tree.c (build_opaque_vector_type): Make opaque vectors variant types of the corresponding non-opaque type.

2011-09-29  Richard Guenther  <rguenther@suse.de>

	* tree.c (build_opaque_vector_type): Make opaque vectors
	variant types of the corresponding non-opaque type.  Make
	sure to share opaque vector types properly.

From-SVN: r179341

1 files changed, 19 insertions, 7 deletions

diff --git a/gcc/tree.c b/gcc/tree.c
index a53c9f4..bcdda50 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -9752,17 +9752,29 @@ build_vector_type (tree innertype, int nunits)
   return make_vector_type (innertype, nunits, VOIDmode);
 }
 
-/* Similarly, but takes the inner type and number of units, which must be
-   a power of two.  */
+/* Similarly, but builds a variant type with TYPE_VECTOR_OPAQUE set.  */
 
 tree
 build_opaque_vector_type (tree innertype, int nunits)
 {
-  tree t;
-  innertype = build_distinct_type_copy (innertype);
-  t = make_vector_type (innertype, nunits, VOIDmode);
-  TYPE_VECTOR_OPAQUE (t) = true;
-  return t;
+  tree t = make_vector_type (innertype, nunits, VOIDmode);
+  tree cand;
+  /* We always build the non-opaque variant before the opaque one,
+     so if it already exists, it is TYPE_NEXT_VARIANT of this one.  */
+  cand = TYPE_NEXT_VARIANT (t);
+  if (cand
+      && TYPE_VECTOR_OPAQUE (cand)
+      && check_qualified_type (cand, t, TYPE_QUALS (t)))
+    return cand;
+  /* Othewise build a variant type and make sure to queue it after
+     the non-opaque type.  */
+  cand = build_distinct_type_copy (t);
+  TYPE_VECTOR_OPAQUE (cand) = true;
+  TYPE_CANONICAL (cand) = TYPE_CANONICAL (t);
+  TYPE_NEXT_VARIANT (cand) = TYPE_NEXT_VARIANT (t);
+  TYPE_NEXT_VARIANT (t) = cand;
+  TYPE_MAIN_VARIANT (cand) = TYPE_MAIN_VARIANT (t);
+  return cand;
 }