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[pf3gnuchains/gcc-fork.git] / gcc / tree-ssa-copyrename.c

diff --git a/gcc/tree-ssa-copyrename.c b/gcc/tree-ssa-copyrename.c
index c236de3..3e01b6e 100644 (file)
--- a/gcc/tree-ssa-copyrename.c
+++ b/gcc/tree-ssa-copyrename.c
@@ -1,5 +1,5 @@
 /* Rename SSA copies.
-   Copyright (C) 2004, 2006, 2007, 2008, 2009, 2010
+   Copyright (C) 2004, 2006, 2007, 2008, 2009, 2010, 2011
    Free Software Foundation, Inc.
    Contributed by Andrew MacLeod <amacleod@redhat.com>
 
@@ -28,7 +28,6 @@ along with GCC; see the file COPYING3.  If not see
 #include "flags.h"
 #include "basic-block.h"
 #include "function.h"
-#include "diagnostic.h"
 #include "tree-pretty-print.h"
 #include "bitmap.h"
 #include "tree-flow.h"
@@ -41,6 +40,12 @@ along with GCC; see the file COPYING3.  If not see
 #include "tree-pass.h"
 #include "langhooks.h"
 
+static struct
+{
+  /* Number of copies coalesced.  */
+  int coalesced;
+} stats;
+
 /* The following routines implement the SSA copy renaming phase.
 
    This optimization looks for copies between 2 SSA_NAMES, either through a
@@ -171,7 +176,7 @@ copy_rename_partition_coalesce (var_map map, tree var1, tree var2, FILE *debug)
       return false;
     }
 
-  /* Never attempt to coalesce 2 difference parameters.  */
+  /* Never attempt to coalesce 2 different parameters.  */
   if (TREE_CODE (root1) == PARM_DECL && TREE_CODE (root2) == PARM_DECL)
     {
       if (debug)
@@ -227,8 +232,25 @@ copy_rename_partition_coalesce (var_map map, tree var1, tree var2, FILE *debug)
       ign2 = false;
     }
 
-  /* Don't coalesce if the two variables aren't type compatible.  */
-  if (!types_compatible_p (TREE_TYPE (root1), TREE_TYPE (root2)))
+  /* Don't coalesce if the new chosen root variable would be read-only.
+     If both ign1 && ign2, then the root var of the larger partition
+     wins, so reject in that case if any of the root vars is TREE_READONLY.
+     Otherwise reject only if the root var, on which replace_ssa_name_symbol
+     will be called below, is readonly.  */
+  if ((TREE_READONLY (root1) && ign2) || (TREE_READONLY (root2) && ign1))
+    {
+      if (debug)
+       fprintf (debug, " : Readonly variable.  No coalesce.\n");
+      return false;
+    }
+
+  /* Don't coalesce if the two variables aren't type compatible .  */
+  if (!types_compatible_p (TREE_TYPE (root1), TREE_TYPE (root2))
+      /* There is a disconnect between the middle-end type-system and
+         VRP, avoid coalescing enum types with different bounds.  */
+      || ((TREE_CODE (TREE_TYPE (root1)) == ENUMERAL_TYPE
+          || TREE_CODE (TREE_TYPE (root2)) == ENUMERAL_TYPE)
+         && TREE_TYPE (root1) != TREE_TYPE (root2)))
     {
       if (debug)
        fprintf (debug, " : Incompatible types.  No coalesce.\n");
@@ -274,6 +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
@@ -333,20 +357,22 @@ 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));
     }
 
+  statistics_counter_event (cfun, "copies coalesced",
+                           stats.coalesced);
   delete_var_map (map);
   return updated ? TODO_remove_unused_locals : 0;
 }
@@ -374,6 +400,6 @@ struct gimple_opt_pass pass_rename_ssa_copies =
   0,                                   /* properties_provided */
   0,                                   /* properties_destroyed */
   0,                                   /* todo_flags_start */
-  TODO_dump_func | TODO_verify_ssa      /* todo_flags_finish */
+  TODO_verify_ssa                       /* todo_flags_finish */
  }
 };