Added a computation for spill-slot (offset) assignment.

[libfirm] / ir / be / belower.c

diff --git a/ir/be/belower.c b/ir/be/belower.c
index 1aae93a..23415d1 100644 (file)
--- a/ir/be/belower.c
+++ b/ir/be/belower.c
@@ -18,7 +18,7 @@
 #include "besched.h"
 
 #include "irgmod.h"
-#include "iredges.h"
+#include "iredges_t.h"
 #include "irgwalk.h"
 
 #undef is_Perm
@@ -49,6 +49,7 @@ typedef enum _perm_type_t {
        PERM_COPY
 } perm_type_t;
 
+/* structure to represent cycles or chains in a perm */
 typedef struct _perm_cycle_t {
        const arch_register_t **elems;       /**< the registers in the cycle */
        int                     n_elems;     /**< number of elements in the cycle */
@@ -66,6 +67,7 @@ static int compare_reg_pair(const void *a, const void *b) {
                return -1;
 }
 
+/* returns the number register pairs marked as checked */
 static int get_n_checked_pairs(reg_pair_t *pairs, int n) {
        int i, n_checked = 0;
 
@@ -280,11 +282,10 @@ static void lower_perm_node(ir_node *irn, void *walk_env) {
                                set_Proj_proj(pairs[i].out_node, get_Proj_proj(pairs[i].in_node));
                        }
 
-
                        /* remove the proj from the schedule */
                        sched_remove(pairs[i].out_node);
 
-                       /* exchange the proj with the argument */
+                       /* reroute the edges from the proj to the argument */
                        edges_reroute(pairs[i].out_node, pairs[i].in_node, env->chord_env->irg);
 
                        pairs[i].checked = 1;
@@ -313,7 +314,7 @@ static void lower_perm_node(ir_node *irn, void *walk_env) {
                        continue;
                }
 
-//todo: - iff PERM_CYCLE && do_copy -> determine free temp reg and insert copy to/from it before/after
+//TODO: - iff PERM_CYCLE && do_copy -> determine free temp reg and insert copy to/from it before/after
 //        the copy cascade (this reduces the cycle into a chain)
 
                /* build copy/swap nodes from back to front */