beifg: Simplify the implementation of be_ifg_foreach_node().
[libfirm] / ir / opt / opt_confirms.c
index ee23ee5..3049e0e 100644 (file)
@@ -1,33 +1,30 @@
 /*
- * Project:     libFIRM
- * File name:   ir/opt/opt_confirms.c
- * Purpose:     Optimizations regarding Confirm nodes
- * Author:      Michael Beck
- * Modified by:
- * Created:
- * CVS-ID:      $Id$
- * Copyright:   (c) 1998-2005 Universität Karlsruhe
- * Licence:     This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
+ * This file is part of libFirm.
+ * Copyright (C) 2012 University of Karlsruhe.
  */
 
-#ifdef HAVE_CONFIG_H
-# include "config.h"
-#endif
+/**
+ * @file
+ * @brief   Optimizations regarding Confirm nodes.
+ * @author  Michael Beck
+ */
+#include "config.h"
 
 #undef DEBUG_CONFIRM
 
 #include "tv_t.h"
+#include "irnode_t.h"
 #include "iropt_t.h"
 #include "iropt_dbg.h"
-#include "opt_confirms.h"
+#include "iroptimize.h"
 #include "irflag_t.h"
 #include "irprintf.h"
 
 enum range_tags {
-  MIN_INCLUDED = 0x00,  /**< [min, ... */
-  MAX_INCLUDED = 0x00,  /**< ..., max] */
-  MIN_EXCLUDED = 0x01,  /**< (min, ... */
-  MAX_EXCLUDED = 0x02   /**< ..., max) */
+       MIN_INCLUDED = 0x00,  /**< [min, ... */
+       MAX_INCLUDED = 0x00,  /**< ..., max] */
+       MIN_EXCLUDED = 0x01,  /**< (min, ... */
+       MAX_EXCLUDED = 0x02   /**< ..., max) */
 };
 
 /**
@@ -38,42 +35,42 @@ enum range_tags {
  * such kind of operation, we use border flags allowing
  * all intervals.
  */
-typedef struct _interval_t {
-  tarval        *min;   /**< lowest border */
-  tarval        *max;   /**< highest border */
-  unsigned char flags;  /**< border flags */
+typedef struct interval_t {
+       ir_tarval     *min;   /**< lowest border */
+       ir_tarval     *max;   /**< highest border */
+       unsigned char flags;  /**< border flags */
 } interval_t;
 
 #ifdef DEBUG_CONFIRM
 
-#define compare_iv(l_iv, r_iv, pnc)            compare_iv_dbg(l_iv, r_iv, pnc)
+#define compare_iv(l_iv, r_iv, relation)    compare_iv_dbg(l_iv, r_iv, relation)
 
 /* forward */
-static tarval *compare_iv_dbg(const interval_t *l_iv, const interval_t *r_iv, pn_Cmp pnc);
+static tarval *compare_iv_dbg(const interval_t *l_iv, const interval_t *r_iv, ir_relation relation);
 
 /* triangle */
-#define DBG_OUT_TR(l_pnc, l_bound, r_pnc, r_bound, pnc, v) \
+#define DBG_OUT_TR(l_relation, l_bound, r_relation, r_bound, relation, v) \
   ir_printf("In %e:\na %= %n && b %= %n  ==>  a %= b == %s\n", \
     get_irg_entity(current_ir_graph), \
-    l_pnc, l_bound, r_pnc, r_bound, pnc, v);
+    l_relation, l_bound, r_relation, r_bound, relation, v)
 
 /* right side */
-#define DBG_OUT_R(r_pnc, r_bound, left, pnc, right, v) \
+#define DBG_OUT_R(r_relation, r_bound, left, relation, right, v) \
   ir_printf("In %e:\na %= %n ==>  %n %= %n == %s\n", \
     get_irg_entity(current_ir_graph), \
-    r_pnc, r_bound, left, pnc, right, v);
+    r_relation, r_bound, left, relation, right, v)
 
 /* left side */
-#define DBG_OUT_L(l_pnc, l_bound, left, pnc, right, v) \
+#define DBG_OUT_L(l_relation, l_bound, left, relation, right, v) \
   ir_printf("In %e:\na %= %n ==>  %n %= %n == %s\n", \
     get_irg_entity(current_ir_graph), \
-    l_pnc, l_bound, left, pnc, right, v);
+    l_relation, l_bound, left, relation, right, v)
 
 #else
 
-#define DBG_OUT_TR(l_pnc, l_bound, r_pnc, r_bound, pnc, v)
-#define DBG_OUT_R(r_pnc, r_bound, left, pnc, right, v)
-#define DBG_OUT_L(l_pnc, l_bound, left, pnc, right, v)
+#define DBG_OUT_TR(l_relation, l_bound, r_relation, r_bound, relation, v)  (void)0
+#define DBG_OUT_R(r_relation, r_bound, left, relation, right, v)  (void)0
+#define DBG_OUT_L(l_relation, l_bound, left, relation, right, v)  (void)0
 
 #endif /* DEBUG_CONFIRM */
 
@@ -83,63 +80,77 @@ static tarval *compare_iv_dbg(const interval_t *l_iv, const interval_t *r_iv, pn
  * This is a often needed case, so we handle here Confirm
  * nodes too.
  */
-int value_not_zero(ir_node *n)
+int value_not_zero(const ir_node *n, const ir_node **confirm)
 {
-#define RET_ON(x)  if (x) return 1; break
-
-  tarval *tv;
-  ir_mode *mode = get_irn_mode(n);
-  pn_Cmp pnc;
-
-  while (get_irn_op(n) == op_Confirm) {
-    /*
-     * Note: A Confirm is never after a Const. So,
-     * we simply can check the bound for being a Const
-     * without the fear that is might be hidden by a further Confirm.
-     */
-    tv = value_of(get_Confirm_bound(n));
-    if (tv == tarval_bad)
-      return 0;
-
-    pnc  = tarval_cmp(tv, get_mode_null(mode));
-
-    /*
-     * Beware: C might by a NaN. It is not clear, what we should do
-     * than. Of course a NaN is != 0, but we might use this function
-     * to remove up Exceptions, and NaN's might generate Exception.
-     * So, we do NOT handle NaNs here for safety.
-     *
-     * Note that only the C != 0 case need additional checking.
-     */
-    switch (get_Confirm_cmp(n)) {
-    case pn_Cmp_Eq: /* n == C /\ C != 0 ==> n != 0 */
-      RET_ON(pnc != pn_Cmp_Eq && pnc != pn_Cmp_Uo);
-    case pn_Cmp_Lg: /* n != C /\ C == 0 ==> n != 0 */
-      RET_ON(pnc == pn_Cmp_Eq);
-    case pn_Cmp_Lt: /* n <  C /\ C <= 0 ==> n != 0 */
-      RET_ON(pnc == pn_Cmp_Lt || pnc == pn_Cmp_Eq);
-    case pn_Cmp_Le: /* n <= C /\ C <  0 ==> n != 0 */
-      RET_ON(pnc == pn_Cmp_Lt);
-    case pn_Cmp_Ge: /* n >= C /\ C >  0 ==> n != 0 */
-      RET_ON(pnc == pn_Cmp_Gt);
-    case pn_Cmp_Gt: /* n >  C /\ C >= 0 ==> n != 0 */
-      RET_ON(pnc == pn_Cmp_Gt || pnc == pn_Cmp_Eq);
-    default:
-      break;
-    }
-
-    /* there might be several Confirms one after other that form an interval */
-    n = get_Confirm_value(n);
-  }
-  tv = value_of(n);
-
-  if (tv == tarval_bad)
-    return 0;
-
-  pnc = tarval_cmp(tv, get_mode_null(mode));
-
-  /* again, need check for NaN */
-  return (pnc != pn_Cmp_Eq) && (pnc != pn_Cmp_Uo);
+#define RET_ON(x)  if (x) { *confirm = n; return 1; } break
+
+       ir_tarval *tv;
+       ir_mode *mode = get_irn_mode(n);
+       ir_relation relation;
+
+       *confirm = NULL;
+
+       /* there might be several Confirms one after other that form an interval */
+       for (;;) {
+               if (is_Minus(n)) {
+                       /* we can safely skip Minus when checking for != 0 */
+                       n = get_unop_op(n);
+                       continue;
+               }
+               if (! is_Confirm(n))
+                       break;
+
+               /*
+                * Note: A Confirm is never after a Const. So,
+                * we simply can check the bound for being a Const
+                * without the fear that is might be hidden by a further Confirm.
+                */
+               tv = value_of(get_Confirm_bound(n));
+               if (tv == tarval_bad) {
+                       n = get_Confirm_value(n);
+                       continue;
+               }
+
+               relation = tarval_cmp(tv, get_mode_null(mode));
+
+               /*
+                * Beware: C might by a NaN. It is not clear, what we should do
+                * than. Of course a NaN is != 0, but we might use this function
+                * to remove up Exceptions, and NaN's might generate Exception.
+                * So, we do NOT handle NaNs here for safety.
+                *
+                * Note that only the C != 0 case need additional checking.
+                */
+               switch (get_Confirm_relation(n)) {
+               case ir_relation_equal: /* n == C /\ C != 0 ==> n != 0 */
+                       RET_ON(relation != ir_relation_equal && relation != ir_relation_unordered);
+               case ir_relation_less_greater: /* n != C /\ C == 0 ==> n != 0 */
+                       RET_ON(relation == ir_relation_equal);
+               case ir_relation_less: /* n <  C /\ C <= 0 ==> n != 0 */
+                       RET_ON(relation == ir_relation_less || relation == ir_relation_equal);
+               case ir_relation_less_equal: /* n <= C /\ C <  0 ==> n != 0 */
+                       RET_ON(relation == ir_relation_less);
+               case ir_relation_greater_equal: /* n >= C /\ C >  0 ==> n != 0 */
+                       RET_ON(relation == ir_relation_greater);
+               case ir_relation_greater: /* n >  C /\ C >= 0 ==> n != 0 */
+                       RET_ON(relation == ir_relation_greater || relation == ir_relation_equal);
+               default:
+                       break;
+               }
+               n = get_Confirm_value(n);
+       }
+       /* global entities are never NULL */
+       if (is_SymConst_addr_ent(n))
+               return true;
+
+       tv = value_of(n);
+       if (tv == tarval_bad)
+               return false;
+
+       relation = tarval_cmp(tv, get_mode_null(mode));
+
+       /* again, need check for NaN */
+       return (relation != ir_relation_equal) && (relation != ir_relation_unordered);
 
 #undef RET_ON
 }
@@ -147,126 +158,169 @@ int value_not_zero(ir_node *n)
 /*
  * Check, if the value of a node cannot represent a NULL pointer.
  *
- * - Casts are skipped
- * - If sel_based_null_check_elim is enabled, all
- *   Sel nodes can be skipped.
+ * - Sels are skipped
  * - A SymConst(entity) is NEVER a NULL pointer
  * - Confirms are evaluated
  */
-int value_not_null(ir_node *n)
+int value_not_null(const ir_node *n, const ir_node **confirm)
 {
-  ir_op *op;
-
-  n  = skip_Cast(n);
-  op = get_irn_op(n);
-  assert(mode_is_reference(get_irn_mode(n)));
-  if (get_opt_sel_based_null_check_elim()) {
-    /* skip all Sel nodes and Cast's */
-    while (op == op_Sel) {
-      n = skip_Cast(get_Sel_ptr(n));
-      op = get_irn_op(n);
-    }
-  }
-  if (op == op_SymConst && get_SymConst_kind(n) == symconst_addr_ent)
-    return 1;
-  if (op == op_Confirm) {
-    if (get_Confirm_cmp(n) == pn_Cmp_Lg &&
-        classify_Const(get_Confirm_bound(n)) == CNST_NULL)
-      return 1;
-  }
-  return 0;
+       ir_tarval *tv;
+
+       *confirm = NULL;
+
+       tv = value_of(n);
+       if (tarval_is_constant(tv) && ! tarval_is_null(tv))
+               return 1;
+
+       assert(mode_is_reference(get_irn_mode(n)));
+       /* skip all Sel nodes */
+       while (is_Sel(n)) {
+               n = get_Sel_ptr(n);
+       }
+       while (1) {
+               if (is_Proj(n)) { n = get_Proj_pred(n); continue; }
+               break;
+       }
+
+       if (is_SymConst_addr_ent(n)) {
+               /* global references are never NULL */
+               return 1;
+       } else if (n == get_irg_frame(get_irn_irg(n))) {
+               /* local references are never NULL */
+               return 1;
+       } else if (is_Alloc(n)) {
+               /* alloc never returns NULL (it throws an exception instead) */
+               return 1;
+       } else {
+               /* check for more Confirms */
+               for (; is_Confirm(n); n = get_Confirm_value(n)) {
+                       if (get_Confirm_relation(n) == ir_relation_less_greater) {
+                               ir_node   *bound = get_Confirm_bound(n);
+                               ir_tarval *tv    = value_of(bound);
+
+                               if (tarval_is_null(tv)) {
+                                       *confirm = n;
+                                       return 1;
+                               }
+                       }
+               }
+       }
+       return 0;
 }
 
+#ifdef __cplusplus
+extern "C++" {
+       static inline ir_value_classify_sign operator *(ir_value_classify_sign sign, int mul) {
+       return (ir_value_classify_sign) (sign*mul);
+       }
+}
+#endif
+
 /*
  * Check, if the value of a node can be confirmed >= 0 or <= 0,
  * If the mode of the value did not honor signed zeros, else
  * check for >= 0 or < 0.
  */
-value_classify classify_value_sign(ir_node *n)
+ir_value_classify_sign classify_value_sign(ir_node *n)
 {
-  tarval *tv, *c;
-  ir_mode *mode;
-  pn_Cmp cmp, ncmp;
-
-  if (get_irn_op(n) != op_Confirm)
-    return VALUE_UNKNOWN;
-
-  tv  = value_of(get_Confirm_bound(n));
-  if (tv == tarval_bad)
-    return VALUE_UNKNOWN;
-
-  mode = get_irn_mode(n);
-
-  /*
-   * We can handle only >=, >, <, <= cases.
-   * We could handle == too, but this will be optimized into
-   * a constant either.
-   *
-   * Note that for integer modes we have a slightly better
-   * optimization possibilities, so we handle this
-   * different.
-   */
-  cmp = get_Confirm_cmp(n);
-
-  switch (cmp) {
-  case pn_Cmp_Lt:
-    /*
-     * must be x < c <= 1 to be useful if integer mode and -0 = 0
-     *         x < c <= 0 to be useful else
-     */
-  case pn_Cmp_Le:
-    /*
-     * must be x <= c < 1 to be useful if integer mode and -0 = 0
-     *         x <= c < 0 to be useful else
-     */
-    c = mode_is_int(mode) && mode_honor_signed_zeros(mode) ?
-      get_mode_one(mode) : get_mode_null(mode);
-
-    ncmp = tarval_cmp(tv, c);
-    if (ncmp == pn_Cmp_Eq)
-      ncmp = pn_Cmp_Le;
-
-    if (cmp != (ncmp ^ pn_Cmp_Eq))
-      return VALUE_UNKNOWN;
-
-    /* yep, negative */
-    return VALUE_NEGATIVE;
-
-  case pn_Cmp_Ge:
-    /*
-     * must be x >= c > -1 to be useful if integer mode
-     *         x >= c >= 0 to be useful else
-     */
-  case pn_Cmp_Gt:
-    /*
-     * must be x > c >= -1 to be useful if integer mode
-     *         x > c >= 0 to be useful else
-     */
-    if (mode_is_int(mode)) {
-      c = get_mode_minus_one(mode);
-
-      ncmp = tarval_cmp(tv, c);
-      if (ncmp == pn_Cmp_Eq)
-        ncmp = pn_Cmp_Ge;
-
-      if (cmp != (ncmp ^ pn_Cmp_Eq))
-        return VALUE_UNKNOWN;
-    }
-    else {
-      c = get_mode_minus_one(mode);
-
-      ncmp = tarval_cmp(tv, c);
-
-      if (ncmp != pn_Cmp_Eq && ncmp != pn_Cmp_Gt)
-        return VALUE_UNKNOWN;
-    }
-
-    /* yep, positive */
-    return VALUE_POSITIVE;
-
-  default:
-    return VALUE_UNKNOWN;
-  }
+       ir_tarval *tv, *c;
+       ir_mode *mode;
+       ir_relation cmp, ncmp;
+       int negate = 1;
+
+       for (;;) {
+               unsigned code = get_irn_opcode(n);
+
+               switch (code) {
+               case iro_Minus:
+                       negate *= -1;
+                       n = get_Minus_op(n);
+                       continue;
+               case iro_Confirm:
+                       break;
+               default:
+                       return value_classified_unknown;
+               }
+               break;
+       }
+       if (!is_Confirm(n))
+               return value_classified_unknown;
+
+       tv  = value_of(get_Confirm_bound(n));
+       if (tv == tarval_bad)
+               return value_classified_unknown;
+
+       mode = get_irn_mode(n);
+
+       /*
+        * We can handle only >=, >, <, <= cases.
+        * We could handle == too, but this will be optimized into
+        * a constant either.
+        *
+        * Note that for integer modes we have a slightly better
+        * optimization possibilities, so we handle this
+        * different.
+        */
+       cmp = get_Confirm_relation(n);
+
+       switch (cmp) {
+       case ir_relation_less:
+               /*
+                * must be x < c <= 1 to be useful if integer mode and -0 = 0
+                *         x < c <= 0 to be useful else
+                */
+       case ir_relation_less_equal:
+               /*
+                * must be x <= c < 1 to be useful if integer mode and -0 = 0
+                *         x <= c < 0 to be useful else
+                */
+               c = mode_is_int(mode) && mode_honor_signed_zeros(mode) ?
+                       get_mode_one(mode) : get_mode_null(mode);
+
+               ncmp = tarval_cmp(tv, c);
+               if (ncmp == ir_relation_equal)
+                       ncmp = ir_relation_less_equal;
+
+               if (cmp != (ncmp ^ ir_relation_equal))
+                       return value_classified_unknown;
+
+               /* yep, negative */
+               return value_classified_negative * negate;
+
+       case ir_relation_greater_equal:
+               /*
+                * must be x >= c > -1 to be useful if integer mode
+                *         x >= c >= 0 to be useful else
+                */
+       case ir_relation_greater:
+               /*
+                * must be x > c >= -1 to be useful if integer mode
+                *         x > c >= 0 to be useful else
+                */
+               if (mode_is_int(mode)) {
+                       c = get_mode_minus_one(mode);
+
+                       ncmp = tarval_cmp(tv, c);
+                       if (ncmp == ir_relation_equal)
+                               ncmp = ir_relation_greater_equal;
+
+                       if (cmp != (ncmp ^ ir_relation_equal))
+                               return value_classified_unknown;
+               } else {
+                       c = get_mode_minus_one(mode);
+
+                       ncmp = tarval_cmp(tv, c);
+
+                       if (ncmp != ir_relation_equal && ncmp != ir_relation_greater)
+                               return value_classified_unknown;
+               }
+
+               /* yep, positive */
+               return value_classified_positive * negate;
+
+       default:
+               return value_classified_unknown;
+       }
 }
 
 /**
@@ -275,458 +329,468 @@ value_classify classify_value_sign(ir_node *n)
  * @return the filled interval or NULL if no interval
  *         can be created (happens only on floating point
  */
-static interval_t *get_interval_from_tv(interval_t *iv, tarval *tv)
+static interval_t *get_interval_from_tv(interval_t *iv, ir_tarval *tv)
 {
-  ir_mode *mode = get_tarval_mode(tv);
-
-  if (tv == tarval_bad) {
-    if (mode_is_float(mode)) {
-      /* NaN could be included which we cannot handle */
-      iv->min   = tarval_bad;
-      iv->max   = tarval_bad;
-      iv->flags = MIN_EXCLUDED | MAX_EXCLUDED;
-      return NULL;
-    }
-    else {
-      /* [-oo, +oo] */
-      iv->min   = get_mode_min(mode);
-      iv->max   = get_mode_max(mode);
-      iv->flags = MIN_INCLUDED | MAX_INCLUDED;
-      return iv;
-    }
-  }
-
-  if (mode_is_float(mode)) {
-    if (tv == get_mode_NAN(mode)) {
-      /* arg, we cannot handle NaN's. */
-      iv->min   = tarval_bad;
-      iv->max   = tarval_bad;
-      iv->flags = MIN_EXCLUDED | MAX_EXCLUDED;
-      return NULL;
-    }
-  }
-
-  /* [tv, tv] */
-  iv->min   = tv;
-  iv->max   = tv;
-  iv->flags = MIN_INCLUDED | MAX_INCLUDED;
-
-  return iv;
+       ir_mode *mode = get_tarval_mode(tv);
+
+       if (tv == tarval_bad) {
+               if (mode_is_float(mode)) {
+                       /* NaN could be included which we cannot handle */
+                       iv->min   = tarval_bad;
+                       iv->max   = tarval_bad;
+                       iv->flags = MIN_EXCLUDED | MAX_EXCLUDED;
+                       return NULL;
+               } else {
+                       /* [-oo, +oo] */
+                       iv->min   = get_mode_min(mode);
+                       iv->max   = get_mode_max(mode);
+                       iv->flags = MIN_INCLUDED | MAX_INCLUDED;
+                       return iv;
+               }
+       }
+
+       if (mode_is_float(mode)) {
+               if (tv == get_mode_NAN(mode)) {
+                       /* arg, we cannot handle NaN's. */
+                       iv->min   = tarval_bad;
+                       iv->max   = tarval_bad;
+                       iv->flags = MIN_EXCLUDED | MAX_EXCLUDED;
+                       return NULL;
+               }
+       }
+
+       /* [tv, tv] */
+       iv->min   = tv;
+       iv->max   = tv;
+       iv->flags = MIN_INCLUDED | MAX_INCLUDED;
+
+       return iv;
 }
 
 /**
  * construct an interval from a Confirm
  *
- * @param iv     an empty interval, will be filled
- * @param bound  the bound value
- * @param pnc    the Confirm compare relation
+ * @param iv       an empty interval, will be filled
+ * @param bound    the bound value
+ * @param relation the Confirm compare relation
  *
  * @return the filled interval or NULL if no interval
  *         can be created (happens only on floating point
  */
-static interval_t *get_interval(interval_t *iv, ir_node *bound, pn_Cmp pnc)
+static interval_t *get_interval(interval_t *iv, ir_node *bound, ir_relation relation)
 {
-  ir_mode *mode = get_irn_mode(bound);
-  tarval  *tv   = value_of(bound);
-
-  if (tv == tarval_bad) {
-    /* There is nothing we could do here. For integer
-     * modes we could return [-oo, +oo], but there is
-     * nothing we could deduct from such an interval.
-     * So, speed things up and return unknown.
-     */
-    iv->min   = tarval_bad;
-    iv->max   = tarval_bad;
-    iv->flags = MIN_EXCLUDED | MAX_EXCLUDED;
-    return NULL;
-  }
-
-  if (mode_is_float(mode)) {
-    if (tv == get_mode_NAN(mode)) {
-      /* arg, we cannot handle NaN's. */
-      iv->min   = tarval_bad;
-      iv->max   = tarval_bad;
-      iv->flags = MIN_EXCLUDED | MAX_EXCLUDED;
-
-      return NULL;
-    }
-  }
-
-  /* check which side is known */
-  switch (pnc) {
-  case pn_Cmp_Eq:
-    /* [tv, tv] */
-    iv->min   =
-    iv->max   = tv;
-    iv->flags = MIN_INCLUDED | MAX_INCLUDED;
-    break;
-
-  case pn_Cmp_Le:
-    /* [-oo, tv] */
-    iv->min   = get_mode_min(mode);
-    iv->max   = tv;
-    iv->flags = MIN_INCLUDED | MAX_INCLUDED;
-    break;
-
-  case pn_Cmp_Lt:
-    /* [-oo, tv) */
-    iv->min   = get_mode_min(mode);
-    iv->max   = tv;
-    iv->flags = MIN_INCLUDED | MAX_EXCLUDED;
-    break;
-
-  case pn_Cmp_Gt:
-    /* (tv, +oo] */
-    iv->min   = tv;
-    iv->max   = get_mode_max(mode);
-    iv->flags = MIN_EXCLUDED | MAX_INCLUDED;
-    break;
-
-  case pn_Cmp_Ge:
-    /* [tv, +oo] */
-    iv->min   = tv;
-    iv->max   = get_mode_max(mode);
-    iv->flags = MIN_INCLUDED | MAX_INCLUDED;
-    break;
-
-  case pn_Cmp_Leg:
-    /*
-     * Ordered means, that at least neither
-     * our bound nor our value ara NaN's
-     */
-    /* [-oo, +oo] */
-    iv->min   = get_mode_min(mode);
-    iv->max   = get_mode_max(mode);
-    iv->flags = MIN_INCLUDED | MAX_INCLUDED;
-    break;
-
-  default:
-    /*
-     * We do not handle UNORDERED, as a NaN
-     * could be included in the interval.
-     */
-    iv->min   = tarval_bad;
-    iv->max   = tarval_bad;
-    iv->flags = MIN_EXCLUDED | MAX_EXCLUDED;
-    return NULL;
-  }
-
-  if (iv->min != tarval_bad && iv->max != tarval_bad)
-    return iv;
-  return NULL;
+       ir_mode   *mode = get_irn_mode(bound);
+       ir_tarval *tv   = value_of(bound);
+
+       if (tv == tarval_bad) {
+               /* There is nothing we could do here. For integer
+                * modes we could return [-oo, +oo], but there is
+                * nothing we could deduct from such an interval.
+                * So, speed things up and return unknown.
+                */
+               iv->min   = tarval_bad;
+               iv->max   = tarval_bad;
+               iv->flags = MIN_EXCLUDED | MAX_EXCLUDED;
+               return NULL;
+       }
+
+       if (mode_is_float(mode)) {
+               if (tv == get_mode_NAN(mode)) {
+                       /* arg, we cannot handle NaN's. */
+                       iv->min   = tarval_bad;
+                       iv->max   = tarval_bad;
+                       iv->flags = MIN_EXCLUDED | MAX_EXCLUDED;
+
+                       return NULL;
+               }
+       }
+
+       /* check which side is known */
+       switch (relation) {
+       case ir_relation_equal:
+               /* [tv, tv] */
+               iv->min   =
+                       iv->max   = tv;
+               iv->flags = MIN_INCLUDED | MAX_INCLUDED;
+               break;
+
+       case ir_relation_less_equal:
+               /* [-oo, tv] */
+               iv->min   = get_mode_min(mode);
+               iv->max   = tv;
+               iv->flags = MIN_INCLUDED | MAX_INCLUDED;
+               break;
+
+       case ir_relation_less:
+               /* [-oo, tv) */
+               iv->min   = get_mode_min(mode);
+               iv->max   = tv;
+               iv->flags = MIN_INCLUDED | MAX_EXCLUDED;
+               break;
+
+       case ir_relation_greater:
+               /* (tv, +oo] */
+               iv->min   = tv;
+               iv->max   = get_mode_max(mode);
+               iv->flags = MIN_EXCLUDED | MAX_INCLUDED;
+               break;
+
+       case ir_relation_greater_equal:
+               /* [tv, +oo] */
+               iv->min   = tv;
+               iv->max   = get_mode_max(mode);
+               iv->flags = MIN_INCLUDED | MAX_INCLUDED;
+               break;
+
+       case ir_relation_less_equal_greater:
+               /*
+                * Ordered means, that at least neither
+                * our bound nor our value ara NaN's
+                */
+               /* [-oo, +oo] */
+               iv->min   = get_mode_min(mode);
+               iv->max   = get_mode_max(mode);
+               iv->flags = MIN_INCLUDED | MAX_INCLUDED;
+               break;
+
+       default:
+               /*
+                * We do not handle UNORDERED, as a NaN
+                * could be included in the interval.
+                */
+               iv->min   = tarval_bad;
+               iv->max   = tarval_bad;
+               iv->flags = MIN_EXCLUDED | MAX_EXCLUDED;
+               return NULL;
+       }
+
+       if (iv->min != tarval_bad && iv->max != tarval_bad)
+               return iv;
+       return NULL;
 }
 
 /**
- * Try to evaluate l_iv pnc r_iv.
+ * Try to evaluate l_iv relation r_iv.
  *
- * @param l_iv   the left interval
- * @param r_iv   the right interval
- * @param pnc    the compare relation
+ * @param l_iv      the left interval
+ * @param r_iv      the right interval
+ * @param relation  the compare relation
  *
  * @return
  *   tarval_b_true or tarval_b_false it it can be evaluated,
  *   tarval_bad else
  */
-static tarval *(compare_iv)(const interval_t *l_iv, const interval_t *r_iv, pn_Cmp pnc)
+static ir_tarval *(compare_iv)(const interval_t *l_iv, const interval_t *r_iv, ir_relation relation)
 {
-  pn_Cmp res;
-  unsigned flags;
-  tarval *tv_true = tarval_b_true, *tv_false = tarval_b_false;
-
-  /* if one interval contains NaNs, we cannot evaluate anything */
-  if (! l_iv || ! r_iv)
-    return tarval_bad;
-
-  /* we can only check ordered relations */
-  if (pnc & pn_Cmp_Uo) {
-    tarval *t;
-
-    pnc      = get_negated_pnc(pnc, get_tarval_mode(l_iv->min));
-    t        = tv_true;
-    tv_true  = tv_false;
-    tv_false = t;
-  }
-
-  /* if we have > or >=, we do the inverse to save some cases */
-  if (pnc == pn_Cmp_Ge || pnc == pn_Cmp_Gt) {
-    const interval_t *t;
-
-    pnc  = get_inversed_pnc(pnc);
-    t    = l_iv;
-    l_iv = r_iv;
-    r_iv = t;
-  }
-
-  /* now, only the following cases remains */
-  switch (pnc) {
-  case pn_Cmp_Eq:
-    /* two intervals can be compared for equality only if they are a single value */
-    if (l_iv->min == l_iv->max && r_iv->min == r_iv->max)
-      return tarval_cmp(l_iv->min, r_iv->min) == pn_Cmp_Eq ? tv_true : tv_false;
-
-    /* if both intervals do not intersect, it is never equal */
-    res = tarval_cmp(l_iv->max, r_iv->min);
-
-    /* b < c ==> [a,b] != [c,d] */
-    if (res == pn_Cmp_Lt)
-      return tv_false;
-
-    /* b <= c ==> [a,b) != [c,d]  AND [a,b] != (c,d] */
-    if ((l_iv->flags & MAX_EXCLUDED || r_iv->flags & MIN_EXCLUDED)
-        && (res == pn_Cmp_Eq))
-      return tv_false;
-
-    res = tarval_cmp(r_iv->max, l_iv->min);
-
-    /* d < a ==> [c,d] != [a,b] */
-    if (res == pn_Cmp_Lt)
-      return tv_false;
-
-    /* d <= a ==> [c,d) != [a,b]  AND [c,d] != (a,b] */
-    if ((r_iv->flags & MAX_EXCLUDED || l_iv->flags & MIN_EXCLUDED)
-        && (res == pn_Cmp_Eq))
-      return tv_false;
-    break;
-
-  case pn_Cmp_Lg:
-    /* two intervals can be compared for not equality only if they are a single value */
-    if (l_iv->min == l_iv->max && r_iv->min == r_iv->max)
-      return tarval_cmp(l_iv->min, r_iv->min) != pn_Cmp_Eq ? tv_true : tv_false;
-    break;
-
-  case pn_Cmp_Lt:
-    res = tarval_cmp(l_iv->max, r_iv->min);
-
-    /* [a, b] < [c, d]  <==> b < c */
-    if (res == pn_Cmp_Lt)
-      return tv_true;
-
-    /* if one border is excluded, b <= c is enough */
-    if ((l_iv->flags & MAX_EXCLUDED || r_iv->flags & MIN_EXCLUDED) &&
-        res == pn_Cmp_Eq)
-      return tv_true;
-
-    /* [a, b] >= [c, d] <==> a > d */
-    res = tarval_cmp(l_iv->min, r_iv->max);
-    if (res == pn_Cmp_Gt)
-      return tv_false;
-
-    /* if one border is excluded, a >= d is enough */
-    if ((l_iv->flags & MIN_EXCLUDED || r_iv->flags & MAX_EXCLUDED) &&
-      res == pn_Cmp_Eq)
-      return tv_false;
-    break;
-
-  case pn_Cmp_Le:
-    /* [a, b) <= [c, d] or [a, b] <= (c, d]  <==> b <= c */
-    flags = (l_iv->flags & MAX_EXCLUDED) | (r_iv->flags & MIN_EXCLUDED);
-    if (flags) {
-      res = tarval_cmp(l_iv->max, r_iv->min);
-
-      if (res == pn_Cmp_Lt || res == pn_Cmp_Eq)
-        return tv_true;
-    }
-
-    res = tarval_cmp(l_iv->min, r_iv->max);
-
-    /* [a, b] > [c, d] <==> a > d */
-    if (res == pn_Cmp_Gt)
-      return tv_false;
-
-    /* if one border is excluded, a >= d is enough */
-    if ((l_iv->flags & MIN_EXCLUDED || r_iv->flags & MAX_EXCLUDED) &&
-        res == pn_Cmp_Eq)
-      return tv_false;
-    break;
-
-  case pn_Cmp_Leg:
-    /* Hmm. if both are intervals, we can find an order */
-    return tv_true;
-
-  default:
-    return tarval_bad;
-  }
-  return tarval_bad;
+       ir_relation res;
+       unsigned    flags;
+       ir_tarval  *tv_true = tarval_b_true, *tv_false = tarval_b_false;
+
+       /* if one interval contains NaNs, we cannot evaluate anything */
+       if (! l_iv || ! r_iv)
+               return tarval_bad;
+
+       /* we can only check ordered relations */
+       if (relation & ir_relation_unordered) {
+               ir_tarval *t;
+
+               relation = get_negated_relation(relation);
+               t        = tv_true;
+               tv_true  = tv_false;
+               tv_false = t;
+       }
+
+       /* if we have > or >=, we do the inverse to save some cases */
+       if (relation == ir_relation_greater_equal || relation == ir_relation_greater) {
+               const interval_t *t;
+
+               relation = get_inversed_relation(relation);
+               t        = l_iv;
+               l_iv     = r_iv;
+               r_iv     = t;
+       }
+
+       /* now, only the following cases remains */
+       switch (relation) {
+       case ir_relation_equal:
+               /* two intervals can be compared for equality only if they are a single value */
+               if (l_iv->min == l_iv->max && r_iv->min == r_iv->max)
+                       return tarval_cmp(l_iv->min, r_iv->min) == ir_relation_equal ? tv_true : tv_false;
+
+               /* if both intervals do not intersect, it is never equal */
+               res = tarval_cmp(l_iv->max, r_iv->min);
+
+               /* b < c ==> [a,b] != [c,d] */
+               if (res == ir_relation_less)
+                       return tv_false;
+
+               /* b <= c ==> [a,b) != [c,d]  AND [a,b] != (c,d] */
+               if ((l_iv->flags & MAX_EXCLUDED || r_iv->flags & MIN_EXCLUDED)
+                       && (res == ir_relation_equal))
+                       return tv_false;
+
+               res = tarval_cmp(r_iv->max, l_iv->min);
+
+               /* d < a ==> [c,d] != [a,b] */
+               if (res == ir_relation_less)
+                       return tv_false;
+
+               /* d <= a ==> [c,d) != [a,b]  AND [c,d] != (a,b] */
+               if ((r_iv->flags & MAX_EXCLUDED || l_iv->flags & MIN_EXCLUDED)
+                       && (res == ir_relation_equal))
+                       return tv_false;
+               break;
+
+       case ir_relation_less_greater:
+               /* two intervals can be compared for not equality only if they are a single value */
+               if (l_iv->min == l_iv->max && r_iv->min == r_iv->max)
+                       return tarval_cmp(l_iv->min, r_iv->min) != ir_relation_equal ? tv_true : tv_false;
+               break;
+
+       case ir_relation_less:
+               res = tarval_cmp(l_iv->max, r_iv->min);
+
+               /* [a, b] < [c, d]  <==> b < c */
+               if (res == ir_relation_less)
+                       return tv_true;
+
+               /* if one border is excluded, b <= c is enough */
+               if ((l_iv->flags & MAX_EXCLUDED || r_iv->flags & MIN_EXCLUDED) &&
+                       res == ir_relation_equal)
+                       return tv_true;
+
+               /* [a, b] >= [c, d] <==> a > d */
+               res = tarval_cmp(l_iv->min, r_iv->max);
+               if (res == ir_relation_greater)
+                       return tv_false;
+
+               /* if one border is excluded, a >= d is enough */
+               if ((l_iv->flags & MIN_EXCLUDED || r_iv->flags & MAX_EXCLUDED) &&
+                       res == ir_relation_equal)
+                       return tv_false;
+               break;
+
+       case ir_relation_less_equal:
+               /* [a, b) <= [c, d] or [a, b] <= (c, d]  <==> b <= c */
+               flags = (l_iv->flags & MAX_EXCLUDED) | (r_iv->flags & MIN_EXCLUDED);
+               if (flags) {
+                       res = tarval_cmp(l_iv->max, r_iv->min);
+
+                       if (res == ir_relation_less || res == ir_relation_equal)
+                               return tv_true;
+               }
+
+               res = tarval_cmp(l_iv->min, r_iv->max);
+
+               /* [a, b] > [c, d] <==> a > d */
+               if (res == ir_relation_greater)
+                       return tv_false;
+
+               /* if one border is excluded, a >= d is enough */
+               if ((l_iv->flags & MIN_EXCLUDED || r_iv->flags & MAX_EXCLUDED) &&
+                       res == ir_relation_equal)
+                       return tv_false;
+               break;
+
+       case ir_relation_less_equal_greater:
+               /* Hmm. if both are intervals, we can find an order */
+               return tv_true;
+
+       default:
+               return tarval_bad;
+       }
+       return tarval_bad;
 }
 
 /**
  * Returns non-zero, if a given relation is transitive.
  */
-static int is_transitive(pn_Cmp pnc) {
-  return (pn_Cmp_False < pnc && pnc < pn_Cmp_Lg);
+static int is_transitive(ir_relation relation)
+{
+       return (ir_relation_false < relation && relation < ir_relation_less_greater);
 }
 
-
 /**
  * Return the value of a Cmp if one or both predecessors
  * are Confirm nodes.
  *
- * @param cmp    the Cmp node
- * @param left   the left operand of the Cmp
- * @param right  the right operand of the Cmp
- * @param pnc    the compare relation
+ * @param cmp      the Cmp node
+ * @param left     the left operand of the Cmp
+ * @param right    the right operand of the Cmp
+ * @param relation the compare relation
  */
-tarval *computed_value_Cmp_Confirm(ir_node *cmp, ir_node *left, ir_node *right, pn_Cmp pnc)
+ir_tarval *computed_value_Cmp_Confirm(const ir_node *cmp, ir_node *left, ir_node *right, ir_relation relation)
 {
-  ir_node    *l_bound;
-  pn_Cmp     l_pnc, res_pnc, neg_pnc;
-  interval_t l_iv, r_iv;
-  tarval     *tv;
-  ir_mode    *mode;
-
-  if (get_irn_op(right) == op_Confirm) {
-    ir_node *t;
-
-    /* we want the Confirm on the left side */
-    t     = left;
-    left  = right;
-    right = t;
-
-    pnc = get_inversed_pnc(pnc);
-  }
-  else if (get_irn_op(left) != op_Confirm) {
-    /* no Confirm on either one side, finish */
-    return tarval_bad;
-  }
-
-  /* ok, here at least left is a Confirm, right might be */
-  l_bound = get_Confirm_bound(left);
-  l_pnc   = get_Confirm_cmp(left);
-
-  if (get_irn_op(right) == op_Confirm) {
-    /*
-     * both sides are Confirm's. Check some rare cases first.
-     */
-    ir_node *r_bound = get_Confirm_bound(right);
-    pn_Cmp  r_pnc = get_Confirm_cmp(right);
-
-    /*
-     * some check can be made WITHOUT constant bounds
-     */
-    if (r_bound == l_bound) {
-      if (is_transitive(l_pnc)) {
-        pn_Cmp r_inc_pnc = get_inversed_pnc(r_pnc);
-
-        /*
-         * triangle inequality:
-         *
-         * a CMP B && B CMP b => a CMP b, !(a ~CMP b)
-         *
-         * We handle correctly cases with some <=/>= here
-         */
-        if ((l_pnc & ~pn_Cmp_Eq) == (r_inc_pnc & ~pn_Cmp_Eq)) {
-          res_pnc = (l_pnc & ~pn_Cmp_Eq) | (l_pnc & r_inc_pnc & pn_Cmp_Eq);
-
-          if ((pnc == res_pnc) || ((pnc & ~pn_Cmp_Eq) == res_pnc)) {
-            DBG_OUT_TR(l_pnc, l_bound, r_pnc, r_bound, pnc, "true");
-            DBG_EVAL_CONFIRM(cmp);
-            return tarval_b_true;
-          }
-          else {
-            pn_Cmp neg_pnc = get_negated_pnc(pnc, get_irn_mode(left));
-
-            if ((neg_pnc == res_pnc) || ((neg_pnc & ~pn_Cmp_Eq) == res_pnc)) {
-              DBG_OUT_TR(l_pnc, l_bound, r_pnc, r_bound, pnc, "false");
-              DBG_EVAL_CONFIRM(cmp);
-              return tarval_b_false;
-            }
-          }
-        }
-      }
-    }
-
-    /*
-     * Here, we check only the right Confirm, as the left Confirms are
-     * checked later anyway.
-     */
-
-    if (left == r_bound) {
-      /*
-       * l == bound(r) AND pnc(r) == pnc:
-       *
-       * We know that a CMP b and check for that
-       */
-      if ((r_pnc == pnc) || (r_pnc == (pnc & ~pn_Cmp_Eq))) {
-        DBG_OUT_R(r_pnc, r_bound, left, pnc, right, "true");
-        DBG_EVAL_CONFIRM(cmp);
-        return tarval_b_true;
-      }
-      /*
-       * l == bound(r) AND pnc(r) != pnc:
-       *
-       * We know that a CMP b and check for a ~CMP b
-       */
-      else {
-        mode    = get_irn_mode(left);
-        neg_pnc = get_negated_pnc(pnc, mode);
-
-        if ((r_pnc == neg_pnc) || (r_pnc == (neg_pnc & ~pn_Cmp_Eq))) {
-          DBG_OUT_R(r_pnc, r_bound, left, pnc, right, "false");
-          DBG_EVAL_CONFIRM(cmp);
-          return tarval_b_false;
-        }
-      }
-    }
-
-    /* now, try interval magic */
-    tv = compare_iv(
-      get_interval(&l_iv, l_bound, l_pnc),
-      get_interval(&r_iv, r_bound, r_pnc),
-      pnc);
-
-    if (tv != tarval_bad) {
-      DBG_EVAL_CONFIRM(cmp);
-      return tv;
-    }
-  }
-
-  /* from Here, check only left Confirm */
-
-  /*
-   * some checks can be made WITHOUT constant bounds
-   */
-  if (right == l_bound) {
-    /*
-     * r == bound(l) AND pnc(l) == pnc:
-     *
-     * We know that a CMP b and check for that
-     */
-    if ((l_pnc == pnc) || (l_pnc == (pnc & ~pn_Cmp_Eq))) {
-      DBG_OUT_L(l_pnc, l_bound, left, pnc, right, "true");
-      DBG_EVAL_CONFIRM(cmp);
-      return tarval_b_true;
-    }
-    /*
-     * r == bound(l) AND pnc(l) is Not(pnc):
-     *
-     * We know that a CMP b and check for a ~CMP b
-     */
-    else {
-      mode = get_irn_mode(left);
-      neg_pnc = get_negated_pnc(pnc, mode);
-
-      if ((l_pnc == neg_pnc) || (l_pnc == (neg_pnc & ~pn_Cmp_Eq))) {
-        DBG_OUT_L(l_pnc, l_bound, left, pnc, right, "false");
-        DBG_EVAL_CONFIRM(cmp);
-        return tarval_b_false;
-      }
-    }
-  }
-
-  /* now, only right == Const can help */
-  tv = value_of(right);
-
-  if (tv != tarval_bad) {
-    tv = compare_iv(
-      get_interval(&l_iv, l_bound, l_pnc),
-      get_interval_from_tv(&r_iv, tv),
-      pnc);
-  }
-
-  if (tv != tarval_bad)
-    DBG_EVAL_CONFIRM(cmp);
-
-  return tv;
+       ir_node    *l_bound;
+       ir_relation l_relation, res_relation, neg_relation;
+       interval_t  l_iv, r_iv;
+       ir_tarval  *tv;
+
+       if (is_Confirm(right)) {
+               /* we want the Confirm on the left side */
+               ir_node *t = right;
+               right = left;
+               left  = t;
+
+               relation = get_inversed_relation(relation);
+       } else if (! is_Confirm(left)) {
+               /* nothing more found */
+               tv = tarval_bad;
+               goto check_null_case;
+       }
+
+       /* ok, here at least left is a Confirm, right might be */
+       l_bound    = get_Confirm_bound(left);
+       l_relation = get_Confirm_relation(left);
+
+       if (is_Confirm(right)) {
+               /*
+                * both sides are Confirm's. Check some rare cases first.
+                */
+               ir_node    *r_bound    = get_Confirm_bound(right);
+               ir_relation r_relation = get_Confirm_relation(right);
+
+               /*
+                * some check can be made WITHOUT constant bounds
+                */
+               if (r_bound == l_bound) {
+                       if (is_transitive(l_relation)) {
+                               ir_relation r_inc_relation = get_inversed_relation(r_relation);
+
+                               /*
+                                * triangle inequality:
+                                *
+                                * a CMP B && B CMP b => a CMP b, !(a ~CMP b)
+                                *
+                                * We handle correctly cases with some <=/>= here
+                                */
+                               if ((l_relation & ~ir_relation_equal) == (r_inc_relation & ~ir_relation_equal)) {
+                                       res_relation = (l_relation & ~ir_relation_equal) | (l_relation & r_inc_relation & ir_relation_equal);
+
+                                       if ((relation == res_relation) || ((relation & ~ir_relation_equal) == res_relation)) {
+                                               DBG_OUT_TR(l_relation, l_bound, r_relation, r_bound, relation, "true");
+                                               DBG_EVAL_CONFIRM(cmp);
+                                               return tarval_b_true;
+                                       } else {
+                                               ir_relation neg_relation = get_negated_relation(relation);
+
+                                               if ((neg_relation == res_relation) || ((neg_relation & ~ir_relation_equal) == res_relation)) {
+                                                       DBG_OUT_TR(l_relation, l_bound, r_relation, r_bound, relation, "false");
+                                                       DBG_EVAL_CONFIRM(cmp);
+                                                       return tarval_b_false;
+                                               }
+                                       }
+                               }
+                       }
+               }
+
+               /*
+                * Here, we check only the right Confirm, as the left Confirms are
+                * checked later anyway.
+                */
+               if (left == r_bound) {
+                       /*
+                        * l == bound(r) AND relation(r) == relation:
+                        *
+                        * We know that a CMP b and check for that
+                        */
+                       if ((r_relation == relation) || (r_relation == (relation & ~ir_relation_equal))) {
+                               DBG_OUT_R(r_relation, r_bound, left, relation, right, "true");
+                               DBG_EVAL_CONFIRM(cmp);
+                               return tarval_b_true;
+                       }
+                       /*
+                        * l == bound(r) AND relation(r) != relation:
+                        *
+                        * We know that a CMP b and check for a ~CMP b
+                        */
+                       else {
+                               neg_relation = get_negated_relation(relation);
+
+                               if ((r_relation == neg_relation) || (r_relation == (neg_relation & ~ir_relation_equal))) {
+                                       DBG_OUT_R(r_relation, r_bound, left, relation, right, "false");
+                                       DBG_EVAL_CONFIRM(cmp);
+                                       return tarval_b_false;
+                               }
+                       }
+               }
+
+               /* now, try interval magic */
+               tv = compare_iv(
+                       get_interval(&l_iv, l_bound, l_relation),
+                       get_interval(&r_iv, r_bound, r_relation),
+                       relation);
+
+               if (tv != tarval_bad) {
+                       DBG_EVAL_CONFIRM(cmp);
+                       return tv;
+               }
+       }
+
+       /* from Here, check only left Confirm */
+
+       /*
+        * some checks can be made WITHOUT constant bounds
+        */
+       if (right == l_bound) {
+               /*
+                * r == bound(l) AND relation(l) == relation:
+                *
+                * We know that a CMP b and check for that
+                */
+               if ((l_relation == relation) || (l_relation == (relation & ~ir_relation_equal))) {
+                       DBG_OUT_L(l_relation, l_bound, left, relation, right, "true");
+                       DBG_EVAL_CONFIRM(cmp);
+                       return tarval_b_true;
+               }
+               /*
+                * r == bound(l) AND relation(l) is Not(relation):
+                *
+                * We know that a CMP b and check for a ~CMP b
+                */
+               else {
+                       neg_relation = get_negated_relation(relation);
+
+                       if ((l_relation == neg_relation) || (l_relation == (neg_relation & ~ir_relation_equal))) {
+                               DBG_OUT_L(l_relation, l_bound, left, relation, right, "false");
+                               DBG_EVAL_CONFIRM(cmp);
+                               return tarval_b_false;
+                       }
+               }
+       }
+
+       /* now, only right == Const can help */
+       tv = value_of(right);
+
+       if (tv != tarval_bad) {
+               tv = compare_iv(
+                       get_interval(&l_iv, l_bound, l_relation),
+                       get_interval_from_tv(&r_iv, tv),
+                       relation);
+       } else {
+check_null_case:
+               /* check some other cases */
+               if ((relation == ir_relation_equal || relation == ir_relation_less_greater) &&
+                       is_Const(right) && is_Const_null(right)) {
+                       /* for == 0 or != 0 we have some special tools */
+                       ir_mode       *mode = get_irn_mode(left);
+                       const ir_node *dummy;
+                       if (mode_is_reference(mode)) {
+                               if (value_not_null(left, &dummy)) {
+                                       tv = relation == ir_relation_equal ? tarval_b_false : tarval_b_true;
+                               }
+                       } else {
+                               if (value_not_zero(left, &dummy)) {
+                                       tv = relation == ir_relation_equal ? tarval_b_false : tarval_b_true;
+                               }
+                       }
+               }
+       }
+
+       if (tv != tarval_bad)
+               DBG_EVAL_CONFIRM(cmp);
+
+       return tv;
 }
 
 #ifdef DEBUG_CONFIRM
@@ -737,62 +801,62 @@ tarval *computed_value_Cmp_Confirm(ir_node *cmp, ir_node *left, ir_node *right,
  * @param len   length of the string buffer
  * @param iv    the interval
  */
-static int iv_snprintf(char *buf, size_t len, const interval_t *iv) {
-  char smin[64], smax[64];
-
-  if (iv) {
-    tarval_snprintf(smin, sizeof(smin), iv->min);
-
-    if (iv->min != iv->max || (iv->flags & (MIN_EXCLUDED|MAX_EXCLUDED))) {
-      tarval_snprintf(smax, sizeof(smax), iv->max);
-
-      return snprintf(buf, len, "%c%s, %s%c",
-              iv->flags & MIN_EXCLUDED ? '(' : '[',
-              smin, smax,
-              iv->flags & MAX_EXCLUDED ? ')' : ']'
-      );
-    }
-    else
-      return snprintf(buf, len, "%s", smin);
-  }
-  return snprintf(buf, len, "<UNKNOWN>");
+static int iv_snprintf(char *buf, size_t len, const interval_t *iv)
+{
+       char smin[64], smax[64];
+
+       if (iv) {
+               tarval_snprintf(smin, sizeof(smin), iv->min);
+
+               if (iv->min != iv->max || (iv->flags & (MIN_EXCLUDED|MAX_EXCLUDED))) {
+                       tarval_snprintf(smax, sizeof(smax), iv->max);
+
+                       return snprintf(buf, len, "%c%s, %s%c",
+                               iv->flags & MIN_EXCLUDED ? '(' : '[',
+                               smin, smax,
+                               iv->flags & MAX_EXCLUDED ? ')' : ']'
+                               );
+               } else
+                       return snprintf(buf, len, "%s", smin);
+       }
+       return snprintf(buf, len, "<UNKNOWN>");
 }
 
 /**
  * For debugging. Prints an interval compare.
  *
- * @param l_iv  the left interval
- * @param r_iv  the right interval
- * @param pnc   the compare relation
+ * @param l_iv      the left interval
+ * @param r_iv      the right interval
+ * @param relation  the compare relation
  */
-static void print_iv_cmp(const interval_t *l_iv, const interval_t *r_iv, pn_Cmp pnc)
+static void print_iv_cmp(const interval_t *l_iv, const interval_t *r_iv, ir_relation relation)
 {
-  char sl[128], sr[128];
+       char sl[128], sr[128];
 
-  iv_snprintf(sl, sizeof(sl), l_iv);
-  iv_snprintf(sr, sizeof(sr), r_iv);
+       iv_snprintf(sl, sizeof(sl), l_iv);
+       iv_snprintf(sr, sizeof(sr), r_iv);
 
-  ir_printf("%s %= %s", sl, pnc, sr);
+       ir_printf("%s %= %s", sl, relation, sr);
 }
 
 /**
  * For debugging. call *compare_iv() and prints inputs and result.
  *
- * @param l_iv  the left interval
- * @param r_iv  the right interval
- * @param pnc   the compare relation
+ * @param l_iv     the left interval
+ * @param r_iv     the right interval
+ * @param relation the compare relation
  */
-static tarval *compare_iv_dbg(const interval_t *l_iv, const interval_t *r_iv, pn_Cmp pnc)
+static tarval *compare_iv_dbg(const interval_t *l_iv, const interval_t *r_iv, ir_relation relation)
 {
-  tarval *tv = (compare_iv)(l_iv, r_iv, pnc);
+       tarval *tv = (compare_iv)(l_iv, r_iv, relation);
 
-  if (tv == tarval_bad)
-    return tv;
+       if (tv == tarval_bad)
+       return tv;
 
-  ir_printf("In %e:\n", get_irg_entity(current_ir_graph));
-  print_iv_cmp(l_iv, r_iv, pnc);
-  ir_printf(" = %T\n", tv);
-  return tv;
+       ir_printf("In %e:\n", get_irg_entity(current_ir_graph));
+       print_iv_cmp(l_iv, r_iv, relation);
+       ir_printf(" = %T\n", tv);
+       return tv;
 }
 
 #endif /* DEBUG_CONFIRM */