tree-ssa-alias.c (new_type_alias): New procedure to create a type memory tag for a pointer with a may-alias set...

2005-05-29  Keith Besaw  <kbesaw@us.ibm.com>

        * tree-ssa-alias.c (new_type_alias): New procedure to
        create a type memory tag for a pointer with a may-alias
        set determined from a variable declaration.
        * tree-flow.h: export declaration of new_type_alias
        * tree-optimize.c (init_tree_optimization_passes): document
        that pass_may_alias cannot be called after pass_vectorize.
        * tree-vect-transform (vect_create_data_ref_ptr): Call
        new_type_alias when an type memory tag isn't available
        for a reference.
        (vectorizable_store): Use copy_virtual_operands to update
        virtual defs in place (so that loop_version can be called).
        Call mark_for_renaming for the virtual defs in case peeling
        is done and virtual uses outside the loop need to be updated.

From-SVN: r100322

1 files changed, 33 insertions, 0 deletions

diff --git a/gcc/tree-ssa-alias.c b/gcc/tree-ssa-alias.c
index 2ed712bea70..f8b992accd6 100644
--- a/gcc/tree-ssa-alias.c
+++ b/gcc/tree-ssa-alias.c
@@ -2776,6 +2776,39 @@ found_tag:
 }
 
 
+/* Create a type tag for PTR.  Construct the may-alias list of this type tag
+   so that it has the aliasing of VAR.  */
+
+void
+new_type_alias (tree ptr, tree var)
+{
+  var_ann_t p_ann = var_ann (ptr);
+  tree tag_type = TREE_TYPE (TREE_TYPE (ptr));
+  var_ann_t v_ann = var_ann (var);
+  tree tag;
+  subvar_t svars;
+
+  gcc_assert (p_ann->type_mem_tag == NULL_TREE);
+  gcc_assert (v_ann->mem_tag_kind == NOT_A_TAG);
+  tag = create_memory_tag (tag_type, true);
+  p_ann->type_mem_tag = tag;
+
+  /* Add VAR to the may-alias set of PTR's new type tag.  If VAR has
+     subvars, add the subvars to the tag instead of the actual var.  */
+  if (var_can_have_subvars (var)
+      && (svars = get_subvars_for_var (var)))
+    {
+      subvar_t sv;      
+      for (sv = svars; sv; sv = sv->next)
+        add_may_alias (tag, sv->var);
+    }
+  else
+    add_may_alias (tag, var);
+
+  /* Note, TAG and its set of aliases are not marked for renaming.  */
+}
+
+
 /* This structure is simply used during pushing fields onto the fieldstack
    to track the offset of the field, since bitpos_of_field gives it relative
    to its immediate containing type, and we want it relative to the ultimate