[PATCH] Fixup copyrename statistics

[Richard Guenther]

I noticed we forget to clear the stats and that we do 1:1
replacements.

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.

Richard.

2011-07-12  Richard Guenther  <rguent...@suse.de>

        * tree-ssa-copyrename.c (rename_ssa_copies): Zero statistics.
        Do not perform no-op changes.

Index: gcc/tree-ssa-copyrename.c
===================================================================
--- gcc/tree-ssa-copyrename.c   (revision 176196)
+++ gcc/tree-ssa-copyrename.c   (working copy)
@@ -296,6 +296,8 @@ rename_ssa_copies (void)
   FILE *debug;
   bool updated = false;
 
+  memset (&stats, 0, sizeof (stats));
+
   if (dump_file && (dump_flags & TDF_DETAILS))
     debug = dump_file;
   else
@@ -355,16 +357,15 @@ rename_ssa_copies (void)
       if (!part_var)
         continue;
       var = ssa_name (x);
+      if (SSA_NAME_VAR (var) == SSA_NAME_VAR (part_var))
+       continue;
       if (debug)
         {
-         if (SSA_NAME_VAR (var) != SSA_NAME_VAR (part_var))
-           {
-             fprintf (debug, "Coalesced ");
-             print_generic_expr (debug, var, TDF_SLIM);
-             fprintf (debug, " to ");
-             print_generic_expr (debug, part_var, TDF_SLIM);
-             fprintf (debug, "\n");
-           }
+         fprintf (debug, "Coalesced ");
+         print_generic_expr (debug, var, TDF_SLIM);
+         fprintf (debug, " to ");
+         print_generic_expr (debug, part_var, TDF_SLIM);
+         fprintf (debug, "\n");
        }
       stats.coalesced++;
       replace_ssa_name_symbol (var, SSA_NAME_VAR (part_var));