2009-05-25 Richard Guenther <rguenther@suse.de>

	PR tree-optimization/36327
	* tree-ssa-alias.c (walk_non_aliased_vuses): Add second walker
	callback for reference translation or lookup at the point
	of may-defs.
	* tree-ssa-alias.h (walk_non_aliased_vuses): Adjust prototype.
	* tree-ssa-sccvn.c (get_ref_from_reference_ops): Bail out
	for union COMPONENT_REFs.
	(vn_reference_lookup_3): New callback.  Lookup from memset
	and CONSTRUCTOR assignment, translate through struct copies.
	(vn_reference_lookup_pieces): Make sure to not free the
	passed operands array.  Adjust walk_non_aliased_vuses call.
	(vn_reference_lookup): Adjust walk_non_aliased_vuses call,
	make sure we do not leak memory.

	* gcc.dg/tree-ssa/ssa-fre-24.c: New testcase.
	* gcc.dg/tree-ssa/ssa-fre-25.c: Likewise.
	* gcc.dg/tree-ssa/sra-2.c: Disable FRE.
	* gcc.dg/vect/no-vfa-vect-43.c: Adjust.
	* gcc.dg/vect/vect-40.c: Likewise.
	* gcc.dg/vect/vect-42.c: Likewise.
	* gcc.dg/vect/vect-46.c: Likewise.
	* gcc.dg/vect/vect-76.c: Likewise.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@147851 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 24 insertions, 2 deletions

diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index 5be39f00398..5bb1f82ad9b 100644
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -1086,11 +1086,19 @@ get_continuation_for_phi (gimple phi, tree ref, bitmap *visited)
    WALKER returns non-NULL the walk stops and its result is returned.
    At the end of a non-successful walk NULL is returned.
 
+   TRANSLATE if non-NULL is called with a pointer to REF, the virtual
+   use which definition is a statement that may clobber REF and DATA.
+   If TRANSLATE returns (void *)-1 the walk stops and NULL is returned.
+   If TRANSLATE returns non-NULL the walk stops and its result is returned.
+   If TRANSLATE returns NULL the walk continues and TRANSLATE is supposed
+   to adjust REF and *DATA to make that valid.
+
    TODO: Cache the vector of equivalent vuses per ref, vuse pair.  */
 
 void *
 walk_non_aliased_vuses (tree ref, tree vuse,
-			void *(*walker)(tree, tree, void *), void *data)
+			void *(*walker)(tree, tree, void *),
+			void *(*translate)(tree *, tree, void *),void *data)
 {
   bitmap visited = NULL;
   void *res;
@@ -1114,7 +1122,21 @@ walk_non_aliased_vuses (tree ref, tree vuse,
       else
 	{
 	  if (stmt_may_clobber_ref_p (def_stmt, ref))
-	    break;
+	    {
+	      if (!translate)
+		break;
+	      res = (*translate) (&ref, vuse, data);
+	      /* Failed lookup and translation.  */
+	      if (res == (void *)-1)
+		{
+		  res = NULL;
+		  break;
+		}
+	      /* Lookup succeeded.  */
+	      else if (res != NULL)
+		break;
+	      /* Translation succeeded, continue walking.  */
+	    }
 	  vuse = gimple_vuse (def_stmt);
 	}
     }