* profile.c (compute_branch_probabilites): Compute probabilities

	for entry/exit edges; estimate probabilities for zero counts.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@47242 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2ecc65c..41a53e2 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+Wed Nov 21 12:38:37 CET 2001  Jan Hubicka
+
+       * profile.c (compute_branch_probabilites):  Compute probabilities
+       for entry/exit edges; estimate probabilities for zero counts.
+
 2001-11-21  Jakub Jelinek  <jakub@redhat.com>
 
        * explow.c (probe_stack_range): Use LCT_NORMAL as second argument

diff --git a/gcc/profile.c b/gcc/profile.c
index 57a1c72..1aea559 100644 (file)
--- a/gcc/profile.c
+++ b/gcc/profile.c
@@ -411,38 +411,32 @@ compute_branch_probabilities ()
   num_never_executed = 0;
   num_branches = 0;
 
-  for (i = 0; i < n_basic_blocks; i++)
+  for (i = 0; i <= n_basic_blocks + 1; i++)
     {
-      basic_block bb = BASIC_BLOCK (i);
+      basic_block bb = GCOV_INDEX_TO_BB (i);
       edge e;
       gcov_type total;
       rtx note;
 
       total = bb->count;
       if (total)
-       for (e = bb->succ; e; e = e->succ_next)
-         {
-             e->probability = (e->count * REG_BR_PROB_BASE + total / 2) / total;
-             if (e->probability < 0 || e->probability > REG_BR_PROB_BASE)
-               {
-                 error ("Corrupted profile info: prob for %d-%d thought to be %d",
-                        e->src->index, e->dest->index, e->probability);
-                 e->probability = REG_BR_PROB_BASE / 2;
-               }
-         }
-      if (any_condjump_p (bb->end)
-         && bb->succ->succ_next)
        {
-         int prob;
-         edge e;
-
-         if (total == 0)
-           prob = -1;
-         else
-         if (total == -1)
-           num_never_executed++;
-         else
+         for (e = bb->succ; e; e = e->succ_next)
            {
+               e->probability = (e->count * REG_BR_PROB_BASE + total / 2) / total;
+               if (e->probability < 0 || e->probability > REG_BR_PROB_BASE)
+                 {
+                   error ("Corrupted profile info: prob for %d-%d thought to be %d",
+                          e->src->index, e->dest->index, e->probability);
+                   e->probability = REG_BR_PROB_BASE / 2;
+                 }
+           }
+         if (bb->index >= 0
+             && any_condjump_p (bb->end)
+             && bb->succ->succ_next)
+           {
+             int prob;
+             edge e;
              int index;
 
              /* Find the branch edge.  It is possible that we do have fake
@@ -467,9 +461,37 @@ compute_branch_probabilities ()
                REG_NOTES (bb->end)
                  = gen_rtx_EXPR_LIST (REG_BR_PROB, GEN_INT (prob),
                                       REG_NOTES (bb->end));
+             num_branches++;
            }
-         num_branches++;
-
+       }
+      /* Otherwise distribute the probabilities evenly so we get sane sum.
+        Use simple heuristics that if there are normal edges, give all abnormals
+        frequency of 0, otherwise distribute the frequency over abnormals
+        (this is the case of noreturn calls).  */
+      else
+       {
+         for (e = bb->succ; e; e = e->succ_next)
+           if (!(e->flags & (EDGE_COMPLEX | EDGE_FAKE)))
+             total ++;
+         if (total)
+           {
+             for (e = bb->succ; e; e = e->succ_next)
+               if (!(e->flags & (EDGE_COMPLEX | EDGE_FAKE)))
+                 e->probability = REG_BR_PROB_BASE / total;
+               else
+                 e->probability = 0;
+           }
+         else
+           {
+             for (e = bb->succ; e; e = e->succ_next)
+               total ++;
+             for (e = bb->succ; e; e = e->succ_next)
+               e->probability = REG_BR_PROB_BASE / total;
+           }
+         if (bb->index >= 0
+             && any_condjump_p (bb->end)
+             && bb->succ->succ_next)
+           num_branches++, num_never_executed;
        }
     }