2012-10-15 Easwaran Raman <eraman@google.com>

        * optabs.c (emit_cmp_and_jump_insn_1): Add a new parameter to
        specificy the probability of taking the jump.
        (emit_cmp_and_jump_insns): Likewise.
        (expand_compare_and_swap_loop): Make the jump predicted not taken.
        * dojump.c (do_compare_rtx_and_jump): Remove the code attaching
        REG_BR_PROB note and pass probability to emit_cmp_and_jump_insns.
        * cfgbuild.c (compute_outgoing_frequencies): Do not guess outgoing
        probabilities for branches with more than two successors.
        * expr.c (emit_block_move_via_loop): Predict the loop backedge loop
        to be highly taken.
        (try_casesi): Pass the probability of jumping to the default label.
        (try_tablejump): Likewise.
        (do_tablejump): Likewise.
        * expr.h (try_tablejump): Add a new parameter.
        (try_casesi): Likewise.
        (emit_cmp_and_jump_insns): Add probability as default parameter with a
        default value of -1.
        * except.c (sjlj_emit_function_enter): Pass probability to
        emit_cmp_and_jump_insns.
        * stmt.c (case_node): Add new fields PROB and SUBTREE_PROB.
        (do_jump_if_equal): Pass probability for REG_BR_PROB note.
        (add_case_node): Pass estimated probability of jumping to the case
        label.
        (emit_case_decision_tree): Pass default_prob to emit_case_nodes.
        (get_outgoing_edge_probs): New function.
        (conditional_probability): Likewise.
        (reset_out_edges_aux): Likewise.
        (compute_cases_per_edge): Likewise.
        (emit_case_dispatch_table): Update probabilities of edges coming out
        of the switch statement.
        (expand_case): Compute and propagate default edge probability to
        emit_case_dispatch_table.
        (expand_sjlj_dispatch_table): Update calls to add_case_node and
        emit_case_dispatch_table.
        (balance_case_nodes): Update subtree_prob values.
        (emit_case_nodes): Compute edge probabilities and add pass them to
        emit_cmp_and_jump_insns.

testsuite/ChangeLog:
2012-10-15   Easwaran Raman  <eraman@google.com> 
        * gcc.dg/tree-prof/switch-case-1.c: New test case.
        * gcc.dg/tree-prof/switch-case-2.c: New test case.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@192488 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 22 insertions, 3 deletions

diff --git a/gcc/cfgbuild.c b/gcc/cfgbuild.c
index 07ef949d20e..6e5c6ef75a7 100644
--- a/gcc/cfgbuild.c
+++ b/gcc/cfgbuild.c
@@ -559,16 +559,35 @@ compute_outgoing_frequencies (basic_block b)
 	  f->count = b->count - e->count;
 	  return;
 	}
+      else
+        {
+          guess_outgoing_edge_probabilities (b);
+        }
     }
-
-  if (single_succ_p (b))
+  else if (single_succ_p (b))
     {
       e = single_succ_edge (b);
       e->probability = REG_BR_PROB_BASE;
       e->count = b->count;
       return;
     }
-  guess_outgoing_edge_probabilities (b);
+  else
+    {
+      /* We rely on BBs with more than two successors to have sane probabilities
+         and do not guess them here. For BBs terminated by switch statements
+         expanded to jump-table jump, we have done the right thing during
+         expansion. For EH edges, we still guess the probabilities here.  */
+      bool complex_edge = false;
+      FOR_EACH_EDGE (e, ei, b->succs)
+        if (e->flags & EDGE_COMPLEX)
+          {
+            complex_edge = true;
+            break;
+          }
+      if (complex_edge)
+        guess_outgoing_edge_probabilities (b);
+    }
+
   if (b->count)
     FOR_EACH_EDGE (e, ei, b->succs)
       e->count = ((b->count * e->probability + REG_BR_PROB_BASE / 2)