Moved to new lpp library

[libfirm] / ir / be / bera.c

diff --git a/ir/be/bera.c b/ir/be/bera.c
index 7bddee0..ed07567 100644 (file)
--- a/ir/be/bera.c
+++ b/ir/be/bera.c
@@ -3,23 +3,96 @@
  * @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;
 }