gcc/tree-vrp.c

/* Support routines for Value Range Propagation (VRP).
   Copyright (C) 2005-2019 Free Software Foundation, Inc.
   Contributed by Diego Novillo <dnovillo@redhat.com>.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.

GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "backend.h"
#include "insn-codes.h"
#include "rtl.h"
#include "tree.h"
#include "gimple.h"
#include "cfghooks.h"
#include "tree-pass.h"
#include "ssa.h"
#include "optabs-tree.h"
#include "gimple-pretty-print.h"
#include "diagnostic-core.h"
#include "flags.h"
#include "fold-const.h"
#include "stor-layout.h"
#include "calls.h"
#include "cfganal.h"
#include "gimple-fold.h"
#include "tree-eh.h"
#include "gimple-iterator.h"
#include "gimple-walk.h"
#include "tree-cfg.h"
#include "tree-dfa.h"
#include "tree-ssa-loop-manip.h"
#include "tree-ssa-loop-niter.h"
#include "tree-ssa-loop.h"
#include "tree-into-ssa.h"
#include "tree-ssa.h"
#include "intl.h"
#include "cfgloop.h"
#include "tree-scalar-evolution.h"
#include "tree-ssa-propagate.h"
#include "tree-chrec.h"
#include "tree-ssa-threadupdate.h"
#include "tree-ssa-scopedtables.h"
#include "tree-ssa-threadedge.h"
#include "omp-general.h"
#include "target.h"
#include "case-cfn-macros.h"
#include "params.h"
#include "alloc-pool.h"
#include "domwalk.h"
#include "tree-cfgcleanup.h"
#include "stringpool.h"
#include "attribs.h"
#include "vr-values.h"
#include "builtins.h"
#include "wide-int-range.h"

/* Set of SSA names found live during the RPO traversal of the function
   for still active basic-blocks.  */
static sbitmap *live;

void
value_range_base::set (enum value_range_kind kind, tree min, tree max)
{
  m_kind = kind;
  m_min = min;
  m_max = max;
  if (flag_checking)
    check ();
}

void
value_range::set_equiv (bitmap equiv)
{
  /* Since updating the equivalence set involves deep copying the
     bitmaps, only do it if absolutely necessary.

     All equivalence bitmaps are allocated from the same obstack.  So
     we can use the obstack associated with EQUIV to allocate vr->equiv.  */
  if (m_equiv == NULL
      && equiv != NULL)
    m_equiv = BITMAP_ALLOC (equiv->obstack);

  if (equiv != m_equiv)
    {
      if (equiv && !bitmap_empty_p (equiv))
	bitmap_copy (m_equiv, equiv);
      else
	bitmap_clear (m_equiv);
    }
}

/* Initialize value_range.  */

void
value_range::set (enum value_range_kind kind, tree min, tree max,
		  bitmap equiv)
{
  value_range_base::set (kind, min, max);
  set_equiv (equiv);
  if (flag_checking)
    check ();
}

value_range_base::value_range_base (value_range_kind kind, tree min, tree max)
{
  set (kind, min, max);
}

value_range::value_range (value_range_kind kind, tree min, tree max,
			  bitmap equiv)
{
  m_equiv = NULL;
  set (kind, min, max, equiv);
}

value_range::value_range (const value_range_base &other)
{
  m_equiv = NULL;
  set (other.kind (), other.min(), other.max (), NULL);
}

/* Like set, but keep the equivalences in place.  */

void
value_range::update (value_range_kind kind, tree min, tree max)
{
  set (kind, min, max,
       (kind != VR_UNDEFINED && kind != VR_VARYING) ? m_equiv : NULL);
}

/* Copy value_range in FROM into THIS while avoiding bitmap sharing.

   Note: The code that avoids the bitmap sharing looks at the existing
   this->m_equiv, so this function cannot be used to initalize an
   object.  Use the constructors for initialization.  */

void
value_range::deep_copy (const value_range *from)
{
  set (from->m_kind, from->min (), from->max (), from->m_equiv);
}

void
value_range::move (value_range *from)
{
  set (from->m_kind, from->min (), from->max ());
  m_equiv = from->m_equiv;
  from->m_equiv = NULL;
}

/* Check the validity of the range.  */

void
value_range_base::check ()
{
  switch (m_kind)
    {
    case VR_RANGE:
    case VR_ANTI_RANGE:
      {
	int cmp;

	gcc_assert (m_min && m_max);

	gcc_assert (!TREE_OVERFLOW_P (m_min) && !TREE_OVERFLOW_P (m_max));

	/* Creating ~[-MIN, +MAX] is stupid because that would be
	   the empty set.  */
	if (INTEGRAL_TYPE_P (TREE_TYPE (m_min)) && m_kind == VR_ANTI_RANGE)
	  gcc_assert (!vrp_val_is_min (m_min) || !vrp_val_is_max (m_max));

	cmp = compare_values (m_min, m_max);
	gcc_assert (cmp == 0 || cmp == -1 || cmp == -2);
	break;
      }
    case VR_UNDEFINED:
    case VR_VARYING:
      gcc_assert (!min () && !max ());
      break;
    default:
      gcc_unreachable ();
    }
}

void
value_range::check ()
{
  value_range_base::check ();
  switch (m_kind)
    {
    case VR_UNDEFINED:
    case VR_VARYING:
      gcc_assert (!m_equiv || bitmap_empty_p (m_equiv));
    default:;
    }
}

/* Equality operator.  We purposely do not overload ==, to avoid
   confusion with the equality bitmap in the derived value_range
   class.  */

bool
value_range_base::equal_p (const value_range_base &other) const
{
  return (m_kind == other.m_kind
	  && vrp_operand_equal_p (m_min, other.m_min)
	  && vrp_operand_equal_p (m_max, other.m_max));
}

/* Returns TRUE if THIS == OTHER.  Ignores the equivalence bitmap if
   IGNORE_EQUIVS is TRUE.  */

bool
value_range::equal_p (const value_range &other, bool ignore_equivs) const
{
  return (value_range_base::equal_p (other)
	  && (ignore_equivs
	      || vrp_bitmap_equal_p (m_equiv, other.m_equiv)));
}

/* Return TRUE if this is a symbolic range.  */

bool
value_range_base::symbolic_p () const
{
  return (!varying_p ()
	  && !undefined_p ()
	  && (!is_gimple_min_invariant (m_min)
	      || !is_gimple_min_invariant (m_max)));
}

/* NOTE: This is not the inverse of symbolic_p because the range
   could also be varying or undefined.  Ideally they should be inverse
   of each other, with varying only applying to symbolics.  Varying of
   constants would be represented as [-MIN, +MAX].  */

bool
value_range_base::constant_p () const
{
  return (!varying_p ()
	  && !undefined_p ()
	  && TREE_CODE (m_min) == INTEGER_CST
	  && TREE_CODE (m_max) == INTEGER_CST);
}

void
value_range_base::set_undefined ()
{
  set (VR_UNDEFINED, NULL, NULL);
}

void
value_range::set_undefined ()
{
  set (VR_UNDEFINED, NULL, NULL, NULL);
}

void
value_range_base::set_varying ()
{
  set (VR_VARYING, NULL, NULL);
}

void
value_range::set_varying ()
{
  set (VR_VARYING, NULL, NULL, NULL);
}

/* Return TRUE if it is possible that range contains VAL.  */

bool
value_range_base::may_contain_p (tree val) const
{
  if (varying_p ())
    return true;

  if (undefined_p ())
    return true;

  if (m_kind == VR_ANTI_RANGE)
    {
      int res = value_inside_range (val, min (), max ());
      return res == 0 || res == -2;
    }
  return value_inside_range (val, min (), max ()) != 0;
}

void
value_range::equiv_clear ()
{
  if (m_equiv)
    bitmap_clear (m_equiv);
}

/* Add VAR and VAR's equivalence set (VAR_VR) to the equivalence
   bitmap.  If no equivalence table has been created, OBSTACK is the
   obstack to use (NULL for the default obstack).

   This is the central point where equivalence processing can be
   turned on/off.  */

void
value_range::equiv_add (const_tree var,
			const value_range *var_vr,
			bitmap_obstack *obstack)
{
  if (!m_equiv)
    m_equiv = BITMAP_ALLOC (obstack);
  unsigned ver = SSA_NAME_VERSION (var);
  bitmap_set_bit (m_equiv, ver);
  if (var_vr && var_vr->m_equiv)
    bitmap_ior_into (m_equiv, var_vr->m_equiv);
}

/* If range is a singleton, place it in RESULT and return TRUE.
   Note: A singleton can be any gimple invariant, not just constants.
   So, [&x, &x] counts as a singleton.  */

bool
value_range_base::singleton_p (tree *result) const
{
  if (m_kind == VR_RANGE
      && vrp_operand_equal_p (min (), max ())
      && is_gimple_min_invariant (min ()))
    {
      if (result)
        *result = min ();
      return true;
    }
  return false;
}

tree
value_range_base::type () const
{
  /* Types are only valid for VR_RANGE and VR_ANTI_RANGE, which are
     known to have non-zero min/max.  */
  gcc_assert (min ());
  return TREE_TYPE (min ());
}

void
value_range_base::dump (FILE *file) const
{
  if (undefined_p ())
    fprintf (file, "UNDEFINED");
  else if (m_kind == VR_RANGE || m_kind == VR_ANTI_RANGE)
    {
      tree ttype = type ();

      print_generic_expr (file, ttype);
      fprintf (file, " ");

      fprintf (file, "%s[", (m_kind == VR_ANTI_RANGE) ? "~" : "");

      if (INTEGRAL_TYPE_P (ttype)
	  && !TYPE_UNSIGNED (ttype)
	  && vrp_val_is_min (min ())
	  && TYPE_PRECISION (ttype) != 1)
	fprintf (file, "-INF");
      else
	print_generic_expr (file, min ());

      fprintf (file, ", ");

      if (INTEGRAL_TYPE_P (ttype)
	  && vrp_val_is_max (max ())
	  && TYPE_PRECISION (ttype) != 1)
	fprintf (file, "+INF");
      else
	print_generic_expr (file, max ());

      fprintf (file, "]");
    }
  else if (varying_p ())
    fprintf (file, "VARYING");
  else
    gcc_unreachable ();
}

void
value_range::dump (FILE *file) const
{
  value_range_base::dump (file);
  if ((m_kind == VR_RANGE || m_kind == VR_ANTI_RANGE)
      && m_equiv)
    {
      bitmap_iterator bi;
      unsigned i, c = 0;

      fprintf (file, "  EQUIVALENCES: { ");

      EXECUTE_IF_SET_IN_BITMAP (m_equiv, 0, i, bi)
	{
	  print_generic_expr (file, ssa_name (i));
	  fprintf (file, " ");
	  c++;
	}

      fprintf (file, "} (%u elements)", c);
    }
}

void
dump_value_range (FILE *file, const value_range *vr)
{
  if (!vr)
    fprintf (file, "[]");
  else
    vr->dump (file);
}

void
dump_value_range (FILE *file, const value_range_base *vr)
{
  if (!vr)
    fprintf (file, "[]");
  else
    vr->dump (file);
}

DEBUG_FUNCTION void
debug (const value_range_base *vr)
{
  dump_value_range (stderr, vr);
}

DEBUG_FUNCTION void
debug (const value_range_base &vr)
{
  dump_value_range (stderr, &vr);
}

DEBUG_FUNCTION void
debug (const value_range *vr)
{
  dump_value_range (stderr, vr);
}

DEBUG_FUNCTION void
debug (const value_range &vr)
{
  dump_value_range (stderr, &vr);
}

/* Return true if the SSA name NAME is live on the edge E.  */

static bool
live_on_edge (edge e, tree name)
{
  return (live[e->dest->index]
	  && bitmap_bit_p (live[e->dest->index], SSA_NAME_VERSION (name)));
}

/* Location information for ASSERT_EXPRs.  Each instance of this
   structure describes an ASSERT_EXPR for an SSA name.  Since a single
   SSA name may have more than one assertion associated with it, these
   locations are kept in a linked list attached to the corresponding
   SSA name.  */
struct assert_locus
{
  /* Basic block where the assertion would be inserted.  */
  basic_block bb;

  /* Some assertions need to be inserted on an edge (e.g., assertions
     generated by COND_EXPRs).  In those cases, BB will be NULL.  */
  edge e;

  /* Pointer to the statement that generated this assertion.  */
  gimple_stmt_iterator si;

  /* Predicate code for the ASSERT_EXPR.  Must be COMPARISON_CLASS_P.  */
  enum tree_code comp_code;

  /* Value being compared against.  */
  tree val;

  /* Expression to compare.  */
  tree expr;

  /* Next node in the linked list.  */
  assert_locus *next;
};

/* If bit I is present, it means that SSA name N_i has a list of
   assertions that should be inserted in the IL.  */
static bitmap need_assert_for;

/* Array of locations lists where to insert assertions.  ASSERTS_FOR[I]
   holds a list of ASSERT_LOCUS_T nodes that describe where
   ASSERT_EXPRs for SSA name N_I should be inserted.  */
static assert_locus **asserts_for;

/* Return the maximum value for TYPE.  */

tree
vrp_val_max (const_tree type)
{
  if (!INTEGRAL_TYPE_P (type))
    return NULL_TREE;

  return TYPE_MAX_VALUE (type);
}

/* Return the minimum value for TYPE.  */

tree
vrp_val_min (const_tree type)
{
  if (!INTEGRAL_TYPE_P (type))
    return NULL_TREE;

  return TYPE_MIN_VALUE (type);
}

/* Return whether VAL is equal to the maximum value of its type.
   We can't do a simple equality comparison with TYPE_MAX_VALUE because
   C typedefs and Ada subtypes can produce types whose TYPE_MAX_VALUE
   is not == to the integer constant with the same value in the type.  */

bool
vrp_val_is_max (const_tree val)
{
  tree type_max = vrp_val_max (TREE_TYPE (val));
  return (val == type_max
	  || (type_max != NULL_TREE
	      && operand_equal_p (val, type_max, 0)));
}

/* Return whether VAL is equal to the minimum value of its type.  */

bool
vrp_val_is_min (const_tree val)
{
  tree type_min = vrp_val_min (TREE_TYPE (val));
  return (val == type_min
	  || (type_min != NULL_TREE
	      && operand_equal_p (val, type_min, 0)));
}

/* VR_TYPE describes a range with mininum value *MIN and maximum
   value *MAX.  Restrict the range to the set of values that have
   no bits set outside NONZERO_BITS.  Update *MIN and *MAX and
   return the new range type.

   SGN gives the sign of the values described by the range.  */

enum value_range_kind
intersect_range_with_nonzero_bits (enum value_range_kind vr_type,
				   wide_int *min, wide_int *max,
				   const wide_int &nonzero_bits,
				   signop sgn)
{
  if (vr_type == VR_ANTI_RANGE)
    {
      /* The VR_ANTI_RANGE is equivalent to the union of the ranges
	 A: [-INF, *MIN) and B: (*MAX, +INF].  First use NONZERO_BITS
	 to create an inclusive upper bound for A and an inclusive lower
	 bound for B.  */
      wide_int a_max = wi::round_down_for_mask (*min - 1, nonzero_bits);
      wide_int b_min = wi::round_up_for_mask (*max + 1, nonzero_bits);

      /* If the calculation of A_MAX wrapped, A is effectively empty
	 and A_MAX is the highest value that satisfies NONZERO_BITS.
	 Likewise if the calculation of B_MIN wrapped, B is effectively
	 empty and B_MIN is the lowest value that satisfies NONZERO_BITS.  */
      bool a_empty = wi::ge_p (a_max, *min, sgn);
      bool b_empty = wi::le_p (b_min, *max, sgn);

      /* If both A and B are empty, there are no valid values.  */
      if (a_empty && b_empty)
	return VR_UNDEFINED;

      /* If exactly one of A or B is empty, return a VR_RANGE for the
	 other one.  */
      if (a_empty || b_empty)
	{
	  *min = b_min;
	  *max = a_max;
	  gcc_checking_assert (wi::le_p (*min, *max, sgn));
	  return VR_RANGE;
	}

      /* Update the VR_ANTI_RANGE bounds.  */
      *min = a_max + 1;
      *max = b_min - 1;
      gcc_checking_assert (wi::le_p (*min, *max, sgn));

      /* Now check whether the excluded range includes any values that
	 satisfy NONZERO_BITS.  If not, switch to a full VR_RANGE.  */
      if (wi::round_up_for_mask (*min, nonzero_bits) == b_min)
	{
	  unsigned int precision = min->get_precision ();
	  *min = wi::min_value (precision, sgn);
	  *max = wi::max_value (precision, sgn);
	  vr_type = VR_RANGE;
	}
    }
  if (vr_type == VR_RANGE)
    {
      *max = wi::round_down_for_mask (*max, nonzero_bits);

      /* Check that the range contains at least one valid value.  */
      if (wi::gt_p (*min, *max, sgn))
	return VR_UNDEFINED;

      *min = wi::round_up_for_mask (*min, nonzero_bits);
      gcc_checking_assert (wi::le_p (*min, *max, sgn));
    }
  return vr_type;
}


/* Set value range to the canonical form of {VRTYPE, MIN, MAX, EQUIV}.
   This means adjusting VRTYPE, MIN and MAX representing the case of a
   wrapping range with MAX < MIN covering [MIN, type_max] U [type_min, MAX]
   as anti-rage ~[MAX+1, MIN-1].  Likewise for wrapping anti-ranges.
   In corner cases where MAX+1 or MIN-1 wraps this will fall back
   to varying.
   This routine exists to ease canonicalization in the case where we
   extract ranges from var + CST op limit.  */

void
value_range_base::set_and_canonicalize (enum value_range_kind kind,
					tree min, tree max)
{
  /* Use the canonical setters for VR_UNDEFINED and VR_VARYING.  */
  if (kind == VR_UNDEFINED)
    {
      set_undefined ();
      return;
    }
  else if (kind == VR_VARYING)
    {
      set_varying ();
      return;
    }

  /* Nothing to canonicalize for symbolic ranges.  */
  if (TREE_CODE (min) != INTEGER_CST
      || TREE_CODE (max) != INTEGER_CST)
    {
      set (kind, min, max);
      return;
    }

  /* Wrong order for min and max, to swap them and the VR type we need
     to adjust them.  */
  if (tree_int_cst_lt (max, min))
    {
      tree one, tmp;

      /* For one bit precision if max < min, then the swapped
	 range covers all values, so for VR_RANGE it is varying and
	 for VR_ANTI_RANGE empty range, so drop to varying as well.  */
      if (TYPE_PRECISION (TREE_TYPE (min)) == 1)
	{
	  set_varying ();
	  return;
	}

      one = build_int_cst (TREE_TYPE (min), 1);
      tmp = int_const_binop (PLUS_EXPR, max, one);
      max = int_const_binop (MINUS_EXPR, min, one);
      min = tmp;

      /* There's one corner case, if we had [C+1, C] before we now have
	 that again.  But this represents an empty value range, so drop
	 to varying in this case.  */
      if (tree_int_cst_lt (max, min))
	{
	  set_varying ();
	  return;
	}

      kind = kind == VR_RANGE ? VR_ANTI_RANGE : VR_RANGE;
    }

  /* Anti-ranges that can be represented as ranges should be so.  */
  if (kind == VR_ANTI_RANGE)
    {
      /* For -fstrict-enums we may receive out-of-range ranges so consider
         values < -INF and values > INF as -INF/INF as well.  */
      tree type = TREE_TYPE (min);
      bool is_min = (INTEGRAL_TYPE_P (type)
		     && tree_int_cst_compare (min, TYPE_MIN_VALUE (type)) <= 0);
      bool is_max = (INTEGRAL_TYPE_P (type)
		     && tree_int_cst_compare (max, TYPE_MAX_VALUE (type)) >= 0);

      if (is_min && is_max)
	{
	  /* We cannot deal with empty ranges, drop to varying.
	     ???  This could be VR_UNDEFINED instead.  */
	  set_varying ();
	  return;
	}
      else if (TYPE_PRECISION (TREE_TYPE (min)) == 1
	       && (is_min || is_max))
	{
	  /* Non-empty boolean ranges can always be represented
	     as a singleton range.  */
	  if (is_min)
	    min = max = vrp_val_max (TREE_TYPE (min));
	  else
	    min = max = vrp_val_min (TREE_TYPE (min));
	  kind = VR_RANGE;
	}
      else if (is_min
	       /* As a special exception preserve non-null ranges.  */
	       && !(TYPE_UNSIGNED (TREE_TYPE (min))
		    && integer_zerop (max)))
        {
	  tree one = build_int_cst (TREE_TYPE (max), 1);
	  min = int_const_binop (PLUS_EXPR, max, one);
	  max = vrp_val_max (TREE_TYPE (max));
	  kind = VR_RANGE;
        }
      else if (is_max)
        {
	  tree one = build_int_cst (TREE_TYPE (min), 1);
	  max = int_const_binop (MINUS_EXPR, min, one);
	  min = vrp_val_min (TREE_TYPE (min));
	  kind = VR_RANGE;
        }
    }

  /* Do not drop [-INF(OVF), +INF(OVF)] to varying.  (OVF) has to be sticky
     to make sure VRP iteration terminates, otherwise we can get into
     oscillations.  */

  set (kind, min, max);
}

void
value_range::set_and_canonicalize (enum value_range_kind kind,
				   tree min, tree max, bitmap equiv)
{
  value_range_base::set_and_canonicalize (kind, min, max);
  if (this->kind () == VR_RANGE || this->kind () == VR_ANTI_RANGE)
    set_equiv (equiv);
  else
    equiv_clear ();
}

void
value_range_base::set (tree val)
{
  gcc_assert (TREE_CODE (val) == SSA_NAME || is_gimple_min_invariant (val));
  if (TREE_OVERFLOW_P (val))
    val = drop_tree_overflow (val);
  set (VR_RANGE, val, val);
}

void
value_range::set (tree val)
{
  gcc_assert (TREE_CODE (val) == SSA_NAME || is_gimple_min_invariant (val));
  if (TREE_OVERFLOW_P (val))
    val = drop_tree_overflow (val);
  set (VR_RANGE, val, val, NULL);
}

/* Set value range VR to a non-NULL range of type TYPE.  */

void
value_range_base::set_nonnull (tree type)
{
  tree zero = build_int_cst (type, 0);
  set (VR_ANTI_RANGE, zero, zero);
}

void
value_range::set_nonnull (tree type)
{
  tree zero = build_int_cst (type, 0);
  set (VR_ANTI_RANGE, zero, zero, NULL);
}

/* Set value range VR to a NULL range of type TYPE.  */

void
value_range_base::set_null (tree type)
{
  set (build_int_cst (type, 0));
}

void
value_range::set_null (tree type)
{
  set (build_int_cst (type, 0));
}

/* Return true, if VAL1 and VAL2 are equal values for VRP purposes.  */

bool
vrp_operand_equal_p (const_tree val1, const_tree val2)
{
  if (val1 == val2)
    return true;
  if (!val1 || !val2 || !operand_equal_p (val1, val2, 0))
    return false;
  return true;
}

/* Return true, if the bitmaps B1 and B2 are equal.  */

bool
vrp_bitmap_equal_p (const_bitmap b1, const_bitmap b2)
{
  return (b1 == b2
	  || ((!b1 || bitmap_empty_p (b1))
	      && (!b2 || bitmap_empty_p (b2)))
	  || (b1 && b2
	      && bitmap_equal_p (b1, b2)));
}

/* Return true if VR is [0, 0].  */

static inline bool
range_is_null (const value_range_base *vr)
{
  return vr->zero_p ();
}

static inline bool
range_is_nonnull (const value_range_base *vr)
{
  return (vr->kind () == VR_ANTI_RANGE
	  && vr->min () == vr->max ()
	  && integer_zerop (vr->min ()));
}

/* Return true if max and min of VR are INTEGER_CST.  It's not necessary
   a singleton.  */

bool
range_int_cst_p (const value_range_base *vr)
{
  return (vr->kind () == VR_RANGE
	  && TREE_CODE (vr->min ()) == INTEGER_CST
	  && TREE_CODE (vr->max ()) == INTEGER_CST);
}

/* Return true if VR is a INTEGER_CST singleton.  */

bool
range_int_cst_singleton_p (const value_range_base *vr)
{
  return (range_int_cst_p (vr)
	  && tree_int_cst_equal (vr->min (), vr->max ()));
}

/* Return the single symbol (an SSA_NAME) contained in T if any, or NULL_TREE
   otherwise.  We only handle additive operations and set NEG to true if the
   symbol is negated and INV to the invariant part, if any.  */

tree
get_single_symbol (tree t, bool *neg, tree *inv)
{
  bool neg_;
  tree inv_;

  *inv = NULL_TREE;
  *neg = false;

  if (TREE_CODE (t) == PLUS_EXPR
      || TREE_CODE (t) == POINTER_PLUS_EXPR
      || TREE_CODE (t) == MINUS_EXPR)
    {
      if (is_gimple_min_invariant (TREE_OPERAND (t, 0)))
	{
	  neg_ = (TREE_CODE (t) == MINUS_EXPR);
	  inv_ = TREE_OPERAND (t, 0);
	  t = TREE_OPERAND (t, 1);
	}
      else if (is_gimple_min_invariant (TREE_OPERAND (t, 1)))
	{
	  neg_ = false;
	  inv_ = TREE_OPERAND (t, 1);
	  t = TREE_OPERAND (t, 0);
	}
      else
        return NULL_TREE;
    }
  else
    {
      neg_ = false;
      inv_ = NULL_TREE;
    }

  if (TREE_CODE (t) == NEGATE_EXPR)
    {
      t = TREE_OPERAND (t, 0);
      neg_ = !neg_;
    }

  if (TREE_CODE (t) != SSA_NAME)
    return NULL_TREE;

  if (inv_ && TREE_OVERFLOW_P (inv_))
    inv_ = drop_tree_overflow (inv_);

  *neg = neg_;
  *inv = inv_;
  return t;
}

/* The reverse operation: build a symbolic expression with TYPE
   from symbol SYM, negated according to NEG, and invariant INV.  */

static tree
build_symbolic_expr (tree type, tree sym, bool neg, tree inv)
{
  const bool pointer_p = POINTER_TYPE_P (type);
  tree t = sym;

  if (neg)
    t = build1 (NEGATE_EXPR, type, t);

  if (integer_zerop (inv))
    return t;

  return build2 (pointer_p ? POINTER_PLUS_EXPR : PLUS_EXPR, type, t, inv);
}

/* Return
   1 if VAL < VAL2
   0 if !(VAL < VAL2)
   -2 if those are incomparable.  */
int
operand_less_p (tree val, tree val2)
{
  /* LT is folded faster than GE and others.  Inline the common case.  */
  if (TREE_CODE (val) == INTEGER_CST && TREE_CODE (val2) == INTEGER_CST)
    return tree_int_cst_lt (val, val2);
  else
    {
      tree tcmp;

      fold_defer_overflow_warnings ();

      tcmp = fold_binary_to_constant (LT_EXPR, boolean_type_node, val, val2);

      fold_undefer_and_ignore_overflow_warnings ();

      if (!tcmp
	  || TREE_CODE (tcmp) != INTEGER_CST)
	return -2;

      if (!integer_zerop (tcmp))
	return 1;
    }

  return 0;
}

/* Compare two values VAL1 and VAL2.  Return

   	-2 if VAL1 and VAL2 cannot be compared at compile-time,
   	-1 if VAL1 < VAL2,
   	 0 if VAL1 == VAL2,
	+1 if VAL1 > VAL2, and
	+2 if VAL1 != VAL2

   This is similar to tree_int_cst_compare but supports pointer values
   and values that cannot be compared at compile time.

   If STRICT_OVERFLOW_P is not NULL, then set *STRICT_OVERFLOW_P to
   true if the return value is only valid if we assume that signed
   overflow is undefined.  */

int
compare_values_warnv (tree val1, tree val2, bool *strict_overflow_p)
{
  if (val1 == val2)
    return 0;

  /* Below we rely on the fact that VAL1 and VAL2 are both pointers or
     both integers.  */
  gcc_assert (POINTER_TYPE_P (TREE_TYPE (val1))
	      == POINTER_TYPE_P (TREE_TYPE (val2)));

  /* Convert the two values into the same type.  This is needed because
     sizetype causes sign extension even for unsigned types.  */
  val2 = fold_convert (TREE_TYPE (val1), val2);
  STRIP_USELESS_TYPE_CONVERSION (val2);

  const bool overflow_undefined
    = INTEGRAL_TYPE_P (TREE_TYPE (val1))
      && TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (val1));
  tree inv1, inv2;
  bool neg1, neg2;
  tree sym1 = get_single_symbol (val1, &neg1, &inv1);
  tree sym2 = get_single_symbol (val2, &neg2, &inv2);

  /* If VAL1 and VAL2 are of the form '[-]NAME [+ CST]', return -1 or +1
     accordingly.  If VAL1 and VAL2 don't use the same name, return -2.  */
  if (sym1 && sym2)
    {
      /* Both values must use the same name with the same sign.  */
      if (sym1 != sym2 || neg1 != neg2)
	return -2;

      /* [-]NAME + CST == [-]NAME + CST.  */
      if (inv1 == inv2)
	return 0;

      /* If overflow is defined we cannot simplify more.  */
      if (!overflow_undefined)
	return -2;

      if (strict_overflow_p != NULL
	  /* Symbolic range building sets TREE_NO_WARNING to declare
	     that overflow doesn't happen.  */
	  && (!inv1 || !TREE_NO_WARNING (val1))
	  && (!inv2 || !TREE_NO_WARNING (val2)))
	*strict_overflow_p = true;

      if (!inv1)
	inv1 = build_int_cst (TREE_TYPE (val1), 0);
      if (!inv2)
	inv2 = build_int_cst (TREE_TYPE (val2), 0);

      return wi::cmp (wi::to_wide (inv1), wi::to_wide (inv2),
		      TYPE_SIGN (TREE_TYPE (val1)));
    }

  const bool cst1 = is_gimple_min_invariant (val1);
  const bool cst2 = is_gimple_min_invariant (val2);

  /* If one is of the form '[-]NAME + CST' and the other is constant, then
     it might be possible to say something depending on the constants.  */
  if ((sym1 && inv1 && cst2) || (sym2 && inv2 && cst1))
    {
      if (!overflow_undefined)
	return -2;

      if (strict_overflow_p != NULL
	  /* Symbolic range building sets TREE_NO_WARNING to declare
	     that overflow doesn't happen.  */
	  && (!sym1 || !TREE_NO_WARNING (val1))
	  && (!sym2 || !TREE_NO_WARNING (val2)))
	*strict_overflow_p = true;

      const signop sgn = TYPE_SIGN (TREE_TYPE (val1));
      tree cst = cst1 ? val1 : val2;
      tree inv = cst1 ? inv2 : inv1;

      /* Compute the difference between the constants.  If it overflows or
	 underflows, this means that we can trivially compare the NAME with
	 it and, consequently, the two values with each other.  */
      wide_int diff = wi::to_wide (cst) - wi::to_wide (inv);
      if (wi::cmp (0, wi::to_wide (inv), sgn)
	  != wi::cmp (diff, wi::to_wide (cst), sgn))
	{
	  const int res = wi::cmp (wi::to_wide (cst), wi::to_wide (inv), sgn);
	  return cst1 ? res : -res;
	}

      return -2;
    }

  /* We cannot say anything more for non-constants.  */
  if (!cst1 || !cst2)
    return -2;

  if (!POINTER_TYPE_P (TREE_TYPE (val1)))
    {
      /* We cannot compare overflowed values.  */
      if (TREE_OVERFLOW (val1) || TREE_OVERFLOW (val2))
	return -2;

      if (TREE_CODE (val1) == INTEGER_CST
	  && TREE_CODE (val2) == INTEGER_CST)
	return tree_int_cst_compare (val1, val2);

      if (poly_int_tree_p (val1) && poly_int_tree_p (val2))
	{
	  if (known_eq (wi::to_poly_widest (val1),
			wi::to_poly_widest (val2)))
	    return 0;
	  if (known_lt (wi::to_poly_widest (val1),
			wi::to_poly_widest (val2)))
	    return -1;
	  if (known_gt (wi::to_poly_widest (val1),
			wi::to_poly_widest (val2)))
	    return 1;
	}

      return -2;
    }
  else
    {
      tree t;

      /* First see if VAL1 and VAL2 are not the same.  */
      if (val1 == val2 || operand_equal_p (val1, val2, 0))
	return 0;

      /* If VAL1 is a lower address than VAL2, return -1.  */
      if (operand_less_p (val1, val2) == 1)
	return -1;

      /* If VAL1 is a higher address than VAL2, return +1.  */
      if (operand_less_p (val2, val1) == 1)
	return 1;

      /* If VAL1 is different than VAL2, return +2.
	 For integer constants we either have already returned -1 or 1
	 or they are equivalent.  We still might succeed in proving
	 something about non-trivial operands.  */
      if (TREE_CODE (val1) != INTEGER_CST
	  || TREE_CODE (val2) != INTEGER_CST)
	{
          t = fold_binary_to_constant (NE_EXPR, boolean_type_node, val1, val2);
	  if (t && integer_onep (t))
	    return 2;
	}

      return -2;
    }
}

/* Compare values like compare_values_warnv.  */

int
compare_values (tree val1, tree val2)
{
  bool sop;
  return compare_values_warnv (val1, val2, &sop);
}


/* Return 1 if VAL is inside value range MIN <= VAL <= MAX,
          0 if VAL is not inside [MIN, MAX],
	 -2 if we cannot tell either way.

   Benchmark compile/20001226-1.c compilation time after changing this
   function.  */

int
value_inside_range (tree val, tree min, tree max)
{
  int cmp1, cmp2;

  cmp1 = operand_less_p (val, min);
  if (cmp1 == -2)
    return -2;
  if (cmp1 == 1)
    return 0;

  cmp2 = operand_less_p (max, val);
  if (cmp2 == -2)
    return -2;

  return !cmp2;
}


/* Return TRUE if *VR includes the value X.  */

bool
range_includes_p (const value_range_base *vr, HOST_WIDE_INT x)
{
  if (vr->varying_p () || vr->undefined_p ())
    return true;
  return vr->may_contain_p (build_int_cst (vr->type (), x));
}

/* If *VR has a value range that is a single constant value return that,
   otherwise return NULL_TREE.

   ?? This actually returns TRUE for [&x, &x], so perhaps "constant"
   is not the best name.  */

tree
value_range_constant_singleton (const value_range_base *vr)
{
  tree result = NULL;
  if (vr->singleton_p (&result))
    return result;
  return NULL;
}

/* Value range wrapper for wide_int_range_set_zero_nonzero_bits.

   Compute MAY_BE_NONZERO and MUST_BE_NONZERO bit masks for range in VR.

   Return TRUE if VR was a constant range and we were able to compute
   the bit masks.  */

bool
vrp_set_zero_nonzero_bits (const tree expr_type,
			   const value_range_base *vr,
			   wide_int *may_be_nonzero,
			   wide_int *must_be_nonzero)
{
  if (!range_int_cst_p (vr))
    {
      *may_be_nonzero = wi::minus_one (TYPE_PRECISION (expr_type));
      *must_be_nonzero = wi::zero (TYPE_PRECISION (expr_type));
      return false;
    }
  wide_int_range_set_zero_nonzero_bits (TYPE_SIGN (expr_type),
					wi::to_wide (vr->min ()),
					wi::to_wide (vr->max ()),
					*may_be_nonzero, *must_be_nonzero);
  return true;
}

/* Create two value-ranges in *VR0 and *VR1 from the anti-range *AR
   so that *VR0 U *VR1 == *AR.  Returns true if that is possible,
   false otherwise.  If *AR can be represented with a single range
   *VR1 will be VR_UNDEFINED.  */

static bool
ranges_from_anti_range (const value_range_base *ar,
			value_range_base *vr0, value_range_base *vr1)
{
  tree type = ar->type ();

  vr0->set_undefined ();
  vr1->set_undefined ();

  /* As a future improvement, we could handle ~[0, A] as: [-INF, -1] U
     [A+1, +INF].  Not sure if this helps in practice, though.  */

  if (ar->kind () != VR_ANTI_RANGE
      || TREE_CODE (ar->min ()) != INTEGER_CST
      || TREE_CODE (ar->max ()) != INTEGER_CST
      || !vrp_val_min (type)
      || !vrp_val_max (type))
    return false;

  if (tree_int_cst_lt (vrp_val_min (type), ar->min ()))
    vr0->set (VR_RANGE,
	      vrp_val_min (type),
	      wide_int_to_tree (type, wi::to_wide (ar->min ()) - 1));
  if (tree_int_cst_lt (ar->max (), vrp_val_max (type)))
    vr1->set (VR_RANGE,
	      wide_int_to_tree (type, wi::to_wide (ar->max ()) + 1),
	      vrp_val_max (type));
  if (vr0->undefined_p ())
    {
      *vr0 = *vr1;
      vr1->set_undefined ();
    }

  return !vr0->undefined_p ();
}

/* Extract the components of a value range into a pair of wide ints in
   [WMIN, WMAX].

   If the value range is anything but a VR_*RANGE of constants, the
   resulting wide ints are set to [-MIN, +MAX] for the type.  */

static void inline
extract_range_into_wide_ints (const value_range_base *vr,
			      signop sign, unsigned prec,
			      wide_int &wmin, wide_int &wmax)
{
  gcc_assert (vr->kind () != VR_ANTI_RANGE || vr->symbolic_p ());
  if (range_int_cst_p (vr))
    {
      wmin = wi::to_wide (vr->min ());
      wmax = wi::to_wide (vr->max ());
    }
  else
    {
      wmin = wi::min_value (prec, sign);
      wmax = wi::max_value (prec, sign);
    }
}

/* Value range wrapper for wide_int_range_multiplicative_op:

     *VR = *VR0 .CODE. *VR1.  */

static void
extract_range_from_multiplicative_op (value_range_base *vr,
				      enum tree_code code,
				      const value_range_base *vr0,
				      const value_range_base *vr1)
{
  gcc_assert (code == MULT_EXPR
	      || code == TRUNC_DIV_EXPR
	      || code == FLOOR_DIV_EXPR
	      || code == CEIL_DIV_EXPR
	      || code == EXACT_DIV_EXPR
	      || code == ROUND_DIV_EXPR
	      || code == RSHIFT_EXPR
	      || code == LSHIFT_EXPR);
  gcc_assert (vr0->kind () == VR_RANGE
	      && vr0->kind () == vr1->kind ());

  tree type = vr0->type ();
  wide_int res_lb, res_ub;
  wide_int vr0_lb = wi::to_wide (vr0->min ());
  wide_int vr0_ub = wi::to_wide (vr0->max ());
  wide_int vr1_lb = wi::to_wide (vr1->min ());
  wide_int vr1_ub = wi::to_wide (vr1->max ());
  bool overflow_undefined = TYPE_OVERFLOW_UNDEFINED (type);
  unsigned prec = TYPE_PRECISION (type);

  if (wide_int_range_multiplicative_op (res_lb, res_ub,
					code, TYPE_SIGN (type), prec,
					vr0_lb, vr0_ub, vr1_lb, vr1_ub,
					overflow_undefined))
    vr->set_and_canonicalize (VR_RANGE,
			      wide_int_to_tree (type, res_lb),
			      wide_int_to_tree (type, res_ub));
  else
    vr->set_varying ();
}

/* If BOUND will include a symbolic bound, adjust it accordingly,
   otherwise leave it as is.

   CODE is the original operation that combined the bounds (PLUS_EXPR
   or MINUS_EXPR).

   TYPE is the type of the original operation.

   SYM_OPn is the symbolic for OPn if it has a symbolic.

   NEG_OPn is TRUE if the OPn was negated.  */

static void
adjust_symbolic_bound (tree &bound, enum tree_code code, tree type,
		       tree sym_op0, tree sym_op1,
		       bool neg_op0, bool neg_op1)
{
  bool minus_p = (code == MINUS_EXPR);
  /* If the result bound is constant, we're done; otherwise, build the
     symbolic lower bound.  */
  if (sym_op0 == sym_op1)
    ;
  else if (sym_op0)
    bound = build_symbolic_expr (type, sym_op0,
				 neg_op0, bound);
  else if (sym_op1)
    {
      /* We may not negate if that might introduce
	 undefined overflow.  */
      if (!minus_p
	  || neg_op1
	  || TYPE_OVERFLOW_WRAPS (type))
	bound = build_symbolic_expr (type, sym_op1,
				     neg_op1 ^ minus_p, bound);
      else
	bound = NULL_TREE;
    }
}

/* Combine OP1 and OP1, which are two parts of a bound, into one wide
   int bound according to CODE.  CODE is the operation combining the
   bound (either a PLUS_EXPR or a MINUS_EXPR).

   TYPE is the type of the combine operation.

   WI is the wide int to store the result.

   OVF is -1 if an underflow occurred, +1 if an overflow occurred or 0
   if over/underflow occurred.  */

static void
combine_bound (enum tree_code code, wide_int &wi, wi::overflow_type &ovf,
	       tree type, tree op0, tree op1)
{
  bool minus_p = (code == MINUS_EXPR);
  const signop sgn = TYPE_SIGN (type);
  const unsigned int prec = TYPE_PRECISION (type);

  /* Combine the bounds, if any.  */
  if (op0 && op1)
    {
      if (minus_p)
	wi = wi::sub (wi::to_wide (op0), wi::to_wide (op1), sgn, &ovf);
      else
	wi = wi::add (wi::to_wide (op0), wi::to_wide (op1), sgn, &ovf);
    }
  else if (op0)
    wi = wi::to_wide (op0);
  else if (op1)
    {
      if (minus_p)
	wi = wi::neg (wi::to_wide (op1), &ovf);
      else
	wi = wi::to_wide (op1);
    }
  else
    wi = wi::shwi (0, prec);
}

/* Given a range in [WMIN, WMAX], adjust it for possible overflow and
   put the result in VR.

   TYPE is the type of the range.

   MIN_OVF and MAX_OVF indicate what type of overflow, if any,
   occurred while originally calculating WMIN or WMAX.  -1 indicates
   underflow.  +1 indicates overflow.  0 indicates neither.  */

static void
set_value_range_with_overflow (value_range_kind &kind, tree &min, tree &max,
			       tree type,
			       const wide_int &wmin, const wide_int &wmax,
			       wi::overflow_type min_ovf,
			       wi::overflow_type max_ovf)
{
  const signop sgn = TYPE_SIGN (type);
  const unsigned int prec = TYPE_PRECISION (type);

  /* For one bit precision if max < min, then the swapped
     range covers all values.  */
  if (prec == 1 && wi::lt_p (wmax, wmin, sgn))
    {
      kind = VR_VARYING;
      return;
    }

  if (TYPE_OVERFLOW_WRAPS (type))
    {
      /* If overflow wraps, truncate the values and adjust the
	 range kind and bounds appropriately.  */
      wide_int tmin = wide_int::from (wmin, prec, sgn);
      wide_int tmax = wide_int::from (wmax, prec, sgn);
      if ((min_ovf != wi::OVF_NONE) == (max_ovf != wi::OVF_NONE))
	{
	  /* If the limits are swapped, we wrapped around and cover
	     the entire range.  We have a similar check at the end of
	     extract_range_from_binary_expr.  */
	  if (wi::gt_p (tmin, tmax, sgn))
	    kind = VR_VARYING;
	  else
	    {
	      kind = VR_RANGE;
	      /* No overflow or both overflow or underflow.  The
		 range kind stays VR_RANGE.  */
	      min = wide_int_to_tree (type, tmin);
	      max = wide_int_to_tree (type, tmax);
	    }
	  return;
	}
      else if ((min_ovf == wi::OVF_UNDERFLOW && max_ovf == wi::OVF_NONE)
	       || (max_ovf == wi::OVF_OVERFLOW && min_ovf == wi::OVF_NONE))
	{
	  /* Min underflow or max overflow.  The range kind
	     changes to VR_ANTI_RANGE.  */
	  bool covers = false;
	  wide_int tem = tmin;
	  tmin = tmax + 1;
	  if (wi::cmp (tmin, tmax, sgn) < 0)
	    covers = true;
	  tmax = tem - 1;
	  if (wi::cmp (tmax, tem, sgn) > 0)
	    covers = true;
	  /* If the anti-range would cover nothing, drop to varying.
	     Likewise if the anti-range bounds are outside of the
	     types values.  */
	  if (covers || wi::cmp (tmin, tmax, sgn) > 0)
	    {
	      kind = VR_VARYING;
	      return;
	    }
	  kind = VR_ANTI_RANGE;
	  min = wide_int_to_tree (type, tmin);
	  max = wide_int_to_tree (type, tmax);
	  return;
	}
      else
	{
	  /* Other underflow and/or overflow, drop to VR_VARYING.  */
	  kind = VR_VARYING;
	  return;
	}
    }
  else
    {
      /* If overflow does not wrap, saturate to the types min/max
	 value.  */
      wide_int type_min = wi::min_value (prec, sgn);
      wide_int type_max = wi::max_value (prec, sgn);
      kind = VR_RANGE;
      if (min_ovf == wi::OVF_UNDERFLOW)
	min = wide_int_to_tree (type, type_min);
      else if (min_ovf == wi::OVF_OVERFLOW)
	min = wide_int_to_tree (type, type_max);
      else
	min = wide_int_to_tree (type, wmin);

      if (max_ovf == wi::OVF_UNDERFLOW)
	max = wide_int_to_tree (type, type_min);
      else if (max_ovf == wi::OVF_OVERFLOW)
	max = wide_int_to_tree (type, type_max);
      else
	max = wide_int_to_tree (type, wmax);
    }
}

/* Extract range information from a binary operation CODE based on
   the ranges of each of its operands *VR0 and *VR1 with resulting
   type EXPR_TYPE.  The resulting range is stored in *VR.  */

void
extract_range_from_binary_expr (value_range_base *vr,
				enum tree_code code, tree expr_type,
				const value_range_base *vr0_,
				const value_range_base *vr1_)
{
  signop sign = TYPE_SIGN (expr_type);
  unsigned int prec = TYPE_PRECISION (expr_type);
  value_range_base vr0 = *vr0_, vr1 = *vr1_;
  value_range_base vrtem0, vrtem1;
  enum value_range_kind type;
  tree min = NULL_TREE, max = NULL_TREE;
  int cmp;

  if (!INTEGRAL_TYPE_P (expr_type)
      && !POINTER_TYPE_P (expr_type))
    {
      vr->set_varying ();
      return;
    }

  /* Not all binary expressions can be applied to ranges in a
     meaningful way.  Handle only arithmetic operations.  */
  if (code != PLUS_EXPR
      && code != MINUS_EXPR
      && code != POINTER_PLUS_EXPR
      && code != MULT_EXPR
      && code != TRUNC_DIV_EXPR
      && code != FLOOR_DIV_EXPR
      && code != CEIL_DIV_EXPR
      && code != EXACT_DIV_EXPR
      && code != ROUND_DIV_EXPR
      && code != TRUNC_MOD_EXPR
      && code != RSHIFT_EXPR
      && code != LSHIFT_EXPR
      && code != MIN_EXPR
      && code != MAX_EXPR
      && code != BIT_AND_EXPR
      && code != BIT_IOR_EXPR
      && code != BIT_XOR_EXPR)
    {
      vr->set_varying ();
      return;
    }

  /* If both ranges are UNDEFINED, so is the result.  */
  if (vr0.undefined_p () && vr1.undefined_p ())
    {
      vr->set_undefined ();
      return;
    }
  /* If one of the ranges is UNDEFINED drop it to VARYING for the following
     code.  At some point we may want to special-case operations that
     have UNDEFINED result for all or some value-ranges of the not UNDEFINED
     operand.  */
  else if (vr0.undefined_p ())
    vr0.set_varying ();
  else if (vr1.undefined_p ())
    vr1.set_varying ();

  /* We get imprecise results from ranges_from_anti_range when
     code is EXACT_DIV_EXPR.  We could mask out bits in the resulting
     range, but then we also need to hack up vrp_union.  It's just
     easier to special case when vr0 is ~[0,0] for EXACT_DIV_EXPR.  */
  if (code == EXACT_DIV_EXPR && range_is_nonnull (&vr0))
    {
      vr->set_nonnull (expr_type);
      return;
    }

  /* Now canonicalize anti-ranges to ranges when they are not symbolic
     and express ~[] op X as ([]' op X) U ([]'' op X).  */
  if (vr0.kind () == VR_ANTI_RANGE
      && ranges_from_anti_range (&vr0, &vrtem0, &vrtem1))
    {
      extract_range_from_binary_expr (vr, code, expr_type, &vrtem0, vr1_);
      if (!vrtem1.undefined_p ())
	{
	  value_range_base vrres;
	  extract_range_from_binary_expr (&vrres, code, expr_type,
					  &vrtem1, vr1_);
	  vr->union_ (&vrres);
	}
      return;
    }
  /* Likewise for X op ~[].  */
  if (vr1.kind () == VR_ANTI_RANGE
      && ranges_from_anti_range (&vr1, &vrtem0, &vrtem1))
    {
      extract_range_from_binary_expr (vr, code, expr_type, vr0_, &vrtem0);
      if (!vrtem1.undefined_p ())
	{
	  value_range_base vrres;
	  extract_range_from_binary_expr (&vrres, code, expr_type,
					  vr0_, &vrtem1);
	  vr->union_ (&vrres);
	}
      return;
    }

  /* The type of the resulting value range defaults to VR0.TYPE.  */
  type = vr0.kind ();

  /* Refuse to operate on VARYING ranges, ranges of different kinds
     and symbolic ranges.  As an exception, we allow BIT_{AND,IOR}
     because we may be able to derive a useful range even if one of
     the operands is VR_VARYING or symbolic range.  Similarly for
     divisions, MIN/MAX and PLUS/MINUS.

     TODO, we may be able to derive anti-ranges in some cases.  */
  if (code != BIT_AND_EXPR
      && code != BIT_IOR_EXPR
      && code != TRUNC_DIV_EXPR
      && code != FLOOR_DIV_EXPR
      && code != CEIL_DIV_EXPR
      && code != EXACT_DIV_EXPR
      && code != ROUND_DIV_EXPR
      && code != TRUNC_MOD_EXPR
      && code != MIN_EXPR
      && code != MAX_EXPR
      && code != PLUS_EXPR
      && code != MINUS_EXPR
      && code != RSHIFT_EXPR
      && code != POINTER_PLUS_EXPR
      && (vr0.varying_p ()
	  || vr1.varying_p ()
	  || vr0.kind () != vr1.kind ()
	  || vr0.symbolic_p ()
	  || vr1.symbolic_p ()))
    {
      vr->set_varying ();
      return;
    }

  /* Now evaluate the expression to determine the new range.  */
  if (POINTER_TYPE_P (expr_type))
    {
      if (code == MIN_EXPR || code == MAX_EXPR)
	{
	  /* For MIN/MAX expressions with pointers, we only care about
	     nullness, if both are non null, then the result is nonnull.
	     If both are null, then the result is null. Otherwise they
	     are varying.  */
	  if (!range_includes_zero_p (&vr0) && !range_includes_zero_p (&vr1))
	    vr->set_nonnull (expr_type);
	  else if (range_is_null (&vr0) && range_is_null (&vr1))
	    vr->set_null (expr_type);
	  else
	    vr->set_varying ();
	}
      else if (code == POINTER_PLUS_EXPR)
	{
	  /* For pointer types, we are really only interested in asserting
	     whether the expression evaluates to non-NULL.
	     With -fno-delete-null-pointer-checks we need to be more
	     conservative.  As some object might reside at address 0,
	     then some offset could be added to it and the same offset
	     subtracted again and the result would be NULL.
	     E.g.
	     static int a[12]; where &a[0] is NULL and
	     ptr = &a[6];
	     ptr -= 6;
	     ptr will be NULL here, even when there is POINTER_PLUS_EXPR
	     where the first range doesn't include zero and the second one
	     doesn't either.  As the second operand is sizetype (unsigned),
	     consider all ranges where the MSB could be set as possible
	     subtractions where the result might be NULL.  */
	  if ((!range_includes_zero_p (&vr0)
	       || !range_includes_zero_p (&vr1))
	      && !TYPE_OVERFLOW_WRAPS (expr_type)
	      && (flag_delete_null_pointer_checks
		  || (range_int_cst_p (&vr1)
		      && !tree_int_cst_sign_bit (vr1.max ()))))
	    vr->set_nonnull (expr_type);
	  else if (range_is_null (&vr0) && range_is_null (&vr1))
	    vr->set_null (expr_type);
	  else
	    vr->set_varying ();
	}
      else if (code == BIT_AND_EXPR)
	{
	  /* For pointer types, we are really only interested in asserting
	     whether the expression evaluates to non-NULL.  */
	  if (range_is_null (&vr0) || range_is_null (&vr1))
	    vr->set_null (expr_type);
	  else
	    vr->set_varying ();
	}
      else
	vr->set_varying ();

      return;
    }

  /* For integer ranges, apply the operation to each end of the
     range and see what we end up with.  */
  if (code == PLUS_EXPR || code == MINUS_EXPR)
    {
      /* This will normalize things such that calculating
	 [0,0] - VR_VARYING is not dropped to varying, but is
	 calculated as [MIN+1, MAX].  */
      if (vr0.varying_p ())
	vr0.set (VR_RANGE, vrp_val_min (expr_type), vrp_val_max (expr_type));
      if (vr1.varying_p ())
	vr1.set (VR_RANGE, vrp_val_min (expr_type), vrp_val_max (expr_type));

      const bool minus_p = (code == MINUS_EXPR);
      tree min_op0 = vr0.min ();
      tree min_op1 = minus_p ? vr1.max () : vr1.min ();
      tree max_op0 = vr0.max ();
      tree max_op1 = minus_p ? vr1.min () : vr1.max ();
      tree sym_min_op0 = NULL_TREE;
      tree sym_min_op1 = NULL_TREE;
      tree sym_max_op0 = NULL_TREE;
      tree sym_max_op1 = NULL_TREE;
      bool neg_min_op0, neg_min_op1, neg_max_op0, neg_max_op1;

      neg_min_op0 = neg_min_op1 = neg_max_op0 = neg_max_op1 = false;

      /* If we have a PLUS or MINUS with two VR_RANGEs, either constant or
	 single-symbolic ranges, try to compute the precise resulting range,
	 but only if we know that this resulting range will also be constant
	 or single-symbolic.  */
      if (vr0.kind () == VR_RANGE && vr1.kind () == VR_RANGE
	  && (TREE_CODE (min_op0) == INTEGER_CST
	      || (sym_min_op0
		  = get_single_symbol (min_op0, &neg_min_op0, &min_op0)))
	  && (TREE_CODE (min_op1) == INTEGER_CST
	      || (sym_min_op1
		  = get_single_symbol (min_op1, &neg_min_op1, &min_op1)))
	  && (!(sym_min_op0 && sym_min_op1)
	      || (sym_min_op0 == sym_min_op1
		  && neg_min_op0 == (minus_p ? neg_min_op1 : !neg_min_op1)))
	  && (TREE_CODE (max_op0) == INTEGER_CST
	      || (sym_max_op0
		  = get_single_symbol (max_op0, &neg_max_op0, &max_op0)))
	  && (TREE_CODE (max_op1) == INTEGER_CST
	      || (sym_max_op1
		  = get_single_symbol (max_op1, &neg_max_op1, &max_op1)))
	  && (!(sym_max_op0 && sym_max_op1)
	      || (sym_max_op0 == sym_max_op1
		  && neg_max_op0 == (minus_p ? neg_max_op1 : !neg_max_op1))))
	{
	  wide_int wmin, wmax;
	  wi::overflow_type min_ovf = wi::OVF_NONE;
	  wi::overflow_type max_ovf = wi::OVF_NONE;

	  /* Build the bounds.  */
	  combine_bound (code, wmin, min_ovf, expr_type, min_op0, min_op1);
	  combine_bound (code, wmax, max_ovf, expr_type, max_op0, max_op1);

	  /* If the resulting range will be symbolic, we need to eliminate any
	     explicit or implicit overflow introduced in the above computation
	     because compare_values could make an incorrect use of it.  That's
	     why we require one of the ranges to be a singleton.  */
	  if ((sym_min_op0 != sym_min_op1 || sym_max_op0 != sym_max_op1)
	      && ((bool)min_ovf || (bool)max_ovf
		  || (min_op0 != max_op0 && min_op1 != max_op1)))
	    {
	      vr->set_varying ();
	      return;
	    }

	  /* Adjust the range for possible overflow.  */
	  set_value_range_with_overflow (type, min, max, expr_type,
					 wmin, wmax, min_ovf, max_ovf);
	  if (type == VR_VARYING)
	    {
	      vr->set_varying ();
	      return;
	    }

	  /* Build the symbolic bounds if needed.  */
	  adjust_symbolic_bound (min, code, expr_type,
				 sym_min_op0, sym_min_op1,
				 neg_min_op0, neg_min_op1);
	  adjust_symbolic_bound (max, code, expr_type,
				 sym_max_op0, sym_max_op1,
				 neg_max_op0, neg_max_op1);
	}
      else
	{
	  /* For other cases, for example if we have a PLUS_EXPR with two
	     VR_ANTI_RANGEs, drop to VR_VARYING.  It would take more effort
	     to compute a precise range for such a case.
	     ???  General even mixed range kind operations can be expressed
	     by for example transforming ~[3, 5] + [1, 2] to range-only
	     operations and a union primitive:
	       [-INF, 2] + [1, 2]  U  [5, +INF] + [1, 2]
	           [-INF+1, 4]     U    [6, +INF(OVF)]
	     though usually the union is not exactly representable with
	     a single range or anti-range as the above is
		 [-INF+1, +INF(OVF)] intersected with ~[5, 5]
	     but one could use a scheme similar to equivalences for this. */
	  vr->set_varying ();
	  return;
	}
    }
  else if (code == MIN_EXPR
	   || code == MAX_EXPR)
    {
      wide_int wmin, wmax;
      wide_int vr0_min, vr0_max;
      wide_int vr1_min, vr1_max;
      extract_range_into_wide_ints (&vr0, sign, prec, vr0_min, vr0_max);
      extract_range_into_wide_ints (&vr1, sign, prec, vr1_min, vr1_max);
      if (wide_int_range_min_max (wmin, wmax, code, sign, prec,
				  vr0_min, vr0_max, vr1_min, vr1_max))
	vr->set (VR_RANGE, wide_int_to_tree (expr_type, wmin),
		 wide_int_to_tree (expr_type, wmax));
      else
	vr->set_varying ();
      return;
    }
  else if (code == MULT_EXPR)
    {
      if (!range_int_cst_p (&vr0)
	  || !range_int_cst_p (&vr1))
	{
	  vr->set_varying ();
	  return;
	}
      extract_range_from_multiplicative_op (vr, code, &vr0, &vr1);
      return;
    }
  else if (code == RSHIFT_EXPR
	   || code == LSHIFT_EXPR)
    {
      if (range_int_cst_p (&vr1)
	  && !wide_int_range_shift_undefined_p
		(TYPE_SIGN (TREE_TYPE (vr1.min ())),
		 prec,
		 wi::to_wide (vr1.min ()),
		 wi::to_wide (vr1.max ())))
	{
	  if (code == RSHIFT_EXPR)
	    {
	      /* Even if vr0 is VARYING or otherwise not usable, we can derive
		 useful ranges just from the shift count.  E.g.
		 x >> 63 for signed 64-bit x is always [-1, 0].  */
	      if (vr0.kind () != VR_RANGE || vr0.symbolic_p ())
		vr0.set (VR_RANGE, vrp_val_min (expr_type),
			 vrp_val_max (expr_type));
	      extract_range_from_multiplicative_op (vr, code, &vr0, &vr1);
	      return;
	    }
	  else if (code == LSHIFT_EXPR
		   && range_int_cst_p (&vr0))
	    {
	      wide_int res_lb, res_ub;
	      if (wide_int_range_lshift (res_lb, res_ub, sign, prec,
					 wi::to_wide (vr0.min ()),
					 wi::to_wide (vr0.max ()),
					 wi::to_wide (vr1.min ()),
					 wi::to_wide (vr1.max ()),
					 TYPE_OVERFLOW_UNDEFINED (expr_type)))
		{
		  min = wide_int_to_tree (expr_type, res_lb);
		  max = wide_int_to_tree (expr_type, res_ub);
		  vr->set_and_canonicalize (VR_RANGE, min, max);
		  return;
		}
	    }
	}
      vr->set_varying ();
      return;
    }
  else if (code == TRUNC_DIV_EXPR
	   || code == FLOOR_DIV_EXPR
	   || code == CEIL_DIV_EXPR
	   || code == EXACT_DIV_EXPR
	   || code == ROUND_DIV_EXPR)
    {
      wide_int dividend_min, dividend_max, divisor_min, divisor_max;
      wide_int wmin, wmax, extra_min, extra_max;
      bool extra_range_p;

      /* Special case explicit division by zero as undefined.  */
      if (range_is_null (&vr1))
	{
	  vr->set_undefined ();
	  return;
	}

      /* First, normalize ranges into constants we can handle.  Note
	 that VR_ANTI_RANGE's of constants were already normalized
	 before arriving here.

	 NOTE: As a future improvement, we may be able to do better
	 with mixed symbolic (anti-)ranges like [0, A].  See note in
	 ranges_from_anti_range.  */
      extract_range_into_wide_ints (&vr0, sign, prec,
				    dividend_min, dividend_max);
      extract_range_into_wide_ints (&vr1, sign, prec,
				    divisor_min, divisor_max);
      if (!wide_int_range_div (wmin, wmax, code, sign, prec,
			       dividend_min, dividend_max,
			       divisor_min, divisor_max,
			       TYPE_OVERFLOW_UNDEFINED (expr_type),
			       extra_range_p, extra_min, extra_max))
	{
	  vr->set_varying ();
	  return;
	}
      vr->set (VR_RANGE, wide_int_to_tree (expr_type, wmin),
	       wide_int_to_tree (expr_type, wmax));
      if (extra_range_p)
	{
	  value_range_base
	    extra_range (VR_RANGE, wide_int_to_tree (expr_type, extra_min),
			 wide_int_to_tree (expr_type, extra_max));
	  vr->union_ (&extra_range);
	}
      return;
    }
  else if (code == TRUNC_MOD_EXPR)
    {
      if (range_is_null (&vr1))
	{
	  vr->set_undefined ();
	  return;
	}
      wide_int wmin, wmax, tmp;
      wide_int vr0_min, vr0_max, vr1_min, vr1_max;
      extract_range_into_wide_ints (&vr0, sign, prec, vr0_min, vr0_max);
      extract_range_into_wide_ints (&vr1, sign, prec, vr1_min, vr1_max);
      wide_int_range_trunc_mod (wmin, wmax, sign, prec,
				vr0_min, vr0_max, vr1_min, vr1_max);
      min = wide_int_to_tree (expr_type, wmin);
      max = wide_int_to_tree (expr_type, wmax);
      vr->set (VR_RANGE, min, max);
      return;
    }
  else if (code == BIT_AND_EXPR || code == BIT_IOR_EXPR || code == BIT_XOR_EXPR)
    {
      wide_int may_be_nonzero0, may_be_nonzero1;
      wide_int must_be_nonzero0, must_be_nonzero1;
      wide_int wmin, wmax;
      wide_int vr0_min, vr0_max, vr1_min, vr1_max;
      vrp_set_zero_nonzero_bits (expr_type, &vr0,
				 &may_be_nonzero0, &must_be_nonzero0);
      vrp_set_zero_nonzero_bits (expr_type, &vr1,
				 &may_be_nonzero1, &must_be_nonzero1);
      extract_range_into_wide_ints (&vr0, sign, prec, vr0_min, vr0_max);
      extract_range_into_wide_ints (&vr1, sign, prec, vr1_min, vr1_max);
      if (code == BIT_AND_EXPR)
	{
	  if (wide_int_range_bit_and (wmin, wmax, sign, prec,
				      vr0_min, vr0_max,
				      vr1_min, vr1_max,
				      must_be_nonzero0,
				      may_be_nonzero0,
				      must_be_nonzero1,
				      may_be_nonzero1))
	    {
	      min = wide_int_to_tree (expr_type, wmin);
	      max = wide_int_to_tree (expr_type, wmax);
	      vr->set (VR_RANGE, min, max);
	    }
	  else
	    vr->set_varying ();
	  return;
	}
      else if (code == BIT_IOR_EXPR)
	{
	  if (wide_int_range_bit_ior (wmin, wmax, sign,
				      vr0_min, vr0_max,
				      vr1_min, vr1_max,
				      must_be_nonzero0,
				      may_be_nonzero0,
				      must_be_nonzero1,
				      may_be_nonzero1))
	    {
	      min = wide_int_to_tree (expr_type, wmin);
	      max = wide_int_to_tree (expr_type, wmax);
	      vr->set (VR_RANGE, min, max);
	    }
	  else
	    vr->set_varying ();
	  return;
	}
      else if (code == BIT_XOR_EXPR)
	{
	  if (wide_int_range_bit_xor (wmin, wmax, sign, prec,
				      must_be_nonzero0,
				      may_be_nonzero0,
				      must_be_nonzero1,
				      may_be_nonzero1))
	    {
	      min = wide_int_to_tree (expr_type, wmin);
	      max = wide_int_to_tree (expr_type, wmax);
	      vr->set (VR_RANGE, min, max);
	    }
	  else
	    vr->set_varying ();
	  return;
	}
    }
  else
    gcc_unreachable ();

  /* If either MIN or MAX overflowed, then set the resulting range to
     VARYING.  */
  if (min == NULL_TREE
      || TREE_OVERFLOW_P (min)
      || max == NULL_TREE
      || TREE_OVERFLOW_P (max))
    {
      vr->set_varying ();
      return;
    }

  /* We punt for [-INF, +INF].
     We learn nothing when we have INF on both sides.
     Note that we do accept [-INF, -INF] and [+INF, +INF].  */
  if (vrp_val_is_min (min) && vrp_val_is_max (max))
    {
      vr->set_varying ();
      return;
    }

  cmp = compare_values (min, max);
  if (cmp == -2 || cmp == 1)
    {
      /* If the new range has its limits swapped around (MIN > MAX),
	 then the operation caused one of them to wrap around, mark
	 the new range VARYING.  */
      vr->set_varying ();
    }
  else
    vr->set (type, min, max);
}

/* Extract range information from a unary operation CODE based on
   the range of its operand *VR0 with type OP0_TYPE with resulting type TYPE.
   The resulting range is stored in *VR.  */

void
extract_range_from_unary_expr (value_range_base *vr,
			       enum tree_code code, tree type,
			       const value_range_base *vr0_, tree op0_type)
{
  signop sign = TYPE_SIGN (type);
  unsigned int prec = TYPE_PRECISION (type);
  value_range_base vr0 = *vr0_;
  value_range_base vrtem0, vrtem1;

  /* VRP only operates on integral and pointer types.  */
  if (!(INTEGRAL_TYPE_P (op0_type)
	|| POINTER_TYPE_P (op0_type))
      || !(INTEGRAL_TYPE_P (type)
	   || POINTER_TYPE_P (type)))
    {
      vr->set_varying ();
      return;
    }

  /* If VR0 is UNDEFINED, so is the result.  */
  if (vr0.undefined_p ())
    {
      vr->set_undefined ();
      return;
    }

  /* Handle operations that we express in terms of others.  */
  if (code == PAREN_EXPR)
    {
      /* PAREN_EXPR and OBJ_TYPE_REF are simple copies.  */
      *vr = vr0;
      return;
    }
  else if (code == NEGATE_EXPR)
    {
      /* -X is simply 0 - X, so re-use existing code that also handles
         anti-ranges fine.  */
      value_range_base zero;
      zero.set (build_int_cst (type, 0));
      extract_range_from_binary_expr (vr, MINUS_EXPR, type, &zero, &vr0);
      return;
    }
  else if (code == BIT_NOT_EXPR)
    {
      /* ~X is simply -1 - X, so re-use existing code that also handles
         anti-ranges fine.  */
      value_range_base minusone;
      minusone.set (build_int_cst (type, -1));
      extract_range_from_binary_expr (vr, MINUS_EXPR, type, &minusone, &vr0);
      return;
    }

  /* Now canonicalize anti-ranges to ranges when they are not symbolic
     and express op ~[]  as (op []') U (op []'').  */
  if (vr0.kind () == VR_ANTI_RANGE
      && ranges_from_anti_range (&vr0, &vrtem0, &vrtem1))
    {
      extract_range_from_unary_expr (vr, code, type, &vrtem0, op0_type);
      if (!vrtem1.undefined_p ())
	{
	  value_range_base vrres;
	  extract_range_from_unary_expr (&vrres, code, type,
					 &vrtem1, op0_type);
	  vr->union_ (&vrres);
	}
      return;
    }

  if (CONVERT_EXPR_CODE_P (code))
    {
      tree inner_type = op0_type;
      tree outer_type = type;

      /* If the expression involves a pointer, we are only interested in
	 determining if it evaluates to NULL [0, 0] or non-NULL (~[0, 0]).

	 This may lose precision when converting (char *)~[0,2] to
	 int, because we'll forget that the pointer can also not be 1
	 or 2.  In practice we don't care, as this is some idiot
	 storing a magic constant to a pointer.  */
      if (POINTER_TYPE_P (type) || POINTER_TYPE_P (op0_type))
	{
	  if (!range_includes_zero_p (&vr0))
	    vr->set_nonnull (type);
	  else if (range_is_null (&vr0))
	    vr->set_null (type);
	  else
	    vr->set_varying ();
	  return;
	}

      /* The POINTER_TYPE_P code above will have dealt with all
	 pointer anti-ranges.  Any remaining anti-ranges at this point
	 will be integer conversions from SSA names that will be
	 normalized into VARYING.  For instance: ~[x_55, x_55].  */
      gcc_assert (vr0.kind () != VR_ANTI_RANGE
		  || TREE_CODE (vr0.min ()) != INTEGER_CST);

      /* NOTES: Previously we were returning VARYING for all symbolics, but
	 we can do better by treating them as [-MIN, +MAX].  For
	 example, converting [SYM, SYM] from INT to LONG UNSIGNED,
	 we can return: ~[0x8000000, 0xffffffff7fffffff].

	 We were also failing to convert ~[0,0] from char* to unsigned,
	 instead choosing to return VR_VARYING.  Now we return ~[0,0].  */
      wide_int vr0_min, vr0_max, wmin, wmax;
      signop inner_sign = TYPE_SIGN (inner_type);
      signop outer_sign = TYPE_SIGN (outer_type);
      unsigned inner_prec = TYPE_PRECISION (inner_type);
      unsigned outer_prec = TYPE_PRECISION (outer_type);
      extract_range_into_wide_ints (&vr0, inner_sign, inner_prec,
				    vr0_min, vr0_max);
      if (wide_int_range_convert (wmin, wmax,
				  inner_sign, inner_prec,
				  outer_sign, outer_prec,
				  vr0_min, vr0_max))
	{
	  tree min = wide_int_to_tree (outer_type, wmin);
	  tree max = wide_int_to_tree (outer_type, wmax);
	  vr->set_and_canonicalize (VR_RANGE, min, max);
	}
      else
	vr->set_varying ();
      return;
    }
  else if (code == ABS_EXPR)
    {
      wide_int wmin, wmax;
      wide_int vr0_min, vr0_max;
      extract_range_into_wide_ints (&vr0, sign, prec, vr0_min, vr0_max);
      if (wide_int_range_abs (wmin, wmax, sign, prec, vr0_min, vr0_max,
			      TYPE_OVERFLOW_UNDEFINED (type)))
	vr->set (VR_RANGE, wide_int_to_tree (type, wmin),
		 wide_int_to_tree (type, wmax));
      else
	vr->set_varying ();
      return;
    }
  else if (code == ABSU_EXPR)
    {
      wide_int wmin, wmax;
      wide_int vr0_min, vr0_max;
      extract_range_into_wide_ints (&vr0, SIGNED, prec, vr0_min, vr0_max);
      wide_int_range_absu (wmin, wmax, prec, vr0_min, vr0_max);
      vr->set (VR_RANGE, wide_int_to_tree (type, wmin),
	       wide_int_to_tree (type, wmax));
      return;
    }

  /* For unhandled operations fall back to varying.  */
  vr->set_varying ();
  return;
}

/* Given a COND_EXPR COND of the form 'V OP W', and an SSA name V,
   create a new SSA name N and return the assertion assignment
   'N = ASSERT_EXPR <V, V OP W>'.  */

static gimple *
build_assert_expr_for (tree cond, tree v)
{
  tree a;
  gassign *assertion;

  gcc_assert (TREE_CODE (v) == SSA_NAME
	      && COMPARISON_CLASS_P (cond));

  a = build2 (ASSERT_EXPR, TREE_TYPE (v), v, cond);
  assertion = gimple_build_assign (NULL_TREE, a);

  /* The new ASSERT_EXPR, creates a new SSA name that replaces the
     operand of the ASSERT_EXPR.  Create it so the new name and the old one
     are registered in the replacement table so that we can fix the SSA web
     after adding all the ASSERT_EXPRs.  */
  tree new_def = create_new_def_for (v, assertion, NULL);
  /* Make sure we preserve abnormalness throughout an ASSERT_EXPR chain
     given we have to be able to fully propagate those out to re-create
     valid SSA when removing the asserts.  */
  if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (v))
    SSA_NAME_OCCURS_IN_ABNORMAL_PHI (new_def) = 1;

  return assertion;
}


/* Return false if EXPR is a predicate expression involving floating
   point values.  */

static inline bool
fp_predicate (gimple *stmt)
{
  GIMPLE_CHECK (stmt, GIMPLE_COND);

  return FLOAT_TYPE_P (TREE_TYPE (gimple_cond_lhs (stmt)));
}

/* If the range of values taken by OP can be inferred after STMT executes,
   return the comparison code (COMP_CODE_P) and value (VAL_P) that
   describes the inferred range.  Return true if a range could be
   inferred.  */

bool
infer_value_range (gimple *stmt, tree op, tree_code *comp_code_p, tree *val_p)
{
  *val_p = NULL_TREE;
  *comp_code_p = ERROR_MARK;

  /* Do not attempt to infer anything in names that flow through
     abnormal edges.  */
  if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
    return false;

  /* If STMT is the last statement of a basic block with no normal
     successors, there is no point inferring anything about any of its
     operands.  We would not be able to find a proper insertion point
     for the assertion, anyway.  */
  if (stmt_ends_bb_p (stmt))
    {
      edge_iterator ei;
      edge e;

      FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
	if (!(e->flags & (EDGE_ABNORMAL|EDGE_EH)))
	  break;
      if (e == NULL)
	return false;
    }

  if (infer_nonnull_range (stmt, op))
    {
      *val_p = build_int_cst (TREE_TYPE (op), 0);
      *comp_code_p = NE_EXPR;
      return true;
    }

  return false;
}


void dump_asserts_for (FILE *, tree);
void debug_asserts_for (tree);
void dump_all_asserts (FILE *);
void debug_all_asserts (void);

/* Dump all the registered assertions for NAME to FILE.  */

void
dump_asserts_for (FILE *file, tree name)
{
  assert_locus *loc;

  fprintf (file, "Assertions to be inserted for ");
  print_generic_expr (file, name);
  fprintf (file, "\n");

  loc = asserts_for[SSA_NAME_VERSION (name)];
  while (loc)
    {
      fprintf (file, "\t");
      print_gimple_stmt (file, gsi_stmt (loc->si), 0);
      fprintf (file, "\n\tBB #%d", loc->bb->index);
      if (loc->e)
	{
	  fprintf (file, "\n\tEDGE %d->%d", loc->e->src->index,
	           loc->e->dest->index);
	  dump_edge_info (file, loc->e, dump_flags, 0);
	}
      fprintf (file, "\n\tPREDICATE: ");
      print_generic_expr (file, loc->expr);
      fprintf (file, " %s ", get_tree_code_name (loc->comp_code));
      print_generic_expr (file, loc->val);
      fprintf (file, "\n\n");
      loc = loc->next;
    }

  fprintf (file, "\n");
}


/* Dump all the registered assertions for NAME to stderr.  */

DEBUG_FUNCTION void
debug_asserts_for (tree name)
{
  dump_asserts_for (stderr, name);
}


/* Dump all the registered assertions for all the names to FILE.  */

void
dump_all_asserts (FILE *file)
{
  unsigned i;
  bitmap_iterator bi;

  fprintf (file, "\nASSERT_EXPRs to be inserted\n\n");
  EXECUTE_IF_SET_IN_BITMAP (need_assert_for, 0, i, bi)
    dump_asserts_for (file, ssa_name (i));
  fprintf (file, "\n");
}


/* Dump all the registered assertions for all the names to stderr.  */

DEBUG_FUNCTION void
debug_all_asserts (void)
{
  dump_all_asserts (stderr);
}

/* Push the assert info for NAME, EXPR, COMP_CODE and VAL to ASSERTS.  */

static void
add_assert_info (vec<assert_info> &asserts,
		 tree name, tree expr, enum tree_code comp_code, tree val)
{
  assert_info info;
  info.comp_code = comp_code;
  info.name = name;
  if (TREE_OVERFLOW_P (val))
    val = drop_tree_overflow (val);
  info.val = val;
  info.expr = expr;
  asserts.safe_push (info);
  if (dump_enabled_p ())
    dump_printf (MSG_NOTE | MSG_PRIORITY_INTERNALS,
		 "Adding assert for %T from %T %s %T\n",
		 name, expr, op_symbol_code (comp_code), val);
}

/* If NAME doesn't have an ASSERT_EXPR registered for asserting
   'EXPR COMP_CODE VAL' at a location that dominates block BB or
   E->DEST, then register this location as a possible insertion point
   for ASSERT_EXPR <NAME, EXPR COMP_CODE VAL>.

   BB, E and SI provide the exact insertion point for the new
   ASSERT_EXPR.  If BB is NULL, then the ASSERT_EXPR is to be inserted
   on edge E.  Otherwise, if E is NULL, the ASSERT_EXPR is inserted on
   BB.  If SI points to a COND_EXPR or a SWITCH_EXPR statement, then E
   must not be NULL.  */

static void
register_new_assert_for (tree name, tree expr,
			 enum tree_code comp_code,
			 tree val,
			 basic_block bb,
			 edge e,
			 gimple_stmt_iterator si)
{
  assert_locus *n, *loc, *last_loc;
  basic_block dest_bb;

  gcc_checking_assert (bb == NULL || e == NULL);

  if (e == NULL)
    gcc_checking_assert (gimple_code (gsi_stmt (si)) != GIMPLE_COND
			 && gimple_code (gsi_stmt (si)) != GIMPLE_SWITCH);

  /* Never build an assert comparing against an integer constant with
     TREE_OVERFLOW set.  This confuses our undefined overflow warning
     machinery.  */
  if (TREE_OVERFLOW_P (val))
    val = drop_tree_overflow (val);

  /* The new assertion A will be inserted at BB or E.  We need to
     determine if the new location is dominated by a previously
     registered location for A.  If we are doing an edge insertion,
     assume that A will be inserted at E->DEST.  Note that this is not
     necessarily true.

     If E is a critical edge, it will be split.  But even if E is
     split, the new block will dominate the same set of blocks that
     E->DEST dominates.

     The reverse, however, is not true, blocks dominated by E->DEST
     will not be dominated by the new block created to split E.  So,
     if the insertion location is on a critical edge, we will not use
     the new location to move another assertion previously registered
     at a block dominated by E->DEST.  */
  dest_bb = (bb) ? bb : e->dest;

  /* If NAME already has an ASSERT_EXPR registered for COMP_CODE and
     VAL at a block dominating DEST_BB, then we don't need to insert a new
     one.  Similarly, if the same assertion already exists at a block
     dominated by DEST_BB and the new location is not on a critical
     edge, then update the existing location for the assertion (i.e.,
     move the assertion up in the dominance tree).

     Note, this is implemented as a simple linked list because there
     should not be more than a handful of assertions registered per
     name.  If this becomes a performance problem, a table hashed by
     COMP_CODE and VAL could be implemented.  */
  loc = asserts_for[SSA_NAME_VERSION (name)];
  last_loc = loc;
  while (loc)
    {
      if (loc->comp_code == comp_code
	  && (loc->val == val
	      || operand_equal_p (loc->val, val, 0))
	  && (loc->expr == expr
	      || operand_equal_p (loc->expr, expr, 0)))
	{
	  /* If E is not a critical edge and DEST_BB
	     dominates the existing location for the assertion, move
	     the assertion up in the dominance tree by updating its
	     location information.  */
	  if ((e == NULL || !EDGE_CRITICAL_P (e))
	      && dominated_by_p (CDI_DOMINATORS, loc->bb, dest_bb))
	    {
	      loc->bb = dest_bb;
	      loc->e = e;
	      loc->si = si;
	      return;
	    }
	}

      /* Update the last node of the list and move to the next one.  */
      last_loc = loc;
      loc = loc->next;
    }

  /* If we didn't find an assertion already registered for
     NAME COMP_CODE VAL, add a new one at the end of the list of
     assertions associated with NAME.  */
  n = XNEW (struct assert_locus);
  n->bb = dest_bb;
  n->e = e;
  n->si = si;
  n->comp_code = comp_code;
  n->val = val;
  n->expr = expr;
  n->next = NULL;

  if (last_loc)
    last_loc->next = n;
  else
    asserts_for[SSA_NAME_VERSION (name)] = n;

  bitmap_set_bit (need_assert_for, SSA_NAME_VERSION (name));
}

/* (COND_OP0 COND_CODE COND_OP1) is a predicate which uses NAME.
   Extract a suitable test code and value and store them into *CODE_P and
   *VAL_P so the predicate is normalized to NAME *CODE_P *VAL_P.

   If no extraction was possible, return FALSE, otherwise return TRUE.

   If INVERT is true, then we invert the result stored into *CODE_P.  */

static bool
extract_code_and_val_from_cond_with_ops (tree name, enum tree_code cond_code,
					 tree cond_op0, tree cond_op1,
					 bool invert, enum tree_code *code_p,
					 tree *val_p)
{
  enum tree_code comp_code;
  tree val;

  /* Otherwise, we have a comparison of the form NAME COMP VAL
     or VAL COMP NAME.  */
  if (name == cond_op1)
    {
      /* If the predicate is of the form VAL COMP NAME, flip
	 COMP around because we need to register NAME as the
	 first operand in the predicate.  */
      comp_code = swap_tree_comparison (cond_code);
      val = cond_op0;
    }
  else if (name == cond_op0)
    {
      /* The comparison is of the form NAME COMP VAL, so the
	 comparison code remains unchanged.  */
      comp_code = cond_code;
      val = cond_op1;
    }
  else
    gcc_unreachable ();

  /* Invert the comparison code as necessary.  */
  if (invert)
    comp_code = invert_tree_comparison (comp_code, 0);

  /* VRP only handles integral and pointer types.  */
  if (! INTEGRAL_TYPE_P (TREE_TYPE (val))
      && ! POINTER_TYPE_P (TREE_TYPE (val)))
    return false;

  /* Do not register always-false predicates.
     FIXME:  this works around a limitation in fold() when dealing with
     enumerations.  Given 'enum { N1, N2 } x;', fold will not
     fold 'if (x > N2)' to 'if (0)'.  */
  if ((comp_code == GT_EXPR || comp_code == LT_EXPR)
      && INTEGRAL_TYPE_P (TREE_TYPE (val)))
    {
      tree min = TYPE_MIN_VALUE (TREE_TYPE (val));
      tree max = TYPE_MAX_VALUE (TREE_TYPE (val));

      if (comp_code == GT_EXPR
	  && (!max
	      || compare_values (val, max) == 0))
	return false;

      if (comp_code == LT_EXPR
	  && (!min
	      || compare_values (val, min) == 0))
	return false;
    }
  *code_p = comp_code;
  *val_p = val;
  return true;
}

/* Find out smallest RES where RES > VAL && (RES & MASK) == RES, if any
   (otherwise return VAL).  VAL and MASK must be zero-extended for
   precision PREC.  If SGNBIT is non-zero, first xor VAL with SGNBIT
   (to transform signed values into unsigned) and at the end xor
   SGNBIT back.  */

static wide_int
masked_increment (const wide_int &val_in, const wide_int &mask,
		  const wide_int &sgnbit, unsigned int prec)
{
  wide_int bit = wi::one (prec), res;
  unsigned int i;

  wide_int val = val_in ^ sgnbit;
  for (i = 0; i < prec; i++, bit += bit)
    {
      res = mask;
      if ((res & bit) == 0)
	continue;
      res = bit - 1;
      res = wi::bit_and_not (val + bit, res);
      res &= mask;
      if (wi::gtu_p (res, val))
	return res ^ sgnbit;
    }
  return val ^ sgnbit;
}

/* Helper for overflow_comparison_p

   OP0 CODE OP1 is a comparison.  Examine the comparison and potentially
   OP1's defining statement to see if it ultimately has the form
   OP0 CODE (OP0 PLUS INTEGER_CST)

   If so, return TRUE indicating this is an overflow test and store into
   *NEW_CST an updated constant that can be used in a narrowed range test.

   REVERSED indicates if the comparison was originally:

   OP1 CODE' OP0.

   This affects how we build the updated constant.  */

static bool
overflow_comparison_p_1 (enum tree_code code, tree op0, tree op1,
		         bool follow_assert_exprs, bool reversed, tree *new_cst)
{
  /* See if this is a relational operation between two SSA_NAMES with
     unsigned, overflow wrapping values.  If so, check it more deeply.  */
  if ((code == LT_EXPR || code == LE_EXPR
       || code == GE_EXPR || code == GT_EXPR)
      && TREE_CODE (op0) == SSA_NAME
      && TREE_CODE (op1) == SSA_NAME
      && INTEGRAL_TYPE_P (TREE_TYPE (op0))
      && TYPE_UNSIGNED (TREE_TYPE (op0))
      && TYPE_OVERFLOW_WRAPS (TREE_TYPE (op0)))
    {
      gimple *op1_def = SSA_NAME_DEF_STMT (op1);

      /* If requested, follow any ASSERT_EXPRs backwards for OP1.  */
      if (follow_assert_exprs)
	{
	  while (gimple_assign_single_p (op1_def)
		 && TREE_CODE (gimple_assign_rhs1 (op1_def)) == ASSERT_EXPR)
	    {
	      op1 = TREE_OPERAND (gimple_assign_rhs1 (op1_def), 0);
	      if (TREE_CODE (op1) != SSA_NAME)
		break;
	      op1_def = SSA_NAME_DEF_STMT (op1);
	    }
	}

      /* Now look at the defining statement of OP1 to see if it adds
	 or subtracts a nonzero constant from another operand.  */
      if (op1_def
	  && is_gimple_assign (op1_def)
	  && gimple_assign_rhs_code (op1_def) == PLUS_EXPR
	  && TREE_CODE (gimple_assign_rhs2 (op1_def)) == INTEGER_CST
	  && !integer_zerop (gimple_assign_rhs2 (op1_def)))
	{
	  tree target = gimple_assign_rhs1 (op1_def);

	  /* If requested, follow ASSERT_EXPRs backwards for op0 looking
	     for one where TARGET appears on the RHS.  */
	  if (follow_assert_exprs)
	    {
	      /* Now see if that "other operand" is op0, following the chain
		 of ASSERT_EXPRs if necessary.  */
	      gimple *op0_def = SSA_NAME_DEF_STMT (op0);
	      while (op0 != target
		     && gimple_assign_single_p (op0_def)
		     && TREE_CODE (gimple_assign_rhs1 (op0_def)) == ASSERT_EXPR)
		{
		  op0 = TREE_OPERAND (gimple_assign_rhs1 (op0_def), 0);
		  if (TREE_CODE (op0) != SSA_NAME)
		    break;
		  op0_def = SSA_NAME_DEF_STMT (op0);
		}
	    }

	  /* If we did not find our target SSA_NAME, then this is not
	     an overflow test.  */
	  if (op0 != target)
	    return false;

	  tree type = TREE_TYPE (op0);
	  wide_int max = wi::max_value (TYPE_PRECISION (type), UNSIGNED);
	  tree inc = gimple_assign_rhs2 (op1_def);
	  if (reversed)
	    *new_cst = wide_int_to_tree (type, max + wi::to_wide (inc));
	  else
	    *new_cst = wide_int_to_tree (type, max - wi::to_wide (inc));
	  return true;
	}
    }
  return false;
}

/* OP0 CODE OP1 is a comparison.  Examine the comparison and potentially
   OP1's defining statement to see if it ultimately has the form
   OP0 CODE (OP0 PLUS INTEGER_CST)

   If so, return TRUE indicating this is an overflow test and store into
   *NEW_CST an updated constant that can be used in a narrowed range test.

   These statements are left as-is in the IL to facilitate discovery of
   {ADD,SUB}_OVERFLOW sequences later in the optimizer pipeline.  But
   the alternate range representation is often useful within VRP.  */

bool
overflow_comparison_p (tree_code code, tree name, tree val,
		       bool use_equiv_p, tree *new_cst)
{
  if (overflow_comparison_p_1 (code, name, val, use_equiv_p, false, new_cst))
    return true;
  return overflow_comparison_p_1 (swap_tree_comparison (code), val, name,
				  use_equiv_p, true, new_cst);
}


/* Try to register an edge assertion for SSA name NAME on edge E for
   the condition COND contributing to the conditional jump pointed to by BSI.
   Invert the condition COND if INVERT is true.  */

static void
register_edge_assert_for_2 (tree name, edge e,
			    enum tree_code cond_code,
			    tree cond_op0, tree cond_op1, bool invert,
			    vec<assert_info> &asserts)
{
  tree val;
  enum tree_code comp_code;

  if (!extract_code_and_val_from_cond_with_ops (name, cond_code,
						cond_op0,
						cond_op1,
						invert, &comp_code, &val))
    return;

  /* Queue the assert.  */
  tree x;
  if (overflow_comparison_p (comp_code, name, val, false, &x))
    {
      enum tree_code new_code = ((comp_code == GT_EXPR || comp_code == GE_EXPR)
				 ? GT_EXPR : LE_EXPR);
      add_assert_info (asserts, name, name, new_code, x);
    }
  add_assert_info (asserts, name, name, comp_code, val);

  /* In the case of NAME <= CST and NAME being defined as
     NAME = (unsigned) NAME2 + CST2 we can assert NAME2 >= -CST2
     and NAME2 <= CST - CST2.  We can do the same for NAME > CST.
     This catches range and anti-range tests.  */
  if ((comp_code == LE_EXPR
       || comp_code == GT_EXPR)
      && TREE_CODE (val) == INTEGER_CST
      && TYPE_UNSIGNED (TREE_TYPE (val)))
    {
      gimple *def_stmt = SSA_NAME_DEF_STMT (name);
      tree cst2 = NULL_TREE, name2 = NULL_TREE, name3 = NULL_TREE;

      /* Extract CST2 from the (optional) addition.  */
      if (is_gimple_assign (def_stmt)
	  && gimple_assign_rhs_code (def_stmt) == PLUS_EXPR)
	{
	  name2 = gimple_assign_rhs1 (def_stmt);
	  cst2 = gimple_assign_rhs2 (def_stmt);
	  if (TREE_CODE (name2) == SSA_NAME
	      && TREE_CODE (cst2) == INTEGER_CST)
	    def_stmt = SSA_NAME_DEF_STMT (name2);
	}

      /* Extract NAME2 from the (optional) sign-changing cast.  */
      if (gimple_assign_cast_p (def_stmt))
	{
	  if (CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt))
	      && ! TYPE_UNSIGNED (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
	      && (TYPE_PRECISION (gimple_expr_type (def_stmt))
		  == TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))))
	    name3 = gimple_assign_rhs1 (def_stmt);
	}

      /* If name3 is used later, create an ASSERT_EXPR for it.  */
      if (name3 != NULL_TREE
      	  && TREE_CODE (name3) == SSA_NAME
	  && (cst2 == NULL_TREE
	      || TREE_CODE (cst2) == INTEGER_CST)
	  && INTEGRAL_TYPE_P (TREE_TYPE (name3)))
	{
	  tree tmp;

	  /* Build an expression for the range test.  */
	  tmp = build1 (NOP_EXPR, TREE_TYPE (name), name3);
	  if (cst2 != NULL_TREE)
	    tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
	  add_assert_info (asserts, name3, tmp, comp_code, val);
	}

      /* If name2 is used later, create an ASSERT_EXPR for it.  */
      if (name2 != NULL_TREE
      	  && TREE_CODE (name2) == SSA_NAME
	  && TREE_CODE (cst2) == INTEGER_CST
	  && INTEGRAL_TYPE_P (TREE_TYPE (name2)))
	{
	  tree tmp;

	  /* Build an expression for the range test.  */
	  tmp = name2;
	  if (TREE_TYPE (name) != TREE_TYPE (name2))
	    tmp = build1 (NOP_EXPR, TREE_TYPE (name), tmp);
	  if (cst2 != NULL_TREE)
	    tmp = build2 (PLUS_EXPR, TREE_TYPE (name), tmp, cst2);
	  add_assert_info (asserts, name2, tmp, comp_code, val);
	}
    }

  /* In the case of post-in/decrement tests like if (i++) ... and uses
     of the in/decremented value on the edge the extra name we want to
     assert for is not on the def chain of the name compared.  Instead
     it is in the set of use stmts.
     Similar cases happen for conversions that were simplified through
     fold_{sign_changed,widened}_comparison.  */
  if ((comp_code == NE_EXPR
       || comp_code == EQ_EXPR)
      && TREE_CODE (val) == INTEGER_CST)
    {
      imm_use_iterator ui;
      gimple *use_stmt;
      FOR_EACH_IMM_USE_STMT (use_stmt, ui, name)
	{
	  if (!is_gimple_assign (use_stmt))
	    continue;

	  /* Cut off to use-stmts that are dominating the predecessor.  */
	  if (!dominated_by_p (CDI_DOMINATORS, e->src, gimple_bb (use_stmt)))
	    continue;

	  tree name2 = gimple_assign_lhs (use_stmt);
	  if (TREE_CODE (name2) != SSA_NAME)
	    continue;

	  enum tree_code code = gimple_assign_rhs_code (use_stmt);
	  tree cst;
	  if (code == PLUS_EXPR
	      || code == MINUS_EXPR)
	    {
	      cst = gimple_assign_rhs2 (use_stmt);
	      if (TREE_CODE (cst) != INTEGER_CST)
		continue;
	      cst = int_const_binop (code, val, cst);
	    }
	  else if (CONVERT_EXPR_CODE_P (code))
	    {
	      /* For truncating conversions we cannot record
		 an inequality.  */
	      if (comp_code == NE_EXPR
		  && (TYPE_PRECISION (TREE_TYPE (name2))
		      < TYPE_PRECISION (TREE_TYPE (name))))
		continue;
	      cst = fold_convert (TREE_TYPE (name2), val);
	    }
	  else
	    continue;

	  if (TREE_OVERFLOW_P (cst))
	    cst = drop_tree_overflow (cst);
	  add_assert_info (asserts, name2, name2, comp_code, cst);
	}
    }
 
  if (TREE_CODE_CLASS (comp_code) == tcc_comparison
      && TREE_CODE (val) == INTEGER_CST)
    {
      gimple *def_stmt = SSA_NAME_DEF_STMT (name);
      tree name2 = NULL_TREE, names[2], cst2 = NULL_TREE;
      tree val2 = NULL_TREE;
      unsigned int prec = TYPE_PRECISION (TREE_TYPE (val));
      wide_int mask = wi::zero (prec);
      unsigned int nprec = prec;
      enum tree_code rhs_code = ERROR_MARK;

      if (is_gimple_assign (def_stmt))
	rhs_code = gimple_assign_rhs_code (def_stmt);

      /* In the case of NAME != CST1 where NAME = A +- CST2 we can
         assert that A != CST1 -+ CST2.  */
      if ((comp_code == EQ_EXPR || comp_code == NE_EXPR)
	  && (rhs_code == PLUS_EXPR || rhs_code == MINUS_EXPR))
	{
	  tree op0 = gimple_assign_rhs1 (def_stmt);
	  tree op1 = gimple_assign_rhs2 (def_stmt);
	  if (TREE_CODE (op0) == SSA_NAME
	      && TREE_CODE (op1) == INTEGER_CST)
	    {
	      enum tree_code reverse_op = (rhs_code == PLUS_EXPR
					   ? MINUS_EXPR : PLUS_EXPR);
	      op1 = int_const_binop (reverse_op, val, op1);
	      if (TREE_OVERFLOW (op1))
		op1 = drop_tree_overflow (op1);
	      add_assert_info (asserts, op0, op0, comp_code, op1);
	    }
	}

      /* Add asserts for NAME cmp CST and NAME being defined
	 as NAME = (int) NAME2.  */
      if (!TYPE_UNSIGNED (TREE_TYPE (val))
	  && (comp_code == LE_EXPR || comp_code == LT_EXPR
	      || comp_code == GT_EXPR || comp_code == GE_EXPR)
	  && gimple_assign_cast_p (def_stmt))
	{
	  name2 = gimple_assign_rhs1 (def_stmt);
	  if (CONVERT_EXPR_CODE_P (rhs_code)
	      && TREE_CODE (name2) == SSA_NAME
	      && INTEGRAL_TYPE_P (TREE_TYPE (name2))
	      && TYPE_UNSIGNED (TREE_TYPE (name2))
	      && prec == TYPE_PRECISION (TREE_TYPE (name2))
	      && (comp_code == LE_EXPR || comp_code == GT_EXPR
		  || !tree_int_cst_equal (val,
					  TYPE_MIN_VALUE (TREE_TYPE (val)))))
	    {
	      tree tmp, cst;
	      enum tree_code new_comp_code = comp_code;

	      cst = fold_convert (TREE_TYPE (name2),
				  TYPE_MIN_VALUE (TREE_TYPE (val)));
	      /* Build an expression for the range test.  */
	      tmp = build2 (PLUS_EXPR, TREE_TYPE (name2), name2, cst);
	      cst = fold_build2 (PLUS_EXPR, TREE_TYPE (name2), cst,
				 fold_convert (TREE_TYPE (name2), val));
	      if (comp_code == LT_EXPR || comp_code == GE_EXPR)
		{
		  new_comp_code = comp_code == LT_EXPR ? LE_EXPR : GT_EXPR;
		  cst = fold_build2 (MINUS_EXPR, TREE_TYPE (name2), cst,
				     build_int_cst (TREE_TYPE (name2), 1));
		}
	      add_assert_info (asserts, name2, tmp, new_comp_code, cst);
	    }
	}

      /* Add asserts for NAME cmp CST and NAME being defined as
	 NAME = NAME2 >> CST2.

	 Extract CST2 from the right shift.  */
      if (rhs_code == RSHIFT_EXPR)
	{
	  name2 = gimple_assign_rhs1 (def_stmt);
	  cst2 = gimple_assign_rhs2 (def_stmt);
	  if (TREE_CODE (name2) == SSA_NAME
	      && tree_fits_uhwi_p (cst2)
	      && INTEGRAL_TYPE_P (TREE_TYPE (name2))
	      && IN_RANGE (tree_to_uhwi (cst2), 1, prec - 1)
	      && type_has_mode_precision_p (TREE_TYPE (val)))
	    {
	      mask = wi::mask (tree_to_uhwi (cst2), false, prec);
	      val2 = fold_binary (LSHIFT_EXPR, TREE_TYPE (val), val, cst2);
	    }
	}
      if (val2 != NULL_TREE
	  && TREE_CODE (val2) == INTEGER_CST
	  && simple_cst_equal (fold_build2 (RSHIFT_EXPR,
					    TREE_TYPE (val),
					    val2, cst2), val))
	{
	  enum tree_code new_comp_code = comp_code;
	  tree tmp, new_val;

	  tmp = name2;
	  if (comp_code == EQ_EXPR || comp_code == NE_EXPR)
	    {
	      if (!TYPE_UNSIGNED (TREE_TYPE (val)))
		{
		  tree type = build_nonstandard_integer_type (prec, 1);
		  tmp = build1 (NOP_EXPR, type, name2);
		  val2 = fold_convert (type, val2);
		}
	      tmp = fold_build2 (MINUS_EXPR, TREE_TYPE (tmp), tmp, val2);
	      new_val = wide_int_to_tree (TREE_TYPE (tmp), mask);
	      new_comp_code = comp_code == EQ_EXPR ? LE_EXPR : GT_EXPR;
	    }
	  else if (comp_code == LT_EXPR || comp_code == GE_EXPR)
	    {
	      wide_int minval
		= wi::min_value (prec, TYPE_SIGN (TREE_TYPE (val)));
	      new_val = val2;
	      if (minval == wi::to_wide (new_val))
		new_val = NULL_TREE;
	    }
	  else
	    {
	      wide_int maxval
		= wi::max_value (prec, TYPE_SIGN (TREE_TYPE (val)));
	      mask |= wi::to_wide (val2);
	      if (wi::eq_p (mask, maxval))
		new_val = NULL_TREE;
	      else
		new_val = wide_int_to_tree (TREE_TYPE (val2), mask);
	    }

	  if (new_val)
	    add_assert_info (asserts, name2, tmp, new_comp_code, new_val);
	}

      /* If we have a conversion that doesn't change the value of the source
         simply register the same assert for it.  */
      if (CONVERT_EXPR_CODE_P (rhs_code))
	{
	  wide_int rmin, rmax;
	  tree rhs1 = gimple_assign_rhs1 (def_stmt);
	  if (INTEGRAL_TYPE_P (TREE_TYPE (rhs1))
	      && TREE_CODE (rhs1) == SSA_NAME
	      /* Make sure the relation preserves the upper/lower boundary of
	         the range conservatively.  */
	      && (comp_code == NE_EXPR
		  || comp_code == EQ_EXPR
		  || (TYPE_SIGN (TREE_TYPE (name))
		      == TYPE_SIGN (TREE_TYPE (rhs1)))
		  || ((comp_code == LE_EXPR
		       || comp_code == LT_EXPR)
		      && !TYPE_UNSIGNED (TREE_TYPE (rhs1)))
		  || ((comp_code == GE_EXPR
		       || comp_code == GT_EXPR)
		      && TYPE_UNSIGNED (TREE_TYPE (rhs1))))
	      /* And the conversion does not alter the value we compare
	         against and all values in rhs1 can be represented in
		 the converted to type.  */
	      && int_fits_type_p (val, TREE_TYPE (rhs1))
	      && ((TYPE_PRECISION (TREE_TYPE (name))
		   > TYPE_PRECISION (TREE_TYPE (rhs1)))
		  || (get_range_info (rhs1, &rmin, &rmax) == VR_RANGE
		      && wi::fits_to_tree_p
			   (widest_int::from (rmin,
					      TYPE_SIGN (TREE_TYPE (rhs1))),
			    TREE_TYPE (name))
		      && wi::fits_to_tree_p
			   (widest_int::from (rmax,
					      TYPE_SIGN (TREE_TYPE (rhs1))),
			    TREE_TYPE (name)))))
	    add_assert_info (asserts, rhs1, rhs1,
		 	     comp_code, fold_convert (TREE_TYPE (rhs1), val));
	}

      /* Add asserts for NAME cmp CST and NAME being defined as
	 NAME = NAME2 & CST2.

	 Extract CST2 from the and.

	 Also handle
	 NAME = (unsigned) NAME2;
	 casts where NAME's type is unsigned and has smaller precision
	 than NAME2's type as if it was NAME = NAME2 & MASK.  */
      names[0] = NULL_TREE;
      names[1] = NULL_TREE;
      cst2 = NULL_TREE;
      if (rhs_code == BIT_AND_EXPR
	  || (CONVERT_EXPR_CODE_P (rhs_code)
	      && INTEGRAL_TYPE_P (TREE_TYPE (val))
	      && TYPE_UNSIGNED (TREE_TYPE (val))
	      && TYPE_PRECISION (TREE_TYPE (gimple_assign_rhs1 (def_stmt)))
		 > prec))
	{
	  name2 = gimple_assign_rhs1 (def_stmt);
	  if (rhs_code == BIT_AND_EXPR)
	    cst2 = gimple_assign_rhs2 (def_stmt);
	  else
	    {
	      cst2 = TYPE_MAX_VALUE (TREE_TYPE (val));
	      nprec = TYPE_PRECISION (TREE_TYPE (name2));
	    }
	  if (TREE_CODE (name2) == SSA_NAME
	      && INTEGRAL_TYPE_P (TREE_TYPE (name2))
	      && TREE_CODE (cst2) == INTEGER_CST
	      && !integer_zerop (cst2)
	      && (nprec > 1
		  || TYPE_UNSIGNED (TREE_TYPE (val))))
	    {
	      gimple *def_stmt2 = SSA_NAME_DEF_STMT (name2);
	      if (gimple_assign_cast_p (def_stmt2))
		{
		  names[1] = gimple_assign_rhs1 (def_stmt2);
		  if (!CONVERT_EXPR_CODE_P (gimple_assign_rhs_code (def_stmt2))
		      || TREE_CODE (names[1]) != SSA_NAME
		      || !INTEGRAL_TYPE_P (TREE_TYPE (names[1]))
		      || (TYPE_PRECISION (TREE_TYPE (name2))
			  != TYPE_PRECISION (TREE_TYPE (names[1]))))
		    names[1] = NULL_TREE;
		}
	      names[0] = name2;
	    }
	}
      if (names[0] || names[1])
	{
	  wide_int minv, maxv, valv, cst2v;
	  wide_int tem, sgnbit;
	  bool valid_p = false, valn, cst2n;
	  enum tree_code ccode = comp_code;

	  valv = wide_int::from (wi::to_wide (val), nprec, UNSIGNED);
	  cst2v = wide_int::from (wi::to_wide (cst2), nprec, UNSIGNED);
	  valn = wi::neg_p (valv, TYPE_SIGN (TREE_TYPE (val)));
	  cst2n = wi::neg_p (cst2v, TYPE_SIGN (TREE_TYPE (val)));
	  /* If CST2 doesn't have most significant bit set,
	     but VAL is negative, we have comparison like
	     if ((x & 0x123) > -4) (always true).  Just give up.  */
	  if (!cst2n && valn)
	    ccode = ERROR_MARK;
	  if (cst2n)
	    sgnbit = wi::set_bit_in_zero (nprec - 1, nprec);
	  else
	    sgnbit = wi::zero (nprec);
	  minv = valv & cst2v;
	  switch (ccode)
	    {
	    case EQ_EXPR:
	      /* Minimum unsigned value for equality is VAL & CST2
		 (should be equal to VAL, otherwise we probably should
		 have folded the comparison into false) and
		 maximum unsigned value is VAL | ~CST2.  */
	      maxv = valv | ~cst2v;
	      valid_p = true;
	      break;

	    case NE_EXPR:
	      tem = valv | ~cst2v;
	      /* If VAL is 0, handle (X & CST2) != 0 as (X & CST2) > 0U.  */
	      if (valv == 0)
		{
		  cst2n = false;
		  sgnbit = wi::zero (nprec);
		  goto gt_expr;
		}
	      /* If (VAL | ~CST2) is all ones, handle it as
		 (X & CST2) < VAL.  */
	      if (tem == -1)
		{
		  cst2n = false;
		  valn = false;
		  sgnbit = wi::zero (nprec);
		  goto lt_expr;
		}
	      if (!cst2n && wi::neg_p (cst2v))
		sgnbit = wi::set_bit_in_zero (nprec - 1, nprec);
	      if (sgnbit != 0)
		{
		  if (valv == sgnbit)
		    {
		      cst2n = true;
		      valn = true;
		      goto gt_expr;
		    }
		  if (tem == wi::mask (nprec - 1, false, nprec))
		    {
		      cst2n = true;
		      goto lt_expr;
		    }
		  if (!cst2n)
		    sgnbit = wi::zero (nprec);
		}
	      break;

	    case GE_EXPR:
	      /* Minimum unsigned value for >= if (VAL & CST2) == VAL
		 is VAL and maximum unsigned value is ~0.  For signed
		 comparison, if CST2 doesn't have most significant bit
		 set, handle it similarly.  If CST2 has MSB set,
		 the minimum is the same, and maximum is ~0U/2.  */
	      if (minv != valv)
		{
		  /* If (VAL & CST2) != VAL, X & CST2 can't be equal to
		     VAL.  */
		  minv = masked_increment (valv, cst2v, sgnbit, nprec);
		  if (minv == valv)
		    break;
		}
	      maxv = wi::mask (nprec - (cst2n ? 1 : 0), false, nprec);
	      valid_p = true;
	      break;

	    case GT_EXPR:
	    gt_expr:
	      /* Find out smallest MINV where MINV > VAL
		 && (MINV & CST2) == MINV, if any.  If VAL is signed and
		 CST2 has MSB set, compute it biased by 1 << (nprec - 1).  */
	      minv = masked_increment (valv, cst2v, sgnbit, nprec);
	      if (minv == valv)
		break;
	      maxv = wi::mask (nprec - (cst2n ? 1 : 0), false, nprec);
	      valid_p = true;
	      break;

	    case LE_EXPR:
	      /* Minimum unsigned value for <= is 0 and maximum
		 unsigned value is VAL | ~CST2 if (VAL & CST2) == VAL.
		 Otherwise, find smallest VAL2 where VAL2 > VAL
		 && (VAL2 & CST2) == VAL2 and use (VAL2 - 1) | ~CST2
		 as maximum.
		 For signed comp