PR100281 C++: Fix SImode pointer handling

The problem appears to be triggered by two locations in the front-end
where non-POINTER_SIZE pointers aren't handled right now.

1. An assertion in strip_typedefs is triggered because the alignment
of the types don't match. This in turn is caused by creating the new
type with build_pointer_type instead of taking the type of the
original pointer into account.

2. An assertion in cp_convert_to_pointer is triggered which expects
the target type to always have POINTER_SIZE.

gcc/cp/ChangeLog:

	PR c++/100281
	* cvt.c (cp_convert_to_pointer): Use the size of the target
	pointer type.
	* tree.c (cp_build_reference_type): Call
	cp_build_reference_type_for_mode with VOIDmode.
	(cp_build_reference_type_for_mode): Rename from
	cp_build_reference_type.  Add MODE argument and invoke
	build_reference_type_for_mode.
	(strip_typedefs): Use build_pointer_type_for_mode and
	cp_build_reference_type_for_mode for pointers and references.

gcc/ChangeLog:

	PR c++/100281
	* tree.c (build_reference_type_for_mode)
	(build_pointer_type_for_mode): Pick pointer mode if MODE argument
	is VOIDmode.
	(build_reference_type, build_pointer_type): Invoke
	build_*_type_for_mode with VOIDmode.

gcc/testsuite/ChangeLog:

	PR c++/100281
	* g++.target/s390/pr100281-1.C: New test.
	* g++.target/s390/pr100281-2.C: New test.

2 files changed, 20 insertions, 7 deletions

diff --git a/gcc/cp/cvt.c b/gcc/cp/cvt.c
index f1687e8..7fa6e8d 100644
--- a/gcc/cp/cvt.c
+++ b/gcc/cp/cvt.c
@@ -232,7 +232,7 @@ cp_convert_to_pointer (tree type, tree expr, bool dofold,
     {
       if (TYPE_PRECISION (intype) == POINTER_SIZE)
 	return build1 (CONVERT_EXPR, type, expr);
-      expr = cp_convert (c_common_type_for_size (POINTER_SIZE, 0), expr,
+      expr = cp_convert (c_common_type_for_size (TYPE_PRECISION (type), 0), expr,
 			 complain);
       /* Modes may be different but sizes should be the same.  There
 	 is supposed to be some integral type that is the same width
diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index 7f148b4..35faeff 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -1206,12 +1206,14 @@ vla_type_p (tree t)
   return false;
 }
 
-/* Return a reference type node referring to TO_TYPE.  If RVAL is
+
+/* Return a reference type node of MODE referring to TO_TYPE.  If MODE
+   is VOIDmode the standard pointer mode will be picked.  If RVAL is
    true, return an rvalue reference type, otherwise return an lvalue
    reference type.  If a type node exists, reuse it, otherwise create
    a new one.  */
 tree
-cp_build_reference_type (tree to_type, bool rval)
+cp_build_reference_type_for_mode (tree to_type, machine_mode mode, bool rval)
 {
   tree lvalue_ref, t;
 
@@ -1224,7 +1226,8 @@ cp_build_reference_type (tree to_type, bool rval)
       to_type = TREE_TYPE (to_type);
     }
 
-  lvalue_ref = build_reference_type (to_type);
+  lvalue_ref = build_reference_type_for_mode (to_type, mode, false);
+
   if (!rval)
     return lvalue_ref;
 
@@ -1250,7 +1253,7 @@ cp_build_reference_type (tree to_type, bool rval)
     SET_TYPE_STRUCTURAL_EQUALITY (t);
   else if (TYPE_CANONICAL (to_type) != to_type)
     TYPE_CANONICAL (t) 
-      = cp_build_reference_type (TYPE_CANONICAL (to_type), rval);
+      = cp_build_reference_type_for_mode (TYPE_CANONICAL (to_type), mode, rval);
   else
     TYPE_CANONICAL (t) = t;
 
@@ -1260,6 +1263,16 @@ cp_build_reference_type (tree to_type, bool rval)
 
 }
 
+/* Return a reference type node referring to TO_TYPE.  If RVAL is
+   true, return an rvalue reference type, otherwise return an lvalue
+   reference type.  If a type node exists, reuse it, otherwise create
+   a new one.  */
+tree
+cp_build_reference_type (tree to_type, bool rval)
+{
+  return cp_build_reference_type_for_mode (to_type, VOIDmode, rval);
+}
+
 /* Returns EXPR cast to rvalue reference type, like std::move.  */
 
 tree
@@ -1561,11 +1574,11 @@ strip_typedefs (tree t, bool *remove_attributes, unsigned int flags)
     {
     case POINTER_TYPE:
       type = strip_typedefs (TREE_TYPE (t), remove_attributes, flags);
-      result = build_pointer_type (type);
+      result = build_pointer_type_for_mode (type, TYPE_MODE (t), false);
       break;
     case REFERENCE_TYPE:
       type = strip_typedefs (TREE_TYPE (t), remove_attributes, flags);
-      result = cp_build_reference_type (type, TYPE_REF_IS_RVALUE (t));
+      result = cp_build_reference_type_for_mode (type, TYPE_MODE (t), TYPE_REF_IS_RVALUE (t));
       break;
     case OFFSET_TYPE:
       t0 = strip_typedefs (TYPE_OFFSET_BASETYPE (t), remove_attributes, flags);