2010-09-19 Basile Starynkevitch <basile@starynkevitch.net>

	MELT branch merged with trunk rev 164348, with some improvements
	in gcc/melt-runtime.[ch]

2010-09-19  Basile Starynkevitch  <basile@starynkevitch.net>
	[[merged with trunk rev.164348, so improved MELT runtime!]]
	* gcc/melt-runtime.h: improved comments.
	(melt_debug_garbcoll, melt_debuggc_eprintf):  Moved from melt-runtime.c.
	(melt_obmag_string): New declaration.
	(struct meltobject_st, struct meltclosure_st, struct
	meltroutine_st, struct meltmixbigint_st, struct meltstring_st):
	using GTY variable_size and @@MELTGTY@@ comment.
	(melt_mark_special): added debug print.

	* gcc/melt-runtime.c:  Improved comments.
	Include bversion.h, realmpfr.h, gimple-pretty-print.h.
	(ggc_force_collect) Declared external.
	(melt_forward_counter): Added.
	(melt_obmag_string): New function.
	(melt_alptr_1, melt_alptr_2, melt_break_alptr_1_at)
	(melt_break_alptr_2_at, melt_break_alptr_1,melt_break_alptr_1)
	(melt_allocate_young_gc_zone, melt_free_young_gc_zone): New.
	(delete_special, meltgc_make_special): Improved debug printf and
	use melt_break_alptr_1...
	(ggc_alloc_*) macros defined for backport to GCC 4.5
	(melt_forwarded_copy): Don't clear the new destination zone in old
	GGC heap.
	(meltgc_add_out_raw_len): Use ggc_alloc_atomic.
	(meltgc_raw_new_mappointers, meltgc_raw_put_mappointers)
	(meltgc_raw_remove_mappointers): Corrected length argument to
	ggc_alloc_cleared_vec_entrypointermelt_st.
	(melt_really_initialize): Call melt_allocate_young_gc_zone.
	(melt_initialize):  Set flag_plugin_added.
	(melt_val2passflag): TODO_verify_loops only in GCC 4.5




git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/melt-branch@164424 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 2670 insertions, 0 deletions

diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c
new file mode 100644
index 00000000000..d6e35807d05
--- /dev/null
+++ b/gcc/gimple-fold.c
@@ -0,0 +1,2670 @@
+/* Statement simplification on GIMPLE.
+   Copyright (C) 2010 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 "tree.h"
+#include "flags.h"
+#include "function.h"
+#include "tree-dump.h"
+#include "tree-flow.h"
+#include "tree-pass.h"
+#include "tree-ssa-propagate.h"
+#include "target.h"
+
+/* CVAL is value taken from DECL_INITIAL of variable.  Try to transorm it into
+   acceptable form for is_gimple_min_invariant.   */
+
+tree
+canonicalize_constructor_val (tree cval)
+{
+  STRIP_NOPS (cval);
+  if (TREE_CODE (cval) == POINTER_PLUS_EXPR)
+    {
+      tree t = maybe_fold_offset_to_address (EXPR_LOCATION (cval),
+					     TREE_OPERAND (cval, 0),
+					     TREE_OPERAND (cval, 1),
+					     TREE_TYPE (cval));
+      if (t)
+	cval = t;
+    }
+  if (TREE_CODE (cval) == ADDR_EXPR)
+    {
+      tree base = get_base_address (TREE_OPERAND (cval, 0));
+      if (base && TREE_CODE (base) == VAR_DECL)
+	add_referenced_var (base);
+    }
+  return 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)
+{
+  if ((TREE_STATIC (sym) || DECL_EXTERNAL (sym))
+      && (TREE_CODE (sym) == CONST_DECL
+	  || varpool_get_node (sym)->const_value_known))
+    {
+      tree val = DECL_INITIAL (sym);
+      if (val)
+	{
+	  val = canonicalize_constructor_val (val);
+	  if (is_gimple_min_invariant (val))
+	    return val;
+	}
+      /* Variables declared 'const' without an initializer
+	 have zero as the initializer if they may not be
+	 overridden at link or run time.  */
+      if (!val
+          && (INTEGRAL_TYPE_P (TREE_TYPE (sym))
+	       || SCALAR_FLOAT_TYPE_P (TREE_TYPE (sym))))
+	return fold_convert (TREE_TYPE (sym), integer_zero_node);
+    }
+
+  return NULL_TREE;
+}
+
+
+/* Return true if we may propagate the address expression ADDR into the
+   dereference DEREF and cancel them.  */
+
+bool
+may_propagate_address_into_dereference (tree addr, tree deref)
+{
+  gcc_assert (TREE_CODE (deref) == MEM_REF
+	      && TREE_CODE (addr) == ADDR_EXPR);
+
+  /* Don't propagate if ADDR's operand has incomplete type.  */
+  if (!COMPLETE_TYPE_P (TREE_TYPE (TREE_OPERAND (addr, 0))))
+    return false;
+
+  /* If the address is invariant then we do not need to preserve restrict
+     qualifications.  But we do need to preserve volatile qualifiers until
+     we can annotate the folded dereference itself properly.  */
+  if (is_gimple_min_invariant (addr)
+      && (!TREE_THIS_VOLATILE (deref)
+	  || TYPE_VOLATILE (TREE_TYPE (addr))))
+    return useless_type_conversion_p (TREE_TYPE (deref),
+				      TREE_TYPE (TREE_OPERAND (addr, 0)));
+
+  /* Else both the address substitution and the folding must result in
+     a valid useless type conversion sequence.  */
+  return (useless_type_conversion_p (TREE_TYPE (TREE_OPERAND (deref, 0)),
+				     TREE_TYPE (addr))
+	  && useless_type_conversion_p (TREE_TYPE (deref),
+					TREE_TYPE (TREE_OPERAND (addr, 0))));
+}
+
+
+/* A subroutine of fold_stmt.  Attempts to fold *(A+O) to A[X].
+   BASE is an array type.  OFFSET is a byte displacement.
+
+   LOC is the location of the original expression.  */
+
+static tree
+maybe_fold_offset_to_array_ref (location_t loc, tree base, tree offset)
+{
+  tree min_idx, idx, idx_type, elt_offset = integer_zero_node;
+  tree array_type, elt_type, elt_size;
+  tree domain_type;
+
+  /* If BASE is an ARRAY_REF, we can pick up another offset (this time
+     measured in units of the size of elements type) from that ARRAY_REF).
+     We can't do anything if either is variable.
+
+     The case we handle here is *(&A[N]+O).  */
+  if (TREE_CODE (base) == ARRAY_REF)
+    {
+      tree low_bound = array_ref_low_bound (base);
+
+      elt_offset = TREE_OPERAND (base, 1);
+      if (TREE_CODE (low_bound) != INTEGER_CST
+	  || TREE_CODE (elt_offset) != INTEGER_CST)
+	return NULL_TREE;
+
+      elt_offset = int_const_binop (MINUS_EXPR, elt_offset, low_bound, 0);
+      base = TREE_OPERAND (base, 0);
+    }
+
+  /* Ignore stupid user tricks of indexing non-array variables.  */
+  array_type = TREE_TYPE (base);
+  if (TREE_CODE (array_type) != ARRAY_TYPE)
+    return NULL_TREE;
+  elt_type = TREE_TYPE (array_type);
+
+  /* Use signed size type for intermediate computation on the index.  */
+  idx_type = ssizetype;
+
+  /* If OFFSET and ELT_OFFSET are zero, we don't care about the size of the
+     element type (so we can use the alignment if it's not constant).
+     Otherwise, compute the offset as an index by using a division.  If the
+     division isn't exact, then don't do anything.  */
+  elt_size = TYPE_SIZE_UNIT (elt_type);
+  if (!elt_size)
+    return NULL;
+  if (integer_zerop (offset))
+    {
+      if (TREE_CODE (elt_size) != INTEGER_CST)
+	elt_size = size_int (TYPE_ALIGN (elt_type));
+
+      idx = build_int_cst (idx_type, 0);
+    }
+  else
+    {
+      unsigned HOST_WIDE_INT lquo, lrem;
+      HOST_WIDE_INT hquo, hrem;
+      double_int soffset;
+
+      /* The final array offset should be signed, so we need
+	 to sign-extend the (possibly pointer) offset here
+	 and use signed division.  */
+      soffset = double_int_sext (tree_to_double_int (offset),
+				 TYPE_PRECISION (TREE_TYPE (offset)));
+      if (TREE_CODE (elt_size) != INTEGER_CST
+	  || div_and_round_double (TRUNC_DIV_EXPR, 0,
+				   soffset.low, soffset.high,
+				   TREE_INT_CST_LOW (elt_size),
+				   TREE_INT_CST_HIGH (elt_size),
+				   &lquo, &hquo, &lrem, &hrem)
+	  || lrem || hrem)
+	return NULL_TREE;
+
+      idx = build_int_cst_wide (idx_type, lquo, hquo);
+    }
+
+  /* Assume the low bound is zero.  If there is a domain type, get the
+     low bound, if any, convert the index into that type, and add the
+     low bound.  */
+  min_idx = build_int_cst (idx_type, 0);
+  domain_type = TYPE_DOMAIN (array_type);
+  if (domain_type)
+    {
+      idx_type = domain_type;
+      if (TYPE_MIN_VALUE (idx_type))
+	min_idx = TYPE_MIN_VALUE (idx_type);
+      else
+	min_idx = fold_convert (idx_type, min_idx);
+
+      if (TREE_CODE (min_idx) != INTEGER_CST)
+	return NULL_TREE;
+
+      elt_offset = fold_convert (idx_type, elt_offset);
+    }
+
+  if (!integer_zerop (min_idx))
+    idx = int_const_binop (PLUS_EXPR, idx, min_idx, 0);
+  if (!integer_zerop (elt_offset))
+    idx = int_const_binop (PLUS_EXPR, idx, elt_offset, 0);
+
+  /* Make sure to possibly truncate late after offsetting.  */
+  idx = fold_convert (idx_type, idx);
+
+  /* We don't want to construct access past array bounds. For example
+       char *(c[4]);
+       c[3][2];
+     should not be simplified into (*c)[14] or tree-vrp will
+     give false warnings.
+     This is only an issue for multi-dimensional arrays.  */
+  if (TREE_CODE (elt_type) == ARRAY_TYPE
+      && domain_type)
+    {
+      if (TYPE_MAX_VALUE (domain_type)
+	  && TREE_CODE (TYPE_MAX_VALUE (domain_type)) == INTEGER_CST
+	  && tree_int_cst_lt (TYPE_MAX_VALUE (domain_type), idx))
+	return NULL_TREE;
+      else if (TYPE_MIN_VALUE (domain_type)
+	       && TREE_CODE (TYPE_MIN_VALUE (domain_type)) == INTEGER_CST
+	       && tree_int_cst_lt (idx, TYPE_MIN_VALUE (domain_type)))
+	return NULL_TREE;
+      else if (compare_tree_int (idx, 0) < 0)
+	return NULL_TREE;
+    }
+
+  {
+    tree t = build4 (ARRAY_REF, elt_type, base, idx, NULL_TREE, NULL_TREE);
+    SET_EXPR_LOCATION (t, loc);
+    return t;
+  }
+}
+
+
+/* Attempt to express (ORIG_TYPE)BASE+OFFSET as BASE[index].
+   LOC is the location of original expression.
+
+   Before attempting the conversion strip off existing ADDR_EXPRs.  */
+
+tree
+maybe_fold_offset_to_reference (location_t loc, tree base, tree offset,
+				tree orig_type)
+{
+  tree ret;
+
+  STRIP_NOPS (base);
+  if (TREE_CODE (base) != ADDR_EXPR)
+    return NULL_TREE;
+
+  base = TREE_OPERAND (base, 0);
+  if (types_compatible_p (orig_type, TREE_TYPE (base))
+      && integer_zerop (offset))
+    return base;
+
+  ret = maybe_fold_offset_to_array_ref (loc, base, offset);
+  if (ret && types_compatible_p (orig_type, TREE_TYPE (ret)))
+    return ret;
+  return NULL_TREE;
+}
+
+/* Attempt to express (ORIG_TYPE)ADDR+OFFSET as (*ADDR)[index].
+   LOC is the location of the original expression.  */
+
+tree
+maybe_fold_offset_to_address (location_t loc, tree addr, tree offset,
+			      tree orig_type)
+{
+  tree base, ret;
+
+  STRIP_NOPS (addr);
+  if (TREE_CODE (addr) != ADDR_EXPR)
+    return NULL_TREE;
+  base = TREE_OPERAND (addr, 0);
+  ret = maybe_fold_offset_to_array_ref (loc, base, offset);
+  if (ret)
+    {
+      ret = build_fold_addr_expr (ret);
+      if (!useless_type_conversion_p (orig_type, TREE_TYPE (ret)))
+	return NULL_TREE;
+      SET_EXPR_LOCATION (ret, loc);
+    }
+
+  return ret;
+}
+
+
+/* A quaint feature extant in our address arithmetic is that there
+   can be hidden type changes here.  The type of the result need
+   not be the same as the type of the input pointer.
+
+   What we're after here is an expression of the form
+	(T *)(&array + const)
+   where array is OP0, const is OP1, RES_TYPE is T and
+   the cast doesn't actually exist, but is implicit in the
+   type of the POINTER_PLUS_EXPR.  We'd like to turn this into
+	&array[x]
+   which may be able to propagate further.  */
+
+tree
+maybe_fold_stmt_addition (location_t loc, tree res_type, tree op0, tree op1)
+{
+  tree ptd_type;
+  tree t;
+
+  /* The first operand should be an ADDR_EXPR.  */
+  if (TREE_CODE (op0) != ADDR_EXPR)
+    return NULL_TREE;
+  op0 = TREE_OPERAND (op0, 0);
+
+  /* It had better be a constant.  */
+  if (TREE_CODE (op1) != INTEGER_CST)
+    {
+      /* Or op0 should now be A[0] and the non-constant offset defined
+	 via a multiplication by the array element size.  */
+      if (TREE_CODE (op0) == ARRAY_REF
+	  /* As we will end up creating a variable index array access
+	     in the outermost array dimension make sure there isn't
+	     a more inner array that the index could overflow to.  */
+	  && TREE_CODE (TREE_OPERAND (op0, 0)) != ARRAY_REF
+	  && integer_zerop (TREE_OPERAND (op0, 1))
+	  && TREE_CODE (op1) == SSA_NAME)
+	{
+	  gimple offset_def = SSA_NAME_DEF_STMT (op1);
+	  tree elsz = TYPE_SIZE_UNIT (TREE_TYPE (op0));
+	  if (!host_integerp (elsz, 1)
+	      || !is_gimple_assign (offset_def))
+	    return NULL_TREE;
+
+	  /* Do not build array references of something that we can't
+	     see the true number of array dimensions for.  */
+	  if (!DECL_P (TREE_OPERAND (op0, 0))
+	      && !handled_component_p (TREE_OPERAND (op0, 0)))
+	    return NULL_TREE;
+
+	  if (gimple_assign_rhs_code (offset_def) == MULT_EXPR
+	      && TREE_CODE (gimple_assign_rhs2 (offset_def)) == INTEGER_CST
+	      && tree_int_cst_equal (gimple_assign_rhs2 (offset_def), elsz))
+	    return build_fold_addr_expr
+			  (build4 (ARRAY_REF, TREE_TYPE (op0),
+				   TREE_OPERAND (op0, 0),
+				   gimple_assign_rhs1 (offset_def),
+				   TREE_OPERAND (op0, 2),
+				   TREE_OPERAND (op0, 3)));
+	  else if (integer_onep (elsz)
+		   && gimple_assign_rhs_code (offset_def) != MULT_EXPR)
+	    return build_fold_addr_expr
+			  (build4 (ARRAY_REF, TREE_TYPE (op0),
+				   TREE_OPERAND (op0, 0),
+				   op1,
+				   TREE_OPERAND (op0, 2),
+				   TREE_OPERAND (op0, 3)));
+	}
+      else if (TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE
+	       /* Dto.  */
+	       && TREE_CODE (TREE_TYPE (TREE_TYPE (op0))) != ARRAY_TYPE
+	       && TREE_CODE (op1) == SSA_NAME)
+	{
+	  gimple offset_def = SSA_NAME_DEF_STMT (op1);
+	  tree elsz = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (op0)));
+	  if (!host_integerp (elsz, 1)
+	      || !is_gimple_assign (offset_def))
+	    return NULL_TREE;
+
+	  /* Do not build array references of something that we can't
+	     see the true number of array dimensions for.  */
+	  if (!DECL_P (op0)
+	      && !handled_component_p (op0))
+	    return NULL_TREE;
+
+	  if (gimple_assign_rhs_code (offset_def) == MULT_EXPR
+	      && TREE_CODE (gimple_assign_rhs2 (offset_def)) == INTEGER_CST
+	      && tree_int_cst_equal (gimple_assign_rhs2 (offset_def), elsz))
+	    return build_fold_addr_expr
+			  (build4 (ARRAY_REF, TREE_TYPE (TREE_TYPE (op0)),
+				   op0, gimple_assign_rhs1 (offset_def),
+				   integer_zero_node, NULL_TREE));
+	  else if (integer_onep (elsz)
+		   && gimple_assign_rhs_code (offset_def) != MULT_EXPR)
+	    return build_fold_addr_expr
+			  (build4 (ARRAY_REF, TREE_TYPE (TREE_TYPE (op0)),
+				   op0, op1,
+				   integer_zero_node, NULL_TREE));
+	}
+
+      return NULL_TREE;
+    }
+
+  /* If the first operand is an ARRAY_REF, expand it so that we can fold
+     the offset into it.  */
+  while (TREE_CODE (op0) == ARRAY_REF)
+    {
+      tree array_obj = TREE_OPERAND (op0, 0);
+      tree array_idx = TREE_OPERAND (op0, 1);
+      tree elt_type = TREE_TYPE (op0);
+      tree elt_size = TYPE_SIZE_UNIT (elt_type);
+      tree min_idx;
+
+      if (TREE_CODE (array_idx) != INTEGER_CST)
+	break;
+      if (TREE_CODE (elt_size) != INTEGER_CST)
+	break;
+
+      /* Un-bias the index by the min index of the array type.  */
+      min_idx = TYPE_DOMAIN (TREE_TYPE (array_obj));
+      if (min_idx)
+	{
+	  min_idx = TYPE_MIN_VALUE (min_idx);
+	  if (min_idx)
+	    {
+	      if (TREE_CODE (min_idx) != INTEGER_CST)
+		break;
+
+	      array_idx = fold_convert (TREE_TYPE (min_idx), array_idx);
+	      if (!integer_zerop (min_idx))
+		array_idx = int_const_binop (MINUS_EXPR, array_idx,
+					     min_idx, 0);
+	    }
+	}
+
+      /* Convert the index to a byte offset.  */
+      array_idx = fold_convert (sizetype, array_idx);
+      array_idx = int_const_binop (MULT_EXPR, array_idx, elt_size, 0);
+
+      /* Update the operands for the next round, or for folding.  */
+      op1 = int_const_binop (PLUS_EXPR,
+			     array_idx, op1, 0);
+      op0 = array_obj;
+    }
+
+  ptd_type = TREE_TYPE (res_type);
+  /* If we want a pointer to void, reconstruct the reference from the
+     array element type.  A pointer to that can be trivially converted
+     to void *.  This happens as we fold (void *)(ptr p+ off).  */
+  if (VOID_TYPE_P (ptd_type)
+      && TREE_CODE (TREE_TYPE (op0)) == ARRAY_TYPE)
+    ptd_type = TREE_TYPE (TREE_TYPE (op0));
+
+  /* At which point we can try some of the same things as for indirects.  */
+  t = maybe_fold_offset_to_array_ref (loc, op0, op1);
+  if (t)
+    {
+      t = build_fold_addr_expr (t);
+      if (!useless_type_conversion_p (res_type, TREE_TYPE (t)))
+	return NULL_TREE;
+      SET_EXPR_LOCATION (t, loc);
+    }
+
+  return t;
+}
+
+/* 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 *t = &expr;
+  tree result;
+
+  if (!is_lhs
+      && (result = fold_const_aggregate_ref (expr))
+      && is_gimple_min_invariant (result))
+    return result;
+
+  /* ???  We might want to open-code the relevant remaining cases
+     to avoid using the generic fold.  */
+  if (handled_component_p (*t)
+      && CONSTANT_CLASS_P (TREE_OPERAND (*t, 0)))
+    {
+      tree tem = fold (*t);
+      if (tem != *t)
+	return tem;
+    }
+
+  while (handled_component_p (*t))
+    t = &TREE_OPERAND (*t, 0);
+
+  /* Fold back MEM_REFs to reference trees.  */
+  if (TREE_CODE (*t) == MEM_REF
+      && TREE_CODE (TREE_OPERAND (*t, 0)) == ADDR_EXPR
+      && integer_zerop (TREE_OPERAND (*t, 1))
+      && (TREE_THIS_VOLATILE (*t)
+	  == TREE_THIS_VOLATILE (TREE_OPERAND (TREE_OPERAND (*t, 0), 0)))
+      && !TYPE_REF_CAN_ALIAS_ALL (TREE_TYPE (TREE_OPERAND (*t, 1)))
+      && (TYPE_MAIN_VARIANT (TREE_TYPE (*t))
+	  == TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (TREE_OPERAND (*t, 1)))))
+      /* We have to look out here to not drop a required conversion
+	 from the rhs to the lhs if is_lhs, but we don't have the
+	 rhs here to verify that.  Thus require strict type
+	 compatibility.  */
+      && types_compatible_p (TREE_TYPE (*t),
+			     TREE_TYPE (TREE_OPERAND
+					  (TREE_OPERAND (*t, 0), 0))))
+    {
+      tree tem;
+      *t = TREE_OPERAND (TREE_OPERAND (*t, 0), 0);
+      tem = maybe_fold_reference (expr, is_lhs);
+      if (tem)
+	return tem;
+      return expr;
+    }
+  /* Canonicalize MEM_REFs invariant address operand.  */
+  else if (TREE_CODE (*t) == MEM_REF
+	   && TREE_CODE (TREE_OPERAND (*t, 0)) == ADDR_EXPR
+	   && !DECL_P (TREE_OPERAND (TREE_OPERAND (*t, 0), 0))
+	   && !CONSTANT_CLASS_P (TREE_OPERAND (TREE_OPERAND (*t, 0), 0)))
+    {
+      tree tem = fold_binary (MEM_REF, TREE_TYPE (*t),
+			      TREE_OPERAND (*t, 0),
+			      TREE_OPERAND (*t, 1));
+      if (tem)
+	{
+	  *t = tem;
+	  tem = maybe_fold_reference (expr, is_lhs);
+	  if (tem)
+	    return tem;
+	  return expr;
+	}
+    }
+  else if (TREE_CODE (*t) == TARGET_MEM_REF)
+    {
+      tree tem = maybe_fold_tmr (*t);
+      if (tem)
+	{
+	  *t = tem;
+	  tem = maybe_fold_reference (expr, is_lhs);
+	  if (tem)
+	    return tem;
+	  return expr;
+	}
+    }
+  else if (!is_lhs
+	   && DECL_P (*t))
+    {
+      tree tem = get_symbol_constant_value (*t);
+      if (tem
+	  && useless_type_conversion_p (TREE_TYPE (*t), TREE_TYPE (tem)))
+	{
+	  *t = unshare_expr (tem);
+	  tem = maybe_fold_reference (expr, is_lhs);
+	  if (tem)
+	    return tem;
+	  return expr;
+	}
+    }
+
+  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);
+
+        /* Try to fold a conditional expression.  */
+        if (TREE_CODE (rhs) == COND_EXPR)
+          {
+	    tree op0 = COND_EXPR_COND (rhs);
+	    tree tem;
+	    bool set = false;
+	    location_t cond_loc = EXPR_LOCATION (rhs);
+
+	    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 (rhs), tem,
+				    COND_EXPR_THEN (rhs), COND_EXPR_ELSE (rhs));
+          }
+
+	else if (REFERENCE_CLASS_P (rhs))
+	  return maybe_fold_reference (rhs, false);
+
+	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 unshare_expr (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:
+      {
+	tree rhs = gimple_assign_rhs1 (stmt);
+
+	result = fold_unary_loc (loc, subcode, gimple_expr_type (stmt), rhs);
+	if (result)
+	  {
+	    /* If the operation was a conversion do _not_ mark a
+	       resulting constant with TREE_OVERFLOW if the original
+	       constant was not.  These conversions have implementation
+	       defined behavior and retaining the TREE_OVERFLOW flag
+	       here would confuse later passes such as VRP.  */
+	    if (CONVERT_EXPR_CODE_P (subcode)
+		&& TREE_CODE (result) == INTEGER_CST
+		&& TREE_CODE (rhs) == INTEGER_CST)
+	      TREE_OVERFLOW (result) = TREE_OVERFLOW (rhs);
+
+	    STRIP_USELESS_TYPE_CONVERSION (result);
+	    if (valid_gimple_rhs_p (result))
+	      return result;
+	  }
+	else if (CONVERT_EXPR_CODE_P (subcode)
+		 && POINTER_TYPE_P (gimple_expr_type (stmt))
+		 && POINTER_TYPE_P (TREE_TYPE (gimple_assign_rhs1 (stmt))))
+	  {
+	    tree type = gimple_expr_type (stmt);
+	    tree t = maybe_fold_offset_to_address (loc,
+						   gimple_assign_rhs1 (stmt),
+						   integer_zero_node, type);
+	    if (t)
+	      return t;
+	  }
+      }
+      break;
+
+    case GIMPLE_BINARY_RHS:
+      /* Try to fold pointer addition.  */
+      if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR)
+	{
+	  tree type = TREE_TYPE (gimple_assign_rhs1 (stmt));
+	  if (TREE_CODE (TREE_TYPE (type)) == ARRAY_TYPE)
+	    {
+	      type = build_pointer_type (TREE_TYPE (TREE_TYPE (type)));
+	      if (!useless_type_conversion_p
+		    (TREE_TYPE (gimple_assign_lhs (stmt)), type))
+		type = TREE_TYPE (gimple_assign_rhs1 (stmt));
+	    }
+	  result = maybe_fold_stmt_addition (gimple_location (stmt),
+					     type,
+					     gimple_assign_rhs1 (stmt),
+					     gimple_assign_rhs2 (stmt));
+	}
+
+      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;
+
+	  /* Fold might have produced non-GIMPLE, so if we trust it blindly
+	     we lose canonicalization opportunities.  Do not go again
+	     through fold here though, or the same non-GIMPLE will be
+	     produced.  */
+          if (commutative_tree_code (subcode)
+              && tree_swap_operands_p (gimple_assign_rhs1 (stmt),
+                                       gimple_assign_rhs2 (stmt), false))
+            return build2 (subcode, TREE_TYPE (gimple_assign_lhs (stmt)),
+                           gimple_assign_rhs2 (stmt),
+                           gimple_assign_rhs1 (stmt));
+        }
+      break;
+
+    case GIMPLE_TERNARY_RHS:
+      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;
+
+	  /* Fold might have produced non-GIMPLE, so if we trust it blindly
+	     we lose canonicalization opportunities.  Do not go again
+	     through fold here though, or the same non-GIMPLE will be
+	     produced.  */
+          if (commutative_ternary_tree_code (subcode)
+              && tree_swap_operands_p (gimple_assign_rhs1 (stmt),
+                                       gimple_assign_rhs2 (stmt), false))
+            return build3 (subcode, TREE_TYPE (gimple_assign_lhs (stmt)),
+			   gimple_assign_rhs2 (stmt),
+			   gimple_assign_rhs1 (stmt),
+			   gimple_assign_rhs3 (stmt));
+        }
+      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 (gimple 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;
+}
+
+/* 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;
+  tree tmp = NULL_TREE;  /* Silence warning.  */
+  gimple stmt, new_stmt;
+  gimple_stmt_iterator i;
+  gimple_seq stmts = gimple_seq_alloc();
+  struct gimplify_ctx gctx;
+  gimple last = NULL;
+  gimple laststore = NULL;
+  tree reaching_vuse;
+
+  stmt = gsi_stmt (*si_p);
+
+  gcc_assert (is_gimple_call (stmt));
+
+  lhs = gimple_call_lhs (stmt);
+  reaching_vuse = gimple_vuse (stmt);
+
+  push_gimplify_context (&gctx);
+
+  if (lhs == NULL_TREE)
+    gimplify_and_add (expr, &stmts);
+  else
+    tmp = get_initialized_tmp_var (expr, &stmts, NULL);
+
+  pop_gimplify_context (NULL);
+
+  if (gimple_has_location (stmt))
+    annotate_all_with_location (stmts, gimple_location (stmt));
+
+  /* The replacement can expose previously unreferenced variables.  */
+  for (i = gsi_start (stmts); !gsi_end_p (i); gsi_next (&i))
+    {
+      if (last)
+	{
+	  gsi_insert_before (si_p, last, GSI_NEW_STMT);
+	  gsi_next (si_p);
+	}
+      new_stmt = gsi_stmt (i);
+      if (gimple_in_ssa_p (cfun))
+	{
+	  find_new_referenced_vars (new_stmt);
+	  mark_symbols_for_renaming (new_stmt);
+	}
+      /* If the new statement has a VUSE, update it with exact SSA name we
+         know will reach this one.  */
+      if (gimple_vuse (new_stmt))
+	{
+	  /* If we've also seen a previous store create a new VDEF for
+	     the latter one, and make that the new reaching VUSE.  */
+	  if (laststore)
+	    {
+	      reaching_vuse = make_ssa_name (gimple_vop (cfun), laststore);
+	      gimple_set_vdef (laststore, reaching_vuse);
+	      update_stmt (laststore);
+	      laststore = NULL;
+	    }
+	  gimple_set_vuse (new_stmt, reaching_vuse);
+	  gimple_set_modified (new_stmt, true);
+	}
+      if (gimple_assign_single_p (new_stmt)
+	  && !is_gimple_reg (gimple_assign_lhs (new_stmt)))
+	{
+	  laststore = new_stmt;
+	}
+      last = new_stmt;
+    }
+
+  if (lhs == NULL_TREE)
+    {
+      /* If we replace a call without LHS that has a VDEF and our new
+         sequence ends with a store we must make that store have the same
+	 vdef in order not to break the sequencing.  This can happen
+	 for instance when folding memcpy calls into assignments.  */
+      if (gimple_vdef (stmt) && laststore)
+	{
+	  gimple_set_vdef (laststore, gimple_vdef (stmt));
+	  if (TREE_CODE (gimple_vdef (stmt)) == SSA_NAME)
+	    SSA_NAME_DEF_STMT (gimple_vdef (stmt)) = laststore;
+	  update_stmt (laststore);
+	}
+      else if (gimple_in_ssa_p (cfun))
+	{
+	  unlink_stmt_vdef (stmt);
+	  release_defs (stmt);
+	}
+      new_stmt = last;
+    }
+  else
+    {
+      if (last)
+	{
+	  gsi_insert_before (si_p, last, GSI_NEW_STMT);
+	  gsi_next (si_p);
+	}
+      if (laststore && is_gimple_reg (lhs))
+	{
+	  gimple_set_vdef (laststore, gimple_vdef (stmt));
+	  update_stmt (laststore);
+	  if (TREE_CODE (gimple_vdef (stmt)) == SSA_NAME)
+	    SSA_NAME_DEF_STMT (gimple_vdef (stmt)) = laststore;
+	  laststore = NULL;
+	}
+      else if (laststore)
+	{
+	  reaching_vuse = make_ssa_name (gimple_vop (cfun), laststore);
+	  gimple_set_vdef (laststore, reaching_vuse);
+	  update_stmt (laststore);
+	  laststore = NULL;
+	}
+      new_stmt = gimple_build_assign (lhs, tmp);
+      if (!is_gimple_reg (tmp))
+	gimple_set_vuse (new_stmt, reaching_vuse);
+      if (!is_gimple_reg (lhs))
+	{
+	  gimple_set_vdef (new_stmt, gimple_vdef (stmt));
+	  if (TREE_CODE (gimple_vdef (stmt)) == SSA_NAME)
+	    SSA_NAME_DEF_STMT (gimple_vdef (stmt)) = new_stmt;
+	}
+    }
+
+  gimple_set_location (new_stmt, gimple_location (stmt));
+  gsi_replace (si_p, new_stmt, false);
+}
+
+/* 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)
+    {
+      if (TREE_CODE (arg) == COND_EXPR)
+        return get_maxval_strlen (COND_EXPR_THEN (arg), length, visited, type)
+               && get_maxval_strlen (COND_EXPR_ELSE (arg), length, visited, type);
+      /* We can end up with &(*iftmp_1)[0] here as well, so handle it.  */
+      else 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 we were already here, break the infinite cycle.  */
+  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);
+          }
+        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;
+    }
+}
+
+
+/* Fold builtin call in statement STMT.  Returns a simplified tree.
+   We may return a non-constant expression, including another call
+   to a different function and with different arguments, e.g.,
+   substituting memcpy for strcpy when the string length is known.
+   Note that some builtins expand into inline code that may not
+   be valid in GIMPLE.  Callers must take care.  */
+
+tree
+gimple_fold_builtin (gimple stmt)
+{
+  tree result, val[3];
+  tree callee, a;
+  int arg_idx, type;
+  bitmap visited;
+  bool ignore;
+  int nargs;
+  location_t loc = gimple_location (stmt);
+
+  gcc_assert (is_gimple_call (stmt));
+
+  ignore = (gimple_call_lhs (stmt) == NULL);
+
+  /* First try the generic builtin folder.  If that succeeds, return the
+     result directly.  */
+  result = fold_call_stmt (stmt, ignore);
+  if (result)
+    {
+      if (ignore)
+	STRIP_NOPS (result);
+      return result;
+    }
+
+  /* Ignore MD builtins.  */
+  callee = gimple_call_fndecl (stmt);
+  if (DECL_BUILT_IN_CLASS (callee) == BUILT_IN_MD)
+    return NULL_TREE;
+
+  /* If the builtin could not be folded, and it has no argument list,
+     we're done.  */
+  nargs = gimple_call_num_args (stmt);
+  if (nargs == 0)
+    return NULL_TREE;
+
+  /* Limit the work only for builtins we know how to simplify.  */
+  switch (DECL_FUNCTION_CODE (callee))
+    {
+    case BUILT_IN_STRLEN:
+    case BUILT_IN_FPUTS:
+    case BUILT_IN_FPUTS_UNLOCKED:
+      arg_idx = 0;
+      type = 0;
+      break;
+    case BUILT_IN_STRCPY:
+    case BUILT_IN_STRNCPY:
+      arg_idx = 1;
+      type = 0;
+      break;
+    case BUILT_IN_MEMCPY_CHK:
+    case BUILT_IN_MEMPCPY_CHK:
+    case BUILT_IN_MEMMOVE_CHK:
+    case BUILT_IN_MEMSET_CHK:
+    case BUILT_IN_STRNCPY_CHK:
+      arg_idx = 2;
+      type = 2;
+      break;
+    case BUILT_IN_STRCPY_CHK:
+    case BUILT_IN_STPCPY_CHK:
+      arg_idx = 1;
+      type = 1;
+      break;
+    case BUILT_IN_SNPRINTF_CHK:
+    case BUILT_IN_VSNPRINTF_CHK:
+      arg_idx = 1;
+      type = 2;
+      break;
+    default:
+      return NULL_TREE;
+    }
+
+  if (arg_idx >= nargs)
+    return NULL_TREE;
+
+  /* Try to use the dataflow information gathered by the CCP process.  */
+  visited = BITMAP_ALLOC (NULL);
+  bitmap_clear (visited);
+
+  memset (val, 0, sizeof (val));
+  a = gimple_call_arg (stmt, arg_idx);
+  if (!get_maxval_strlen (a, &val[arg_idx], visited, type))
+    val[arg_idx] = NULL_TREE;
+
+  BITMAP_FREE (visited);
+
+  result = NULL_TREE;
+  switch (DECL_FUNCTION_CODE (callee))
+    {
+    case BUILT_IN_STRLEN:
+      if (val[0] && nargs == 1)
+	{
+	  tree new_val =
+              fold_convert (TREE_TYPE (gimple_call_lhs (stmt)), val[0]);
+
+	  /* If the result is not a valid gimple value, or not a cast
+	     of a valid gimple value, then we cannot use the result.  */
+	  if (is_gimple_val (new_val)
+	      || (is_gimple_cast (new_val)
+		  && is_gimple_val (TREE_OPERAND (new_val, 0))))
+	    return new_val;
+	}
+      break;
+
+    case BUILT_IN_STRCPY:
+      if (val[1] && is_gimple_val (val[1]) && nargs == 2)
+	result = fold_builtin_strcpy (loc, callee,
+                                      gimple_call_arg (stmt, 0),
+                                      gimple_call_arg (stmt, 1),
+				      val[1]);
+      break;
+
+    case BUILT_IN_STRNCPY:
+      if (val[1] && is_gimple_val (val[1]) && nargs == 3)
+	result = fold_builtin_strncpy (loc, callee,
+                                       gimple_call_arg (stmt, 0),
+                                       gimple_call_arg (stmt, 1),
+                                       gimple_call_arg (stmt, 2),
+				       val[1]);
+      break;
+
+    case BUILT_IN_FPUTS:
+      if (nargs == 2)
+	result = fold_builtin_fputs (loc, gimple_call_arg (stmt, 0),
+				     gimple_call_arg (stmt, 1),
+				     ignore, false, val[0]);
+      break;
+
+    case BUILT_IN_FPUTS_UNLOCKED:
+      if (nargs == 2)
+	result = fold_builtin_fputs (loc, gimple_call_arg (stmt, 0),
+				     gimple_call_arg (stmt, 1),
+				     ignore, true, val[0]);
+      break;
+
+    case BUILT_IN_MEMCPY_CHK:
+    case BUILT_IN_MEMPCPY_CHK:
+    case BUILT_IN_MEMMOVE_CHK:
+    case BUILT_IN_MEMSET_CHK:
+      if (val[2] && is_gimple_val (val[2]) && nargs == 4)
+	result = fold_builtin_memory_chk (loc, callee,
+                                          gimple_call_arg (stmt, 0),
+                                          gimple_call_arg (stmt, 1),
+                                          gimple_call_arg (stmt, 2),
+                                          gimple_call_arg (stmt, 3),
+					  val[2], ignore,
+					  DECL_FUNCTION_CODE (callee));
+      break;
+
+    case BUILT_IN_STRCPY_CHK:
+    case BUILT_IN_STPCPY_CHK:
+      if (val[1] && is_gimple_val (val[1]) && nargs == 3)
+	result = fold_builtin_stxcpy_chk (loc, callee,
+                                          gimple_call_arg (stmt, 0),
+                                          gimple_call_arg (stmt, 1),
+                                          gimple_call_arg (stmt, 2),
+					  val[1], ignore,
+					  DECL_FUNCTION_CODE (callee));
+      break;
+
+    case BUILT_IN_STRNCPY_CHK:
+      if (val[2] && is_gimple_val (val[2]) && nargs == 4)
+	result = fold_builtin_strncpy_chk (loc, gimple_call_arg (stmt, 0),
+                                           gimple_call_arg (stmt, 1),
+                                           gimple_call_arg (stmt, 2),
+                                           gimple_call_arg (stmt, 3),
+					   val[2]);
+      break;
+
+    case BUILT_IN_SNPRINTF_CHK:
+    case BUILT_IN_VSNPRINTF_CHK:
+      if (val[1] && is_gimple_val (val[1]))
+	result = gimple_fold_builtin_snprintf_chk (stmt, val[1],
+                                                   DECL_FUNCTION_CODE (callee));
+      break;
+
+    default:
+      gcc_unreachable ();
+    }
+
+  if (result && ignore)
+    result = fold_ignored_result (result);
+  return result;
+}
+
+/* Return the first of the base binfos of BINFO that has virtual functions.  */
+
+static tree
+get_first_base_binfo_with_virtuals (tree binfo)
+{
+  int i;
+  tree base_binfo;
+
+  for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
+    if (BINFO_VIRTUALS (base_binfo))
+      return base_binfo;
+
+  return NULL_TREE;
+}
+
+
+/* Search for a base binfo of BINFO that corresponds to TYPE and return it if
+   it is found or NULL_TREE if it is not.  */
+
+static tree
+get_base_binfo_for_type (tree binfo, tree type)
+{
+  int i;
+  tree base_binfo;
+  tree res = NULL_TREE;
+
+  for (i = 0; BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
+    if (TREE_TYPE (base_binfo) == type)
+      {
+	gcc_assert (!res);
+	res = base_binfo;
+      }
+
+  return res;
+}
+
+/* Return a binfo describing the part of object referenced by expression REF.
+   Return NULL_TREE if it cannot be determined.  REF can consist of a series of
+   COMPONENT_REFs of a declaration or of an INDIRECT_REF or it can also be just
+   a simple declaration, indirect reference or an SSA_NAME.  If the function
+   discovers an INDIRECT_REF or an SSA_NAME, it will assume that the
+   encapsulating type is described by KNOWN_BINFO, if it is not NULL_TREE.
+   Otherwise the first non-artificial field declaration or the base declaration
+   will be examined to get the encapsulating type. */
+
+tree
+gimple_get_relevant_ref_binfo (tree ref, tree known_binfo)
+{
+  while (true)
+    {
+      if (TREE_CODE (ref) == COMPONENT_REF)
+	{
+	  tree par_type;
+	  tree binfo, base_binfo;
+	  tree field = TREE_OPERAND (ref, 1);
+
+	  if (!DECL_ARTIFICIAL (field))
+	    {
+	      tree type = TREE_TYPE (field);
+	      if (TREE_CODE (type) == RECORD_TYPE)
+		return TYPE_BINFO (type);
+	      else
+		return NULL_TREE;
+	    }
+
+	  par_type = TREE_TYPE (TREE_OPERAND (ref, 0));
+	  binfo = TYPE_BINFO (par_type);
+	  if (!binfo
+	      || BINFO_N_BASE_BINFOS (binfo) == 0)
+	    return NULL_TREE;
+
+	  base_binfo = get_first_base_binfo_with_virtuals (binfo);
+	  if (base_binfo && BINFO_TYPE (base_binfo) != TREE_TYPE (field))
+	    {
+	      tree d_binfo;
+
+	      d_binfo = gimple_get_relevant_ref_binfo (TREE_OPERAND (ref, 0),
+						       known_binfo);
+	      /* Get descendant binfo. */
+	      if (!d_binfo)
+		return NULL_TREE;
+	      return get_base_binfo_for_type (d_binfo, TREE_TYPE (field));
+	    }
+
+	  ref = TREE_OPERAND (ref, 0);
+	}
+      else if (DECL_P (ref) && TREE_CODE (TREE_TYPE (ref)) == RECORD_TYPE)
+	return TYPE_BINFO (TREE_TYPE (ref));
+      else if (known_binfo
+	       && (TREE_CODE (ref) == SSA_NAME
+		   || TREE_CODE (ref) == MEM_REF))
+	return known_binfo;
+      else
+	return NULL_TREE;
+    }
+}
+
+/* Fold a OBJ_TYPE_REF expression to the address of a function. TOKEN is
+   integer form of OBJ_TYPE_REF_TOKEN of the reference expression.  KNOWN_BINFO
+   carries the binfo describing the true type of OBJ_TYPE_REF_OBJECT(REF).  */
+
+tree
+gimple_fold_obj_type_ref_known_binfo (HOST_WIDE_INT token, tree known_binfo)
+{
+  HOST_WIDE_INT i;
+  tree v, fndecl;
+  struct cgraph_node *node;
+
+  v = BINFO_VIRTUALS (known_binfo);
+  i = 0;
+  while (i != token)
+    {
+      i += (TARGET_VTABLE_USES_DESCRIPTORS
+	    ? TARGET_VTABLE_USES_DESCRIPTORS : 1);
+      v = TREE_CHAIN (v);
+    }
+
+  fndecl = TREE_VALUE (v);
+  node = cgraph_get_node (fndecl);
+  /* When cgraph node is missing and function is not public, we cannot
+     devirtualize.  This can happen in WHOPR when the actual method
+     ends up in other partition, because we found devirtualization
+     possibility too late.  */
+  if ((!node || (!node->analyzed && !node->in_other_partition))
+      && (!TREE_PUBLIC (fndecl) || DECL_COMDAT (fndecl)))
+    return NULL;
+  return build_fold_addr_expr (fndecl);
+}
+
+
+/* Fold a OBJ_TYPE_REF expression to the address of a function.  If KNOWN_TYPE
+   is not NULL_TREE, it is the true type of the outmost encapsulating object if
+   that comes from a pointer SSA_NAME.  If the true outmost encapsulating type
+   can be determined from a declaration OBJ_TYPE_REF_OBJECT(REF), it is used
+   regardless of KNOWN_TYPE (which thus can be NULL_TREE).  */
+
+tree
+gimple_fold_obj_type_ref (tree ref, tree known_type)
+{
+  tree obj = OBJ_TYPE_REF_OBJECT (ref);
+  tree known_binfo = known_type ? TYPE_BINFO (known_type) : NULL_TREE;
+  tree binfo;
+
+  if (TREE_CODE (obj) == ADDR_EXPR)
+    obj = TREE_OPERAND (obj, 0);
+
+  binfo = gimple_get_relevant_ref_binfo (obj, known_binfo);
+  if (binfo)
+    {
+      HOST_WIDE_INT token = tree_low_cst (OBJ_TYPE_REF_TOKEN (ref), 1);
+      return gimple_fold_obj_type_ref_known_binfo (token, binfo);
+    }
+  else
+    return NULL_TREE;
+}
+
+/* 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
+fold_gimple_call (gimple_stmt_iterator *gsi)
+{
+  gimple stmt = gsi_stmt (*gsi);
+
+  tree callee = gimple_call_fndecl (stmt);
+
+  /* Check for builtins that CCP can handle using information not
+     available in the generic fold routines.  */
+  if (callee && DECL_BUILT_IN (callee))
+    {
+      tree result = gimple_fold_builtin (stmt);
+
+      if (result)
+	{
+          if (!update_call_from_tree (gsi, result))
+	    gimplify_and_update_call_from_tree (gsi, result);
+	  return true;
+	}
+    }
+  else
+    {
+      /* ??? Should perhaps do this in fold proper.  However, doing it
+         there requires that we create a new CALL_EXPR, and that requires
+         copying EH region info to the new node.  Easier to just do it
+         here where we can just smash the call operand.  */
+      /* ??? Is there a good reason not to do this in fold_stmt_inplace?  */
+      callee = gimple_call_fn (stmt);
+      if (TREE_CODE (callee) == OBJ_TYPE_REF
+          && TREE_CODE (OBJ_TYPE_REF_OBJECT (callee)) == ADDR_EXPR)
+        {
+          tree t;
+
+          t = gimple_fold_obj_type_ref (callee, NULL_TREE);
+          if (t)
+            {
+              gimple_call_set_fn (stmt, t);
+              return true;
+            }
+        }
+    }
+
+  return false;
+}
+
+/* Worker for both fold_stmt and fold_stmt_inplace.  The INPLACE argument
+   distinguishes both cases.  */
+
+static bool
+fold_stmt_1 (gimple_stmt_iterator *gsi, bool inplace)
+{
+  bool changed = false;
+  gimple stmt = gsi_stmt (*gsi);
+  unsigned i;
+
+  /* Fold the main computation performed by the statement.  */
+  switch (gimple_code (stmt))
+    {
+    case GIMPLE_ASSIGN:
+      {
+	unsigned old_num_ops = gimple_num_ops (stmt);
+	tree new_rhs = fold_gimple_assign (gsi);
+	tree lhs = gimple_assign_lhs (stmt);
+	if (new_rhs
+	    && !useless_type_conversion_p (TREE_TYPE (lhs),
+					   TREE_TYPE (new_rhs)))
+	  new_rhs = fold_convert (TREE_TYPE (lhs), new_rhs);
+	if (new_rhs
+	    && (!inplace
+		|| get_gimple_rhs_num_ops (TREE_CODE (new_rhs)) < old_num_ops))
+	  {
+	    gimple_assign_set_rhs_from_tree (gsi, new_rhs);
+	    changed = true;
+	  }
+	break;
+      }
+
+    case GIMPLE_COND:
+      changed |= fold_gimple_cond (stmt);
+      break;
+
+    case GIMPLE_CALL:
+      /* 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;
+	      }
+	  }
+      /* The entire statement may be replaced in this case.  */
+      if (!inplace)
+	changed |= fold_gimple_call (gsi);
+      break;
+
+    case GIMPLE_ASM:
+      /* Fold *& in asm operands.  */
+      for (i = 0; i < gimple_asm_noutputs (stmt); ++i)
+	{
+	  tree link = gimple_asm_output_op (stmt, i);
+	  tree op = TREE_VALUE (link);
+	  if (REFERENCE_CLASS_P (op)
+	      && (op = maybe_fold_reference (op, true)) != NULL_TREE)
+	    {
+	      TREE_VALUE (link) = op;
+	      changed = true;
+	    }
+	}
+      for (i = 0; i < gimple_asm_ninputs (stmt); ++i)
+	{
+	  tree link = gimple_asm_input_op (stmt, i);
+	  tree op = TREE_VALUE (link);
+	  if (REFERENCE_CLASS_P (op)
+	      && (op = maybe_fold_reference (op, false)) != NULL_TREE)
+	    {
+	      TREE_VALUE (link) = op;
+	      changed = true;
+	    }
+	}
+      break;
+
+    case GIMPLE_DEBUG:
+      if (gimple_debug_bind_p (stmt))
+	{
+	  tree val = gimple_debug_bind_get_value (stmt);
+	  if (val
+	      && REFERENCE_CLASS_P (val))
+	    {
+	      tree tem = maybe_fold_reference (val, false);
+	      if (tem)
+		{
+		  gimple_debug_bind_set_value (stmt, tem);
+		  changed = true;
+		}
+	    }
+	}
+      break;
+
+    default:;
+    }
+
+  stmt = gsi_stmt (*gsi);
+
+  /* Fold *& on the lhs.  */
+  if (gimple_has_lhs (stmt))
+    {
+      tree lhs = gimple_get_lhs (stmt);
+      if (lhs && REFERENCE_CLASS_P (lhs))
+	{
+	  tree new_lhs = maybe_fold_reference (lhs, true);
+	  if (new_lhs)
+	    {
+	      gimple_set_lhs (stmt, new_lhs);
+	      changed = true;
+	    }
+	}
+    }
+
+  return changed;
+}
+
+/* Fold the statement pointed to by GSI.  In some cases, this function may
+   replace the whole statement with a new one.  Returns true iff folding
+   makes any changes.
+   The statement pointed to by GSI should be in valid gimple form but may
+   be in unfolded state as resulting from for example constant propagation
+   which can produce *&x = 0.  */
+
+bool
+fold_stmt (gimple_stmt_iterator *gsi)
+{
+  return fold_stmt_1 (gsi, false);
+}
+
+/* Perform the minimal folding on statement STMT.  Only operations like
+   *&x created by constant propagation are handled.  The statement cannot
+   be replaced with a new one.  Return true if the statement was
+   changed, false otherwise.
+   The statement STMT should be in valid gimple form but may
+   be in unfolded state as resulting from for example constant propagation
+   which can produce *&x = 0.  */
+
+bool
+fold_stmt_inplace (gimple stmt)
+{
+  gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
+  bool changed = fold_stmt_1 (&gsi, true);
+  gcc_assert (gsi_stmt (gsi) == stmt);
+  return changed;
+}
+
+/* Canonicalize and possibly invert the boolean EXPR; return NULL_TREE 
+   if EXPR is null or we don't know how.
+   If non-null, the result always has boolean type.  */
+
+static tree
+canonicalize_bool (tree expr, bool invert)
+{
+  if (!expr)
+    return NULL_TREE;
+  else if (invert)
+    {
+      if (integer_nonzerop (expr))
+	return boolean_false_node;
+      else if (integer_zerop (expr))
+	return boolean_true_node;
+      else if (TREE_CODE (expr) == SSA_NAME)
+	return fold_build2 (EQ_EXPR, boolean_type_node, expr,
+			    build_int_cst (TREE_TYPE (expr), 0));
+      else if (TREE_CODE_CLASS (TREE_CODE (expr)) == tcc_comparison)
+	return fold_build2 (invert_tree_comparison (TREE_CODE (expr), false),
+			    boolean_type_node,
+			    TREE_OPERAND (expr, 0),
+			    TREE_OPERAND (expr, 1));
+      else
+	return NULL_TREE;
+    }
+  else
+    {
+      if (TREE_CODE (TREE_TYPE (expr)) == BOOLEAN_TYPE)
+	return expr;
+      if (integer_nonzerop (expr))
+	return boolean_true_node;
+      else if (integer_zerop (expr))
+	return boolean_false_node;
+      else if (TREE_CODE (expr) == SSA_NAME)
+	return fold_build2 (NE_EXPR, boolean_type_node, expr,
+			    build_int_cst (TREE_TYPE (expr), 0));
+      else if (TREE_CODE_CLASS (TREE_CODE (expr)) == tcc_comparison)
+	return fold_build2 (TREE_CODE (expr),
+			    boolean_type_node,
+			    TREE_OPERAND (expr, 0),
+			    TREE_OPERAND (expr, 1));
+      else
+	return NULL_TREE;
+    }
+}
+
+/* Check to see if a boolean expression EXPR is logically equivalent to the
+   comparison (OP1 CODE OP2).  Check for various identities involving
+   SSA_NAMEs.  */
+
+static bool
+same_bool_comparison_p (const_tree expr, enum tree_code code,
+			const_tree op1, const_tree op2)
+{
+  gimple s;
+
+  /* The obvious case.  */
+  if (TREE_CODE (expr) == code
+      && operand_equal_p (TREE_OPERAND (expr, 0), op1, 0)
+      && operand_equal_p (TREE_OPERAND (expr, 1), op2, 0))
+    return true;
+
+  /* Check for comparing (name, name != 0) and the case where expr
+     is an SSA_NAME with a definition matching the comparison.  */
+  if (TREE_CODE (expr) == SSA_NAME
+      && TREE_CODE (TREE_TYPE (expr)) == BOOLEAN_TYPE)
+    {
+      if (operand_equal_p (expr, op1, 0))
+	return ((code == NE_EXPR && integer_zerop (op2))
+		|| (code == EQ_EXPR && integer_nonzerop (op2)));
+      s = SSA_NAME_DEF_STMT (expr);
+      if (is_gimple_assign (s)
+	  && gimple_assign_rhs_code (s) == code
+	  && operand_equal_p (gimple_assign_rhs1 (s), op1, 0)
+	  && operand_equal_p (gimple_assign_rhs2 (s), op2, 0))
+	return true;
+    }
+
+  /* If op1 is of the form (name != 0) or (name == 0), and the definition
+     of name is a comparison, recurse.  */
+  if (TREE_CODE (op1) == SSA_NAME
+      && TREE_CODE (TREE_TYPE (op1)) == BOOLEAN_TYPE)
+    {
+      s = SSA_NAME_DEF_STMT (op1);
+      if (is_gimple_assign (s)
+	  && TREE_CODE_CLASS (gimple_assign_rhs_code (s)) == tcc_comparison)
+	{
+	  enum tree_code c = gimple_assign_rhs_code (s);
+	  if ((c == NE_EXPR && integer_zerop (op2))
+	      || (c == EQ_EXPR && integer_nonzerop (op2)))
+	    return same_bool_comparison_p (expr, c,
+					   gimple_assign_rhs1 (s),
+					   gimple_assign_rhs2 (s));
+	  if ((c == EQ_EXPR && integer_zerop (op2))
+	      || (c == NE_EXPR && integer_nonzerop (op2)))
+	    return same_bool_comparison_p (expr,
+					   invert_tree_comparison (c, false),
+					   gimple_assign_rhs1 (s),
+					   gimple_assign_rhs2 (s));
+	}
+    }
+  return false;
+}
+
+/* Check to see if two boolean expressions OP1 and OP2 are logically
+   equivalent.  */
+
+static bool
+same_bool_result_p (const_tree op1, const_tree op2)
+{
+  /* Simple cases first.  */
+  if (operand_equal_p (op1, op2, 0))
+    return true;
+
+  /* Check the cases where at least one of the operands is a comparison.
+     These are a bit smarter than operand_equal_p in that they apply some
+     identifies on SSA_NAMEs.  */
+  if (TREE_CODE_CLASS (TREE_CODE (op2)) == tcc_comparison
+      && same_bool_comparison_p (op1, TREE_CODE (op2),
+				 TREE_OPERAND (op2, 0),
+				 TREE_OPERAND (op2, 1)))
+    return true;
+  if (TREE_CODE_CLASS (TREE_CODE (op1)) == tcc_comparison
+      && same_bool_comparison_p (op2, TREE_CODE (op1),
+				 TREE_OPERAND (op1, 0),
+				 TREE_OPERAND (op1, 1)))
+    return true;
+
+  /* Default case.  */
+  return false;
+}
+
+/* Forward declarations for some mutually recursive functions.  */
+
+static tree
+and_comparisons_1 (enum tree_code code1, tree op1a, tree op1b,
+		   enum tree_code code2, tree op2a, tree op2b);
+static tree
+and_var_with_comparison (tree var, bool invert,
+			 enum tree_code code2, tree op2a, tree op2b);
+static tree
+and_var_with_comparison_1 (gimple stmt, 
+			   enum tree_code code2, tree op2a, tree op2b);
+static tree
+or_comparisons_1 (enum tree_code code1, tree op1a, tree op1b,
+		  enum tree_code code2, tree op2a, tree op2b);
+static tree
+or_var_with_comparison (tree var, bool invert,
+			enum tree_code code2, tree op2a, tree op2b);
+static tree
+or_var_with_comparison_1 (gimple stmt, 
+			  enum tree_code code2, tree op2a, tree op2b);
+
+/* Helper function for and_comparisons_1:  try to simplify the AND of the
+   ssa variable VAR with the comparison specified by (OP2A CODE2 OP2B).
+   If INVERT is true, invert the value of the VAR before doing the AND.
+   Return NULL_EXPR if we can't simplify this to a single expression.  */
+
+static tree
+and_var_with_comparison (tree var, bool invert,
+			 enum tree_code code2, tree op2a, tree op2b)
+{
+  tree t;
+  gimple stmt = SSA_NAME_DEF_STMT (var);
+
+  /* We can only deal with variables whose definitions are assignments.  */
+  if (!is_gimple_assign (stmt))
+    return NULL_TREE;
+  
+  /* If we have an inverted comparison, apply DeMorgan's law and rewrite
+     !var AND (op2a code2 op2b) => !(var OR !(op2a code2 op2b))
+     Then we only have to consider the simpler non-inverted cases.  */
+  if (invert)
+    t = or_var_with_comparison_1 (stmt, 
+				  invert_tree_comparison (code2, false),
+				  op2a, op2b);
+  else
+    t = and_var_with_comparison_1 (stmt, code2, op2a, op2b);
+  return canonicalize_bool (t, invert);
+}
+
+/* Try to simplify the AND of the ssa variable defined by the assignment
+   STMT with the comparison specified by (OP2A CODE2 OP2B).
+   Return NULL_EXPR if we can't simplify this to a single expression.  */
+
+static tree
+and_var_with_comparison_1 (gimple stmt,
+			   enum tree_code code2, tree op2a, tree op2b)
+{
+  tree var = gimple_assign_lhs (stmt);
+  tree true_test_var = NULL_TREE;
+  tree false_test_var = NULL_TREE;
+  enum tree_code innercode = gimple_assign_rhs_code (stmt);
+
+  /* Check for identities like (var AND (var == 0)) => false.  */
+  if (TREE_CODE (op2a) == SSA_NAME
+      && TREE_CODE (TREE_TYPE (var)) == BOOLEAN_TYPE)
+    {
+      if ((code2 == NE_EXPR && integer_zerop (op2b))
+	  || (code2 == EQ_EXPR && integer_nonzerop (op2b)))
+	{
+	  true_test_var = op2a;
+	  if (var == true_test_var)
+	    return var;
+	}
+      else if ((code2 == EQ_EXPR && integer_zerop (op2b))
+	       || (code2 == NE_EXPR && integer_nonzerop (op2b)))
+	{
+	  false_test_var = op2a;
+	  if (var == false_test_var)
+	    return boolean_false_node;
+	}
+    }
+
+  /* If the definition is a comparison, recurse on it.  */
+  if (TREE_CODE_CLASS (innercode) == tcc_comparison)
+    {
+      tree t = and_comparisons_1 (innercode,
+				  gimple_assign_rhs1 (stmt),
+				  gimple_assign_rhs2 (stmt),
+				  code2,
+				  op2a,
+				  op2b);
+      if (t)
+	return t;
+    }
+
+  /* If the definition is an AND or OR expression, we may be able to
+     simplify by reassociating.  */
+  if (innercode == TRUTH_AND_EXPR
+      || innercode == TRUTH_OR_EXPR
+      || (TREE_CODE (TREE_TYPE (var)) == BOOLEAN_TYPE
+	  && (innercode == BIT_AND_EXPR || innercode == BIT_IOR_EXPR)))
+    {
+      tree inner1 = gimple_assign_rhs1 (stmt);
+      tree inner2 = gimple_assign_rhs2 (stmt);
+      gimple s;
+      tree t;
+      tree partial = NULL_TREE;
+      bool is_and = (innercode == TRUTH_AND_EXPR || innercode == BIT_AND_EXPR);
+      
+      /* Check for boolean identities that don't require recursive examination
+	 of inner1/inner2:
+	 inner1 AND (inner1 AND inner2) => inner1 AND inner2 => var
+	 inner1 AND (inner1 OR inner2) => inner1
+	 !inner1 AND (inner1 AND inner2) => false
+	 !inner1 AND (inner1 OR inner2) => !inner1 AND inner2
+         Likewise for similar cases involving inner2.  */
+      if (inner1 == true_test_var)
+	return (is_and ? var : inner1);
+      else if (inner2 == true_test_var)
+	return (is_and ? var : inner2);
+      else if (inner1 == false_test_var)
+	return (is_and
+		? boolean_false_node
+		: and_var_with_comparison (inner2, false, code2, op2a, op2b));
+      else if (inner2 == false_test_var)
+	return (is_and
+		? boolean_false_node
+		: and_var_with_comparison (inner1, false, code2, op2a, op2b));
+
+      /* Next, redistribute/reassociate the AND across the inner tests.
+	 Compute the first partial result, (inner1 AND (op2a code op2b))  */
+      if (TREE_CODE (inner1) == SSA_NAME
+	  && is_gimple_assign (s = SSA_NAME_DEF_STMT (inner1))
+	  && TREE_CODE_CLASS (gimple_assign_rhs_code (s)) == tcc_comparison
+	  && (t = maybe_fold_and_comparisons (gimple_assign_rhs_code (s),
+					      gimple_assign_rhs1 (s),
+					      gimple_assign_rhs2 (s),
+					      code2, op2a, op2b)))
+	{
+	  /* Handle the AND case, where we are reassociating:
+	     (inner1 AND inner2) AND (op2a code2 op2b)
+	     => (t AND inner2)
+	     If the partial result t is a constant, we win.  Otherwise
+	     continue on to try reassociating with the other inner test.  */
+	  if (is_and)
+	    {
+	      if (integer_onep (t))
+		return inner2;
+	      else if (integer_zerop (t))
+		return boolean_false_node;
+	    }
+
+	  /* Handle the OR case, where we are redistributing:
+	     (inner1 OR inner2) AND (op2a code2 op2b)
+	     => (t OR (inner2 AND (op2a code2 op2b)))  */
+	  else
+	    {
+	      if (integer_onep (t))
+		return boolean_true_node;
+	      else
+		/* Save partial result for later.  */
+		partial = t;
+	    }
+	}
+      
+      /* Compute the second partial result, (inner2 AND (op2a code op2b)) */
+      if (TREE_CODE (inner2) == SSA_NAME
+	  && is_gimple_assign (s = SSA_NAME_DEF_STMT (inner2))
+	  && TREE_CODE_CLASS (gimple_assign_rhs_code (s)) == tcc_comparison
+	  && (t = maybe_fold_and_comparisons (gimple_assign_rhs_code (s),
+					      gimple_assign_rhs1 (s),
+					      gimple_assign_rhs2 (s),
+					      code2, op2a, op2b)))
+	{
+	  /* Handle the AND case, where we are reassociating:
+	     (inner1 AND inner2) AND (op2a code2 op2b)
+	     => (inner1 AND t)  */
+	  if (is_and)
+	    {
+	      if (integer_onep (t))
+		return inner1;
+	      else if (integer_zerop (t))
+		return boolean_false_node;
+	    }
+
+	  /* Handle the OR case. where we are redistributing:
+	     (inner1 OR inner2) AND (op2a code2 op2b)
+	     => (t OR (inner1 AND (op2a code2 op2b)))
+	     => (t OR partial)  */
+	  else
+	    {
+	      if (integer_onep (t))
+		return boolean_true_node;
+	      else if (partial)
+		{
+		  /* We already got a simplification for the other
+		     operand to the redistributed OR expression.  The
+		     interesting case is when at least one is false.
+		     Or, if both are the same, we can apply the identity
+		     (x OR x) == x.  */
+		  if (integer_zerop (partial))
+		    return t;
+		  else if (integer_zerop (t))
+		    return partial;
+		  else if (same_bool_result_p (t, partial))
+		    return t;
+		}
+	    }
+	}
+    }
+  return NULL_TREE;
+}
+
+/* Try to simplify the AND of two comparisons defined by
+   (OP1A CODE1 OP1B) and (OP2A CODE2 OP2B), respectively.
+   If this can be done without constructing an intermediate value,
+   return the resulting tree; otherwise NULL_TREE is returned.
+   This function is deliberately asymmetric as it recurses on SSA_DEFs
+   in the first comparison but not the second.  */
+
+static tree
+and_comparisons_1 (enum tree_code code1, tree op1a, tree op1b,
+		   enum tree_code code2, tree op2a, tree op2b)
+{
+  /* First check for ((x CODE1 y) AND (x CODE2 y)).  */
+  if (operand_equal_p (op1a, op2a, 0)
+      && operand_equal_p (op1b, op2b, 0))
+    {
+      tree t = combine_comparisons (UNKNOWN_LOCATION,
+				    TRUTH_ANDIF_EXPR, code1, code2,
+				    boolean_type_node, op1a, op1b);
+      if (t)
+	return t;
+    }
+
+  /* Likewise the swapped case of the above.  */
+  if (operand_equal_p (op1a, op2b, 0)
+      && operand_equal_p (op1b, op2a, 0))
+    {
+      tree t = combine_comparisons (UNKNOWN_LOCATION,
+				    TRUTH_ANDIF_EXPR, code1,
+				    swap_tree_comparison (code2),
+				    boolean_type_node, op1a, op1b);
+      if (t)
+	return t;
+    }
+
+  /* If both comparisons are of the same value against constants, we might
+     be able to merge them.  */
+  if (operand_equal_p (op1a, op2a, 0)
+      && TREE_CODE (op1b) == INTEGER_CST
+      && TREE_CODE (op2b) == INTEGER_CST)
+    {
+      int cmp = tree_int_cst_compare (op1b, op2b);
+
+      /* If we have (op1a == op1b), we should either be able to
+	 return that or FALSE, depending on whether the constant op1b
+	 also satisfies the other comparison against op2b.  */
+      if (code1 == EQ_EXPR)
+	{
+	  bool done = true;
+	  bool val;
+	  switch (code2)
+	    {
+	    case EQ_EXPR: val = (cmp == 0); break;
+	    case NE_EXPR: val = (cmp != 0); break;
+	    case LT_EXPR: val = (cmp < 0); break;
+	    case GT_EXPR: val = (cmp > 0); break;
+	    case LE_EXPR: val = (cmp <= 0); break;
+	    case GE_EXPR: val = (cmp >= 0); break;
+	    default: done = false;
+	    }
+	  if (done)
+	    {
+	      if (val)
+		return fold_build2 (code1, boolean_type_node, op1a, op1b);
+	      else
+		return boolean_false_node;
+	    }
+	}
+      /* Likewise if the second comparison is an == comparison.  */
+      else if (code2 == EQ_EXPR)
+	{
+	  bool done = true;
+	  bool val;
+	  switch (code1)
+	    {
+	    case EQ_EXPR: val = (cmp == 0); break;
+	    case NE_EXPR: val = (cmp != 0); break;
+	    case LT_EXPR: val = (cmp > 0); break;
+	    case GT_EXPR: val = (cmp < 0); break;
+	    case LE_EXPR: val = (cmp >= 0); break;
+	    case GE_EXPR: val = (cmp <= 0); break;
+	    default: done = false;
+	    }
+	  if (done)
+	    {
+	      if (val)
+		return fold_build2 (code2, boolean_type_node, op2a, op2b);
+	      else
+		return boolean_false_node;
+	    }
+	}
+
+      /* Same business with inequality tests.  */
+      else if (code1 == NE_EXPR)
+	{
+	  bool val;
+	  switch (code2)
+	    {
+	    case EQ_EXPR: val = (cmp != 0); break;
+	    case NE_EXPR: val = (cmp == 0); break;
+	    case LT_EXPR: val = (cmp >= 0); break;
+	    case GT_EXPR: val = (cmp <= 0); break;
+	    case LE_EXPR: val = (cmp > 0); break;
+	    case GE_EXPR: val = (cmp < 0); break;
+	    default:
+	      val = false;
+	    }
+	  if (val)
+	    return fold_build2 (code2, boolean_type_node, op2a, op2b);
+	}
+      else if (code2 == NE_EXPR)
+	{
+	  bool val;
+	  switch (code1)
+	    {
+	    case EQ_EXPR: val = (cmp == 0); break;
+	    case NE_EXPR: val = (cmp != 0); break;
+	    case LT_EXPR: val = (cmp <= 0); break;
+	    case GT_EXPR: val = (cmp >= 0); break;
+	    case LE_EXPR: val = (cmp < 0); break;
+	    case GE_EXPR: val = (cmp > 0); break;
+	    default:
+	      val = false;
+	    }
+	  if (val)
+	    return fold_build2 (code1, boolean_type_node, op1a, op1b);
+	}
+
+      /* Chose the more restrictive of two < or <= comparisons.  */
+      else if ((code1 == LT_EXPR || code1 == LE_EXPR)
+	       && (code2 == LT_EXPR || code2 == LE_EXPR))
+	{
+	  if ((cmp < 0) || (cmp == 0 && code1 == LT_EXPR))
+	    return fold_build2 (code1, boolean_type_node, op1a, op1b);
+	  else
+	    return fold_build2 (code2, boolean_type_node, op2a, op2b);
+	}
+
+      /* Likewise chose the more restrictive of two > or >= comparisons.  */
+      else if ((code1 == GT_EXPR || code1 == GE_EXPR)
+	       && (code2 == GT_EXPR || code2 == GE_EXPR))
+	{
+	  if ((cmp > 0) || (cmp == 0 && code1 == GT_EXPR))
+	    return fold_build2 (code1, boolean_type_node, op1a, op1b);
+	  else
+	    return fold_build2 (code2, boolean_type_node, op2a, op2b);
+	}
+
+      /* Check for singleton ranges.  */
+      else if (cmp == 0
+	       && ((code1 == LE_EXPR && code2 == GE_EXPR)
+		   || (code1 == GE_EXPR && code2 == LE_EXPR)))
+	return fold_build2 (EQ_EXPR, boolean_type_node, op1a, op2b);
+
+      /* Check for disjoint ranges. */
+      else if (cmp <= 0
+	       && (code1 == LT_EXPR || code1 == LE_EXPR)
+	       && (code2 == GT_EXPR || code2 == GE_EXPR))
+	return boolean_false_node;
+      else if (cmp >= 0
+	       && (code1 == GT_EXPR || code1 == GE_EXPR)
+	       && (code2 == LT_EXPR || code2 == LE_EXPR))
+	return boolean_false_node;
+    }
+
+  /* Perhaps the first comparison is (NAME != 0) or (NAME == 1) where
+     NAME's definition is a truth value.  See if there are any simplifications
+     that can be done against the NAME's definition.  */
+  if (TREE_CODE (op1a) == SSA_NAME
+      && (code1 == NE_EXPR || code1 == EQ_EXPR)
+      && (integer_zerop (op1b) || integer_onep (op1b)))
+    {
+      bool invert = ((code1 == EQ_EXPR && integer_zerop (op1b))
+		     || (code1 == NE_EXPR && integer_onep (op1b)));
+      gimple stmt = SSA_NAME_DEF_STMT (op1a);
+      switch (gimple_code (stmt))
+	{
+	case GIMPLE_ASSIGN:
+	  /* Try to simplify by copy-propagating the definition.  */
+	  return and_var_with_comparison (op1a, invert, code2, op2a, op2b);
+
+	case GIMPLE_PHI:
+	  /* If every argument to the PHI produces the same result when
+	     ANDed with the second comparison, we win.
+	     Do not do this unless the type is bool since we need a bool
+	     result here anyway.  */
+	  if (TREE_CODE (TREE_TYPE (op1a)) == BOOLEAN_TYPE)
+	    {
+	      tree result = NULL_TREE;
+	      unsigned i;
+	      for (i = 0; i < gimple_phi_num_args (stmt); i++)
+		{
+		  tree arg = gimple_phi_arg_def (stmt, i);
+		  
+		  /* If this PHI has itself as an argument, ignore it.
+		     If all the other args produce the same result,
+		     we're still OK.  */
+		  if (arg == gimple_phi_result (stmt))
+		    continue;
+		  else if (TREE_CODE (arg) == INTEGER_CST)
+		    {
+		      if (invert ? integer_nonzerop (arg) : integer_zerop (arg))
+			{
+			  if (!result)
+			    result = boolean_false_node;
+			  else if (!integer_zerop (result))
+			    return NULL_TREE;
+			}
+		      else if (!result)
+			result = fold_build2 (code2, boolean_type_node,
+					      op2a, op2b);
+		      else if (!same_bool_comparison_p (result,
+							code2, op2a, op2b))
+			return NULL_TREE;
+		    }
+		  else if (TREE_CODE (arg) == SSA_NAME)
+		    {
+		      tree temp = and_var_with_comparison (arg, invert,
+							   code2, op2a, op2b);
+		      if (!temp)
+			return NULL_TREE;
+		      else if (!result)
+			result = temp;
+		      else if (!same_bool_result_p (result, temp))
+			return NULL_TREE;
+		    }
+		  else
+		    return NULL_TREE;
+		}
+	      return result;
+	    }
+
+	default:
+	  break;
+	}
+    }
+  return NULL_TREE;
+}
+
+/* Try to simplify the AND of two comparisons, specified by
+   (OP1A CODE1 OP1B) and (OP2B CODE2 OP2B), respectively.
+   If this can be simplified to a single expression (without requiring
+   introducing more SSA variables to hold intermediate values),
+   return the resulting tree.  Otherwise return NULL_TREE.
+   If the result expression is non-null, it has boolean type.  */
+
+tree
+maybe_fold_and_comparisons (enum tree_code code1, tree op1a, tree op1b,
+			    enum tree_code code2, tree op2a, tree op2b)
+{
+  tree t = and_comparisons_1 (code1, op1a, op1b, code2, op2a, op2b);
+  if (t)
+    return t;
+  else
+    return and_comparisons_1 (code2, op2a, op2b, code1, op1a, op1b);
+}
+
+/* Helper function for or_comparisons_1:  try to simplify the OR of the
+   ssa variable VAR with the comparison specified by (OP2A CODE2 OP2B).
+   If INVERT is true, invert the value of VAR before doing the OR.
+   Return NULL_EXPR if we can't simplify this to a single expression.  */
+
+static tree
+or_var_with_comparison (tree var, bool invert,
+			enum tree_code code2, tree op2a, tree op2b)
+{
+  tree t;
+  gimple stmt = SSA_NAME_DEF_STMT (var);
+
+  /* We can only deal with variables whose definitions are assignments.  */
+  if (!is_gimple_assign (stmt))
+    return NULL_TREE;
+  
+  /* If we have an inverted comparison, apply DeMorgan's law and rewrite
+     !var OR (op2a code2 op2b) => !(var AND !(op2a code2 op2b))
+     Then we only have to consider the simpler non-inverted cases.  */
+  if (invert)
+    t = and_var_with_comparison_1 (stmt, 
+				   invert_tree_comparison (code2, false),
+				   op2a, op2b);
+  else
+    t = or_var_with_comparison_1 (stmt, code2, op2a, op2b);
+  return canonicalize_bool (t, invert);
+}
+
+/* Try to simplify the OR of the ssa variable defined by the assignment
+   STMT with the comparison specified by (OP2A CODE2 OP2B).
+   Return NULL_EXPR if we can't simplify this to a single expression.  */
+
+static tree
+or_var_with_comparison_1 (gimple stmt,
+			  enum tree_code code2, tree op2a, tree op2b)
+{
+  tree var = gimple_assign_lhs (stmt);
+  tree true_test_var = NULL_TREE;
+  tree false_test_var = NULL_TREE;
+  enum tree_code innercode = gimple_assign_rhs_code (stmt);
+
+  /* Check for identities like (var OR (var != 0)) => true .  */
+  if (TREE_CODE (op2a) == SSA_NAME
+      && TREE_CODE (TREE_TYPE (var)) == BOOLEAN_TYPE)
+    {
+      if ((code2 == NE_EXPR && integer_zerop (op2b))
+	  || (code2 == EQ_EXPR && integer_nonzerop (op2b)))
+	{
+	  true_test_var = op2a;
+	  if (var == true_test_var)
+	    return var;
+	}
+      else if ((code2 == EQ_EXPR && integer_zerop (op2b))
+	       || (code2 == NE_EXPR && integer_nonzerop (op2b)))
+	{
+	  false_test_var = op2a;
+	  if (var == false_test_var)
+	    return boolean_true_node;
+	}
+    }
+
+  /* If the definition is a comparison, recurse on it.  */
+  if (TREE_CODE_CLASS (innercode) == tcc_comparison)
+    {
+      tree t = or_comparisons_1 (innercode,
+				 gimple_assign_rhs1 (stmt),
+				 gimple_assign_rhs2 (stmt),
+				 code2,
+				 op2a,
+				 op2b);
+      if (t)
+	return t;
+    }
+  
+  /* If the definition is an AND or OR expression, we may be able to
+     simplify by reassociating.  */
+  if (innercode == TRUTH_AND_EXPR
+      || innercode == TRUTH_OR_EXPR
+      || (TREE_CODE (TREE_TYPE (var)) == BOOLEAN_TYPE
+	  && (innercode == BIT_AND_EXPR || innercode == BIT_IOR_EXPR)))
+    {
+      tree inner1 = gimple_assign_rhs1 (stmt);
+      tree inner2 = gimple_assign_rhs2 (stmt);
+      gimple s;
+      tree t;
+      tree partial = NULL_TREE;
+      bool is_or = (innercode == TRUTH_OR_EXPR || innercode == BIT_IOR_EXPR);
+      
+      /* Check for boolean identities that don't require recursive examination
+	 of inner1/inner2:
+	 inner1 OR (inner1 OR inner2) => inner1 OR inner2 => var
+	 inner1 OR (inner1 AND inner2) => inner1
+	 !inner1 OR (inner1 OR inner2) => true
+	 !inner1 OR (inner1 AND inner2) => !inner1 OR inner2
+      */
+      if (inner1 == true_test_var)
+	return (is_or ? var : inner1);
+      else if (inner2 == true_test_var)
+	return (is_or ? var : inner2);
+      else if (inner1 == false_test_var)
+	return (is_or
+		? boolean_true_node
+		: or_var_with_comparison (inner2, false, code2, op2a, op2b));
+      else if (inner2 == false_test_var)
+	return (is_or
+		? boolean_true_node
+		: or_var_with_comparison (inner1, false, code2, op2a, op2b));
+      
+      /* Next, redistribute/reassociate the OR across the inner tests.
+	 Compute the first partial result, (inner1 OR (op2a code op2b))  */
+      if (TREE_CODE (inner1) == SSA_NAME
+	  && is_gimple_assign (s = SSA_NAME_DEF_STMT (inner1))
+	  && TREE_CODE_CLASS (gimple_assign_rhs_code (s)) == tcc_comparison
+	  && (t = maybe_fold_or_comparisons (gimple_assign_rhs_code (s),
+					     gimple_assign_rhs1 (s),
+					     gimple_assign_rhs2 (s),
+					     code2, op2a, op2b)))
+	{
+	  /* Handle the OR case, where we are reassociating:
+	     (inner1 OR inner2) OR (op2a code2 op2b)
+	     => (t OR inner2)
+	     If the partial result t is a constant, we win.  Otherwise
+	     continue on to try reassociating with the other inner test.  */
+	  if (innercode == TRUTH_OR_EXPR)
+	    {
+	      if (integer_onep (t))
+		return boolean_true_node;
+	      else if (integer_zerop (t))
+		return inner2;
+	    }
+	  
+	  /* Handle the AND case, where we are redistributing:
+	     (inner1 AND inner2) OR (op2a code2 op2b)
+	     => (t AND (inner2 OR (op2a code op2b)))  */
+	  else
+	    {
+	      if (integer_zerop (t))
+		return boolean_false_node;
+	      else
+		/* Save partial result for later.  */
+		partial = t;
+	    }
+	}
+      
+      /* Compute the second partial result, (inner2 OR (op2a code op2b)) */
+      if (TREE_CODE (inner2) == SSA_NAME
+	  && is_gimple_assign (s = SSA_NAME_DEF_STMT (inner2))
+	  && TREE_CODE_CLASS (gimple_assign_rhs_code (s)) == tcc_comparison
+	  && (t = maybe_fold_or_comparisons (gimple_assign_rhs_code (s),
+					     gimple_assign_rhs1 (s),
+					     gimple_assign_rhs2 (s),
+					     code2, op2a, op2b)))
+	{
+	  /* Handle the OR case, where we are reassociating:
+	     (inner1 OR inner2) OR (op2a code2 op2b)
+	     => (inner1 OR t)  */
+	  if (innercode == TRUTH_OR_EXPR)
+	    {
+	      if (integer_zerop (t))
+		return inner1;
+	      else if (integer_onep (t))
+		return boolean_true_node;
+	    }
+	  
+	  /* Handle the AND case, where we are redistributing:
+	     (inner1 AND inner2) OR (op2a code2 op2b)
+	     => (t AND (inner1 OR (op2a code2 op2b)))
+	     => (t AND partial)  */
+	  else 
+	    {
+	      if (integer_zerop (t))
+		return boolean_false_node;
+	      else if (partial)
+		{
+		  /* We already got a simplification for the other
+		     operand to the redistributed AND expression.  The
+		     interesting case is when at least one is true.
+		     Or, if both are the same, we can apply the identity
+		     (x AND x) == true.  */
+		  if (integer_onep (partial))
+		    return t;
+		  else if (integer_onep (t))
+		    return partial;
+		  else if (same_bool_result_p (t, partial))
+		    return boolean_true_node;
+		}
+	    }
+	}
+    }
+  return NULL_TREE;
+}
+
+/* Try to simplify the OR of two comparisons defined by
+   (OP1A CODE1 OP1B) and (OP2A CODE2 OP2B), respectively.
+   If this can be done without constructing an intermediate value,
+   return the resulting tree; otherwise NULL_TREE is returned.
+   This function is deliberately asymmetric as it recurses on SSA_DEFs
+   in the first comparison but not the second.  */
+
+static tree
+or_comparisons_1 (enum tree_code code1, tree op1a, tree op1b,
+		  enum tree_code code2, tree op2a, tree op2b)
+{
+  /* First check for ((x CODE1 y) OR (x CODE2 y)).  */
+  if (operand_equal_p (op1a, op2a, 0)
+      && operand_equal_p (op1b, op2b, 0))
+    {
+      tree t = combine_comparisons (UNKNOWN_LOCATION,
+				    TRUTH_ORIF_EXPR, code1, code2,
+				    boolean_type_node, op1a, op1b);
+      if (t)
+	return t;
+    }
+
+  /* Likewise the swapped case of the above.  */
+  if (operand_equal_p (op1a, op2b, 0)
+      && operand_equal_p (op1b, op2a, 0))
+    {
+      tree t = combine_comparisons (UNKNOWN_LOCATION,
+				    TRUTH_ORIF_EXPR, code1,
+				    swap_tree_comparison (code2),
+				    boolean_type_node, op1a, op1b);
+      if (t)
+	return t;
+    }
+
+  /* If both comparisons are of the same value against constants, we might
+     be able to merge them.  */
+  if (operand_equal_p (op1a, op2a, 0)
+      && TREE_CODE (op1b) == INTEGER_CST
+      && TREE_CODE (op2b) == INTEGER_CST)
+    {
+      int cmp = tree_int_cst_compare (op1b, op2b);
+
+      /* If we have (op1a != op1b), we should either be able to
+	 return that or TRUE, depending on whether the constant op1b
+	 also satisfies the other comparison against op2b.  */
+      if (code1 == NE_EXPR)
+	{
+	  bool done = true;
+	  bool val;
+	  switch (code2)
+	    {
+	    case EQ_EXPR: val = (cmp == 0); break;
+	    case NE_EXPR: val = (cmp != 0); break;
+	    case LT_EXPR: val = (cmp < 0); break;
+	    case GT_EXPR: val = (cmp > 0); break;
+	    case LE_EXPR: val = (cmp <= 0); break;
+	    case GE_EXPR: val = (cmp >= 0); break;
+	    default: done = false;
+	    }
+	  if (done)
+	    {
+	      if (val)
+		return boolean_true_node;
+	      else
+		return fold_build2 (code1, boolean_type_node, op1a, op1b);
+	    }
+	}
+      /* Likewise if the second comparison is a != comparison.  */
+      else if (code2 == NE_EXPR)
+	{
+	  bool done = true;
+	  bool val;
+	  switch (code1)
+	    {
+	    case EQ_EXPR: val = (cmp == 0); break;
+	    case NE_EXPR: val = (cmp != 0); break;
+	    case LT_EXPR: val = (cmp > 0); break;
+	    case GT_EXPR: val = (cmp < 0); break;
+	    case LE_EXPR: val = (cmp >= 0); break;
+	    case GE_EXPR: val = (cmp <= 0); break;
+	    default: done = false;
+	    }
+	  if (done)
+	    {
+	      if (val)
+		return boolean_true_node;
+	      else
+		return fold_build2 (code2, boolean_type_node, op2a, op2b);
+	    }
+	}
+
+      /* See if an equality test is redundant with the other comparison.  */
+      else if (code1 == EQ_EXPR)
+	{
+	  bool val;
+	  switch (code2)
+	    {
+	    case EQ_EXPR: val = (cmp == 0); break;
+	    case NE_EXPR: val = (cmp != 0); break;
+	    case LT_EXPR: val = (cmp < 0); break;
+	    case GT_EXPR: val = (cmp > 0); break;
+	    case LE_EXPR: val = (cmp <= 0); break;
+	    case GE_EXPR: val = (cmp >= 0); break;
+	    default:
+	      val = false;
+	    }
+	  if (val)
+	    return fold_build2 (code2, boolean_type_node, op2a, op2b);
+	}
+      else if (code2 == EQ_EXPR)
+	{
+	  bool val;
+	  switch (code1)
+	    {
+	    case EQ_EXPR: val = (cmp == 0); break;
+	    case NE_EXPR: val = (cmp != 0); break;
+	    case LT_EXPR: val = (cmp > 0); break;
+	    case GT_EXPR: val = (cmp < 0); break;
+	    case LE_EXPR: val = (cmp >= 0); break;
+	    case GE_EXPR: val = (cmp <= 0); break;
+	    default:
+	      val = false;
+	    }
+	  if (val)
+	    return fold_build2 (code1, boolean_type_node, op1a, op1b);
+	}
+
+      /* Chose the less restrictive of two < or <= comparisons.  */
+      else if ((code1 == LT_EXPR || code1 == LE_EXPR)
+	       && (code2 == LT_EXPR || code2 == LE_EXPR))
+	{
+	  if ((cmp < 0) || (cmp == 0 && code1 == LT_EXPR))
+	    return fold_build2 (code2, boolean_type_node, op2a, op2b);
+	  else
+	    return fold_build2 (code1, boolean_type_node, op1a, op1b);
+	}
+
+      /* Likewise chose the less restrictive of two > or >= comparisons.  */
+      else if ((code1 == GT_EXPR || code1 == GE_EXPR)
+	       && (code2 == GT_EXPR || code2 == GE_EXPR))
+	{
+	  if ((cmp > 0) || (cmp == 0 && code1 == GT_EXPR))
+	    return fold_build2 (code2, boolean_type_node, op2a, op2b);
+	  else
+	    return fold_build2 (code1, boolean_type_node, op1a, op1b);
+	}
+
+      /* Check for singleton ranges.  */
+      else if (cmp == 0
+	       && ((code1 == LT_EXPR && code2 == GT_EXPR)
+		   || (code1 == GT_EXPR && code2 == LT_EXPR)))
+	return fold_build2 (NE_EXPR, boolean_type_node, op1a, op2b);
+
+      /* Check for less/greater pairs that don't restrict the range at all.  */
+      else if (cmp >= 0
+	       && (code1 == LT_EXPR || code1 == LE_EXPR)
+	       && (code2 == GT_EXPR || code2 == GE_EXPR))
+	return boolean_true_node;
+      else if (cmp <= 0
+	       && (code1 == GT_EXPR || code1 == GE_EXPR)
+	       && (code2 == LT_EXPR || code2 == LE_EXPR))
+	return boolean_true_node;
+    }
+
+  /* Perhaps the first comparison is (NAME != 0) or (NAME == 1) where
+     NAME's definition is a truth value.  See if there are any simplifications
+     that can be done against the NAME's definition.  */
+  if (TREE_CODE (op1a) == SSA_NAME
+      && (code1 == NE_EXPR || code1 == EQ_EXPR)
+      && (integer_zerop (op1b) || integer_onep (op1b)))
+    {
+      bool invert = ((code1 == EQ_EXPR && integer_zerop (op1b))
+		     || (code1 == NE_EXPR && integer_onep (op1b)));
+      gimple stmt = SSA_NAME_DEF_STMT (op1a);
+      switch (gimple_code (stmt))
+	{
+	case GIMPLE_ASSIGN:
+	  /* Try to simplify by copy-propagating the definition.  */
+	  return or_var_with_comparison (op1a, invert, code2, op2a, op2b);
+
+	case GIMPLE_PHI:
+	  /* If every argument to the PHI produces the same result when
+	     ORed with the second comparison, we win.
+	     Do not do this unless the type is bool since we need a bool
+	     result here anyway.  */
+	  if (TREE_CODE (TREE_TYPE (op1a)) == BOOLEAN_TYPE)
+	    {
+	      tree result = NULL_TREE;
+	      unsigned i;
+	      for (i = 0; i < gimple_phi_num_args (stmt); i++)
+		{
+		  tree arg = gimple_phi_arg_def (stmt, i);
+		  
+		  /* If this PHI has itself as an argument, ignore it.
+		     If all the other args produce the same result,
+		     we're still OK.  */
+		  if (arg == gimple_phi_result (stmt))
+		    continue;
+		  else if (TREE_CODE (arg) == INTEGER_CST)
+		    {
+		      if (invert ? integer_zerop (arg) : integer_nonzerop (arg))
+			{
+			  if (!result)
+			    result = boolean_true_node;
+			  else if (!integer_onep (result))
+			    return NULL_TREE;
+			}
+		      else if (!result)
+			result = fold_build2 (code2, boolean_type_node,
+					      op2a, op2b);
+		      else if (!same_bool_comparison_p (result,
+							code2, op2a, op2b))
+			return NULL_TREE;
+		    }
+		  else if (TREE_CODE (arg) == SSA_NAME)
+		    {
+		      tree temp = or_var_with_comparison (arg, invert,
+							  code2, op2a, op2b);
+		      if (!temp)
+			return NULL_TREE;
+		      else if (!result)
+			result = temp;
+		      else if (!same_bool_result_p (result, temp))
+			return NULL_TREE;
+		    }
+		  else
+		    return NULL_TREE;
+		}
+	      return result;
+	    }
+
+	default:
+	  break;
+	}
+    }
+  return NULL_TREE;
+}
+
+/* Try to simplify the OR of two comparisons, specified by
+   (OP1A CODE1 OP1B) and (OP2B CODE2 OP2B), respectively.
+   If this can be simplified to a single expression (without requiring
+   introducing more SSA variables to hold intermediate values),
+   return the resulting tree.  Otherwise return NULL_TREE.
+   If the result expression is non-null, it has boolean type.  */
+
+tree
+maybe_fold_or_comparisons (enum tree_code code1, tree op1a, tree op1b,
+			   enum tree_code code2, tree op2a, tree op2b)
+{
+  tree t = or_comparisons_1 (code1, op1a, op1b, code2, op2a, op2b);
+  if (t)
+    return t;
+  else
+    return or_comparisons_1 (code2, op2a, op2b, code1, op1a, op1b);
+}