gcc/gimple-fold.c

/* Statement simplification on GIMPLE.
   Copyright (C) 2010-2015 Free Software Foundation, Inc.
   Split out from tree-ssa-ccp.c.

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 "tm.h"
#include "hash-set.h"
#include "machmode.h"
#include "vec.h"
#include "double-int.h"
#include "input.h"
#include "alias.h"
#include "symtab.h"
#include "wide-int.h"
#include "inchash.h"
#include "tree.h"
#include "fold-const.h"
#include "stringpool.h"
#include "hashtab.h"
#include "hard-reg-set.h"
#include "function.h"
#include "rtl.h"
#include "flags.h"
#include "statistics.h"
#include "real.h"
#include "fixed-value.h"
#include "insn-config.h"
#include "expmed.h"
#include "dojump.h"
#include "explow.h"
#include "calls.h"
#include "emit-rtl.h"
#include "varasm.h"
#include "stmt.h"
#include "expr.h"
#include "stor-layout.h"
#include "dumpfile.h"
#include "bitmap.h"
#include "predict.h"
#include "dominance.h"
#include "basic-block.h"
#include "tree-ssa-alias.h"
#include "internal-fn.h"
#include "gimple-fold.h"
#include "gimple-expr.h"
#include "is-a.h"
#include "gimple.h"
#include "gimplify.h"
#include "gimple-iterator.h"
#include "gimple-ssa.h"
#include "tree-ssanames.h"
#include "tree-into-ssa.h"
#include "tree-dfa.h"
#include "tree-ssa.h"
#include "tree-ssa-propagate.h"
#include "target.h"
#include "hash-map.h"
#include "plugin-api.h"
#include "ipa-ref.h"
#include "cgraph.h"
#include "ipa-utils.h"
#include "gimple-pretty-print.h"
#include "tree-ssa-address.h"
#include "langhooks.h"
#include "gimplify-me.h"
#include "dbgcnt.h"
#include "builtins.h"
#include "output.h"
#include "tree-eh.h"
#include "gimple-match.h"
#include "tree-phinodes.h"
#include "ssa-iterators.h"
#include "ipa-chkp.h"

/* Return true when DECL can be referenced from current unit.
   FROM_DECL (if non-null) specify constructor of variable DECL was taken from.
   We can get declarations that are not possible to reference for various
   reasons:

     1) When analyzing C++ virtual tables.
	C++ virtual tables do have known constructors even
	when they are keyed to other compilation unit.
	Those tables can contain pointers to methods and vars
	in other units.  Those methods have both STATIC and EXTERNAL
	set.
     2) In WHOPR mode devirtualization might lead to reference
	to method that was partitioned elsehwere.
	In this case we have static VAR_DECL or FUNCTION_DECL
	that has no corresponding callgraph/varpool node
	declaring the body.  
     3) COMDAT functions referred by external vtables that
        we devirtualize only during final compilation stage.
        At this time we already decided that we will not output
        the function body and thus we can't reference the symbol
        directly.  */

static bool
can_refer_decl_in_current_unit_p (tree decl, tree from_decl)
{
  varpool_node *vnode;
  struct cgraph_node *node;
  symtab_node *snode;

  if (DECL_ABSTRACT_P (decl))
    return false;

  /* We are concerned only about static/external vars and functions.  */
  if ((!TREE_STATIC (decl) && !DECL_EXTERNAL (decl))
      || (TREE_CODE (decl) != VAR_DECL && TREE_CODE (decl) != FUNCTION_DECL))
    return true;

  /* Static objects can be referred only if they was not optimized out yet.  */
  if (!TREE_PUBLIC (decl) && !DECL_EXTERNAL (decl))
    {
      /* Before we start optimizing unreachable code we can be sure all
	 static objects are defined.  */
      if (symtab->function_flags_ready)
	return true;
      snode = symtab_node::get (decl);
      if (!snode || !snode->definition)
	return false;
      node = dyn_cast <cgraph_node *> (snode);
      return !node || !node->global.inlined_to;
    }

  /* We will later output the initializer, so we can refer to it.
     So we are concerned only when DECL comes from initializer of
     external var or var that has been optimized out.  */
  if (!from_decl
      || TREE_CODE (from_decl) != VAR_DECL
      || (!DECL_EXTERNAL (from_decl)
	  && (vnode = varpool_node::get (from_decl)) != NULL
	  && vnode->definition)
      || (flag_ltrans
	  && (vnode = varpool_node::get (from_decl)) != NULL
	  && vnode->in_other_partition))
    return true;
  /* We are folding reference from external vtable.  The vtable may reffer
     to a symbol keyed to other compilation unit.  The other compilation
     unit may be in separate DSO and the symbol may be hidden.  */
  if (DECL_VISIBILITY_SPECIFIED (decl)
      && DECL_EXTERNAL (decl)
      && DECL_VISIBILITY (decl) != VISIBILITY_DEFAULT
      && (!(snode = symtab_node::get (decl)) || !snode->in_other_partition))
    return false;
  /* When function is public, we always can introduce new reference.
     Exception are the COMDAT functions where introducing a direct
     reference imply need to include function body in the curren tunit.  */
  if (TREE_PUBLIC (decl) && !DECL_COMDAT (decl))
    return true;
  /* We have COMDAT.  We are going to check if we still have definition
     or if the definition is going to be output in other partition.
     Bypass this when gimplifying; all needed functions will be produced.

     As observed in PR20991 for already optimized out comdat virtual functions
     it may be tempting to not necessarily give up because the copy will be
     output elsewhere when corresponding vtable is output.  
     This is however not possible - ABI specify that COMDATs are output in
     units where they are used and when the other unit was compiled with LTO
     it is possible that vtable was kept public while the function itself
     was privatized. */
  if (!symtab->function_flags_ready)
    return true;

  snode = symtab_node::get (decl);
  if (!snode
      || ((!snode->definition || DECL_EXTERNAL (decl))
	  && (!snode->in_other_partition
	      || (!snode->forced_by_abi && !snode->force_output))))
    return false;
  node = dyn_cast <cgraph_node *> (snode);
  return !node || !node->global.inlined_to;
}

/* CVAL is value taken from DECL_INITIAL of variable.  Try to transform it into
   acceptable form for is_gimple_min_invariant.
   FROM_DECL (if non-NULL) specify variable whose constructor contains CVAL.  */

tree
canonicalize_constructor_val (tree cval, tree from_decl)
{
  tree orig_cval = cval;
  STRIP_NOPS (cval);
  if (TREE_CODE (cval) == POINTER_PLUS_EXPR
      && TREE_CODE (TREE_OPERAND (cval, 1)) == INTEGER_CST)
    {
      tree ptr = TREE_OPERAND (cval, 0);
      if (is_gimple_min_invariant (ptr))
	cval = build1_loc (EXPR_LOCATION (cval),
			   ADDR_EXPR, TREE_TYPE (ptr),
			   fold_build2 (MEM_REF, TREE_TYPE (TREE_TYPE (ptr)),
					ptr,
					fold_convert (ptr_type_node,
						      TREE_OPERAND (cval, 1))));
    }
  if (TREE_CODE (cval) == ADDR_EXPR)
    {
      tree base = NULL_TREE;
      if (TREE_CODE (TREE_OPERAND (cval, 0)) == COMPOUND_LITERAL_EXPR)
	{
	  base = COMPOUND_LITERAL_EXPR_DECL (TREE_OPERAND (cval, 0));
	  if (base)
	    TREE_OPERAND (cval, 0) = base;
	}
      else
	base = get_base_address (TREE_OPERAND (cval, 0));
      if (!base)
	return NULL_TREE;

      if ((TREE_CODE (base) == VAR_DECL
	   || TREE_CODE (base) == FUNCTION_DECL)
	  && !can_refer_decl_in_current_unit_p (base, from_decl))
	return NULL_TREE;
      if (TREE_CODE (base) == VAR_DECL)
	TREE_ADDRESSABLE (base) = 1;
      else if (TREE_CODE (base) == FUNCTION_DECL)
	{
	  /* Make sure we create a cgraph node for functions we'll reference.
	     They can be non-existent if the reference comes from an entry
	     of an external vtable for example.  */
	  cgraph_node::get_create (base);
	}
      /* Fixup types in global initializers.  */
      if (TREE_TYPE (TREE_TYPE (cval)) != TREE_TYPE (TREE_OPERAND (cval, 0)))
	cval = build_fold_addr_expr (TREE_OPERAND (cval, 0));

      if (!useless_type_conversion_p (TREE_TYPE (orig_cval), TREE_TYPE (cval)))
	cval = fold_convert (TREE_TYPE (orig_cval), cval);
      return cval;
    }
  if (TREE_OVERFLOW_P (cval))
    return drop_tree_overflow (cval);
  return orig_cval;
}

/* If SYM is a constant variable with known value, return the value.
   NULL_TREE is returned otherwise.  */

tree
get_symbol_constant_value (tree sym)
{
  tree val = ctor_for_folding (sym);
  if (val != error_mark_node)
    {
      if (val)
	{
	  val = canonicalize_constructor_val (unshare_expr (val), sym);
	  if (val && is_gimple_min_invariant (val))
	    return val;
	  else
	    return NULL_TREE;
	}
      /* Variables declared 'const' without an initializer
	 have zero as the initializer if they may not be
	 overridden at link or run time.  */
      if (!val
          && is_gimple_reg_type (TREE_TYPE (sym)))
	return build_zero_cst (TREE_TYPE (sym));
    }

  return NULL_TREE;
}



/* Subroutine of fold_stmt.  We perform several simplifications of the
   memory reference tree EXPR and make sure to re-gimplify them properly
   after propagation of constant addresses.  IS_LHS is true if the
   reference is supposed to be an lvalue.  */

static tree
maybe_fold_reference (tree expr, bool is_lhs)
{
  tree result;

  if ((TREE_CODE (expr) == VIEW_CONVERT_EXPR
       || TREE_CODE (expr) == REALPART_EXPR
       || TREE_CODE (expr) == IMAGPART_EXPR)
      && CONSTANT_CLASS_P (TREE_OPERAND (expr, 0)))
    return fold_unary_loc (EXPR_LOCATION (expr),
			   TREE_CODE (expr),
			   TREE_TYPE (expr),
			   TREE_OPERAND (expr, 0));
  else if (TREE_CODE (expr) == BIT_FIELD_REF
	   && CONSTANT_CLASS_P (TREE_OPERAND (expr, 0)))
    return fold_ternary_loc (EXPR_LOCATION (expr),
			     TREE_CODE (expr),
			     TREE_TYPE (expr),
			     TREE_OPERAND (expr, 0),
			     TREE_OPERAND (expr, 1),
			     TREE_OPERAND (expr, 2));

  if (!is_lhs
      && (result = fold_const_aggregate_ref (expr))
      && is_gimple_min_invariant (result))
    return result;

  return NULL_TREE;
}


/* Attempt to fold an assignment statement pointed-to by SI.  Returns a
   replacement rhs for the statement or NULL_TREE if no simplification
   could be made.  It is assumed that the operands have been previously
   folded.  */

static tree
fold_gimple_assign (gimple_stmt_iterator *si)
{
  gimple stmt = gsi_stmt (*si);
  enum tree_code subcode = gimple_assign_rhs_code (stmt);
  location_t loc = gimple_location (stmt);

  tree result = NULL_TREE;

  switch (get_gimple_rhs_class (subcode))
    {
    case GIMPLE_SINGLE_RHS:
      {
        tree rhs = gimple_assign_rhs1 (stmt);

	if (TREE_CLOBBER_P (rhs))
	  return NULL_TREE;

	if (REFERENCE_CLASS_P (rhs))
	  return maybe_fold_reference (rhs, false);

	else if (TREE_CODE (rhs) == OBJ_TYPE_REF)
	  {
	    tree val = OBJ_TYPE_REF_EXPR (rhs);
	    if (is_gimple_min_invariant (val))
	      return val;
	    else if (flag_devirtualize && virtual_method_call_p (rhs))
	      {
		bool final;
		vec <cgraph_node *>targets
		  = possible_polymorphic_call_targets (rhs, stmt, &final);
		if (final && targets.length () <= 1 && dbg_cnt (devirt))
		  {
		    if (dump_enabled_p ())
		      {
			location_t loc = gimple_location_safe (stmt);
			dump_printf_loc (MSG_OPTIMIZED_LOCATIONS, loc,
					 "resolving virtual function address "
					 "reference to function %s\n",
					 targets.length () == 1
					 ? targets[0]->name ()
					 : "NULL");
		      }
		    if (targets.length () == 1)
		      {
			val = fold_convert (TREE_TYPE (val),
					    build_fold_addr_expr_loc
					      (loc, targets[0]->decl));
			STRIP_USELESS_TYPE_CONVERSION (val);
		      }
		    else
		      /* We can not use __builtin_unreachable here because it
			 can not have address taken.  */
		      val = build_int_cst (TREE_TYPE (val), 0);
		    return val;
		  }
	      }

	  }
	else if (TREE_CODE (rhs) == ADDR_EXPR)
	  {
	    tree ref = TREE_OPERAND (rhs, 0);
	    tree tem = maybe_fold_reference (ref, true);
	    if (tem
		&& TREE_CODE (tem) == MEM_REF
		&& integer_zerop (TREE_OPERAND (tem, 1)))
	      result = fold_convert (TREE_TYPE (rhs), TREE_OPERAND (tem, 0));
	    else if (tem)
	      result = fold_convert (TREE_TYPE (rhs),
				     build_fold_addr_expr_loc (loc, tem));
	    else if (TREE_CODE (ref) == MEM_REF
		     && integer_zerop (TREE_OPERAND (ref, 1)))
	      result = fold_convert (TREE_TYPE (rhs), TREE_OPERAND (ref, 0));
	  }

	else if (TREE_CODE (rhs) == CONSTRUCTOR
		 && TREE_CODE (TREE_TYPE (rhs)) == VECTOR_TYPE
		 && (CONSTRUCTOR_NELTS (rhs)
		     == TYPE_VECTOR_SUBPARTS (TREE_TYPE (rhs))))
	  {
	    /* Fold a constant vector CONSTRUCTOR to VECTOR_CST.  */
	    unsigned i;
	    tree val;

	    FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (rhs), i, val)
	      if (TREE_CODE (val) != INTEGER_CST
		  && TREE_CODE (val) != REAL_CST
		  && TREE_CODE (val) != FIXED_CST)
		return NULL_TREE;

	    return build_vector_from_ctor (TREE_TYPE (rhs),
					   CONSTRUCTOR_ELTS (rhs));
	  }

	else if (DECL_P (rhs))
	  return get_symbol_constant_value (rhs);

        /* If we couldn't fold the RHS, hand over to the generic
           fold routines.  */
        if (result == NULL_TREE)
          result = fold (rhs);

        /* Strip away useless type conversions.  Both the NON_LVALUE_EXPR
           that may have been added by fold, and "useless" type
           conversions that might now be apparent due to propagation.  */
        STRIP_USELESS_TYPE_CONVERSION (result);

        if (result != rhs && valid_gimple_rhs_p (result))
	  return result;

	return NULL_TREE;
      }
      break;

    case GIMPLE_UNARY_RHS:
      break;

    case GIMPLE_BINARY_RHS:
      /* Try to canonicalize for boolean-typed X the comparisons
	 X == 0, X == 1, X != 0, and X != 1.  */
      if (gimple_assign_rhs_code (stmt) == EQ_EXPR
	  || gimple_assign_rhs_code (stmt) == NE_EXPR)
        {
	  tree lhs = gimple_assign_lhs (stmt);
	  tree op1 = gimple_assign_rhs1 (stmt);
	  tree op2 = gimple_assign_rhs2 (stmt);
	  tree type = TREE_TYPE (op1);

	  /* Check whether the comparison operands are of the same boolean
	     type as the result type is.
	     Check that second operand is an integer-constant with value
	     one or zero.  */
	  if (TREE_CODE (op2) == INTEGER_CST
	      && (integer_zerop (op2) || integer_onep (op2))
	      && useless_type_conversion_p (TREE_TYPE (lhs), type))
	    {
	      enum tree_code cmp_code = gimple_assign_rhs_code (stmt);
	      bool is_logical_not = false;

	      /* X == 0 and X != 1 is a logical-not.of X
	         X == 1 and X != 0 is X  */
	      if ((cmp_code == EQ_EXPR && integer_zerop (op2))
	          || (cmp_code == NE_EXPR && integer_onep (op2)))
	        is_logical_not = true;

	      if (is_logical_not == false)
	        result = op1;
	      /* Only for one-bit precision typed X the transformation
	         !X -> ~X is valied.  */
	      else if (TYPE_PRECISION (type) == 1)
		result = build1_loc (gimple_location (stmt), BIT_NOT_EXPR,
				     type, op1);
	      /* Otherwise we use !X -> X ^ 1.  */
	      else
	        result = build2_loc (gimple_location (stmt), BIT_XOR_EXPR,
				     type, op1, build_int_cst (type, 1));
	     
	    }
	}

      if (!result)
        result = fold_binary_loc (loc, subcode,
				  TREE_TYPE (gimple_assign_lhs (stmt)),
				  gimple_assign_rhs1 (stmt),
				  gimple_assign_rhs2 (stmt));

      if (result)
        {
          STRIP_USELESS_TYPE_CONVERSION (result);
          if (valid_gimple_rhs_p (result))
	    return result;
        }
      break;

    case GIMPLE_TERNARY_RHS:
      /* Try to fold a conditional expression.  */
      if (gimple_assign_rhs_code (stmt) == COND_EXPR)
	{
	  tree op0 = gimple_assign_rhs1 (stmt);
	  tree tem;
	  bool set = false;
	  location_t cond_loc = gimple_location (stmt);

	  if (COMPARISON_CLASS_P (op0))
	    {
	      fold_defer_overflow_warnings ();
	      tem = fold_binary_loc (cond_loc,
				     TREE_CODE (op0), TREE_TYPE (op0),
				     TREE_OPERAND (op0, 0),
				     TREE_OPERAND (op0, 1));
	      /* This is actually a conditional expression, not a GIMPLE
		 conditional statement, however, the valid_gimple_rhs_p
		 test still applies.  */
	      set = (tem && is_gimple_condexpr (tem)
		     && valid_gimple_rhs_p (tem));
	      fold_undefer_overflow_warnings (set, stmt, 0);
	    }
	  else if (is_gimple_min_invariant (op0))
	    {
	      tem = op0;
	      set = true;
	    }
	  else
	    return NULL_TREE;

	  if (set)
	    result = fold_build3_loc (cond_loc, COND_EXPR,
				      TREE_TYPE (gimple_assign_lhs (stmt)), tem,
				      gimple_assign_rhs2 (stmt),
				      gimple_assign_rhs3 (stmt));
	}

      if (!result)
	result = fold_ternary_loc (loc, subcode,
				   TREE_TYPE (gimple_assign_lhs (stmt)),
				   gimple_assign_rhs1 (stmt),
				   gimple_assign_rhs2 (stmt),
				   gimple_assign_rhs3 (stmt));

      if (result)
        {
          STRIP_USELESS_TYPE_CONVERSION (result);
          if (valid_gimple_rhs_p (result))
	    return result;
        }
      break;

    case GIMPLE_INVALID_RHS:
      gcc_unreachable ();
    }

  return NULL_TREE;
}

/* Attempt to fold a conditional statement. Return true if any changes were
   made. We only attempt to fold the condition expression, and do not perform
   any transformation that would require alteration of the cfg.  It is
   assumed that the operands have been previously folded.  */

static bool
fold_gimple_cond (gcond *stmt)
{
  tree result = fold_binary_loc (gimple_location (stmt),
			     gimple_cond_code (stmt),
                             boolean_type_node,
                             gimple_cond_lhs (stmt),
                             gimple_cond_rhs (stmt));

  if (result)
    {
      STRIP_USELESS_TYPE_CONVERSION (result);
      if (is_gimple_condexpr (result) && valid_gimple_rhs_p (result))
        {
          gimple_cond_set_condition_from_tree (stmt, result);
          return true;
        }
    }

  return false;
}


/* Replace a statement at *SI_P with a sequence of statements in STMTS,
   adjusting the replacement stmts location and virtual operands.
   If the statement has a lhs the last stmt in the sequence is expected
   to assign to that lhs.  */

static void
gsi_replace_with_seq_vops (gimple_stmt_iterator *si_p, gimple_seq stmts)
{
  gimple stmt = gsi_stmt (*si_p);

  if (gimple_has_location (stmt))
    annotate_all_with_location (stmts, gimple_location (stmt));

  /* First iterate over the replacement statements backward, assigning
     virtual operands to their defining statements.  */
  gimple laststore = NULL;
  for (gimple_stmt_iterator i = gsi_last (stmts);
       !gsi_end_p (i); gsi_prev (&i))
    {
      gimple new_stmt = gsi_stmt (i);
      if ((gimple_assign_single_p (new_stmt)
	   && !is_gimple_reg (gimple_assign_lhs (new_stmt)))
	  || (is_gimple_call (new_stmt)
	      && (gimple_call_flags (new_stmt)
		  & (ECF_NOVOPS | ECF_PURE | ECF_CONST | ECF_NORETURN)) == 0))
	{
	  tree vdef;
	  if (!laststore)
	    vdef = gimple_vdef (stmt);
	  else
	    vdef = make_ssa_name (gimple_vop (cfun), new_stmt);
	  gimple_set_vdef (new_stmt, vdef);
	  if (vdef && TREE_CODE (vdef) == SSA_NAME)
	    SSA_NAME_DEF_STMT (vdef) = new_stmt;
	  laststore = new_stmt;
	}
    }

  /* Second iterate over the statements forward, assigning virtual
     operands to their uses.  */
  tree reaching_vuse = gimple_vuse (stmt);
  for (gimple_stmt_iterator i = gsi_start (stmts);
       !gsi_end_p (i); gsi_next (&i))
    {
      gimple new_stmt = gsi_stmt (i);
      /* If the new statement possibly has a VUSE, update it with exact SSA
	 name we know will reach this one.  */
      if (gimple_has_mem_ops (new_stmt))
	gimple_set_vuse (new_stmt, reaching_vuse);
      gimple_set_modified (new_stmt, true);
      if (gimple_vdef (new_stmt))
	reaching_vuse = gimple_vdef (new_stmt);
    }

  /* If the new sequence does not do a store release the virtual
     definition of the original statement.  */
  if (reaching_vuse
      && reaching_vuse == gimple_vuse (stmt))
    {
      tree vdef = gimple_vdef (stmt);
      if (vdef
	  && TREE_CODE (vdef) == SSA_NAME)
	{
	  unlink_stmt_vdef (stmt);
	  release_ssa_name (vdef);
	}
    }

  /* Finally replace the original statement with the sequence.  */
  gsi_replace_with_seq (si_p, stmts, false);
}

/* Convert EXPR into a GIMPLE value suitable for substitution on the
   RHS of an assignment.  Insert the necessary statements before
   iterator *SI_P.  The statement at *SI_P, which must be a GIMPLE_CALL
   is replaced.  If the call is expected to produces a result, then it
   is replaced by an assignment of the new RHS to the result variable.
   If the result is to be ignored, then the call is replaced by a
   GIMPLE_NOP.  A proper VDEF chain is retained by making the first
   VUSE and the last VDEF of the whole sequence be the same as the replaced
   statement and using new SSA names for stores in between.  */

void
gimplify_and_update_call_from_tree (gimple_stmt_iterator *si_p, tree expr)
{
  tree lhs;
  gimple stmt, new_stmt;
  gimple_stmt_iterator i;
  gimple_seq stmts = NULL;

  stmt = gsi_stmt (*si_p);

  gcc_assert (is_gimple_call (stmt));

  push_gimplify_context (gimple_in_ssa_p (cfun));

  lhs = gimple_call_lhs (stmt);
  if (lhs == NULL_TREE)
    {
      gimplify_and_add (expr, &stmts);
      /* We can end up with folding a memcpy of an empty class assignment
	 which gets optimized away by C++ gimplification.  */
      if (gimple_seq_empty_p (stmts))
	{
	  pop_gimplify_context (NULL);
	  if (gimple_in_ssa_p (cfun))
	    {
	      unlink_stmt_vdef (stmt);
	      release_defs (stmt);
	    }
	  gsi_replace (si_p, gimple_build_nop (), false);
	  return;
	}
    }
  else
    {
      tree tmp = get_initialized_tmp_var (expr, &stmts, NULL);
      new_stmt = gimple_build_assign (lhs, tmp);
      i = gsi_last (stmts);
      gsi_insert_after_without_update (&i, new_stmt,
				       GSI_CONTINUE_LINKING);
    }

  pop_gimplify_context (NULL);

  gsi_replace_with_seq_vops (si_p, stmts);
}


/* Replace the call at *GSI with the gimple value VAL.  */

static void
replace_call_with_value (gimple_stmt_iterator *gsi, tree val)
{
  gimple stmt = gsi_stmt (*gsi);
  tree lhs = gimple_call_lhs (stmt);
  gimple repl;
  if (lhs)
    {
      if (!useless_type_conversion_p (TREE_TYPE (lhs), TREE_TYPE (val)))
	val = fold_convert (TREE_TYPE (lhs), val);
      repl = gimple_build_assign (lhs, val);
    }
  else
    repl = gimple_build_nop ();
  tree vdef = gimple_vdef (stmt);
  if (vdef && TREE_CODE (vdef) == SSA_NAME)
    {
      unlink_stmt_vdef (stmt);
      release_ssa_name (vdef);
    }
  gsi_replace (gsi, repl, false);
}

/* Replace the call at *GSI with the new call REPL and fold that
   again.  */

static void
replace_call_with_call_and_fold (gimple_stmt_iterator *gsi, gimple repl)
{
  gimple stmt = gsi_stmt (*gsi);
  gimple_call_set_lhs (repl, gimple_call_lhs (stmt));
  gimple_set_location (repl, gimple_location (stmt));
  if (gimple_vdef (stmt)
      && TREE_CODE (gimple_vdef (stmt)) == SSA_NAME)
    {
      gimple_set_vdef (repl, gimple_vdef (stmt));
      gimple_set_vuse (repl, gimple_vuse (stmt));
      SSA_NAME_DEF_STMT (gimple_vdef (repl)) = repl;
    }
  gsi_replace (gsi, repl, false);
  fold_stmt (gsi);
}

/* Return true if VAR is a VAR_DECL or a component thereof.  */

static bool
var_decl_component_p (tree var)
{
  tree inner = var;
  while (handled_component_p (inner))
    inner = TREE_OPERAND (inner, 0);
  return SSA_VAR_P (inner);
}

/* Fold function call to builtin mem{{,p}cpy,move}.  Return
   false if no simplification can be made.
   If ENDP is 0, return DEST (like memcpy).
   If ENDP is 1, return DEST+LEN (like mempcpy).
   If ENDP is 2, return DEST+LEN-1 (like stpcpy).
   If ENDP is 3, return DEST, additionally *SRC and *DEST may overlap
   (memmove).   */

static bool
gimple_fold_builtin_memory_op (gimple_stmt_iterator *gsi,
			       tree dest, tree src, int endp)
{
  gimple stmt = gsi_stmt (*gsi);
  tree lhs = gimple_call_lhs (stmt);
  tree len = gimple_call_arg (stmt, 2);
  tree destvar, srcvar;
  location_t loc = gimple_location (stmt);

  /* If the LEN parameter is zero, return DEST.  */
  if (integer_zerop (len))
    {
      gimple repl;
      if (gimple_call_lhs (stmt))
	repl = gimple_build_assign (gimple_call_lhs (stmt), dest);
      else
	repl = gimple_build_nop ();
      tree vdef = gimple_vdef (stmt);
      if (vdef && TREE_CODE (vdef) == SSA_NAME)
	{
	  unlink_stmt_vdef (stmt);
	  release_ssa_name (vdef);
	}
      gsi_replace (gsi, repl, false);
      return true;
    }

  /* If SRC and DEST are the same (and not volatile), return
     DEST{,+LEN,+LEN-1}.  */
  if (operand_equal_p (src, dest, 0))
    {
      unlink_stmt_vdef (stmt);
      if (gimple_vdef (stmt) && TREE_CODE (gimple_vdef (stmt)) == SSA_NAME)
	release_ssa_name (gimple_vdef (stmt));
      if (!lhs)
	{
	  gsi_replace (gsi, gimple_build_nop (), false);
	  return true;
	}
      goto done;
    }
  else
    {
      tree srctype, desttype;
      unsigned int src_align, dest_align;
      tree off0;

      /* Inlining of memcpy/memmove may cause bounds lost (if we copy
	 pointers as wide integer) and also may result in huge function
	 size because of inlined bounds copy.  Thus don't inline for
	 functions we want to instrument.  */
      if (flag_check_pointer_bounds
	  && chkp_instrumentable_p (cfun->decl)
	  /* Even if data may contain pointers we can inline if copy
	     less than a pointer size.  */
	  && (!tree_fits_uhwi_p (len)
	      || compare_tree_int (len, POINTER_SIZE_UNITS) >= 0))
	return false;

      /* Build accesses at offset zero with a ref-all character type.  */
      off0 = build_int_cst (build_pointer_type_for_mode (char_type_node,
							 ptr_mode, true), 0);

      /* If we can perform the copy efficiently with first doing all loads
         and then all stores inline it that way.  Currently efficiently
	 means that we can load all the memory into a single integer
	 register which is what MOVE_MAX gives us.  */
      src_align = get_pointer_alignment (src);
      dest_align = get_pointer_alignment (dest);
      if (tree_fits_uhwi_p (len)
	  && compare_tree_int (len, MOVE_MAX) <= 0
	  /* ???  Don't transform copies from strings with known length this
	     confuses the tree-ssa-strlen.c.  This doesn't handle
	     the case in gcc.dg/strlenopt-8.c which is XFAILed for that
	     reason.  */
	  && !c_strlen (src, 2))
	{
	  unsigned ilen = tree_to_uhwi (len);
	  if (exact_log2 (ilen) != -1)
	    {
	      tree type = lang_hooks.types.type_for_size (ilen * 8, 1);
	      if (type
		  && TYPE_MODE (type) != BLKmode
		  && (GET_MODE_SIZE (TYPE_MODE (type)) * BITS_PER_UNIT
		      == ilen * 8)
		  /* If the destination pointer is not aligned we must be able
		     to emit an unaligned store.  */
		  && (dest_align >= GET_MODE_ALIGNMENT (TYPE_MODE (type))
		      || !SLOW_UNALIGNED_ACCESS (TYPE_MODE (type), dest_align)))
		{
		  tree srctype = type;
		  tree desttype = type;
		  if (src_align < GET_MODE_ALIGNMENT (TYPE_MODE (type)))
		    srctype = build_aligned_type (type, src_align);
		  tree srcmem = fold_build2 (MEM_REF, srctype, src, off0);
		  tree tem = fold_const_aggregate_ref (srcmem);
		  if (tem)
		    srcmem = tem;
		  else if (src_align < GET_MODE_ALIGNMENT (TYPE_MODE (type))
			   && SLOW_UNALIGNED_ACCESS (TYPE_MODE (type),
						     src_align))
		    srcmem = NULL_TREE;
		  if (srcmem)
		    {
		      gimple new_stmt;
		      if (is_gimple_reg_type (TREE_TYPE (srcmem)))
			{
			  new_stmt = gimple_build_assign (NULL_TREE, srcmem);
			  if (gimple_in_ssa_p (cfun))
			    srcmem = make_ssa_name (TREE_TYPE (srcmem),
						    new_stmt);
			  else
			    srcmem = create_tmp_reg (TREE_TYPE (srcmem));
			  gimple_assign_set_lhs (new_stmt, srcmem);
			  gimple_set_vuse (new_stmt, gimple_vuse (stmt));
			  gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT);
			}
		      if (dest_align < GET_MODE_ALIGNMENT (TYPE_MODE (type)))
			desttype = build_aligned_type (type, dest_align);
		      new_stmt
			= gimple_build_assign (fold_build2 (MEM_REF, desttype,
							    dest, off0),
					       srcmem);
		      gimple_set_vuse (new_stmt, gimple_vuse (stmt));
		      gimple_set_vdef (new_stmt, gimple_vdef (stmt));
		      if (gimple_vdef (new_stmt)
			  && TREE_CODE (gimple_vdef (new_stmt)) == SSA_NAME)
			SSA_NAME_DEF_STMT (gimple_vdef (new_stmt)) = new_stmt;
		      if (!lhs)
			{
			  gsi_replace (gsi, new_stmt, false);
			  return true;
			}
		      gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT);
		      goto done;
		    }
		}
	    }
	}

      if (endp == 3)
	{
	  /* Both DEST and SRC must be pointer types.
	     ??? This is what old code did.  Is the testing for pointer types
	     really mandatory?

	     If either SRC is readonly or length is 1, we can use memcpy.  */
	  if (!dest_align || !src_align)
	    return false;
	  if (readonly_data_expr (src)
	      || (tree_fits_uhwi_p (len)
		  && (MIN (src_align, dest_align) / BITS_PER_UNIT
		      >= tree_to_uhwi (len))))
	    {
	      tree fn = builtin_decl_implicit (BUILT_IN_MEMCPY);
	      if (!fn)
		return false;
	      gimple_call_set_fndecl (stmt, fn);
	      gimple_call_set_arg (stmt, 0, dest);
	      gimple_call_set_arg (stmt, 1, src);
	      fold_stmt (gsi);
	      return true;
	    }

	  /* If *src and *dest can't overlap, optimize into memcpy as well.  */
	  if (TREE_CODE (src) == ADDR_EXPR
	      && TREE_CODE (dest) == ADDR_EXPR)
	    {
	      tree src_base, dest_base, fn;
	      HOST_WIDE_INT src_offset = 0, dest_offset = 0;
	      HOST_WIDE_INT maxsize;

	      srcvar = TREE_OPERAND (src, 0);
	      src_base = get_addr_base_and_unit_offset (srcvar, &src_offset);
	      if (src_base == NULL)
		src_base = srcvar;
	      destvar = TREE_OPERAND (dest, 0);
	      dest_base = get_addr_base_and_unit_offset (destvar,
							 &dest_offset);
	      if (dest_base == NULL)
		dest_base = destvar;
	      if (tree_fits_uhwi_p (len))
		maxsize = tree_to_uhwi (len);
	      else
		maxsize = -1;
	      if (SSA_VAR_P (src_base)
		  && SSA_VAR_P (dest_base))
		{
		  if (operand_equal_p (src_base, dest_base, 0)
		      && ranges_overlap_p (src_offset, maxsize,
					   dest_offset, maxsize))
		    return false;
		}
	      else if (TREE_CODE (src_base) == MEM_REF
		       && TREE_CODE (dest_base) == MEM_REF)
		{
		  if (! operand_equal_p (TREE_OPERAND (src_base, 0),
					 TREE_OPERAND (dest_base, 0), 0))
		    return false;
		  offset_int off = mem_ref_offset (src_base) + src_offset;
		  if (!wi::fits_shwi_p (off))
		    return false;
		  src_offset = off.to_shwi ();

		  off = mem_ref_offset (dest_base) + dest_offset;
		  if (!wi::fits_shwi_p (off))
		    return false;
		  dest_offset = off.to_shwi ();
		  if (ranges_overlap_p (src_offset, maxsize,
					dest_offset, maxsize))
		    return false;
		}
	      else
		return false;

	      fn = builtin_decl_implicit (BUILT_IN_MEMCPY);
	      if (!fn)
		return false;
	      gimple_call_set_fndecl (stmt, fn);
	      gimple_call_set_arg (stmt, 0, dest);
	      gimple_call_set_arg (stmt, 1, src);
	      fold_stmt (gsi);
	      return true;
	    }

	  /* If the destination and source do not alias optimize into
	     memcpy as well.  */
	  if ((is_gimple_min_invariant (dest)
	       || TREE_CODE (dest) == SSA_NAME)
	      && (is_gimple_min_invariant (src)
		  || TREE_CODE (src) == SSA_NAME))
	    {
	      ao_ref destr, srcr;
	      ao_ref_init_from_ptr_and_size (&destr, dest, len);
	      ao_ref_init_from_ptr_and_size (&srcr, src, len);
	      if (!refs_may_alias_p_1 (&destr, &srcr, false))
		{
		  tree fn;
		  fn = builtin_decl_implicit (BUILT_IN_MEMCPY);
		  if (!fn)
		    return false;
		  gimple_call_set_fndecl (stmt, fn);
		  gimple_call_set_arg (stmt, 0, dest);
		  gimple_call_set_arg (stmt, 1, src);
		  fold_stmt (gsi);
		  return true;
		}
	    }

	  return false;
	}

      if (!tree_fits_shwi_p (len))
	return false;
      /* FIXME:
         This logic lose for arguments like (type *)malloc (sizeof (type)),
         since we strip the casts of up to VOID return value from malloc.
	 Perhaps we ought to inherit type from non-VOID argument here?  */
      STRIP_NOPS (src);
      STRIP_NOPS (dest);
      if (!POINTER_TYPE_P (TREE_TYPE (src))
	  || !POINTER_TYPE_P (TREE_TYPE (dest)))
	return false;
      /* In the following try to find a type that is most natural to be
	 used for the memcpy source and destination and that allows
	 the most optimization when memcpy is turned into a plain assignment
	 using that type.  In theory we could always use a char[len] type
	 but that only gains us that the destination and source possibly
	 no longer will have their address taken.  */
      /* As we fold (void *)(p + CST) to (void *)p + CST undo this here.  */
      if (TREE_CODE (src) == POINTER_PLUS_EXPR)
	{
	  tree tem = TREE_OPERAND (src, 0);
	  STRIP_NOPS (tem);
	  if (tem != TREE_OPERAND (src, 0))
	    src = build1 (NOP_EXPR, TREE_TYPE (tem), src);
	}
      if (TREE_CODE (dest) == POINTER_PLUS_EXPR)
	{
	  tree tem = TREE_OPERAND (dest, 0);
	  STRIP_NOPS (tem);
	  if (tem != TREE_OPERAND (dest, 0))
	    dest = build1 (NOP_EXPR, TREE_TYPE (tem), dest);
	}
      srctype = TREE_TYPE (TREE_TYPE (src));
      if (TREE_CODE (srctype) == ARRAY_TYPE
	  && !tree_int_cst_equal (TYPE_SIZE_UNIT (srctype), len))
	{
	  srctype = TREE_TYPE (srctype);
	  STRIP_NOPS (src);
	  src = build1 (NOP_EXPR, build_pointer_type (srctype), src);
	}
      desttype = TREE_TYPE (TREE_TYPE (dest));
      if (TREE_CODE (desttype) == ARRAY_TYPE
	  && !tree_int_cst_equal (TYPE_SIZE_UNIT (desttype), len))
	{
	  desttype = TREE_TYPE (desttype);
	  STRIP_NOPS (dest);
	  dest = build1 (NOP_EXPR, build_pointer_type (desttype), dest);
	}
      if (TREE_ADDRESSABLE (srctype)
	  || TREE_ADDRESSABLE (desttype))
	return false;

      /* Make sure we are not copying using a floating-point mode or
         a type whose size possibly does not match its precision.  */
      if (FLOAT_MODE_P (TYPE_MODE (desttype))
	  || TREE_CODE (desttype) == BOOLEAN_TYPE
	  || TREE_CODE (desttype) == ENUMERAL_TYPE)
	desttype = bitwise_type_for_mode (TYPE_MODE (desttype));
      if (FLOAT_MODE_P (TYPE_MODE (srctype))
	  || TREE_CODE (srctype) == BOOLEAN_TYPE
	  || TREE_CODE (srctype) == ENUMERAL_TYPE)
	srctype = bitwise_type_for_mode (TYPE_MODE (srctype));
      if (!srctype)
	srctype = desttype;
      if (!desttype)
	desttype = srctype;
      if (!srctype)
	return false;

      src_align = get_pointer_alignment (src);
      dest_align = get_pointer_alignment (dest);
      if (dest_align < TYPE_ALIGN (desttype)
	  || src_align < TYPE_ALIGN (srctype))
	return false;

      destvar = dest;
      STRIP_NOPS (destvar);
      if (TREE_CODE (destvar) == ADDR_EXPR
	  && var_decl_component_p (TREE_OPERAND (destvar, 0))
	  && tree_int_cst_equal (TYPE_SIZE_UNIT (desttype), len))
	destvar = fold_build2 (MEM_REF, desttype, destvar, off0);
      else
	destvar = NULL_TREE;

      srcvar = src;
      STRIP_NOPS (srcvar);
      if (TREE_CODE (srcvar) == ADDR_EXPR
	  && var_decl_component_p (TREE_OPERAND (srcvar, 0))
	  && tree_int_cst_equal (TYPE_SIZE_UNIT (srctype), len))
	{
	  if (!destvar
	      || src_align >= TYPE_ALIGN (desttype))
	    srcvar = fold_build2 (MEM_REF, destvar ? desttype : srctype,
				  srcvar, off0);
	  else if (!STRICT_ALIGNMENT)
	    {
	      srctype = build_aligned_type (TYPE_MAIN_VARIANT (desttype),
					    src_align);
	      srcvar = fold_build2 (MEM_REF, srctype, srcvar, off0);
	    }
	  else
	    srcvar = NULL_TREE;
	}
      else
	srcvar = NULL_TREE;

      if (srcvar == NULL_TREE && destvar == NULL_TREE)
	return false;

      if (srcvar == NULL_TREE)
	{
	  STRIP_NOPS (src);
	  if (src_align >= TYPE_ALIGN (desttype))
	    srcvar = fold_build2 (MEM_REF, desttype, src, off0);
	  else
	    {
	      if (STRICT_ALIGNMENT)
		return false;
	      srctype = build_aligned_type (TYPE_MAIN_VARIANT (desttype),
					    src_align);
	      srcvar = fold_build2 (MEM_REF, srctype, src, off0);
	    }
	}
      else if (destvar == NULL_TREE)
	{
	  STRIP_NOPS (dest);
	  if (dest_align >= TYPE_ALIGN (srctype))
	    destvar = fold_build2 (MEM_REF, srctype, dest, off0);
	  else
	    {
	      if (STRICT_ALIGNMENT)
		return false;
	      desttype = build_aligned_type (TYPE_MAIN_VARIANT (srctype),
					     dest_align);
	      destvar = fold_build2 (MEM_REF, desttype, dest, off0);
	    }
	}

      gimple new_stmt;
      if (is_gimple_reg_type (TREE_TYPE (srcvar)))
	{
	  new_stmt = gimple_build_assign (NULL_TREE, srcvar);
	  if (gimple_in_ssa_p (cfun))
	    srcvar = make_ssa_name (TREE_TYPE (srcvar), new_stmt);
	  else
	    srcvar = create_tmp_reg (TREE_TYPE (srcvar));
	  gimple_assign_set_lhs (new_stmt, srcvar);
	  gimple_set_vuse (new_stmt, gimple_vuse (stmt));
	  gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT);
	}
      new_stmt = gimple_build_assign (destvar, srcvar);
      gimple_set_vuse (new_stmt, gimple_vuse (stmt));
      gimple_set_vdef (new_stmt, gimple_vdef (stmt));
      if (gimple_vdef (new_stmt)
	  && TREE_CODE (gimple_vdef (new_stmt)) == SSA_NAME)
	SSA_NAME_DEF_STMT (gimple_vdef (new_stmt)) = new_stmt;
      if (!lhs)
	{
	  gsi_replace (gsi, new_stmt, false);
	  return true;
	}
      gsi_insert_before (gsi, new_stmt, GSI_SAME_STMT);
    }

done:
  if (endp == 0 || endp == 3)
    len = NULL_TREE;
  else if (endp == 2)
    len = fold_build2_loc (loc, MINUS_EXPR, TREE_TYPE (len), len,
			   ssize_int (1));
  if (endp == 2 || endp == 1)
    dest = fold_build_pointer_plus_loc (loc, dest, len);

  dest = force_gimple_operand_gsi (gsi, dest, false, NULL_TREE, true,
				   GSI_SAME_STMT);
  gimple repl = gimple_build_assign (lhs, dest);
  gsi_replace (gsi, repl, false);
  return true;
}

/* Fold function call to builtin memset or bzero at *GSI setting the
   memory of size LEN to VAL.  Return whether a simplification was made.  */

static bool
gimple_fold_builtin_memset (gimple_stmt_iterator *gsi, tree c, tree len)
{
  gimple stmt = gsi_stmt (*gsi);
  tree etype;
  unsigned HOST_WIDE_INT length, cval;

  /* If the LEN parameter is zero, return DEST.  */
  if (integer_zerop (len))
    {
      replace_call_with_value (gsi, gimple_call_arg (stmt, 0));
      return true;
    }

  if (! tree_fits_uhwi_p (len))
    return false;

  if (TREE_CODE (c) != INTEGER_CST)
    return false;

  tree dest = gimple_call_arg (stmt, 0);
  tree var = dest;
  if (TREE_CODE (var) != ADDR_EXPR)
    return false;

  var = TREE_OPERAND (var, 0);
  if (TREE_THIS_VOLATILE (var))
    return false;

  etype = TREE_TYPE (var);
  if (TREE_CODE (etype) == ARRAY_TYPE)
    etype = TREE_TYPE (etype);

  if (!INTEGRAL_TYPE_P (etype)
      && !POINTER_TYPE_P (etype))
    return NULL_TREE;

  if (! var_decl_component_p (var))
    return NULL_TREE;

  length = tree_to_uhwi (len);
  if (GET_MODE_SIZE (TYPE_MODE (etype)) != length
      || get_pointer_alignment (dest) / BITS_PER_UNIT < length)
    return NULL_TREE;

  if (length > HOST_BITS_PER_WIDE_INT / BITS_PER_UNIT)
    return NULL_TREE;

  if (integer_zerop (c))
    cval = 0;
  else
    {
      if (CHAR_BIT != 8 || BITS_PER_UNIT != 8 || HOST_BITS_PER_WIDE_INT > 64)
	return NULL_TREE;

      cval = TREE_INT_CST_LOW (c);
      cval &= 0xff;
      cval |= cval << 8;
      cval |= cval << 16;
      cval |= (cval << 31) << 1;
    }

  var = fold_build2 (MEM_REF, etype, dest, build_int_cst (ptr_type_node, 0));
  gimple store = gimple_build_assign (var, build_int_cst_type (etype, cval));
  gimple_set_vuse (store, gimple_vuse (stmt));
  tree vdef = gimple_vdef (stmt);
  if (vdef && TREE_CODE (vdef) == SSA_NAME)
    {
      gimple_set_vdef (store, gimple_vdef (stmt));
      SSA_NAME_DEF_STMT (gimple_vdef (stmt)) = store;
    }
  gsi_insert_before (gsi, store, GSI_SAME_STMT);
  if (gimple_call_lhs (stmt))
    {
      gimple asgn = gimple_build_assign (gimple_call_lhs (stmt), dest);
      gsi_replace (gsi, asgn, false);
    }
  else
    {
      gimple_stmt_iterator gsi2 = *gsi;
      gsi_prev (gsi);
      gsi_remove (&gsi2, true);
    }

  return true;
}


/* Return the string length, maximum string length or maximum value of
   ARG in LENGTH.
   If ARG is an SSA name variable, follow its use-def chains.  If LENGTH
   is not NULL and, for TYPE == 0, its value is not equal to the length
   we determine or if we are unable to determine the length or value,
   return false.  VISITED is a bitmap of visited variables.
   TYPE is 0 if string length should be returned, 1 for maximum string
   length and 2 for maximum value ARG can have.  */

static bool
get_maxval_strlen (tree arg, tree *length, bitmap *visited, int type)
{
  tree var, val;
  gimple def_stmt;

  if (TREE_CODE (arg) != SSA_NAME)
    {
      /* We can end up with &(*iftmp_1)[0] here as well, so handle it.  */
      if (TREE_CODE (arg) == ADDR_EXPR
	  && TREE_CODE (TREE_OPERAND (arg, 0)) == ARRAY_REF
	  && integer_zerop (TREE_OPERAND (TREE_OPERAND (arg, 0), 1)))
	{
	  tree aop0 = TREE_OPERAND (TREE_OPERAND (arg, 0), 0);
	  if (TREE_CODE (aop0) == INDIRECT_REF
	      && TREE_CODE (TREE_OPERAND (aop0, 0)) == SSA_NAME)
	    return get_maxval_strlen (TREE_OPERAND (aop0, 0),
				      length, visited, type);
	}

      if (type == 2)
	{
	  val = arg;
	  if (TREE_CODE (val) != INTEGER_CST
	      || tree_int_cst_sgn (val) < 0)
	    return false;
	}
      else
	val = c_strlen (arg, 1);
      if (!val)
	return false;

      if (*length)
	{
	  if (type > 0)
	    {
	      if (TREE_CODE (*length) != INTEGER_CST
		  || TREE_CODE (val) != INTEGER_CST)
		return false;

	      if (tree_int_cst_lt (*length, val))
		*length = val;
	      return true;
	    }
	  else if (simple_cst_equal (val, *length) != 1)
	    return false;
	}

      *length = val;
      return true;
    }

  /* If ARG is registered for SSA update we cannot look at its defining
     statement.  */
  if (name_registered_for_update_p (arg))
    return false;

  /* If we were already here, break the infinite cycle.  */
  if (!*visited)
    *visited = BITMAP_ALLOC (NULL);
  if (!bitmap_set_bit (*visited, SSA_NAME_VERSION (arg)))
    return true;

  var = arg;
  def_stmt = SSA_NAME_DEF_STMT (var);

  switch (gimple_code (def_stmt))
    {
      case GIMPLE_ASSIGN:
        /* The RHS of the statement defining VAR must either have a
           constant length or come from another SSA_NAME with a constant
           length.  */
        if (gimple_assign_single_p (def_stmt)
            || gimple_assign_unary_nop_p (def_stmt))
          {
            tree rhs = gimple_assign_rhs1 (def_stmt);
            return get_maxval_strlen (rhs, length, visited, type);
          }
	else if (gimple_assign_rhs_code (def_stmt) == COND_EXPR)
	  {
	    tree op2 = gimple_assign_rhs2 (def_stmt);
	    tree op3 = gimple_assign_rhs3 (def_stmt);
	    return get_maxval_strlen (op2, length, visited, type)
		   && get_maxval_strlen (op3, length, visited, type);
          }
        return false;

      case GIMPLE_PHI:
	{
	  /* All the arguments of the PHI node must have the same constant
	     length.  */
	  unsigned i;

	  for (i = 0; i < gimple_phi_num_args (def_stmt); i++)
          {
            tree arg = gimple_phi_arg (def_stmt, i)->def;

            /* If this PHI has itself as an argument, we cannot
               determine the string length of this argument.  However,
               if we can find a constant string length for the other
               PHI args then we can still be sure that this is a
               constant string length.  So be optimistic and just
               continue with the next argument.  */
            if (arg == gimple_phi_result (def_stmt))
              continue;

            if (!get_maxval_strlen (arg, length, visited, type))
              return false;
          }
        }
        return true;

      default:
        return false;
    }
}

tree
get_maxval_strlen (tree arg, int type)
{
  bitmap visited = NULL;
  tree len = NULL_TREE;
  if (!get_maxval_strlen (arg, &len, &visited, type))
    len = NULL_TREE;
  if (visited)
    BITMAP_FREE (visited);

  return len;
}


/* Fold function call to builtin strcpy with arguments DEST and SRC.
   If LEN is not NULL, it represents the length of the string to be
   copied.  Return NULL_TREE if no simplification can be made.  */

static bool
gimple_fold_builtin_strcpy (gimple_stmt_iterator *gsi,
			    tree dest, tree src)
{
  location_t loc = gimple_location (gsi_stmt (*gsi));
  tree fn;

  /* If SRC and DEST are the same (and not volatile), return DEST.  */
  if (operand_equal_p (src, dest, 0))
    {
      replace_call_with_value (gsi, dest);
      return true;
    }

  if (optimize_function_for_size_p (cfun))
    return false;

  fn = builtin_decl_implicit (BUILT_IN_MEMCPY);
  if (!fn)
    return false;

  tree len = get_maxval_strlen (src, 0);
  if (!len)
    return false;

  len = fold_convert_loc (loc, size_type_node, len);
  len = size_binop_loc (loc, PLUS_EXPR, len, build_int_cst (size_type_node, 1));
  len = force_gimple_operand_gsi (gsi, len, true,
				  NULL_TREE, true, GSI_SAME_STMT);
  gimple repl = gimple_build_call (fn, 3, dest, src, len);
  replace_call_with_call_and_fold (gsi, repl);
  return true;
}

/* Fold function call to builtin strncpy with arguments DEST, SRC, and LEN.
   If SLEN is not NULL, it represents the length of the source string.
   Return NULL_TREE if no simplification can be made.  */

static bool
gimple_fold_builtin_strncpy (gimple_stmt_iterator *gsi,
			     tree dest, tree src, tree len)
{
  location_t loc = gimple_location (gsi_stmt (*gsi));
  tree fn;

  /* If the LEN parameter is zero, return DEST.  */
  if (integer_zerop (len))
    {
      replace_call_with_value (gsi, dest);
      return true;
    }

  /* We can't compare slen with len as constants below if len is not a
     constant.  */
  if (TREE_CODE (len) != INTEGER_CST)
    return false;

  /* Now, we must be passed a constant src ptr parameter.  */
  tree slen = get_maxval_strlen (src, 0);
  if (!slen || TREE_CODE (slen) != INTEGER_CST)
    return false;

  slen = size_binop_loc (loc, PLUS_EXPR, slen, ssize_int (1));

  /* We do not support simplification of this case, though we do
     support it when expanding trees into RTL.  */
  /* FIXME: generate a call to __builtin_memset.  */
  if (tree_int_cst_lt (slen, len))
    return false;

  /* OK transform into builtin memcpy.  */
  fn = builtin_decl_implicit (BUILT_IN_MEMCPY);
  if (!fn)
    return false;

  len = fold_convert_loc (loc, size_type_node, len);
  len = force_gimple_operand_gsi (gsi, len, true,
				  NULL_TREE, true, GSI_SAME_STMT);
  gimple repl = gimple_build_call (fn, 3, dest, src, len);
  replace_call_with_call_and_fold (gsi, repl);
  return true;
}

/* Simplify a call to the strcat builtin.  DST and SRC are the arguments
   to the call.

   Return NULL_TREE if no simplification was possible, otherwise return the
   simplified form of the call as a tree.

   The simplified form may be a constant or other expression which
   computes the same value, but in a more efficient manner (including
   calls to other builtin functions).

   The call may contain arguments which need to be evaluated, but
   which are not useful to determine the result of the call.  In
   this case we return a chain of COMPOUND_EXPRs.  The LHS of each
   COMPOUND_EXPR will be an argument which must be evaluated.
   COMPOUND_EXPRs are chained through their RHS.  The RHS of the last
   COMPOUND_EXPR in the chain will contain the tree for the simplified
   form of the builtin function call.  */

static bool
gimple_fold_builtin_strcat (gimple_stmt_iterator *gsi, tree dst, tree src)
{
  gimple stmt = gsi_stmt (*gsi);
  location_t loc = gimple_location (stmt);

  const char *p = c_getstr (src);

  /* If the string length is zero, return the dst parameter.  */
  if (p && *p == '\0')
    {
      replace_call_with_value (gsi, dst);
      return true;
    }

  if (!optimize_bb_for_speed_p (gimple_bb (stmt)))
    return false;

  /* See if we can store by pieces into (dst + strlen(dst)).  */
  tree newdst;
  tree strlen_fn = builtin_decl_implicit (BUILT_IN_STRLEN);
  tree memcpy_fn = builtin_decl_implicit (BUILT_IN_MEMCPY);

  if (!strlen_fn || !memcpy_fn)
    return false;

  /* If the length of the source string isn't computable don't
     split strcat into strlen and memcpy.  */
  tree len = get_maxval_strlen (src, 0);
  if (! len)
    return false;

  /* Create strlen (dst).  */
  gimple_seq stmts = NULL, stmts2;
  gimple repl = gimple_build_call (strlen_fn, 1, dst);
  gimple_set_location (repl, loc);
  if (gimple_in_ssa_p (cfun))
    newdst = make_ssa_name (size_type_node);
  else
    newdst = create_tmp_reg (size_type_node);
  gimple_call_set_lhs (repl, newdst);
  gimple_seq_add_stmt_without_update (&stmts, repl);

  /* Create (dst p+ strlen (dst)).  */
  newdst = fold_build_pointer_plus_loc (loc, dst, newdst);
  newdst = force_gimple_operand (newdst, &stmts2, true, NULL_TREE);
  gimple_seq_add_seq_without_update (&stmts, stmts2);

  len = fold_convert_loc (loc, size_type_node, len);
  len = size_binop_loc (loc, PLUS_EXPR, len,
			build_int_cst (size_type_node, 1));
  len = force_gimple_operand (len, &stmts2, true, NULL_TREE);
  gimple_seq_add_seq_without_update (&stmts, stmts2);

  repl = gimple_build_call (memcpy_fn, 3, newdst, src, len);
  gimple_seq_add_stmt_without_update (&stmts, repl);
  if (gimple_call_lhs (stmt))
    {
      repl = gimple_build_assign (gimple_call_lhs (stmt), dst);
      gimple_seq_add_stmt_without_update (&stmts, repl);
      gsi_replace_with_seq_vops (gsi, stmts);
      /* gsi now points at the assignment to the lhs, get a
         stmt iterator to the memcpy call.
	 ???  We can't use gsi_for_stmt as that doesn't work when the
	 CFG isn't built yet.  */
      gimple_stmt_iterator gsi2 = *gsi;
      gsi_prev (&gsi2);
      fold_stmt (&gsi2);
    }
  else
    {
      gsi_replace_with_seq_vops (gsi, stmts);
      fold_stmt (gsi);
    }
  return true;
}

/* Fold a call to the __strcat_chk builtin FNDECL.  DEST, SRC, and SIZE
   are the arguments to the call.  */

static bool
gimple_fold_builtin_strcat_chk (gimple_stmt_iterator *gsi)
{
  gimple stmt = gsi_stmt (*gsi);
  tree dest = gimple_call_arg (stmt, 0);
  tree src = gimple_call_arg (stmt, 1);
  tree size = gimple_call_arg (stmt, 2);
  tree fn;
  const char *p;


  p = c_getstr (src);
  /* If the SRC parameter is "", return DEST.  */
  if (p && *p == '\0')
    {
      replace_call_with_value (gsi, dest);
      return true;
    }

  if (! tree_fits_uhwi_p (size) || ! integer_all_onesp (size))
    return false;

  /* If __builtin_strcat_chk is used, assume strcat is available.  */
  fn = builtin_decl_explicit (BUILT_IN_STRCAT);
  if (!fn)
    return false;

  gimple repl = gimple_build_call (fn, 2, dest, src);
  replace_call_with_call_and_fold (gsi, repl);
  return true;
}

/* Simplify a call to the strncat builtin.  */

static bool
gimple_fold_builtin_strncat (gimple_stmt_iterator *gsi)
{
  gcall *stmt = as_a <gcall *> (gsi_stmt (*gsi));
  tree dst = gimple_call_arg (stmt, 0);
  tree src = gimple_call_arg (stmt, 1);
  tree len = gimple_call_arg (stmt, 2);

  const char *p = c_getstr (src);

  /* If the requested length is zero, or the src parameter string
     length is zero, return the dst parameter.  */
  if (integer_zerop (len) || (p && *p == '\0'))
    {
      replace_call_with_value (gsi, dst);
      return true;
    }

  /* If the requested len is greater than or equal to the string
     length, call strcat.  */
  if (TREE_CODE (len) == INTEGER_CST && p
      && compare_tree_int (len, strlen (p)) >= 0)
    {
      tree fn = builtin_decl_implicit (BUILT_IN_STRCAT);

      /* If the replacement _DECL isn't initialized, don't do the
	 transformation.  */
      if (!fn)
	return false;

      gcall *repl = gimple_build_call (fn, 2, dst, src);
      replace_call_with_call_and_fold (gsi, repl);
      return true;
    }

  return false;
}

/* Fold a call to the __strncat_chk builtin with arguments DEST, SRC,
   LEN, and SIZE.  */

static bool 
gimple_fold_builtin_strncat_chk (gimple_stmt_iterator *gsi)
{
  gimple stmt = gsi_stmt (*gsi);
  tree dest = gimple_call_arg (stmt, 0);
  tree src = gimple_call_arg (stmt, 1);
  tree len = gimple_call_arg (stmt, 2);
  tree size = gimple_call_arg (stmt, 3);
  tree fn;
  const char *p;

  p = c_getstr (src);
  /* If the SRC parameter is "" or if LEN is 0, return DEST.  */
  if ((p && *p == '\0')
      || integer_zerop (len))
    {
      replace_call_with_value (gsi, dest);
      return true;
    }

  if (! tree_fits_uhwi_p (size))
    return false;

  if (! integer_all_onesp (size))
    {
      tree src_len = c_strlen (src, 1);
      if (src_len
	  && tree_fits_uhwi_p (src_len)
	  && tree_fits_uhwi_p (len)
	  && ! tree_int_cst_lt (len, src_len))
	{
	  /* If LEN >= strlen (SRC), optimize into __strcat_chk.  */
	  fn = builtin_decl_explicit (BUILT_IN_STRCAT_CHK);
	  if (!fn)
	    return false;

	  gimple repl = gimple_build_call (fn, 3, dest, src, size);
	  replace_call_with_call_and_fold (gsi, repl);
	  return true;
	}
      return false;
    }

  /* If __builtin_strncat_chk is used, assume strncat is available.  */
  fn = builtin_decl_explicit (BUILT_IN_STRNCAT);
  if (!fn)
    return false;

  gimple repl = gimple_build_call (fn, 3, dest, src, len);
  replace_call_with_call_and_fold (gsi, repl);
  return true;
}

/* Fold a call to the fputs builtin.  ARG0 and ARG1 are the arguments
   to the call.  IGNORE is true if the value returned
   by the builtin will be ignored.  UNLOCKED is true is true if this
   actually a call to fputs_unlocked.  If LEN in non-NULL, it represents
   the known length of the string.  Return NULL_TREE if no simplification
   was possible.  */

static bool
gimple_fold_builtin_fputs (gimple_stmt_iterator *gsi,
			   tree arg0, tree arg1,
			   bool unlocked)
{
  gimple stmt = gsi_stmt (*gsi);

  /* If we're using an unlocked function, assume the other unlocked
     functions exist explicitly.  */
  tree const fn_fputc = (unlocked
			 ? builtin_decl_explicit (BUILT_IN_FPUTC_UNLOCKED)
			 : builtin_decl_implicit (BUILT_IN_FPUTC));
  tree const fn_fwrite = (unlocked
			  ? builtin_decl_explicit (BUILT_IN_FWRITE_UNLOCKED)
			  : builtin_decl_implicit (BUILT_IN_FWRITE));

  /* If the return value is used, don't do the transformation.  */
  if (gimple_call_lhs (stmt))
    return false;

  /* Get the length of the string passed to fputs.  If the length
     can't be determined, punt.  */
  tree len = get_maxval_strlen (arg0, 0);
  if (!len
      || TREE_CODE (len) != INTEGER_CST)
    return false;

  switch (compare_tree_int (len, 1))
    {
    case -1: /* length is 0, delete the call entirely .  */
      replace_call_with_value (gsi, integer_zero_node);
      return true;

    case 0: /* length is 1, call fputc.  */
      {
	const char *p = c_getstr (arg0);
	if (p != NULL)
	  {
	    if (!fn_fputc)
	      return false;

	    gimple repl = gimple_build_call (fn_fputc, 2,
					     build_int_cst
					     (integer_type_node, p[0]), arg1);
	    replace_call_with_call_and_fold (gsi, repl);
	    return true;
	  }
      }
      /* FALLTHROUGH */
    case 1: /* length is greater than 1, call fwrite.  */
      {
	/* If optimizing for size keep fputs.  */
	if (optimize_function_for_size_p (cfun))
	  return false;
	/* New argument list transforming fputs(string, stream) to
	   fwrite(string, 1, len, stream).  */
	if (!fn_fwrite)
	  return false;

	gimple repl = gimple_build_call (fn_fwrite, 4, arg0,
					 size_one_node, len, arg1);
	replace_call_with_call_and_fold (gsi, repl);
	return true;
      }
    default:
      gcc_unreachable ();
    }
  return false;
}

/* Fold a call to the __mem{cpy,pcpy,move,set}_chk builtin.
   DEST, SRC, LEN, and SIZE are the arguments to the call.
   IGNORE is true, if return value can be ignored.  FCODE is the BUILT_IN_*
   code of the builtin.  If MAXLEN is not NULL, it is maximum length
   passed as third argument.  */

static bool
gimple_fold_builtin_memory_chk (gimple_stmt_iterator *gsi,
				tree dest, tree src, tree len, tree size,
				enum built_in_function fcode)
{
  gimple stmt = gsi_stmt (*gsi);
  location_t loc = gimple_location (stmt);
  bool ignore = gimple_call_lhs (stmt) == NULL_TREE;
  tree fn;

  /* If SRC and DEST are the same (and not volatile), return DEST
     (resp. DEST+LEN for __mempcpy_chk).  */
  if (fcode != BUILT_IN_MEMSET_CHK && operand_equal_p (src, dest, 0))
    {
      if (fcode != BUILT_IN_MEMPCPY_CHK)
	{
	  replace_call_with_value (gsi, dest);
	  return true;
	}
      else
	{
	  tree temp = fold_build_pointer_plus_loc (loc, dest, len);
	  temp = force_gimple_operand_gsi (gsi, temp,
					   false, NULL_TREE, true,
					   GSI_SAME_STMT);
	  replace_call_with_value (gsi, temp);
	  return true;
	}
    }

  if (! tree_fits_uhwi_p (size))
    return false;

  tree maxlen = get_maxval_strlen (len, 2);
  if (! integer_all_onesp (size))
    {
      if (! tree_fits_uhwi_p (len))
	{
	  /* If LEN is not constant, try MAXLEN too.
	     For MAXLEN only allow optimizing into non-_ocs function
	     if SIZE is >= MAXLEN, never convert to __ocs_fail ().  */
	  if (maxlen == NULL_TREE || ! tree_fits_uhwi_p (maxlen))
	    {
	      if (fcode == BUILT_IN_MEMPCPY_CHK && ignore)
		{
		  /* (void) __mempcpy_chk () can be optimized into
		     (void) __memcpy_chk ().  */
		  fn = builtin_decl_explicit (BUILT_IN_MEMCPY_CHK);
		  if (!fn)
		    return false;

		  gimple repl = gimple_build_call (fn, 4, dest, src, len, size);
		  replace_call_with_call_and_fold (gsi, repl);
		  return true;
		}
	      return false;
	    }
	}
      else
	maxlen = len;

      if (tree_int_cst_lt (size, maxlen))
	return false;
    }

  fn = NULL_TREE;
  /* If __builtin_mem{cpy,pcpy,move,set}_chk is used, assume
     mem{cpy,pcpy,move,set} is available.  */
  switch (fcode)
    {
    case BUILT_IN_MEMCPY_CHK:
      fn = builtin_decl_explicit (BUILT_IN_MEMCPY);
      break;
    case BUILT_IN_MEMPCPY_CHK:
      fn = builtin_decl_explicit (BUILT_IN_MEMPCPY);
      break;
    case BUILT_IN_MEMMOVE_CHK:
      fn = builtin_decl_explicit (BUILT_IN_MEMMOVE);
      break;
    case BUILT_IN_MEMSET_CHK:
      fn = builtin_decl_explicit (BUILT_IN_MEMSET);
      break;
    default:
      break;
    }

  if (!fn)
    return false;

  gimple repl = gimple_build_call (fn, 3, dest, src, len);
  replace_call_with_call_and_fold (gsi, repl);
  return true;
}

/* Fold a call to the __st[rp]cpy_chk builtin.
   DEST, SRC, and SIZE are the arguments to the call.
   IGNORE is true if return value can be ignored.  FCODE is the BUILT_IN_*
   code of the builtin.  If MAXLEN is not NULL, it is maximum length of
   strings passed as second argument.  */

static bool
gimple_fold_builtin_stxcpy_chk (gimple_stmt_iterator *gsi,
				tree dest,
				tree src, tree size,
				enum built_in_function fcode)
{
  gimple stmt = gsi_stmt (*gsi);
  location_t loc = gimple_location (stmt);
  bool ignore = gimple_call_lhs (stmt) == NULL_TREE;
  tree len, fn;

  /* If SRC and DEST are the same (and not volatile), return DEST.  */
  if (fcode == BUILT_IN_STRCPY_CHK && operand_equal_p (src, dest, 0))
    {
      replace_call_with_value (gsi, dest);
      return true;
    }

  if (! tree_fits_uhwi_p (size))
    return false;

  tree maxlen = get_maxval_strlen (src, 1);
  if (! integer_all_onesp (size))
    {
      len = c_strlen (src, 1);
      if (! len || ! tree_fits_uhwi_p (len))
	{
	  /* If LEN is not constant, try MAXLEN too.
	     For MAXLEN only allow optimizing into non-_ocs function
	     if SIZE is >= MAXLEN, never convert to __ocs_fail ().  */
	  if (maxlen == NULL_TREE || ! tree_fits_uhwi_p (maxlen))
	    {
	      if (fcode == BUILT_IN_STPCPY_CHK)
		{
		  if (! ignore)
		    return false;

		  /* If return value of __stpcpy_chk is ignored,
		     optimize into __strcpy_chk.  */
		  fn = builtin_decl_explicit (BUILT_IN_STRCPY_CHK);
		  if (!fn)
		    return false;

		  gimple repl = gimple_build_call (fn, 3, dest, src, size);
		  replace_call_with_call_and_fold (gsi, repl);
		  return true;
		}

	      if (! len || TREE_SIDE_EFFECTS (len))
		return false;

	      /* If c_strlen returned something, but not a constant,
		 transform __strcpy_chk into __memcpy_chk.  */
	      fn = builtin_decl_explicit (BUILT_IN_MEMCPY_CHK);
	      if (!fn)
		return false;

	      len = fold_convert_loc (loc, size_type_node, len);
	      len = size_binop_loc (loc, PLUS_EXPR, len,
				    build_int_cst (size_type_node, 1));
	      len = force_gimple_operand_gsi (gsi, len, true, NULL_TREE,
					      true, GSI_SAME_STMT);
	      gimple repl = gimple_build_call (fn, 4, dest, src, len, size);
	      replace_call_with_call_and_fold (gsi, repl);
	      return true;
	    }
	}
      else
	maxlen = len;

      if (! tree_int_cst_lt (maxlen, size))
	return false;
    }

  /* If __builtin_st{r,p}cpy_chk is used, assume st{r,p}cpy is available.  */
  fn = builtin_decl_explicit (fcode == BUILT_IN_STPCPY_CHK
			      ? BUILT_IN_STPCPY : BUILT_IN_STRCPY);
  if (!fn)
    return false;

  gimple repl = gimple_build_call (fn, 2, dest, src);
  replace_call_with_call_and_fold (gsi, repl);
  return true;
}

/* Fold a call to the __st{r,p}ncpy_chk builtin.  DEST, SRC, LEN, and SIZE
   are the arguments to the call.  If MAXLEN is not NULL, it is maximum
   length passed as third argument. IGNORE is true if return value can be
   ignored. FCODE is the BUILT_IN_* code of the builtin. */

static bool
gimple_fold_builtin_stxncpy_chk (gimple_stmt_iterator *gsi,
				 tree dest, tree src,
				 tree len, tree size,
				 enum built_in_function fcode)
{
  gimple stmt = gsi_stmt (*gsi);
  bool ignore = gimple_call_lhs (stmt) == NULL_TREE;
  tree fn;

  if (fcode == BUILT_IN_STPNCPY_CHK && ignore)
    {
       /* If return value of __stpncpy_chk is ignored,
          optimize into __strncpy_chk.  */
       fn = builtin_decl_explicit (BUILT_IN_STRNCPY_CHK);
       if (fn)
	 {
	   gimple repl = gimple_build_call (fn, 4, dest, src, len, size);
	   replace_call_with_call_and_fold (gsi, repl);
	   return true;
	 }
    }

  if (! tree_fits_uhwi_p (size))
    return false;

  tree maxlen = get_maxval_strlen (len, 2);
  if (! integer_all_onesp (size))
    {
      if (! tree_fits_uhwi_p (len))
	{
	  /* If LEN is not constant, try MAXLEN too.
	     For MAXLEN only allow optimizing into non-_ocs function
	     if SIZE is >= MAXLEN, never convert to __ocs_fail ().  */
	  if (maxlen == NULL_TREE || ! tree_fits_uhwi_p (maxlen))
	    return false;
	}
      else
	maxlen = len;

      if (tree_int_cst_lt (size, maxlen))
	return false;
    }

  /* If __builtin_st{r,p}ncpy_chk is used, assume st{r,p}ncpy is available.  */
  fn = builtin_decl_explicit (fcode == BUILT_IN_STPNCPY_CHK
			      ? BUILT_IN_STPNCPY : BUILT_IN_STRNCPY);
  if (!fn)
    return false;

  gimple repl = gimple_build_call (fn, 3, dest, src, len);
  replace_call_with_call_and_fold (gsi, repl);
  return true;
}

/* Fold function call to builtin stpcpy with arguments DEST and SRC.
   Return NULL_TREE if no simplification can be made.  */

static bool
gimple_fold_builtin_stpcpy (gimple_stmt_iterator *gsi)
{
  gcall *stmt = as_a <gcall *> (gsi_stmt (*gsi));
  location_t loc = gimple_location (stmt);
  tree dest = gimple_call_arg (stmt, 0);
  tree src = gimple_call_arg (stmt, 1);
  tree fn, len, lenp1;

  /* If the result is unused, replace stpcpy with strcpy.  */
  if (gimple_call_lhs (stmt) == NULL_TREE)
    {
      tree fn = builtin_decl_implicit (BUILT_IN_STRCPY);
      if (!fn)
	return false;
      gimple_call_set_fndecl (stmt, fn);
      fold_stmt (gsi);
      return true;
    }

  len = c_strlen (src, 1);
  if (!len
      || TREE_CODE (len) != INTEGER_CST)
    return false;

  if (optimize_function_for_size_p (cfun)
      /* If length is zero it's small enough.  */
      && !integer_zerop (len))
    return false;

  /* If the source has a known length replace stpcpy with memcpy.  */
  fn = builtin_decl_implicit (BUILT_IN_MEMCPY);
  if (!fn)
    return false;

  gimple_seq stmts = NULL;
  tree tem = gimple_convert (&stmts, loc, size_type_node, len);
  lenp1 = gimple_build (&stmts, loc, PLUS_EXPR, size_type_node,
			tem, build_int_cst (size_type_node, 1));
  gsi_insert_seq_before (gsi, stmts, GSI_SAME_STMT);
  gcall *repl = gimple_build_call (fn, 3, dest, src, lenp1);
  gimple_set_vuse (repl, gimple_vuse (stmt));
  gimple_set_vdef (repl, gimple_vdef (stmt));
  if (gimple_vdef (repl)
      && TREE_CODE (gimple_vdef (repl)) == SSA_NAME)
    SSA_NAME_DEF_STMT (gimple_vdef (repl)) = repl;
  gsi_insert_before (gsi, repl, GSI_SAME_STMT);
  /* Replace the result with dest + len.  */
  stmts = NULL;
  tem = gimple_convert (&stmts, loc, sizetype, len);
  gsi_insert_seq_before (gsi, stmts, GSI_SAME_STMT);
  gassign *ret = gimple_build_assign (gimple_call_lhs (stmt),
				      POINTER_PLUS_EXPR, dest, tem);
  gsi_replace (gsi, ret, false);
  /* Finally fold the memcpy call.  */
  gimple_stmt_iterator gsi2 = *gsi;
  gsi_prev (&gsi2);
  fold_stmt (&gsi2);
  return true;
}

/* Fold a call EXP to {,v}snprintf having NARGS passed as ARGS.  Return
   NULL_TREE if a normal call should be emitted rather than expanding
   the function inline.  FCODE is either BUILT_IN_SNPRINTF_CHK or
   BUILT_IN_VSNPRINTF_CHK.  If MAXLEN is not NULL, it is maximum length
   passed as second argument.  */

static bool
gimple_fold_builtin_snprintf_chk (gimple_stmt_iterator *gsi,
				  enum built_in_function fcode)
{
  gcall *stmt = as_a <gcall *> (gsi_stmt (*gsi));
  tree dest, size, len, fn, fmt, flag;
  const char *fmt_str;

  /* Verify the required arguments in the original call.  */
  if (gimple_call_num_args (stmt) < 5)
    return false;

  dest = gimple_call_arg (stmt, 0);
  len = gimple_call_arg (stmt, 1);
  flag = gimple_call_arg (stmt, 2);
  size = gimple_call_arg (stmt, 3);
  fmt = gimple_call_arg (stmt, 4);

  if (! tree_fits_uhwi_p (size))
    return false;

  if (! integer_all_onesp (size))
    {
      tree maxlen = get_maxval_strlen (len, 2);
      if (! tree_fits_uhwi_p (len))
	{
	  /* If LEN is not constant, try MAXLEN too.
	     For MAXLEN only allow optimizing into non-_ocs function
	     if SIZE is >= MAXLEN, never convert to __ocs_fail ().  */
	  if (maxlen == NULL_TREE || ! tree_fits_uhwi_p (maxlen))
	    return false;
	}
      else
	maxlen = len;

      if (tree_int_cst_lt (size, maxlen))
	return false;
    }

  if (!init_target_chars ())
    return false;

  /* Only convert __{,v}snprintf_chk to {,v}snprintf if flag is 0
     or if format doesn't contain % chars or is "%s".  */
  if (! integer_zerop (flag))
    {
      fmt_str = c_getstr (fmt);
      if (fmt_str == NULL)
	return false;
      if (strchr (fmt_str, target_percent) != NULL
	  && strcmp (fmt_str, target_percent_s))
	return false;
    }

  /* If __builtin_{,v}snprintf_chk is used, assume {,v}snprintf is
     available.  */
  fn = builtin_decl_explicit (fcode == BUILT_IN_VSNPRINTF_CHK
			      ? BUILT_IN_VSNPRINTF : BUILT_IN_SNPRINTF);
  if (!fn)
    return false;

  /* Replace the called function and the first 5 argument by 3 retaining
     trailing varargs.  */
  gimple_call_set_fndecl (stmt, fn);
  gimple_call_set_fntype (stmt, TREE_TYPE (fn));
  gimple_call_set_arg (stmt, 0, dest);
  gimple_call_set_arg (stmt, 1, len);
  gimple_call_set_arg (stmt, 2, fmt);
  for (unsigned i = 3; i < gimple_call_num_args (stmt) - 2; ++i)
    gimple_call_set_arg (stmt, i, gimple_call_arg (stmt, i + 2));
  gimple_set_num_ops (stmt, gimple_num_ops (stmt) - 2);
  fold_stmt (gsi);
  return true;
}

/* Fold a call EXP to __{,v}sprintf_chk having NARGS passed as ARGS.
   Return NULL_TREE if a normal call should be emitted rather than
   expanding the function inline.  FCODE is either BUILT_IN_SPRINTF_CHK
   or BUILT_IN_VSPRINTF_CHK.  */

static bool
gimple_fold_builtin_sprintf_chk (gimple_stmt_iterator *gsi,
				 enum built_in_function fcode)
{
  gcall *stmt = as_a <gcall *> (gsi_stmt (*gsi));
  tree dest, size, len, fn, fmt, flag;
  const char *fmt_str;
  unsigned nargs = gimple_call_num_args (stmt);

  /* Verify the required arguments in the original call.  */
  if (nargs < 4)
    return false;
  dest = gimple_call_arg (stmt, 0);
  flag = gimple_call_arg (stmt, 1);
  size = gimple_call_arg (stmt, 2);
  fmt = gimple_call_arg (stmt, 3);

  if (! tree_fits_uhwi_p (size))
    return false;

  len = NULL_TREE;

  if (!init_target_chars ())
    return false;

  /* Check whether the format is a literal string constant.  */
  fmt_str = c_getstr (fmt);
  if (fmt_str != NULL)
    {
      /* If the format doesn't contain % args or %%, we know the size.  */
      if (strchr (fmt_str, target_percent) == 0)
	{
	  if (fcode != BUILT_IN_SPRINTF_CHK || nargs == 4)
	    len = build_int_cstu (size_type_node, strlen (fmt_str));
	}
      /* If the format is "%s" and first ... argument is a string literal,
	 we know the size too.  */
      else if (fcode == BUILT_IN_SPRINTF_CHK
	       && strcmp (fmt_str, target_percent_s) == 0)
	{
	  tree arg;

	  if (nargs == 5)
	    {
	      arg = gimple_call_arg (stmt, 4);
	      if (POINTER_TYPE_P (TREE_TYPE (arg)))
		{
		  len = c_strlen (arg, 1);
		  if (! len || ! tree_fits_uhwi_p (len))
		    len = NULL_TREE;
		}
	    }
	}
    }

  if (! integer_all_onesp (size))
    {
      if (! len || ! tree_int_cst_lt (len, size))
	return false;
    }

  /* Only convert __{,v}sprintf_chk to {,v}sprintf if flag is 0
     or if format doesn't contain % chars or is "%s".  */
  if (! integer_zerop (flag))
    {
      if (fmt_str == NULL)
	return false;
      if (strchr (fmt_str, target_percent) != NULL
	  && strcmp (fmt_str, target_percent_s))
	return false;
    }

  /* If __builtin_{,v}sprintf_chk is used, assume {,v}sprintf is available.  */
  fn = builtin_decl_explicit (fcode == BUILT_IN_VSPRINTF_CHK
			      ? BUILT_IN_VSPRINTF : BUILT_IN_SPRINTF);
  if (!fn)
    return false;

  /* Replace the called function and the first 4 argument by 2 retaining
     trailing varargs.  */
  gimple_call_set_fndecl (stmt, fn);
  gimple_call_set_fntype (stmt, TREE_TYPE (fn));
  gimple_call_set_arg (stmt, 0, dest);
  gimple_call_set_arg (stmt, 1, fmt);
  for (unsigned i = 2; i < gimple_call_num_args (stmt) - 2; ++i)
    gimple_call_set_arg (stmt, i, gimple_call_arg (stmt, i + 2));
  gimple_set_num_ops (stmt, gimple_num_ops (stmt) - 2);
  fold_stmt (gsi);
  return true;
}

/* Simplify a call to the sprintf builtin with arguments DEST, FMT, and ORIG.
   ORIG may be null if this is a 2-argument call.  We don't attempt to
   simplify calls with more than 3 arguments.

   Return NULL_TREE if no simplification was possible, otherwise return the
   simplified form of the call as a tree.  If IGNORED is true, it means that
   the caller does not use the returned value of the function.  */

static bool
gimple_fold_builtin_sprintf (gimple_stmt_iterator *gsi)
{
  gimple stmt = gsi_stmt (*gsi);
  tree dest = gimple_call_arg (stmt, 0);
  tree fmt = gimple_call_arg (stmt, 1);
  tree orig = NULL_TREE;
  const char *fmt_str = NULL;

  /* Verify the required arguments in the original call.  We deal with two
     types of sprintf() calls: 'sprintf (str, fmt)' and
     'sprintf (dest, "%s", orig)'.  */
  if (gimple_call_num_args (stmt) > 3)
    return false;

  if (gimple_call_num_args (stmt) == 3)
    orig = gimple_call_arg (stmt, 2);

  /* Check whether the format is a literal string constant.  */
  fmt_str = c_getstr (fmt);
  if (fmt_str == NULL)
    return false;

  if (!init_target_chars ())
    return false;

  /* If the format doesn't contain % args or %%, use strcpy.  */
  if (strchr (fmt_str, target_percent) == NULL)
    {
      tree fn = builtin_decl_implicit (BUILT_IN_STRCPY);

      if (!fn)
	return false;

      /* Don't optimize sprintf (buf, "abc", ptr++).  */
      if (orig)
	return false;

      /* Convert sprintf (str, fmt) into strcpy (str, fmt) when
	 'format' is known to contain no % formats.  */
      gimple_seq stmts = NULL;
      gimple repl = gimple_build_call (fn, 2, dest, fmt);
      gimple_seq_add_stmt_without_update (&stmts, repl);
      if (gimple_call_lhs (stmt))
	{
	  repl = gimple_build_assign (gimple_call_lhs (stmt),
				      build_int_cst (integer_type_node,
						     strlen (fmt_str)));
	  gimple_seq_add_stmt_without_update (&stmts, repl);
	  gsi_replace_with_seq_vops (gsi, stmts);
	  /* gsi now points at the assignment to the lhs, get a
	     stmt iterator to the memcpy call.
	     ???  We can't use gsi_for_stmt as that doesn't work when the
	     CFG isn't built yet.  */
	  gimple_stmt_iterator gsi2 = *gsi;
	  gsi_prev (&gsi2);
	  fold_stmt (&gsi2);
	}
      else
	{
	  gsi_replace_with_seq_vops (gsi, stmts);
	  fold_stmt (gsi);
	}
      return true;
    }

  /* If the format is "%s", use strcpy if the result isn't used.  */
  else if (fmt_str && strcmp (fmt_str, target_percent_s) == 0)
    {
      tree fn;
      fn = builtin_decl_implicit (BUILT_IN_STRCPY);

      if (!fn)
	return false;

      /* Don't crash on sprintf (str1, "%s").  */
      if (!orig)
	return false;

      tree orig_len = NULL_TREE;
      if (gimple_call_lhs (stmt))
	{
	  orig_len = get_maxval_strlen (orig, 0);
	  if (!orig_len)
	    return false;
	}

      /* Convert sprintf (str1, "%s", str2) into strcpy (str1, str2).  */
      gimple_seq stmts = NULL;
      gimple repl = gimple_build_call (fn, 2, dest, orig);
      gimple_seq_add_stmt_without_update (&stmts, repl);
      if (gimple_call_lhs (stmt))
	{
	  if (!useless_type_conversion_p (integer_type_node,
					  TREE_TYPE (orig_len)))
	    orig_len = fold_convert (integer_type_node, orig_len);
	  repl = gimple_build_assign (gimple_call_lhs (stmt), orig_len);
	  gimple_seq_add_stmt_without_update (&stmts, repl);
	  gsi_replace_with_seq_vops (gsi, stmts);
	  /* gsi now points at the assignment to the lhs, get a
	     stmt iterator to the memcpy call.
	     ???  We can't use gsi_for_stmt as that doesn't work when the
	     CFG isn't built yet.  */
	  gimple_stmt_iterator gsi2 = *gsi;
	  gsi_prev (&gsi2);
	  fold_stmt (&gsi2);
	}
      else
	{
	  gsi_replace_with_seq_vops (gsi, stmts);
	  fold_stmt (gsi);
	}
      return true;
    }
  return false;
}

/* Simplify a call to the snprintf builtin with arguments DEST, DESTSIZE,
   FMT, and ORIG.  ORIG may be null if this is a 3-argument call.  We don't
   attempt to simplify calls with more than 4 arguments.

   Return NULL_TREE if no simplification was possible, otherwise return the
   simplified form of the call as a tree.  If IGNORED is true, it means that
   the caller does not use the returned value of the function.  */

static bool
gimple_fold_builtin_snprintf (gimple_stmt_iterator *gsi)
{
  gcall *stmt = as_a <gcall *> (gsi_stmt (*gsi));
  tree dest = gimple_call_arg (stmt, 0);
  tree destsize = gimple_call_arg (stmt, 1);
  tree fmt = gimple_call_arg (stmt, 2);
  tree orig = NULL_TREE;
  const char *fmt_str = NULL;

  if (gimple_call_num_args (stmt) > 4)
    return false;

  if (gimple_call_num_args (stmt) == 4)
    orig = gimple_call_arg (stmt, 3);

  if (!tree_fits_uhwi_p (destsize))
    return false;
  unsigned HOST_WIDE_INT destlen = tree_to_uhwi (destsize);

  /* Check whether the format is a literal string constant.  */
  fmt_str = c_getstr (fmt);
  if (fmt_str == NULL)
    return false;

  if (!init_target_chars ())
    return false;

  /* If the format doesn't contain % args or %%, use strcpy.  */
  if (strchr (fmt_str, target_percent) == NULL)
    {
      tree fn = builtin_decl_implicit (BUILT_IN_STRCPY);
      if (!fn)
	return false;

      /* Don't optimize snprintf (buf, 4, "abc", ptr++).  */
      if (orig)
	return false;

      /* We could expand this as
	 memcpy (str, fmt, cst - 1); str[cst - 1] = '\0';
	 or to
	 memcpy (str, fmt_with_nul_at_cstm1, cst);
	 but in the former case that might increase code size
	 and in the latter case grow .rodata section too much.
	 So punt for now.  */
      size_t len = strlen (fmt_str);
      if (len >= destlen)
	return false;

      gimple_seq stmts = NULL;
      gimple repl = gimple_build_call (fn, 2, dest, fmt);
      gimple_seq_add_stmt_without_update (&stmts, repl);
      if (gimple_call_lhs (stmt))
	{
	  repl = gimple_build_assign (gimple_call_lhs (stmt),
				      build_int_cst (integer_type_node, len));
	  gimple_seq_add_stmt_without_update (&stmts, repl);
	  gsi_replace_with_seq_vops (gsi, stmts);
	  /* gsi now points at the assignment to the lhs, get a
	     stmt iterator to the memcpy call.
	     ???  We can't use gsi_for_stmt as that doesn't work when the
	     CFG isn't built yet.  */
	  gimple_stmt_iterator gsi2 = *gsi;
	  gsi_prev (&gsi2);
	  fold_stmt (&gsi2);
	}
      else
	{
	  gsi_replace_with_seq_vops (gsi, stmts);
	  fold_stmt (gsi);
	}
      return true;
    }

  /* If the format is "%s", use strcpy if the result isn't used.  */
  else if (fmt_str && strcmp (fmt_str, target_percent_s) == 0)
    {
      tree fn = builtin_decl_implicit (BUILT_IN_STRCPY);
      if (!fn)
	return false;

      /* Don't crash on snprintf (str1, cst, "%s").  */
      if (!orig)
	return false;

      tree orig_len = get_maxval_strlen (orig, 0);
      if (!orig_len || TREE_CODE (orig_len) != INTEGER_CST)
	return false;

      /* We could expand this as
	 memcpy (str1, str2, cst - 1); str1[cst - 1] = '\0';
	 or to
	 memcpy (str1, str2_with_nul_at_cstm1, cst);
	 but in the former case that might increase code size
	 and in the latter case grow .rodata section too much.
	 So punt for now.  */
      if (compare_tree_int (orig_len, destlen) >= 0)
	return false;

      /* Convert snprintf (str1, cst, "%s", str2) into
	 strcpy (str1, str2) if strlen (str2) < cst.  */
      gimple_seq stmts = NULL;
      gimple repl = gimple_build_call (fn, 2, dest, orig);
      gimple_seq_add_stmt_without_update (&stmts, repl);
      if (gimple_call_lhs (stmt))
	{
	  if (!useless_type_conversion_p (integer_type_node,
					  TREE_TYPE (orig_len)))
	    orig_len = fold_convert (integer_type_node, orig_len);
	  repl = gimple_build_assign (gimple_call_lhs (stmt), orig_len);
	  gimple_seq_add_stmt_without_update (&stmts, repl);
	  gsi_replace_with_seq_vops (gsi, stmts);
	  /* gsi now points at the assignment to the lhs, get a
	     stmt iterator to the memcpy call.
	     ???  We can't use gsi_for_stmt as that doesn't work when the
	     CFG isn't built yet.  */
	  gimple_stmt_iterator gsi2 = *gsi;
	  gsi_prev (&gsi2);
	  fold_stmt (&gsi2);
	}
      else
	{
	  gsi_replace_with_seq_vops (gsi, stmts);
	  fold_stmt (gsi);
	}
      return true;
    }
  return false;
}

/* Fold a call to the {,v}fprintf{,_unlocked} and __{,v}printf_chk builtins.
   FP, FMT, and ARG are the arguments to the call.  We don't fold calls with
   more than 3 arguments, and ARG may be null in the 2-argument case.

   Return NULL_TREE if no simplification was possible, otherwise return the
   simplified form of the call as a tree.  FCODE is the BUILT_IN_*
   code of the function to be simplified.  */

static bool 
gimple_fold_builtin_fprintf (gimple_stmt_iterator *gsi,
			     tree fp, tree fmt, tree arg,
			     enum built_in_function fcode)
{
  gcall *stmt = as_a <gcall *> (gsi_stmt (*gsi));
  tree fn_fputc, fn_fputs;
  const char *fmt_str = NULL;

  /* If the return value is used, don't do the transformation.  */
  if (gimple_call_lhs (stmt) != NULL_TREE)
    return false;

  /* Check whether the format is a literal string constant.  */
  fmt_str = c_getstr (fmt);
  if (fmt_str == NULL)
    return false;

  if (fcode == BUILT_IN_FPRINTF_UNLOCKED)
    {
      /* If we're using an unlocked function, assume the other
	 unlocked functions exist explicitly.  */
      fn_fputc = builtin_decl_explicit (BUILT_IN_FPUTC_UNLOCKED);
      fn_fputs = builtin_decl_explicit (BUILT_IN_FPUTS_UNLOCKED);
    }
  else
    {
      fn_fputc = builtin_decl_implicit (BUILT_IN_FPUTC);
      fn_fputs = builtin_decl_implicit (BUILT_IN_FPUTS);
    }

  if (!init_target_chars ())
    return false;

  /* If the format doesn't contain % args or %%, use strcpy.  */
  if (strchr (fmt_str, target_percent) == NULL)
    {
      if (fcode != BUILT_IN_VFPRINTF && fcode != BUILT_IN_VFPRINTF_CHK
	  && arg)
	return false;

      /* If the format specifier was "", fprintf does nothing.  */
      if (fmt_str[0] == '\0')
	{
	  replace_call_with_value (gsi, NULL_TREE);
	  return true;
	}

      /* When "string" doesn't contain %, replace all cases of
	 fprintf (fp, string) with fputs (string, fp).  The fputs
	 builtin will take care of special cases like length == 1.  */
      if (fn_fputs)
	{
	  gcall *repl = gimple_build_call (fn_fputs, 2, fmt, fp);
	  replace_call_with_call_and_fold (gsi, repl);
	  return true;
	}
    }

  /* The other optimizations can be done only on the non-va_list variants.  */
  else if (fcode == BUILT_IN_VFPRINTF || fcode == BUILT_IN_VFPRINTF_CHK)
    return false;

  /* If the format specifier was "%s", call __builtin_fputs (arg, fp).  */
  else if (strcmp (fmt_str, target_percent_s) == 0)
    {
      if (!arg || ! POINTER_TYPE_P (TREE_TYPE (arg)))
	return false;
      if (fn_fputs)
	{
	  gcall *repl = gimple_build_call (fn_fputs, 2, arg, fp);
	  replace_call_with_call_and_fold (gsi, repl);
	  return true;
	}
    }

  /* If the format specifier was "%c", call __builtin_fputc (arg, fp).  */
  else if (strcmp (fmt_str, target_percent_c) == 0)
    {
      if (!arg
	  || ! useless_type_conversion_p (integer_type_node, TREE_TYPE (arg)))
	return false;
      if (fn_fputc)
	{
	  gcall *repl = gimple_build_call (fn_fputc, 2, arg, fp);
	  replace_call_with_call_and_fold (gsi, repl);
	  return true;
	}
    }

  return false;
}

/* Fold a call to the {,v}printf{,_unlocked} and __{,v}printf_chk builtins.
   FMT and ARG are the arguments to the call; we don't fold cases with
   more than 2 arguments, and ARG may be null if this is a 1-argument case.

   Return NULL_TREE if no simplification was possible, otherwise return the
   simplified form of the call as a tree.  FCODE is the BUILT_IN_*
   code of the function to be simplified.  */

static bool
gimple_fold_builtin_printf (gimple_stmt_iterator *gsi, tree fmt,
			    tree arg, enum built_in_function fcode)
{
  gcall *stmt = as_a <gcall *> (gsi_stmt (*gsi));
  tree fn_putchar, fn_puts, newarg;
  const char *fmt_str = NULL;

  /* If the return value is used, don't do the transformation.  */
  if (gimple_call_lhs (stmt) != NULL_TREE)
    return false;

  /* Check whether the format is a literal string constant.  */
  fmt_str = c_getstr (fmt);
  if (fmt_str == NULL)
    return false;

  if (fcode == BUILT_IN_PRINTF_UNLOCKED)
    {
      /* If we're using an unlocked function, assume the other
	 unlocked functions exist explicitly.  */
      fn_putchar = builtin_decl_explicit (BUILT_IN_PUTCHAR_UNLOCKED);
      fn_puts = builtin_decl_explicit (BUILT_IN_PUTS_UNLOCKED);
    }
  else
    {
      fn_putchar = builtin_decl_implicit (BUILT_IN_PUTCHAR);
      fn_puts = builtin_decl_implicit (BUILT_IN_PUTS);
    }

  if (!init_target_chars ())
    return false;

  if (strcmp (fmt_str, target_percent_s) == 0
      || strchr (fmt_str, target_percent) == NULL)
    {
      const char *str;

      if (strcmp (fmt_str, target_percent_s) == 0)
	{
	  if (fcode == BUILT_IN_VPRINTF || fcode == BUILT_IN_VPRINTF_CHK)
	    return false;

	  if (!arg || ! POINTER_TYPE_P (TREE_TYPE (arg)))
	    return false;

	  str = c_getstr (arg);
	  if (str == NULL)
	    return false;
	}
      else
	{
	  /* The format specifier doesn't contain any '%' characters.  */
	  if (fcode != BUILT_IN_VPRINTF && fcode != BUILT_IN_VPRINTF_CHK
	      && arg)
	    return false;
	  str = fmt_str;
	}

      /* If the string was "", printf does nothing.  */
      if (str[0] == '\0')
	{
	  replace_call_with_value (gsi, NULL_TREE);
	  return true;
	}

      /* If the string has length of 1, call putchar.  */
      if (str[1] == '\0')
	{
	  /* Given printf("c"), (where c is any one character,)
	     convert "c"[0] to an int and pass that to the replacement
	     function.  */
	  newarg = build_int_cst (integer_type_node, str[0]);
	  if (fn_putchar)
	    {
	      gcall *repl = gimple_build_call (fn_putchar, 1, newarg);
	      replace_call_with_call_and_fold (gsi, repl);
	      return true;
	    }
	}
      else
	{
	  /* If the string was "string\n", call puts("string").  */
	  size_t len = strlen (str);
	  if ((unsigned char)str[len - 1] == target_newline
	      && (size_t) (int) len == len
	      && (int) len > 0)
	    {
	      char *newstr;
	      tree offset_node, string_cst;

	      /* Create a NUL-terminated string that's one char shorter
		 than the original, stripping off the trailing '\n'.  */
	      newarg = build_string_literal (len, str);
	      string_cst = string_constant (newarg, &offset_node);
	      gcc_checking_assert (string_cst
				   && (TREE_STRING_LENGTH (string_cst)
				       == (int) len)
				   && integer_zerop (offset_node)
				   && (unsigned char)
				      TREE_STRING_POINTER (string_cst)[len - 1]
				      == target_newline);
	      /* build_string_literal creates a new STRING_CST,
		 modify it in place to avoid double copying.  */
	      newstr = CONST_CAST (char *, TREE_STRING_POINTER (string_cst));
	      newstr[len - 1] = '\0';
	      if (fn_puts)
		{
		  gcall *repl = gimple_build_call (fn_puts, 1, newarg);
		  replace_call_with_call_and_fold (gsi, repl);
		  return true;
		}
	    }
	  else
	    /* We'd like to arrange to call fputs(string,stdout) here,
	       but we need stdout and don't have a way to get it yet.  */
	    return false;
	}
    }

  /* The other optimizations can be done only on the non-va_list variants.  */
  else if (fcode == BUILT_IN_VPRINTF || fcode == BUILT_IN_VPRINTF_CHK)
    return false;

  /* If the format specifier was "%s\n", call __builtin_puts(arg).  */
  else if (strcmp (fmt_str, target_percent_s_newline) == 0)
    {
      if (!arg || ! POINTER_TYPE_P (TREE_TYPE (arg)))
	return false;
      if (fn_puts)
	{
	  gcall *repl = gimple_build_call (fn_puts, 1, arg);
	  replace_call_with_call_and_fold (gsi, repl);
	  return true;
	}
    }

  /* If the format specifier was "%c", call __builtin_putchar(arg).  */
  else if (strcmp (fmt_str, target_percent_c) == 0)
    {
      if (!arg || ! useless_type_conversion_p (integer_type_node,
					       TREE_TYPE (arg)))
	return false;
      if (fn_putchar)
	{
	  gcall *repl = gimple_build_call (fn_putchar, 1, arg);
	  replace_call_with_call_and_fold (gsi, repl);
	  return true;
	}
    }

  return false;
}



/* Fold a call to __builtin_strlen with known length LEN.  */

static bool
gimple_fold_builtin_strlen (gimple_stmt_iterator *gsi)
{
  gimple stmt = gsi_stmt (*gsi);
  tree len = get_maxval_strlen (gimple_call_arg (stmt, 0), 0);
  if (!len)
    return false;
  len = force_gimple_operand_gsi (gsi, len, true, NULL, true, GSI_SAME_STMT);
  replace_call_with_value (gsi, len);
  return true;
}


/* Fold the non-target builtin at *GSI and return whether any simplification
   was made.  */

static bool
gimple_fold_builtin (gimple_stmt_iterator *gsi)
{
  gcall *stmt = as_a <gcall *>(gsi_stmt (*gsi));
  tree callee = gimple_call_fndecl (stmt);

  /* Give up for always_inline inline builtins until they are
     inlined.  */
  if (avoid_folding_inline_builtin (callee))
    return false;

  unsigned n = gimple_call_num_args (stmt);
  enum built_in_function fcode = DECL_FUNCTION_CODE (callee);
  switch (fcode)
    {
    case BUILT_IN_BZERO:
      return gimple_fold_builtin_memset (gsi, integer_zero_node,
					 gimple_call_arg (stmt, 1));
    case BUILT_IN_MEMSET:
      return gimple_fold_builtin_memset (gsi,
					 gimple_call_arg (stmt, 1),
					 gimple_call_arg (stmt, 2));
    case BUILT_IN_BCOPY:
      return gimple_fold_builtin_memory_op (gsi, gimple_call_arg (stmt, 1),
					    gimple_call_arg (stmt, 0), 3);
    case BUILT_IN_MEMCPY:
      return gimple_fold_builtin_memory_op (gsi, gimple_call_arg (stmt, 0),
					    gimple_call_arg (stmt, 1), 0);
    case BUILT_IN_MEMPCPY:
      return gimple_fold_builtin_memory_op (gsi, gimple_call_arg (stmt, 0),
					    gimple_call_arg (stmt, 1), 1);
    case BUILT_IN_MEMMOVE:
      return gimple_fold_builtin_memory_op (gsi, gimple_call_arg (stmt, 0),
					    gimple_call_arg (stmt, 1), 3);
    case BUILT_IN_SPRINTF_CHK:
    case BUILT_IN_VSPRINTF_CHK:
      return gimple_fold_builtin_sprintf_chk (gsi, fcode);
    case BUILT_IN_STRCAT_CHK:
      return gimple_fold_builtin_strcat_chk (gsi);
    case BUILT_IN_STRNCAT_CHK:
      return gimple_fold_builtin_strncat_chk (gsi);
    case BUILT_IN_STRLEN:
      return gimple_fold_builtin_strlen (gsi);
    case BUILT_IN_STRCPY:
      return gimple_fold_builtin_strcpy (gsi,
					 gimple_call_arg (stmt, 0),
					 gimple_call_arg (stmt, 1));
    case BUILT_IN_STRNCPY:
      return gimple_fold_builtin_strncpy (gsi,
					  gimple_call_arg (stmt, 0),
					  gimple_call_arg (stmt, 1),
					  gimple_call_arg (stmt, 2));
    case BUILT_IN_STRCAT:
      return gimple_fold_builtin_strcat (gsi, gimple_call_arg (stmt, 0),
					 gimple_call_arg (stmt, 1));
    case BUILT_IN_STRNCAT:
      return gimple_fold_builtin_strncat (gsi);
    case BUILT_IN_FPUTS:
      return gimple_fold_builtin_fputs (gsi, gimple_call_arg (stmt, 0),
					gimple_call_arg (stmt, 1), false);
    case BUILT_IN_FPUTS_UNLOCKED:
      return gimple_fold_builtin_fputs (gsi, gimple_call_arg (stmt, 0),
					gimple_call_arg (stmt, 1), true);
    case BUILT_IN_MEMCPY_CHK:
    case BUILT_IN_MEMPCPY_CHK:
    case BUILT_IN_MEMMOVE_CHK:
    case BUILT_IN_MEMSET_CHK:
      return gimple_fold_builtin_memory_chk (gsi,
					     gimple_call_arg (stmt, 0),
					     gimple_call_arg (stmt, 1),
					     gimple_call_arg (stmt, 2),
					     gimple_call_arg (stmt, 3),
					     fcode);
    case BUILT_IN_STPCPY:
      return gimple_fold_builtin_stpcpy (gsi);
    case BUILT_IN_STRCPY_CHK:
    case BUILT_IN_STPCPY_CHK:
      return gimple_fold_builtin_stxcpy_chk (gsi,
					     gimple_call_arg (stmt, 0),
					     gimple_call_arg (stmt, 1),
					     gimple_call_arg (stmt, 2),
					     fcode);
    case BUILT_IN_STRNCPY_CHK:
    case BUILT_IN_STPNCPY_CHK:
      return gimple_fold_builtin_stxncpy_chk (gsi,
					      gimple_call_arg (stmt, 0),
					      gimple_call_arg (stmt, 1),
					      gimple_call_arg (stmt, 2),
					      gimple_call_arg (stmt, 3),
					      fcode);
    case BUILT_IN_SNPRINTF_CHK:
    case BUILT_IN_VSNPRINTF_CHK:
      return gimple_fold_builtin_snprintf_chk (gsi, fcode);
    case BUILT_IN_SNPRINTF:
      return gimple_fold_builtin_snprintf (gsi);
    case BUILT_IN_SPRINTF:
      return gimple_fold_builtin_sprintf (gsi);
    case BUILT_IN_FPRINTF:
    case BUILT_IN_FPRINTF_UNLOCKED:
    case BUILT_IN_VFPRINTF:
      if (n == 2 || n == 3)
	return gimple_fold_builtin_fprintf (gsi,
					    gimple_call_arg (stmt, 0),
					    gimple_call_arg (stmt, 1),
					    n == 3
					    ? gimple_call_arg (stmt, 2)
					    : NULL_TREE,
					    fcode);
      break;
    case BUILT_IN_FPRINTF_CHK:
    case BUILT_IN_VFPRINTF_CHK:
      if (n == 3 || n == 4)
	return gimple_fold_builtin_fprintf (gsi,
					    gimple_call_arg (stmt, 0),
					    gimple_call_arg (stmt, 2),
					    n == 4
					    ? gimple_call_arg (stmt, 3)
					    : NULL_TREE,
					    fcode);
      break;
    case BUILT_IN_PRINTF:
    case BUILT_IN_PRINTF_UNLOCKED:
    case BUILT_IN_VPRINTF:
      if (n == 1 || n == 2)
	return gimple_fold_builtin_printf (gsi, gimple_call_arg (stmt, 0),
					   n == 2
					   ? gimple_call_arg (stmt, 1)
					   : NULL_TREE, fcode);
      break;
    case BUILT_IN_PRINTF_CHK:
    case BUILT_IN_VPRINTF_CHK:
      if (n == 2 || n == 3)
	return gimple_fold_builtin_printf (gsi, gimple_call_arg (stmt, 1),
					   n == 3
					   ? gimple_call_arg (stmt, 2)
					   : NULL_TREE, fcode);
    default:;
    }

  /* Try the generic builtin folder.  */
  bool ignore = (gimple_call_lhs (stmt) == NULL);
  tree result = fold_call_stmt (stmt, ignore);
  if (result)
    {
      if (ignore)
	STRIP_NOPS (result);
      else
	result = fold_convert (gimple_call_return_type (stmt), result);
      if (!update_call_from_tree (gsi, result))
	gimplify_and_update_call_from_tree (gsi, result);
      return true;
    }

  return false;
}

/* Return true if ARG0 CODE ARG1 in infinite signed precision operation
   doesn't fit into TYPE.  The test for overflow should be regardless of
   -fwrapv, and even for unsigned types.  */

bool
arith_overflowed_p (enum tree_code code, const_tree type,
		    const_tree arg0, const_tree arg1)
{
  typedef FIXED_WIDE_INT (WIDE_INT_MAX_PRECISION * 2) widest2_int;
  typedef generic_wide_int <wi::extended_tree <WIDE_INT_MAX_PRECISION * 2> >
    widest2_int_cst;
  widest2_int warg0 = widest2_int_cst (arg0);
  widest2_int warg1 = widest2_int_cst (arg1);
  widest2_int wres;
  switch (code)
    {
    case PLUS_EXPR: wres = wi::add (warg0, warg1); break;
    case MINUS_EXPR: wres = wi::sub (warg0, warg1); break;
    case MULT_EXPR: wres = wi::mul (warg0, warg1); break;
    default: gcc_unreachable ();
    }
  signop sign = TYPE_SIGN (type);
  if (sign == UNSIGNED && wi::neg_p (wres))
    return true;
  return wi::min_precision (wres, sign) > TYPE_PRECISION (type);
}

/* Attempt to fold a call statement referenced by the statement iterator GSI.
   The statement may be replaced by another statement, e.g., if the call
   simplifies to a constant value. Return true if any changes were made.
   It is assumed that the operands have been previously folded.  */

static bool
gimple_fold_call (gimple_stmt_iterator *gsi, bool inplace)
{
  gcall *stmt = as_a <gcall *> (gsi_stmt (*gsi));
  tree callee;
  bool changed = false;
  unsigned i;

  /* Fold *& in call arguments.  */
  for (i = 0; i < gimple_call_num_args (stmt); ++i)
    if (REFERENCE_CLASS_P (gimple_call_arg (stmt, i)))
      {
	tree tmp = maybe_fold_reference (gimple_call_arg (stmt, i), false);
	if (tmp)
	  {
	    gimple_call_set_arg (stmt, i, tmp);
	    changed = true;
	  }
      }

  /* Check for virtual calls that became direct calls.  */
  callee = gimple_call_fn (stmt);
  if (callee && TREE_CODE (callee) == OBJ_TYPE_REF)
    {
      if (gimple_call_addr_fndecl (OBJ_TYPE_REF_EXPR (callee)) != NULL_TREE)
	{
          if (dump_file && virtual_method_call_p (callee)
	      && !possible_polymorphic_call_target_p
		    (callee, stmt, cgraph_node::get (gimple_call_addr_fndecl
						     (OBJ_TYPE_REF_EXPR (callee)))))
	    {
	      fprintf (dump_file,
		       "Type inheritance inconsistent devirtualization of ");
	      print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
	      fprintf (dump_file, " to ");
	      print_generic_expr (dump_file, callee, TDF_SLIM);
	      fprintf (dump_file, "\n");
	    }

	  gimple_call_set_fn (stmt, OBJ_TYPE_REF_EXPR (callee));
	  changed = true;
	}
      else if (flag_devirtualize && !inplace && virtual_method_call_p (callee))