Cap frequency of recursive calls by 90%

	* predict.c (estimate_bb_frequencies): Cap recursive calls by 90%.

diff --git a/gcc/predict.c b/gcc/predict.c
index a7ae977c866cd1927bda328882a4f060a043ff8c..0a317a7a4ac4a9701aa01d3ab9226d5573d707f1 100644 (file)
--- a/gcc/predict.c
+++ b/gcc/predict.c
@@ -3892,7 +3892,30 @@ estimate_bb_frequencies (bool force)
       cfun->cfg->count_max = profile_count::uninitialized ();
       FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR_FOR_FN (cfun), NULL, next_bb)
        {
-         sreal tmp = BLOCK_INFO (bb)->frequency * freq_max + sreal (1, -1);
+         sreal tmp = BLOCK_INFO (bb)->frequency;
+         if (tmp >= 1)
+           {
+             gimple_stmt_iterator gsi;
+             tree decl;
+
+             /* Self recursive calls can not have frequency greater than 1
+                or program will never terminate.  This will result in an
+                inconsistent bb profile but it is better than greatly confusing
+                IPA cost metrics.  */
+             for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+               if (is_gimple_call (gsi_stmt (gsi))
+                   && (decl = gimple_call_fndecl (gsi_stmt (gsi))) != NULL
+                   && recursive_call_p (current_function_decl, decl))
+                 {
+                   if (dump_file)
+                     fprintf (dump_file, "Dropping frequency of recursive call"
+                              " in bb %i from %f\n", bb->index,
+                              tmp.to_double ());
+                   tmp = (sreal)9 / (sreal)10;
+                   break;
+                 }
+           }
+         tmp = tmp * freq_max + sreal (1, -1);
          profile_count count = profile_count::from_gcov_type (tmp.to_int ());  
 
          /* If we have profile feedback in which this function was never