re PR c++/90383 (GCC generates invalid constexpr copy/move assignment operators for types with trailing padding. (Again))

	PR c++/90383
	* tree-inline.h (struct copy_body_data): Add do_not_fold member.
	* tree-inline.c (remap_gimple_op_r): Avoid folding expressions if
	id->do_not_fold.
	(copy_tree_body_r): Likewise.
	(copy_fn): Set id.do_not_fold to true.

	* g++.dg/cpp1y/constexpr-90383-1.C: New test.
	* g++.dg/cpp1y/constexpr-90383-2.C: New test.

From-SVN: r271058