Complement r22830.

[libfirm] / ir / be / belower.c

diff --git a/ir/be/belower.c b/ir/be/belower.c
index 53655e7..ab2559f 100644 (file)
--- a/ir/be/belower.c
+++ b/ir/be/belower.c
@@ -30,7 +30,6 @@
 
 #include "ircons.h"
 #include "debug.h"
-#include "irhooks.h"
 #include "xmalloc.h"
 #include "irnodeset.h"
 #include "irnodemap.h"
@@ -291,8 +290,8 @@ static void lower_perm_node(ir_node *irn, lower_env_t *env)
        const arch_register_class_t *const reg_class   = arch_get_irn_register(get_irn_n(irn, 0))->reg_class;
        ir_graph                    *const irg         = get_irn_irg(irn);
        ir_node                     *const block       = get_nodes_block(irn);
-       int                          const n           = get_irn_arity(irn);
-       reg_pair_t                  *const pairs       = alloca(n * sizeof(pairs[0]));
+       int                          const arity       = get_irn_arity(irn);
+       reg_pair_t                  *const pairs       = alloca(arity * sizeof(pairs[0]));
        int                                keep_perm   = 0;
        int                                do_copy     = env->do_copy;
        /* Get the schedule predecessor node to the perm.
@@ -300,21 +299,33 @@ static void lower_perm_node(ir_node *irn, lower_env_t *env)
         * nodes after this node, everything should be ok. */
        ir_node                     *      sched_point = sched_prev(irn);
        const ir_edge_t             *      edge;
+       const ir_edge_t             *      next;
+       int                                n;
        int                                i;
 
        DBG((dbg, LEVEL_1, "perm: %+F, sched point is %+F\n", irn, sched_point));
        assert(sched_point && "Perm is not scheduled or has no predecessor");
 
-       assert(n == get_irn_n_edges(irn) && "perm's in and out numbers different");
+       assert(arity == get_irn_n_edges(irn) && "perm's in and out numbers different");
 
        /* build the list of register pairs (in, out) */
-       i = 0;
-       foreach_out_edge(irn, edge) {
-               reg_pair_t *const pair = &pairs[i++];
-               ir_node    *const out  = get_edge_src_irn(edge);
-               long        const pn   = get_Proj_proj(out);
-               ir_node    *const in   = get_irn_n(irn, pn);
+       n = 0;
+       foreach_out_edge_safe(irn, edge, next) {
+               ir_node               *const out     = get_edge_src_irn(edge);
+               long                   const pn      = get_Proj_proj(out);
+               ir_node               *const in      = get_irn_n(irn, pn);
+               arch_register_t const *const in_reg  = arch_get_irn_register(in);
+               arch_register_t const *const out_reg = arch_get_irn_register(out);
+               reg_pair_t            *      pair;
+
+               if (in_reg == out_reg) {
+                       DBG((dbg, LEVEL_1, "%+F removing equal perm register pair (%+F, %+F, %s)\n",
+                                               irn, in, out, out_reg->name));
+                       exchange(out, in);
+                       continue;
+               }
 
+               pair           = &pairs[n++];
                pair->in_node  = in;
                pair->in_reg   = arch_get_irn_register(in);
                pair->out_node = out;
@@ -322,22 +333,7 @@ static void lower_perm_node(ir_node *irn, lower_env_t *env)
                pair->checked  = 0;
        }
 
-       /* Mark all equal pairs as checked, and exchange the OUT proj with the IN
-        * node. */
-       for (i = 0; i < n; i++) {
-               reg_pair_t *const pair = &pairs[i];
-
-               if (pair->in_reg->index != pair->out_reg->index)
-                       continue;
-
-               DBG((dbg, LEVEL_1, "%+F removing equal perm register pair (%+F, %+F, %s)\n",
-                                       irn, pair->in_node, pair->out_node, pair->out_reg->name));
-
-               /* reroute the edges from the proj to the argument */
-               exchange(pair->out_node, pair->in_node);
-
-               pair->checked = 1;
-       }
+       DBG((dbg, LEVEL_1, "%+F has %d unresolved constraints\n", irn, n));
 
        /* Set do_copy to 0 if it's on but we have no free register */
        /* TODO check for free register */
@@ -360,7 +356,7 @@ static void lower_perm_node(ir_node *irn, lower_env_t *env)
                }
                DB((dbg, LEVEL_1, "\n"));
 
-               if (n == 2 && cycle.type == PERM_CYCLE) {
+               if (cycle.type == PERM_CYCLE && arity == 2) {
                        /* We don't need to do anything if we have a Perm with two elements
                         * which represents a cycle, because those nodes already represent
                         * exchange nodes */