+
+static INLINE int values_interfere_dom(const ir_node *a, const ir_node *b)
+{
+ const ir_node *b1 = get_nodes_block(a);
+ const ir_node *b2 = get_nodes_block(b);
+ int lo_a, lo_b;
+
+ assert(block_dominates(b1, b2));
+
+ /*
+ * if the two blocks are not equal, a and b can only interfere if a is
+ * live in at b2.
+ */
+ if(b1 != b2 && !is_live_in(b2, a))
+ return 0;
+
+ lo_a = is_live_end(b2, a);
+ lo_b = is_live_end(b2, b);
+
+ /*
+ * If the two blocks are the same and one value is live out and the
+ * definition of the other is after the definition ov the live out
+ * value, they interfere.
+ */
+ if(b1 == b2) {
+ int pos_a = sched_get_time_step(a);
+ int pos_b = sched_get_time_step(b);
+
+ if((pos_a < pos_b && lo_a) || (pos_b < pos_a && lo_b))
+ return 1;
+ }
+
+ /*
+ * Now it is left to check, if the sequence from the last use of 'b'
+ * (or the end of the block b2, if b is live out)
+ * to the def of 'b' contains a use and NOT the def of 'a'. Then they
+ * also interfere
+ */
+ {
+ const ir_node *irn;
+
+ /* Initialize the liveness. */
+ int a_live = lo_a;
+ int b_live = lo_b;
+
+ /* Go from the end of block b2 and try to detect the liveness. */
+ sched_foreach_reverse(b2, irn) {
+ int i, n;
+
+ /*
+ * If the definition of 'a' was found 'a' and 'b' interfere, if
+ * 'b' is live here.
+ */
+ if(irn == a)
+ return b_live;
+
+ /* Same goes for 'b'. */
+ if(irn == b)
+ return a_live;
+
+ /* If 'a' is not yet live, search for a use. */
+ if(!a_live) {
+ for(i = 0, n = get_irn_arity(irn); i < n; ++i)
+ if(get_irn_n(irn, i) == a) {
+ a_live = 1;
+ break;
+ }
+ }
+
+ /* Same for 'b' */
+ if(!b_live) {
+ for(i = 0, n = get_irn_arity(irn); i < n; ++i)
+ if(get_irn_n(irn, i) == b) {
+ b_live = 1;
+ break;
+ }
+ }
+
+ }
+ }
+
+ assert(0 && "You may never reach this place");
+
+ /* This is never reached */
+ return 0;
+}
+
+int values_interfere(const ir_node *a, const ir_node *b)
+{
+ const ir_node *b1 = get_nodes_block(a);
+ const ir_node *b2 = get_nodes_block(b);
+
+ if(block_dominates(b1, b2))
+ return values_interfere_dom(a, b);
+ else if(block_dominates(b2, b1))
+ return values_interfere_dom(b, a);
+ else
+ return 0;
+}