- at blockstart emit list of predblocks in comment

[libfirm] / ir / be / bera.c

diff --git a/ir/be/bera.c b/ir/be/bera.c
index ed07567..2178ec7 100644 (file)
--- a/ir/be/bera.c
+++ b/ir/be/bera.c
@@ -14,32 +14,41 @@
 #include "irmode.h"
 #include "irdom.h"
 
+#include "beutil.h"
 #include "besched_t.h"
 #include "belive_t.h"
 
+static sched_timestep_t get_time_step(const ir_node *irn)
+{
+       if(is_Phi(irn))
+               return 0;
+
+       return sched_get_time_step(irn);
+}
+
 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);
+       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);
+       /*
+        * 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;
-  }
+       /*
+        * Dominance is determined by the time steps of the schedule.
+        */
+       } else {
+               sched_timestep_t as = get_time_step(a);
+               sched_timestep_t bs = get_time_step(b);
+               res = as <= bs;
+       }
 
-  return res;
+       return res;
 }
 
 /**
@@ -48,51 +57,51 @@ int value_dominates(const ir_node *a, const ir_node *b)
  * @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)
+int values_interfere(const be_lv_t *lv, const ir_node *a, const ir_node *b)
 {
-  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;
-  }
+       int a2b = value_dominates(a, b);
+       int b2a = value_dominates(b, a);
 
-  /*
-   * 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;
+       /* If there is no dominance relation, they do not interfere. */
+       if((a2b | b2a) > 0) {
+               const ir_edge_t *edge;
+               ir_node *bb;
 
-    /* Look at all usages of a */
-    foreach_out_edge(a, edge) {
-      const ir_node *user = edge->src;
+               /*
+                * 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 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));
-      }
+               bb = get_nodes_block(b);
 
-      /* If b dominates a user of a, we can safely return 1 here. */
-      if(value_dominates(b, user))
-        return 1;
-    }
+               /*
+                * If a is live end in b's block it is
+                * live at b's definition (a dominates b)
+                */
+               if(be_is_live_end(lv, 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 = get_edge_src_irn(edge);
+                       if(get_nodes_block(user) == bb && !is_Phi(user) && b != user && value_dominates(b, user))
+                               return 1;
+               }
   }
-
   return 0;
 }