X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fbe%2Fbera.c;h=5ab11e943d4ebb14b57aa5bf21f1e6595622c70b;hb=77f1eeaeb90f2d231b0ccc2fcbe071a9b457e6c3;hp=7bddee0c00ff504278f96f19db6210a8fb76702f;hpb=9b060a71a2667ced8d103023eda0ff710e799867;p=libfirm

diff --git a/ir/be/bera.c b/ir/be/bera.c
index 7bddee0c0..5ab11e943 100644
--- a/ir/be/bera.c
+++ b/ir/be/bera.c
@@ -3,23 +3,115 @@
  * @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 *)
+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;
 
-size_t ra_irn_data_offset = 0;
-size_t ra_irg_data_offset = 0;
+			/*
+			 * If the definition of 'a' was found 'a' and 'b' interfere, if
+			 * 'b' is live here.
+			 */
+			if(irn == a)
+				return b_live;
 
-void be_ra_init(void)
+			/* 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)
 {
-	ra_irn_data_offset = register_additional_node_data(sizeof(ra_info_t));
-	ra_irg_data_offset = register_additional_graph_data(sizeof(void *));
+	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;
 }