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/* Simplify intrinsic functions at compile-time.
   Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
   Free Software Foundation, Inc.
   Contributed by Andy Vaught & Katherine Holcomb
 
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 "flags.h"
#include "gfortran.h"
#include "arith.h"
#include "intrinsic.h"
#include "target-memory.h"
 
/* Savely advance an array constructor by 'n' elements.
   Mainly used by simplifiers of transformational intrinsics.  */
#define ADVANCE(ctor, n) do { int i; for (i = 0; i < n && ctor; ++i) ctor = ctor->next; } while (0)
 
gfc_expr gfc_bad_expr;
 
 
/* Note that 'simplification' is not just transforming expressions.
   For functions that are not simplified at compile time, range
   checking is done if possible.
 
   The return convention is that each simplification function returns:
 
     A new expression node corresponding to the simplified arguments.
     The original arguments are destroyed by the caller, and must not
     be a part of the new expression.
 
     NULL pointer indicating that no simplification was possible and
     the original expression should remain intact.  If the
     simplification function sets the type and/or the function name
     via the pointer gfc_simple_expression, then this type is
     retained.
 
     An expression pointer to gfc_bad_expr (a static placeholder)
     indicating that some error has prevented simplification.  For
     example, sqrt(-1.0).  The error is generated within the function
     and should be propagated upwards
 
   By the time a simplification function gets control, it has been
   decided that the function call is really supposed to be the
   intrinsic.  No type checking is strictly necessary, since only
   valid types will be passed on.  On the other hand, a simplification
   subroutine may have to look at the type of an argument as part of
   its processing.
 
   Array arguments are never passed to these subroutines.
 
   The functions in this file don't have much comment with them, but
   everything is reasonably straight-forward.  The Standard, chapter 13
   is the best comment you'll find for this file anyway.  */
 
/* Range checks an expression node.  If all goes well, returns the
   node, otherwise returns &gfc_bad_expr and frees the node.  */
 
static gfc_expr *
range_check (gfc_expr *result, const char *name)
{
  if (result == NULL)
    return &gfc_bad_expr;
 
  switch (gfc_range_check (result))
    {
      case ARITH_OK:
        return result;
 
      case ARITH_OVERFLOW:
        gfc_error ("Result of %s overflows its kind at %L", name,
                   &result->where);
        break;
 
      case ARITH_UNDERFLOW:
        gfc_error ("Result of %s underflows its kind at %L", name,
                   &result->where);
        break;
 
      case ARITH_NAN:
        gfc_error ("Result of %s is NaN at %L", name, &result->where);
        break;
 
      default:
        gfc_error ("Result of %s gives range error for its kind at %L", name,
                   &result->where);
        break;
    }
 
  gfc_free_expr (result);
  return &gfc_bad_expr;
}
 
 
/* A helper function that gets an optional and possibly missing
   kind parameter.  Returns the kind, -1 if something went wrong.  */
 
static int
get_kind (bt type, gfc_expr *k, const char *name, int default_kind)
{
  int kind;
 
  if (k == NULL)
    return default_kind;
 
  if (k->expr_type != EXPR_CONSTANT)
    {
      gfc_error ("KIND parameter of %s at %L must be an initialization "
                 "expression", name, &k->where);
      return -1;
    }
 
  if (gfc_extract_int (k, &kind) != NULL
      || gfc_validate_kind (type, kind, true) < 0)
    {
      gfc_error ("Invalid KIND parameter of %s at %L", name, &k->where);
      return -1;
    }
 
  return kind;
}
 
 
/* Helper function to get an integer constant with a kind number given
   by an integer constant expression.  */
static gfc_expr *
int_expr_with_kind (int i, gfc_expr *kind, const char *name)
{
  gfc_expr *res = gfc_int_expr (i);
  res->ts.kind = get_kind (BT_INTEGER, kind, name, gfc_default_integer_kind);
  if (res->ts.kind == -1)
    return NULL;
  else
    return res;
}
 
 
/* Converts an mpz_t signed variable into an unsigned one, assuming
   two's complement representations and a binary width of bitsize.
   The conversion is a no-op unless x is negative; otherwise, it can
   be accomplished by masking out the high bits.  */
 
static void
convert_mpz_to_unsigned (mpz_t x, int bitsize)
{
  mpz_t mask;
 
  if (mpz_sgn (x) < 0)
    {
      /* Confirm that no bits above the signed range are unset.  */
      gcc_assert (mpz_scan0 (x, bitsize-1) == ULONG_MAX);
 
      mpz_init_set_ui (mask, 1);
      mpz_mul_2exp (mask, mask, bitsize);
      mpz_sub_ui (mask, mask, 1);
 
      mpz_and (x, x, mask);
 
      mpz_clear (mask);
    }
  else
    {
      /* Confirm that no bits above the signed range are set.  */
      gcc_assert (mpz_scan1 (x, bitsize-1) == ULONG_MAX);
    }
}
 
 
/* Converts an mpz_t unsigned variable into a signed one, assuming
   two's complement representations and a binary width of bitsize.
   If the bitsize-1 bit is set, this is taken as a sign bit and
   the number is converted to the corresponding negative number.  */
 
static void
convert_mpz_to_signed (mpz_t x, int bitsize)
{
  mpz_t mask;
 
  /* Confirm that no bits above the unsigned range are set.  */
  gcc_assert (mpz_scan1 (x, bitsize) == ULONG_MAX);
 
  if (mpz_tstbit (x, bitsize - 1) == 1)
    {
      mpz_init_set_ui (mask, 1);
      mpz_mul_2exp (mask, mask, bitsize);
      mpz_sub_ui (mask, mask, 1);
 
      /* We negate the number by hand, zeroing the high bits, that is
         make it the corresponding positive number, and then have it
         negated by GMP, giving the correct representation of the
         negative number.  */
      mpz_com (x, x);
      mpz_add_ui (x, x, 1);
      mpz_and (x, x, mask);
 
      mpz_neg (x, x);
 
      mpz_clear (mask);
    }
}
 
/* Test that the expression is an constant array.  */
 
static bool
is_constant_array_expr (gfc_expr *e)
{
  gfc_constructor *c;
 
  if (e == NULL)
    return true;
 
  if (e->expr_type != EXPR_ARRAY || !gfc_is_constant_expr (e))
    return false;
 
  for (c = e->value.constructor; c; c = c->next)
    if (c->expr->expr_type != EXPR_CONSTANT)
      return false;
 
  return true;
}
 
 
/* Initialize a transformational result expression with a given value.  */
 
static void
init_result_expr (gfc_expr *e, int init, gfc_expr *array)
{
  if (e && e->expr_type == EXPR_ARRAY)
    {
      gfc_constructor *ctor = e->value.constructor;
      while (ctor)
        {
          init_result_expr (ctor->expr, init, array);
          ctor = ctor->next;
        }
    }
  else if (e && e->expr_type == EXPR_CONSTANT)
    {
      int i = gfc_validate_kind (e->ts.type, e->ts.kind, false);
      int length;
      gfc_char_t *string;
 
      switch (e->ts.type)
        {
          case BT_LOGICAL:
            e->value.logical = (init ? 1 : 0);
            break;
 
          case BT_INTEGER:
            if (init == INT_MIN)
              mpz_set (e->value.integer, gfc_integer_kinds[i].min_int);
            else if (init == INT_MAX)
              mpz_set (e->value.integer, gfc_integer_kinds[i].huge);
            else
              mpz_set_si (e->value.integer, init);
            break;
 
          case BT_REAL:
            if (init == INT_MIN)
              {
                mpfr_set (e->value.real, gfc_real_kinds[i].huge, GFC_RND_MODE);
                mpfr_neg (e->value.real, e->value.real, GFC_RND_MODE);
              }
            else if (init == INT_MAX)
              mpfr_set (e->value.real, gfc_real_kinds[i].huge, GFC_RND_MODE);
            else
              mpfr_set_si (e->value.real, init, GFC_RND_MODE);
            break;
 
          case BT_COMPLEX:
            mpc_set_si (e->value.complex, init, GFC_MPC_RND_MODE);
            break;
 
          case BT_CHARACTER:
            if (init == INT_MIN)
              {
                gfc_expr *len = gfc_simplify_len (array, NULL);
                gfc_extract_int (len, &length);
                string = gfc_get_wide_string (length + 1);
                gfc_wide_memset (string, 0, length);
              }
            else if (init == INT_MAX)
              {
                gfc_expr *len = gfc_simplify_len (array, NULL);
                gfc_extract_int (len, &length);
                string = gfc_get_wide_string (length + 1);
                gfc_wide_memset (string, 255, length);
              }
            else
              {
                length = 0;
                string = gfc_get_wide_string (1);
              }
 
            string[length] = '\0';
            e->value.character.length = length;
            e->value.character.string = string;
            break;
 
          default:
            gcc_unreachable();
        }
    }
  else
    gcc_unreachable();
}
 
 
/* Helper function for gfc_simplify_dot_product() and gfc_simplify_matmul.  */
 
static gfc_expr *
compute_dot_product (gfc_constructor *ctor_a, int stride_a,
                     gfc_constructor *ctor_b, int stride_b)
{
  gfc_expr *result;
  gfc_expr *a = ctor_a->expr, *b = ctor_b->expr;
 
  gcc_assert (gfc_compare_types (&a->ts, &b->ts));
 
  result = gfc_constant_result (a->ts.type, a->ts.kind, &a->where);
  init_result_expr (result, 0, NULL);
 
  while (ctor_a && ctor_b)
    {
      /* Copying of expressions is required as operands are free'd
         by the gfc_arith routines.  */
      switch (result->ts.type)
        {
          case BT_LOGICAL:
            result = gfc_or (result,
                             gfc_and (gfc_copy_expr (ctor_a->expr),
                                      gfc_copy_expr (ctor_b->expr)));
            break;
 
          case BT_INTEGER:
          case BT_REAL:
          case BT_COMPLEX:
            result = gfc_add (result,
                              gfc_multiply (gfc_copy_expr (ctor_a->expr),
                                            gfc_copy_expr (ctor_b->expr)));
            break;
 
          default:
            gcc_unreachable();
        }
 
      ADVANCE (ctor_a, stride_a);
      ADVANCE (ctor_b, stride_b);
    }
 
  return result;
}
 
 
/* Build a result expression for transformational intrinsics,
   depending on DIM. */
 
static gfc_expr *
transformational_result (gfc_expr *array, gfc_expr *dim, bt type,
                         int kind, locus* where)
{
  gfc_expr *result;
  int i, nelem;
 
  if (!dim || array->rank == 1)
    return gfc_constant_result (type, kind, where);
 
  result = gfc_start_constructor (type, kind, where);
  result->shape = gfc_copy_shape_excluding (array->shape, array->rank, dim);
  result->rank = array->rank - 1;
 
  /* gfc_array_size() would count the number of elements in the constructor,
     we have not built those yet.  */
  nelem = 1;
  for  (i = 0; i < result->rank; ++i)
    nelem *= mpz_get_ui (result->shape[i]);
 
  for (i = 0; i < nelem; ++i)
    {
      gfc_expr *e = gfc_constant_result (type, kind, where);
      gfc_append_constructor (result, e);
    }
 
  return result;
}
 
 
typedef gfc_expr* (*transformational_op)(gfc_expr*, gfc_expr*);
 
/* Wrapper function, implements 'op1 += 1'. Only called if MASK
   of COUNT intrinsic is .TRUE..
 
   Interface and implimentation mimics arith functions as
   gfc_add, gfc_multiply, etc.  */
 
static gfc_expr* gfc_count (gfc_expr *op1, gfc_expr *op2)
{
  gfc_expr *result;
 
  gcc_assert (op1->ts.type == BT_INTEGER);
  gcc_assert (op2->ts.type == BT_LOGICAL);
  gcc_assert (op2->value.logical);
 
  result = gfc_copy_expr (op1);
  mpz_add_ui (result->value.integer, result->value.integer, 1);
 
  gfc_free_expr (op1);
  gfc_free_expr (op2);
  return result;
}
 
 
/* Transforms an ARRAY with operation OP, according to MASK, to a
   scalar RESULT. E.g. called if
 
     REAL, PARAMETER :: array(n, m) = ...
     REAL, PARAMETER :: s = SUM(array)
 
  where OP == gfc_add().  */
 
static gfc_expr *
simplify_transformation_to_scalar (gfc_expr *result, gfc_expr *array, gfc_expr *mask,
                                   transformational_op op)
{
  gfc_expr *a, *m;
  gfc_constructor *array_ctor, *mask_ctor;
 
  /* Shortcut for constant .FALSE. MASK.  */
  if (mask
      && mask->expr_type == EXPR_CONSTANT
      && !mask->value.logical)
    return result;
 
  array_ctor = array->value.constructor;
  mask_ctor = NULL;
  if (mask && mask->expr_type == EXPR_ARRAY)
    mask_ctor = mask->value.constructor;
 
  while (array_ctor)
    {
      a = array_ctor->expr;
      array_ctor = array_ctor->next;
 
      /* A constant MASK equals .TRUE. here and can be ignored.  */
      if (mask_ctor)
        {
          m = mask_ctor->expr;
          mask_ctor = mask_ctor->next;
          if (!m->value.logical)
            continue;
        }
 
      result = op (result, gfc_copy_expr (a));
    }
 
  return result;
}
 
/* Transforms an ARRAY with operation OP, according to MASK, to an
   array RESULT. E.g. called if
 
     REAL, PARAMETER :: array(n, m) = ...
     REAL, PARAMETER :: s(n) = PROD(array, DIM=1)
 
  where OP == gfc_multiply().  */
 
static gfc_expr *
simplify_transformation_to_array (gfc_expr *result, gfc_expr *array, gfc_expr *dim,
                                  gfc_expr *mask, transformational_op op)
{
  mpz_t size;
  int done, i, n, arraysize, resultsize, dim_index, dim_extent, dim_stride;
  gfc_expr **arrayvec, **resultvec, **base, **src, **dest;
  gfc_constructor *array_ctor, *mask_ctor, *result_ctor;
 
  int count[GFC_MAX_DIMENSIONS], extent[GFC_MAX_DIMENSIONS],
      sstride[GFC_MAX_DIMENSIONS], dstride[GFC_MAX_DIMENSIONS],
      tmpstride[GFC_MAX_DIMENSIONS];
 
  /* Shortcut for constant .FALSE. MASK.  */
  if (mask
      && mask->expr_type == EXPR_CONSTANT
      && !mask->value.logical)
    return result;
 
  /* Build an indexed table for array element expressions to minimize
     linked-list traversal. Masked elements are set to NULL.  */
  gfc_array_size (array, &size);
  arraysize = mpz_get_ui (size);
 
  arrayvec = (gfc_expr**) gfc_getmem (sizeof (gfc_expr*) * arraysize);
 
  array_ctor = array->value.constructor;
  mask_ctor = NULL;
  if (mask && mask->expr_type == EXPR_ARRAY)
    mask_ctor = mask->value.constructor;
 
  for (i = 0; i < arraysize; ++i)
    {
      arrayvec[i] = array_ctor->expr;
      array_ctor = array_ctor->next;
 
      if (mask_ctor)
        {
          if (!mask_ctor->expr->value.logical)
            arrayvec[i] = NULL;
 
          mask_ctor = mask_ctor->next;
        }
    }
 
  /* Same for the result expression.  */
  gfc_array_size (result, &size);
  resultsize = mpz_get_ui (size);
  mpz_clear (size);
 
  resultvec = (gfc_expr**) gfc_getmem (sizeof (gfc_expr*) * resultsize);
  result_ctor = result->value.constructor;
  for (i = 0; i < resultsize; ++i)
    {
      resultvec[i] = result_ctor->expr;
      result_ctor = result_ctor->next;
    }
 
  gfc_extract_int (dim, &dim_index);
  dim_index -= 1;               /* zero-base index */
  dim_extent = 0;
  dim_stride = 0;
 
  for (i = 0, n = 0; i < array->rank; ++i)
    {
      count[i] = 0;
      tmpstride[i] = (i == 0) ? 1 : tmpstride[i-1] * mpz_get_si (array->shape[i-1]);
      if (i == dim_index)
        {
          dim_extent = mpz_get_si (array->shape[i]);
          dim_stride = tmpstride[i];
          continue;
        }
 
      extent[n] = mpz_get_si (array->shape[i]);
      sstride[n] = tmpstride[i];
      dstride[n] = (n == 0) ? 1 : dstride[n-1] * extent[n-1];
      n += 1;
    }
 
  done = false;
  base = arrayvec;
  dest = resultvec;
  while (!done)
    {
      for (src = base, n = 0; n < dim_extent; src += dim_stride, ++n)
        if (*src)
          *dest = op (*dest, gfc_copy_expr (*src));
 
      count[0]++;
      base += sstride[0];
      dest += dstride[0];
 
      n = 0;
      while (!done && count[n] == extent[n])
        {
          count[n] = 0;
          base -= sstride[n] * extent[n];
          dest -= dstride[n] * extent[n];
 
          n++;
          if (n < result->rank)
            {
              count [n]++;
              base += sstride[n];
              dest += dstride[n];
            }
          else
            done = true;
       }
    }
 
  /* Place updated expression in result constructor.  */
  result_ctor = result->value.constructor;
  for (i = 0; i < resultsize; ++i)
    {
      result_ctor->expr = resultvec[i];
      result_ctor = result_ctor->next;
    }
 
  gfc_free (arrayvec);
  gfc_free (resultvec);
  return result;
}
 
 
 
/********************** Simplification functions *****************************/
 
gfc_expr *
gfc_simplify_abs (gfc_expr *e)
{
  gfc_expr *result;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  switch (e->ts.type)
    {
    case BT_INTEGER:
      result = gfc_constant_result (BT_INTEGER, e->ts.kind, &e->where);
 
      mpz_abs (result->value.integer, e->value.integer);
 
      result = range_check (result, "IABS");
      break;
 
    case BT_REAL:
      result = gfc_constant_result (BT_REAL, e->ts.kind, &e->where);
 
      mpfr_abs (result->value.real, e->value.real, GFC_RND_MODE);
 
      result = range_check (result, "ABS");
      break;
 
    case BT_COMPLEX:
      result = gfc_constant_result (BT_REAL, e->ts.kind, &e->where);
 
      gfc_set_model_kind (e->ts.kind);
 
      mpc_abs (result->value.real, e->value.complex, GFC_RND_MODE);
      result = range_check (result, "CABS");
      break;
 
    default:
      gfc_internal_error ("gfc_simplify_abs(): Bad type");
    }
 
  return result;
}
 
 
static gfc_expr *
simplify_achar_char (gfc_expr *e, gfc_expr *k, const char *name, bool ascii)
{
  gfc_expr *result;
  int kind;
  bool too_large = false;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  kind = get_kind (BT_CHARACTER, k, name, gfc_default_character_kind);
  if (kind == -1)
    return &gfc_bad_expr;
 
  if (mpz_cmp_si (e->value.integer, 0) < 0)
    {
      gfc_error ("Argument of %s function at %L is negative", name,
                 &e->where);
      return &gfc_bad_expr;
    }
 
  if (ascii && gfc_option.warn_surprising
      && mpz_cmp_si (e->value.integer, 127) > 0)
    gfc_warning ("Argument of %s function at %L outside of range [0,127]",
                 name, &e->where);
 
  if (kind == 1 && mpz_cmp_si (e->value.integer, 255) > 0)
    too_large = true;
  else if (kind == 4)
    {
      mpz_t t;
      mpz_init_set_ui (t, 2);
      mpz_pow_ui (t, t, 32);
      mpz_sub_ui (t, t, 1);
      if (mpz_cmp (e->value.integer, t) > 0)
        too_large = true;
      mpz_clear (t);
    }
 
  if (too_large)
    {
      gfc_error ("Argument of %s function at %L is too large for the "
                 "collating sequence of kind %d", name, &e->where, kind);
      return &gfc_bad_expr;
    }
 
  result = gfc_constant_result (BT_CHARACTER, kind, &e->where);
  result->value.character.string = gfc_get_wide_string (2);
  result->value.character.length = 1;
  result->value.character.string[0] = mpz_get_ui (e->value.integer);
  result->value.character.string[1] = '\0';     /* For debugger */
  return result;
}
 
 
 
/* We use the processor's collating sequence, because all
   systems that gfortran currently works on are ASCII.  */
 
gfc_expr *
gfc_simplify_achar (gfc_expr *e, gfc_expr *k)
{
  return simplify_achar_char (e, k, "ACHAR", true);
}
 
 
gfc_expr *
gfc_simplify_acos (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  switch (x->ts.type)
    {
      case BT_REAL:
        if (mpfr_cmp_si (x->value.real, 1) > 0
            || mpfr_cmp_si (x->value.real, -1) < 0)
          {
            gfc_error ("Argument of ACOS at %L must be between -1 and 1",
                       &x->where);
            return &gfc_bad_expr;
          }
        result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
        mpfr_acos (result->value.real, x->value.real, GFC_RND_MODE);
        break;
      case BT_COMPLEX:
        result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
        mpc_acos (result->value.complex, x->value.complex, GFC_MPC_RND_MODE);
        break;
      default:
        gfc_internal_error ("in gfc_simplify_acos(): Bad type");
    }
 
 
  return range_check (result, "ACOS");
}
 
gfc_expr *
gfc_simplify_acosh (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  switch (x->ts.type)
    {
      case BT_REAL:
        if (mpfr_cmp_si (x->value.real, 1) < 0)
          {
            gfc_error ("Argument of ACOSH at %L must not be less than 1",
                       &x->where);
            return &gfc_bad_expr;
          }
 
        result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
        mpfr_acosh (result->value.real, x->value.real, GFC_RND_MODE);
        break;
      case BT_COMPLEX:
        result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
        mpc_acosh (result->value.complex, x->value.complex, GFC_MPC_RND_MODE);
        break;
      default:
        gfc_internal_error ("in gfc_simplify_acosh(): Bad type");
    }
 
  return range_check (result, "ACOSH");
}
 
gfc_expr *
gfc_simplify_adjustl (gfc_expr *e)
{
  gfc_expr *result;
  int count, i, len;
  gfc_char_t ch;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  len = e->value.character.length;
 
  result = gfc_constant_result (BT_CHARACTER, e->ts.kind, &e->where);
 
  result->value.character.length = len;
  result->value.character.string = gfc_get_wide_string (len + 1);
 
  for (count = 0, i = 0; i < len; ++i)
    {
      ch = e->value.character.string[i];
      if (ch != ' ')
        break;
      ++count;
    }
 
  for (i = 0; i < len - count; ++i)
    result->value.character.string[i] = e->value.character.string[count + i];
 
  for (i = len - count; i < len; ++i)
    result->value.character.string[i] = ' ';
 
  result->value.character.string[len] = '\0';   /* For debugger */
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_adjustr (gfc_expr *e)
{
  gfc_expr *result;
  int count, i, len;
  gfc_char_t ch;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  len = e->value.character.length;
 
  result = gfc_constant_result (BT_CHARACTER, e->ts.kind, &e->where);
 
  result->value.character.length = len;
  result->value.character.string = gfc_get_wide_string (len + 1);
 
  for (count = 0, i = len - 1; i >= 0; --i)
    {
      ch = e->value.character.string[i];
      if (ch != ' ')
        break;
      ++count;
    }
 
  for (i = 0; i < count; ++i)
    result->value.character.string[i] = ' ';
 
  for (i = count; i < len; ++i)
    result->value.character.string[i] = e->value.character.string[i - count];
 
  result->value.character.string[len] = '\0';   /* For debugger */
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_aimag (gfc_expr *e)
{
  gfc_expr *result;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (BT_REAL, e->ts.kind, &e->where);
  mpfr_set (result->value.real, mpc_imagref (e->value.complex), GFC_RND_MODE);
 
  return range_check (result, "AIMAG");
}
 
 
gfc_expr *
gfc_simplify_aint (gfc_expr *e, gfc_expr *k)
{
  gfc_expr *rtrunc, *result;
  int kind;
 
  kind = get_kind (BT_REAL, k, "AINT", e->ts.kind);
  if (kind == -1)
    return &gfc_bad_expr;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  rtrunc = gfc_copy_expr (e);
 
  mpfr_trunc (rtrunc->value.real, e->value.real);
 
  result = gfc_real2real (rtrunc, kind);
  gfc_free_expr (rtrunc);
 
  return range_check (result, "AINT");
}
 
 
gfc_expr *
gfc_simplify_all (gfc_expr *mask, gfc_expr *dim)
{
  gfc_expr *result;
 
  if (!is_constant_array_expr (mask)
      || !gfc_is_constant_expr (dim))
    return NULL;
 
  result = transformational_result (mask, dim, mask->ts.type,
                                    mask->ts.kind, &mask->where);
  init_result_expr (result, true, NULL);
 
  return !dim || mask->rank == 1 ?
    simplify_transformation_to_scalar (result, mask, NULL, gfc_and) :
    simplify_transformation_to_array (result, mask, dim, NULL, gfc_and);
}
 
 
gfc_expr *
gfc_simplify_dint (gfc_expr *e)
{
  gfc_expr *rtrunc, *result;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  rtrunc = gfc_copy_expr (e);
 
  mpfr_trunc (rtrunc->value.real, e->value.real);
 
  result = gfc_real2real (rtrunc, gfc_default_double_kind);
  gfc_free_expr (rtrunc);
 
  return range_check (result, "DINT");
}
 
 
gfc_expr *
gfc_simplify_anint (gfc_expr *e, gfc_expr *k)
{
  gfc_expr *result;
  int kind;
 
  kind = get_kind (BT_REAL, k, "ANINT", e->ts.kind);
  if (kind == -1)
    return &gfc_bad_expr;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (e->ts.type, kind, &e->where);
 
  mpfr_round (result->value.real, e->value.real);
 
  return range_check (result, "ANINT");
}
 
 
gfc_expr *
gfc_simplify_and (gfc_expr *x, gfc_expr *y)
{
  gfc_expr *result;
  int kind;
 
  if (x->expr_type != EXPR_CONSTANT || y->expr_type != EXPR_CONSTANT)
    return NULL;
 
  kind = x->ts.kind > y->ts.kind ? x->ts.kind : y->ts.kind;
  if (x->ts.type == BT_INTEGER)
    {
      result = gfc_constant_result (BT_INTEGER, kind, &x->where);
      mpz_and (result->value.integer, x->value.integer, y->value.integer);
      return range_check (result, "AND");
    }
  else /* BT_LOGICAL */
    {
      result = gfc_constant_result (BT_LOGICAL, kind, &x->where);
      result->value.logical = x->value.logical && y->value.logical;
      return result;
    }
}
 
 
gfc_expr *
gfc_simplify_any (gfc_expr *mask, gfc_expr *dim)
{
  gfc_expr *result;
 
  if (!is_constant_array_expr (mask)
      || !gfc_is_constant_expr (dim))
    return NULL;
 
  result = transformational_result (mask, dim, mask->ts.type,
                                    mask->ts.kind, &mask->where);
  init_result_expr (result, false, NULL);
 
  return !dim || mask->rank == 1 ?
    simplify_transformation_to_scalar (result, mask, NULL, gfc_or) :
    simplify_transformation_to_array (result, mask, dim, NULL, gfc_or);
}
 
 
gfc_expr *
gfc_simplify_dnint (gfc_expr *e)
{
  gfc_expr *result;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (BT_REAL, gfc_default_double_kind, &e->where);
 
  mpfr_round (result->value.real, e->value.real);
 
  return range_check (result, "DNINT");
}
 
 
gfc_expr *
gfc_simplify_asin (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  switch (x->ts.type)
    {
      case BT_REAL:
        if (mpfr_cmp_si (x->value.real, 1) > 0
            || mpfr_cmp_si (x->value.real, -1) < 0)
          {
            gfc_error ("Argument of ASIN at %L must be between -1 and 1",
                       &x->where);
            return &gfc_bad_expr;
          }
        result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
        mpfr_asin (result->value.real, x->value.real, GFC_RND_MODE);
        break;
      case BT_COMPLEX:
        result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
        mpc_asin (result->value.complex, x->value.complex, GFC_MPC_RND_MODE);
        break;
      default:
        gfc_internal_error ("in gfc_simplify_asin(): Bad type");
    }
 
  return range_check (result, "ASIN");
}
 
 
gfc_expr *
gfc_simplify_asinh (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  switch (x->ts.type)
    {
      case BT_REAL:
        result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
        mpfr_asinh (result->value.real, x->value.real, GFC_RND_MODE);
        break;
      case BT_COMPLEX:
        result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
        mpc_asinh (result->value.complex, x->value.complex, GFC_MPC_RND_MODE);
        break;
      default:
        gfc_internal_error ("in gfc_simplify_asinh(): Bad type");
    }
 
  return range_check (result, "ASINH");
}
 
 
gfc_expr *
gfc_simplify_atan (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  switch (x->ts.type)
    {
      case BT_REAL:
        result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
        mpfr_atan (result->value.real, x->value.real, GFC_RND_MODE);
        break;
      case BT_COMPLEX:
        result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
        mpc_atan (result->value.complex, x->value.complex, GFC_MPC_RND_MODE);
        break;
      default:
        gfc_internal_error ("in gfc_simplify_atan(): Bad type");
    }
 
  return range_check (result, "ATAN");
}
 
 
gfc_expr *
gfc_simplify_atanh (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  switch (x->ts.type)
    {
      case BT_REAL:
        if (mpfr_cmp_si (x->value.real, 1) >= 0
            || mpfr_cmp_si (x->value.real, -1) <= 0)
          {
            gfc_error ("Argument of ATANH at %L must be inside the range -1 "
                       "to 1", &x->where);
            return &gfc_bad_expr;
          }
 
        result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
        mpfr_atanh (result->value.real, x->value.real, GFC_RND_MODE);
        break;
      case BT_COMPLEX:
        result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
        mpc_atanh (result->value.complex, x->value.complex, GFC_MPC_RND_MODE);
        break;
      default:
        gfc_internal_error ("in gfc_simplify_atanh(): Bad type");
    }
 
  return range_check (result, "ATANH");
}
 
 
gfc_expr *
gfc_simplify_atan2 (gfc_expr *y, gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT || y->expr_type != EXPR_CONSTANT)
    return NULL;
 
  if (mpfr_sgn (y->value.real) == 0 && mpfr_sgn (x->value.real) == 0)
    {
      gfc_error ("If first argument of ATAN2 %L is zero, then the "
                 "second argument must not be zero", &x->where);
      return &gfc_bad_expr;
    }
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
 
  mpfr_atan2 (result->value.real, y->value.real, x->value.real, GFC_RND_MODE);
 
  return range_check (result, "ATAN2");
}
 
 
gfc_expr *
gfc_simplify_bessel_j0 (gfc_expr *x ATTRIBUTE_UNUSED)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
  mpfr_j0 (result->value.real, x->value.real, GFC_RND_MODE);
 
  return range_check (result, "BESSEL_J0");
}
 
 
gfc_expr *
gfc_simplify_bessel_j1 (gfc_expr *x ATTRIBUTE_UNUSED)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
  mpfr_j1 (result->value.real, x->value.real, GFC_RND_MODE);
 
  return range_check (result, "BESSEL_J1");
}
 
 
gfc_expr *
gfc_simplify_bessel_jn (gfc_expr *order ATTRIBUTE_UNUSED,
                        gfc_expr *x ATTRIBUTE_UNUSED)
{
  gfc_expr *result;
  long n;
 
  if (x->expr_type != EXPR_CONSTANT || order->expr_type != EXPR_CONSTANT)
    return NULL;
 
  n = mpz_get_si (order->value.integer);
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
  mpfr_jn (result->value.real, n, x->value.real, GFC_RND_MODE);
 
  return range_check (result, "BESSEL_JN");
}
 
 
gfc_expr *
gfc_simplify_bessel_y0 (gfc_expr *x ATTRIBUTE_UNUSED)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
  mpfr_y0 (result->value.real, x->value.real, GFC_RND_MODE);
 
  return range_check (result, "BESSEL_Y0");
}
 
 
gfc_expr *
gfc_simplify_bessel_y1 (gfc_expr *x ATTRIBUTE_UNUSED)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
  mpfr_y1 (result->value.real, x->value.real, GFC_RND_MODE);
 
  return range_check (result, "BESSEL_Y1");
}
 
 
gfc_expr *
gfc_simplify_bessel_yn (gfc_expr *order ATTRIBUTE_UNUSED,
                        gfc_expr *x ATTRIBUTE_UNUSED)
{
  gfc_expr *result;
  long n;
 
  if (x->expr_type != EXPR_CONSTANT || order->expr_type != EXPR_CONSTANT)
    return NULL;
 
  n = mpz_get_si (order->value.integer);
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
  mpfr_yn (result->value.real, n, x->value.real, GFC_RND_MODE);
 
  return range_check (result, "BESSEL_YN");
}
 
 
gfc_expr *
gfc_simplify_bit_size (gfc_expr *e)
{
  gfc_expr *result;
  int i;
 
  i = gfc_validate_kind (e->ts.type, e->ts.kind, false);
  result = gfc_constant_result (BT_INTEGER, e->ts.kind, &e->where);
  mpz_set_ui (result->value.integer, gfc_integer_kinds[i].bit_size);
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_btest (gfc_expr *e, gfc_expr *bit)
{
  int b;
 
  if (e->expr_type != EXPR_CONSTANT || bit->expr_type != EXPR_CONSTANT)
    return NULL;
 
  if (gfc_extract_int (bit, &b) != NULL || b < 0)
    return gfc_logical_expr (0, &e->where);
 
  return gfc_logical_expr (mpz_tstbit (e->value.integer, b), &e->where);
}
 
 
gfc_expr *
gfc_simplify_ceiling (gfc_expr *e, gfc_expr *k)
{
  gfc_expr *ceil, *result;
  int kind;
 
  kind = get_kind (BT_INTEGER, k, "CEILING", gfc_default_integer_kind);
  if (kind == -1)
    return &gfc_bad_expr;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (BT_INTEGER, kind, &e->where);
 
  ceil = gfc_copy_expr (e);
 
  mpfr_ceil (ceil->value.real, e->value.real);
  gfc_mpfr_to_mpz (result->value.integer, ceil->value.real, &e->where);
 
  gfc_free_expr (ceil);
 
  return range_check (result, "CEILING");
}
 
 
gfc_expr *
gfc_simplify_char (gfc_expr *e, gfc_expr *k)
{
  return simplify_achar_char (e, k, "CHAR", false);
}
 
 
/* Common subroutine for simplifying CMPLX and DCMPLX.  */
 
static gfc_expr *
simplify_cmplx (const char *name, gfc_expr *x, gfc_expr *y, int kind)
{
  gfc_expr *result;
 
  result = gfc_constant_result (BT_COMPLEX, kind, &x->where);
 
  switch (x->ts.type)
    {
    case BT_INTEGER:
      if (!x->is_boz)
        mpc_set_z (result->value.complex, x->value.integer, GFC_MPC_RND_MODE);
      break;
 
    case BT_REAL:
      mpc_set_fr (result->value.complex, x->value.real, GFC_RND_MODE);
      break;
 
    case BT_COMPLEX:
      mpc_set (result->value.complex, x->value.complex, GFC_MPC_RND_MODE);
      break;
 
    default:
      gfc_internal_error ("gfc_simplify_dcmplx(): Bad type (x)");
    }
 
  if (y != NULL)
    {
      switch (y->ts.type)
        {
        case BT_INTEGER:
          if (!y->is_boz)
            mpfr_set_z (mpc_imagref (result->value.complex),
                        y->value.integer, GFC_RND_MODE);
          break;
 
        case BT_REAL:
          mpfr_set (mpc_imagref (result->value.complex),
                    y->value.real, GFC_RND_MODE);
          break;
 
        default:
          gfc_internal_error ("gfc_simplify_dcmplx(): Bad type (y)");
        }
    }
 
  /* Handle BOZ.  */
  if (x->is_boz)
    {
      gfc_typespec ts;
      gfc_clear_ts (&ts);
      ts.kind = result->ts.kind;
      ts.type = BT_REAL;
      if (!gfc_convert_boz (x, &ts))
        return &gfc_bad_expr;
      mpfr_set (mpc_realref (result->value.complex),
                x->value.real, GFC_RND_MODE);
    }
 
  if (y && y->is_boz)
    {
      gfc_typespec ts;
      gfc_clear_ts (&ts);
      ts.kind = result->ts.kind;
      ts.type = BT_REAL;
      if (!gfc_convert_boz (y, &ts))
        return &gfc_bad_expr;
      mpfr_set (mpc_imagref (result->value.complex),
                y->value.real, GFC_RND_MODE);
    }
 
  return range_check (result, name);
}
 
 
/* Function called when we won't simplify an expression like CMPLX (or
   COMPLEX or DCMPLX) but still want to convert BOZ arguments.  */
 
static gfc_expr *
only_convert_cmplx_boz (gfc_expr *x, gfc_expr *y, int kind)
{
  gfc_typespec ts;
  gfc_clear_ts (&ts);
  ts.type = BT_REAL;
  ts.kind = kind;
 
  if (x->is_boz && !gfc_convert_boz (x, &ts))
    return &gfc_bad_expr;
 
  if (y && y->is_boz && !gfc_convert_boz (y, &ts))
    return &gfc_bad_expr;
 
  return NULL;
}
 
 
gfc_expr *
gfc_simplify_cmplx (gfc_expr *x, gfc_expr *y, gfc_expr *k)
{
  int kind;
 
  kind = get_kind (BT_REAL, k, "CMPLX", gfc_default_real_kind);
  if (kind == -1)
    return &gfc_bad_expr;
 
  if (x->expr_type != EXPR_CONSTANT
      || (y != NULL && y->expr_type != EXPR_CONSTANT))
    return only_convert_cmplx_boz (x, y, kind);
 
  return simplify_cmplx ("CMPLX", x, y, kind);
}
 
 
gfc_expr *
gfc_simplify_complex (gfc_expr *x, gfc_expr *y)
{
  int kind;
 
  if (x->ts.type == BT_INTEGER)
    {
      if (y->ts.type == BT_INTEGER)
        kind = gfc_default_real_kind;
      else
        kind = y->ts.kind;
    }
  else
    {
      if (y->ts.type == BT_REAL)
        kind = (x->ts.kind > y->ts.kind) ? x->ts.kind : y->ts.kind;
      else
        kind = x->ts.kind;
    }
 
  if (x->expr_type != EXPR_CONSTANT
      || (y != NULL && y->expr_type != EXPR_CONSTANT))
    return only_convert_cmplx_boz (x, y, kind);
 
  return simplify_cmplx ("COMPLEX", x, y, kind);
}
 
 
gfc_expr *
gfc_simplify_conjg (gfc_expr *e)
{
  gfc_expr *result;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_copy_expr (e);
  mpc_conj (result->value.complex, result->value.complex, GFC_MPC_RND_MODE);
  return range_check (result, "CONJG");
}
 
 
gfc_expr *
gfc_simplify_cos (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
 
  switch (x->ts.type)
    {
    case BT_REAL:
      mpfr_cos (result->value.real, x->value.real, GFC_RND_MODE);
      break;
    case BT_COMPLEX:
      gfc_set_model_kind (x->ts.kind);
      mpc_cos (result->value.complex, x->value.complex, GFC_MPC_RND_MODE);
      break;
    default:
      gfc_internal_error ("in gfc_simplify_cos(): Bad type");
    }
 
  return range_check (result, "COS");
 
}
 
 
gfc_expr *
gfc_simplify_cosh (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
 
  if (x->ts.type == BT_REAL)
    mpfr_cosh (result->value.real, x->value.real, GFC_RND_MODE);
  else if (x->ts.type == BT_COMPLEX)
    mpc_cosh (result->value.complex, x->value.complex, GFC_MPC_RND_MODE);
  else
    gcc_unreachable ();
 
  return range_check (result, "COSH");
}
 
 
gfc_expr *
gfc_simplify_count (gfc_expr *mask, gfc_expr *dim, gfc_expr *kind)
{
  gfc_expr *result;
 
  if (!is_constant_array_expr (mask)
      || !gfc_is_constant_expr (dim)
      || !gfc_is_constant_expr (kind))
    return NULL;
 
  result = transformational_result (mask, dim,
                                    BT_INTEGER,
                                    get_kind (BT_INTEGER, kind, "COUNT",
                                              gfc_default_integer_kind),
                                    &mask->where);
 
  init_result_expr (result, 0, NULL);
 
  /* Passing MASK twice, once as data array, once as mask.
     Whenever gfc_count is called, '1' is added to the result.  */
  return !dim || mask->rank == 1 ?
    simplify_transformation_to_scalar (result, mask, mask, gfc_count) :
    simplify_transformation_to_array (result, mask, dim, mask, gfc_count);
}
 
 
gfc_expr *
gfc_simplify_dcmplx (gfc_expr *x, gfc_expr *y)
{
 
  if (x->expr_type != EXPR_CONSTANT
      || (y != NULL && y->expr_type != EXPR_CONSTANT))
    return only_convert_cmplx_boz (x, y, gfc_default_double_kind);
 
  return simplify_cmplx ("DCMPLX", x, y, gfc_default_double_kind);
}
 
 
gfc_expr *
gfc_simplify_dble (gfc_expr *e)
{
  gfc_expr *result = NULL;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  switch (e->ts.type)
    {
    case BT_INTEGER:
      if (!e->is_boz)
        result = gfc_int2real (e, gfc_default_double_kind);
      break;
 
    case BT_REAL:
      result = gfc_real2real (e, gfc_default_double_kind);
      break;
 
    case BT_COMPLEX:
      result = gfc_complex2real (e, gfc_default_double_kind);
      break;
 
    default:
      gfc_internal_error ("gfc_simplify_dble(): bad type at %L", &e->where);
    }
 
  if (e->ts.type == BT_INTEGER && e->is_boz)
    {
      gfc_typespec ts;
      gfc_clear_ts (&ts);
      ts.type = BT_REAL;
      ts.kind = gfc_default_double_kind;
      result = gfc_copy_expr (e);
      if (!gfc_convert_boz (result, &ts))
        {
          gfc_free_expr (result);
          return &gfc_bad_expr;
        }
    }
 
  return range_check (result, "DBLE");
}
 
 
gfc_expr *
gfc_simplify_digits (gfc_expr *x)
{
  int i, digits;
 
  i = gfc_validate_kind (x->ts.type, x->ts.kind, false);
  switch (x->ts.type)
    {
    case BT_INTEGER:
      digits = gfc_integer_kinds[i].digits;
      break;
 
    case BT_REAL:
    case BT_COMPLEX:
      digits = gfc_real_kinds[i].digits;
      break;
 
    default:
      gcc_unreachable ();
    }
 
  return gfc_int_expr (digits);
}
 
 
gfc_expr *
gfc_simplify_dim (gfc_expr *x, gfc_expr *y)
{
  gfc_expr *result;
  int kind;
 
  if (x->expr_type != EXPR_CONSTANT || y->expr_type != EXPR_CONSTANT)
    return NULL;
 
  kind = x->ts.kind > y->ts.kind ? x->ts.kind : y->ts.kind;
  result = gfc_constant_result (x->ts.type, kind, &x->where);
 
  switch (x->ts.type)
    {
    case BT_INTEGER:
      if (mpz_cmp (x->value.integer, y->value.integer) > 0)
        mpz_sub (result->value.integer, x->value.integer, y->value.integer);
      else
        mpz_set_ui (result->value.integer, 0);
 
      break;
 
    case BT_REAL:
      if (mpfr_cmp (x->value.real, y->value.real) > 0)
        mpfr_sub (result->value.real, x->value.real, y->value.real,
                  GFC_RND_MODE);
      else
        mpfr_set_ui (result->value.real, 0, GFC_RND_MODE);
 
      break;
 
    default:
      gfc_internal_error ("gfc_simplify_dim(): Bad type");
    }
 
  return range_check (result, "DIM");
}
 
 
gfc_expr*
gfc_simplify_dot_product (gfc_expr *vector_a, gfc_expr *vector_b)
{
  gfc_expr *result;
 
  if (!is_constant_array_expr (vector_a)
      || !is_constant_array_expr (vector_b))
    return NULL;
 
  gcc_assert (vector_a->rank == 1);
  gcc_assert (vector_b->rank == 1);
  gcc_assert (gfc_compare_types (&vector_a->ts, &vector_b->ts));
 
  if (vector_a->value.constructor && vector_b->value.constructor)
    return compute_dot_product (vector_a->value.constructor, 1,
                                vector_b->value.constructor, 1);
 
  /* Zero sized array ...  */
  result = gfc_constant_result (vector_a->ts.type,
                                vector_a->ts.kind,
                                &vector_a->where);
  init_result_expr (result, 0, NULL);
  return result;
}
 
 
gfc_expr *
gfc_simplify_dprod (gfc_expr *x, gfc_expr *y)
{
  gfc_expr *a1, *a2, *result;
 
  if (x->expr_type != EXPR_CONSTANT || y->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (BT_REAL, gfc_default_double_kind, &x->where);
 
  a1 = gfc_real2real (x, gfc_default_double_kind);
  a2 = gfc_real2real (y, gfc_default_double_kind);
 
  mpfr_mul (result->value.real, a1->value.real, a2->value.real, GFC_RND_MODE);
 
  gfc_free_expr (a1);
  gfc_free_expr (a2);
 
  return range_check (result, "DPROD");
}
 
 
gfc_expr *
gfc_simplify_erf (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
 
  mpfr_erf (result->value.real, x->value.real, GFC_RND_MODE);
 
  return range_check (result, "ERF");
}
 
 
gfc_expr *
gfc_simplify_erfc (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
 
  mpfr_erfc (result->value.real, x->value.real, GFC_RND_MODE);
 
  return range_check (result, "ERFC");
}
 
 
/* Helper functions to simplify ERFC_SCALED(x) = ERFC(x) * EXP(X**2).  */
 
#define MAX_ITER 200
#define ARG_LIMIT 12
 
/* Calculate ERFC_SCALED directly by its definition:
 
     ERFC_SCALED(x) = ERFC(x) * EXP(X**2)
 
   using a large precision for intermediate results.  This is used for all
   but large values of the argument.  */
static void
fullprec_erfc_scaled (mpfr_t res, mpfr_t arg)
{
  mp_prec_t prec;
  mpfr_t a, b;
 
  prec = mpfr_get_default_prec ();
  mpfr_set_default_prec (10 * prec);
 
  mpfr_init (a);
  mpfr_init (b);
 
  mpfr_set (a, arg, GFC_RND_MODE);
  mpfr_sqr (b, a, GFC_RND_MODE);
  mpfr_exp (b, b, GFC_RND_MODE);
  mpfr_erfc (a, a, GFC_RND_MODE);
  mpfr_mul (a, a, b, GFC_RND_MODE);
 
  mpfr_set (res, a, GFC_RND_MODE);
  mpfr_set_default_prec (prec);
 
  mpfr_clear (a);
  mpfr_clear (b);
}
 
/* Calculate ERFC_SCALED using a power series expansion in 1/arg:
 
    ERFC_SCALED(x) = 1 / (x * sqrt(pi))
                     * (1 + Sum_n (-1)**n * (1 * 3 * 5 * ... * (2n-1))
                                          / (2 * x**2)**n)
 
  This is used for large values of the argument.  Intermediate calculations
  are performed with twice the precision.  We don't do a fixed number of
  iterations of the sum, but stop when it has converged to the required
  precision.  */
static void
asympt_erfc_scaled (mpfr_t res, mpfr_t arg)
{
  mpfr_t sum, x, u, v, w, oldsum, sumtrunc;
  mpz_t num;
  mp_prec_t prec;
  unsigned i;
 
  prec = mpfr_get_default_prec ();
  mpfr_set_default_prec (2 * prec);
 
  mpfr_init (sum);
  mpfr_init (x);
  mpfr_init (u);
  mpfr_init (v);
  mpfr_init (w);
  mpz_init (num);
 
  mpfr_init (oldsum);
  mpfr_init (sumtrunc);
  mpfr_set_prec (oldsum, prec);
  mpfr_set_prec (sumtrunc, prec);
 
  mpfr_set (x, arg, GFC_RND_MODE);
  mpfr_set_ui (sum, 1, GFC_RND_MODE);
  mpz_set_ui (num, 1);
 
  mpfr_set (u, x, GFC_RND_MODE);
  mpfr_sqr (u, u, GFC_RND_MODE);
  mpfr_mul_ui (u, u, 2, GFC_RND_MODE);
  mpfr_pow_si (u, u, -1, GFC_RND_MODE);
 
  for (i = 1; i < MAX_ITER; i++)
  {
    mpfr_set (oldsum, sum, GFC_RND_MODE);
 
    mpz_mul_ui (num, num, 2 * i - 1);
    mpz_neg (num, num);
 
    mpfr_set (w, u, GFC_RND_MODE);
    mpfr_pow_ui (w, w, i, GFC_RND_MODE);
 
    mpfr_set_z (v, num, GFC_RND_MODE);
    mpfr_mul (v, v, w, GFC_RND_MODE);
 
    mpfr_add (sum, sum, v, GFC_RND_MODE);
 
    mpfr_set (sumtrunc, sum, GFC_RND_MODE);
    if (mpfr_cmp (sumtrunc, oldsum) == 0)
      break;
  }
 
  /* We should have converged by now; otherwise, ARG_LIMIT is probably
     set too low.  */
  gcc_assert (i < MAX_ITER);
 
  /* Divide by x * sqrt(Pi).  */
  mpfr_const_pi (u, GFC_RND_MODE);
  mpfr_sqrt (u, u, GFC_RND_MODE);
  mpfr_mul (u, u, x, GFC_RND_MODE);
  mpfr_div (sum, sum, u, GFC_RND_MODE);
 
  mpfr_set (res, sum, GFC_RND_MODE);
  mpfr_set_default_prec (prec);
 
  mpfr_clears (sum, x, u, v, w, oldsum, sumtrunc, NULL);
  mpz_clear (num);
}
 
 
gfc_expr *
gfc_simplify_erfc_scaled (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
  if (mpfr_cmp_d (x->value.real, ARG_LIMIT) >= 0)
    asympt_erfc_scaled (result->value.real, x->value.real);
  else
    fullprec_erfc_scaled (result->value.real, x->value.real);
 
  return range_check (result, "ERFC_SCALED");
}
 
#undef MAX_ITER
#undef ARG_LIMIT
 
 
gfc_expr *
gfc_simplify_epsilon (gfc_expr *e)
{
  gfc_expr *result;
  int i;
 
  i = gfc_validate_kind (e->ts.type, e->ts.kind, false);
 
  result = gfc_constant_result (BT_REAL, e->ts.kind, &e->where);
 
  mpfr_set (result->value.real, gfc_real_kinds[i].epsilon, GFC_RND_MODE);
 
  return range_check (result, "EPSILON");
}
 
 
gfc_expr *
gfc_simplify_exp (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
 
  switch (x->ts.type)
    {
    case BT_REAL:
      mpfr_exp (result->value.real, x->value.real, GFC_RND_MODE);
      break;
 
    case BT_COMPLEX:
      gfc_set_model_kind (x->ts.kind);
      mpc_exp (result->value.complex, x->value.complex, GFC_MPC_RND_MODE);
      break;
 
    default:
      gfc_internal_error ("in gfc_simplify_exp(): Bad type");
    }
 
  return range_check (result, "EXP");
}
 
gfc_expr *
gfc_simplify_exponent (gfc_expr *x)
{
  int i;
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (BT_INTEGER, gfc_default_integer_kind,
                                &x->where);
 
  gfc_set_model (x->value.real);
 
  if (mpfr_sgn (x->value.real) == 0)
    {
      mpz_set_ui (result->value.integer, 0);
      return result;
    }
 
  i = (int) mpfr_get_exp (x->value.real);
  mpz_set_si (result->value.integer, i);
 
  return range_check (result, "EXPONENT");
}
 
 
gfc_expr *
gfc_simplify_float (gfc_expr *a)
{
  gfc_expr *result;
 
  if (a->expr_type != EXPR_CONSTANT)
    return NULL;
 
  if (a->is_boz)
    {
      gfc_typespec ts;
      gfc_clear_ts (&ts);
 
      ts.type = BT_REAL;
      ts.kind = gfc_default_real_kind;
 
      result = gfc_copy_expr (a);
      if (!gfc_convert_boz (result, &ts))
        {
          gfc_free_expr (result);
          return &gfc_bad_expr;
        }
    }
  else
    result = gfc_int2real (a, gfc_default_real_kind);
  return range_check (result, "FLOAT");
}
 
 
gfc_expr *
gfc_simplify_floor (gfc_expr *e, gfc_expr *k)
{
  gfc_expr *result;
  mpfr_t floor;
  int kind;
 
  kind = get_kind (BT_INTEGER, k, "FLOOR", gfc_default_integer_kind);
  if (kind == -1)
    gfc_internal_error ("gfc_simplify_floor(): Bad kind");
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (BT_INTEGER, kind, &e->where);
 
  gfc_set_model_kind (kind);
  mpfr_init (floor);
  mpfr_floor (floor, e->value.real);
 
  gfc_mpfr_to_mpz (result->value.integer, floor, &e->where);
 
  mpfr_clear (floor);
 
  return range_check (result, "FLOOR");
}
 
 
gfc_expr *
gfc_simplify_fraction (gfc_expr *x)
{
  gfc_expr *result;
  mpfr_t absv, exp, pow2;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (BT_REAL, x->ts.kind, &x->where);
 
  if (mpfr_sgn (x->value.real) == 0)
    {
      mpfr_set_ui (result->value.real, 0, GFC_RND_MODE);
      return result;
    }
 
  gfc_set_model_kind (x->ts.kind);
  mpfr_init (exp);
  mpfr_init (absv);
  mpfr_init (pow2);
 
  mpfr_abs (absv, x->value.real, GFC_RND_MODE);
  mpfr_log2 (exp, absv, GFC_RND_MODE);
 
  mpfr_trunc (exp, exp);
  mpfr_add_ui (exp, exp, 1, GFC_RND_MODE);
 
  mpfr_ui_pow (pow2, 2, exp, GFC_RND_MODE);
 
  mpfr_div (result->value.real, absv, pow2, GFC_RND_MODE);
 
  mpfr_clears (exp, absv, pow2, NULL);
 
  return range_check (result, "FRACTION");
}
 
 
gfc_expr *
gfc_simplify_gamma (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
 
  mpfr_gamma (result->value.real, x->value.real, GFC_RND_MODE);
 
  return range_check (result, "GAMMA");
}
 
 
gfc_expr *
gfc_simplify_huge (gfc_expr *e)
{
  gfc_expr *result;
  int i;
 
  i = gfc_validate_kind (e->ts.type, e->ts.kind, false);
 
  result = gfc_constant_result (e->ts.type, e->ts.kind, &e->where);
 
  switch (e->ts.type)
    {
    case BT_INTEGER:
      mpz_set (result->value.integer, gfc_integer_kinds[i].huge);
      break;
 
    case BT_REAL:
      mpfr_set (result->value.real, gfc_real_kinds[i].huge, GFC_RND_MODE);
      break;
 
    default:
      gcc_unreachable ();
    }
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_hypot (gfc_expr *x, gfc_expr *y)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT || y->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
  mpfr_hypot (result->value.real, x->value.real, y->value.real, GFC_RND_MODE);
  return range_check (result, "HYPOT");
}
 
 
/* We use the processor's collating sequence, because all
   systems that gfortran currently works on are ASCII.  */
 
gfc_expr *
gfc_simplify_iachar (gfc_expr *e, gfc_expr *kind)
{
  gfc_expr *result;
  gfc_char_t index;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  if (e->value.character.length != 1)
    {
      gfc_error ("Argument of IACHAR at %L must be of length one", &e->where);
      return &gfc_bad_expr;
    }
 
  index = e->value.character.string[0];
 
  if (gfc_option.warn_surprising && index > 127)
    gfc_warning ("Argument of IACHAR function at %L outside of range 0..127",
                 &e->where);
 
  if ((result = int_expr_with_kind (index, kind, "IACHAR")) == NULL)
    return &gfc_bad_expr;
 
  result->where = e->where;
 
  return range_check (result, "IACHAR");
}
 
 
gfc_expr *
gfc_simplify_iand (gfc_expr *x, gfc_expr *y)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT || y->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (BT_INTEGER, x->ts.kind, &x->where);
 
  mpz_and (result->value.integer, x->value.integer, y->value.integer);
 
  return range_check (result, "IAND");
}
 
 
gfc_expr *
gfc_simplify_ibclr (gfc_expr *x, gfc_expr *y)
{
  gfc_expr *result;
  int k, pos;
 
  if (x->expr_type != EXPR_CONSTANT || y->expr_type != EXPR_CONSTANT)
    return NULL;
 
  if (gfc_extract_int (y, &pos) != NULL || pos < 0)
    {
      gfc_error ("Invalid second argument of IBCLR at %L", &y->where);
      return &gfc_bad_expr;
    }
 
  k = gfc_validate_kind (x->ts.type, x->ts.kind, false);
 
  if (pos >= gfc_integer_kinds[k].bit_size)
    {
      gfc_error ("Second argument of IBCLR exceeds bit size at %L",
                 &y->where);
      return &gfc_bad_expr;
    }
 
  result = gfc_copy_expr (x);
 
  convert_mpz_to_unsigned (result->value.integer,
                           gfc_integer_kinds[k].bit_size);
 
  mpz_clrbit (result->value.integer, pos);
 
  convert_mpz_to_signed (result->value.integer,
                         gfc_integer_kinds[k].bit_size);
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_ibits (gfc_expr *x, gfc_expr *y, gfc_expr *z)
{
  gfc_expr *result;
  int pos, len;
  int i, k, bitsize;
  int *bits;
 
  if (x->expr_type != EXPR_CONSTANT
      || y->expr_type != EXPR_CONSTANT
      || z->expr_type != EXPR_CONSTANT)
    return NULL;
 
  if (gfc_extract_int (y, &pos) != NULL || pos < 0)
    {
      gfc_error ("Invalid second argument of IBITS at %L", &y->where);
      return &gfc_bad_expr;
    }
 
  if (gfc_extract_int (z, &len) != NULL || len < 0)
    {
      gfc_error ("Invalid third argument of IBITS at %L", &z->where);
      return &gfc_bad_expr;
    }
 
  k = gfc_validate_kind (BT_INTEGER, x->ts.kind, false);
 
  bitsize = gfc_integer_kinds[k].bit_size;
 
  if (pos + len > bitsize)
    {
      gfc_error ("Sum of second and third arguments of IBITS exceeds "
                 "bit size at %L", &y->where);
      return &gfc_bad_expr;
    }
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
  convert_mpz_to_unsigned (result->value.integer,
                           gfc_integer_kinds[k].bit_size);
 
  bits = XCNEWVEC (int, bitsize);
 
  for (i = 0; i < bitsize; i++)
    bits[i] = 0;
 
  for (i = 0; i < len; i++)
    bits[i] = mpz_tstbit (x->value.integer, i + pos);
 
  for (i = 0; i < bitsize; i++)
    {
      if (bits[i] == 0)
        mpz_clrbit (result->value.integer, i);
      else if (bits[i] == 1)
        mpz_setbit (result->value.integer, i);
      else
        gfc_internal_error ("IBITS: Bad bit");
    }
 
  gfc_free (bits);
 
  convert_mpz_to_signed (result->value.integer,
                         gfc_integer_kinds[k].bit_size);
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_ibset (gfc_expr *x, gfc_expr *y)
{
  gfc_expr *result;
  int k, pos;
 
  if (x->expr_type != EXPR_CONSTANT || y->expr_type != EXPR_CONSTANT)
    return NULL;
 
  if (gfc_extract_int (y, &pos) != NULL || pos < 0)
    {
      gfc_error ("Invalid second argument of IBSET at %L", &y->where);
      return &gfc_bad_expr;
    }
 
  k = gfc_validate_kind (x->ts.type, x->ts.kind, false);
 
  if (pos >= gfc_integer_kinds[k].bit_size)
    {
      gfc_error ("Second argument of IBSET exceeds bit size at %L",
                 &y->where);
      return &gfc_bad_expr;
    }
 
  result = gfc_copy_expr (x);
 
  convert_mpz_to_unsigned (result->value.integer,
                           gfc_integer_kinds[k].bit_size);
 
  mpz_setbit (result->value.integer, pos);
 
  convert_mpz_to_signed (result->value.integer,
                         gfc_integer_kinds[k].bit_size);
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_ichar (gfc_expr *e, gfc_expr *kind)
{
  gfc_expr *result;
  gfc_char_t index;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  if (e->value.character.length != 1)
    {
      gfc_error ("Argument of ICHAR at %L must be of length one", &e->where);
      return &gfc_bad_expr;
    }
 
  index = e->value.character.string[0];
 
  if ((result = int_expr_with_kind (index, kind, "ICHAR")) == NULL)
    return &gfc_bad_expr;
 
  result->where = e->where;
  return range_check (result, "ICHAR");
}
 
 
gfc_expr *
gfc_simplify_ieor (gfc_expr *x, gfc_expr *y)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT || y->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (BT_INTEGER, x->ts.kind, &x->where);
 
  mpz_xor (result->value.integer, x->value.integer, y->value.integer);
 
  return range_check (result, "IEOR");
}
 
 
gfc_expr *
gfc_simplify_index (gfc_expr *x, gfc_expr *y, gfc_expr *b, gfc_expr *kind)
{
  gfc_expr *result;
  int back, len, lensub;
  int i, j, k, count, index = 0, start;
 
  if (x->expr_type != EXPR_CONSTANT || y->expr_type != EXPR_CONSTANT
      || ( b != NULL && b->expr_type !=  EXPR_CONSTANT))
    return NULL;
 
  if (b != NULL && b->value.logical != 0)
    back = 1;
  else
    back = 0;
 
  k = get_kind (BT_INTEGER, kind, "INDEX", gfc_default_integer_kind);
  if (k == -1)
    return &gfc_bad_expr;
 
  result = gfc_constant_result (BT_INTEGER, k, &x->where);
 
  len = x->value.character.length;
  lensub = y->value.character.length;
 
  if (len < lensub)
    {
      mpz_set_si (result->value.integer, 0);
      return result;
    }
 
  if (back == 0)
    {
      if (lensub == 0)
        {
          mpz_set_si (result->value.integer, 1);
          return result;
        }
      else if (lensub == 1)
        {
          for (i = 0; i < len; i++)
            {
              for (j = 0; j < lensub; j++)
                {
                  if (y->value.character.string[j]
                      == x->value.character.string[i])
                    {
                      index = i + 1;
                      goto done;
                    }
                }
            }
        }
      else
        {
          for (i = 0; i < len; i++)
            {
              for (j = 0; j < lensub; j++)
                {
                  if (y->value.character.string[j]
                      == x->value.character.string[i])
                    {
                      start = i;
                      count = 0;
 
                      for (k = 0; k < lensub; k++)
                        {
                          if (y->value.character.string[k]
                              == x->value.character.string[k + start])
                            count++;
                        }
 
                      if (count == lensub)
                        {
                          index = start + 1;
                          goto done;
                        }
                    }
                }
            }
        }
 
    }
  else
    {
      if (lensub == 0)
        {
          mpz_set_si (result->value.integer, len + 1);
          return result;
        }
      else if (lensub == 1)
        {
          for (i = 0; i < len; i++)
            {
              for (j = 0; j < lensub; j++)
                {
                  if (y->value.character.string[j]
                      == x->value.character.string[len - i])
                    {
                      index = len - i + 1;
                      goto done;
                    }
                }
            }
        }
      else
        {
          for (i = 0; i < len; i++)
            {
              for (j = 0; j < lensub; j++)
                {
                  if (y->value.character.string[j]
                      == x->value.character.string[len - i])
                    {
                      start = len - i;
                      if (start <= len - lensub)
                        {
                          count = 0;
                          for (k = 0; k < lensub; k++)
                            if (y->value.character.string[k]
                                == x->value.character.string[k + start])
                              count++;
 
                          if (count == lensub)
                            {
                              index = start + 1;
                              goto done;
                            }
                        }
                      else
                        {
                          continue;
                        }
                    }
                }
            }
        }
    }
 
done:
  mpz_set_si (result->value.integer, index);
  return range_check (result, "INDEX");
}
 
 
gfc_expr *
gfc_simplify_int (gfc_expr *e, gfc_expr *k)
{
  gfc_expr *result = NULL;
  int kind;
 
  kind = get_kind (BT_INTEGER, k, "INT", gfc_default_integer_kind);
  if (kind == -1)
    return &gfc_bad_expr;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  switch (e->ts.type)
    {
    case BT_INTEGER:
      result = gfc_int2int (e, kind);
      break;
 
    case BT_REAL:
      result = gfc_real2int (e, kind);
      break;
 
    case BT_COMPLEX:
      result = gfc_complex2int (e, kind);
      break;
 
    default:
      gfc_error ("Argument of INT at %L is not a valid type", &e->where);
      return &gfc_bad_expr;
    }
 
  return range_check (result, "INT");
}
 
 
static gfc_expr *
simplify_intconv (gfc_expr *e, int kind, const char *name)
{
  gfc_expr *result = NULL;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  switch (e->ts.type)
    {
    case BT_INTEGER:
      result = gfc_int2int (e, kind);
      break;
 
    case BT_REAL:
      result = gfc_real2int (e, kind);
      break;
 
    case BT_COMPLEX:
      result = gfc_complex2int (e, kind);
      break;
 
    default:
      gfc_error ("Argument of %s at %L is not a valid type", name, &e->where);
      return &gfc_bad_expr;
    }
 
  return range_check (result, name);
}
 
 
gfc_expr *
gfc_simplify_int2 (gfc_expr *e)
{
  return simplify_intconv (e, 2, "INT2");
}
 
 
gfc_expr *
gfc_simplify_int8 (gfc_expr *e)
{
  return simplify_intconv (e, 8, "INT8");
}
 
 
gfc_expr *
gfc_simplify_long (gfc_expr *e)
{
  return simplify_intconv (e, 4, "LONG");
}
 
 
gfc_expr *
gfc_simplify_ifix (gfc_expr *e)
{
  gfc_expr *rtrunc, *result;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (BT_INTEGER, gfc_default_integer_kind,
                                &e->where);
 
  rtrunc = gfc_copy_expr (e);
 
  mpfr_trunc (rtrunc->value.real, e->value.real);
  gfc_mpfr_to_mpz (result->value.integer, rtrunc->value.real, &e->where);
 
  gfc_free_expr (rtrunc);
  return range_check (result, "IFIX");
}
 
 
gfc_expr *
gfc_simplify_idint (gfc_expr *e)
{
  gfc_expr *rtrunc, *result;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (BT_INTEGER, gfc_default_integer_kind,
                                &e->where);
 
  rtrunc = gfc_copy_expr (e);
 
  mpfr_trunc (rtrunc->value.real, e->value.real);
  gfc_mpfr_to_mpz (result->value.integer, rtrunc->value.real, &e->where);
 
  gfc_free_expr (rtrunc);
  return range_check (result, "IDINT");
}
 
 
gfc_expr *
gfc_simplify_ior (gfc_expr *x, gfc_expr *y)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT || y->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (BT_INTEGER, x->ts.kind, &x->where);
 
  mpz_ior (result->value.integer, x->value.integer, y->value.integer);
  return range_check (result, "IOR");
}
 
 
gfc_expr *
gfc_simplify_is_iostat_end (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (BT_LOGICAL, gfc_default_logical_kind,
                                &x->where);
  result->value.logical = (mpz_cmp_si (x->value.integer, LIBERROR_END) == 0);
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_is_iostat_eor (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (BT_LOGICAL, gfc_default_logical_kind,
                                &x->where);
  result->value.logical = (mpz_cmp_si (x->value.integer, LIBERROR_EOR) == 0);
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_isnan (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (BT_LOGICAL, gfc_default_logical_kind,
                                &x->where);
  result->value.logical = mpfr_nan_p (x->value.real);
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_ishft (gfc_expr *e, gfc_expr *s)
{
  gfc_expr *result;
  int shift, ashift, isize, k, *bits, i;
 
  if (e->expr_type != EXPR_CONSTANT || s->expr_type != EXPR_CONSTANT)
    return NULL;
 
  if (gfc_extract_int (s, &shift) != NULL)
    {
      gfc_error ("Invalid second argument of ISHFT at %L", &s->where);
      return &gfc_bad_expr;
    }
 
  k = gfc_validate_kind (BT_INTEGER, e->ts.kind, false);
 
  isize = gfc_integer_kinds[k].bit_size;
 
  if (shift >= 0)
    ashift = shift;
  else
    ashift = -shift;
 
  if (ashift > isize)
    {
      gfc_error ("Magnitude of second argument of ISHFT exceeds bit size "
                 "at %L", &s->where);
      return &gfc_bad_expr;
    }
 
  result = gfc_constant_result (e->ts.type, e->ts.kind, &e->where);
 
  if (shift == 0)
    {
      mpz_set (result->value.integer, e->value.integer);
      return range_check (result, "ISHFT");
    }
 
  bits = XCNEWVEC (int, isize);
 
  for (i = 0; i < isize; i++)
    bits[i] = mpz_tstbit (e->value.integer, i);
 
  if (shift > 0)
    {
      for (i = 0; i < shift; i++)
        mpz_clrbit (result->value.integer, i);
 
      for (i = 0; i < isize - shift; i++)
        {
          if (bits[i] == 0)
            mpz_clrbit (result->value.integer, i + shift);
          else
            mpz_setbit (result->value.integer, i + shift);
        }
    }
  else
    {
      for (i = isize - 1; i >= isize - ashift; i--)
        mpz_clrbit (result->value.integer, i);
 
      for (i = isize - 1; i >= ashift; i--)
        {
          if (bits[i] == 0)
            mpz_clrbit (result->value.integer, i - ashift);
          else
            mpz_setbit (result->value.integer, i - ashift);
        }
    }
 
  convert_mpz_to_signed (result->value.integer, isize);
 
  gfc_free (bits);
  return result;
}
 
 
gfc_expr *
gfc_simplify_ishftc (gfc_expr *e, gfc_expr *s, gfc_expr *sz)
{
  gfc_expr *result;
  int shift, ashift, isize, ssize, delta, k;
  int i, *bits;
 
  if (e->expr_type != EXPR_CONSTANT || s->expr_type != EXPR_CONSTANT)
    return NULL;
 
  if (gfc_extract_int (s, &shift) != NULL)
    {
      gfc_error ("Invalid second argument of ISHFTC at %L", &s->where);
      return &gfc_bad_expr;
    }
 
  k = gfc_validate_kind (e->ts.type, e->ts.kind, false);
  isize = gfc_integer_kinds[k].bit_size;
 
  if (sz != NULL)
    {
      if (sz->expr_type != EXPR_CONSTANT)
        return NULL;
 
      if (gfc_extract_int (sz, &ssize) != NULL || ssize <= 0)
        {
          gfc_error ("Invalid third argument of ISHFTC at %L", &sz->where);
          return &gfc_bad_expr;
        }
 
      if (ssize > isize)
        {
          gfc_error ("Magnitude of third argument of ISHFTC exceeds "
                     "BIT_SIZE of first argument at %L", &s->where);
          return &gfc_bad_expr;
        }
    }
  else
    ssize = isize;
 
  if (shift >= 0)
    ashift = shift;
  else
    ashift = -shift;
 
  if (ashift > ssize)
    {
      if (sz != NULL)
        gfc_error ("Magnitude of second argument of ISHFTC exceeds "
                   "third argument at %L", &s->where);
      else
        gfc_error ("Magnitude of second argument of ISHFTC exceeds "
                   "BIT_SIZE of first argument at %L", &s->where);
      return &gfc_bad_expr;
    }
 
  result = gfc_constant_result (e->ts.type, e->ts.kind, &e->where);
 
  mpz_set (result->value.integer, e->value.integer);
 
  if (shift == 0)
    return result;
 
  convert_mpz_to_unsigned (result->value.integer, isize);
 
  bits = XCNEWVEC (int, ssize);
 
  for (i = 0; i < ssize; i++)
    bits[i] = mpz_tstbit (e->value.integer, i);
 
  delta = ssize - ashift;
 
  if (shift > 0)
    {
      for (i = 0; i < delta; i++)
        {
          if (bits[i] == 0)
            mpz_clrbit (result->value.integer, i + shift);
          else
            mpz_setbit (result->value.integer, i + shift);
        }
 
      for (i = delta; i < ssize; i++)
        {
          if (bits[i] == 0)
            mpz_clrbit (result->value.integer, i - delta);
          else
            mpz_setbit (result->value.integer, i - delta);
        }
    }
  else
    {
      for (i = 0; i < ashift; i++)
        {
          if (bits[i] == 0)
            mpz_clrbit (result->value.integer, i + delta);
          else
            mpz_setbit (result->value.integer, i + delta);
        }
 
      for (i = ashift; i < ssize; i++)
        {
          if (bits[i] == 0)
            mpz_clrbit (result->value.integer, i + shift);
          else
            mpz_setbit (result->value.integer, i + shift);
        }
    }
 
  convert_mpz_to_signed (result->value.integer, isize);
 
  gfc_free (bits);
  return result;
}
 
 
gfc_expr *
gfc_simplify_kind (gfc_expr *e)
{
 
  if (e->ts.type == BT_DERIVED)
    {
      gfc_error ("Argument of KIND at %L is a DERIVED type", &e->where);
      return &gfc_bad_expr;
    }
 
  return gfc_int_expr (e->ts.kind);
}
 
 
static gfc_expr *
simplify_bound_dim (gfc_expr *array, gfc_expr *kind, int d, int upper,
                    gfc_array_spec *as, gfc_ref *ref)
{
  gfc_expr *l, *u, *result;
  int k;
 
  /* The last dimension of an assumed-size array is special.  */
  if (d == as->rank && as->type == AS_ASSUMED_SIZE && !upper)
    {
      if (as->lower[d-1]->expr_type == EXPR_CONSTANT)
        return gfc_copy_expr (as->lower[d-1]);
      else
        return NULL;
    }
 
  k = get_kind (BT_INTEGER, kind, upper ? "UBOUND" : "LBOUND",
                gfc_default_integer_kind);
  if (k == -1)
    return &gfc_bad_expr;
 
  result = gfc_constant_result (BT_INTEGER, k, &array->where);
 
 
  /* Then, we need to know the extent of the given dimension.  */
  if (ref->u.ar.type == AR_FULL)
    {
      l = as->lower[d-1];
      u = as->upper[d-1];
 
      if (l->expr_type != EXPR_CONSTANT || u->expr_type != EXPR_CONSTANT)
        return NULL;
 
      if (mpz_cmp (l->value.integer, u->value.integer) > 0)
        {
          /* Zero extent.  */
          if (upper)
            mpz_set_si (result->value.integer, 0);
          else
            mpz_set_si (result->value.integer, 1);
        }
      else
        {
          /* Nonzero extent.  */
          if (upper)
            mpz_set (result->value.integer, u->value.integer);
          else
            mpz_set (result->value.integer, l->value.integer);
        }
    }
  else
    {
      if (upper)
        {
          if (gfc_ref_dimen_size (&ref->u.ar, d-1, &result->value.integer)
              != SUCCESS)
            return NULL;
        }
      else
        mpz_set_si (result->value.integer, (long int) 1);
    }
 
  return range_check (result, upper ? "UBOUND" : "LBOUND");
}
 
 
static gfc_expr *
simplify_bound (gfc_expr *array, gfc_expr *dim, gfc_expr *kind, int upper)
{
  gfc_ref *ref;
  gfc_array_spec *as;
  int d;
 
  if (array->expr_type != EXPR_VARIABLE)
    return NULL;
 
  /* Follow any component references.  */
  as = array->symtree->n.sym->as;
  for (ref = array->ref; ref; ref = ref->next)
    {
      switch (ref->type)
        {
        case REF_ARRAY:
          switch (ref->u.ar.type)
            {
            case AR_ELEMENT:
              as = NULL;
              continue;
 
            case AR_FULL:
              /* We're done because 'as' has already been set in the
                 previous iteration.  */
              if (!ref->next)
                goto done;
 
            /* Fall through.  */
 
            case AR_UNKNOWN:
              return NULL;
 
            case AR_SECTION:
              as = ref->u.ar.as;
              goto done;
            }
 
          gcc_unreachable ();
 
        case REF_COMPONENT:
          as = ref->u.c.component->as;
          continue;
 
        case REF_SUBSTRING:
          continue;
        }
    }
 
  gcc_unreachable ();
 
 done:
 
  if (as->type == AS_DEFERRED || as->type == AS_ASSUMED_SHAPE)
    return NULL;
 
  if (dim == NULL)
    {
      /* Multi-dimensional bounds.  */
      gfc_expr *bounds[GFC_MAX_DIMENSIONS];
      gfc_expr *e;
      gfc_constructor *head, *tail;
      int k;
 
      /* UBOUND(ARRAY) is not valid for an assumed-size array.  */
      if (upper && as->type == AS_ASSUMED_SIZE)
        {
          /* An error message will be emitted in
             check_assumed_size_reference (resolve.c).  */
          return &gfc_bad_expr;
        }
 
      /* Simplify the bounds for each dimension.  */
      for (d = 0; d < array->rank; d++)
        {
          bounds[d] = simplify_bound_dim (array, kind, d + 1, upper, as, ref);
          if (bounds[d] == NULL || bounds[d] == &gfc_bad_expr)
            {
              int j;
 
              for (j = 0; j < d; j++)
                gfc_free_expr (bounds[j]);
              return bounds[d];
            }
        }
 
      /* Allocate the result expression.  */
      e = gfc_get_expr ();
      e->where = array->where;
      e->expr_type = EXPR_ARRAY;
      e->ts.type = BT_INTEGER;
      k = get_kind (BT_INTEGER, kind, upper ? "UBOUND" : "LBOUND",
                    gfc_default_integer_kind);
      if (k == -1)
        {
          gfc_free_expr (e);
          return &gfc_bad_expr;
        }
      e->ts.kind = k;
 
      /* The result is a rank 1 array; its size is the rank of the first
         argument to {L,U}BOUND.  */
      e->rank = 1;
      e->shape = gfc_get_shape (1);
      mpz_init_set_ui (e->shape[0], array->rank);
 
      /* Create the constructor for this array.  */
      head = tail = NULL;
      for (d = 0; d < array->rank; d++)
        {
          /* Get a new constructor element.  */
          if (head == NULL)
            head = tail = gfc_get_constructor ();
          else
            {
              tail->next = gfc_get_constructor ();
              tail = tail->next;
            }
 
          tail->where = e->where;
          tail->expr = bounds[d];
        }
      e->value.constructor = head;
 
      return e;
    }
  else
    {
      /* A DIM argument is specified.  */
      if (dim->expr_type != EXPR_CONSTANT)
        return NULL;
 
      d = mpz_get_si (dim->value.integer);
 
      if (d < 1 || d > as->rank
          || (d == as->rank && as->type == AS_ASSUMED_SIZE && upper))
        {
          gfc_error ("DIM argument at %L is out of bounds", &dim->where);
          return &gfc_bad_expr;
        }
 
      return simplify_bound_dim (array, kind, d, upper, as, ref);
    }
}
 
 
gfc_expr *
gfc_simplify_lbound (gfc_expr *array, gfc_expr *dim, gfc_expr *kind)
{
  return simplify_bound (array, dim, kind, 0);
}
 
 
gfc_expr *
gfc_simplify_leadz (gfc_expr *e)
{
  gfc_expr *result;
  unsigned long lz, bs;
  int i;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  i = gfc_validate_kind (e->ts.type, e->ts.kind, false);
  bs = gfc_integer_kinds[i].bit_size;
  if (mpz_cmp_si (e->value.integer, 0) == 0)
    lz = bs;
  else if (mpz_cmp_si (e->value.integer, 0) < 0)
    lz = 0;
  else
    lz = bs - mpz_sizeinbase (e->value.integer, 2);
 
  result = gfc_constant_result (BT_INTEGER, gfc_default_integer_kind,
                                &e->where);
  mpz_set_ui (result->value.integer, lz);
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_len (gfc_expr *e, gfc_expr *kind)
{
  gfc_expr *result;
  int k = get_kind (BT_INTEGER, kind, "LEN", gfc_default_integer_kind);
 
  if (k == -1)
    return &gfc_bad_expr;
 
  if (e->expr_type == EXPR_CONSTANT)
    {
      result = gfc_constant_result (BT_INTEGER, k, &e->where);
      mpz_set_si (result->value.integer, e->value.character.length);
      if (gfc_range_check (result) == ARITH_OK)
        return result;
      else
        {
          gfc_free_expr (result);
          return NULL;
        }
    }
 
  if (e->ts.u.cl != NULL && e->ts.u.cl->length != NULL
      && e->ts.u.cl->length->expr_type == EXPR_CONSTANT
      && e->ts.u.cl->length->ts.type == BT_INTEGER)
    {
      result = gfc_constant_result (BT_INTEGER, k, &e->where);
      mpz_set (result->value.integer, e->ts.u.cl->length->value.integer);
      if (gfc_range_check (result) == ARITH_OK)
        return result;
      else
        {
          gfc_free_expr (result);
          return NULL;
        }
    }
 
  return NULL;
}
 
 
gfc_expr *
gfc_simplify_len_trim (gfc_expr *e, gfc_expr *kind)
{
  gfc_expr *result;
  int count, len, lentrim, i;
  int k = get_kind (BT_INTEGER, kind, "LEN_TRIM", gfc_default_integer_kind);
 
  if (k == -1)
    return &gfc_bad_expr;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (BT_INTEGER, k, &e->where);
  len = e->value.character.length;
 
  for (count = 0, i = 1; i <= len; i++)
    if (e->value.character.string[len - i] == ' ')
      count++;
    else
      break;
 
  lentrim = len - count;
 
  mpz_set_si (result->value.integer, lentrim);
  return range_check (result, "LEN_TRIM");
}
 
gfc_expr *
gfc_simplify_lgamma (gfc_expr *x ATTRIBUTE_UNUSED)
{
  gfc_expr *result;
  int sg;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
 
  mpfr_lgamma (result->value.real, &sg, x->value.real, GFC_RND_MODE);
 
  return range_check (result, "LGAMMA");
}
 
 
gfc_expr *
gfc_simplify_lge (gfc_expr *a, gfc_expr *b)
{
  if (a->expr_type != EXPR_CONSTANT || b->expr_type != EXPR_CONSTANT)
    return NULL;
 
  return gfc_logical_expr (gfc_compare_string (a, b) >= 0, &a->where);
}
 
 
gfc_expr *
gfc_simplify_lgt (gfc_expr *a, gfc_expr *b)
{
  if (a->expr_type != EXPR_CONSTANT || b->expr_type != EXPR_CONSTANT)
    return NULL;
 
  return gfc_logical_expr (gfc_compare_string (a, b) > 0,
                           &a->where);
}
 
 
gfc_expr *
gfc_simplify_lle (gfc_expr *a, gfc_expr *b)
{
  if (a->expr_type != EXPR_CONSTANT || b->expr_type != EXPR_CONSTANT)
    return NULL;
 
  return gfc_logical_expr (gfc_compare_string (a, b) <= 0, &a->where);
}
 
 
gfc_expr *
gfc_simplify_llt (gfc_expr *a, gfc_expr *b)
{
  if (a->expr_type != EXPR_CONSTANT || b->expr_type != EXPR_CONSTANT)
    return NULL;
 
  return gfc_logical_expr (gfc_compare_string (a, b) < 0, &a->where);
}
 
 
gfc_expr *
gfc_simplify_log (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
 
 
  switch (x->ts.type)
    {
    case BT_REAL:
      if (mpfr_sgn (x->value.real) <= 0)
        {
          gfc_error ("Argument of LOG at %L cannot be less than or equal "
                     "to zero", &x->where);
          gfc_free_expr (result);
          return &gfc_bad_expr;
        }
 
      mpfr_log (result->value.real, x->value.real, GFC_RND_MODE);
      break;
 
    case BT_COMPLEX:
      if ((mpfr_sgn (mpc_realref (x->value.complex)) == 0)
          && (mpfr_sgn (mpc_imagref (x->value.complex)) == 0))
        {
          gfc_error ("Complex argument of LOG at %L cannot be zero",
                     &x->where);
          gfc_free_expr (result);
          return &gfc_bad_expr;
        }
 
      gfc_set_model_kind (x->ts.kind);
      mpc_log (result->value.complex, x->value.complex, GFC_MPC_RND_MODE);
      break;
 
    default:
      gfc_internal_error ("gfc_simplify_log: bad type");
    }
 
  return range_check (result, "LOG");
}
 
 
gfc_expr *
gfc_simplify_log10 (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  if (mpfr_sgn (x->value.real) <= 0)
    {
      gfc_error ("Argument of LOG10 at %L cannot be less than or equal "
                 "to zero", &x->where);
      return &gfc_bad_expr;
    }
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
 
  mpfr_log10 (result->value.real, x->value.real, GFC_RND_MODE);
 
  return range_check (result, "LOG10");
}
 
 
gfc_expr *
gfc_simplify_logical (gfc_expr *e, gfc_expr *k)
{
  gfc_expr *result;
  int kind;
 
  kind = get_kind (BT_LOGICAL, k, "LOGICAL", gfc_default_logical_kind);
  if (kind < 0)
    return &gfc_bad_expr;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (BT_LOGICAL, kind, &e->where);
 
  result->value.logical = e->value.logical;
 
  return result;
}
 
 
gfc_expr*
gfc_simplify_matmul (gfc_expr *matrix_a, gfc_expr *matrix_b)
{
  gfc_expr *result;
  gfc_constructor *ma_ctor, *mb_ctor;
  int row, result_rows, col, result_columns, stride_a, stride_b;
 
  if (!is_constant_array_expr (matrix_a)
      || !is_constant_array_expr (matrix_b))
    return NULL;
 
  gcc_assert (gfc_compare_types (&matrix_a->ts, &matrix_b->ts));
  result = gfc_start_constructor (matrix_a->ts.type,
                                  matrix_a->ts.kind,
                                  &matrix_a->where);
 
  if (matrix_a->rank == 1 && matrix_b->rank == 2)
    {
      result_rows = 1;
      result_columns = mpz_get_si (matrix_b->shape[0]);
      stride_a = 1;
      stride_b = mpz_get_si (matrix_b->shape[0]);
 
      result->rank = 1;
      result->shape = gfc_get_shape (result->rank);
      mpz_init_set_si (result->shape[0], result_columns);
    }
  else if (matrix_a->rank == 2 && matrix_b->rank == 1)
    {
      result_rows = mpz_get_si (matrix_b->shape[0]);
      result_columns = 1;
      stride_a = mpz_get_si (matrix_a->shape[0]);
      stride_b = 1;
 
      result->rank = 1;
      result->shape = gfc_get_shape (result->rank);
      mpz_init_set_si (result->shape[0], result_rows);
    }
  else if (matrix_a->rank == 2 && matrix_b->rank == 2)
    {
      result_rows = mpz_get_si (matrix_a->shape[0]);
      result_columns = mpz_get_si (matrix_b->shape[1]);
      stride_a = mpz_get_si (matrix_a->shape[1]);
      stride_b = mpz_get_si (matrix_b->shape[0]);
 
      result->rank = 2;
      result->shape = gfc_get_shape (result->rank);
      mpz_init_set_si (result->shape[0], result_rows);
      mpz_init_set_si (result->shape[1], result_columns);
    }
  else
    gcc_unreachable();
 
  ma_ctor = matrix_a->value.constructor;
  mb_ctor = matrix_b->value.constructor;
 
  for (col = 0; col < result_columns; ++col)
    {
      ma_ctor = matrix_a->value.constructor;
 
      for (row = 0; row < result_rows; ++row)
        {
          gfc_expr *e;
          e = compute_dot_product (ma_ctor, stride_a,
                                   mb_ctor, 1);
 
          gfc_append_constructor (result, e);
 
          ADVANCE (ma_ctor, 1);
        }
 
      ADVANCE (mb_ctor, stride_b);
    }
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_merge (gfc_expr *tsource, gfc_expr *fsource, gfc_expr *mask)
{
  if (tsource->expr_type != EXPR_CONSTANT
      || fsource->expr_type != EXPR_CONSTANT
      || mask->expr_type != EXPR_CONSTANT)
    return NULL;
 
  return gfc_copy_expr (mask->value.logical ? tsource : fsource);
}
 
 
/* Selects bewteen current value and extremum for simplify_min_max
   and simplify_minval_maxval.  */
static void
min_max_choose (gfc_expr *arg, gfc_expr *extremum, int sign)
{
  switch (arg->ts.type)
    {
      case BT_INTEGER:
        if (mpz_cmp (arg->value.integer,
                        extremum->value.integer) * sign > 0)
        mpz_set (extremum->value.integer, arg->value.integer);
        break;
 
      case BT_REAL:
        /* We need to use mpfr_min and mpfr_max to treat NaN properly.  */
        if (sign > 0)
          mpfr_max (extremum->value.real, extremum->value.real,
                      arg->value.real, GFC_RND_MODE);
        else
          mpfr_min (extremum->value.real, extremum->value.real,
                      arg->value.real, GFC_RND_MODE);
        break;
 
      case BT_CHARACTER:
#define LENGTH(x) ((x)->value.character.length)
#define STRING(x) ((x)->value.character.string)
        if (LENGTH(extremum) < LENGTH(arg))
          {
            gfc_char_t *tmp = STRING(extremum);
 
            STRING(extremum) = gfc_get_wide_string (LENGTH(arg) + 1);
            memcpy (STRING(extremum), tmp,
                      LENGTH(extremum) * sizeof (gfc_char_t));
            gfc_wide_memset (&STRING(extremum)[LENGTH(extremum)], ' ',
                               LENGTH(arg) - LENGTH(extremum));
            STRING(extremum)[LENGTH(arg)] = '\0';  /* For debugger  */
            LENGTH(extremum) = LENGTH(arg);
            gfc_free (tmp);
          }
 
        if (gfc_compare_string (arg, extremum) * sign > 0)
          {
            gfc_free (STRING(extremum));
            STRING(extremum) = gfc_get_wide_string (LENGTH(extremum) + 1);
            memcpy (STRING(extremum), STRING(arg),
                      LENGTH(arg) * sizeof (gfc_char_t));
            gfc_wide_memset (&STRING(extremum)[LENGTH(arg)], ' ',
                               LENGTH(extremum) - LENGTH(arg));
            STRING(extremum)[LENGTH(extremum)] = '\0';  /* For debugger  */
          }
#undef LENGTH
#undef STRING
        break;
 
      default:
        gfc_internal_error ("simplify_min_max(): Bad type in arglist");
    }
}
 
 
/* This function is special since MAX() can take any number of
   arguments.  The simplified expression is a rewritten version of the
   argument list containing at most one constant element.  Other
   constant elements are deleted.  Because the argument list has
   already been checked, this function always succeeds.  sign is 1 for
   MAX(), -1 for MIN().  */
 
static gfc_expr *
simplify_min_max (gfc_expr *expr, int sign)
{
  gfc_actual_arglist *arg, *last, *extremum;
  gfc_intrinsic_sym * specific;
 
  last = NULL;
  extremum = NULL;
  specific = expr->value.function.isym;
 
  arg = expr->value.function.actual;
 
  for (; arg; last = arg, arg = arg->next)
    {
      if (arg->expr->expr_type != EXPR_CONSTANT)
        continue;
 
      if (extremum == NULL)
        {
          extremum = arg;
          continue;
        }
 
      min_max_choose (arg->expr, extremum->expr, sign);
 
      /* Delete the extra constant argument.  */
      if (last == NULL)
        expr->value.function.actual = arg->next;
      else
        last->next = arg->next;
 
      arg->next = NULL;
      gfc_free_actual_arglist (arg);
      arg = last;
    }
 
  /* If there is one value left, replace the function call with the
     expression.  */
  if (expr->value.function.actual->next != NULL)
    return NULL;
 
  /* Convert to the correct type and kind.  */
  if (expr->ts.type != BT_UNKNOWN)
    return gfc_convert_constant (expr->value.function.actual->expr,
        expr->ts.type, expr->ts.kind);
 
  if (specific->ts.type != BT_UNKNOWN)
    return gfc_convert_constant (expr->value.function.actual->expr,
        specific->ts.type, specific->ts.kind);
 
  return gfc_copy_expr (expr->value.function.actual->expr);
}
 
 
gfc_expr *
gfc_simplify_min (gfc_expr *e)
{
  return simplify_min_max (e, -1);
}
 
 
gfc_expr *
gfc_simplify_max (gfc_expr *e)
{
  return simplify_min_max (e, 1);
}
 
 
/* This is a simplified version of simplify_min_max to provide
   simplification of minval and maxval for a vector.  */
 
static gfc_expr *
simplify_minval_maxval (gfc_expr *expr, int sign)
{
  gfc_constructor *ctr, *extremum;
  gfc_intrinsic_sym * specific;
 
  extremum = NULL;
  specific = expr->value.function.isym;
 
  ctr = expr->value.constructor;
 
  for (; ctr; ctr = ctr->next)
    {
      if (ctr->expr->expr_type != EXPR_CONSTANT)
        return NULL;
 
      if (extremum == NULL)
        {
          extremum = ctr;
          continue;
        }
 
      min_max_choose (ctr->expr, extremum->expr, sign);
     }
 
  if (extremum == NULL)
    return NULL;
 
  /* Convert to the correct type and kind.  */
  if (expr->ts.type != BT_UNKNOWN)
    return gfc_convert_constant (extremum->expr,
        expr->ts.type, expr->ts.kind);
 
  if (specific->ts.type != BT_UNKNOWN)
    return gfc_convert_constant (extremum->expr,
        specific->ts.type, specific->ts.kind);
 
  return gfc_copy_expr (extremum->expr);
}
 
 
gfc_expr *
gfc_simplify_minval (gfc_expr *array, gfc_expr* dim, gfc_expr *mask)
{
  if (array->expr_type != EXPR_ARRAY || array->rank != 1 || dim || mask)
    return NULL;
 
  return simplify_minval_maxval (array, -1);
}
 
 
gfc_expr *
gfc_simplify_maxval (gfc_expr *array, gfc_expr* dim, gfc_expr *mask)
{
  if (array->expr_type != EXPR_ARRAY || array->rank != 1 || dim || mask)
    return NULL;
  return simplify_minval_maxval (array, 1);
}
 
 
gfc_expr *
gfc_simplify_maxexponent (gfc_expr *x)
{
  gfc_expr *result;
  int i;
 
  i = gfc_validate_kind (BT_REAL, x->ts.kind, false);
 
  result = gfc_int_expr (gfc_real_kinds[i].max_exponent);
  result->where = x->where;
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_minexponent (gfc_expr *x)
{
  gfc_expr *result;
  int i;
 
  i = gfc_validate_kind (BT_REAL, x->ts.kind, false);
 
  result = gfc_int_expr (gfc_real_kinds[i].min_exponent);
  result->where = x->where;
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_mod (gfc_expr *a, gfc_expr *p)
{
  gfc_expr *result;
  mpfr_t tmp;
  int kind;
 
  if (a->expr_type != EXPR_CONSTANT || p->expr_type != EXPR_CONSTANT)
    return NULL;
 
  kind = a->ts.kind > p->ts.kind ? a->ts.kind : p->ts.kind;
  result = gfc_constant_result (a->ts.type, kind, &a->where);
 
  switch (a->ts.type)
    {
    case BT_INTEGER:
      if (mpz_cmp_ui (p->value.integer, 0) == 0)
        {
          /* Result is processor-dependent.  */
          gfc_error ("Second argument MOD at %L is zero", &a->where);
          gfc_free_expr (result);
          return &gfc_bad_expr;
        }
      mpz_tdiv_r (result->value.integer, a->value.integer, p->value.integer);
      break;
 
    case BT_REAL:
      if (mpfr_cmp_ui (p->value.real, 0) == 0)
        {
          /* Result is processor-dependent.  */
          gfc_error ("Second argument of MOD at %L is zero", &p->where);
          gfc_free_expr (result);
          return &gfc_bad_expr;
        }
 
      gfc_set_model_kind (kind);
      mpfr_init (tmp);
      mpfr_div (tmp, a->value.real, p->value.real, GFC_RND_MODE);
      mpfr_trunc (tmp, tmp);
      mpfr_mul (tmp, tmp, p->value.real, GFC_RND_MODE);
      mpfr_sub (result->value.real, a->value.real, tmp, GFC_RND_MODE);
      mpfr_clear (tmp);
      break;
 
    default:
      gfc_internal_error ("gfc_simplify_mod(): Bad arguments");
    }
 
  return range_check (result, "MOD");
}
 
 
gfc_expr *
gfc_simplify_modulo (gfc_expr *a, gfc_expr *p)
{
  gfc_expr *result;
  mpfr_t tmp;
  int kind;
 
  if (a->expr_type != EXPR_CONSTANT || p->expr_type != EXPR_CONSTANT)
    return NULL;
 
  kind = a->ts.kind > p->ts.kind ? a->ts.kind : p->ts.kind;
  result = gfc_constant_result (a->ts.type, kind, &a->where);
 
  switch (a->ts.type)
    {
    case BT_INTEGER:
      if (mpz_cmp_ui (p->value.integer, 0) == 0)
        {
          /* Result is processor-dependent. This processor just opts
             to not handle it at all.  */
          gfc_error ("Second argument of MODULO at %L is zero", &a->where);
          gfc_free_expr (result);
          return &gfc_bad_expr;
        }
      mpz_fdiv_r (result->value.integer, a->value.integer, p->value.integer);
 
      break;
 
    case BT_REAL:
      if (mpfr_cmp_ui (p->value.real, 0) == 0)
        {
          /* Result is processor-dependent.  */
          gfc_error ("Second argument of MODULO at %L is zero", &p->where);
          gfc_free_expr (result);
          return &gfc_bad_expr;
        }
 
      gfc_set_model_kind (kind);
      mpfr_init (tmp);
      mpfr_div (tmp, a->value.real, p->value.real, GFC_RND_MODE);
      mpfr_floor (tmp, tmp);
      mpfr_mul (tmp, tmp, p->value.real, GFC_RND_MODE);
      mpfr_sub (result->value.real, a->value.real, tmp, GFC_RND_MODE);
      mpfr_clear (tmp);
      break;
 
    default:
      gfc_internal_error ("gfc_simplify_modulo(): Bad arguments");
    }
 
  return range_check (result, "MODULO");
}
 
 
/* Exists for the sole purpose of consistency with other intrinsics.  */
gfc_expr *
gfc_simplify_mvbits (gfc_expr *f  ATTRIBUTE_UNUSED,
                     gfc_expr *fp ATTRIBUTE_UNUSED,
                     gfc_expr *l  ATTRIBUTE_UNUSED,
                     gfc_expr *to ATTRIBUTE_UNUSED,
                     gfc_expr *tp ATTRIBUTE_UNUSED)
{
  return NULL;
}
 
 
gfc_expr *
gfc_simplify_nearest (gfc_expr *x, gfc_expr *s)
{
  gfc_expr *result;
  mp_exp_t emin, emax;
  int kind;
 
  if (x->expr_type != EXPR_CONSTANT || s->expr_type != EXPR_CONSTANT)
    return NULL;
 
  if (mpfr_sgn (s->value.real) == 0)
    {
      gfc_error ("Second argument of NEAREST at %L shall not be zero",
                 &s->where);
      return &gfc_bad_expr;
    }
 
  result = gfc_copy_expr (x);
 
  /* Save current values of emin and emax.  */
  emin = mpfr_get_emin ();
  emax = mpfr_get_emax ();
 
  /* Set emin and emax for the current model number.  */
  kind = gfc_validate_kind (BT_REAL, x->ts.kind, 0);
  mpfr_set_emin ((mp_exp_t) gfc_real_kinds[kind].min_exponent -
                mpfr_get_prec(result->value.real) + 1);
  mpfr_set_emax ((mp_exp_t) gfc_real_kinds[kind].max_exponent - 1);
  mpfr_check_range (result->value.real, 0, GMP_RNDU);
 
  if (mpfr_sgn (s->value.real) > 0)
    {
      mpfr_nextabove (result->value.real);
      mpfr_subnormalize (result->value.real, 0, GMP_RNDU);
    }
  else
    {
      mpfr_nextbelow (result->value.real);
      mpfr_subnormalize (result->value.real, 0, GMP_RNDD);
    }
 
  mpfr_set_emin (emin);
  mpfr_set_emax (emax);
 
  /* Only NaN can occur. Do not use range check as it gives an
     error for denormal numbers.  */
  if (mpfr_nan_p (result->value.real) && gfc_option.flag_range_check)
    {
      gfc_error ("Result of NEAREST is NaN at %L", &result->where);
      gfc_free_expr (result);
      return &gfc_bad_expr;
    }
 
  return result;
}
 
 
static gfc_expr *
simplify_nint (const char *name, gfc_expr *e, gfc_expr *k)
{
  gfc_expr *itrunc, *result;
  int kind;
 
  kind = get_kind (BT_INTEGER, k, name, gfc_default_integer_kind);
  if (kind == -1)
    return &gfc_bad_expr;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (BT_INTEGER, kind, &e->where);
 
  itrunc = gfc_copy_expr (e);
 
  mpfr_round (itrunc->value.real, e->value.real);
 
  gfc_mpfr_to_mpz (result->value.integer, itrunc->value.real, &e->where);
 
  gfc_free_expr (itrunc);
 
  return range_check (result, name);
}
 
 
gfc_expr *
gfc_simplify_new_line (gfc_expr *e)
{
  gfc_expr *result;
 
  result = gfc_constant_result (BT_CHARACTER, e->ts.kind, &e->where);
  result->value.character.string = gfc_get_wide_string (2);
  result->value.character.length = 1;
  result->value.character.string[0] = '\n';
  result->value.character.string[1] = '\0';     /* For debugger */
  return result;
}
 
 
gfc_expr *
gfc_simplify_nint (gfc_expr *e, gfc_expr *k)
{
  return simplify_nint ("NINT", e, k);
}
 
 
gfc_expr *
gfc_simplify_idnint (gfc_expr *e)
{
  return simplify_nint ("IDNINT", e, NULL);
}
 
 
gfc_expr *
gfc_simplify_not (gfc_expr *e)
{
  gfc_expr *result;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (e->ts.type, e->ts.kind, &e->where);
 
  mpz_com (result->value.integer, e->value.integer);
 
  return range_check (result, "NOT");
}
 
 
gfc_expr *
gfc_simplify_null (gfc_expr *mold)
{
  gfc_expr *result;
 
  if (mold == NULL)
    {
      result = gfc_get_expr ();
      result->ts.type = BT_UNKNOWN;
    }
  else
    result = gfc_copy_expr (mold);
  result->expr_type = EXPR_NULL;
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_or (gfc_expr *x, gfc_expr *y)
{
  gfc_expr *result;
  int kind;
 
  if (x->expr_type != EXPR_CONSTANT || y->expr_type != EXPR_CONSTANT)
    return NULL;
 
  kind = x->ts.kind > y->ts.kind ? x->ts.kind : y->ts.kind;
  if (x->ts.type == BT_INTEGER)
    {
      result = gfc_constant_result (BT_INTEGER, kind, &x->where);
      mpz_ior (result->value.integer, x->value.integer, y->value.integer);
      return range_check (result, "OR");
    }
  else /* BT_LOGICAL */
    {
      result = gfc_constant_result (BT_LOGICAL, kind, &x->where);
      result->value.logical = x->value.logical || y->value.logical;
      return result;
    }
}
 
 
gfc_expr *
gfc_simplify_pack (gfc_expr *array, gfc_expr *mask, gfc_expr *vector)
{
  gfc_expr *result;
  gfc_constructor *array_ctor, *mask_ctor, *vector_ctor;
 
  if (!is_constant_array_expr(array)
      || !is_constant_array_expr(vector)
      || (!gfc_is_constant_expr (mask)
          && !is_constant_array_expr(mask)))
    return NULL;
 
  result = gfc_start_constructor (array->ts.type,
                                  array->ts.kind,
                                  &array->where);
 
  array_ctor = array->value.constructor;
  vector_ctor = vector ? vector->value.constructor : NULL;
 
  if (mask->expr_type == EXPR_CONSTANT
      && mask->value.logical)
    {
      /* Copy all elements of ARRAY to RESULT.  */
      while (array_ctor)
        {
          gfc_append_constructor (result,
                                  gfc_copy_expr (array_ctor->expr));
 
          ADVANCE (array_ctor, 1);
          ADVANCE (vector_ctor, 1);
        }
    }
  else if (mask->expr_type == EXPR_ARRAY)
    {
      /* Copy only those elements of ARRAY to RESULT whose
         MASK equals .TRUE..  */
      mask_ctor = mask->value.constructor;
      while (mask_ctor)
        {
          if (mask_ctor->expr->value.logical)
            {
              gfc_append_constructor (result,
                                      gfc_copy_expr (array_ctor->expr));
              ADVANCE (vector_ctor, 1);
            }
 
          ADVANCE (array_ctor, 1);
          ADVANCE (mask_ctor, 1);
        }
    }
 
  /* Append any left-over elements from VECTOR to RESULT.  */
  while (vector_ctor)
    {
      gfc_append_constructor (result,
                              gfc_copy_expr (vector_ctor->expr));
      ADVANCE (vector_ctor, 1);
    }
 
  result->shape = gfc_get_shape (1);
  gfc_array_size (result, &result->shape[0]);
 
  if (array->ts.type == BT_CHARACTER)
    result->ts.u.cl = array->ts.u.cl;
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_precision (gfc_expr *e)
{
  gfc_expr *result;
  int i;
 
  i = gfc_validate_kind (e->ts.type, e->ts.kind, false);
 
  result = gfc_int_expr (gfc_real_kinds[i].precision);
  result->where = e->where;
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_product (gfc_expr *array, gfc_expr *dim, gfc_expr *mask)
{
  gfc_expr *result;
 
  if (!is_constant_array_expr (array)
      || !gfc_is_constant_expr (dim))
    return NULL;
 
  if (mask
      && !is_constant_array_expr (mask)
      && mask->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = transformational_result (array, dim, array->ts.type,
                                    array->ts.kind, &array->where);
  init_result_expr (result, 1, NULL);
 
  return !dim || array->rank == 1 ?
    simplify_transformation_to_scalar (result, array, mask, gfc_multiply) :
    simplify_transformation_to_array (result, array, dim, mask, gfc_multiply);
}
 
 
gfc_expr *
gfc_simplify_radix (gfc_expr *e)
{
  gfc_expr *result;
  int i;
 
  i = gfc_validate_kind (e->ts.type, e->ts.kind, false);
  switch (e->ts.type)
    {
    case BT_INTEGER:
      i = gfc_integer_kinds[i].radix;
      break;
 
    case BT_REAL:
      i = gfc_real_kinds[i].radix;
      break;
 
    default:
      gcc_unreachable ();
    }
 
  result = gfc_int_expr (i);
  result->where = e->where;
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_range (gfc_expr *e)
{
  gfc_expr *result;
  int i;
  long j;
 
  i = gfc_validate_kind (e->ts.type, e->ts.kind, false);
 
  switch (e->ts.type)
    {
    case BT_INTEGER:
      j = gfc_integer_kinds[i].range;
      break;
 
    case BT_REAL:
    case BT_COMPLEX:
      j = gfc_real_kinds[i].range;
      break;
 
    default:
      gcc_unreachable ();
    }
 
  result = gfc_int_expr (j);
  result->where = e->where;
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_real (gfc_expr *e, gfc_expr *k)
{
  gfc_expr *result = NULL;
  int kind;
 
  if (e->ts.type == BT_COMPLEX)
    kind = get_kind (BT_REAL, k, "REAL", e->ts.kind);
  else
    kind = get_kind (BT_REAL, k, "REAL", gfc_default_real_kind);
 
  if (kind == -1)
    return &gfc_bad_expr;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  switch (e->ts.type)
    {
    case BT_INTEGER:
      if (!e->is_boz)
        result = gfc_int2real (e, kind);
      break;
 
    case BT_REAL:
      result = gfc_real2real (e, kind);
      break;
 
    case BT_COMPLEX:
      result = gfc_complex2real (e, kind);
      break;
 
    default:
      gfc_internal_error ("bad type in REAL");
      /* Not reached */
    }
 
  if (e->ts.type == BT_INTEGER && e->is_boz)
    {
      gfc_typespec ts;
      gfc_clear_ts (&ts);
      ts.type = BT_REAL;
      ts.kind = kind;
      result = gfc_copy_expr (e);
      if (!gfc_convert_boz (result, &ts))
        {
          gfc_free_expr (result);
          return &gfc_bad_expr;
        }
    }
 
  return range_check (result, "REAL");
}
 
 
gfc_expr *
gfc_simplify_realpart (gfc_expr *e)
{
  gfc_expr *result;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (BT_REAL, e->ts.kind, &e->where);
  mpc_real (result->value.real, e->value.complex, GFC_RND_MODE);
  return range_check (result, "REALPART");
}
 
gfc_expr *
gfc_simplify_repeat (gfc_expr *e, gfc_expr *n)
{
  gfc_expr *result;
  int i, j, len, ncop, nlen;
  mpz_t ncopies;
  bool have_length = false;
 
  /* If NCOPIES isn't a constant, there's nothing we can do.  */
  if (n->expr_type != EXPR_CONSTANT)
    return NULL;
 
  /* If NCOPIES is negative, it's an error.  */
  if (mpz_sgn (n->value.integer) < 0)
    {
      gfc_error ("Argument NCOPIES of REPEAT intrinsic is negative at %L",
                 &n->where);
      return &gfc_bad_expr;
    }
 
  /* If we don't know the character length, we can do no more.  */
  if (e->ts.u.cl && e->ts.u.cl->length
        && e->ts.u.cl->length->expr_type == EXPR_CONSTANT)
    {
      len = mpz_get_si (e->ts.u.cl->length->value.integer);
      have_length = true;
    }
  else if (e->expr_type == EXPR_CONSTANT
             && (e->ts.u.cl == NULL || e->ts.u.cl->length == NULL))
    {
      len = e->value.character.length;
    }
  else
    return NULL;
 
  /* If the source length is 0, any value of NCOPIES is valid
     and everything behaves as if NCOPIES == 0.  */
  mpz_init (ncopies);
  if (len == 0)
    mpz_set_ui (ncopies, 0);
  else
    mpz_set (ncopies, n->value.integer);
 
  /* Check that NCOPIES isn't too large.  */
  if (len)
    {
      mpz_t max, mlen;
      int i;
 
      /* Compute the maximum value allowed for NCOPIES: huge(cl) / len.  */
      mpz_init (max);
      i = gfc_validate_kind (BT_INTEGER, gfc_charlen_int_kind, false);
 
      if (have_length)
        {
          mpz_tdiv_q (max, gfc_integer_kinds[i].huge,
                      e->ts.u.cl->length->value.integer);
        }
      else
        {
          mpz_init_set_si (mlen, len);
          mpz_tdiv_q (max, gfc_integer_kinds[i].huge, mlen);
          mpz_clear (mlen);
        }
 
      /* The check itself.  */
      if (mpz_cmp (ncopies, max) > 0)
        {
          mpz_clear (max);
          mpz_clear (ncopies);
          gfc_error ("Argument NCOPIES of REPEAT intrinsic is too large at %L",
                     &n->where);
          return &gfc_bad_expr;
        }
 
      mpz_clear (max);
    }
  mpz_clear (ncopies);
 
  /* For further simplification, we need the character string to be
     constant.  */
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  if (len ||
      (e->ts.u.cl->length &&
       mpz_sgn (e->ts.u.cl->length->value.integer)) != 0)
    {
      const char *res = gfc_extract_int (n, &ncop);
      gcc_assert (res == NULL);
    }
  else
    ncop = 0;
 
  len = e->value.character.length;
  nlen = ncop * len;
 
  result = gfc_constant_result (BT_CHARACTER, e->ts.kind, &e->where);
 
  if (ncop == 0)
    {
      result->value.character.string = gfc_get_wide_string (1);
      result->value.character.length = 0;
      result->value.character.string[0] = '\0';
      return result;
    }
 
  result->value.character.length = nlen;
  result->value.character.string = gfc_get_wide_string (nlen + 1);
 
  for (i = 0; i < ncop; i++)
    for (j = 0; j < len; j++)
      result->value.character.string[j+i*len]= e->value.character.string[j];
 
  result->value.character.string[nlen] = '\0';  /* For debugger */
  return result;
}
 
 
/* This one is a bear, but mainly has to do with shuffling elements.  */
 
gfc_expr *
gfc_simplify_reshape (gfc_expr *source, gfc_expr *shape_exp,
                      gfc_expr *pad, gfc_expr *order_exp)
{
  int order[GFC_MAX_DIMENSIONS], shape[GFC_MAX_DIMENSIONS];
  int i, rank, npad, x[GFC_MAX_DIMENSIONS];
  gfc_constructor *head, *tail;
  mpz_t index, size;
  unsigned long j;
  size_t nsource;
  gfc_expr *e;
 
  /* Check that argument expression types are OK.  */
  if (!is_constant_array_expr (source)
      || !is_constant_array_expr (shape_exp)
      || !is_constant_array_expr (pad)
      || !is_constant_array_expr (order_exp))
    return NULL;
 
  /* Proceed with simplification, unpacking the array.  */
 
  mpz_init (index);
  rank = 0;
  head = tail = NULL;
 
  for (;;)
    {
      e = gfc_get_array_element (shape_exp, rank);
      if (e == NULL)
        break;
 
      gfc_extract_int (e, &shape[rank]);
 
      gcc_assert (rank >= 0 && rank < GFC_MAX_DIMENSIONS);
      gcc_assert (shape[rank] >= 0);
 
      gfc_free_expr (e);
      rank++;
    }
 
  gcc_assert (rank > 0);
 
  /* Now unpack the order array if present.  */
  if (order_exp == NULL)
    {
      for (i = 0; i < rank; i++)
        order[i] = i;
    }
  else
    {
      for (i = 0; i < rank; i++)
        x[i] = 0;
 
      for (i = 0; i < rank; i++)
        {
          e = gfc_get_array_element (order_exp, i);
          gcc_assert (e);
 
          gfc_extract_int (e, &order[i]);
          gfc_free_expr (e);
 
          gcc_assert (order[i] >= 1 && order[i] <= rank);
          order[i]--;
          gcc_assert (x[order[i]] == 0);
          x[order[i]] = 1;
        }
    }
 
  /* Count the elements in the source and padding arrays.  */
 
  npad = 0;
  if (pad != NULL)
    {
      gfc_array_size (pad, &size);
      npad = mpz_get_ui (size);
      mpz_clear (size);
    }
 
  gfc_array_size (source, &size);
  nsource = mpz_get_ui (size);
  mpz_clear (size);
 
  /* If it weren't for that pesky permutation we could just loop
     through the source and round out any shortage with pad elements.
     But no, someone just had to have the compiler do something the
     user should be doing.  */
 
  for (i = 0; i < rank; i++)
    x[i] = 0;
 
  while (nsource > 0 || npad > 0)
    {
      /* Figure out which element to extract.  */
      mpz_set_ui (index, 0);
 
      for (i = rank - 1; i >= 0; i--)
        {
          mpz_add_ui (index, index, x[order[i]]);
          if (i != 0)
            mpz_mul_ui (index, index, shape[order[i - 1]]);
        }
 
      if (mpz_cmp_ui (index, INT_MAX) > 0)
        gfc_internal_error ("Reshaped array too large at %C");
 
      j = mpz_get_ui (index);
 
      if (j < nsource)
        e = gfc_get_array_element (source, j);
      else
        {
          gcc_assert (npad > 0);
 
          j = j - nsource;
          j = j % npad;
          e = gfc_get_array_element (pad, j);
        }
      gcc_assert (e);
 
      if (head == NULL)
        head = tail = gfc_get_constructor ();
      else
        {
          tail->next = gfc_get_constructor ();
          tail = tail->next;
        }
 
      tail->where = e->where;
      tail->expr = e;
 
      /* Calculate the next element.  */
      i = 0;
 
inc:
      if (++x[i] < shape[i])
        continue;
      x[i++] = 0;
      if (i < rank)
        goto inc;
 
      break;
    }
 
  mpz_clear (index);
 
  e = gfc_get_expr ();
  e->where = source->where;
  e->expr_type = EXPR_ARRAY;
  e->value.constructor = head;
  e->shape = gfc_get_shape (rank);
 
  for (i = 0; i < rank; i++)
    mpz_init_set_ui (e->shape[i], shape[i]);
 
  e->ts = source->ts;
  e->rank = rank;
 
  return e;
}
 
 
gfc_expr *
gfc_simplify_rrspacing (gfc_expr *x)
{
  gfc_expr *result;
  int i;
  long int e, p;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  i = gfc_validate_kind (x->ts.type, x->ts.kind, false);
 
  result = gfc_constant_result (BT_REAL, x->ts.kind, &x->where);
 
  mpfr_abs (result->value.real, x->value.real, GFC_RND_MODE);
 
  /* Special case x = -0 and 0.  */
  if (mpfr_sgn (result->value.real) == 0)
    {
      mpfr_set_ui (result->value.real, 0, GFC_RND_MODE);
      return result;
    }
 
  /* | x * 2**(-e) | * 2**p.  */
  e = - (long int) mpfr_get_exp (x->value.real);
  mpfr_mul_2si (result->value.real, result->value.real, e, GFC_RND_MODE);
 
  p = (long int) gfc_real_kinds[i].digits;
  mpfr_mul_2si (result->value.real, result->value.real, p, GFC_RND_MODE);
 
  return range_check (result, "RRSPACING");
}
 
 
gfc_expr *
gfc_simplify_scale (gfc_expr *x, gfc_expr *i)
{
  int k, neg_flag, power, exp_range;
  mpfr_t scale, radix;
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT || i->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (BT_REAL, x->ts.kind, &x->where);
 
  if (mpfr_sgn (x->value.real) == 0)
    {
      mpfr_set_ui (result->value.real, 0, GFC_RND_MODE);
      return result;
    }
 
  k = gfc_validate_kind (BT_REAL, x->ts.kind, false);
 
  exp_range = gfc_real_kinds[k].max_exponent - gfc_real_kinds[k].min_exponent;
 
  /* This check filters out values of i that would overflow an int.  */
  if (mpz_cmp_si (i->value.integer, exp_range + 2) > 0
      || mpz_cmp_si (i->value.integer, -exp_range - 2) < 0)
    {
      gfc_error ("Result of SCALE overflows its kind at %L", &result->where);
      gfc_free_expr (result);
      return &gfc_bad_expr;
    }
 
  /* Compute scale = radix ** power.  */
  power = mpz_get_si (i->value.integer);
 
  if (power >= 0)
    neg_flag = 0;
  else
    {
      neg_flag = 1;
      power = -power;
    }
 
  gfc_set_model_kind (x->ts.kind);
  mpfr_init (scale);
  mpfr_init (radix);
  mpfr_set_ui (radix, gfc_real_kinds[k].radix, GFC_RND_MODE);
  mpfr_pow_ui (scale, radix, power, GFC_RND_MODE);
 
  if (neg_flag)
    mpfr_div (result->value.real, x->value.real, scale, GFC_RND_MODE);
  else
    mpfr_mul (result->value.real, x->value.real, scale, GFC_RND_MODE);
 
  mpfr_clears (scale, radix, NULL);
 
  return range_check (result, "SCALE");
}
 
 
/* Variants of strspn and strcspn that operate on wide characters.  */
 
static size_t
wide_strspn (const gfc_char_t *s1, const gfc_char_t *s2)
{
  size_t i = 0;
  const gfc_char_t *c;
 
  while (s1[i])
    {
      for (c = s2; *c; c++)
        {
          if (s1[i] == *c)
            break;
        }
      if (*c == '\0')
        break;
      i++;
    }
 
  return i;
}
 
static size_t
wide_strcspn (const gfc_char_t *s1, const gfc_char_t *s2)
{
  size_t i = 0;
  const gfc_char_t *c;
 
  while (s1[i])
    {
      for (c = s2; *c; c++)
        {
          if (s1[i] == *c)
            break;
        }
      if (*c)
        break;
      i++;
    }
 
  return i;
}
 
 
gfc_expr *
gfc_simplify_scan (gfc_expr *e, gfc_expr *c, gfc_expr *b, gfc_expr *kind)
{
  gfc_expr *result;
  int back;
  size_t i;
  size_t indx, len, lenc;
  int k = get_kind (BT_INTEGER, kind, "SCAN", gfc_default_integer_kind);
 
  if (k == -1)
    return &gfc_bad_expr;
 
  if (e->expr_type != EXPR_CONSTANT || c->expr_type != EXPR_CONSTANT)
    return NULL;
 
  if (b != NULL && b->value.logical != 0)
    back = 1;
  else
    back = 0;
 
  result = gfc_constant_result (BT_INTEGER, k, &e->where);
 
  len = e->value.character.length;
  lenc = c->value.character.length;
 
  if (len == 0 || lenc == 0)
    {
      indx = 0;
    }
  else
    {
      if (back == 0)
        {
          indx = wide_strcspn (e->value.character.string,
                               c->value.character.string) + 1;
          if (indx > len)
            indx = 0;
        }
      else
        {
          i = 0;
          for (indx = len; indx > 0; indx--)
            {
              for (i = 0; i < lenc; i++)
                {
                  if (c->value.character.string[i]
                      == e->value.character.string[indx - 1])
                    break;
                }
              if (i < lenc)
                break;
            }
        }
    }
  mpz_set_ui (result->value.integer, indx);
  return range_check (result, "SCAN");
}
 
 
gfc_expr *
gfc_simplify_selected_char_kind (gfc_expr *e)
{
  int kind;
  gfc_expr *result;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  if (gfc_compare_with_Cstring (e, "ascii", false) == 0
      || gfc_compare_with_Cstring (e, "default", false) == 0)
    kind = 1;
  else if (gfc_compare_with_Cstring (e, "iso_10646", false) == 0)
    kind = 4;
  else
    kind = -1;
 
  result = gfc_int_expr (kind);
  result->where = e->where;
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_selected_int_kind (gfc_expr *e)
{
  int i, kind, range;
  gfc_expr *result;
 
  if (e->expr_type != EXPR_CONSTANT || gfc_extract_int (e, &range) != NULL)
    return NULL;
 
  kind = INT_MAX;
 
  for (i = 0; gfc_integer_kinds[i].kind != 0; i++)
    if (gfc_integer_kinds[i].range >= range
        && gfc_integer_kinds[i].kind < kind)
      kind = gfc_integer_kinds[i].kind;
 
  if (kind == INT_MAX)
    kind = -1;
 
  result = gfc_int_expr (kind);
  result->where = e->where;
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_selected_real_kind (gfc_expr *p, gfc_expr *q)
{
  int range, precision, i, kind, found_precision, found_range;
  gfc_expr *result;
 
  if (p == NULL)
    precision = 0;
  else
    {
      if (p->expr_type != EXPR_CONSTANT
          || gfc_extract_int (p, &precision) != NULL)
        return NULL;
    }
 
  if (q == NULL)
    range = 0;
  else
    {
      if (q->expr_type != EXPR_CONSTANT
          || gfc_extract_int (q, &range) != NULL)
        return NULL;
    }
 
  kind = INT_MAX;
  found_precision = 0;
  found_range = 0;
 
  for (i = 0; gfc_real_kinds[i].kind != 0; i++)
    {
      if (gfc_real_kinds[i].precision >= precision)
        found_precision = 1;
 
      if (gfc_real_kinds[i].range >= range)
        found_range = 1;
 
      if (gfc_real_kinds[i].precision >= precision
          && gfc_real_kinds[i].range >= range && gfc_real_kinds[i].kind < kind)
        kind = gfc_real_kinds[i].kind;
    }
 
  if (kind == INT_MAX)
    {
      kind = 0;
 
      if (!found_precision)
        kind = -1;
      if (!found_range)
        kind -= 2;
    }
 
  result = gfc_int_expr (kind);
  result->where = (p != NULL) ? p->where : q->where;
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_set_exponent (gfc_expr *x, gfc_expr *i)
{
  gfc_expr *result;
  mpfr_t exp, absv, log2, pow2, frac;
  unsigned long exp2;
 
  if (x->expr_type != EXPR_CONSTANT || i->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (BT_REAL, x->ts.kind, &x->where);
 
  if (mpfr_sgn (x->value.real) == 0)
    {
      mpfr_set_ui (result->value.real, 0, GFC_RND_MODE);
      return result;
    }
 
  gfc_set_model_kind (x->ts.kind);
  mpfr_init (absv);
  mpfr_init (log2);
  mpfr_init (exp);
  mpfr_init (pow2);
  mpfr_init (frac);
 
  mpfr_abs (absv, x->value.real, GFC_RND_MODE);
  mpfr_log2 (log2, absv, GFC_RND_MODE);
 
  mpfr_trunc (log2, log2);
  mpfr_add_ui (exp, log2, 1, GFC_RND_MODE);
 
  /* Old exponent value, and fraction.  */
  mpfr_ui_pow (pow2, 2, exp, GFC_RND_MODE);
 
  mpfr_div (frac, absv, pow2, GFC_RND_MODE);
 
  /* New exponent.  */
  exp2 = (unsigned long) mpz_get_d (i->value.integer);
  mpfr_mul_2exp (result->value.real, frac, exp2, GFC_RND_MODE);
 
  mpfr_clears (absv, log2, pow2, frac, NULL);
 
  return range_check (result, "SET_EXPONENT");
}
 
 
gfc_expr *
gfc_simplify_shape (gfc_expr *source)
{
  mpz_t shape[GFC_MAX_DIMENSIONS];
  gfc_expr *result, *e, *f;
  gfc_array_ref *ar;
  int n;
  gfc_try t;
 
  if (source->rank == 0)
    return gfc_start_constructor (BT_INTEGER, gfc_default_integer_kind,
                                  &source->where);
 
  if (source->expr_type != EXPR_VARIABLE)
    return NULL;
 
  result = gfc_start_constructor (BT_INTEGER, gfc_default_integer_kind,
                                  &source->where);
 
  ar = gfc_find_array_ref (source);
 
  t = gfc_array_ref_shape (ar, shape);
 
  for (n = 0; n < source->rank; n++)
    {
      e = gfc_constant_result (BT_INTEGER, gfc_default_integer_kind,
                               &source->where);
 
      if (t == SUCCESS)
        {
          mpz_set (e->value.integer, shape[n]);
          mpz_clear (shape[n]);
        }
      else
        {
          mpz_set_ui (e->value.integer, n + 1);
 
          f = gfc_simplify_size (source, e, NULL);
          gfc_free_expr (e);
          if (f == NULL)
            {
              gfc_free_expr (result);
              return NULL;
            }
          else
            {
              e = f;
            }
        }
 
      gfc_append_constructor (result, e);
    }
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_size (gfc_expr *array, gfc_expr *dim, gfc_expr *kind)
{
  mpz_t size;
  gfc_expr *result;
  int d;
  int k = get_kind (BT_INTEGER, kind, "SIZE", gfc_default_integer_kind);
 
  if (k == -1)
    return &gfc_bad_expr;
 
  if (dim == NULL)
    {
      if (gfc_array_size (array, &size) == FAILURE)
        return NULL;
    }
  else
    {
      if (dim->expr_type != EXPR_CONSTANT)
        return NULL;
 
      d = mpz_get_ui (dim->value.integer) - 1;
      if (gfc_array_dimen_size (array, d, &size) == FAILURE)
        return NULL;
    }
 
  result = gfc_constant_result (BT_INTEGER, k, &array->where);
  mpz_set (result->value.integer, size);
  return result;
}
 
 
gfc_expr *
gfc_simplify_sign (gfc_expr *x, gfc_expr *y)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT || y->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
 
  switch (x->ts.type)
    {
    case BT_INTEGER:
      mpz_abs (result->value.integer, x->value.integer);
      if (mpz_sgn (y->value.integer) < 0)
        mpz_neg (result->value.integer, result->value.integer);
      break;
 
    case BT_REAL:
      if (gfc_option.flag_sign_zero)
        mpfr_copysign (result->value.real, x->value.real, y->value.real,
                       GFC_RND_MODE);
      else
        mpfr_setsign (result->value.real, x->value.real,
                      mpfr_sgn (y->value.real) < 0 ? 1 : 0, GFC_RND_MODE);
      break;
 
    default:
      gfc_internal_error ("Bad type in gfc_simplify_sign");
    }
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_sin (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
 
  switch (x->ts.type)
    {
    case BT_REAL:
      mpfr_sin (result->value.real, x->value.real, GFC_RND_MODE);
      break;
 
    case BT_COMPLEX:
      gfc_set_model (x->value.real);
      mpc_sin (result->value.complex, x->value.complex, GFC_MPC_RND_MODE);
      break;
 
    default:
      gfc_internal_error ("in gfc_simplify_sin(): Bad type");
    }
 
  return range_check (result, "SIN");
}
 
 
gfc_expr *
gfc_simplify_sinh (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
 
  if (x->ts.type == BT_REAL)
    mpfr_sinh (result->value.real, x->value.real, GFC_RND_MODE);
  else if (x->ts.type == BT_COMPLEX)
    mpc_sinh (result->value.complex, x->value.complex, GFC_MPC_RND_MODE);
  else
    gcc_unreachable ();
 
 
  return range_check (result, "SINH");
}
 
 
/* The argument is always a double precision real that is converted to
   single precision.  TODO: Rounding!  */
 
gfc_expr *
gfc_simplify_sngl (gfc_expr *a)
{
  gfc_expr *result;
 
  if (a->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_real2real (a, gfc_default_real_kind);
  return range_check (result, "SNGL");
}
 
 
gfc_expr *
gfc_simplify_spacing (gfc_expr *x)
{
  gfc_expr *result;
  int i;
  long int en, ep;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  i = gfc_validate_kind (x->ts.type, x->ts.kind, false);
 
  result = gfc_constant_result (BT_REAL, x->ts.kind, &x->where);
 
  /* Special case x = 0 and -0.  */
  mpfr_abs (result->value.real, x->value.real, GFC_RND_MODE);
  if (mpfr_sgn (result->value.real) == 0)
    {
      mpfr_set (result->value.real, gfc_real_kinds[i].tiny, GFC_RND_MODE);
      return result;
    }
 
  /* In the Fortran 95 standard, the result is b**(e - p) where b, e, and p
     are the radix, exponent of x, and precision.  This excludes the
     possibility of subnormal numbers.  Fortran 2003 states the result is
     b**max(e - p, emin - 1).  */
 
  ep = (long int) mpfr_get_exp (x->value.real) - gfc_real_kinds[i].digits;
  en = (long int) gfc_real_kinds[i].min_exponent - 1;
  en = en > ep ? en : ep;
 
  mpfr_set_ui (result->value.real, 1, GFC_RND_MODE);
  mpfr_mul_2si (result->value.real, result->value.real, en, GFC_RND_MODE);
 
  return range_check (result, "SPACING");
}
 
 
gfc_expr *
gfc_simplify_spread (gfc_expr *source, gfc_expr *dim_expr, gfc_expr *ncopies_expr)
{
  gfc_expr *result = 0L;
  int i, j, dim, ncopies;
  mpz_t size;
 
  if ((!gfc_is_constant_expr (source)
       && !is_constant_array_expr (source))
      || !gfc_is_constant_expr (dim_expr)
      || !gfc_is_constant_expr (ncopies_expr))
    return NULL;
 
  gcc_assert (dim_expr->ts.type == BT_INTEGER);
  gfc_extract_int (dim_expr, &dim);
  dim -= 1;   /* zero-base DIM */
 
  gcc_assert (ncopies_expr->ts.type == BT_INTEGER);
  gfc_extract_int (ncopies_expr, &ncopies);
  ncopies = MAX (ncopies, 0);
 
  /* Do not allow the array size to exceed the limit for an array
     constructor.  */
  if (source->expr_type == EXPR_ARRAY)
    {
      if (gfc_array_size (source, &size) == FAILURE)
        gfc_internal_error ("Failure getting length of a constant array.");
    }
  else
    mpz_init_set_ui (size, 1);
 
  if (mpz_get_si (size)*ncopies > gfc_option.flag_max_array_constructor)
    return NULL;
 
  if (source->expr_type == EXPR_CONSTANT)
    {
      gcc_assert (dim == 0);
 
      result = gfc_start_constructor (source->ts.type,
                                      source->ts.kind,
                                      &source->where);
      result->rank = 1;
      result->shape = gfc_get_shape (result->rank);
      mpz_init_set_si (result->shape[0], ncopies);
 
      for (i = 0; i < ncopies; ++i)
        gfc_append_constructor (result, gfc_copy_expr (source));
    }
  else if (source->expr_type == EXPR_ARRAY)
    {
      int result_size, rstride[GFC_MAX_DIMENSIONS], extent[GFC_MAX_DIMENSIONS];
      gfc_constructor *ctor, *source_ctor, *result_ctor;
 
      gcc_assert (source->rank < GFC_MAX_DIMENSIONS);
      gcc_assert (dim >= 0 && dim <= source->rank);
 
      result = gfc_start_constructor (source->ts.type,
                                      source->ts.kind,
                                      &source->where);
      result->rank = source->rank + 1;
      result->shape = gfc_get_shape (result->rank);
 
      result_size = 1;
      for (i = 0, j = 0; i < result->rank; ++i)
        {
          if (i != dim)
            mpz_init_set (result->shape[i], source->shape[j++]);
          else
            mpz_init_set_si (result->shape[i], ncopies);
 
          extent[i] = mpz_get_si (result->shape[i]);
          rstride[i] = (i == 0) ? 1 : rstride[i-1] * extent[i-1];
          result_size *= extent[i];
        }
 
      for (i = 0; i < result_size; ++i)
        gfc_append_constructor (result, NULL);
 
      source_ctor = source->value.constructor;
      result_ctor = result->value.constructor;
      while (source_ctor)
        {
          ctor = result_ctor;
 
          for (i = 0; i < ncopies; ++i)
          {
            ctor->expr = gfc_copy_expr (source_ctor->expr);
            ADVANCE (ctor, rstride[dim]);
          }
 
          ADVANCE (result_ctor, (dim == 0 ? ncopies : 1));
          ADVANCE (source_ctor, 1);
        }
    }
  else
    /* FIXME: Returning here avoids a regression in array_simplify_1.f90.
       Replace NULL with gcc_unreachable() after implementing
       gfc_simplify_cshift(). */
    return NULL;
 
  if (source->ts.type == BT_CHARACTER)
    result->ts.u.cl = source->ts.u.cl;
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_sqrt (gfc_expr *e)
{
  gfc_expr *result;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (e->ts.type, e->ts.kind, &e->where);
 
  switch (e->ts.type)
    {
    case BT_REAL:
      if (mpfr_cmp_si (e->value.real, 0) < 0)
        goto negative_arg;
      mpfr_sqrt (result->value.real, e->value.real, GFC_RND_MODE);
 
      break;
 
    case BT_COMPLEX:
      gfc_set_model (e->value.real);
      mpc_sqrt (result->value.complex, e->value.complex, GFC_MPC_RND_MODE);
      break;
 
    default:
      gfc_internal_error ("invalid argument of SQRT at %L", &e->where);
    }
 
  return range_check (result, "SQRT");
 
negative_arg:
  gfc_free_expr (result);
  gfc_error ("Argument of SQRT at %L has a negative value", &e->where);
  return &gfc_bad_expr;
}
 
 
gfc_expr *
gfc_simplify_sum (gfc_expr *array, gfc_expr *dim, gfc_expr *mask)
{
  gfc_expr *result;
 
  if (!is_constant_array_expr (array)
      || !gfc_is_constant_expr (dim))
    return NULL;
 
  if (mask
      && !is_constant_array_expr (mask)
      && mask->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = transformational_result (array, dim, array->ts.type,
                                    array->ts.kind, &array->where);
  init_result_expr (result, 0, NULL);
 
  return !dim || array->rank == 1 ?
    simplify_transformation_to_scalar (result, array, mask, gfc_add) :
    simplify_transformation_to_array (result, array, dim, mask, gfc_add);
}
 
 
gfc_expr *
gfc_simplify_tan (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
 
  if (x->ts.type == BT_REAL)
    mpfr_tan (result->value.real, x->value.real, GFC_RND_MODE);
  else if (x->ts.type == BT_COMPLEX)
    mpc_tan (result->value.complex, x->value.complex, GFC_MPC_RND_MODE);
  else
    gcc_unreachable ();
 
  return range_check (result, "TAN");
}
 
 
gfc_expr *
gfc_simplify_tanh (gfc_expr *x)
{
  gfc_expr *result;
 
  if (x->expr_type != EXPR_CONSTANT)
    return NULL;
 
  result = gfc_constant_result (x->ts.type, x->ts.kind, &x->where);
 
  if (x->ts.type == BT_REAL)
    mpfr_tanh (result->value.real, x->value.real, GFC_RND_MODE);
  else if (x->ts.type == BT_COMPLEX)
    mpc_tanh (result->value.complex, x->value.complex, GFC_MPC_RND_MODE);
  else
    gcc_unreachable ();
 
  return range_check (result, "TANH");
 
}
 
 
gfc_expr *
gfc_simplify_tiny (gfc_expr *e)
{
  gfc_expr *result;
  int i;
 
  i = gfc_validate_kind (BT_REAL, e->ts.kind, false);
 
  result = gfc_constant_result (BT_REAL, e->ts.kind, &e->where);
  mpfr_set (result->value.real, gfc_real_kinds[i].tiny, GFC_RND_MODE);
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_trailz (gfc_expr *e)
{
  gfc_expr *result;
  unsigned long tz, bs;
  int i;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  i = gfc_validate_kind (e->ts.type, e->ts.kind, false);
  bs = gfc_integer_kinds[i].bit_size;
  tz = mpz_scan1 (e->value.integer, 0);
 
  result = gfc_constant_result (BT_INTEGER, gfc_default_integer_kind, &e->where);
  mpz_set_ui (result->value.integer, MIN (tz, bs));
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_transfer (gfc_expr *source, gfc_expr *mold, gfc_expr *size)
{
  gfc_expr *result;
  gfc_expr *mold_element;
  size_t source_size;
  size_t result_size;
  size_t result_elt_size;
  size_t buffer_size;
  mpz_t tmp;
  unsigned char *buffer;
 
  if (!gfc_is_constant_expr (source)
        || (gfc_init_expr && !gfc_is_constant_expr (mold))
        || !gfc_is_constant_expr (size))
    return NULL;
 
  if (source->expr_type == EXPR_FUNCTION)
    return NULL;
 
  /* Calculate the size of the source.  */
  if (source->expr_type == EXPR_ARRAY
      && gfc_array_size (source, &tmp) == FAILURE)
    gfc_internal_error ("Failure getting length of a constant array.");
 
  source_size = gfc_target_expr_size (source);
 
  /* Create an empty new expression with the appropriate characteristics.  */
  result = gfc_constant_result (mold->ts.type, mold->ts.kind,
                                &source->where);
  result->ts = mold->ts;
 
  mold_element = mold->expr_type == EXPR_ARRAY
                 ? mold->value.constructor->expr
                 : mold;
 
  /* Set result character length, if needed.  Note that this needs to be
     set even for array expressions, in order to pass this information into
     gfc_target_interpret_expr.  */
  if (result->ts.type == BT_CHARACTER && gfc_is_constant_expr (mold_element))
    result->value.character.length = mold_element->value.character.length;
 
  /* Set the number of elements in the result, and determine its size.  */
  result_elt_size = gfc_target_expr_size (mold_element);
  if (result_elt_size == 0)
    {
      gfc_free_expr (result);
      return NULL;
    }
 
  if (mold->expr_type == EXPR_ARRAY || mold->rank || size)
    {
      int result_length;
 
      result->expr_type = EXPR_ARRAY;
      result->rank = 1;
 
      if (size)
        result_length = (size_t)mpz_get_ui (size->value.integer);
      else
        {
          result_length = source_size / result_elt_size;
          if (result_length * result_elt_size < source_size)
            result_length += 1;
        }
 
      result->shape = gfc_get_shape (1);
      mpz_init_set_ui (result->shape[0], result_length);
 
      result_size = result_length * result_elt_size;
    }
  else
    {
      result->rank = 0;
      result_size = result_elt_size;
    }
 
  if (gfc_option.warn_surprising && source_size < result_size)
    gfc_warning("Intrinsic TRANSFER at %L has partly undefined result: "
                "source size %ld < result size %ld", &source->where,
                (long) source_size, (long) result_size);
 
  /* Allocate the buffer to store the binary version of the source.  */
  buffer_size = MAX (source_size, result_size);
  buffer = (unsigned char*)alloca (buffer_size);
  memset (buffer, 0, buffer_size);
 
  /* Now write source to the buffer.  */
  gfc_target_encode_expr (source, buffer, buffer_size);
 
  /* And read the buffer back into the new expression.  */
  gfc_target_interpret_expr (buffer, buffer_size, result);
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_transpose (gfc_expr *matrix)
{
  int i, matrix_rows;
  gfc_expr *result;
  gfc_constructor *matrix_ctor;
 
  if (!is_constant_array_expr (matrix))
    return NULL;
 
  gcc_assert (matrix->rank == 2);
 
  result = gfc_start_constructor (matrix->ts.type, matrix->ts.kind, &matrix->where);
  result->rank = 2;
  result->shape = gfc_get_shape (result->rank);
  mpz_set (result->shape[0], matrix->shape[1]);
  mpz_set (result->shape[1], matrix->shape[0]);
 
  if (matrix->ts.type == BT_CHARACTER)
    result->ts.u.cl = matrix->ts.u.cl;
 
  matrix_rows = mpz_get_si (matrix->shape[0]);
  matrix_ctor = matrix->value.constructor;
  for (i = 0; i < matrix_rows; ++i)
    {
      gfc_constructor *column_ctor = matrix_ctor;
      while (column_ctor)
        {
          gfc_append_constructor (result,
                                  gfc_copy_expr (column_ctor->expr));
 
          ADVANCE (column_ctor, matrix_rows);
        }
 
      ADVANCE (matrix_ctor, 1);
    }
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_trim (gfc_expr *e)
{
  gfc_expr *result;
  int count, i, len, lentrim;
 
  if (e->expr_type != EXPR_CONSTANT)
    return NULL;
 
  len = e->value.character.length;
 
  result = gfc_constant_result (BT_CHARACTER, e->ts.kind, &e->where);
 
  for (count = 0, i = 1; i <= len; ++i)
    {
      if (e->value.character.string[len - i] == ' ')
        count++;
      else
        break;
    }
 
  lentrim = len - count;
 
  result->value.character.length = lentrim;
  result->value.character.string = gfc_get_wide_string (lentrim + 1);
 
  for (i = 0; i < lentrim; i++)
    result->value.character.string[i] = e->value.character.string[i];
 
  result->value.character.string[lentrim] = '\0';       /* For debugger */
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_ubound (gfc_expr *array, gfc_expr *dim, gfc_expr *kind)
{
  return simplify_bound (array, dim, kind, 1);
}
 
 
gfc_expr *
gfc_simplify_unpack (gfc_expr *vector, gfc_expr *mask, gfc_expr *field)
{
  gfc_expr *result, *e;
  gfc_constructor *vector_ctor, *mask_ctor, *field_ctor;
 
  if (!is_constant_array_expr (vector)
      || !is_constant_array_expr (mask)
      || (!gfc_is_constant_expr (field)
          && !is_constant_array_expr(field)))
    return NULL;
 
  result = gfc_start_constructor (vector->ts.type,
                                  vector->ts.kind,
                                  &vector->where);
  result->rank = mask->rank;
  result->shape = gfc_copy_shape (mask->shape, mask->rank);
 
  if (vector->ts.type == BT_CHARACTER)
    result->ts.u.cl = vector->ts.u.cl;
 
  vector_ctor = vector->value.constructor;
  mask_ctor = mask->value.constructor;
  field_ctor = field->expr_type == EXPR_ARRAY ? field->value.constructor : NULL;
 
  while (mask_ctor)
    {
      if (mask_ctor->expr->value.logical)
        {
          gcc_assert (vector_ctor);
          e = gfc_copy_expr (vector_ctor->expr);
          ADVANCE (vector_ctor, 1);
        }
      else if (field->expr_type == EXPR_ARRAY)
        e = gfc_copy_expr (field_ctor->expr);
      else
        e = gfc_copy_expr (field);
 
      gfc_append_constructor (result, e);
 
      ADVANCE (mask_ctor, 1);
      ADVANCE (field_ctor, 1);
    }
 
  return result;
}
 
 
gfc_expr *
gfc_simplify_verify (gfc_expr *s, gfc_expr *set, gfc_expr *b, gfc_expr *kind)
{
  gfc_expr *result;
  int back;
  size_t index, len, lenset;
  size_t i;
  int k = get_kind (BT_INTEGER, kind, "VERIFY", gfc_default_integer_kind);
 
  if (k == -1)
    return &gfc_bad_expr;
 
  if (s->expr_type != EXPR_CONSTANT || set->expr_type != EXPR_CONSTANT)
    return NULL;
 
  if (b != NULL && b->value.logical != 0)
    back = 1;
  else
    back = 0;
 
  result = gfc_constant_result (BT_INTEGER, k, &s->where);
 
  len = s->value.character.length;
  lenset = set->value.character.length;
 
  if (len == 0)
    {
      mpz_set_ui (result->value.integer, 0);
      return result;
    }
 
  if (back == 0)
    {
      if (lenset == 0)
        {
          mpz_set_ui (result->value.integer, 1);
          return result;
        }
 
      index = wide_strspn (s->value.character.string,
                           set->value.character.string) + 1;
      if (index > len)
        index = 0;
 
    }
  else
    {
      if (lenset == 0)
        {
          mpz_set_ui (result->value.integer, len);
          return result;
        }
      for (index = len; index > 0; index --)
        {
          for (i = 0; i < lenset; i++)
            {
              if (s->value.character.string[index - 1]
                  == set->value.character.string[i])
                break;
            }
          if (i == lenset)
            break;
        }
    }
 
  mpz_set_ui (result->value.integer, index);
  return result;
}
 
 
gfc_expr *
gfc_simplify_xor (gfc_expr *x, gfc_expr *y)
{
  gfc_expr *result;
  int kind;
 
  if (x->expr_type != EXPR_CONSTANT || y->expr_type != EXPR_CONSTANT)
    return NULL;
 
  kind = x->ts.kind > y->ts.kind ? x->ts.kind : y->ts.kind;
  if (x->ts.type == BT_INTEGER)
    {
      result = gfc_constant_result (BT_INTEGER, kind, &x->where);
      mpz_xor (result->value.integer, x->value.integer, y->value.integer);
      return range_check (result, "XOR");
    }
  else /* BT_LOGICAL */
    {
      result = gfc_constant_result (BT_LOGICAL, kind, &x->where);
      result->value.logical = (x->value.logical && !y->value.logical)
                              || (!x->value.logical && y->value.logical);
      return result;
    }
 
}
 
 
/****************** Constant simplification *****************/
 
/* Master function to convert one constant to another.  While this is
   used as a simplification function, it requires the destination type
   and kind information which is supplied by a special case in
   do_simplify().  */
 
gfc_expr *
gfc_convert_constant (gfc_expr *e, bt type, int kind)
{
  gfc_expr *g, *result, *(*f) (gfc_expr *, int);
  gfc_constructor *head, *c, *tail = NULL;
 
  switch (e->ts.type)
    {
    case BT_INTEGER:
      switch (type)
        {
        case BT_INTEGER:
          f = gfc_int2int;
          break;
        case BT_REAL:
          f = gfc_int2real;
          break;
        case BT_COMPLEX:
          f = gfc_int2complex;
          break;
        case BT_LOGICAL:
          f = gfc_int2log;
          break;
        default:
          goto oops;
        }
      break;
 
    case BT_REAL:
      switch (type)
        {
        case BT_INTEGER:
          f = gfc_real2int;
          break;
        case BT_REAL:
          f = gfc_real2real;
          break;
        case BT_COMPLEX:
          f = gfc_real2complex;
          break;
        default:
          goto oops;
        }
      break;
 
    case BT_COMPLEX:
      switch (type)
        {
        case BT_INTEGER:
          f = gfc_complex2int;
          break;
        case BT_REAL:
          f = gfc_complex2real;
          break;
        case BT_COMPLEX:
          f = gfc_complex2complex;
          break;
 
        default:
          goto oops;
        }
      break;
 
    case BT_LOGICAL:
      switch (type)
        {
        case BT_INTEGER:
          f = gfc_log2int;
          break;
        case BT_LOGICAL:
          f = gfc_log2log;
          break;
        default:
          goto oops;
        }
      break;
 
    case BT_HOLLERITH:
      switch (type)
        {
        case BT_INTEGER:
          f = gfc_hollerith2int;
          break;
 
        case BT_REAL:
          f = gfc_hollerith2real;
          break;
 
        case BT_COMPLEX:
          f = gfc_hollerith2complex;
          break;
 
        case BT_CHARACTER:
          f = gfc_hollerith2character;
          break;
 
        case BT_LOGICAL:
          f = gfc_hollerith2logical;
          break;
 
        default:
          goto oops;
        }
      break;
 
    default:
    oops:
      gfc_internal_error ("gfc_convert_constant(): Unexpected type");
    }
 
  result = NULL;
 
  switch (e->expr_type)
    {
    case EXPR_CONSTANT:
      result = f (e, kind);
      if (result == NULL)
        return &gfc_bad_expr;
      break;
 
    case EXPR_ARRAY:
      if (!gfc_is_constant_expr (e))
        break;
 
      head = NULL;
 
      for (c = e->value.constructor; c; c = c->next)
        {
          if (head == NULL)
            head = tail = gfc_get_constructor ();
          else
            {
              tail->next = gfc_get_constructor ();
              tail = tail->next;
            }
 
          tail->where = c->where;
 
          if (c->iterator == NULL)
            tail->expr = f (c->expr, kind);
          else
            {
              g = gfc_convert_constant (c->expr, type, kind);
              if (g == &gfc_bad_expr)
                return g;
              tail->expr = g;
            }
 
          if (tail->expr == NULL)
            {
              gfc_free_constructor (head);
              return NULL;
            }
        }
 
      result = gfc_get_expr ();
      result->ts.type = type;
      result->ts.kind = kind;
      result->expr_type = EXPR_ARRAY;
      result->value.constructor = head;
      result->shape = gfc_copy_shape (e->shape, e->rank);
      result->where = e->where;
      result->rank = e->rank;
      break;
 
    default:
      break;
    }
 
  return result;
}
 
 
/* Function for converting character constants.  */
gfc_expr *
gfc_convert_char_constant (gfc_expr *e, bt type ATTRIBUTE_UNUSED, int kind)
{
  gfc_expr *result;
  int i;
 
  if (!gfc_is_constant_expr (e))
    return NULL;
 
  if (e->expr_type == EXPR_CONSTANT)
    {
      /* Simple case of a scalar.  */
      result = gfc_constant_result (BT_CHARACTER, kind, &e->where);
      if (result == NULL)
        return &gfc_bad_expr;
 
      result->value.character.length = e->value.character.length;
      result->value.character.string
        = gfc_get_wide_string (e->value.character.length + 1);
      memcpy (result->value.character.string, e->value.character.string,
              (e->value.character.length + 1) * sizeof (gfc_char_t));
 
      /* Check we only have values representable in the destination kind.  */
      for (i = 0; i < result->value.character.length; i++)
        if (!gfc_check_character_range (result->value.character.string[i],
                                        kind))
          {
            gfc_error ("Character '%s' in string at %L cannot be converted "
                       "into character kind %d",
                       gfc_print_wide_char (result->value.character.string[i]),
                       &e->where, kind);
            return &gfc_bad_expr;
          }
 
      return result;
    }
  else if (e->expr_type == EXPR_ARRAY)
    {
      /* For an array constructor, we convert each constructor element.  */
      gfc_constructor *head = NULL, *tail = NULL, *c;
 
      for (c = e->value.constructor; c; c = c->next)
        {
          if (head == NULL)
            head = tail = gfc_get_constructor ();
          else
            {
              tail->next = gfc_get_constructor ();
              tail = tail->next;
            }
 
          tail->where = c->where;
          tail->expr = gfc_convert_char_constant (c->expr, type, kind);
          if (tail->expr == &gfc_bad_expr)
            {
              tail->expr = NULL;
              return &gfc_bad_expr;
            }
 
          if (tail->expr == NULL)
            {
              gfc_free_constructor (head);
              return NULL;
            }
        }
 
      result = gfc_get_expr ();
      result->ts.type = type;
      result->ts.kind = kind;
      result->expr_type = EXPR_ARRAY;
      result->value.constructor = head;
      result->shape = gfc_copy_shape (e->shape, e->rank);
      result->where = e->where;
      result->rank = e->rank;
      result->ts.u.cl = e->ts.u.cl;
 
      return result;
    }
  else
    return NULL;
}
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[/] [openrisc/] [trunk/] [gnu-stable/] [gcc-4.5.1/] [gcc/] [fortran/] [simplify.c] - Blame information for rev 826

Line No.	Rev	Author	Line
1	285	jeremybenn	`/* Simplify intrinsic functions at compile-time.`
2			`Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009`
3			`Free Software Foundation, Inc.`
4			`Contributed by Andy Vaught & Katherine Holcomb`
5
6			`This file is part of GCC.`
7
8			`GCC is free software; you can redistribute it and/or modify it under`
9			`the terms of the GNU General Public License as published by the Free`
10			`Software Foundation; either version 3, or (at your option) any later`
11			`version.`
12
13			`GCC is distributed in the hope that it will be useful, but WITHOUT ANY`
14			`WARRANTY; without even the implied warranty of MERCHANTABILITY or`
15			`FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License`
16			`for more details.`
17
18			`You should have received a copy of the GNU General Public License`
19			`along with GCC; see the file COPYING3. If not see`
20			`<http://www.gnu.org/licenses/>. */`
21
22			`#include "config.h"`
23			`#include "system.h"`
24			`#include "flags.h"`
25			`#include "gfortran.h"`
26			`#include "arith.h"`
27			`#include "intrinsic.h"`
28			`#include "target-memory.h"`
29
30			`/* Savely advance an array constructor by 'n' elements.`
31			`Mainly used by simplifiers of transformational intrinsics. */`
32			`#define ADVANCE(ctor, n) do { int i; for (i = 0; i < n && ctor; ++i) ctor = ctor->next; } while (0)`
33
34			`gfc_expr gfc_bad_expr;`
35
36
37			`/* Note that 'simplification' is not just transforming expressions.`
38			`For functions that are not simplified at compile time, range`
39			`checking is done if possible.`
40