PR bootstrap/66448

	PR bootstrap/66448
	* dwarf2out.c (check_die): Check for common duplicate attributes.
	(add_location_or_const_value_attribute): Do not add duplicate
	attributes.
	(gen_formal_parameter_die): Do not add DW_AT_artificial the second
	time around.
	(gen_struct_or_union_type_die): Bail early if TREE_ASM_WRITTEN.
	(gen_type_die_with_usage): Call check_die.
	(dwarf2out_decl): Only call check_die() when ENABLE_CHECKING.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@224393 138bc75d-0d04-0410-961f-82ee72b054a4