GVN fixes
[libfirm] / ir / opt / opt_confirms.c
index 95df834..dc67eaf 100644 (file)
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 1995-2007 University of Karlsruhe.  All right reserved.
+ * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
  *
  * This file is part of libFirm.
  *
  * @file
  * @brief   Optimizations regarding Confirm nodes.
  * @author  Michael Beck
- * @version $Id$
  */
-#ifdef HAVE_CONFIG_H
-# include "config.h"
-#endif
+#include "config.h"
 
 #undef DEBUG_CONFIRM
 
@@ -33,7 +30,7 @@
 #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"
 
@@ -52,42 +49,42 @@ 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 */
+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 */
 
@@ -97,25 +94,38 @@ 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, ir_node **confirm) {
-#define RET_ON(x)  if (x) { *confirm = n; return 1; }; break
+int value_not_zero(const ir_node *n, const ir_node **confirm)
+{
+#define RET_ON(x)  if (x) { *confirm = n; return 1; } break
 
-       tarval *tv;
+       ir_tarval *tv;
        ir_mode *mode = get_irn_mode(n);
-       pn_Cmp pnc;
+       ir_relation relation;
 
        *confirm = NULL;
-       while (get_irn_op(n) == op_Confirm) {
+
+       /* 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)
-                       return 0;
+               if (tv == tarval_bad) {
+                       n = get_Confirm_value(n);
+                       continue;
+               }
 
-               pnc = tarval_cmp(tv, get_mode_null(mode));
+               relation = tarval_cmp(tv, get_mode_null(mode));
 
                /*
                 * Beware: C might by a NaN. It is not clear, what we should do
@@ -125,35 +135,36 @@ int value_not_zero(ir_node *n, ir_node **confirm) {
                 *
                 * 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);
+               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;
                }
-
-               /* there might be several Confirms one after other that form an interval */
                n = get_Confirm_value(n);
        }
-       tv = value_of(n);
+       /* global entities are never NULL */
+       if (is_SymConst_addr_ent(n))
+               return true;
 
+       tv = value_of(n);
        if (tv == tarval_bad)
-               return 0;
+               return false;
 
-       pnc = tarval_cmp(tv, get_mode_null(mode));
+       relation = tarval_cmp(tv, get_mode_null(mode));
 
        /* again, need check for NaN */
-       return (pnc != pn_Cmp_Eq) && (pnc != pn_Cmp_Uo);
+       return (relation != ir_relation_equal) && (relation != ir_relation_unordered);
 
 #undef RET_ON
 }  /* value_not_zero */
@@ -161,54 +172,94 @@ int value_not_zero(ir_node *n, ir_node **confirm) {
 /*
  * 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.
+ * - Casts are skipped, Sels are skipped
  * - A SymConst(entity) is NEVER a NULL pointer
  * - Confirms are evaluated
  */
-int value_not_null(ir_node *n, ir_node **confirm) {
-       ir_op *op;
+int value_not_null(const ir_node *n, const ir_node **confirm)
+{
+       ir_tarval *tv;
 
        *confirm = NULL;
-       n  = skip_Cast(n);
-       op = get_irn_op(n);
+       n  = skip_Cast_const(n);
+
+       tv = value_of(n);
+       if (tarval_is_constant(tv) && ! tarval_is_null(tv))
+               return 1;
+
        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);
-               }
+       /* skip all Sel nodes and Cast's */
+       while (is_Sel(n)) {
+               n = skip_Cast(get_Sel_ptr(n));
+       }
+       while (1) {
+               if (is_Cast(n)) { n = get_Cast_op(n); continue; }
+               if (is_Proj(n)) { n = get_Proj_pred(n); continue; }
+               break;
        }
-       if (op == op_SymConst && get_SymConst_kind(n) == symconst_addr_ent)
+
+       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;
-       if (op == op_Const) {
-               tarval *tv = get_Const_tarval(n);
-
-               if (tv != tarval_bad && classify_tarval(tv) != TV_CLASSIFY_NULL)
-                       return 1;
-       } else if (op == op_Confirm) {
-               if (get_Confirm_cmp(n) == pn_Cmp_Lg &&
-                       classify_Const(get_Confirm_bound(n)) == CNST_NULL) {
-                               *confirm = n;
-                               return 1;
+       } else {
+               /* check for more Confirms */
+               for (; is_Confirm(n); n = skip_Cast(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;
 }  /* value_not_null */
 
+#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_sign classify_value_sign(ir_node *n) {
-       tarval *tv, *c;
+ir_value_classify_sign classify_value_sign(ir_node *n)
+{
+       ir_tarval *tv, *c;
        ir_mode *mode;
-       pn_Cmp cmp, ncmp;
-
-       if (get_irn_op(n) != op_Confirm)
+       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));
@@ -226,15 +277,15 @@ value_classify_sign classify_value_sign(ir_node *n) {
         * optimization possibilities, so we handle this
         * different.
         */
-       cmp = get_Confirm_cmp(n);
+       cmp = get_Confirm_relation(n);
 
        switch (cmp) {
-       case pn_Cmp_Lt:
+       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 pn_Cmp_Le:
+       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
@@ -243,21 +294,21 @@ value_classify_sign classify_value_sign(ir_node *n) {
                        get_mode_one(mode) : get_mode_null(mode);
 
                ncmp = tarval_cmp(tv, c);
-               if (ncmp == pn_Cmp_Eq)
-                       ncmp = pn_Cmp_Le;
+               if (ncmp == ir_relation_equal)
+                       ncmp = ir_relation_less_equal;
 
-               if (cmp != (ncmp ^ pn_Cmp_Eq))
+               if (cmp != (ncmp ^ ir_relation_equal))
                        return value_classified_unknown;
 
                /* yep, negative */
-               return value_classified_negative;
+               return value_classified_negative * negate;
 
-       case pn_Cmp_Ge:
+       case ir_relation_greater_equal:
                /*
                 * must be x >= c > -1 to be useful if integer mode
                 *         x >= c >= 0 to be useful else
                 */
-       case pn_Cmp_Gt:
+       case ir_relation_greater:
                /*
                 * must be x > c >= -1 to be useful if integer mode
                 *         x > c >= 0 to be useful else
@@ -266,22 +317,22 @@ value_classify_sign classify_value_sign(ir_node *n) {
                        c = get_mode_minus_one(mode);
 
                        ncmp = tarval_cmp(tv, c);
-                       if (ncmp == pn_Cmp_Eq)
-                               ncmp = pn_Cmp_Ge;
+                       if (ncmp == ir_relation_equal)
+                               ncmp = ir_relation_greater_equal;
 
-                       if (cmp != (ncmp ^ pn_Cmp_Eq))
+                       if (cmp != (ncmp ^ ir_relation_equal))
                                return value_classified_unknown;
                } else {
                        c = get_mode_minus_one(mode);
 
                        ncmp = tarval_cmp(tv, c);
 
-                       if (ncmp != pn_Cmp_Eq && ncmp != pn_Cmp_Gt)
+                       if (ncmp != ir_relation_equal && ncmp != ir_relation_greater)
                                return value_classified_unknown;
                }
 
                /* yep, positive */
-               return value_classified_positive;
+               return value_classified_positive * negate;
 
        default:
                return value_classified_unknown;
@@ -294,7 +345,8 @@ value_classify_sign 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) {
@@ -334,16 +386,17 @@ static interval_t *get_interval_from_tv(interval_t *iv, tarval *tv) {
 /**
  * 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) {
-       ir_mode *mode = get_irn_mode(bound);
-       tarval  *tv   = value_of(bound);
+static interval_t *get_interval(interval_t *iv, ir_node *bound, ir_relation relation)
+{
+       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
@@ -369,43 +422,43 @@ static interval_t *get_interval(interval_t *iv, ir_node *bound, pn_Cmp pnc) {
        }
 
        /* check which side is known */
-       switch (pnc) {
-       case pn_Cmp_Eq:
+       switch (relation) {
+       case ir_relation_equal:
                /* [tv, tv] */
                iv->min   =
                        iv->max   = tv;
                iv->flags = MIN_INCLUDED | MAX_INCLUDED;
                break;
 
-       case pn_Cmp_Le:
+       case ir_relation_less_equal:
                /* [-oo, tv] */
                iv->min   = get_mode_min(mode);
                iv->max   = tv;
                iv->flags = MIN_INCLUDED | MAX_INCLUDED;
                break;
 
-       case pn_Cmp_Lt:
+       case ir_relation_less:
                /* [-oo, tv) */
                iv->min   = get_mode_min(mode);
                iv->max   = tv;
                iv->flags = MIN_INCLUDED | MAX_EXCLUDED;
                break;
 
-       case pn_Cmp_Gt:
+       case ir_relation_greater:
                /* (tv, +oo] */
                iv->min   = tv;
                iv->max   = get_mode_max(mode);
                iv->flags = MIN_EXCLUDED | MAX_INCLUDED;
                break;
 
-       case pn_Cmp_Ge:
+       case ir_relation_greater_equal:
                /* [tv, +oo] */
                iv->min   = tv;
                iv->max   = get_mode_max(mode);
                iv->flags = MIN_INCLUDED | MAX_INCLUDED;
                break;
 
-       case pn_Cmp_Leg:
+       case ir_relation_less_equal_greater:
                /*
                 * Ordered means, that at least neither
                 * our bound nor our value ara NaN's
@@ -433,128 +486,129 @@ static interval_t *get_interval(interval_t *iv, ir_node *bound, pn_Cmp pnc) {
 }  /* get_interval */
 
 /**
- * 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) {
-       pn_Cmp res;
-       unsigned flags;
-       tarval *tv_true = tarval_b_true, *tv_false = tarval_b_false;
+static ir_tarval *(compare_iv)(const interval_t *l_iv, const interval_t *r_iv, ir_relation relation)
+{
+       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 (pnc & pn_Cmp_Uo) {
-               tarval *t;
+       if (relation & ir_relation_unordered) {
+               ir_tarval *t;
 
-               pnc      = get_negated_pnc(pnc, get_tarval_mode(l_iv->min));
+               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 (pnc == pn_Cmp_Ge || pnc == pn_Cmp_Gt) {
+       if (relation == ir_relation_greater_equal || relation == ir_relation_greater) {
                const interval_t *t;
 
-               pnc  = get_inversed_pnc(pnc);
-               t    = l_iv;
-               l_iv = r_iv;
-               r_iv = t;
+               relation = get_inversed_relation(relation);
+               t        = l_iv;
+               l_iv     = r_iv;
+               r_iv     = t;
        }
 
        /* now, only the following cases remains */
-       switch (pnc) {
-       case pn_Cmp_Eq:
+       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) == pn_Cmp_Eq ? tv_true : tv_false;
+                       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 == pn_Cmp_Lt)
+               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 == pn_Cmp_Eq))
+                       && (res == ir_relation_equal))
                        return tv_false;
 
                res = tarval_cmp(r_iv->max, l_iv->min);
 
                /* d < a ==> [c,d] != [a,b] */
-               if (res == pn_Cmp_Lt)
+               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 == pn_Cmp_Eq))
+                       && (res == ir_relation_equal))
                        return tv_false;
                break;
 
-       case pn_Cmp_Lg:
+       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) != pn_Cmp_Eq ? tv_true : tv_false;
+                       return tarval_cmp(l_iv->min, r_iv->min) != ir_relation_equal ? tv_true : tv_false;
                break;
 
-       case pn_Cmp_Lt:
+       case ir_relation_less:
                res = tarval_cmp(l_iv->max, r_iv->min);
 
                /* [a, b] < [c, d]  <==> b < c */
-               if (res == pn_Cmp_Lt)
+               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 == pn_Cmp_Eq)
+                       res == ir_relation_equal)
                        return tv_true;
 
                /* [a, b] >= [c, d] <==> a > d */
                res = tarval_cmp(l_iv->min, r_iv->max);
-               if (res == pn_Cmp_Gt)
+               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 == pn_Cmp_Eq)
+                       res == ir_relation_equal)
                        return tv_false;
                break;
 
-       case pn_Cmp_Le:
+       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 == pn_Cmp_Lt || res == pn_Cmp_Eq)
+                       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 == pn_Cmp_Gt)
+               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 == pn_Cmp_Eq)
+                       res == ir_relation_equal)
                        return tv_false;
                break;
 
-       case pn_Cmp_Leg:
+       case ir_relation_less_equal_greater:
                /* Hmm. if both are intervals, we can find an order */
                return tv_true;
 
@@ -567,58 +621,57 @@ static tarval *(compare_iv)(const interval_t *l_iv, const interval_t *r_iv, pn_C
 /**
  * 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);
 }  /* is_transitive */
 
-
 /**
  * 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;
+       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 */
-               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;
+               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_pnc   = get_Confirm_cmp(left);
+       l_bound    = get_Confirm_bound(left);
+       l_relation = get_Confirm_relation(left);
 
-       if (get_irn_op(right) == op_Confirm) {
+       if (is_Confirm(right)) {
                /*
-               * 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);
+                * 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
-               */
+                * 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);
+                       if (is_transitive(l_relation)) {
+                               ir_relation r_inc_relation = get_inversed_relation(r_relation);
 
                                /*
                                 * triangle inequality:
@@ -627,18 +680,18 @@ tarval *computed_value_Cmp_Confirm(ir_node *cmp, ir_node *left, ir_node *right,
                                 *
                                 * 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 ((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 ((pnc == res_pnc) || ((pnc & ~pn_Cmp_Eq) == res_pnc)) {
-                                               DBG_OUT_TR(l_pnc, l_bound, r_pnc, r_bound, pnc, "true");
+                                       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 {
-                                               pn_Cmp neg_pnc = get_negated_pnc(pnc, get_irn_mode(left));
+                                               ir_relation neg_relation = get_negated_relation(relation);
 
-                                               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");
+                                               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;
                                                }
@@ -653,26 +706,25 @@ tarval *computed_value_Cmp_Confirm(ir_node *cmp, ir_node *left, ir_node *right,
                 */
                if (left == r_bound) {
                        /*
-                        * l == bound(r) AND pnc(r) == pnc:
+                        * l == bound(r) AND relation(r) == relation:
                         *
                         * 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");
+                       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 pnc(r) != pnc:
+                        * l == bound(r) AND relation(r) != relation:
                         *
                         * 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);
+                               neg_relation = get_negated_relation(relation);
 
-                               if ((r_pnc == neg_pnc) || (r_pnc == (neg_pnc & ~pn_Cmp_Eq))) {
-                                       DBG_OUT_R(r_pnc, r_bound, left, pnc, right, "false");
+                               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;
                                }
@@ -681,9 +733,9 @@ tarval *computed_value_Cmp_Confirm(ir_node *cmp, ir_node *left, ir_node *right,
 
                /* now, try interval magic */
                tv = compare_iv(
-                       get_interval(&l_iv, l_bound, l_pnc),
-                       get_interval(&r_iv, r_bound, r_pnc),
-                       pnc);
+                       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);
@@ -698,26 +750,25 @@ tarval *computed_value_Cmp_Confirm(ir_node *cmp, ir_node *left, ir_node *right,
         */
        if (right == l_bound) {
                /*
-                * r == bound(l) AND pnc(l) == pnc:
+                * r == bound(l) AND relation(l) == relation:
                 *
                 * 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");
+               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 pnc(l) is Not(pnc):
+                * r == bound(l) AND relation(l) is Not(relation):
                 *
                 * 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);
+                       neg_relation = get_negated_relation(relation);
 
-                       if ((l_pnc == neg_pnc) || (l_pnc == (neg_pnc & ~pn_Cmp_Eq))) {
-                               DBG_OUT_L(l_pnc, l_bound, left, pnc, right, "false");
+                       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;
                        }
@@ -729,9 +780,27 @@ tarval *computed_value_Cmp_Confirm(ir_node *cmp, ir_node *left, ir_node *right,
 
        if (tv != tarval_bad) {
                tv = compare_iv(
-                       get_interval(&l_iv, l_bound, l_pnc),
+                       get_interval(&l_iv, l_bound, l_relation),
                        get_interval_from_tv(&r_iv, tv),
-                       pnc);
+                       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)
@@ -748,7 +817,8 @@ 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) {
+static int iv_snprintf(char *buf, size_t len, const interval_t *iv)
+{
        char smin[64], smax[64];
 
        if (iv) {
@@ -771,34 +841,36 @@ static int iv_snprintf(char *buf, size_t len, const interval_t *iv) {
 /**
  * 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];
 
        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);
 }  /* print_iv_cmp */
 
 /**
  * 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) {
-       tarval *tv = (compare_iv)(l_iv, r_iv, 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, relation);
 
        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);
+       print_iv_cmp(l_iv, r_iv, relation);
        ir_printf(" = %T\n", tv);
        return tv;
 }  /* compare_iv_dbg */