fix more cparser warnings, cleanup some libcore code
[libfirm] / ir / ir / iropt.c
index 84f5079..9f9f0e7 100644 (file)
@@ -131,6 +131,12 @@ static ir_tarval *computed_value_Add(const ir_node *n)
        if ((ta != tarval_bad) && (tb != tarval_bad))
                return tarval_add(ta, tb);
 
+       /* x+~x => -1 */
+       if ((is_Not(a) && get_Not_op(a) == b)
+           || (is_Not(b) && get_Not_op(b) == a)) {
+               return get_mode_all_one(get_irn_mode(n));
+       }
+
        return tarval_bad;
 }  /* computed_value_Add */
 
@@ -264,10 +270,17 @@ static ir_tarval *computed_value_And(const ir_node *n)
 
        if ((ta != tarval_bad) && (tb != tarval_bad)) {
                return tarval_and (ta, tb);
-       } else {
-               if (tarval_is_null(ta)) return ta;
-               if (tarval_is_null(tb)) return tb;
        }
+
+       if (tarval_is_null(ta)) return ta;
+       if (tarval_is_null(tb)) return tb;
+
+       /* x&~x => 0 */
+       if ((is_Not(a) && get_Not_op(a) == b)
+           || (is_Not(b) && get_Not_op(b) == a)) {
+               return get_mode_null(get_irn_mode(n));
+       }
+
        return tarval_bad;
 }  /* computed_value_And */
 
@@ -284,9 +297,15 @@ static ir_tarval *computed_value_Or(const ir_node *n)
 
        if ((ta != tarval_bad) && (tb != tarval_bad)) {
                return tarval_or (ta, tb);
-       } else {
-               if (tarval_is_all_one(ta)) return ta;
-               if (tarval_is_all_one(tb)) return tb;
+       }
+
+       if (tarval_is_all_one(ta)) return ta;
+       if (tarval_is_all_one(tb)) return tb;
+
+       /* x|~x => -1 */
+       if ((is_Not(a) && get_Not_op(a) == b)
+           || (is_Not(b) && get_Not_op(b) == a)) {
+               return get_mode_all_one(get_irn_mode(n));
        }
        return tarval_bad;
 }  /* computed_value_Or */
@@ -303,6 +322,11 @@ static ir_tarval *computed_value_Eor(const ir_node *n)
 
        if (a == b)
                return get_mode_null(get_irn_mode(n));
+       /* x^~x => -1 */
+       if ((is_Not(a) && get_Not_op(a) == b)
+           || (is_Not(b) && get_Not_op(b) == a)) {
+               return get_mode_all_one(get_irn_mode(n));
+       }
 
        ta = value_of(a);
        tb = value_of(b);
@@ -327,6 +351,28 @@ static ir_tarval *computed_value_Not(const ir_node *n)
        return tarval_bad;
 }  /* computed_value_Not */
 
+/**
+ * Tests whether a shift shifts more bits than available in the mode
+ */
+static bool is_oversize_shift(const ir_node *n)
+{
+       ir_node   *count = get_binop_right(n);
+       ir_mode   *mode  = get_irn_mode(n);
+       ir_tarval *tv    = value_of(count);
+       long       modulo_shift;
+       long       shiftval;
+       if (tv == tarval_bad)
+               return false;
+       if (!tarval_is_long(tv))
+               return false;
+       shiftval     = get_tarval_long(tv);
+       modulo_shift = get_mode_modulo_shift(mode);
+       if (shiftval < 0 || (modulo_shift > 0 && shiftval >= modulo_shift))
+               return false;
+
+       return shiftval >= (long)get_mode_size_bits(mode);
+}
+
 /**
  * Return the value of a Shl.
  */
@@ -341,6 +387,10 @@ static ir_tarval *computed_value_Shl(const ir_node *n)
        if ((ta != tarval_bad) && (tb != tarval_bad)) {
                return tarval_shl(ta, tb);
        }
+
+       if (is_oversize_shift(n))
+               return get_mode_null(get_irn_mode(n));
+
        return tarval_bad;
 }  /* computed_value_Shl */
 
@@ -358,6 +408,9 @@ static ir_tarval *computed_value_Shr(const ir_node *n)
        if ((ta != tarval_bad) && (tb != tarval_bad)) {
                return tarval_shr(ta, tb);
        }
+       if (is_oversize_shift(n))
+               return get_mode_null(get_irn_mode(n));
+
        return tarval_bad;
 }  /* computed_value_Shr */
 
@@ -395,17 +448,52 @@ static ir_tarval *computed_value_Rotl(const ir_node *n)
        return tarval_bad;
 }  /* computed_value_Rotl */
 
+bool ir_zero_when_converted(const ir_node *node, ir_mode *dest_mode)
+{
+       ir_mode *mode = get_irn_mode(node);
+       if (get_mode_arithmetic(mode) != irma_twos_complement
+           || get_mode_arithmetic(dest_mode) != irma_twos_complement)
+           return false;
+
+       if (is_Shl(node)) {
+               ir_node *count = get_Shl_right(node);
+               if (is_Const(count)) {
+                       ir_tarval *tv = get_Const_tarval(count);
+                       if (tarval_is_long(tv)) {
+                               long shiftval = get_tarval_long(tv);
+                               long destbits = get_mode_size_bits(dest_mode);
+                               if (shiftval >= destbits
+                                   && shiftval < (long)get_mode_modulo_shift(mode))
+                                       return true;
+                       }
+               }
+       }
+       if (is_And(node)) {
+               ir_node *right = get_And_right(node);
+               if (is_Const(right)) {
+                       ir_tarval *tv     = get_Const_tarval(right);
+                       ir_tarval *conved = tarval_convert_to(tv, dest_mode);
+                       return tarval_is_null(conved);
+               }
+       }
+       return false;
+}
+
 /**
  * Return the value of a Conv.
  */
 static ir_tarval *computed_value_Conv(const ir_node *n)
 {
-       ir_node *a = get_Conv_op(n);
-       ir_tarval *ta = value_of(a);
+       ir_node   *a    = get_Conv_op(n);
+       ir_tarval *ta   = value_of(a);
+       ir_mode   *mode = get_irn_mode(n);
 
        if (ta != tarval_bad)
                return tarval_convert_to(ta, get_irn_mode(n));
 
+       if (ir_zero_when_converted(a, mode))
+               return get_mode_null(mode);
+
        return tarval_bad;
 }  /* computed_value_Conv */
 
@@ -661,141 +749,6 @@ static ir_op_ops *firm_set_default_computed_value(ir_opcode code, ir_op_ops *ops
 #undef CASE
 }  /* firm_set_default_computed_value */
 
-/**
- * Returns a equivalent block for another block.
- * If the block has only one predecessor, this is
- * the equivalent one. If the only predecessor of a block is
- * the block itself, this is a dead block.
- *
- * If both predecessors of a block are the branches of a binary
- * Cond, the equivalent block is Cond's block.
- *
- * If all predecessors of a block are bad or lies in a dead
- * block, the current block is dead as well.
- *
- * Note, that blocks are NEVER turned into Bad's, instead
- * the dead_block flag is set. So, never test for is_Bad(block),
- * always use is_dead_Block(block).
- */
-static ir_node *equivalent_node_Block(ir_node *n)
-{
-       ir_node *oldn = n;
-       int     n_preds;
-       ir_graph *irg;
-
-       /* don't optimize dead or labeled blocks */
-       if (is_Block_dead(n) || has_Block_entity(n))
-               return n;
-
-       n_preds = get_Block_n_cfgpreds(n);
-
-       /* The Block constructor does not call optimize, but mature_immBlock()
-          calls the optimization. */
-       assert(get_Block_matured(n));
-
-       irg = get_irn_irg(n);
-
-       /* Straightening: a single entry Block following a single exit Block
-          can be merged, if it is not the Start block. */
-       /* !!! Beware, all Phi-nodes of n must have been optimized away.
-          This should be true, as the block is matured before optimize is called.
-          But what about Phi-cycles with the Phi0/Id that could not be resolved?
-          Remaining Phi nodes are just Ids. */
-       if (n_preds == 1) {
-               ir_node *pred = skip_Proj(get_Block_cfgpred(n, 0));
-
-               if (is_Jmp(pred)) {
-                       ir_node *predblock = get_nodes_block(pred);
-                       if (predblock == oldn) {
-                               /* Jmp jumps into the block it is in -- deal self cycle. */
-                               n = set_Block_dead(n);
-                               DBG_OPT_DEAD_BLOCK(oldn, n);
-                       } else {
-                               n = predblock;
-                               DBG_OPT_STG(oldn, n);
-                       }
-               } else if (is_Cond(pred)) {
-                       ir_node *predblock = get_nodes_block(pred);
-                       if (predblock == oldn) {
-                               /* Jmp jumps into the block it is in -- deal self cycle. */
-                               n = set_Block_dead(n);
-                               DBG_OPT_DEAD_BLOCK(oldn, n);
-                       }
-               }
-       } else if (n_preds == 2) {
-               /* Test whether Cond jumps twice to this block
-                * The more general case which more than 2 predecessors is handles
-                * in optimize_cf(), we handle only this special case for speed here.
-                */
-               ir_node *a = get_Block_cfgpred(n, 0);
-               ir_node *b = get_Block_cfgpred(n, 1);
-
-               if (is_Proj(a) && is_Proj(b)) {
-                       ir_node *cond = get_Proj_pred(a);
-
-                   if (cond == get_Proj_pred(b) && is_Cond(cond) &&
-                       get_irn_mode(get_Cond_selector(cond)) == mode_b) {
-                               /* Also a single entry Block following a single exit Block.  Phis have
-                                  twice the same operand and will be optimized away. */
-                               n = get_nodes_block(cond);
-                               DBG_OPT_IFSIM1(oldn, a, b, n);
-                       }
-               }
-       } else if (get_opt_unreachable_code() &&
-                  (n != get_irg_start_block(irg)) &&
-                  (n != get_irg_end_block(irg))) {
-               int i;
-
-               /* If all inputs are dead, this block is dead too, except if it is
-                  the start or end block.  This is one step of unreachable code
-                  elimination */
-               for (i = get_Block_n_cfgpreds(n) - 1; i >= 0; --i) {
-                       ir_node *pred = get_Block_cfgpred(n, i);
-                       ir_node *pred_blk;
-
-                       if (is_Bad(pred)) continue;
-                       pred_blk = get_nodes_block(skip_Proj(pred));
-
-                       if (is_Block_dead(pred_blk)) continue;
-
-                       if (pred_blk != n) {
-                               /* really found a living input */
-                               break;
-                       }
-               }
-               if (i < 0) {
-                       n = set_Block_dead(n);
-                       DBG_OPT_DEAD_BLOCK(oldn, n);
-               }
-       }
-
-       return n;
-}  /* equivalent_node_Block */
-
-/**
- * Returns a equivalent node for a Jmp, a Bad :-)
- * Of course this only happens if the Block of the Jmp is dead.
- */
-static ir_node *equivalent_node_Jmp(ir_node *n)
-{
-       ir_node *oldn = n;
-
-       /* unreachable code elimination */
-       if (is_Block_dead(get_nodes_block(n))) {
-               ir_graph *irg = get_irn_irg(n);
-               n = get_irg_bad(irg);
-               DBG_OPT_DEAD_BLOCK(oldn, n);
-       }
-       return n;
-}  /* equivalent_node_Jmp */
-
-/** Raise is handled in the same way as Jmp. */
-#define equivalent_node_Raise   equivalent_node_Jmp
-
-
-/* We do not evaluate Cond here as we replace it by a new node, a Jmp.
-   See transform_node_Proj_Cond(). */
-
 /**
  * Optimize operations that are commutative and have neutral 0,
  * so a op 0 = 0 op a = a.
@@ -1004,7 +957,7 @@ static ir_node *equivalent_node_Sub(ir_node *n)
 
 
 /**
- * Optimize an "self-inverse unary op", ie op(op(n)) = n.
+ * Optimize an "self-inverse unary op", i.e. op(op(n)) = n.
  *
  * @todo
  *   -(-a) == a, but might overflow two times.
@@ -1299,7 +1252,6 @@ static ir_node *equivalent_node_Phi(ir_node *n)
        int i, n_preds;
 
        ir_node *oldn = n;
-       ir_node *block;
        ir_node *first_val = NULL; /* to shutup gcc */
 
        if (!get_opt_optimize() &&
@@ -1308,52 +1260,25 @@ static ir_node *equivalent_node_Phi(ir_node *n)
 
        n_preds = get_Phi_n_preds(n);
 
-       block = get_nodes_block(n);
-       /* Control dead */
-       if (is_Block_dead(block)) {
-               ir_graph *irg = get_irn_irg(n);
-               return get_irg_bad(irg);
-       }
-
-       if (n_preds == 0) return n;           /* Phi of dead Region without predecessors. */
+       /* Phi of dead Region without predecessors. */
+       if (n_preds == 0)
+               return n;
 
        /* Find first non-self-referencing input */
        for (i = 0; i < n_preds; ++i) {
                first_val = get_Phi_pred(n, i);
-               if (   (first_val != n)                            /* not self pointer */
-#if 0
-                   /* BEWARE: when the if is changed to 1, Phis will ignore their Bad
-                    * predecessors. Then, Phi nodes in unreachable code might be removed,
-                    * causing nodes pointing to themselev (Adds for instance).
-                    * This is really bad and causes endless recursion on several
-                    * code pathes, so we do NOT optimize such code.
-                    * This is not that bad as it sounds, optimize_cf() removes bad control flow
-                    * (and bad Phi predecessors), so live code is optimized later.
-                    */
-                       && (! is_Bad(get_Block_cfgpred(block, i)))
-#endif
-                  ) {        /* value not dead */
-                       break;          /* then found first value. */
+               /* not self pointer */
+               if (first_val != n) {
+                       /* then found first value. */
+                       break;
                }
        }
 
-       if (i >= n_preds) {
-               ir_graph *irg = get_irn_irg(n);
-               /* A totally Bad or self-referencing Phi (we didn't break the above loop) */
-               return get_irg_bad(irg);
-       }
-
        /* search for rest of inputs, determine if any of these
        are non-self-referencing */
        while (++i < n_preds) {
                ir_node *scnd_val = get_Phi_pred(n, i);
-               if (   (scnd_val != n)
-                   && (scnd_val != first_val)
-#if 0
-                   /* see above */
-                   && (! is_Bad(get_Block_cfgpred(block, i)))
-#endif
-                       ) {
+               if (scnd_val != n && scnd_val != first_val) {
                        break;
                }
        }
@@ -1366,49 +1291,6 @@ static ir_node *equivalent_node_Phi(ir_node *n)
        return n;
 }  /* equivalent_node_Phi */
 
-/**
- * Several optimizations:
- * - fold Sync-nodes, iff they have only one predecessor except
- *   themselves.
- */
-static ir_node *equivalent_node_Sync(ir_node *n)
-{
-       int arity = get_Sync_n_preds(n);
-       int i;
-
-       for (i = 0; i < arity;) {
-               ir_node *pred = get_Sync_pred(n, i);
-               int      j;
-
-               /* Remove Bad predecessors */
-               if (is_Bad(pred)) {
-                       del_Sync_n(n, i);
-                       --arity;
-                       continue;
-               }
-
-               /* Remove duplicate predecessors */
-               for (j = 0;; ++j) {
-                       if (j >= i) {
-                               ++i;
-                               break;
-                       }
-                       if (get_Sync_pred(n, j) == pred) {
-                               del_Sync_n(n, i);
-                               --arity;
-                               break;
-                       }
-               }
-       }
-
-       if (arity == 0) {
-               ir_graph *irg = get_irn_irg(n);
-               return get_irg_bad(irg);
-       }
-       if (arity == 1) return get_Sync_pred(n, 0);
-       return n;
-}  /* equivalent_node_Sync */
-
 /**
  * Optimize Proj(Tuple).
  */
@@ -1473,13 +1355,6 @@ static ir_node *equivalent_node_Proj_CopyB(ir_node *proj)
                        proj = get_CopyB_mem(copyb);
                        DBG_OPT_ALGSIM0(oldn, proj, FS_OPT_NOP);
                        break;
-
-               case pn_CopyB_X_except: {
-                       ir_graph *irg = get_irn_irg(proj);
-                       DBG_OPT_EXC_REM(proj);
-                       proj = get_irg_bad(irg);
-                       break;
-               }
                }
        }
        return proj;
@@ -1523,12 +1398,6 @@ static ir_node *equivalent_node_Proj_Bound(ir_node *proj)
                        DBG_OPT_EXC_REM(proj);
                        proj = get_Bound_mem(bound);
                        break;
-               case pn_Bound_X_except: {
-                       ir_graph *irg = get_irn_irg(proj);
-                       DBG_OPT_EXC_REM(proj);
-                       proj = get_irg_bad(irg);
-                       break;
-               }
                case pn_Bound_res:
                        proj = idx;
                        DBG_OPT_ALGSIM0(oldn, proj, FS_OPT_NOP);
@@ -1541,56 +1410,6 @@ static ir_node *equivalent_node_Proj_Bound(ir_node *proj)
        return proj;
 }  /* equivalent_node_Proj_Bound */
 
-/**
- * Optimize an Exception Proj(Load) with a non-null address.
- */
-static ir_node *equivalent_node_Proj_Load(ir_node *proj)
-{
-       if (get_opt_ldst_only_null_ptr_exceptions()) {
-               if (get_irn_mode(proj) == mode_X) {
-                       ir_node *load = get_Proj_pred(proj);
-
-                       /* get the Load address */
-                       const ir_node *addr = get_Load_ptr(load);
-                       const ir_node *confirm;
-
-                       if (value_not_null(addr, &confirm)) {
-                               if (get_Proj_proj(proj) == pn_Load_X_except) {
-                                       ir_graph *irg = get_irn_irg(proj);
-                                       DBG_OPT_EXC_REM(proj);
-                                       return get_irg_bad(irg);
-                               }
-                       }
-               }
-       }
-       return proj;
-}  /* equivalent_node_Proj_Load */
-
-/**
- * Optimize an Exception Proj(Store) with a non-null address.
- */
-static ir_node *equivalent_node_Proj_Store(ir_node *proj)
-{
-       if (get_opt_ldst_only_null_ptr_exceptions()) {
-               if (get_irn_mode(proj) == mode_X) {
-                       ir_node *store = get_Proj_pred(proj);
-
-                       /* get the load/store address */
-                       const ir_node *addr = get_Store_ptr(store);
-                       const ir_node *confirm;
-
-                       if (value_not_null(addr, &confirm)) {
-                               if (get_Proj_proj(proj) == pn_Store_X_except) {
-                                       ir_graph *irg = get_irn_irg(proj);
-                                       DBG_OPT_EXC_REM(proj);
-                                       return get_irg_bad(irg);
-                               }
-                       }
-               }
-       }
-       return proj;
-}  /* equivalent_node_Proj_Store */
-
 /**
  * Does all optimizations on nodes that must be done on its Projs
  * because of creating new nodes.
@@ -1598,14 +1417,6 @@ static ir_node *equivalent_node_Proj_Store(ir_node *proj)
 static ir_node *equivalent_node_Proj(ir_node *proj)
 {
        ir_node *n = get_Proj_pred(proj);
-
-       if (get_irn_mode(proj) == mode_X) {
-               if (is_Block_dead(get_nodes_block(n))) {
-                       /* Remove dead control flow -- early gigo(). */
-                       ir_graph *irg = get_irn_irg(proj);
-                       return get_irg_bad(irg);
-               }
-       }
        if (n->op->ops.equivalent_node_Proj)
                return n->op->ops.equivalent_node_Proj(proj);
        return proj;
@@ -1784,9 +1595,6 @@ static ir_op_ops *firm_set_default_equivalent_node(ir_opcode code, ir_op_ops *op
                break
 
        switch (code) {
-       CASE(Block);
-       CASE(Jmp);
-       CASE(Raise);
        CASE(Eor);
        CASE(Add);
        CASE(Shl);
@@ -1801,13 +1609,10 @@ static ir_op_ops *firm_set_default_equivalent_node(ir_opcode code, ir_op_ops *op
        CASE(And);
        CASE(Conv);
        CASE(Phi);
-       CASE(Sync);
        CASE_PROJ(Tuple);
        CASE_PROJ(Div);
        CASE_PROJ(CopyB);
        CASE_PROJ(Bound);
-       CASE_PROJ(Load);
-       CASE_PROJ(Store);
        CASE(Proj);
        CASE(Id);
        CASE(Mux);
@@ -2235,22 +2040,6 @@ static ir_node *transform_node_Add(ir_node *n)
                                        DBG_OPT_ALGSIM0(oldn, n, FS_OPT_NOT_PLUS_1);
                                        return n;
                                }
-                               if (op == b) {
-                                       /* ~x + x = -1 */
-                                       n = new_r_Const(irg, get_mode_minus_one(mode));
-                                       DBG_OPT_ALGSIM0(oldn, n, FS_OPT_ADD_X_NOT_X);
-                                       return n;
-                               }
-                       }
-                       if (is_Not(b)) {
-                               ir_node *op = get_Not_op(b);
-
-                               if (op == a) {
-                                       /* x + ~x = -1 */
-                                       n = new_r_Const(irg, get_mode_minus_one(mode));
-                                       DBG_OPT_ALGSIM0(oldn, n, FS_OPT_ADD_X_NOT_X);
-                                       return n;
-                               }
                        }
                }
        }
@@ -2259,9 +2048,9 @@ static ir_node *transform_node_Add(ir_node *n)
        b_vrp = vrp_get_info(b);
 
        if (a_vrp && b_vrp) {
-               ir_tarval *c = tarval_and(a_vrp->bits_not_set, b_vrp->bits_not_set);
+               ir_tarval *vrp_val = tarval_and(a_vrp->bits_not_set, b_vrp->bits_not_set);
 
-               if (tarval_is_null(c)) {
+               if (tarval_is_null(vrp_val)) {
                        dbg_info *dbgi  = get_irn_dbg_info(n);
                        return new_rd_Or(dbgi, get_nodes_block(n), a, b, mode);
                }
@@ -2392,6 +2181,7 @@ restart:
                }
                DBG_OPT_ALGSIM0(oldn, n, FS_OPT_SUB_TO_ADD);
                return n;
+#if 0
        } else if (is_Mul(b)) { /* a - (b * C) -> a + (b * -C) */
                ir_node *m_right = get_Mul_right(b);
                if (is_Const(m_right)) {
@@ -2410,6 +2200,7 @@ restart:
                                return n;
                        }
                }
+#endif
        }
 
        /* Beware of Sub(P, P) which cannot be optimized into a simple Minus ... */
@@ -2571,8 +2362,8 @@ restart:
        }
 
        if (get_mode_arithmetic(mode) == irma_twos_complement) {
+               /* c - ~X = X + (c+1) */
                if (is_Const(a) && is_Not(b)) {
-                       /* c - ~X = X + (c+1) */
                        ir_tarval *tv = get_Const_tarval(a);
 
                        tv = tarval_add(tv, get_mode_one(mode));
@@ -2585,6 +2376,24 @@ restart:
                                return n;
                        }
                }
+               /* x-(x&y) = x & ~y */
+               if (is_And(b)) {
+                       ir_node *and_left  = get_And_left(b);
+                       ir_node *and_right = get_And_right(b);
+                       if (and_right == a) {
+                               ir_node *tmp = and_left;
+                               and_left  = and_right;
+                               and_right = tmp;
+                       }
+                       if (and_left == a) {
+                               dbg_info *dbgi  = get_irn_dbg_info(n);
+                               ir_node  *block = get_nodes_block(n);
+                               ir_mode  *mode  = get_irn_mode(n);
+                               ir_node  *notn  = new_rd_Not(dbgi, block, and_right, mode);
+                               ir_node  *and   = new_rd_And(dbgi, block, a, notn, mode);
+                               return and;
+                       }
+               }
        }
        return n;
 }  /* transform_node_Sub */
@@ -2856,10 +2665,10 @@ make_tuple:
 
                /* skip a potential Pin */
                mem = skip_Pin(mem);
-               turn_into_tuple(n, pn_Div_max);
+               turn_into_tuple(n, pn_Div_max+1);
                set_Tuple_pred(n, pn_Div_M,         mem);
                set_Tuple_pred(n, pn_Div_X_regular, new_r_Jmp(blk));
-               set_Tuple_pred(n, pn_Div_X_except,  get_irg_bad(irg));
+               set_Tuple_pred(n, pn_Div_X_except,  new_r_Bad(irg, mode_X));
                set_Tuple_pred(n, pn_Div_res,       value);
        }
        return n;
@@ -2948,10 +2757,10 @@ make_tuple:
 
                /* skip a potential Pin */
                mem = skip_Pin(mem);
-               turn_into_tuple(n, pn_Mod_max);
+               turn_into_tuple(n, pn_Mod_max+1);
                set_Tuple_pred(n, pn_Mod_M,         mem);
                set_Tuple_pred(n, pn_Mod_X_regular, new_r_Jmp(blk));
-               set_Tuple_pred(n, pn_Mod_X_except,  get_irg_bad(irg));
+               set_Tuple_pred(n, pn_Mod_X_except,  new_r_Bad(irg, mode_X));
                set_Tuple_pred(n, pn_Mod_res,       value);
        }
        return n;
@@ -2982,13 +2791,13 @@ static ir_node *transform_node_Cond(ir_node *n)
                   Replace it by a tuple (Bad, Jmp) or (Jmp, Bad) */
                ir_node *blk = get_nodes_block(n);
                jmp = new_r_Jmp(blk);
-               turn_into_tuple(n, pn_Cond_max);
+               turn_into_tuple(n, pn_Cond_max+1);
                if (ta == tarval_b_true) {
-                       set_Tuple_pred(n, pn_Cond_false, get_irg_bad(irg));
+                       set_Tuple_pred(n, pn_Cond_false, new_r_Bad(irg, mode_X));
                        set_Tuple_pred(n, pn_Cond_true, jmp);
                } else {
                        set_Tuple_pred(n, pn_Cond_false, jmp);
-                       set_Tuple_pred(n, pn_Cond_true, get_irg_bad(irg));
+                       set_Tuple_pred(n, pn_Cond_true, new_r_Bad(irg, mode_X));
                }
                /* We might generate an endless loop, so keep it alive. */
                add_End_keepalive(get_irg_end(irg), blk);
@@ -3118,48 +2927,229 @@ static ir_node *create_zero_const(ir_graph *irg, ir_mode *mode)
        return cnst;
 }
 
+static bool is_shiftop(const ir_node *n)
+{
+       return is_Shl(n) || is_Shr(n) || is_Shrs(n) || is_Rotl(n);
+}
+
 /**
- * Transform an And.
+ * normalisation: (x & c1) >> c2   to   (x >> c2) & (c1 >> c2)
+ *  (we can use:
+ *    - and, or, xor          instead of &
+ *    - Shl, Shr, Shrs, rotl  instead of >>
+ *    (with a special case for Or/Xor + Shrs)
+ *
+ * This normalisation is good for things like x-(x&y) esp. in 186.crafty.
  */
-static ir_node *transform_node_And(ir_node *n)
+static ir_node *transform_node_shift_bitop(ir_node *n)
 {
-       ir_node *c, *oldn = n;
-       ir_node *a = get_And_left(n);
-       ir_node *b = get_And_right(n);
-       ir_mode *mode;
-       vrp_attr *a_vrp, *b_vrp;
+       ir_graph  *irg   = get_irn_irg(n);
+       ir_node   *right = get_binop_right(n);
+       ir_mode   *mode  = get_irn_mode(n);
+       ir_node   *left;
+       ir_node   *bitop_left;
+       ir_node   *bitop_right;
+       ir_op     *op_left;
+       ir_node   *block;
+       dbg_info  *dbgi;
+       ir_node   *new_shift;
+       ir_node   *new_bitop;
+       ir_node   *new_const;
+       ir_tarval *tv1;
+       ir_tarval *tv2;
+       ir_tarval *tv_shift;
 
-       if (is_Cmp(a) && is_Cmp(b)) {
-               ir_node    *a_left     = get_Cmp_left(a);
-               ir_node    *a_right    = get_Cmp_right(a);
-               ir_node    *b_left     = get_Cmp_left(b);
-               ir_node    *b_right    = get_Cmp_right(b);
-               ir_relation a_relation = get_Cmp_relation(a);
-               ir_relation b_relation = get_Cmp_relation(b);
-               /* we can combine the relations of two compares with the same
-                * operands */
-               if (a_left == b_left && b_left == b_right) {
-                       dbg_info   *dbgi         = get_irn_dbg_info(n);
-                       ir_node    *block        = get_nodes_block(n);
-                       ir_relation new_relation = a_relation & b_relation;
-                       return new_rd_Cmp(dbgi, block, a_left, a_right, new_relation);
-               }
-               /* Cmp(a==0) and Cmp(b==0) can be optimized to Cmp(a|b==0) */
-               if (is_Const(a_right) && is_Const_null(a_right)
-                               && is_Const(b_right) && is_Const_null(b_right)
-                               && a_relation == b_relation && a_relation == ir_relation_equal
-                               && !mode_is_float(get_irn_mode(a_left))
-                               && !mode_is_float(get_irn_mode(b_left))) {
-                       dbg_info *dbgi     = get_irn_dbg_info(n);
-                       ir_node  *block    = get_nodes_block(n);
-                       ir_mode  *mode     = get_irn_mode(a_left);
-                       ir_node  *n_b_left = get_irn_mode(b_left) != mode ?
-                               new_rd_Conv(dbgi, block, b_left, mode) : b_left;
-                       ir_node  *or       = new_rd_Or(dbgi, block, a_left, n_b_left, mode);
-                       ir_graph *irg      = get_irn_irg(n);
-                       ir_node  *zero     = create_zero_const(irg, mode);
-                       return new_rd_Cmp(dbgi, block, or, zero, ir_relation_equal);
-               }
+       if (is_irg_state(irg, IR_GRAPH_STATE_NORMALISATION2))
+               return n;
+
+       assert(is_Shrs(n) || is_Shr(n) || is_Shl(n) || is_Rotl(n));
+
+       if (!is_Const(right))
+               return n;
+
+       left    = get_binop_left(n);
+       op_left = get_irn_op(left);
+       if (op_left != op_And && op_left != op_Or && op_left != op_Eor)
+               return n;
+
+       /* doing it with Shrs is not legal if the Or/Eor affects the topmost bit */
+       if (is_Shrs(n) && (op_left == op_Or || op_left == op_Eor)) {
+               /* TODO: test if sign bit is affectes */
+               return n;
+       }
+
+       bitop_right = get_binop_right(left);
+       if (!is_Const(bitop_right))
+               return n;
+
+       bitop_left = get_binop_left(left);
+
+       block = get_nodes_block(n);
+       dbgi  = get_irn_dbg_info(n);
+       tv1   = get_Const_tarval(bitop_right);
+       tv2   = get_Const_tarval(right);
+
+       assert(get_tarval_mode(tv1) == mode);
+
+       if (is_Shl(n)) {
+               new_shift = new_rd_Shl(dbgi, block, bitop_left, right, mode);
+               tv_shift  = tarval_shl(tv1, tv2);
+       } else if (is_Shr(n)) {
+               new_shift = new_rd_Shr(dbgi, block, bitop_left, right, mode);
+               tv_shift  = tarval_shr(tv1, tv2);
+       } else if (is_Shrs(n)) {
+               new_shift = new_rd_Shrs(dbgi, block, bitop_left, right, mode);
+               tv_shift  = tarval_shrs(tv1, tv2);
+       } else {
+               assert(is_Rotl(n));
+               new_shift = new_rd_Rotl(dbgi, block, bitop_left, right, mode);
+               tv_shift  = tarval_rotl(tv1, tv2);
+       }
+
+       assert(get_tarval_mode(tv_shift) == mode);
+       irg       = get_irn_irg(n);
+       new_const = new_r_Const(irg, tv_shift);
+
+       if (op_left == op_And) {
+               new_bitop = new_rd_And(dbgi, block, new_shift, new_const, mode);
+       } else if (op_left == op_Or) {
+               new_bitop = new_rd_Or(dbgi, block, new_shift, new_const, mode);
+       } else {
+               assert(op_left == op_Eor);
+               new_bitop = new_rd_Eor(dbgi, block, new_shift, new_const, mode);
+       }
+
+       return new_bitop;
+}
+
+/**
+ * normalisation: (x >> c1) & c2   to   (x & (c2<<c1)) >> c1
+ *  (we can use:
+ *    - and, or, xor          instead of &
+ *    - Shl, Shr, Shrs, rotl  instead of >>
+ *    (with a special case for Or/Xor + Shrs)
+ *
+ * This normalisation is usually good for the backend since << C can often be
+ * matched as address-mode.
+ */
+static ir_node *transform_node_bitop_shift(ir_node *n)
+{
+       ir_graph  *irg   = get_irn_irg(n);
+       ir_node   *left  = get_binop_left(n);
+       ir_node   *right = get_binop_right(n);
+       ir_mode   *mode  = get_irn_mode(n);
+       ir_node   *shift_left;
+       ir_node   *shift_right;
+       ir_node   *block;
+       dbg_info  *dbg_bitop;
+       dbg_info  *dbg_shift;
+       ir_node   *new_bitop;
+       ir_node   *new_shift;
+       ir_node   *new_const;
+       ir_tarval *tv1;
+       ir_tarval *tv2;
+       ir_tarval *tv_bitop;
+
+       if (!is_irg_state(irg, IR_GRAPH_STATE_NORMALISATION2))
+               return n;
+
+       assert(is_And(n) || is_Or(n) || is_Eor(n));
+       if (!is_Const(right) || !is_shiftop(left))
+               return n;
+
+       shift_left  = get_binop_left(left);
+       shift_right = get_binop_right(left);
+       if (!is_Const(shift_right))
+               return n;
+
+       /* doing it with Shrs is not legal if the Or/Eor affects the topmost bit */
+       if (is_Shrs(left)) {
+               /* TODO this could be improved */
+               return n;
+       }
+
+       irg       = get_irn_irg(n);
+       block     = get_nodes_block(n);
+       dbg_bitop = get_irn_dbg_info(n);
+       dbg_shift = get_irn_dbg_info(left);
+       tv1       = get_Const_tarval(shift_right);
+       tv2       = get_Const_tarval(right);
+       assert(get_tarval_mode(tv2) == mode);
+
+       if (is_Shl(left)) {
+               tv_bitop = tarval_shr(tv2, tv1);
+       } else if (is_Shr(left)) {
+               tv_bitop = tarval_shl(tv2, tv1);
+       } else {
+               assert(is_Rotl(left));
+               tv_bitop = tarval_rotl(tv2, tarval_neg(tv1));
+       }
+       new_const = new_r_Const(irg, tv_bitop);
+
+       if (is_And(n)) {
+               new_bitop = new_rd_And(dbg_bitop, block, shift_left, new_const, mode);
+       } else if (is_Or(n)) {
+               new_bitop = new_rd_Or(dbg_bitop, block, shift_left, new_const, mode);
+       } else {
+               assert(is_Eor(n));
+               new_bitop = new_rd_Eor(dbg_bitop, block, shift_left, new_const, mode);
+       }
+
+       if (is_Shl(left)) {
+               new_shift = new_rd_Shl(dbg_shift, block, new_bitop, shift_right, mode);
+       } else if (is_Shr(left)) {
+               new_shift = new_rd_Shr(dbg_shift, block, new_bitop, shift_right, mode);
+       } else {
+               assert(is_Rotl(left));
+               new_shift = new_rd_Rotl(dbg_shift, block, new_bitop, shift_right, mode);
+       }
+
+       return new_shift;
+}
+
+/**
+ * Transform an And.
+ */
+static ir_node *transform_node_And(ir_node *n)
+{
+       ir_node *c, *oldn = n;
+       ir_node *a = get_And_left(n);
+       ir_node *b = get_And_right(n);
+       ir_mode *mode;
+       vrp_attr *a_vrp, *b_vrp;
+
+       if (is_Cmp(a) && is_Cmp(b)) {
+               ir_node    *a_left     = get_Cmp_left(a);
+               ir_node    *a_right    = get_Cmp_right(a);
+               ir_node    *b_left     = get_Cmp_left(b);
+               ir_node    *b_right    = get_Cmp_right(b);
+               ir_relation a_relation = get_Cmp_relation(a);
+               ir_relation b_relation = get_Cmp_relation(b);
+               /* we can combine the relations of two compares with the same
+                * operands */
+               if (a_left == b_left && b_left == b_right) {
+                       dbg_info   *dbgi         = get_irn_dbg_info(n);
+                       ir_node    *block        = get_nodes_block(n);
+                       ir_relation new_relation = a_relation & b_relation;
+                       return new_rd_Cmp(dbgi, block, a_left, a_right, new_relation);
+               }
+               /* Cmp(a==b) and Cmp(c==d) can be optimized to Cmp((a^b)|(c^d)==0) */
+               if (a_relation == b_relation && a_relation == ir_relation_equal
+                   && !mode_is_float(get_irn_mode(a_left))
+                   && !mode_is_float(get_irn_mode(b_left))
+                   && values_in_mode(get_irn_mode(a_left), get_irn_mode(b_left))) {
+                       dbg_info *dbgi   = get_irn_dbg_info(n);
+                       ir_node  *block  = get_nodes_block(n);
+                       ir_mode  *a_mode = get_irn_mode(a_left);
+                       ir_mode  *b_mode = get_irn_mode(b_left);
+                       ir_node  *xora   = new_rd_Eor(dbgi, block, a_left, a_right, a_mode);
+                       ir_node  *xorb   = new_rd_Eor(dbgi, block, b_left, b_right, b_mode);
+                       ir_node  *conv   = new_rd_Conv(dbgi, block, xorb, a_mode);
+                       ir_node  *or     = new_rd_Or(dbgi, block, xora, conv, a_mode);
+                       ir_graph *irg    = get_irn_irg(n);
+                       ir_node  *zero   = create_zero_const(irg, a_mode);
+                       return new_rd_Cmp(dbgi, block, or, zero, ir_relation_equal);
+               }
        }
 
        mode = get_irn_mode(n);
@@ -3281,6 +3271,8 @@ static ir_node *transform_node_And(ir_node *n)
        }
 
        n = transform_bitwise_distributive(n, transform_node_And);
+       if (is_And(n))
+               n = transform_node_bitop_shift(n);
 
        return n;
 }  /* transform_node_And */
@@ -3367,6 +3359,9 @@ static ir_node *transform_node_Eor(ir_node *n)
        }
 
        n = transform_bitwise_distributive(n, transform_node_Eor);
+       if (is_Eor(n))
+               n = transform_node_bitop_shift(n);
+
        return n;
 }  /* transform_node_Eor */
 
@@ -3542,7 +3537,7 @@ static ir_node *transform_node_Proj_Load(ir_node *proj)
                                if (get_Proj_proj(proj) == pn_Load_X_except) {
                                        ir_graph *irg = get_irn_irg(proj);
                                        DBG_OPT_EXC_REM(proj);
-                                       return get_irg_bad(irg);
+                                       return new_r_Bad(irg, mode_X);
                                } else {
                                        ir_node *blk = get_nodes_block(load);
                                        return new_r_Jmp(blk);
@@ -3574,7 +3569,7 @@ static ir_node *transform_node_Proj_Store(ir_node *proj)
                                if (get_Proj_proj(proj) == pn_Store_X_except) {
                                        ir_graph *irg = get_irn_irg(proj);
                                        DBG_OPT_EXC_REM(proj);
-                                       return get_irg_bad(irg);
+                                       return new_r_Bad(irg, mode_X);
                                } else {
                                        ir_node *blk = get_nodes_block(store);
                                        return new_r_Jmp(blk);
@@ -3616,7 +3611,7 @@ static ir_node *transform_node_Proj_Div(ir_node *proj)
                        ir_graph *irg = get_irn_irg(proj);
                        /* we found an exception handler, remove it */
                        DBG_OPT_EXC_REM(proj);
-                       return get_irg_bad(irg);
+                       return new_r_Bad(irg, mode_X);
                }
 
                case pn_Div_M: {
@@ -3671,7 +3666,7 @@ static ir_node *transform_node_Proj_Mod(ir_node *proj)
                        ir_graph *irg = get_irn_irg(proj);
                        /* we found an exception handler, remove it */
                        DBG_OPT_EXC_REM(proj);
-                       return get_irg_bad(irg);
+                       return new_r_Bad(irg, mode_X);
                }
 
                case pn_Mod_M: {
@@ -3728,7 +3723,7 @@ static ir_node *transform_node_Proj_Cond(ir_node *proj)
                                } else {
                                        ir_graph *irg = get_irn_irg(proj);
                                        /* this case will NEVER be taken, kill it */
-                                       return get_irg_bad(irg);
+                                       return new_r_Bad(irg, mode_X);
                                }
                        }
                } else {
@@ -3742,19 +3737,19 @@ static ir_node *transform_node_Proj_Cond(ir_node *proj)
                                        ir_relation cmp_result = tarval_cmp(b_vrp->range_bottom, tp);
                                        ir_relation cmp_result2 = tarval_cmp(b_vrp->range_top, tp);
 
-                                       if ((cmp_result & ir_relation_greater) == cmp_result && (cmp_result2
-                                                               & ir_relation_less) == cmp_result2) {
+                                       if ((cmp_result & ir_relation_greater) == cmp_result
+                                           && (cmp_result2 & ir_relation_less) == cmp_result2) {
                                                ir_graph *irg = get_irn_irg(proj);
-                                               return get_irg_bad(irg);
+                                               return new_r_Bad(irg, mode_X);
                                        }
                                } else if (b_vrp->range_type == VRP_ANTIRANGE) {
                                        ir_relation cmp_result = tarval_cmp(b_vrp->range_bottom, tp);
                                        ir_relation cmp_result2 = tarval_cmp(b_vrp->range_top, tp);
 
-                                       if ((cmp_result & ir_relation_less_equal) == cmp_result && (cmp_result2
-                                                               & ir_relation_greater_equal) == cmp_result2) {
+                                       if ((cmp_result & ir_relation_less_equal) == cmp_result
+                                            && (cmp_result2 & ir_relation_greater_equal) == cmp_result2) {
                                                ir_graph *irg = get_irn_irg(proj);
-                                               return get_irg_bad(irg);
+                                               return new_r_Bad(irg, mode_X);
                                        }
                                }
 
@@ -3763,7 +3758,7 @@ static ir_node *transform_node_Proj_Cond(ir_node *proj)
                                                                b_vrp->bits_set
                                                                ) == ir_relation_equal)) {
                                        ir_graph *irg = get_irn_irg(proj);
-                                       return get_irg_bad(irg);
+                                       return new_r_Bad(irg, mode_X);
                                }
 
                                if (!(tarval_cmp(
@@ -3773,10 +3768,8 @@ static ir_node *transform_node_Proj_Cond(ir_node *proj)
                                                                tarval_not(b_vrp->bits_not_set))
                                                                 == ir_relation_equal)) {
                                        ir_graph *irg = get_irn_irg(proj);
-                                       return get_irg_bad(irg);
+                                       return new_r_Bad(irg, mode_X);
                                }
-
-
                        }
                }
        }
@@ -3827,30 +3820,51 @@ static ir_node *transform_node_Cmp(ir_node *n)
        }
 
        /* Remove unnecessary conversions */
-       /* TODO handle conv+constant */
        if (is_Conv(left) && is_Conv(right)) {
-               ir_node *op_left     = get_Conv_op(left);
-               ir_node *op_right    = get_Conv_op(right);
-               ir_mode *mode_left   = get_irn_mode(op_left);
-               ir_mode *mode_right  = get_irn_mode(op_right);
+               ir_node *op_left    = get_Conv_op(left);
+               ir_node *op_right   = get_Conv_op(right);
+               ir_mode *mode_left  = get_irn_mode(op_left);
+               ir_mode *mode_right = get_irn_mode(op_right);
 
                if (smaller_mode(mode_left, mode) && smaller_mode(mode_right, mode)
                                && mode_left != mode_b && mode_right != mode_b) {
-                       ir_node  *block = get_nodes_block(n);
+                       ir_node *block = get_nodes_block(n);
 
                        if (mode_left == mode_right) {
-                               left  = op_left;
-                               right = op_right;
+                               left    = op_left;
+                               right   = op_right;
                                changed = true;
                                DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_CONV_CONV);
                        } else if (smaller_mode(mode_left, mode_right)) {
-                               left  = new_r_Conv(block, op_left, mode_right);
-                               right = op_right;
+                               left    = new_r_Conv(block, op_left, mode_right);
+                               right   = op_right;
                                changed = true;
                                DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_CONV);
                        } else if (smaller_mode(mode_right, mode_left)) {
-                               left  = op_left;
-                               right = new_r_Conv(block, op_right, mode_left);
+                               left    = op_left;
+                               right   = new_r_Conv(block, op_right, mode_left);
+                               changed = true;
+                               DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_CONV);
+                       }
+                       mode = get_irn_mode(left);
+               }
+       }
+       if (is_Conv(left) && is_Const(right)) {
+               ir_node   *op_left   = get_Conv_op(left);
+               ir_mode   *mode_left = get_irn_mode(op_left);
+               if (smaller_mode(mode_left, mode) && mode_left != mode_b) {
+                       ir_tarval *tv        = get_Const_tarval(right);
+                       tarval_int_overflow_mode_t last_mode
+                               = tarval_get_integer_overflow_mode();
+                       ir_tarval *new_tv;
+                       tarval_set_integer_overflow_mode(TV_OVERFLOW_BAD);
+                       new_tv = tarval_convert_to(tv, mode_left);
+                       tarval_set_integer_overflow_mode(last_mode);
+                       if (new_tv != tarval_bad) {
+                               ir_graph *irg = get_irn_irg(n);
+                               left    = op_left;
+                               right   = new_r_Const(irg, new_tv);
+                               mode    = get_irn_mode(left);
                                changed = true;
                                DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_CONV);
                        }
@@ -4192,19 +4206,6 @@ static ir_node *transform_node_Cmp(ir_node *n)
 
                                /* the following reassociations work only for == and != */
                                if (relation == ir_relation_equal || relation == ir_relation_less_greater) {
-
-#if 0 /* Might be not that good in general */
-                                       /* a-b == 0  ==>  a == b,  a-b != 0  ==>  a != b */
-                                       if (tarval_is_null(tv) && is_Sub(left)) {
-                                               right = get_Sub_right(left);
-                                               left  = get_Sub_left(left);
-
-                                               tv = value_of(right);
-                                               changed = 1;
-                                               DBG_OPT_ALGSIM0(n, n, FS_OPT_CMP_OP_C);
-                                       }
-#endif
-
                                        if (tv != tarval_bad) {
                                                /* a-c1 == c2  ==>  a == c2+c1,  a-c1 != c2  ==>  a != c2+c1 */
                                                if (is_Sub(left)) {
@@ -4485,10 +4486,12 @@ static ir_node *transform_node_Proj_CopyB(ir_node *proj)
                        DBG_OPT_EXC_REM(proj);
                        proj = new_r_Jmp(get_nodes_block(copyb));
                        break;
-               case pn_CopyB_X_except:
+               case pn_CopyB_X_except: {
+                       ir_graph *irg = get_irn_irg(proj);
                        DBG_OPT_EXC_REM(proj);
-                       proj = get_irg_bad(get_irn_irg(proj));
+                       proj = new_r_Bad(irg, mode_X);
                        break;
+               }
                default:
                        break;
                }
@@ -4536,7 +4539,7 @@ static ir_node *transform_node_Proj_Bound(ir_node *proj)
                        break;
                case pn_Bound_X_except:
                        DBG_OPT_EXC_REM(proj);
-                       proj = get_irg_bad(get_irn_irg(proj));
+                       proj = new_r_Bad(get_irn_irg(proj), mode_X);
                        break;
                case pn_Bound_res:
                        proj = idx;
@@ -4566,14 +4569,57 @@ static ir_node *transform_node_Proj(ir_node *proj)
        return proj;
 }  /* transform_node_Proj */
 
-/**
- * Move Confirms down through Phi nodes.
- */
+static bool is_block_unreachable(const ir_node *block)
+{
+       const ir_graph *irg = get_irn_irg(block);
+       if (!is_irg_state(irg, IR_GRAPH_STATE_BAD_BLOCK))
+               return false;
+       return get_Block_dom_depth(block) < 0;
+}
+
+static ir_node *transform_node_Block(ir_node *block)
+{
+       ir_graph *irg   = get_irn_irg(block);
+       int       arity = get_irn_arity(block);
+       ir_node  *bad   = NULL;
+       int       i;
+
+       if (!is_irg_state(irg, IR_GRAPH_STATE_BAD_BLOCK))
+               return block;
+
+       for (i = 0; i < arity; ++i) {
+               ir_node *pred       = get_Block_cfgpred(block, i);
+               ir_node *pred_block = get_nodes_block(pred);
+               if (!is_Bad(pred) && !is_block_unreachable(pred_block))
+                       continue;
+               if (bad == NULL)
+                       bad = new_r_Bad(irg, mode_X);
+               set_irn_n(block, i, bad);
+       }
+
+       return block;
+}
+
 static ir_node *transform_node_Phi(ir_node *phi)
 {
-       int i, n;
-       ir_mode *mode = get_irn_mode(phi);
+       int       n     = get_irn_arity(phi);
+       ir_mode  *mode  = get_irn_mode(phi);
+       ir_node  *block = get_nodes_block(phi);
+       ir_graph *irg   = get_irn_irg(phi);
+       ir_node  *bad   = NULL;
+       int       i;
 
+       /* Set phi-operands for bad-block inputs to bad */
+       for (i = 0; i < n; ++i) {
+               ir_node *pred = get_Block_cfgpred(block, i);
+               if (is_Bad(pred) || is_block_unreachable(get_nodes_block(pred))) {
+                       if (bad == NULL)
+                               bad = new_r_Bad(irg, mode);
+                       set_irn_n(phi, i, bad);
+               }
+       }
+
+       /* Move Confirms down through Phi nodes. */
        if (mode_is_reference(mode)) {
                n = get_irn_arity(phi);
 
@@ -4802,20 +4848,19 @@ static ir_node *transform_node_Or_Rotl(ir_node *irn_or)
        return n;
 }  /* transform_node_Or_Rotl */
 
-static bool is_cmp_unequal_zero(const ir_node *node)
+static bool is_cmp_unequal(const ir_node *node)
 {
        ir_relation relation = get_Cmp_relation(node);
        ir_node    *left     = get_Cmp_left(node);
        ir_node    *right    = get_Cmp_right(node);
        ir_mode    *mode     = get_irn_mode(left);
 
-       if (!is_Const(right) || !is_Const_null(right))
-               return false;
-       if (mode_is_signed(mode)) {
-               return relation == ir_relation_less_greater;
-       } else {
+       if (relation == ir_relation_less_greater)
+               return true;
+
+       if (!mode_is_signed(mode) && is_Const(right) && is_Const_null(right))
                return relation == ir_relation_greater;
-       }
+       return false;
 }
 
 /**
@@ -4855,18 +4900,21 @@ static ir_node *transform_node_Or(ir_node *n)
                        ir_relation new_relation = a_relation | b_relation;
                        return new_rd_Cmp(dbgi, block, a_left, a_right, new_relation);
                }
-               /* Cmp(a!=0) or Cmp(b!=0) => Cmp(a|b != 0) */
-               if (is_cmp_unequal_zero(a) && is_cmp_unequal_zero(b)
-                               && !mode_is_float(get_irn_mode(a_left))
-                               && !mode_is_float(get_irn_mode(b_left))) {
-                       ir_graph *irg      = get_irn_irg(n);
-                       dbg_info *dbgi     = get_irn_dbg_info(n);
-                       ir_node  *block    = get_nodes_block(n);
-                       ir_mode  *mode     = get_irn_mode(a_left);
-                       ir_node  *n_b_left = get_irn_mode(b_left) != mode ?
-                               new_rd_Conv(dbgi, block, b_left, mode) : b_left;
-                       ir_node  *or   = new_rd_Or(dbgi, block, a_left, n_b_left, mode);
-                       ir_node  *zero = create_zero_const(irg, mode);
+               /* Cmp(a!=b) or Cmp(c!=d) => Cmp((a^b)|(c^d) != 0) */
+               if (is_cmp_unequal(a) && is_cmp_unequal(b)
+                   && !mode_is_float(get_irn_mode(a_left))
+                   && !mode_is_float(get_irn_mode(b_left))
+                   && values_in_mode(get_irn_mode(a_left), get_irn_mode(b_left))) {
+                       ir_graph *irg    = get_irn_irg(n);
+                       dbg_info *dbgi   = get_irn_dbg_info(n);
+                       ir_node  *block  = get_nodes_block(n);
+                       ir_mode  *a_mode = get_irn_mode(a_left);
+                       ir_mode  *b_mode = get_irn_mode(b_left);
+                       ir_node  *xora   = new_rd_Eor(dbgi, block, a_left, a_right, a_mode);
+                       ir_node  *xorb   = new_rd_Eor(dbgi, block, b_left, b_right, b_mode);
+                       ir_node  *conv   = new_rd_Conv(dbgi, block, xorb, a_mode);
+                       ir_node  *or     = new_rd_Or(dbgi, block, xora, conv, a_mode);
+                       ir_node  *zero   = create_zero_const(irg, a_mode);
                        return new_rd_Cmp(dbgi, block, or, zero, ir_relation_less_greater);
                }
        }
@@ -4880,6 +4928,8 @@ static ir_node *transform_node_Or(ir_node *n)
                return n;
 
        n = transform_bitwise_distributive(n, transform_node_Or);
+       if (is_Or(n))
+               n = transform_node_bitop_shift(n);
 
        return n;
 }  /* transform_node_Or */
@@ -4897,9 +4947,11 @@ static ir_node *transform_node_shift(ir_node *n)
 {
        ir_node *left, *right;
        ir_mode *mode;
+       ir_mode *count_mode;
        ir_tarval *tv1, *tv2, *res;
        ir_node *in[2], *irn, *block;
        ir_graph *irg;
+       int       modulo_shf;
 
        left = get_binop_left(n);
 
@@ -4908,7 +4960,7 @@ static ir_node *transform_node_shift(ir_node *n)
                return n;
 
        right = get_binop_right(n);
-       tv1 = value_of(right);
+       tv1   = value_of(right);
        if (tv1 == tarval_bad)
                return n;
 
@@ -4916,37 +4968,55 @@ static ir_node *transform_node_shift(ir_node *n)
        if (tv2 == tarval_bad)
                return n;
 
-       res  = tarval_add(tv1, tv2);
-       mode = get_irn_mode(n);
-       irg  = get_irn_irg(n);
+       count_mode = get_tarval_mode(tv1);
+       if (get_tarval_mode(tv2) != count_mode) {
+               /* TODO: search bigger mode or something and convert... */
+               return n;
+       }
 
-       /* beware: a simple replacement works only, if res < modulo shift */
-       if (!is_Rotl(n)) {
-               int modulo_shf = get_mode_modulo_shift(mode);
-               if (modulo_shf > 0) {
-                       ir_tarval *modulo = new_tarval_from_long(modulo_shf,
-                                                                get_tarval_mode(res));
+       mode       = get_irn_mode(n);
+       modulo_shf = get_mode_modulo_shift(mode);
 
-                       assert(modulo_shf >= (int) get_mode_size_bits(mode));
+       if (modulo_shf > 0) {
+               ir_tarval *modulo_mask = new_tarval_from_long(modulo_shf-1, count_mode);
 
-                       /* shifting too much */
-                       if (!(tarval_cmp(res, modulo) & ir_relation_less)) {
-                               if (is_Shrs(n)) {
-                                       ir_node  *block = get_nodes_block(n);
-                                       dbg_info *dbgi  = get_irn_dbg_info(n);
-                                       ir_mode  *smode  = get_irn_mode(right);
-                                       ir_node  *cnst  = new_r_Const_long(irg, smode, get_mode_size_bits(mode) - 1);
-                                       return new_rd_Shrs(dbgi, block, get_binop_left(left), cnst, mode);
-                               }
+               /* I'm not so sure what happens in one complement... */
+               assert(get_mode_arithmetic(count_mode) == irma_twos_complement);
+               /* modulo shifts should always be a power of 2 (otherwise modulo_mask
+                * above will be invalid) */
+               assert(modulo_shf<=0 || is_po2(modulo_shf));
 
-                               return new_r_Const(irg, get_mode_null(mode));
+               tv1 = tarval_and(tv1, modulo_mask);
+               tv2 = tarval_and(tv2, modulo_mask);
+       }
+       res = tarval_add(tv1, tv2);
+       irg = get_irn_irg(n);
+
+       /* beware: a simple replacement works only, if res < modulo shift */
+       if (is_Rotl(n)) {
+               int        bits   = get_mode_size_bits(mode);
+               ir_tarval *modulo = new_tarval_from_long(bits, count_mode);
+               res = tarval_mod(res, modulo);
+       } else {
+               long       bits      = get_mode_size_bits(mode);
+               ir_tarval *mode_size = new_tarval_from_long(bits, count_mode);
+
+               /* shifting too much */
+               if (!(tarval_cmp(res, mode_size) & ir_relation_less)) {
+                       if (is_Shrs(n)) {
+                               ir_node  *block = get_nodes_block(n);
+                               dbg_info *dbgi  = get_irn_dbg_info(n);
+                               ir_mode  *smode = get_irn_mode(right);
+                               ir_node  *cnst  = new_r_Const_long(irg, smode, get_mode_size_bits(mode) - 1);
+                               return new_rd_Shrs(dbgi, block, get_binop_left(left), cnst, mode);
                        }
+
+                       return new_r_Const(irg, get_mode_null(mode));
                }
-       } else {
-               res = tarval_mod(res, new_tarval_from_long(get_mode_size_bits(mode), get_tarval_mode(res)));
        }
 
        /* ok, we can replace it */
+       assert(modulo_shf >= (int) get_mode_size_bits(mode));
        block = get_nodes_block(n);
 
        in[0] = get_binop_left(left);
@@ -4957,91 +5027,6 @@ static ir_node *transform_node_shift(ir_node *n)
        DBG_OPT_ALGSIM0(n, irn, FS_OPT_REASSOC_SHIFT);
 
        return transform_node(irn);
-}  /* transform_node_shift */
-
-/**
- * normalisation: (x & c1) >> c2   to   (x >> c2) & (c1 >> c2)
- *  (we can use:
- *    - and, or, xor          instead of &
- *    - Shl, Shr, Shrs, rotl  instead of >>
- *    (with a special case for Or/Xor + Shrs)
- */
-static ir_node *transform_node_bitop_shift(ir_node *n)
-{
-       ir_node   *left;
-       ir_node   *right = get_binop_right(n);
-       ir_mode   *mode  = get_irn_mode(n);
-       ir_node   *bitop_left;
-       ir_node   *bitop_right;
-       ir_op     *op_left;
-       ir_node   *block;
-       dbg_info  *dbgi;
-       ir_graph  *irg;
-       ir_node   *new_shift;
-       ir_node   *new_bitop;
-       ir_node   *new_const;
-       ir_tarval *tv1;
-       ir_tarval *tv2;
-       ir_tarval *tv_shift;
-
-       assert(is_Shrs(n) || is_Shr(n) || is_Shl(n) || is_Rotl(n));
-
-       if (!is_Const(right))
-               return n;
-
-       left    = get_binop_left(n);
-       op_left = get_irn_op(left);
-       if (op_left != op_And && op_left != op_Or && op_left != op_Eor)
-               return n;
-
-       /* doing it with Shrs is not legal if the Or/Eor affects the topmost bit */
-       if (is_Shrs(n) && (op_left == op_Or || op_left == op_Eor)) {
-               /* TODO: test if sign bit is affectes */
-               return n;
-       }
-
-       bitop_right = get_binop_right(left);
-       if (!is_Const(bitop_right))
-               return n;
-
-       bitop_left = get_binop_left(left);
-
-       block = get_nodes_block(n);
-       dbgi  = get_irn_dbg_info(n);
-       tv1   = get_Const_tarval(bitop_right);
-       tv2   = get_Const_tarval(right);
-
-       assert(get_tarval_mode(tv1) == mode);
-
-       if (is_Shl(n)) {
-               new_shift = new_rd_Shl(dbgi, block, bitop_left, right, mode);
-               tv_shift  = tarval_shl(tv1, tv2);
-       } else if (is_Shr(n)) {
-               new_shift = new_rd_Shr(dbgi, block, bitop_left, right, mode);
-               tv_shift  = tarval_shr(tv1, tv2);
-       } else if (is_Shrs(n)) {
-               new_shift = new_rd_Shrs(dbgi, block, bitop_left, right, mode);
-               tv_shift  = tarval_shrs(tv1, tv2);
-       } else {
-               assert(is_Rotl(n));
-               new_shift = new_rd_Rotl(dbgi, block, bitop_left, right, mode);
-               tv_shift  = tarval_rotl(tv1, tv2);
-       }
-
-       assert(get_tarval_mode(tv_shift) == mode);
-       irg       = get_irn_irg(n);
-       new_const = new_r_Const(irg, tv_shift);
-
-       if (op_left == op_And) {
-               new_bitop = new_rd_And(dbgi, block, new_shift, new_const, mode);
-       } else if (op_left == op_Or) {
-               new_bitop = new_rd_Or(dbgi, block, new_shift, new_const, mode);
-       } else {
-               assert(op_left == op_Eor);
-               new_bitop = new_rd_Eor(dbgi, block, new_shift, new_const, mode);
-       }
-
-       return new_bitop;
 }
 
 /**
@@ -5162,7 +5147,7 @@ typedef ir_node*(*new_shift_func)(dbg_info *dbgi, ir_node *block,
  * then we can use that to minimize the value of Add(x, const) or
  * Sub(Const, x). In particular this often avoids 1 instruction in some
  * backends for the Shift(x, Sub(Const, y)) case because it can be replaced
- * by Shift(x, Minus(y)) which doesnt't need an explicit Const constructed.
+ * by Shift(x, Minus(y)) which does not need an explicit Const constructed.
  */
 static ir_node *transform_node_shift_modulo(ir_node *n,
                                             new_shift_func new_shift)
@@ -5250,7 +5235,7 @@ static ir_node *transform_node_Shr(ir_node *n)
        if (is_Shr(n))
                n = transform_node_shl_shr(n);
        if (is_Shr(n))
-               n = transform_node_bitop_shift(n);
+               n = transform_node_shift_bitop(n);
 
        return n;
 }  /* transform_node_Shr */
@@ -5265,13 +5250,23 @@ static ir_node *transform_node_Shrs(ir_node *n)
        ir_node *b    = get_Shrs_right(n);
        ir_mode *mode = get_irn_mode(n);
 
+       if (is_oversize_shift(n)) {
+               ir_node  *block = get_nodes_block(n);
+               dbg_info *dbgi  = get_irn_dbg_info(n);
+               ir_mode  *cmode = get_irn_mode(b);
+               long      val   = get_mode_size_bits(cmode)-1;
+               ir_graph *irg   = get_irn_irg(n);
+               ir_node  *cnst  = new_r_Const_long(irg, cmode, val);
+               return new_rd_Shrs(dbgi, block, a, cnst, mode);
+       }
+
        HANDLE_BINOP_PHI((eval_func) tarval_shrs, a, b, c, mode);
        n = transform_node_shift(n);
 
        if (is_Shrs(n))
                n = transform_node_shift_modulo(n, new_rd_Shrs);
        if (is_Shrs(n))
-               n = transform_node_bitop_shift(n);
+               n = transform_node_shift_bitop(n);
 
        return n;
 }  /* transform_node_Shrs */
@@ -5294,7 +5289,7 @@ static ir_node *transform_node_Shl(ir_node *n)
        if (is_Shl(n))
                n = transform_node_shl_shr(n);
        if (is_Shl(n))
-               n = transform_node_bitop_shift(n);
+               n = transform_node_shift_bitop(n);
 
        return n;
 }  /* transform_node_Shl */
@@ -5313,7 +5308,7 @@ static ir_node *transform_node_Rotl(ir_node *n)
        n = transform_node_shift(n);
 
        if (is_Rotl(n))
-               n = transform_node_bitop_shift(n);
+               n = transform_node_shift_bitop(n);
 
        return n;
 }  /* transform_node_Rotl */
@@ -5385,17 +5380,14 @@ static ir_node *transform_node_End(ir_node *n)
 
        for (i = j = 0; i < n_keepalives; ++i) {
                ir_node *ka = get_End_keepalive(n, i);
-               if (is_Block(ka)) {
-                       if (! is_Block_dead(ka)) {
-                               in[j++] = ka;
-                       }
-                       continue;
-               } else if (is_irn_pinned_in_irg(ka) && is_Block_dead(get_nodes_block(ka))) {
+               ir_node *block;
+               /* no need to keep Bad */
+               if (is_Bad(ka))
                        continue;
-               } else if (is_Bad(ka)) {
-                       /* no need to keep Bad */
+               /* do not keep unreachable code */
+               block = is_Block(ka) ? ka : get_nodes_block(ka);
+               if (is_block_unreachable(block))
                        continue;
-               }
                in[j++] = ka;
        }
        if (j != n_keepalives)
@@ -5422,16 +5414,115 @@ int ir_is_negated_value(const ir_node *a, const ir_node *b)
        return false;
 }
 
+static const ir_node *skip_upconv(const ir_node *node)
+{
+       while (is_Conv(node)) {
+               ir_mode       *mode    = get_irn_mode(node);
+               const ir_node *op      = get_Conv_op(node);
+               ir_mode       *op_mode = get_irn_mode(op);
+               if (!smaller_mode(op_mode, mode))
+                       break;
+               node = op;
+       }
+       return node;
+}
+
+int ir_mux_is_abs(const ir_node *sel, const ir_node *mux_true,
+                  const ir_node *mux_false)
+{
+       ir_node    *cmp_left;
+       ir_node    *cmp_right;
+       ir_mode    *mode;
+       ir_relation relation;
+
+       if (!is_Cmp(sel))
+               return 0;
+
+       /**
+        * Note further that these optimization work even for floating point
+        * with NaN's because -NaN == NaN.
+        * However, if +0 and -0 is handled differently, we cannot use the Abs/-Abs
+        * transformations.
+        */
+       mode = get_irn_mode(mux_true);
+       if (mode_honor_signed_zeros(mode))
+               return 0;
+
+       /* must be <, <=, >=, > */
+       relation = get_Cmp_relation(sel);
+       if ((relation & ir_relation_less_greater) == 0)
+               return 0;
+
+       if (!ir_is_negated_value(mux_true, mux_false))
+               return 0;
+
+       mux_true  = skip_upconv(mux_true);
+       mux_false = skip_upconv(mux_false);
+
+       /* must be x cmp 0 */
+       cmp_right = get_Cmp_right(sel);
+       if (!is_Const(cmp_right) || !is_Const_null(cmp_right))
+               return 0;
+
+       cmp_left = get_Cmp_left(sel);
+       if (cmp_left == mux_false) {
+               if (relation & ir_relation_less) {
+                       return 1;
+               } else {
+                       assert(relation & ir_relation_greater);
+                       return -1;
+               }
+       } else if (cmp_left == mux_true) {
+               if (relation & ir_relation_less) {
+                       return -1;
+               } else {
+                       assert(relation & ir_relation_greater);
+                       return 1;
+               }
+       }
+
+       return 0;
+}
+
+ir_node *ir_get_abs_op(const ir_node *sel, ir_node *mux_true,
+                       ir_node *mux_false)
+{
+       ir_node *cmp_left = get_Cmp_left(sel);
+       return cmp_left == skip_upconv(mux_false) ? mux_false : mux_true;
+}
+
 /**
  * Optimize a Mux into some simpler cases.
  */
 static ir_node *transform_node_Mux(ir_node *n)
 {
-       ir_node *oldn = n, *sel = get_Mux_sel(n);
-       ir_mode *mode = get_irn_mode(n);
-       ir_node  *t   = get_Mux_true(n);
-       ir_node  *f   = get_Mux_false(n);
-       ir_graph *irg = get_irn_irg(n);
+       ir_node  *oldn = n;
+       ir_node  *sel  = get_Mux_sel(n);
+       ir_mode  *mode = get_irn_mode(n);
+       ir_node  *t    = get_Mux_true(n);
+       ir_node  *f    = get_Mux_false(n);
+       ir_graph *irg  = get_irn_irg(n);
+
+       /* implement integer abs: abs(x) = x^(x >>s 31) - (x >>s 31) */
+       if (get_mode_arithmetic(mode) == irma_twos_complement) {
+               int abs = ir_mux_is_abs(sel, t, f);
+               if (abs != 0) {
+                       dbg_info *dbgi       = get_irn_dbg_info(n);
+                       ir_node  *block      = get_nodes_block(n);
+                       ir_node  *op         = ir_get_abs_op(sel, t, f);
+                       int       bits       = get_mode_size_bits(mode);
+                       ir_node  *shiftconst = new_r_Const_long(irg, mode_Iu, bits-1);
+                       ir_node  *sext       = new_rd_Shrs(dbgi, block, op, shiftconst, mode);
+                       ir_node  *xorn       = new_rd_Eor(dbgi, block, op, sext, mode);
+                       ir_node  *res;
+                       if (abs > 0) {
+                               res = new_rd_Sub(dbgi, block, xorn, sext, mode);
+                       } else {
+                               res = new_rd_Sub(dbgi, block, sext, xorn, mode);
+                       }
+                       return res;
+               }
+       }
 
        if (is_irg_state(irg, IR_GRAPH_STATE_KEEP_MUX))
                return n;
@@ -5656,6 +5747,24 @@ static ir_node *transform_node_Sync(ir_node *n)
                int      pred_arity;
                int      j;
 
+               /* Remove Bad predecessors */
+               if (is_Bad(pred)) {
+                       del_Sync_n(n, i);
+                       --arity;
+                       continue;
+               }
+
+               /* Remove duplicate predecessors */
+               for (j = 0; j < i; ++j) {
+                       if (get_Sync_pred(n, j) == pred) {
+                               del_Sync_n(n, i);
+                               --arity;
+                               break;
+                       }
+               }
+               if (j < i)
+                       continue;
+
                if (!is_Sync(pred)) {
                        ++i;
                        continue;
@@ -5680,11 +5789,78 @@ static ir_node *transform_node_Sync(ir_node *n)
                }
        }
 
+       if (arity == 0) {
+               ir_graph *irg = get_irn_irg(n);
+               return new_r_Bad(irg, mode_M);
+       }
+       if (arity == 1) {
+               return get_Sync_pred(n, 0);
+       }
+
        /* rehash the sync node */
        add_identities(n);
+       return n;
+}
+
+static ir_node *transform_node_Load(ir_node *n)
+{
+       /* if our memory predecessor is a load from the same address, then reuse the
+        * previous result */
+       ir_node *mem = get_Load_mem(n);
+       ir_node *mem_pred;
+
+       if (!is_Proj(mem))
+               return n;
+       /* don't touch volatile loads */
+       if (get_Load_volatility(n) == volatility_is_volatile)
+               return n;
+       mem_pred = get_Proj_pred(mem);
+       if (is_Load(mem_pred)) {
+               ir_node *pred_load = mem_pred;
+
+               /* conservatively compare the 2 loads. TODO: This could be less strict
+                * with fixup code in some situations (like smaller/bigger modes) */
+               if (get_Load_ptr(pred_load) != get_Load_ptr(n))
+                       return n;
+               if (get_Load_mode(pred_load) != get_Load_mode(n))
+                       return n;
+               /* all combinations of aligned/unaligned pred/n should be fine so we do
+                * not compare the unaligned attribute */
+               {
+                       ir_node  *block = get_nodes_block(n);
+                       ir_node  *jmp   = new_r_Jmp(block);
+                       ir_graph *irg   = get_irn_irg(n);
+                       ir_node  *bad   = new_r_Bad(irg, mode_X);
+                       ir_mode  *mode  = get_Load_mode(n);
+                       ir_node  *res   = new_r_Proj(pred_load, mode, pn_Load_res);
+                       ir_node  *in[pn_Load_max+1] = { mem, res, jmp, bad };
+                       ir_node  *tuple = new_r_Tuple(block, ARRAY_SIZE(in), in);
+                       return tuple;
+               }
+       } else if (is_Store(mem_pred)) {
+               ir_node *pred_store = mem_pred;
+               ir_node *value      = get_Store_value(pred_store);
+
+               if (get_Store_ptr(pred_store) != get_Load_ptr(n))
+                       return n;
+               if (get_irn_mode(value) != get_Load_mode(n))
+                       return n;
+               /* all combinations of aligned/unaligned pred/n should be fine so we do
+                * not compare the unaligned attribute */
+               {
+                       ir_node  *block = get_nodes_block(n);
+                       ir_node  *jmp   = new_r_Jmp(block);
+                       ir_graph *irg   = get_irn_irg(n);
+                       ir_node  *bad   = new_r_Bad(irg, mode_X);
+                       ir_node  *res   = value;
+                       ir_node  *in[pn_Load_max+1] = { mem, res, jmp, bad };
+                       ir_node  *tuple = new_r_Tuple(block, ARRAY_SIZE(in), in);
+                       return tuple;
+               }
+       }
 
        return n;
-}  /* transform_node_Sync */
+}
 
 /**
  * optimize a trampoline Call into a direct Call
@@ -5808,6 +5984,7 @@ static ir_op_ops *firm_set_default_transform_node(ir_opcode code, ir_op_ops *ops
        switch (code) {
        CASE(Add);
        CASE(And);
+       CASE(Block);
        CASE(Call);
        CASE(Cmp);
        CASE(Conv);
@@ -5829,13 +6006,13 @@ static ir_op_ops *firm_set_default_transform_node(ir_opcode code, ir_op_ops *ops
        CASE(Sync);
        CASE_PROJ(Bound);
        CASE_PROJ(CopyB);
-       CASE_PROJ(Load);
        CASE_PROJ(Store);
        CASE_PROJ_EX(Cond);
        CASE_PROJ_EX(Div);
+       CASE_PROJ_EX(Load);
        CASE_PROJ_EX(Mod);
        default:
-         /* leave NULL */;
+               break;
        }
 
        return ops;
@@ -6139,10 +6316,23 @@ int identities_cmp(const void *elt, const void *key)
                /* for pinned nodes, the block inputs must be equal */
                if (get_irn_n(a, -1) != get_irn_n(b, -1))
                        return 1;
-       } else if (! get_opt_global_cse()) {
-               /* for block-local CSE both nodes must be in the same Block */
-               if (get_nodes_block(a) != get_nodes_block(b))
-                       return 1;
+       } else {
+               ir_node *block_a = get_nodes_block(a);
+               ir_node *block_b = get_nodes_block(b);
+               if (! get_opt_global_cse()) {
+                       /* for block-local CSE both nodes must be in the same Block */
+                       if (block_a != block_b)
+                               return 1;
+               } else {
+                       /* The optimistic approach would be to do nothing here.
+                        * However doing GCSE optimistically produces a lot of partially dead code which appears
+                        * to be worse in practice than the missed opportunities.
+                        * So we use a very conservative variant here and only CSE if 1 value dominates the
+                        * other. */
+                       if (!block_dominates(block_a, block_b)
+                           && !block_dominates(block_b, block_a))
+                           return 1;
+               }
        }
 
        /* compare a->in[0..ins] with b->in[0..ins] */
@@ -6284,100 +6474,6 @@ void visit_all_identities(ir_graph *irg, irg_walk_func visit, void *env)
        current_ir_graph = rem;
 }  /* visit_all_identities */
 
-/**
- * Garbage in, garbage out. If a node has a dead input, i.e., the
- * Bad node is input to the node, return the Bad node.
- */
-static ir_node *gigo(ir_node *node)
-{
-       int i, irn_arity;
-       ir_op *op = get_irn_op(node);
-
-       /* remove garbage blocks by looking at control flow that leaves the block
-          and replacing the control flow by Bad. */
-       if (get_irn_mode(node) == mode_X) {
-               ir_node  *block = get_nodes_block(skip_Proj(node));
-               ir_graph *irg   = get_irn_irg(block);
-
-               /* Don't optimize nodes in immature blocks. */
-               if (!get_Block_matured(block))
-                       return node;
-               /* Don't optimize End, may have Bads. */
-               if (op == op_End) return node;
-
-               if (is_Block(block)) {
-                       if (is_Block_dead(block)) {
-                               /* control flow from dead block is dead */
-                               return get_irg_bad(irg);
-                       }
-
-                       for (i = get_irn_arity(block) - 1; i >= 0; --i) {
-                               if (!is_Bad(get_irn_n(block, i)))
-                                       break;
-                       }
-                       if (i < 0) {
-                               ir_graph *irg = get_irn_irg(block);
-                               /* the start block is never dead */
-                               if (block != get_irg_start_block(irg)
-                                       && block != get_irg_end_block(irg)) {
-                                       /*
-                                        * Do NOT kill control flow without setting
-                                        * the block to dead of bad things can happen:
-                                        * We get a Block that is not reachable be irg_block_walk()
-                                        * but can be found by irg_walk()!
-                                        */
-                                       set_Block_dead(block);
-                                       return get_irg_bad(irg);
-                               }
-                       }
-               }
-       }
-
-       /* Blocks, Phis and Tuples may have dead inputs, e.g., if one of the
-          blocks predecessors is dead. */
-       if (op != op_Block && op != op_Phi && op != op_Tuple && op != op_Anchor) {
-               ir_graph *irg = get_irn_irg(node);
-               irn_arity = get_irn_arity(node);
-
-               /*
-                * Beware: we can only read the block of a non-floating node.
-                */
-               if (is_irn_pinned_in_irg(node) &&
-                       is_Block_dead(get_nodes_block(skip_Proj(node))))
-                       return get_irg_bad(irg);
-
-               for (i = 0; i < irn_arity; i++) {
-                       ir_node *pred = get_irn_n(node, i);
-
-                       if (is_Bad(pred))
-                               return get_irg_bad(irg);
-#if 0
-                       /* Propagating Unknowns here seems to be a bad idea, because
-                          sometimes we need a node as a input and did not want that
-                          it kills its user.
-                          However, it might be useful to move this into a later phase
-                          (if you think that optimizing such code is useful). */
-                       if (is_Unknown(pred) && mode_is_data(get_irn_mode(node)))
-                               return new_r_Unknown(irg, get_irn_mode(node));
-#endif
-               }
-       }
-#if 0
-       /* With this code we violate the agreement that local_optimize
-          only leaves Bads in Block, Phi and Tuple nodes. */
-       /* If Block has only Bads as predecessors it's garbage. */
-       /* If Phi has only Bads as predecessors it's garbage. */
-       if ((op == op_Block && get_Block_matured(node)) || op == op_Phi)  {
-               irn_arity = get_irn_arity(node);
-               for (i = 0; i < irn_arity; i++) {
-                       if (!is_Bad(get_irn_n(node, i))) break;
-               }
-               if (i == irn_arity) node = get_irg_bad(irg);
-       }
-#endif
-       return node;
-}  /* gigo */
-
 /**
  * These optimizations deallocate nodes from the obstack.
  * It can only be called if it is guaranteed that no other nodes
@@ -6395,17 +6491,6 @@ ir_node *optimize_node(ir_node *n)
        /* Always optimize Phi nodes: part of the construction. */
        if ((!get_opt_optimize()) && (iro != iro_Phi)) return n;
 
-       /* Remove nodes with dead (Bad) input.
-          Run always for transformation induced Bads. */
-       n = gigo(n);
-       if (n != oldn) {
-               edges_node_deleted(oldn);
-
-               /* We found an existing, better node, so we can deallocate the old node. */
-               irg_kill_node(irg, oldn);
-               return n;
-       }
-
        /* constant expression evaluation / constant folding */
        if (get_opt_constant_folding()) {
                /* neither constants nor Tuple values can be evaluated */
@@ -6504,12 +6589,6 @@ ir_node *optimize_in_place_2(ir_node *n)
        if (iro == iro_Deleted)
                return n;
 
-       /* Remove nodes with dead (Bad) input.
-          Run always for transformation induced Bads.  */
-       n = gigo(n);
-       if (is_Bad(n))
-               return n;
-
        /* constant expression evaluation / constant folding */
        if (get_opt_constant_folding()) {
                /* neither constants nor Tuple values can be evaluated */
@@ -6582,8 +6661,6 @@ ir_node *optimize_in_place(ir_node *n)
 
        if (get_opt_global_cse())
                set_irg_pinned(irg, op_pin_state_floats);
-       if (get_irg_outs_state(irg) == outs_consistent)
-               set_irg_outs_inconsistent(irg);
 
        /* FIXME: Maybe we could also test whether optimizing the node can
           change the control graph. */