X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fbe%2Fbera.c;h=024452ab7dc4cf69a2f971a5b593f7541710c026;hb=17e47394fa72025d14172a2acef2d258a067aa42;hp=4bcc69cba8b52d98c9fc4e8ddd1604f74ec19afb;hpb=5663da1d73944b6aae2bf6d38ef58e188ad76e1c;p=libfirm

diff --git a/ir/be/bera.c b/ir/be/bera.c
index 4bcc69cba..024452ab7 100644
--- a/ir/be/bera.c
+++ b/ir/be/bera.c
@@ -3,6 +3,9 @@
  * @author Sebastian Hack
  * @date 22.11.2004
  */
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 
 #include "pset.h"
 #include "impl.h"
@@ -11,116 +14,89 @@
 #include "irmode.h"
 #include "irdom.h"
 
-#include "bera_t.h"
+#include "beutil.h"
 #include "besched_t.h"
 #include "belive_t.h"
 
-FIRM_IMPL1(is_allocatable_irn, int, const ir_node *)
-
-size_t ra_irn_data_offset = 0;
-size_t ra_irg_data_offset = 0;
-
-void be_ra_init(void)
+int value_dominates(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 *));
-}
-
-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 res = 0;
+	const ir_node *ba = get_block(a);
+	const ir_node *bb = get_block(b);
+
+  /*
+   * 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);
+
+  /*
+   * 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;
 }
 
+/**
+ * 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)
 {
-	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;
+  int a2b = value_dominates(a, b);
+  int b2a = value_dominates(b, a);
+
+  /* If there is no dominance relation, they do not interfere. */
+  if((a2b | b2a) > 0) {
+    const ir_edge_t *edge;
+    ir_node *bb;
+
+    /*
+     * 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;
+    }
+
+		bb = get_nodes_block(b);
+
+    /*
+     * If a is live end in b's block it is
+     * live at b's definition (a dominates b)
+     */
+    if(is_live_end(bb, a))
+      return 1;
+
+    /*
+     * Look at all usages of a.
+     * If there's one usage of a in the block of b, then
+     * we check, if this use is dominated by b, if that's true
+     * a and b interfere. Note that b must strictly dominate the user,
+		 * since if b is the last user of in the block, b and a do not
+		 * interfere.
+     * Uses of a not in b's block can be disobeyed, because the
+     * check for a being live at the end of b's block is already
+     * performed.
+     */
+    foreach_out_edge(a, edge) {
+      const ir_node *user = edge->src;
+      if(get_nodes_block(user) == bb
+          && !is_Phi(user)
+					&& b != user
+          && value_dominates(b, user))
+        return 1;
+    }
+  }
+  return 0;
 }