Added interference test function

diff --git a/ir/be/bera.c b/ir/be/bera.c
index 7bddee0..4bcc69c 100644 (file)
--- a/ir/be/bera.c
+++ b/ir/be/bera.c
@@ -9,9 +9,11 @@
 
 #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 *)
 
@@ -23,3 +25,102 @@ void be_ra_init(void)
        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 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;
+}

diff --git a/ir/be/bera.h b/ir/be/bera.h
new file mode 100644 (file)
index 0000000..cb64fa6
--- /dev/null
+++ b/ir/be/bera.h
@@ -0,0 +1,20 @@
+/**
+ * Register allocation functions.
+ * @author Sebastian Hack
+ * @date 13.1.2005
+ */
+
+#ifndef _BERA_H
+#define _BERA_H
+
+#include "irnode.h"
+
+/**
+ * Check, if two values interfere.
+ * @param a The first value.
+ * @param b The second value.
+ * @return 1, if @p a and @p b interfere, 0 if not.
+ */
+int values_interfere(const ir_node *a, const ir_node *b);
+
+#endif /* _BERA_H */

diff --git a/ir/be/bera_t.h b/ir/be/bera_t.h
index 7bacf03..f14875b 100644 (file)
--- a/ir/be/bera_t.h
+++ b/ir/be/bera_t.h
@@ -10,6 +10,8 @@
 #include "firm_config.h"
 #include "bitset.h"
 
+#include "bera.h"
+
 #define DBG_BERA "firm.be.ra"
 
 typedef struct _ra_node_info_t {