[Bug middle-end/106833] Handle OPAQUE_TYPE in gimple_canonical_types_compatible_p

["linkw at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106833

Kewen Lin <linkw at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-checking
                 CC|                            |bergner at gcc dot gnu.org,
                   |                            |hubicka at gcc dot gnu.org,
                   |                            |rguenth at gcc dot gnu.org,
                   |                            |segher at gcc dot gnu.org
             Target|                            |powerpc*-linux-gnu

--- Comment #1 from Kewen Lin <linkw at gcc dot gnu.org> ---
IMHO this is an omission when we were adding supports for opaque type, const
__vector_quad and __vector_quad should be taken as canonical_types_compatible.

I wonder if we can simply take it just like what it handles for "Non-aggregate
types", for example:

diff --git a/gcc/tree.cc b/gcc/tree.cc
index 2f488e4467c..555e96c59d5 100644
--- a/gcc/tree.cc
+++ b/gcc/tree.cc
@@ -13510,6 +13510,7 @@ gimple_canonical_types_compatible_p (const_tree t1,
const_tree t2,
       || TREE_CODE (t1) == VECTOR_TYPE
       || TREE_CODE (t1) == COMPLEX_TYPE
       || TREE_CODE (t1) == OFFSET_TYPE
+      || TREE_CODE (t1) == OPAQUE_TYPE
       || POINTER_TYPE_P (t1))
     {
       /* Can't be the same type if they have different recision.  */

Or adding one default hook which does the similar thing, and then if one target
needs some target specific checks on its opaque type, one specific hook can be
provided.