1 files changed, 43 insertions, 3 deletions

diff --git a/gcc/auto-profile.cc b/gcc/auto-profile.cc
index aa4d163..7e0e8c6 100644
--- a/gcc/auto-profile.cc
+++ b/gcc/auto-profile.cc
@@ -303,6 +303,10 @@ public:
      in INFO and return true; otherwise return false.  */
   bool get_count_info (gimple *stmt, count_info *info) const;
 
+  /* Find count_info for a given gimple location GIMPLE_LOC. If found,
+     store the count_info in INFO and return true; otherwise return false.  */
+  bool get_count_info (location_t gimple_loc, count_info *info) const;
+
   /* Find total count of the callee of EDGE.  */
   gcov_type get_callsite_total_count (struct cgraph_edge *edge) const;
 
@@ -724,11 +728,18 @@ autofdo_source_profile::get_function_instance_by_decl (tree decl) const
 bool
 autofdo_source_profile::get_count_info (gimple *stmt, count_info *info) const
 {
-  if (LOCATION_LOCUS (gimple_location (stmt)) == cfun->function_end_locus)
+  return get_count_info (gimple_location (stmt), info);
+}
+
+bool
+autofdo_source_profile::get_count_info (location_t gimple_loc,
+					count_info *info) const
+{
+  if (LOCATION_LOCUS (gimple_loc) == cfun->function_end_locus)
     return false;
 
   inline_stack stack;
-  get_inline_stack (gimple_location (stmt), &stack);
+  get_inline_stack (gimple_loc, &stack);
   if (stack.length () == 0)
     return false;
   function_instance *s = get_function_instance_by_inline_stack (stack);
@@ -1130,7 +1141,36 @@ afdo_set_bb_count (basic_block bb, const stmt_set &promoted)
     }
 
   if (!has_annotated)
-    return false;
+    {
+      /* For an empty BB with all debug stmt which assigne a value with
+	 constant, check successors PHIs corresponding to the block and
+	 use those counts.  */
+      edge tmp_e;
+      edge_iterator tmp_ei;
+      FOR_EACH_EDGE (tmp_e, tmp_ei, bb->succs)
+	{
+	  basic_block bb_succ = tmp_e->dest;
+	  for (gphi_iterator gpi = gsi_start_phis (bb_succ);
+	       !gsi_end_p (gpi);
+	       gsi_next (&gpi))
+	    {
+	      gphi *phi = gpi.phi ();
+	      location_t phi_loc
+		= gimple_phi_arg_location_from_edge (phi, tmp_e);
+	      count_info info;
+	      if (afdo_source_profile->get_count_info (phi_loc, &info)
+		  && info.count != 0)
+		{
+		  if (info.count > max_count)
+		    max_count = info.count;
+		  has_annotated = true;
+		}
+	    }
+	}
+
+      if (!has_annotated)
+	return false;
+    }
 
   for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
     afdo_source_profile->mark_annotated (gimple_location (gsi_stmt (gsi)));