X-Git-Url: http://git.sourceforge.jp/view?a=blobdiff_plain;f=gcc%2Ftree-ssa-copyrename.c;h=ae4fb5fba396700681b09be12e8bbb236c7498a6;hb=046f323efd9149bb5d2d5638466e98ed238b7635;hp=41d43a6179cd7effea9107c08f03a4af43472df7;hpb=8e3cb73bc66100e137b20bcd98316bc415b6e53c;p=pf3gnuchains%2Fgcc-fork.git

diff --git a/gcc/tree-ssa-copyrename.c b/gcc/tree-ssa-copyrename.c
index 41d43a6179c..ae4fb5fba39 100644
--- 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>
 
@@ -40,6 +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
@@ -170,7 +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)
@@ -226,8 +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");
@@ -343,9 +366,12 @@ rename_ssa_copies (void)
 	      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;
 }