
+  REAL_VALUE_TYPE result;
+  if (real_cst_p (arg0)
+      && real_cst_p (arg1)
+      && real_cst_p (arg2)
+      && do_mpfr_arg3 (&result, mpfr_fma, TREE_REAL_CST_PTR (arg0),
+		       TREE_REAL_CST_PTR (arg1), TREE_REAL_CST_PTR (arg2),
+		       REAL_MODE_FORMAT (TYPE_MODE (type))))
+    return build_real (type, result);
+
+  return NULL_TREE;
+}