* @author Sebastian Hack
* @date 22.11.2004
*/
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
#include "pset.h"
#include "impl.h"
#include "irnode.h"
#include "irmode.h"
-#include "besched.h"
+#include "irdom.h"
-#include "bera_t.h"
+#include "besched_t.h"
+#include "belive_t.h"
-FIRM_IMPL1(is_allocatable_irn, int, const ir_node *)
+int value_dominates(const ir_node *a, const ir_node *b)
+{
+ int res = 0;
+ const ir_node *ba = get_nodes_block(a);
+ const ir_node *bb = get_nodes_block(a);
+
+ /*
+ * a and b are not in the same block,
+ * so dominance is determined by the dominance of the blocks.
+ */
+ if(ba != bb)
+ res = block_dominates(ba, bb);
-size_t ra_irn_data_offset = 0;
-size_t ra_irg_data_offset = 0;
+ /*
+ * Dominance is determined by the time steps of the schedule.
+ */
+ else {
+ sched_timestep_t as = sched_get_time_step(a);
+ sched_timestep_t bs = sched_get_time_step(b);
+ res = as <= bs;
+ }
+
+ return res;
+}
-void be_ra_init(void)
+/**
+ * Check, if two values interfere.
+ * @param a The first value.
+ * @param b The second value.
+ * @return 1, if a and b interfere, 0 if not.
+ */
+int values_interfere(const ir_node *a, const ir_node *b)
{
- ra_irn_data_offset = register_additional_node_data(sizeof(ra_info_t));
- ra_irg_data_offset = register_additional_graph_data(sizeof(void *));
+ int a2b = value_dominates(a, b);
+ int b2a = value_dominates(b, a);
+
+ /*
+ * Adjust a and b so, that a dominates b if
+ * a dominates b or vice versa.
+ */
+ if(b2a) {
+ const ir_node *t = a;
+ a = b;
+ b = t;
+ }
+
+ /*
+ * If either a dmoninates b or vice versa
+ * check if there is usage which is dominated by b.
+ *
+ * remind, that if a and b are in a dom relation, a always dominates b
+ * here due to the if above.
+ */
+ if(a2b + b2a) {
+ const ir_edge_t *edge;
+
+ /* Look at all usages of a */
+ foreach_out_edge(a, edge) {
+ const ir_node *user = edge->src;
+
+ /*
+ * If the user is a phi we must check the last instruction in the
+ * corresponding phi predecessor block since the phi is not a
+ * proper user.
+ */
+ if(is_Phi(user)) {
+ ir_node *phi_block = get_nodes_block(user);
+ user = sched_last(get_Block_cfgpred_block(phi_block, edge->pos));
+ }
+
+ /* If b dominates a user of a, we can safely return 1 here. */
+ if(value_dominates(b, user))
+ return 1;
+ }
+
+ }
+
+ return 0;
}